JP7237439B1 - Transmissive liquid crystal display device, electronic equipment - Google Patents

Abstract

An object of the present invention is to provide a high-quality liquid crystal display device with excellent viewing angle characteristics. A pixel includes a first switch, a second switch, a third switch, a first resistor, a second resistor, a first liquid crystal element, and a second liquid crystal element. , the pixel electrode of the first liquid crystal element is electrically connected to a signal line through the first switch, and the pixel electrode of the first liquid crystal element is connected to the second switch and the The pixel electrode of the second liquid crystal element is electrically connected to the pixel electrode of the second liquid crystal element through the first resistor, and the pixel electrode of the second liquid crystal element is connected to the Cs line through the third switch and the second resistor. and the common electrode of the first liquid crystal element is electrically connected to the common electrode of the second liquid crystal element, and a potential corresponding to the gradation of the pixel is applied to the signal line. By inputting, a high-quality display with excellent viewing angle characteristics can be obtained. [Selection drawing] Fig. 1

Description

The present invention relates to an article, method, or method of producing an article. In particular, it relates to display devices or semiconductor devices. Furthermore, the present invention relates to an electronic device having the display device as a display portion.

Liquid crystal display devices are used in many electronic products such as mobile phones and television receivers, and much research is being conducted to further improve the quality.

A liquid crystal display device has the advantages of being smaller and lighter than a CRT (cathode-ray tube) and consuming less power, but has the problem of a narrow viewing angle. In recent years, many studies have been made on a multi-domain method, that is, an orientation division method, in order to improve viewing angle characteristics. For example, the MVA method (Multi-domain Vertical Al
multi-domain type vertical alignment system) and PVA system (Patterned
Vertical Alignment; pattern type vertical alignment system) and the like.

Research is also being conducted to improve the viewing angle by dividing one pixel into a plurality of sub-pixels and varying the alignment state of liquid crystal in each sub-pixel (Patent Document 1).

JP 2006-276582 A

However, it cannot be said that the viewing angle characteristics are sufficient, and further improvement is required as a display device. Accordingly, it is an object of the present invention to provide a higher quality display device with excellent viewing angle characteristics.

FIG. 77 shows an equivalent circuit diagram of one pixel of the liquid crystal display device described in Patent Document 1. In FIG. Figure 7
7 has a TFT 30, a liquid crystal capacitor L1, a liquid crystal capacitor L2, a storage capacitor C1 and a storage capacitor C2, and is connected to a scanning line 3a and a data line (signal line) 6a.

Although the liquid crystal exhibits a voltage retention characteristic, the retention rate is not 100%, and there is concern about the presence of leakage due to electric charge flowing through the liquid crystal. In the pixel shown in FIG. 77, when leakage occurs, the state in which a constant potential is maintained by the law of conservation of electric charge in the portion closed by the storage capacitor C1, the storage capacitor C2, and the liquid crystal capacitor L2 at the node 11 is lost. , the potential of node 11 becomes far from the potential in the initial state before leakage occurs. Therefore, the transmittance of the liquid crystal capacitor L2 is
The transmittance changes from that determined by the image signal written to the data line 6a, that is, the potential corresponding to the gradation. As a result, the desired gradation cannot be obtained, or the image quality deteriorates. In this manner, the display quality is gradually degraded over time. Therefore, the life of the product is shortened. In particular, a normally black mode display device cannot display black, resulting in a decrease in contrast.

In view of the above problems, an object of the present invention is to realize a wide viewing angle display. Another object is to provide a display device with excellent contrast. Another object is to provide a display device with excellent display quality. Alternatively, another object is to provide a display device that is less susceptible to noise and can display clear images. Alternatively, an object is to provide a display device in which display deterioration is less likely to occur. Alternatively, an object is to provide a display device with excellent product life.

One aspect of the present invention includes a first switch, a second switch, a third switch, a first resistor, a second resistor, a first liquid crystal element, and a second liquid crystal element. each of the first liquid crystal element and the second liquid crystal element includes at least a pixel electrode, a common electrode, and liquid crystal controlled by the pixel electrode and the common electrode; The pixel electrode of the liquid crystal element of 1 is
The pixel electrode of the first liquid crystal element is electrically connected to the first wiring through the first switch, and the pixel electrode of the first liquid crystal element is connected to the second liquid crystal element through the second switch and the first resistor. and the pixel electrode of the second liquid crystal element is electrically connected to a second wiring through the third switch and the second resistor. It is a liquid crystal display device.

One aspect of the present invention includes a first switch, a second switch, a third switch, a first resistor, a second resistor, a first liquid crystal element, a second liquid crystal element, A pixel including a first storage capacitor and a second storage capacitor is provided, and each of the first liquid crystal element and the second liquid crystal element includes at least a pixel electrode, a common electrode, the pixel electrode and the The pixel electrode of the first liquid crystal element is electrically connected to the first wiring through the first switch, and the pixel of the first liquid crystal element An electrode is electrically connected to the pixel electrode of the second liquid crystal element through the second switch and the first resistor, and the pixel electrode of the second liquid crystal element is connected to the third switch and the first resistor. It is electrically connected to the second wiring through the second resistor, and the pixel electrode of the first liquid crystal element is electrically connected to the second wiring through the first storage capacitor. , the pixel electrode of the second liquid crystal element is connected to the second liquid crystal element through the second storage capacitor.
The liquid crystal display device is characterized by being electrically connected to the wiring of the .

One aspect of the present invention is the liquid crystal display device having the above structure, wherein the resistance value of the second resistor is higher than the resistance value of the first resistor.

One aspect of the present invention includes a switch, a first transistor, a second transistor, a first liquid crystal element, a second liquid crystal element, a first storage capacitor, and a second storage capacitor. has a pixel,
Each of the first liquid crystal element and the second liquid crystal element includes at least a pixel electrode, a common electrode,
The pixel electrode and the liquid crystal controlled by the common electrode, the pixel electrode of the first liquid crystal element is electrically connected to the first wiring through the switch, and the first liquid crystal element is electrically connected to the pixel electrode of the second liquid crystal element through the first transistor, and the pixel electrode of the second liquid crystal element is electrically connected to the pixel electrode of the second liquid crystal element through the second transistor. The pixel electrode of the first liquid crystal element is electrically connected to the second wiring through the first storage capacitor, and the pixel electrode of the second liquid crystal element is electrically connected to is a liquid crystal display device electrically connected to the second wiring through the second storage capacitor.

One aspect of the present invention is a first transistor, a second transistor, a third transistor, a first liquid crystal element, a second liquid crystal element, a first storage capacitor, and a second storage capacitor. Each of the first liquid crystal element and the second liquid crystal element is composed of at least a pixel electrode, a common electrode, and liquid crystal controlled by the pixel electrode and the common electrode, A pixel electrode of the first liquid crystal element is electrically connected to the first wiring through the third transistor, and a pixel electrode of the first liquid crystal element is electrically connected to the first wiring through the first transistor. It is electrically connected to the pixel electrode of the second liquid crystal element, the pixel electrode of the second liquid crystal element is electrically connected to the second wiring through the second transistor, and the first liquid crystal element is electrically connected to the pixel electrode. A pixel electrode of the element is electrically connected to the second wiring via the first storage capacitor, and a pixel electrode of the second liquid crystal element is connected to the second wiring via the second storage capacitor. The liquid crystal display device is characterized by being electrically connected to the wiring of the .

One aspect of the present invention is that, in the above structure, where W is the channel width of the transistor and L is the channel length, W/L of the third transistor is greater than W/L of the first transistor or the second transistor. The liquid crystal display device is characterized by being small.

Another feature of the present invention is that, in the above structure, W/L of the second transistor is larger than W/L of the first transistor, where W is the channel width of the transistor and L is the channel length of the transistor. It is a liquid crystal display.

The display device of the present invention includes, for example, a liquid crystal display device, a light-emitting device having a light-emitting element represented by an organic light-emitting device (OLED) in each pixel, and a DMD (Digital Micromirror).
Device), PDP (Plasma Display Panel), FED (F
Active matrix display devices such as field emission displays are included in this category. It also includes a passive matrix display device.

Various types of switches can be used. Examples include electrical switches and mechanical switches. In other words, any device that can control the flow of current will suffice.
It is not limited to a specific one. For example, as a switch, a transistor (eg, bipolar transistor, MOS transistor, etc.), a diode (eg, PN diode, P
IN diode, Schottky diode, MIM (Metal Insulator
Metal) diode, MIS (Metal Insulator Semiconductor
uctor) diodes, diode-connected transistors, etc.), thyristors, and the like can be used. Alternatively, a logic circuit in which these are combined can be used as a switch.

Examples of mechanical switches include digital micromirror devices (DMD),
There are switches using MEMS (micro-electro-mechanical system) technology. The switch has an electrode that can be moved mechanically, and operates by controlling connection and disconnection by moving the electrode.

When a transistor is used as a switch, the transistor simply operates as a switch; therefore, the polarity (conductivity type) of the transistor is not particularly limited. However, when it is desired to suppress off-state current, it is preferable to use a transistor having a polarity with a smaller off-state current. As a transistor with low off-state current, there are a transistor having an LDD region, a transistor having a multi-gate structure, and the like. Alternatively, in the case where the potential of the source terminal of the transistor operated as a switch operates in a state close to the potential of the low-potential power supply (Vss, GND, 0 V, etc.), it is desirable to use an N-channel transistor. On the contrary, it is desirable to use a P-channel transistor when operating in a state where the potential of the source terminal is close to the potential of the high-potential power supply (such as Vdd). This is because when an N-channel transistor operates in a state where the source terminal is close to the potential of the power supply on the low potential side, and when a P-channel transistor operates in a state where the source terminal is close to the potential on the high potential side power supply, the gate and source This is because the absolute value of the voltage between them can be increased, so that they can easily operate as a switch. Also, since the source follower operation is less likely to occur, the magnitude of the output voltage is less likely to decrease.

Note that CMOS
A switch of the type may be used as the switch. When a CMOS type switch is used, current flows when either one of the P-channel type transistor and the N-channel type transistor is turned on, so that the CMOS type switch easily functions as a switch. For example, the voltage can be output appropriately regardless of whether the voltage of the input signal to the switch is high or low. Furthermore, since the voltage amplitude value of the signal for turning on and off the switch can be reduced, power consumption can also be reduced.

Note that when a transistor is used as a switch, the switch has an input terminal (one of the source terminal and the drain terminal), an output terminal (the other of the source terminal and the drain terminal), and a terminal for controlling conduction (gate terminal). are doing. On the other hand, when a diode is used as a switch, the switch may not have a terminal for controlling conduction. Therefore, using a diode as a switch rather than a transistor can reduce wiring for controlling terminals.

Note that when explicitly describing that A and B are connected, the case where A and B are electrically connected and the case where A and B are functionally connected , where A and B are directly connected. Here, A and B are objects (for example, devices, elements, circuits, wiring, electrodes, terminals, conductive films, layers, etc.). Therefore, given connection relations,
For example, it is not limited to the connection relationships shown in the diagrams or text, and includes connections other than those shown in the diagrams or text.

For example, when A and B are electrically connected, an element (for example, switch, transistor, capacitive element, inductor, resistive element, diode, etc.) that enables electrical connection between A and B is , A and B. Alternatively, when A and B are functionally connected, a circuit that enables functional connection between A and B (for example, a logic circuit (inverter, NAND circuit, NOR circuit, etc.), a signal conversion circuit (DA conversion circuit, AD conversion circuit, gamma correction circuit, etc.), potential level conversion circuit (power supply circuit (booster circuit,
step-down circuits, etc.), level shifter circuits that change the potential level of signals, etc.), voltage sources, current sources,
Switching circuit, amplifier circuit (circuit that can increase signal amplitude or current amount, operational amplifier,
A differential amplifier circuit, a source follower circuit, a buffer circuit, etc.), a signal generation circuit, a memory circuit, a control circuit, etc.) may be arranged between A and B. Alternatively, assuming that A and B are directly connected, A and B
may be directly connected.

When it is explicitly stated that A and B are directly connected, it means that A and B are directly connected (that is, another element or other circuit is connected between A and B). A and B are electrically connected (that is, A and B are connected with another element or circuit interposed between them). (if any).

It should be noted that when it is explicitly stated that A and B are electrically connected, it means that A and B are electrically connected (that is, another element between A and B or another circuit) and A and B are functionally connected (that is, functionally connected with another circuit between A and B). and A and B are directly connected (that is, A and B are connected without another element or another circuit between them). In other words, the explicit description of "electrically connected" is the same as the explicit description of "connected".

Note that a display element, a display device having a display element, a light-emitting element, and a light-emitting device having a light-emitting element can have various modes and various elements. Examples of display elements, display devices, light-emitting elements, or light-emitting devices include EL elements (EL elements containing organic and inorganic substances, organic EL elements, and inorganic EL elements), electron-emitting elements, liquid crystal elements, electronic inks, electrophoretic elements, Grating Light Bulb (GLV), Plasma Display (PD)
P), a digital micromirror device (DMD), a piezoelectric ceramic display, a carbon nanotube, or the like, can be used as a display medium whose contrast, brightness, reflectance, transmittance, etc. are changed by electromagnetism. Examples of display devices using EL elements include EL displays, and examples of display devices using electron-emitting devices include field emission displays (FED) and SED type flat displays (SED: Surface-co
Liquid crystal displays (transmissive liquid crystal displays, semi-transmissive liquid crystal displays, reflective liquid crystal displays, direct view liquid crystal displays, projection liquid crystal displays), electronic inks, etc. Electronic paper is a display device using an electrophoretic element.

Note that an EL element is an element having an anode, a cathode, and an EL layer sandwiched between the anode and the cathode. Note that the EL layer utilizes light emission (fluorescence) from singlet excitons;
Those utilizing luminescence (phosphorescence) from doublet excitons, those utilizing luminescence (fluorescence) from singlet excitons, and those utilizing luminescence (phosphorescence) from triplet excitons , those formed by organic substances, those formed by inorganic substances, those formed by organic substances and those formed by inorganic substances, macromolecular materials, low-molecular-weight materials, high-molecular-weight materials and low-molecular-weight materials and the like can be used. However, it is not limited to this, E
Various things can be used as an L element.

An electron-emitting device is a device that extracts electrons by concentrating a high electric field on a sharp cathode. For example, as an electron-emitting device, a Spindt type, a carbon nanotube (CNT) type, a metal-insulator-metal stacked MIM (Metal-Insulator-Metal) type, a metal-insulator-semiconductor stacked MIS (Metal-Insulator -Semicon
thin film type such as inductor type, MOS type, silicon type, thin film diode type, diamond type, surface conduction emitter SCD type, diode type, diamond type, surface conduction emitter SCD type, metal-insulator-semiconductor-metal type, HEED type, EL type, porous silicon type, surface conduction (SED) type, and the like can be used. However, the electron-emitting device is not limited to this, and various devices can be used as the electron-emitting device.

Note that a liquid crystal element is an element that controls transmission or non-transmission of light by an optical modulation action of liquid crystal, and is composed of a pair of electrodes and liquid crystal. Note that the optical modulation action of the liquid crystal is controlled by an electric field (including a horizontal electric field, a vertical electric field, or an oblique electric field) applied to the liquid crystal. Liquid crystal elements include nematic liquid crystals, cholesteric liquid crystals, smectic liquid crystals, discotic liquid crystals, thermotropic liquid crystals, lyotropic liquid crystals, lyotropic liquid crystals, low molecular liquid crystals, polymer liquid crystals, ferroelectric liquid crystals, antiferroelectric liquid crystals, and main chains. type liquid crystal, side chain type polymer liquid crystal, plasma addressed liquid crystal (PDLC), banana type liquid crystal, TN (Twisted
Nematic) mode, STN (Super Twisted Nematic) mode, IPS (In-Plane-Switching) mode, FFS (Fringe
Field Switching) mode, MVA (Multi-domain Ver.)
alignment) mode, PVA (Patterned Vertic
alignment), ASV (Advanced Super View) mode, ASM (Axially Symmetrically aligned Micro-ce
ll) mode, OCB (Optical Compensated Birefring)
ence) mode, ECB (Electrically Controlled Bir
efringence) mode, FLC (Ferroelectric Liquid
Crystal) mode, AFLC (Anti-Ferroelectric Liqui
d Crystal) mode, PDLC (Polymer Dispersed Liq
uid Crystal) mode, guest host mode, etc. can be used. However, the liquid crystal element is not limited to this, and various liquid crystal elements can be used.

The electronic paper includes those displayed by molecules such as optical anisotropy and dye molecule orientation, those displayed by particles such as electrophoresis, particle movement, particle rotation, and phase change, and those in which one end of a film is Display by movement, display by color development/phase change of molecules, display by light absorption by molecules, display by self-emission due to combination of electrons and holes, etc. . For example, as electronic paper, microcapsule type electrophoresis, horizontal movement type electrophoresis, vertical movement type electrophoresis, spherical twist ball, magnetic twist ball, cylindrical twist ball system, charged toner, electronic liquid powder, magnetophoresis type, magnetic thermosensitive formula, electrowetting, light scattering (transparent cloudiness), cholesteric liquid crystal/photoconductive layer, cholesteric liquid crystal, bistable nematic liquid crystal, ferroelectric liquid crystal, dichroic dye/liquid crystal dispersion type, movable film, leuco dye disappearance Color, photochromic, electrochromic, electrodeposition, flexible organic EL, etc. can be used. However, it is not limited to
Various electronic papers can be used. Here, by using microcapsule-type electrophoresis, it is possible to solve the problem of aggregation and sedimentation of electrophoretic particles, which is a drawback of electrophoresis. Electronic liquid powder has advantages such as high-speed response, high reflectance, wide viewing angle, low power consumption, and good memory.

In the plasma display, a substrate having electrodes formed on its surface and a substrate having electrodes and fine grooves formed on its surface and a phosphor layer formed in the grooves are opposed to each other at a narrow interval, and a rare gas is enclosed. have a structure. In addition, display can be performed by generating ultraviolet rays by applying a voltage between the electrodes and causing the phosphor to glow. As a plasma display, DC
A type PDP or an AC type PDP may be used. Here, as a plasma display panel, AS
W (Address While Sustain) drive, ADS (Address Display Sep) dividing a subframe into a reset period, an address period, and a sustain period
arated) drive, CLEAR (Low Energy Address and R
Eduction of False Contour Sequence) drive, AL
IS (Alternate Lighting of Surfaces) method, TER
ES (Technology of Reciprocal Sustainer) drive or the like can be used. However, it is not limited to this, and various plasma displays can be used.

In addition, a display device that requires a light source, such as a liquid crystal display (transmissive liquid crystal display, transflective liquid crystal display, reflective liquid crystal display, direct view liquid crystal display, projection liquid crystal display), grating light valve (GLV) is used. Electroluminescence, cold-cathode tubes, hot-cathode tubes, LEDs, laser light sources, mercury lamps, and the like can be used as light sources for such display devices and display devices using a digital micromirror device (DMD). However, it is not limited to this, and various light sources can be used.

Note that various types of transistors can be used as the transistor. Therefore,
There is no limitation on the type of transistor to be used. For example, a thin film transistor (TFT) including a non-single-crystal semiconductor film typified by amorphous silicon, polycrystalline silicon, microcrystalline (also called microcrystalline or semi-amorphous) silicon, or the like can be used. The use of TFTs has various advantages. For example, since it can be manufactured at a lower temperature than in the case of single crystal silicon, it is possible to reduce the manufacturing cost or increase the size of the manufacturing apparatus. Since the manufacturing equipment can be made large, it can be manufactured on a large substrate. Therefore, since a large number of display devices can be manufactured at the same time, the manufacturing cost can be reduced. Furthermore, since the manufacturing temperature is low, a substrate with low heat resistance can be used. Therefore, a transistor can be manufactured on a transparent substrate. Transistors on a transparent substrate can then be used to control the transmission of light through the display element.
Alternatively, since the film thickness of the transistor is thin, part of the film forming the transistor can transmit light. Therefore, the aperture ratio can be improved.

By using a catalyst (such as nickel) when manufacturing polycrystalline silicon, crystallinity can be further improved, and a transistor with good electrical characteristics can be manufactured. As a result, gate driver circuits (scanning line driving circuits) and source driver circuits (signal line driving circuits)
, a signal processing circuit (a signal generation circuit, a gamma correction circuit, a DA conversion circuit, etc.) can be integrally formed on the substrate.

Note that crystallinity can be further improved by using a catalyst (such as nickel) when manufacturing microcrystalline silicon, so that a transistor with excellent electrical characteristics can be manufactured. At this time, the crystallinity can be improved only by heat treatment without laser light irradiation. As a result, a part of the gate driver circuit (scanning line driving circuit) and the source driver circuit (analog switch, etc.) can be integrally formed on the substrate. Furthermore, when laser light irradiation is not performed for crystallization, uneven crystallinity of silicon can be suppressed. Therefore, a clear image can be displayed.

However, it is possible to produce polycrystalline silicon and microcrystalline silicon without using a catalyst (such as nickel).

Note that it is desirable to improve the crystallinity of silicon to polycrystalline or microcrystalline for the entire panel, but the present invention is not limited to this. Crystallinity of silicon may be improved only in a partial region of the panel. It is possible to selectively improve the crystallinity by selectively irradiating laser light. For example, only the peripheral circuit region, which is a region other than pixels, may be irradiated with laser light. Alternatively, laser light may be applied only to regions such as the gate driver circuit and the source driver circuit. Alternatively, only a part of the source driver circuit (for example, analog switch) may be irradiated with laser light. resulting in,
Silicon crystallization can be improved only in areas where the circuit needs to operate at high speed. Since there is little need to operate the pixel region at high speed, the pixel circuit can be operated without problems even if the crystallinity is not improved. Since the region for improving the crystallinity can be reduced, the manufacturing process can be shortened, the throughput can be improved, and the manufacturing cost can be reduced. In addition, manufacturing can be performed with a small number of required manufacturing apparatuses, so manufacturing costs can be reduced.

Alternatively, a transistor can be formed using a semiconductor substrate, an SOI substrate, or the like. As a result, it is possible to manufacture small-sized transistors with little variation in characteristics, size, shape, etc., high current supply capability, and the like. By using these transistors, the power consumption of the circuit can be reduced or the circuit can be highly integrated.

Alternatively, a transistor including a compound semiconductor or oxide semiconductor such as ZnO, a-InGaZnO, SiGe, GaAs, IZO, ITO, or SnO, or a thin film transistor obtained by thinning any of these compound semiconductors or oxide semiconductors can be used. I can. As a result, the manufacturing temperature can be lowered, and for example, the transistor can be manufactured at room temperature. As a result, a transistor can be formed directly on a substrate having low heat resistance, such as a plastic substrate or a film substrate. Note that these compound semiconductors or oxide semiconductors are
It can be used not only for the channel portion of a transistor, but also for other purposes. For example, these compound semiconductors or oxide semiconductors can be used as resistance elements, pixel electrodes, and transparent electrodes. Furthermore, since they can be deposited or formed at the same time as the transistors, costs can be reduced.

Alternatively, a transistor or the like formed by an inkjet method or a printing method can be used. These allow fabrication at room temperature, in low vacuum, or on large substrates. In addition, since manufacturing can be performed without using a mask (reticle), the layout of transistors can be easily changed. Furthermore, since it is not necessary to use a resist, the material cost can be reduced and the number of steps can be reduced. Furthermore, since the film is applied only to the necessary portions, the material is not wasted and the cost can be reduced as compared with the manufacturing method in which the film is formed on the entire surface and then etched.

Alternatively, a transistor including an organic semiconductor, a carbon nanotube, or the like can be used. These allow a transistor to be formed on a bendable substrate.
Therefore, it can be strongly impact-resistant.

Furthermore, transistors with various structures can be used. For example, a MOS transistor, a junction transistor, a bipolar transistor, or the like can be used as the transistor. By using a MOS transistor, the size of the transistor can be reduced. Therefore, many transistors can be mounted. A large current can flow by using a bipolar transistor. Therefore, the circuit can be operated at high speed.

Note that a MOS transistor, a bipolar transistor, and the like may be mixed and formed on one substrate. As a result, low power consumption, miniaturization, high speed operation, etc. can be achieved.

In addition, various transistors can be used.

Note that the transistor can be formed using various substrates. The type of substrate is not limited to a specific one. Substrates on which transistors are formed include, for example, single crystal substrates, SOI substrates, glass substrates, quartz substrates, plastic substrates, paper substrates, cellophane substrates, stone substrates, wood substrates, cloth substrates (natural fibers (silk, cotton, hemp), ), synthetic fibers (nylon, polyurethane, polyester) or recycled fibers (acetate, cupra, rayon, recycled polyester), etc.), leather substrates, rubber substrates, stainless steel substrates, substrates with stainless steel foil, etc. can be used. Alternatively, the skin (epidermis, dermis) or subcutaneous tissue of animals such as humans may be used as the substrate. Alternatively, a transistor may be formed using one substrate, and then the transistor may be transferred to another substrate and placed over the other substrate. Substrates on which transistors are transferred include single crystal substrates, SOI substrates, glass substrates, quartz substrates, plastic substrates, paper substrates, cellophane substrates, stone substrates, wood substrates, cloth substrates (natural fibers (silk, cotton, hemp), Synthetic fibers (nylon, polyurethane, polyester) or recycled fibers (acetate, cupra, rayon, recycled polyester, etc.), leather substrates, rubber substrates, stainless steel substrates, substrates with stainless steel foil, etc. can be done. Or the skin of animals such as humans (epidermis, dermis)
Alternatively, subcutaneous tissue may be used as the substrate. Alternatively, a substrate may be used to form a transistor, and the substrate may be polished to be thin. Substrates to be polished include single crystal substrates and SOI substrates.
substrates, glass substrates, quartz substrates, plastic substrates, paper substrates, cellophane substrates, stone substrates,
Wood substrates, cloth substrates (including natural fibers (silk, cotton, hemp), synthetic fibers (nylon, polyurethane, polyester) or recycled fibers (acetate, cupra, rayon, recycled polyester), etc.), leather substrates, rubber substrates, stainless steel・Still substrates, substrates with stainless steel foil, etc. can be used. Alternatively, the skin (epidermis, dermis) or subcutaneous tissue of animals such as humans may be used as the substrate. By using these substrates, it is possible to form transistors with good characteristics, transistors with low power consumption, and devices that are hard to break.
Heat resistance can be imparted, weight reduction, or thickness reduction can be achieved.

Note that the transistor can have various structures. Not limited to any particular configuration. For example, a multi-gate structure with two or more gate electrodes may be used. When the multi-gate structure is used, the channel regions are connected in series, resulting in a structure in which a plurality of transistors are connected in series. The multi-gate structure can reduce off-state current and improve reliability by increasing the withstand voltage of the transistor. Alternatively, due to the multi-gate structure, even if the voltage between the drain and source changes, the current between the drain and source does not change much when operating in the saturation region, and the slope of the voltage-current characteristics can be made flat. can. By utilizing the flat slope of the voltage/current characteristics, it is possible to realize an ideal current source circuit and an active load with a very high resistance value. As a result, a differential circuit or current mirror circuit with good characteristics can be realized. Alternatively, a structure in which gate electrodes are arranged above and below the channel may be used. Since the channel region is increased by arranging the gate electrodes above and below the channel, it is possible to increase the current value or reduce the S value by facilitating the formation of a depletion layer. When the gate electrodes are arranged above and below the channel, the configuration is such that a plurality of transistors are connected in parallel.

Alternatively, a structure in which the gate electrode is arranged above the channel region or a structure in which the gate electrode is arranged below the channel region may be used. Alternatively, a staggered structure or an inverted staggered structure may be used, the channel region may be divided into a plurality of regions, the channel regions may be connected in parallel, or the channel regions may be connected in series. good. again,
A source electrode or a drain electrode may overlap the channel region (or part thereof).
By forming a structure in which the source electrode and the drain electrode overlap with the channel region (or part thereof), it is possible to prevent the operation from becoming unstable due to accumulation of charge in part of the channel region. Also, an LDD region may be provided. By providing the LDD region, off-state current can be reduced, or the breakdown voltage of the transistor can be improved, thereby improving reliability. Alternatively, L
By providing the DD region, even if the voltage between the drain and the source changes when operating in the saturation region, the current between the drain and the source does not change much, and the slope of the voltage-current characteristics can be made flat. can.

Note that various types of transistors can be used and can be formed using various substrates. Therefore, all the circuits necessary for realizing a given function may be formed on the same substrate. For example, all circuits necessary for realizing a predetermined function may be formed using a glass substrate, a plastic substrate, a single crystal substrate, or an SOI substrate, and may be formed using various substrates. good too. All of the circuits required to achieve a given function are formed on the same substrate, which reduces costs by reducing the number of parts, or improves reliability by reducing the number of connections with circuit parts. can be planned. Alternatively, part of a circuit necessary for realizing a predetermined function is formed on one substrate, and another part of the circuit necessary for realizing a predetermined function is formed on another substrate. may be In other words, not all the circuits required for realizing a given function need to be formed using the same substrate. For example, part of the circuit required to achieve a given function is formed using transistors on a glass substrate, and another part of the circuit required to achieve a given function is formed on a single crystal substrate. An IC chip formed on the monocrystalline substrate and configured with transistors may be connected to the glass substrate by COG (Chip On Glass), and the IC chip may be arranged on the glass substrate. Alternatively, the IC chip is TAB (T
Ape Automated Bonding) or a printed circuit board may be used to connect to the glass substrate. Since part of the circuit is formed on the same substrate in this way, the cost can be reduced by reducing the number of parts, or the reliability can be improved by reducing the number of connections with circuit parts. In addition, circuits in areas where the drive voltage is high and in areas where the drive frequency is high consume a lot of power. An increase in power consumption can be prevented by forming a circuit for that portion in advance and using an IC chip configured with that circuit.

Note that one pixel indicates one element whose brightness can be controlled. Therefore, as an example, one pixel indicates one color element, and the single color element expresses brightness.
Therefore, at that time, in the case of a color display device consisting of R (red), G (green) and B (blue) color elements, the minimum unit of an image is an R pixel, a G pixel and a B pixel. It shall consist of three pixels. Note that the color elements are not limited to three colors, three or more colors may be used, and colors other than RGB may be used. For example, it may be RGBW (where W is white) by adding white. Also, R
One or more colors such as yellow, cyan, magenta, emerald green, and vermilion may be added to GB. Also, for example, a color similar to at least one color in RGB is defined as RGB
may be added to For example, it may be R, G, B1, and B2. Both B1 and B2 are blue, but have slightly different frequencies. Similarly, R1, R2, G, and B may be used. By using such color elements, a more realistic display can be achieved. Alternatively, power consumption can be reduced by using such color elements. again,
As another example, when controlling brightness using multiple regions for one color element,
One pixel may correspond to one area. Therefore, as an example, when area gradation is performed or when sub-pixels are provided, each color element has a plurality of regions for controlling brightness, and gradation is expressed by the entire region. However, one pixel may correspond to one region whose brightness is controlled. Therefore, in that case, one color element is composed of a plurality of pixels. Alternatively, even if one color element has a plurality of areas for controlling brightness, they may be grouped together and one color element may be defined as one pixel. Therefore, in that case, one color element is composed of one pixel. Further, when the brightness of one color element is controlled using a plurality of areas, the size of the area contributing to display may differ depending on the pixel. In addition, the viewing angle may be widened by slightly different signals supplied to each of the plurality of brightness control regions for each color element. i.e. 1
For one color element, the potentials of pixel electrodes in a plurality of regions may be different. As a result, the voltage applied to the liquid crystal molecules is different for each pixel electrode. Therefore, the viewing angle can be widened.

Note that when one pixel (for three colors) is explicitly described, it is assumed that three pixels of R, G, and B are considered to be one pixel. When one pixel (for one color) is explicitly described, it is assumed that, when one color element has a plurality of areas, they are collectively considered as one pixel.

Note that in this document (specification, claims, drawings, etc.), pixels may be arranged (arranged) in a matrix. Here, "the pixels are arranged (arranged) in a matrix" includes the case where the pixels are arranged in a straight line in the vertical direction or the horizontal direction, and the case where the pixels are arranged in a jagged line. Thus, for example, three color elements (eg, R
GB) for full-color display, including a stripe arrangement and a delta arrangement of dots of three color elements. Furthermore, the case of Bayer arrangement is also included. Note that the color elements are not limited to three colors, and may be more than three colors. For example, there are RGBW (W is white), and one or more colors such as yellow, cyan, and magenta are added to RGB.
Also, the size of the display area may be different for each dot of the color element. As a result, power consumption can be reduced or the life of the display element can be extended.

Note that an active matrix system in which pixels have active elements or a passive matrix system in which pixels do not have active elements can be used.

In the active matrix system, not only transistors but also various active elements (active elements, nonlinear elements) can be used as active elements (active elements, nonlinear elements). For example, MIM (Metal Insulator Metal) and TFD (
Thin Film Diode) or the like can also be used. Since these elements require fewer manufacturing steps, the manufacturing cost can be reduced or the yield can be improved. Furthermore, since the size of the element is small, the aperture ratio can be improved, and low power consumption and high luminance can be achieved.

As a method other than the active matrix method, it is also possible to use a passive matrix method that does not use active elements (active elements, non-linear elements). Since active elements (active elements, non-linear elements) are not used, the number of manufacturing steps is small, and the manufacturing cost can be reduced or the yield can be improved. Moreover, since an active element (active element, nonlinear element) is not used, the aperture ratio can be improved, and low power consumption and high brightness can be achieved.

Note that a transistor is an element having at least three terminals including a gate, a drain, and a source, and has a channel region between the drain region and the source region. A current can flow through the Here, since the source and the drain change depending on the structure of the transistor, operating conditions, etc., it is difficult to define which is the source or the drain. Therefore, in this document (specification, claims, drawings, etc.), regions that function as sources and drains may not be called sources or drains. In that case, as an example, they may be referred to as a first terminal and a second terminal, respectively. Alternatively, they may be referred to as a first electrode and a second electrode, respectively. Alternatively, they may be referred to as a source region and a drain region.

A transistor may be a device having at least three terminals including a base, an emitter and a collector. In this case also, the emitter and collector are connected to the first terminal and the second terminal.
Sometimes referred to as a terminal.

Note that a gate means the whole including a gate electrode and a gate wiring (also referred to as a gate line, a gate signal line, a scanning line, a scanning signal line, etc.) or a part of them. A gate electrode refers to a portion of a conductive film that overlaps a semiconductor forming a channel region with a gate insulating film interposed therebetween. Note that part of the gate electrode is LDD (Lightly Dopped
ed Drain) region or the source region (or drain region) in some cases through the gate insulating film. A gate wiring is a wiring for connecting gate electrodes of transistors, a wiring for connecting gate electrodes of pixels, or a wiring for connecting a gate electrode and another wiring. say.

However, there are portions (regions, conductive films, wirings, etc.) that function both as gate electrodes and as gate wirings. Such a portion (region, conductive film, wiring, etc.) may be called a gate electrode or a gate wiring. In other words, there are regions where the gate electrode and the gate wiring cannot be clearly distinguished. For example, when a portion of a gate wiring that is extended and arranged overlaps a channel region, that portion (region, conductive film, wiring, etc.) functions as a gate wiring, but it also functions as a gate electrode. It is working. Therefore, such a portion (region, conductive film, wiring, etc.) may be called a gate electrode or a gate wiring.

A portion (region, conductive film, wiring, etc.) made of the same material as the gate electrode and connected to form the same island as the gate electrode may also be called the gate electrode. Similarly, a portion (region, conductive film, wiring, etc.) formed of the same material as the gate wiring and connected to form the same island as the gate wiring may also be referred to as the gate wiring. Strictly speaking, such portions (regions, conductive films, wirings, etc.) may not overlap with the channel region or have the function of connecting to another gate electrode. However, due to manufacturing specifications, etc., a portion (region, conductive film, wiring, etc.) that is formed of the same material as the gate electrode or gate wiring and forms the same island as the gate electrode or gate wiring. There is Therefore, such portions (regions, conductive films, wirings, etc.) may also be called gate electrodes or gate wirings.

Note that, for example, in a multi-gate transistor, one gate electrode and another gate electrode are often connected by a conductive film formed using the same material as the gate electrode. Such portions (regions, conductive films, wirings, etc.) are portions (regions, conductive films, wirings, etc.) for connecting gate electrodes, so they may be called gate wirings. can be regarded as one transistor, it may be called a gate electrode. In other words, a portion (region, conductive film, wiring, etc.) that is formed of the same material as the gate electrode or the gate wiring and that forms the same island as the gate electrode or the gate wiring is connected to the gate electrode or the gate wiring. You can call me Furthermore, for example, a conductive film in a portion that connects a gate electrode and a gate wiring and is formed of a material different from that of the gate electrode or the gate wiring may be called a gate electrode or a gate wiring. You can call it

Note that the gate terminal refers to a portion of the gate electrode (region, conductive film, wiring, etc.) or a portion of a portion electrically connected to the gate electrode (region, conductive film, wiring, etc.). .

Note that when a gate wiring, a gate line, a gate signal line, a scanning line, a scanning signal line, or the like is used, the gate of the transistor may not be connected to the wiring. In this case, the gate wiring, the gate line, the gate signal line, the scanning line, and the scanning signal line are wirings formed of the same layer as the transistor gates, wirings formed of the same material as the transistor gates, or the gates of the transistors. In some cases, it means a film-formed wiring. Examples include storage capacitor wiring, power supply wiring, and reference potential supply wiring.

Note that the source means the whole including the source region, the source electrode, and the source wiring (also referred to as a source line, a source signal line, a data line, a data signal line, etc.) or a part of them. A source region is a semiconductor region containing a large amount of P-type impurities (boron, gallium, etc.) or N-type impurities (phosphorus, arsenic, etc.). Therefore, a region containing a small amount of P-type impurity or N-type impurity, that is, a so-called LDD (Lightly Doped Drain) region is not included in the source region. A source electrode is a portion of a conductive layer formed of a material different from that of a source region and electrically connected to the source region. However, the source electrode may also be called a source electrode including the source region. A source wiring is a wiring for connecting source electrodes of transistors, a wiring for connecting source electrodes of pixels, or a wiring for connecting a source electrode and another wiring. say.

However, there are portions (regions, conductive films, wirings, etc.) that function both as source electrodes and as source wirings. Such a portion (region, conductive film, wiring, etc.) may be called a source electrode or a source wiring. In other words, there are regions where the source electrode and the source wiring cannot be clearly distinguished. For example, when a portion of a source wiring that is extended and arranged overlaps with a source region, that portion (region, conductive film, wiring, etc.) functions as a source wiring, but does not function as a source electrode. is also functioning. Therefore, such a portion (region, conductive film, wiring, etc.) may be called a source electrode or a source wiring.

Note that a portion (a region, a conductive film, a wiring, etc.) which is formed of the same material as the source electrode and which forms the same island as the source electrode and is connected to the source electrode, or a portion (region) which connects the source electrode to another source electrode. , a conductive film, a wiring, etc.) may also be called a source electrode. Furthermore, the portion overlapping with the source region may also be called a source electrode. Similarly, a region formed of the same material as the source wiring and connected by forming the same island as the source wiring may also be called a source wiring. Strictly speaking, such portions (regions, conductive films, wirings, etc.) may not have the function of connecting to another source electrode. However, there are portions (regions, conductive films, wirings, etc.) formed of the same material as the source electrode or the source wiring and connected to the source electrode or the source wiring due to manufacturing specifications and the like. Therefore, such portions (regions, conductive films, wirings, etc.) may also be called source electrodes or source wirings.

Note that, for example, a conductive film in a portion connecting a source electrode and a source wiring and formed of a material different from that of the source electrode or the source wiring may be called a source electrode or a source wiring. You can call it

Note that the source terminal refers to a portion of a source region, a source electrode, or a portion electrically connected to the source electrode (region, conductive film, wiring, or the like).

When referring to source wiring, source line, source signal line, data line, data signal line, etc.,
In some cases, the source (drain) of the transistor is not connected to the wiring. In this case, the source wiring, the source line, the source signal line, the data line, and the data signal line are wiring formed of the same layer as the source (drain) of the transistor, and wiring formed of the same material as the source (drain) of the transistor. Alternatively, it may mean a wiring formed at the same time as the source (drain) of a transistor. Examples include storage capacitor wiring, power supply wiring, and reference potential supply wiring.

Note that the drain is the same as the source.

Note that a semiconductor device is a device having a circuit including a semiconductor element (transistor, diode, thyristor, or the like). Furthermore, all devices that can function by utilizing semiconductor characteristics may be called semiconductor devices. Alternatively, devices comprising semiconductor materials are referred to as semiconductor devices.

The display elements include optical modulation elements, liquid crystal elements, light-emitting elements, EL elements (organic EL elements, inorganic EL elements, or EL elements containing organic and inorganic materials), electron-emitting elements, electrophoretic elements, discharge elements, and light reflection elements. device, optical diffractive device, digital micromirror device (DMD), and the like. However, it is not limited to this.

Note that a display device means a device having a display element. Note that the display device may include a plurality of pixels including display elements. Note that the display device may include a peripheral driving circuit that drives a plurality of pixels. Note that a peripheral driver circuit for driving a plurality of pixels may be formed on the same substrate as the plurality of pixels. The display device includes peripheral driving circuits arranged on a substrate by wire bonding, bumps, or the like, so-called chip-on-glass (COG)-connected IC chips, or TAB-connected IC chips. You can stay. The display device may include a flexible printed circuit (FPC) to which IC chips, resistive elements, capacitive elements, inductors, transistors, and the like are attached. The display device may include a printed wiring board (PWB) connected via a flexible printed circuit (FPC) or the like and having an IC chip, a resistive element, a capacitive element, an inductor, a transistor, and the like attached. Note that the display device may include an optical sheet such as a polarizing plate or a retardation plate. Note that the display device may include a lighting device, a housing, an audio input/output device, an optical sensor, and the like. Here, a lighting device such as a backlight unit may include a light guide plate, a prism sheet, a diffusion sheet, a reflection sheet, a light source (LED, cold cathode tube, etc.), a cooling device (water cooling type, air cooling type), and the like. good.

The lighting device is a device having a backlight unit, a light guide plate, a prism sheet, a diffusion sheet, a reflection sheet, a light source (LED, cold cathode tube, hot cathode tube, etc.), a cooling device, and the like.

Note that a light-emitting device is a device having a light-emitting element or the like. In the case where a light-emitting element is used as a display element, the light-emitting device is one specific example of the display device.

The reflecting device means a device having a light reflecting element, a light diffraction element, a light reflecting electrode, or the like.

Note that a liquid crystal display device refers to a display device having a liquid crystal element. Liquid crystal display devices include a direct-view type, a projection type, a transmission type, a reflection type, a transflective type, and the like.

Note that a driving device means a device having a semiconductor element, an electric circuit, or an electronic circuit. For example, a transistor that controls the input of a signal from a source signal line into a pixel (sometimes called a selection transistor or switching transistor), a transistor that supplies voltage or current to a pixel electrode, and a voltage or current to a light-emitting element is an example of a driving device. Furthermore, a circuit that supplies a signal to a gate signal line (sometimes called a gate driver, gate line driver circuit, etc.), a circuit that supplies a signal to a source signal line (sometimes called a source driver, a source line driver circuit, etc.) ) is an example of a drive device.

Note that the display device, the semiconductor device, the lighting device, the cooling device, the light-emitting device, the reflecting device, the driving device, and the like may overlap each other. For example, a display device may have a semiconductor device and a light emitting device. Alternatively, a semiconductor device may have a display and a driver.

When it is explicitly described that B is formed on A or B is formed on A, it is limited to B being formed on A in direct contact. not. A case where they are not in direct contact, that is, a case where another object intervenes between A and B shall be included. Here, A and B are objects (for example, devices, elements, circuits, wiring, electrodes, terminals, conductive films, layers,
etc.).

Therefore, for example, when it is explicitly stated that layer B is formed on layer A (or on layer A), layer B is formed on layer A and in direct contact therewith. and a case where another layer (for example, layer C or layer D) is formed in direct contact with layer A, and layer B is formed in direct contact thereon. In addition, another layer (for example, layer C, layer D, etc.) may be a single layer or multiple layers.

Furthermore, the same applies to the case where it is explicitly described that B is formed above A, and is not limited to B being in direct contact with A. It shall include the case where another object intervenes. Therefore, for example, when the layer B is formed above the layer A, the case where the layer B is formed directly on the layer A and the case where the layer B is formed directly on the layer A and another layer (for example, layer C, layer D, etc.) are formed, and layer B is formed in direct contact thereon. In addition, another layer (for example, layer C, layer D, etc.) may be a single layer or multiple layers.

In addition, when it is explicitly described that B is formed on A in direct contact, it includes the case where B is formed in direct contact on A, and there is another If there is an object intervening, it shall not be included.

It should be noted that the same applies to the case where B is under A or B is under A.

In addition, it is preferable to use the singular number for items explicitly described as the singular number.
However, it is not limited to this, and may be plural. Similarly, for those explicitly described as plural, the plural is preferred. However, it is not limited to this, and may be singular.

A wide viewing angle display can be realized by the present invention. In addition, a display device with excellent contrast can be obtained. Further, a display device with excellent display quality can be provided.
In addition, a display device which is not easily affected by noise and can perform clear display can be provided. Alternatively, it is possible to provide a display device whose display is less likely to deteriorate. Alternatively, a display device with excellent product life can be provided.

FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; 4A and 4B are diagrams for explaining an example of a display device having a pixel of the present invention; A diagram for explaining a configuration example of a pixel included in a display device of the present invention. FIG. 13 is a diagram for explaining one operation method of the pixel shown in FIG. 12; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; 4A and 4B are diagrams for explaining an example of a display device having a pixel of the present invention; FIG. 20 illustrates a signal line switching circuit included in the display device illustrated in FIG. 19; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; FIG. 4 is a diagram showing an example of a pixel configuration of the present invention; 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. FIG. 4 is a diagram showing an example of a pixel layout of a display device according to the present invention; 4A and 4B are diagrams for explaining a liquid crystal mode of a display device according to the present invention; FIG. 4A and 4B are diagrams for explaining a liquid crystal mode of a display device according to the present invention; FIG. 4A and 4B are diagrams for explaining a liquid crystal mode of a display device according to the present invention; FIG. 4A and 4B are diagrams for explaining a liquid crystal mode of a display device according to the present invention; FIG. 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. FIG. 4 is a diagram showing an example of peripheral structural members of a display device according to the present invention; FIG. 4 is a diagram showing an example of peripheral structural members of a display device according to the present invention; FIG. 4 is a diagram showing an example of peripheral structural members of a display device according to the present invention; FIG. 4 is a diagram showing an example of peripheral structural members of a display device according to the present invention; FIG. 2 is a diagram showing an example of a panel circuit configuration of a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; 4A and 4B illustrate an example of the structure of a transistor included in a display device according to the present invention; 4A and 4B illustrate an example of the structure of a transistor included in a display device according to the present invention; 4A and 4B illustrate an example of the structure of a transistor included in a display device according to the present invention; 4A and 4B illustrate an example of the structure of a transistor included in a display device according to the present invention; 4A and 4B illustrate an example of the structure of a transistor included in a display device according to the present invention; 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. 1A and 1B are diagrams showing a configuration example of a display device according to the present invention; FIG. 1A and 1B are diagrams showing an electronic device using a display device according to the present invention; FIG. 1A and 1B are diagrams showing an electronic device using a display device according to the present invention; FIG. 1A and 1B are diagrams showing an electronic device using a display device according to the present invention; FIG. 1A and 1B are diagrams showing an electronic device using a display device according to the present invention; FIG. 1A and 1B are diagrams showing an electronic device using a display device according to the present invention; FIG. 1A and 1B are diagrams showing an electronic device using a display device according to the present invention; FIG. 1A and 1B are diagrams showing an electronic device using a display device according to the present invention; FIG. 1A and 1B are diagrams showing an electronic device using a display device according to the present invention; FIG. 1A and 1B are diagrams showing an electronic device using a display device according to the present invention; FIG. FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; FIG. 10 is a diagram showing an example of a method for driving a display device according to the present invention; The figure explaining a prior art.

One embodiment of the present invention is described below. Those skilled in the art will readily appreciate, however, that the present invention may be embodied in many different forms and that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. be done. Therefore, it should not be construed as being limited to the contents described in this embodiment. In addition, in the configuration of the present invention described below, the same reference numerals are used in different drawings, and the description thereof is omitted.

(Embodiment 1)
A basic configuration of a pixel of the present invention will be described with reference to FIG. A pixel shown in FIG. , the first holding capacitor 131
and a second storage capacitor 132 . Also, the pixels are connected to the signal line 116 and the Cs line 119 . Note that each of the first liquid crystal element 121 and the second liquid crystal element 122 has a pixel electrode, a common electrode 118 , and liquid crystal controlled by the pixel electrode and the common electrode 118 .

In FIG. 1, the pixel electrode of the first liquid crystal element 121 is connected to the signal line 116 via the first switch 111 . Also, the pixel electrode of the first liquid crystal element 121 is connected to the second switch 1
12 and the pixel electrode of the second liquid crystal element 122 via the first resistor 114 . Assuming that a connection point between the first resistor 114 and the pixel electrode of the second liquid crystal element 122 is a node 142 , the node 142 is connected to the Cs line 119 via the third switch 113 and the second resistor 115 .
is connected with A node 141 is a connection point between the second switch 112 and a wiring to which the pixel electrode of the first liquid crystal element 121 and the first switch 111 are connected.

The on/off states of the first switch 111, the second switch 112, and the third switch 113 are controlled by a signal input to the scanning line 117 as shown in FIG. 2, for example.

An image signal corresponding to a video signal, that is, a potential corresponding to the gradation of a pixel is input to the signal line 116 .

Although the liquid crystal element exhibits a voltage holding characteristic, the holding ratio is not 100%. Therefore, in order to maintain the held voltage, the pixels shown in FIGS. A first holding capacitor 131 and a second holding capacitor 132 are provided corresponding to each of the liquid crystal elements 122 . Specifically, the pixel electrode of the first liquid crystal element 121 is connected to the Cs line 119 through the first storage capacitor 131, and the pixel electrode of the second liquid crystal element 122 is connected to the second storage capacitor 13.
2 to the Cs line 119 . Note that the voltage holding characteristics of the liquid crystal element depend on the liquid crystal material, impurities mixed therein, the size of the pixel, and the like. It doesn't have to be. Further, for example, when the second liquid crystal element 122 contributes less to display than the first liquid crystal element 121, a second storage capacitor provided for the second liquid crystal element 122 which contributes less to display 132 may be omitted.

Also, in FIG. 1, the node 141 is connected to the node 142 through the second switch 112 and the first resistor 114 in this order. Also good. Also, the node 142 is connected to the second resistor 115 and the third switch 11
3 in turn may be connected to the Cs line 119 . Of course, as shown in FIG. 27, in the second switch 112 and the first resistor 114, and in the third switch 113 and the second resistor 115, the connection relationship between the switches and the resistors may be reversed.

Further, each of the first liquid crystal element 121 and the second liquid crystal element 122 may be composed of a plurality of liquid crystal elements. Similarly, each of the first holding capacitor 131 and the second holding capacitor 132 may be composed of a plurality of holding capacitors. For example, the first liquid crystal element 1 shown in FIG.
21, each of the second liquid crystal elements 122, from the two liquid crystal elements, the first storage capacitor 131, the second
is composed of two holding capacitors.

Next, the operation of the pixel described above will be described with reference to FIG. First switch 111, second
The on/off of the switch 112 and the third switch 113 are controlled by inputting a signal to the scanning line 117. Here, the scanning line 117 is set to High level (hereinafter referred to as H level).
A case in which the first switch 111, the second switch 112 and the third switch 113 are turned on by inputting is explained. In this case, these switches are turned off when a Low level (hereinafter referred to as L level) is input to the scanning line 117 .

First, when the scanning line 117 becomes H level, the first switch 111 and the second switch 112 are turned on.
and the third switch 113 are turned on, and the potential corresponding to the pixel gradation input from the signal line 116 is applied to the pixel electrode of the first liquid crystal element 121 and the first storage capacitor 131 through the first switch 111 . is supplied to the first electrode of the Further, this potential is supplied to the pixel electrode of the second liquid crystal element 122 and the first electrode of the second storage capacitor 132 through the second switch 112 and the first resistor 114 . Note that the potential supplied to the pixel electrode of the second liquid crystal element 122 and the first electrode of the second storage capacitor 132 is the same as the potential of the node 142, which is the potential difference between the node 141 and the Cs line 119. and the resistance values in the first resistor 114 and the second resistor 115 . That is, the signal line 11 is connected to the pixel electrode of the second liquid crystal element 122 .
A potential corresponding to the gradation of the pixel input from 6 is resistance-divided by the first resistor 114 and the second resistor 115 and supplied. Note that Vsig is the potential corresponding to the gradation of the pixel input from the signal line 116, R1 is the resistance value of the first resistor 114, R2 is the resistance value of the second resistor 115, and the potential supplied to the Cs line 119. is Vcs, the potential of node 141 is Vsig
, the potential of node 142 is Vcs+(Vsig−Vcs)×R2/(R1+R2).

Further, the potential corresponding to the gradation input from the signal line 116 and Cs
The potential difference between the potential of the line 119 and the potential of the Cs line 1 is divided by resistance in the second holding capacitor 132 .
The potential difference with the potential of 19 is held.

Next, L level is input to the scanning line 117 . Then, the first switch 111, the second switch 112, and the third switch 113 are turned off, and the signal line 116 and the first liquid crystal element 121 are turned off.
and the second liquid crystal element 122 are electrically isolated from each other. However, the potential difference between the potential corresponding to the gradation input from the signal line 116 and the potential of the Cs line 119 is held in the first holding capacitor 131, and the second holding capacitor 132 holds the potential divided by resistance. A potential difference from the potential of the Cs line 119 is held. Therefore, the pixel electrode of the first liquid crystal element 121 can maintain a potential corresponding to the gradation of the pixel input from the signal line 116, and the potential of the pixel electrode of the second liquid crystal element 122 is divided by resistance. can be maintained.

In this manner, the gradation of a pixel is expressed using the potential difference, that is, the voltage held between the first liquid crystal element 121 and the second liquid crystal element 122 . First liquid crystal element 121 and second liquid crystal element 12
2, different voltages are applied, so that the liquid crystal of each liquid crystal element can exhibit different orientations. Therefore, viewing angle characteristics can be improved. Note that since the gradation expressed by a pixel is determined by the orientation of liquid crystals in each of the first liquid crystal element 121 and the second liquid crystal element 122 in the pixel, the potential supplied from the signal line 116 takes these factors into account. must be determined by Thus, since the alignment of the first liquid crystal element 121 and the second liquid crystal element 122 can be controlled by one signal line 116, the aperture ratio of the pixel can be increased.

By the way, in such a pixel configuration, the second liquid crystal element 122 is the same as the first liquid crystal element 1
21, the applied voltage is smaller. Therefore, the second resistor 115 is replaced with the first resistor 1
If it is too much smaller than 14, the voltage applied to the second liquid crystal element 122 becomes smaller than the threshold voltage of the liquid crystal, and the liquid crystal of the second liquid crystal element 122 may not be driven. Therefore,
The resistance value R2 of the second resistor 115 is greater than the resistance value R1 of the first resistor 114 (R2>R
1) is preferred. Of course, the relationship between the resistance values is not limited to this, and it is sufficient if the liquid crystals of the first liquid crystal element 121 and the second liquid crystal element 122 are driven and the gradation can be expressed using both liquid crystals. Note that the threshold voltage of liquid crystal refers to a critical value of voltage required to drive the liquid crystal.

Also, the resistance values of the first resistor 114 and the second resistor 115 are large, and the second switch 112
Even if the third switch 113 is not provided, these switches are particularly provided if the potentials of the nodes 141 and 142 when they are input from the signal line 116 can be maintained even after the first switch 111 is turned off. It doesn't have to be. For example, if the resistance value of the first resistor 114 is large, the second switch 112 provided between the nodes 141 and 142 may be omitted, and if the resistance value of the second resistor 115 is large, the node 142 may be omitted. and the Cs line 119 may be omitted. Of course, if both are large, the second switch 112 and the third switch 113 can be omitted.

Note that various modes can be used for the first switch 111, the second switch 112, and the third switch 113, and an electrical switch, a mechanical switch, or the like can be applied. . In other words, it is not limited to a specific one as long as it can control the flow of current. For example, a transistor, a diode, or a logic circuit combining these may be used.

Also, the first resistor 114 and the second resistor 115 can be realized using various elements. In other words, it is not limited to a resistive element because it can be realized by using an element that causes a voltage drop when a current flows. For example, a transistor, diode, capacitor, inductor, or the like can be used. Diodes include PN diodes, PIN diodes,
MIM diodes, Schottky diodes, diode-connected transistors, and the like can be used. A silicon layer, a silicon layer lightly doped with impurities (same concentration as LDD), a silicon layer heavily doped with impurities (same concentration as the source region and drain region), ITO or IZO can be used as the resistance element. For example, an oxide semiconductor such as an oxide semiconductor, a conductor with a longer wiring length, or the like can be used. Note that although the case where the switch and the resistor are provided separately is described in FIGS. 1 to 3, the present invention is not limited to this. A single element may be used to implement both the switch and the resistor.

As shown in FIG. 4, a second transistor 212 and a third transistor 213 are used for the second switch 112 and the third switch 113 in FIG. 2, respectively. , the first resistor 114 and the second resistor 115 may be realized, and these resistors may be omitted. In addition, as described above, the second resistor 11
5 is preferably larger than the resistance value R1 of the first resistor 114 (R2>R1). A higher resistance is preferred. Therefore, the second transistor 212
The channel width of the third transistor 213 is W2, the channel length is L2, and the channel width of the third transistor 213 is W3.
, and a channel length of L3, it is preferable to use transistors satisfying W2/L2>W3/L3. However, it is not limited to this relationship. Of course, the pixel configuration is not limited to this. For example, as shown in FIG.
12, the third transistor 213 may be used without omitting the resistor.

A transistor (here, referred to as a first transistor) is used as the first switch 111 .
is used, it is preferable that the on-resistance of the first transistor is as low as possible. 6, the first transistor 2 is connected to the first switch 111 in the configuration shown in FIG.
11 is used. Note that when the first transistor 211 is compared with the second transistor 212 and the third transistor 213, W1/L1>W2/L2>W
It is preferable to use a transistor with 3/L3. However, it is not limited to this.

In order to increase the on-resistance of the third transistor 213, a multi-gate transistor in which two transistors are connected in series as the transistor 313 as shown in FIG. 7 may be used. Note that although FIG. 7 shows the case where two transistors are connected in series, the number of transistors connected in series is not particularly limited.

Note that the channel length L of the transistor 313 acts as the sum of the channel lengths of the two transistors connected in series when the channel widths W of the two transistors are the same. Therefore, W/L tends to be smaller, and the on-resistance can be increased. Therefore, by using a multi-gate transistor, the on-resistance of the transistor 313 can be easily increased compared to the on-resistance of the second transistor 212 .

Further, for example, when the on-resistance of the third transistor 213 is much smaller than that of the second transistor 212, the voltage applied to the second liquid crystal element 122 is
8, a diode-connected transistor 414 may be provided in series with the third transistor 213 as a resistor as shown in FIG. The diode-connected transistor 414 allows the second storage capacitor 132 to hold a voltage at least equal to or higher than the threshold voltage of the transistor 414 .
Therefore, by using the diode-connected transistor 414, the second liquid crystal element 1
22, the voltage applied to the second liquid crystal element 122 can be increased more reliably.
can drive the liquid crystal of Diodes are non-linear and have a higher resistance in a low voltage region, so they are particularly effective in this case. Of course, it is also possible to use resistors. Note that the illustration here assumes that the potential corresponding to the grayscale input from the signal line 116 is positive, an N-channel transistor is used as the transistor 414 , and its drain electrode A connected example is shown. Of course, a P-channel transistor can also be used as the transistor 414 . However, in this case, the source electrode is connected to the third transistor 213 .

In addition, in a normal liquid crystal display device, positive and negative image signals, that is, positive and negative image signals are alternately supplied through a signal line every frame period around the potential of a common electrode. In such a case, the image signal is a signal that is positive and negative with respect to the potential supplied to the Cs line. Therefore, the potential of the Cs line 119 may be changed depending on whether a positive image signal is input or a negative image signal is input. That is, the potential of the Cs line 119 should be lower when a negative signal is input than when a positive signal is input. Thereby, it is possible to appropriately supply a voltage to each pixel electrode. The pixels shown in FIG. 8 may be configured as shown in FIG. 9 so as to be compatible with both positive and negative image signals. The pixel shown in FIG. 9 has a configuration in which a diode-connected transistor 614 is further provided in parallel with the diode-connected transistor 414 in FIG. Note that when these transistors have the same conductivity type, the transistors 414 and 614 are connected so that their drain electrodes are different from each other. With such a configuration, the Cs line 1
19 and the potential supplied from the signal line 116 are reversed, the second holding capacitor 13
2 can hold a voltage at least equal to or higher than the threshold voltage of transistor 414 or transistor 614 . Therefore, the voltage applied to the second liquid crystal element 122 can be increased, and the liquid crystal included in the second liquid crystal element 122 can be driven more reliably. Note that the pixel configuration shown in FIG. 9 may be used even when such a driving method is not used.

In this specification, a positive voltage is applied to the liquid crystal element when the potential of the pixel electrode is higher than that of the common electrode, and a negative voltage is applied to the liquid crystal element when the potential of the common electrode is higher than that of the pixel electrode. It is written that it was done. An image signal input from the signal line when a positive voltage is applied to the liquid crystal element is defined as a positive signal, and an image signal input via the signal line when a negative voltage is applied is defined as a negative signal. Notation as a sex signal.

In this specification, the common electrode 118 and the Cs line 119 may be supplied with different potentials, but may be supplied with the same potential. Further, as shown in FIG. 10, the common electrode 1
18 and the Cs line 119 may be shared. Note that FIG. 10 shows a case where the common electrode 118 and the Cs line 119 in FIG. 1 are shared using the wiring 100 .

Next, a display device having the pixel of the present invention described above will be described with reference to FIG.

The display device includes a signal line driver circuit 511, a scanning line driver circuit 512, and a pixel portion 513.
The pixel portion 513 includes a plurality of signal lines S1 to Sm extending in the column direction from the signal line driving circuit 511, scanning lines G1 to Gn extending in the row direction from the scanning line driving circuit 512, and It has a plurality of pixels 514 arranged in a matrix corresponding to the Cs lines Cs_1 to Cs_n and the signal lines S1 to Sm. Each pixel 514 is connected to a signal line Sj (signal lines S1 to S
m), scanning line Gi (any one of scanning lines G1 to Gn), and Cs line Cs_i.

The signal line Sj, scanning line Gi, and Cs line Cs_i correspond to the signal line 116, scanning line 117, and Cs line 119 in FIG. 2, respectively. A common electrode 118 in FIG.
4 are connected in common or electrically connected, and supplied with the same potential. When the Cs line 119 and the common electrode 118 are to be at the same potential, these may be electrically connected using conductive fine particles, wiring, or the like outside the pixel portion 513 .

A row of pixels to be operated by a signal input from the scanning line driving circuit 512 to the scanning line Gi is selected, and each pixel belonging to the selected row is supplied with signals from the signal line driving circuit 511 via the signal lines S1 to Sm. supplies a potential corresponding to the gradation of The potential supplied from the signal line Sj allows the pixel to express gradation as described above.

In order to suppress deterioration of the liquid crystal material and display unevenness such as flickering, the polarity of the voltage applied to the pixel electrode is inverted with respect to the potential of the common electrode (common potential) in the liquid crystal element at regular intervals. It is preferable to use an inversion drive in which the voltage is shifted and driven. Examples of inversion drive include frame inversion drive, source line inversion drive, gate line inversion drive, dot inversion drive, and the like.

Frame inversion driving is a driving method in which the polarity of the voltage applied to the liquid crystal element is inverted every frame period. Note that one frame period corresponds to a period in which an image of one pixel is displayed, and the period is not particularly limited. It is preferable to:

Furthermore, it is desirable to shorten the cycle and increase the frequency to reduce image blurring in moving images. Desirably, the period is 1/120 second or less (frequency is 120 Hz or more). More preferably, the cycle is 1/180 sec or less (frequency is 180 Hz or more). When increasing the frame frequency in this way, it is necessary to interpolate the image data when it does not match the frame frequency of the original image data. In this case, the image data can be displayed at a high frame frequency by interpolating the image data using motion vectors. As described above, the motion of the image is displayed smoothly, and display with little afterimage can be performed.

Further, source line inversion driving means inverting the polarity of the voltage applied to the liquid crystal elements belonging to the pixels connected to the same signal line with respect to the liquid crystal elements belonging to the pixels connected to the adjacent signal line. This driving method performs frame inversion for each pixel. On the other hand, in gate line inversion driving, the polarity of the voltage applied to the liquid crystal elements belonging to the pixels connected to the same scanning line is
In this driving method, the liquid crystal elements belonging to pixels connected to adjacent scanning lines are inverted, and each pixel is subjected to frame inversion. Dot inversion driving is a driving method for inverting the polarity of a voltage applied to a liquid crystal element between adjacent pixels, and is a driving method combining source line inversion driving and gate line inversion driving.

By the way, the above frame inversion drive, source line inversion drive, gate line inversion drive,
When dot inversion driving or the like is adopted, the width of the potential required for the image signal written to the signal line is doubled compared to when inversion driving is not performed. Therefore, in order to solve this problem, in the case of frame inversion driving or gate line inversion driving, common inversion driving for inverting the potential of the common electrode may be adopted.

Common inversion driving is a driving method in which the potential of the common electrode is changed in synchronization with the inversion of the polarity applied to the liquid crystal element. Width can be reduced. In this case, it is preferable that the common electrode 118 and the Cs lines 119 (Cs lines Cs_1 to Cs_n in FIG. 11) are electrically connected. Since the same signal is input to the common electrode 118 and the Cs line 119, more appropriate display can be achieved.

Next, FIG. 12 shows a configuration example of a pixel that can implement dot inversion driving. In FIG. 12, four pixels are extracted and described, and each pixel has the configuration shown in FIG. In the figure, signal lines 116_1 and 116_2 are the signal line 116 in FIG.
_1, 117_2 to scanning line 117, Cs lines 119_1, 119_2, 719_1, 71
9_2 corresponds to the Cs line 119 . Signals of different polarities are input to the signal lines 116_1 and 116_2. In accordance with the polarity, pixels belonging to the same row have different C values from adjacent pixels.
The s-lines, ie, Cs-lines 119_1, 719_2 or 119_1, 719_2 are used to supply potentials different from adjacent pixels as shown in FIG. Dot inversion driving may be performed by driving as shown in FIG.

Note that |Vsig(0)| is the signal for displaying black in the case of normally black and the signal for displaying white in the case of normally white, and the potential of the common electrode is Vcom.
Then, when a positive signal is supplied to the pixel from the signal line, Vsig (
0) It suffices if a potential of +Vcom or less is supplied to the Cs line. On the other hand, when a negative signal is supplied to the pixel, a potential of -Vsig(0)+Vcom or more and Vcom or less may be supplied to the Cs line.

Note that when a positive signal is supplied to the pixel, Vcom+α or more Vsig(0)+V
com, or -Vsig(0)+Vc when a negative signal is supplied to the pixel.
A potential of om or more and Vcom-α or less is preferably supplied to the Cs line. where α is V
sig/2. Furthermore, more preferably, when a positive signal is supplied to the pixel, V
The potential of sig(0)+Vcom is -Vsig when a negative signal is supplied to the pixel.
A potential of (0)+Vcom is preferably supplied.

Thus, the potential of the Cs line is changed to Vsig (0
)+Vcom and −Vsig(0)+Vcom when a negative signal is supplied, the voltage applied to the second liquid crystal element 122 can be increased, and the second liquid crystal Control of the element 122 can be facilitated.

Note that the potential of the Cs line is set to Vsig(0)+Vco when a positive signal is supplied to the pixel.
If the potential is higher than m, a voltage higher than Vsig(0) is always applied to the liquid crystal.
Black cannot be displayed when normally black, and white cannot be displayed when normally white. When a negative signal is supplied to the pixel, -Vsig(0)+
When a potential lower than Vcom is supplied to the Cs line, it becomes impossible to display black when normally black and white when normally white, as in the case of a positive polarity signal.

Note that in FIG. 13, the potential of Vcom is 0 V, and the potential of Cs is 0 V when a positive signal is supplied to the pixel.
The potential of the line is Vsig(0), and the potential of the Cs line is -V when a negative signal is supplied to the pixel.
A case of sig(0) is described.

Note that the inversion driving method is not limited to the above.

Although the above-described FIGS. 1 to 12 show the case where two liquid crystal elements are provided in one pixel, the number of liquid crystal elements included in the pixel is not particularly limited. FIG. 14 shows a case where one pixel includes three liquid crystal elements. A pixel illustrated in FIG. 14 includes a fourth transistor 814, a third liquid crystal element 823, and a third storage capacitor 833 in addition to the structure of the pixel illustrated in FIG. In FIG. 14, the pixel electrode of the third liquid crystal element 823 is connected to the signal line 116 through the second transistor 212 and the first switch 111 . Also, the third liquid crystal element 8
23 and the second transistor 212 is a node 800 , the node 800 is connected to the node 142 through the fourth transistor 814 . Note that the gate electrode of the fourth transistor 814 is connected to the scan line 117 like the second transistor 212 and the third transistor 213 . Also, the node 800 is connected to the Cs line 119 via the third holding capacitor 833 . Thus, in FIG. 14, transistor 8
14 , a liquid crystal element 823 , and a storage capacitor 833 are provided between the second transistor 212 and the node 142 . Note that when increasing the number of liquid crystal elements included in a pixel, the number of units 801 may be increased, for example. Of course, it is not limited to this.

Further, one pixel may have a plurality of pixel configurations described above. FIG. 15 shows a configuration example of such a pixel. The pixel shown in FIG. 15 has two sub-pixels 900a and 900b, and these sub-pixels are used to express the gradation of one pixel. In FIG. 15, each sub-pixel has the pixel configuration shown in FIG. However, the signal lines 116 and scanning lines 117 connected to the sub-pixels 900a and 900b are shared between the sub-pixels. note that,
Cs lines 119a and 119b in the figure correspond to the Cs line 119 in FIG. Each of the Cs lines 119 connected to the sub-pixels 900a, 900b, ie Cs lines 119a, 119b
By supplying different potentials to the sub-pixels, different voltages can be applied to the liquid crystal elements belonging to the respective sub-pixels. In this way, it is possible to further improve the viewing angle by utilizing the difference in alignment of the liquid crystal in each sub-pixel.

Also, as shown in FIG. 15, the case where the signal line 116 and the scanning line 117 are used as common wiring between sub-pixels is shown, but as shown in FIG.
It may be shared between 000a and 1000b. Also, as shown in FIG. 17, only the signal line 116 may be shared between the sub-pixels 1100a and 1100b, and the gradation of one pixel may be expressed using these sub-pixels. Note that the wiring used in common between sub-pixels is not limited to the above.
The s-line 119 may be used, or two or more lines may be shared as shown in FIG. Signal lines 116a and 116b in FIG. 16 or 17 correspond to signal line 116 in FIG. 4, scanning lines 117a and 117b correspond to scanning line 117 in FIG.
corresponds to the Cs line 119 in FIG.

15 to 17 show the case where one pixel is composed of sub-pixels having the same configuration, but the sub-pixels may have different configurations.

As described above, the viewing angle characteristic can be improved by the present invention. Furthermore, since the configuration enables driving without causing a decrease in contrast, it is possible to provide a liquid crystal display device with higher display quality.

Note that in this embodiment, the first switch 111 and the second switch 112 shown in FIG.
and the third switch 113 are controlled at the same time, each switch may be controlled separately. For example, in addition to the scanning line 117 shown in FIG. 2, other scanning lines may be used for separate control. Also, some of the switches may be controlled simultaneously while the remaining switches are controlled separately. Also, in the above, the resistors and switches may be replaced with capacitors.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each drawing of this embodiment may be applied, combined or replaced with the content (may be part of) described in the drawing of another embodiment. etc. can be done freely. Furthermore, in the drawings of this embodiment, more drawings can be configured by combining each part with another embodiment.

In addition, the present embodiment is an example of a case where the content (or part of it) described in another embodiment is embodied, an example of a slightly modified case, an example of a partially changed case, and an improved case. An example of the case,
An example of detailed description, an example of application, and an example of related parts are shown. Therefore, the contents described in other embodiments can be freely applied, combined, or replaced with this embodiment.

(Embodiment 2)
In this embodiment, FIG. 18 shows a configuration different from that of the first embodiment. In Embodiment 1, the potential applied to the pixel electrodes of the first liquid crystal element and the second liquid crystal element is determined by resistance division between the signal line and the Cs line, but the Cs line does not necessarily have to be applied. . An example thereof is shown in this embodiment.

A pixel 1200 shown in FIG. 18 includes a switch 111, a transistor 212, a transistor 2
13 , a first liquid crystal element 121 , a second liquid crystal element 122 , a first holding capacitor 131 and a second holding capacitor 132 . Note that the pixel 1200 is connected to the signal line 116 , the scanning line 117 , the Cs line 119 and the potential supply line 1219 . That is, the pixel 1200 is similar to that of the first embodiment.
4, one electrode of the transistor 213 is not the Cs line 119,
It is configured to be connected to the potential supply line 1219 . Of course, reference numerals indicating the same items are commonly used among the drawings, and descriptions thereof are omitted. Note that four pixels 1200 are extracted and described in FIG.

In the pixel 1200 shown in FIG. 18 as well, frame inversion driving, source line inversion driving, gate line inversion driving, and dot inversion driving can be appropriately selected and used. Note that the potential supply line 1219 may be supplied with a constant potential during one frame period, depending on the driving method. It may be changed for each period in which the potential corresponding to the key is input.

Further, a transistor can be used as the switch 111 in FIG. 18 as described in Embodiment 1, and each of the transistors 212 and 213 can be replaced with a switch and a resistor. In addition, the pixel 1200 in FIG. 18 can be combined with the items described in Embodiment 1 as appropriate.

Further, it is also possible to input an image signal to the potential supply line 1219 shown in FIG. 18 and to make the potential supply line 1219 and the signal line 116 function in reverse. In this way, by changing the wiring for inputting the image signal, that is, the potential corresponding to the gradation of the pixel, one liquid crystal element, for example, the first liquid crystal element 121 is applied more than the other, for example, the second liquid crystal element 122 . It can prevent the voltage on the Therefore, deterioration of the liquid crystal element can be delayed.

A display device having such pixels will be described with reference to FIG. The display device includes a signal line driver circuit 511, a signal line switching circuit 1300, a scanning line driver circuit 512, and a pixel portion 51.
3, and the signal line switching circuit 1300 is used to switch wiring for supplying image signals.
Note that the display device shown in FIG. 19 is provided with a signal line switching circuit 1300 in addition to the structure of the display device shown in FIG. Note that the signal line switching circuit 1300 is included in the pixel portion 513 .
A plurality of wirings 1316 and 1319 extending in the column direction from the scanning line driving circuit 512, scanning lines G1 to Gn and Cs lines Cs_1 to Cs_n extending in the row direction from the scanning line driving circuit 512
, and a plurality of pixels 1200 arranged in a matrix corresponding to the wiring 1316 . Each pixel 1200 includes wiring 1316, wiring 1319, scanning lines Gi (scanning lines G1 to
Gn), connected to the Cs line Cs_i. Note that the wiring 1316 and the wiring 1319 are connected via the signal line switching circuit 1300 to the signal line Sj (signal line S1
to Sm), and is connected to any of the potential supply lines Sj_2. Of course, when only signal lines are used as wiring for supplying image signals, the signal line switching circuit 1300
is unnecessary.

The signal line switching circuit 1300 will be described with reference to FIG. Signal line switching circuit 1
Reference numeral 300 denotes m units 140 corresponding to the pixels 1200 in the column direction of the pixel portion.
0, an inverter 1401 , a wiring 1402 , and a wiring 1403 connected to the wiring 1402 via the inverter 1401 . Each unit 1400 includes a transistor 1404
, a transistor 1405, a transistor 1406, and a transistor 1407, and a wiring 1
402, wiring 1403, signal line Sj, potential supply line Sj_2, wiring 1316, wiring 1319
is connected with The signal line Sj_2 is connected to the wiring 1316 through the transistor 1404 and the wiring 1319 through the transistor 1405, and the potential supply line Sj_2 is connected to the wiring 1319 through the transistor 1406 and the wiring 1316 through the transistor 1407.
is connected with Note that the transistors 1405 and 1407 are connected to the wiring 140
2, the transistors 1404 and 1406 are controlled to be on/off by the wiring 1403 .

A signal synchronized with one scanning line period or one frame period is input to the wiring 1402,
An inverted signal of the signal input to the wiring 1402 through the inverter 1401 is input to the wiring 1430 . Therefore, when the transistors 1405 and 1407 are off, the transistors 1404 and 1406 are on, and when the transistors 1405 and 1407 are on, the transistor 1 is on.
404 and transistor 1406 are off. In this way, it is possible to select to which of the wiring 1316 and the wiring 1319 the signal line Sj and the potential supply line Sj_2 are connected. Note that a signal to be input to the wiring 1402 may be selected as appropriate by an inversion driving method.

Also, the Cs line 119 may be replaced by the scanning line 117 in the previous row as shown in FIG. Here, the case where the Cs line 119 and the scanning line 117 in the previous row are shared is shown.
Any constant potential can be supplied to the second electrodes of the first holding capacitor 131 and the second holding capacitor 132 without being limited to the Cs line 119 . Note that during one frame period, the first
Although it is preferable that the second electrodes of the holding capacitor 131 and the second holding capacitor 132 do not fluctuate,
As shown in FIG. 21, it can be used immediately before the next frame period because it does not greatly affect the alignment of the liquid crystals of the first liquid crystal element 121 and the second liquid crystal element 122 . By sharing the wiring with the preceding row in this manner, the number of wirings in one pixel can be reduced, and the aperture ratio can be improved.

In the pixel configuration as described above, as in Embodiment 1, the gradation expressed by the pixel is determined by the liquid crystal orientation of each of the first liquid crystal element 121 and the second liquid crystal element 122 in the pixel. Therefore, the viewing angle can be improved. Furthermore, since the configuration enables driving without causing a decrease in contrast, it is possible to provide a liquid crystal display device with higher display quality.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each drawing of this embodiment may be applied, combined or replaced with the content (may be part of) described in the drawing of another embodiment. etc. can be done freely. Furthermore, in the drawings of this embodiment, more drawings can be configured by combining each part with another embodiment.

In addition, the present embodiment is an example of a case where the content (or part of it) described in another embodiment is embodied, an example of a slightly modified case, an example of a partially changed case, and an improved case. An example of the case,
An example of detailed description, an example of application, and an example of related parts are shown. Therefore, the contents described in other embodiments can be freely applied, combined, or replaced with this embodiment.

(Embodiment 3)
In this embodiment, an example of a pixel configuration different from those in Embodiments 1 and 2 will be described. Figure 2
2 includes a switch 111, a transistor 212, a transistor 213, a first liquid crystal element 121, a second liquid crystal element 122, a first holding capacitor 131, a second holding capacitor 132, and a third holding capacitor 1601. have. 22 is connected to the signal line 116, the scanning line 117, and the Cs line 119, and the voltage between the node 142 and one electrode of the transistor 213 in the pixel in FIG. A third holding capacitor 1601 is provided in the . Reference numerals indicating the same elements as those in FIG. 4 are commonly used in the drawings, and descriptions thereof are omitted.

The pixel shown in FIG. 22 can also be operated in the same manner as the pixel shown in FIG. However, by providing the third storage capacitor 1601, it takes time to reach the potential corresponding to the gradation to be supplied to the pixel electrode of the second liquid crystal element 122. FIG. Therefore, the first liquid crystal element 1
By delaying the response of the liquid crystal of the second liquid crystal element 122 to which the voltage applied is lower than that of 21, the viewing angle can be further improved. Even in this case, the gradation expressed by a pixel is determined by the alignment of the liquid crystal of each of the first liquid crystal element 121 and the second liquid crystal element 122 in the pixel. be determined in consideration of

Also, as shown in FIG.
2 may be provided. Also in FIG. 23, the pixel can be operated in the same manner as the pixel shown in FIG. As with the pixel shown in FIG. 22, it takes time until the pixel electrode of the second liquid crystal element 122 reaches the potential corresponding to the gradation to be supplied. By using this, the viewing angle can be further improved. In this case, considering that the voltage applied to the second liquid crystal element 122 is determined by the capacity division with the third holding capacitor 1701, the signal line 1
16 must be determined.

In the pixel configuration as described above, as in Embodiment 1, the gradation expressed by the pixel is determined by the liquid crystal orientation of each of the first liquid crystal element 121 and the second liquid crystal element 122 in the pixel. Therefore, the viewing angle can be improved. Furthermore, since the configuration enables driving without causing a decrease in contrast, it is possible to provide a liquid crystal display device with higher display quality.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each drawing of this embodiment may be applied, combined or replaced with the content (may be part of) described in the drawing of another embodiment. etc. can be done freely. Furthermore, in the drawings of this embodiment, more drawings can be configured by combining each part with another embodiment.

In addition, the present embodiment is an example of a case where the content (or part of it) described in another embodiment is embodied, an example of a slightly modified case, an example of a partially changed case, and an improved case. An example of the case,
An example of detailed description, an example of application, and an example of related parts are shown. Therefore, the contents described in other embodiments can be freely applied, combined, or replaced with this embodiment.

(Embodiment 4)
In this embodiment mode, an example of a pixel configuration that is different from those in Embodiment Modes 1 to 3 will be described. Figure 2
4 includes a switch 111, a transistor 212, a transistor 213, a transistor 1804, a first liquid crystal element 121, a second liquid crystal element 122, a first storage capacitor 131,
It has a second storage capacitor 132 and a third storage capacitor 1801 . Note that the pixel shown in FIG. 24 is connected to the signal line 116, the scan line 117, and the Cs line 119, and the transistor 1804 and the third storage capacitor 1801 are further provided in the pixel shown in FIG. It is configured as Reference numerals indicating the same elements as those in FIG. 4 are commonly used in the drawings, and descriptions thereof are omitted.

In the third storage capacitor 1801, if a node 1802 is a connection point between the node 142 and a wiring connecting the first electrode of the second storage capacitor 132 and the pixel electrode of the second liquid crystal element 122, It is provided between the node 1802 and the pixel electrode of the second liquid crystal element 122 . In addition, the transistor 1804 is provided between the node 1803 and the signal line 116 when the connection point between the third storage capacitor 1801 and the pixel electrode of the second liquid crystal element 122 is the node 1803 . That is, node 1803 is connected to signal line 116 via transistor 1804 . The transistor 1804 is turned on and off by a signal input to the scanning line 117, like the switch 111, the transistor 212, and the transistor 213. FIG.

The pixel shown in FIG. 24 can also be operated in the same manner as the pixel shown in FIG. Note that in the pixel shown in FIG. 24, the pixel electrodes of the first liquid crystal element 121 and the second liquid crystal element 122 are simultaneously applied with a potential corresponding to the gradation of the pixel from the signal line 116 through the switch 111 and the transistor 1804, respectively. supplied. Therefore, the potential corresponding to the gradation of the pixel can be supplied to the pixel electrode of each liquid crystal element more quickly. Therefore, it is effective for high-speed operation and the like. Note that the on-resistance of the transistor 1804 is preferably higher than the on-resistance of the switch 111 or the transistor 212 . Note that when the channel width of the transistor 1804 is W4 and the channel length is L4, W4/L4 is preferably as small as possible. In addition, in the pixel shown in FIG. 24 as well, since the gradation expressed by the pixel is determined by the orientation of the liquid crystal of each of the first liquid crystal element 121 and the second liquid crystal element 122 in the pixel, the viewing angle can be improved. be able to.

As described above, the viewing angle characteristic can be improved by the present invention. Furthermore, since the configuration enables driving without causing a decrease in contrast, it is possible to provide a liquid crystal display device with higher display quality.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each drawing of this embodiment may be applied, combined or replaced with the content (may be part of) described in the drawing of another embodiment. etc. can be done freely. Furthermore, in the drawings of this embodiment, more drawings can be configured by combining each part with another embodiment.

In addition, the present embodiment is an example of a case where the content (or part of it) described in another embodiment is embodied, an example of a slightly modified case, an example of a partially changed case, and an improved case. An example of the case,
An example of detailed description, an example of application, and an example of related parts are shown. Therefore, the contents described in other embodiments can be freely applied, combined, or replaced with this embodiment.

(Embodiment 5)
In this embodiment mode, an example of a pixel configuration that is different from those in Embodiment Modes 1 to 4 will be described. Figure 25
A pixel shown in FIG. . Note that the pixels shown in FIG.
17 and the Cs line 119, and has a configuration in which a third storage capacitor 1901 is further provided in the pixel shown in FIG. Reference numerals indicating the same elements as those in FIG. 4 are commonly used in the drawings, and descriptions thereof are omitted.

In the third holding capacitor 1901, if the connection point between the node 142 and the wiring connecting the first electrode of the second holding capacitor 132 and the pixel electrode of the second liquid crystal element 122 is a node 1902, It is provided between the node 1902 and the pixel electrode of the second liquid crystal element 122 .

The pixel shown in FIG. 25 can also be operated in the same manner as the pixel shown in FIG. However, by providing the third storage capacitor 1901, it takes time to reach the potential corresponding to the gradation to be supplied to the pixel electrode of the second liquid crystal element 122. FIG. By using this, the viewing angle can be further improved. In addition, since the voltage applied to the second liquid crystal element 122 is determined by capacity division with the third storage capacitor 1901, it is effective when a small voltage is desired to be applied to the second liquid crystal element 122.

In the pixel according to the present embodiment as well, since the gradation expressed by the pixel is determined by the orientation of the liquid crystal of each of the first liquid crystal element 121 and the second liquid crystal element 122 in the pixel, the viewing angle can be improved. be able to.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each drawing of this embodiment may be applied, combined or replaced with the content (may be part of) described in the drawing of another embodiment. etc. can be done freely. Furthermore, in the drawings of this embodiment, more drawings can be configured by combining each part with another embodiment.

In addition, the present embodiment is an example of a case where the content (or part of it) described in another embodiment is embodied, an example of a slightly modified case, an example of a partially changed case, and an improved case. An example of the case,
An example of detailed description, an example of application, and an example of related parts are shown. Therefore, the contents described in other embodiments can be freely applied, combined, or replaced with this embodiment.

(Embodiment 6)
In this embodiment mode, a pixel structure of a display device will be described. In particular, the pixel structure of the liquid crystal display device will be described.

A pixel structure in which each liquid crystal mode and a transistor are combined will be described with reference to cross-sectional views of pixels.

Note that as the transistor, a thin film transistor (TFT) including a non-single-crystal semiconductor layer typified by amorphous silicon, polycrystalline silicon, microcrystalline (also referred to as microcrystalline or semi-amorphous) silicon, or the like can be used. As a structure of the transistor, a top-gate type, a bottom-gate type, or the like can be used. Note that a channel-etched transistor, a channel-protected transistor, or the like can be used as the bottom-gate transistor.

FIG. 28 is an example of a cross-sectional view of a pixel in which the TN method and a transistor are combined.
Features of the pixel structure shown in FIG. 28 will be described.

The liquid crystal molecules 2018 shown in FIG. 28 are elongated molecules with long and short axes. here,
The orientation of the liquid crystal molecules 2018 is represented by the length of the liquid crystal molecules shown in the figure. i.e.
The longer liquid crystal molecules 2018 have their major axes parallel to the plane of the paper (the cross-sectional direction shown in FIG. 28), and the shorter the liquid crystal molecules 2018 have their major axes oriented normal to the plane of the paper. is close to Liquid crystal molecules 2018 shown in FIG.
, and the second substrate 2016, the orientation of the long axis of the liquid crystal molecules is different by 90 degrees, and the orientation of the long axis of the liquid crystal molecules 2018 located between these substrates smooths them. It is oriented to connect. That is, the liquid crystal molecules 2018 shown in FIG.
Between the substrate 2001 and the second substrate 2016, the orientation is such that it is twisted by 90 degrees.

Note that the case where a bottom-gate transistor including an amorphous semiconductor is used as the transistor is described. When a transistor including an amorphous semiconductor is used, a liquid crystal display device can be manufactured at low cost using a large substrate.

A liquid crystal display device has a main part called a liquid crystal panel that displays an image. The liquid crystal panel is made by bonding two processed substrates together with a gap of several micrometers.
It is produced by injecting a liquid crystal material between two substrates. That is, the liquid crystal is formed between the first substrate and the second substrate.
It is sandwiched between two substrates. In FIG. 28, liquid crystal 201
1 is sandwiched between a first substrate 2001 and a second substrate 2016 . First substrate 200
A transistor and a pixel electrode are formed on the first substrate 2016, and a light shielding film 201 is formed on the second substrate 2016.
4. A color filter 2015, a fourth conductive layer 2013, a spacer 2017 and a second alignment film 2012 are formed.

By providing the light shielding film 2014, a display device with little light leakage when displaying black can be obtained. Note that the light shielding film 2014 may not be particularly formed on the second substrate 2016 . When the light shielding film 2014 is not formed, the number of steps can be reduced, so that the manufacturing cost can be reduced and the yield can be improved.

Further, the color filter 2015 may not be formed over the second substrate 2016 . Even if the color filter 2015 is not formed, the number of steps can be reduced as in the case of the light shielding film, so that the manufacturing cost can be reduced and the yield can be improved. however,
Even if the color filter 2015 is not formed, a display device capable of color display can be obtained by field sequential driving.

Also, instead of the spacers 2017, spherical spacers may be scattered. When spherical spacers are scattered, the manufacturing cost can be reduced because the number of steps is reduced. Also, the yield can be improved. On the other hand, when the spacers 2017 are formed, the positions of the spacers do not fluctuate, so the distance between the two substrates can be more easily made constant, and a display device with little display unevenness can be obtained.

Next, processing applied to the first substrate 2001 will be described.

First, a first insulating film 2002 is formed on a first substrate 2001 by a sputtering method, a printing method, a coating method, or the like. The first insulating film 2002 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor. However, when quartz is used as the substrate 2001, the first insulating film 2002 may not be formed.

Next, a first conductive layer 2003 is formed on the first insulating film 2002 using a photolithography method, a laser direct drawing method, an inkjet method, or the like.

Next, a second insulating film 2004 is formed on the entire surface by a sputtering method, a printing method, a coating method, or the like. The second insulating film 2004 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor.

Next, a first semiconductor layer 2005 and a second semiconductor layer 2006 are formed. Note that the first semiconductor layer 2005 and the second semiconductor layer 2006 are formed continuously, and their shapes are processed at the same time.

Next, a second conductive layer 2007 is formed by a photolithography method, a laser direct writing method, an inkjet method, or the like. Note that dry etching is preferably used as an etching method for processing the shape of the second conductive layer 2007 . Note that the second conductive layer 2007 may be made of a transparent material or a reflective material.

Next, a channel region of the transistor is formed. An example of the process will be described. The second semiconductor layer 2006 is etched using the second conductive layer 2007 as a mask. again,
A mask for processing the shape of the second conductive layer 2007 may be used as the mask for etching. A portion of the first semiconductor layer 2005 from which the second semiconductor layer 2006 is removed becomes a channel region of the transistor. By forming the channel region in this way, it is possible to reduce the number of masks, thereby reducing the manufacturing cost.

Next, a third insulating film 2008 is formed, and contact holes are selectively formed in the third insulating film 2008 . Note that contact holes may be formed in the second insulating film 2004 at the same time that the contact holes are formed in the third insulating film 2008 . Note that the surface of the third insulating film 2008 is preferably as flat as possible. This is because the unevenness of the surface in contact with the liquid crystal, that is, the surface of the third insulating film 2008 affects the orientation of the liquid crystal molecules.

Next, a third conductive layer 2009 is formed by a photolithography method, a laser direct writing method, an inkjet method, or the like.

Next, a first alignment film 2010 is formed. After forming the first alignment film 2010, rubbing treatment may be performed to control the alignment of the liquid crystal molecules.

A first substrate 2001 manufactured as described above, a light shielding film 2014, and a color filter 2015
, a fourth conductive layer 2013, a spacer 2017 and a second alignment film 2012 are formed.
and the substrate 2016 are bonded with a sealing material with a gap of several micrometers. A liquid crystal material is then injected between the two substrates. Note that the fourth conductive layer 2013 is formed on the entire surface of the second substrate 2016 in the TN method.

FIG. 29(A) shows MVA (Multi-domain Vertical Alignment
ent) is an example of a cross-sectional view of a pixel when the method and a transistor are combined. Figure 29
By applying the pixel structure shown in (A) to the liquid crystal display device of the present invention, the viewing angle can be further increased.

Using the pixel structure shown in FIG. 29A, the characteristics of the pixel structure of the MVA liquid crystal panel will be described. The liquid crystal molecules 2118 shown in FIG. 29A correspond to the liquid crystal molecules 201 shown in FIG.
Like 8, it is an elongated molecule with a long axis and a short axis. Therefore, in FIG. 29A as well, the orientation of the liquid crystal molecules 2118 is represented by the length of the liquid crystal molecules shown in the drawing. In other words, Figure 2
The liquid crystal molecules 2118 shown in 9A are oriented so that their long axes are directed in the normal direction to the orientation film. Also, the liquid crystal molecules 2118 in the portion where the alignment control protrusion 2119 is located are radially aligned with the alignment control protrusion 2119 as the center. With this state, a liquid crystal display device with a wide viewing angle can be obtained.

Note that the case where a bottom-gate transistor including an amorphous semiconductor is used as the transistor is described. When a transistor including an amorphous semiconductor is used, a liquid crystal display device can be manufactured at low cost using a large substrate.

In FIG. 29A, two substrates sandwiching the liquid crystal 2111 correspond to the first substrate 2101 and the second substrate 2116 . Note that a transistor and a pixel electrode are formed on the first substrate 2101, and a light-shielding film 2114, a color filter 2115, and a light-shielding film 2114 are formed on the second substrate 2116.
A fourth conductive layer 2113, a spacer 2117, a second alignment film 2112, and an alignment control projection 2119 are formed.

By providing the light shielding film 2114, a display device with little light leakage when displaying black can be obtained. Note that the light shielding film 2114 may not be particularly formed on the second substrate 2116 . When the light shielding film 2114 is not formed, the number of steps can be reduced, so that the manufacturing cost can be reduced and the yield can be improved.

In addition, the color filter 2115 may not be formed over the second substrate 2116 . Even if the color filter 2115 is not formed, the number of steps can be reduced as in the case of the light shielding film, so that the manufacturing cost can be reduced and the yield can be improved. however,
Even if the color filter 2115 is not formed, a display device capable of color display can be obtained by field sequential driving.

Also, instead of the spacers 2117, spherical spacers may be scattered. When spherical spacers are scattered, the manufacturing cost can be reduced because the number of steps is reduced. Also, the yield can be improved. On the other hand, when the spacers 2117 are formed, the positions of the spacers do not fluctuate, so the distance between the two substrates can be more easily made constant, and a display device with little display unevenness can be obtained.

Processing performed on the first substrate 2101 will be described.

First, a first insulating film 2102 is formed on a first substrate 2101 by a sputtering method, a printing method, a coating method, or the like. The first insulating film 2102 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor. However, when quartz is used as the substrate 2101, the first insulating film 2102 may not be formed.

Next, a first conductive layer 2103 is formed on the first insulating film 2102 using a photolithography method, a laser direct drawing method, an inkjet method, or the like.

Next, a second insulating film 2104 is formed on the entire surface by a sputtering method, a printing method, a coating method, or the like. The second insulating film 2104 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor.

Next, a first semiconductor layer 2105 and a second semiconductor layer 2106 are formed. Note that the first semiconductor layer 2105 and the second semiconductor layer 2106 are formed continuously, and their shapes are processed at the same time.

Next, a second conductive layer 2107 is formed by a photolithography method, a laser direct writing method, an inkjet method, or the like. Note that dry etching is preferably used as an etching method for processing the shape of the second conductive layer 2107 . Note that as the second conductive layer 2107, a transparent material or a reflective material may be used.

Next, a channel region of the transistor is formed. An example of the process will be described. The second semiconductor layer 225 is etched using the second conductive layer 2107 as a mask. Alternatively, etching may be performed using a mask for processing the shape of the second conductive layer 2107 as a mask. A portion of the first semiconductor layer 2105 from which the second semiconductor layer 2106 is removed becomes a channel region of the transistor. By forming the channel region in this way, it is possible to reduce the number of masks, thereby reducing the manufacturing cost.

Next, a third insulating film 2108 is formed, and contact holes are selectively formed in the third insulating film 2108 . Note that contact holes may be formed in the second insulating film 2104 at the same time that the contact holes are formed in the third insulating film 2108 .

Next, a third conductive layer 2109 is formed by a photolithography method, a laser direct writing method, an inkjet method, or the like.

Next, a first alignment film 2110 is formed. Note that after forming the first alignment film 2110, rubbing treatment may be performed in order to control the alignment of the liquid crystal molecules.

A first substrate 2101 manufactured as described above, a light shielding film 2114, and a color filter 2115
, a fourth conductive layer 2113, a spacer 2117, and a second alignment film 2112.
and the substrate 2116 of , are bonded with a sealing material with a gap of several micrometers. A liquid crystal material is then injected between the two substrates.

Note that the fourth conductive layer 2113 is formed over the entire surface of the second substrate 2116 in the MVA method. Also, an alignment control projection 2119 is formed in contact with the fourth conductive layer 2113 . The shape of the orientation control projection 2119 is preferably a shape with a smooth curved surface. By doing so, the alignment defects of the liquid crystal molecules 2118 due to the alignment control projections 2119 are reduced. In addition, since the alignment film formed on the alignment control projection 2119 can be prevented from being broken, defects of the alignment film due to the break can be reduced.

FIG. 29B shows PVA (Patterned Vertical Alignment)
FIG. 10 is an example of a cross-sectional view of a pixel in which a method and a transistor are combined; By applying the pixel structure shown in FIG. 29B to the liquid crystal display device of the present invention, the viewing angle can be further increased.

Features of the pixel structure shown in FIG. 29B will be described. Liquid crystal molecule 2 shown in FIG. 29(B)
148 is similar to the liquid crystal molecule 2018 shown in FIG.
The orientation of 148 is represented by the length of the liquid crystal molecules shown in the figure. Therefore, FIG.
) are oriented so that their long axes are oriented in the normal direction to the orientation film. Liquid crystal molecules 2148 existing around the electrode cutout 2149 where the fourth conductive layer 2143 is not provided are radially aligned with the boundary between the electrode cutout 2149 and the fourth conductive layer 2143 as the center. With this state, a liquid crystal display device with a wide viewing angle can be obtained.

Note that the case where a bottom-gate transistor including an amorphous semiconductor is used as the transistor is described. When a transistor including an amorphous semiconductor is used, a liquid crystal display device can be manufactured at low cost using a large substrate.

In FIG. 29B, the two substrates sandwiching the liquid crystal 2141 correspond to the first substrate 2131 and the second substrate 2146 . Note that a transistor and a pixel electrode are formed on the first substrate 2131, and a light shielding film 2144, a color filter 2145, and a light shielding film 2144 are formed on the second substrate 2146.
A fourth conductive layer 2143, spacers 2147, and a second alignment film 2142 are formed.

By providing the light shielding film 2144, a display device with little light leakage when displaying black can be obtained. Note that the light shielding film 2144 may not be particularly formed on the second substrate 2146 . When the light shielding film 2144 is not formed, the number of steps can be reduced, so that the manufacturing cost can be reduced and the yield can be improved.

In addition, the color filter 2145 may not be formed over the second substrate 2146 . Even if the color filter 2145 is not formed, the number of steps can be reduced as in the case of the light shielding film, so that the manufacturing cost can be reduced and the yield can be improved. however,
Even if the color filter 2145 is not formed, a display device capable of color display can be obtained by field sequential driving.

Also, instead of the spacers 2147, spherical spacers may be scattered. When spherical spacers are scattered, the manufacturing cost can be reduced because the number of steps is reduced. Also, the yield can be improved. On the other hand, when the spacers 2147 are formed, the positions of the spacers do not fluctuate, so the distance between the two substrates can be more easily made constant, and a display device with little display unevenness can be obtained.

Processing performed on the first substrate 2131 will be described.

First, a first insulating film 2132 is formed on a first substrate 2131 by a sputtering method, a printing method, a coating method, or the like. The first insulating film 2132 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor. However,
When quartz is used as the substrate 2131, the first insulating film 2132 may not be formed.

Next, a first conductive layer 2133 is formed over the first insulating film 2132 using a photolithography method, a laser direct drawing method, an inkjet method, or the like.

Next, a second insulating film 2134 is formed on the entire surface by a sputtering method, a printing method, a coating method, or the like. The second insulating film 2134 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor.

Next, a first semiconductor layer 2135 and a second semiconductor layer 2136 are formed. Note that the first semiconductor layer 2135 and the second semiconductor layer 2136 are formed continuously, and their shapes are processed at the same time.

Next, a second conductive layer 2137 is formed by a photolithography method, a laser direct writing method, an inkjet method, or the like. Note that dry etching is preferably used as an etching method for processing the shape of the second conductive layer 2137 . Note that a transparent material or a reflective material may be used for the second conductive layer 2137 .

Next, a channel region of the transistor is formed. An example of the process will be described. The second semiconductor layer 2136 is etched using the second conductive layer 2137 as a mask. again,
A mask for processing the shape of the second conductive layer 2137 may be used as a mask for etching. A portion of the first semiconductor layer 2135 from which the second semiconductor layer 2136 is removed becomes a channel region of the transistor. By forming the channel region in this way, it is possible to reduce the number of masks, thereby reducing the manufacturing cost.

Next, a third insulating film 2138 is formed, and contact holes are selectively formed in the third insulating film 2138 . Note that a contact hole may be formed in the second insulating film 2134 at the same time that the contact hole is formed in the third insulating film 2138 .

Next, a third conductive layer 2139 is formed by a photolithography method, a laser direct drawing method, an inkjet method, or the like.

Next, a first alignment film 2140 is formed. Note that after forming the first alignment film 2140, rubbing treatment may be performed in order to control the alignment of the liquid crystal molecules.

A first substrate 2131 manufactured as described above, a light shielding film 2144, and a color filter 2145
, the fourth conductive layer 2143, the spacer 2147, and the second substrate 2146 on which the second alignment film 2142 is formed are bonded together with a sealing material with a gap of several micrometers. A liquid crystal material is then injected between the two substrates.

In the PVA method, the fourth conductive layer 2143 is patterned to form the electrode notch 2149 . Although the shape of the electrode cutout portion 2149 is not particularly limited, it is preferable that the shape is a combination of a plurality of rectangles with different orientations. By doing this,
Since a plurality of regions with different orientations can be formed, a liquid crystal display device with a wide viewing angle can be obtained. The shape of the fourth conductive layer 2143 at the boundary between the electrode notch 2149 and the fourth conductive layer 2143 preferably has a smooth slope with respect to its base. By doing so, alignment defects of the liquid crystal molecules 2148 adjacent to the slope are reduced. Further, since the discontinuity of the alignment film formed over the fourth conductive layer 2143 can be prevented, defects of the alignment film due to the discontinuity can be reduced.

FIG. 30A is an example of a cross-sectional view of a pixel in which an IPS (In-Plane-Switching) method and a transistor are combined. By applying the pixel structure shown in FIG. 30A to the liquid crystal display device of the present invention, the viewing angle can be further increased.

Features of the pixel structure shown in FIG. 30A will be described. Liquid crystal molecule 2 shown in FIG.
248 is an elongated molecule having a long axis and a short axis like the liquid crystal molecule 2018 shown in FIG. Therefore, in FIG. 30A as well, the orientation of the liquid crystal molecules 2218 is represented by the length of the liquid crystal molecules shown in the drawing. In other words, the liquid crystal molecules 2218 shown in FIG. 30A are oriented so that their long axes are always parallel to the substrate. Fig. 30(A)
, the liquid crystal molecule 2
218 orientation, when an electric field is applied to the liquid crystal molecules 2218, they rotate in the horizontal plane while the orientation of the long axis is always kept horizontal to the substrate. With this state, a liquid crystal display device with a wide viewing angle can be obtained.

Note that the case where a bottom-gate transistor including an amorphous semiconductor is used as the transistor is described. When a transistor including an amorphous semiconductor is used, a liquid crystal display device can be manufactured at low cost using a large substrate.

In FIG. 30A, the two substrates sandwiching the liquid crystal 2211 correspond to the first substrate 2201 and the second substrate 2216 . Note that a transistor and a pixel electrode are formed over the first substrate 2201 , and a light shielding film 2214 and a color filter 2215 are formed over the second substrate 2216 .
, a spacer 2217, and a second alignment film 2212 are formed.

By providing the light shielding film 2214, a display device with little light leakage when displaying black can be obtained. Note that the light shielding film 2214 may not be particularly formed on the second substrate 2216 . When the light shielding film 2214 is not formed, the number of steps can be reduced, so that the manufacturing cost can be reduced and the yield can be improved.

In addition, the color filter 2215 may not be formed over the second substrate 2216 . Even if the color filter 2215 is not formed, the number of steps can be reduced as in the case of the light shielding film, so that the manufacturing cost can be reduced and the yield can be improved. however,
Even if the color filter 2215 is not formed, a display device capable of color display can be obtained by field sequential driving.

Also, instead of the spacers 2217, spherical spacers may be scattered. When spherical spacers are scattered, the manufacturing cost can be reduced because the number of steps is reduced. Also, the yield can be improved. On the other hand, when the spacers 2217 are formed, the positions of the spacers do not fluctuate, so the distance between the two substrates can be more easily made constant, and a display device with little display unevenness can be obtained.

Processing performed on the first substrate 2201 will be described.

First, a first insulating film 2202 is formed on a first substrate 2201 by a sputtering method, a printing method, a coating method, or the like. The first insulating film 2202 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor. However, when quartz is used as the substrate 2201, the first insulating film 2202 may not be formed.

Next, a first conductive layer 2203 is formed on the first insulating film 2202 using a photolithography method, a laser direct drawing method, an inkjet method, or the like.

Next, a second insulating film 2204 is formed on the entire surface by a sputtering method, a printing method, a coating method, or the like. The second insulating film 2204 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor.

Next, a first semiconductor layer 2205 and a second semiconductor layer 2206 are formed. Note that the first semiconductor layer 2205 and the second semiconductor layer 2206 are formed continuously, and their shapes are processed at the same time.

Next, a second conductive layer 2207 is formed by a photolithography method, a laser direct writing method, an inkjet method, or the like. Note that dry etching is preferably used as an etching method for processing the shape of the second conductive layer 2207 . Note that as the second conductive layer 2207, a transparent material or a reflective material may be used.

Next, a channel region of the transistor is formed. An example of the process will be described. The second semiconductor layer 2206 is etched using the second conductive layer 2207 as a mask. again,
A mask for processing the shape of the second conductive layer 2207 may be used as the mask for etching. A portion of the first semiconductor layer 2205 from which the second semiconductor layer 2206 is removed becomes a channel region of the transistor. By forming the channel region in this way, it is possible to reduce the number of masks, thereby reducing the manufacturing cost.

Next, a third insulating film 2208 is formed, and contact holes are selectively formed in the third insulating film 2208 . Note that contact holes may be formed in the second insulating film 2204 at the same time that the contact holes are formed in the third insulating film 2208 .

Next, a third conductive layer 2209 is formed by a photolithography method, a laser direct drawing method, an inkjet method, or the like. Here, the shape of the third conductive layer 2209 is two comb teeth that are meshed with each other. One comb-shaped electrode is electrically connected to one of the source electrode and the drain electrode of the transistor, and the other comb-shaped electrode is electrically connected to a common electrode. By doing so, a horizontal electric field can be effectively applied to the liquid crystal molecules 2218 .

Next, a first alignment film 2210 is formed. Note that after forming the first alignment film 2210, rubbing treatment may be performed in order to control the alignment of the liquid crystal molecules.

A first substrate 2201 manufactured as described above, a light shielding film 2214, and a color filter 2215
, a spacer 2217, and a second substrate 2216 on which a second alignment film 2212 is formed are bonded together with a sealing material with a gap of several micrometers. A liquid crystal material is then injected between the two substrates.

FIG. 30B is an example of a cross-sectional view of a pixel in which a fringe field switching (FFS) method and a transistor are combined. By applying the pixel structure shown in FIG. 30B to the liquid crystal display device of the present invention, the viewing angle can be further increased.

Features of the pixel structure shown in FIG. 30B will be described. Liquid crystal molecule 2 shown in FIG. 30(B)
248, similar to the liquid crystal molecules 2018 shown in FIG. 28, the liquid crystal molecules 21
The orientation of 48 is represented by the length of the liquid crystal molecules shown in the figure. Therefore, FIG. 30(B)
liquid crystal molecules 2248 shown in FIG. FIG. 30B shows the orientation of the liquid crystal molecules 2248 in a state where no electric field is generated in the region where the liquid crystal 2241 exists. rotates in the horizontal plane while always maintaining the horizontal direction with respect to the substrate. With this state, a liquid crystal display device with a wide viewing angle can be obtained.

Note that the case where a bottom-gate transistor including an amorphous semiconductor is used as the transistor is described. When a transistor including an amorphous semiconductor is used, a liquid crystal display device can be manufactured at low cost using a large substrate.

In FIG. 30B, the two substrates sandwiching the liquid crystal 2241 correspond to the first substrate 2231 and the second substrate 2246 . Note that a transistor and a pixel electrode are formed on the first substrate 2241, and a light shielding film 2244, a color filter 2245, and a light shielding film 2244 are formed on the second substrate 2246.
A spacer 2247 and a second alignment film 2242 are formed.

By providing the light shielding film 2244, a display device with less light leakage when displaying black can be obtained. Note that the light shielding film 2244 may not be particularly formed on the second substrate 2246 . When the light shielding film 2244 is not formed, the number of steps can be reduced, so that the manufacturing cost can be reduced and the yield can be improved.

Further, the color filter 2245 may not be formed over the second substrate 2246 . Even if the color filter 2245 is not formed, the number of steps can be reduced as in the case of the light shielding film, so that the manufacturing cost can be reduced and the yield can be improved. however,
Even if the color filter 2245 is not formed, a display device capable of color display can be obtained by field sequential driving.

Also, instead of the spacers 2247, spherical spacers may be scattered. When spherical spacers are scattered, the manufacturing cost can be reduced because the number of steps is reduced. Also, the yield can be improved. On the other hand, when the spacers 2247 are formed, the positions of the spacers do not fluctuate, so the distance between the two substrates can be more easily made constant, and a display device with little display unevenness can be obtained.

Processing performed on the first substrate 2231 will be described.

First, a first insulating film 2232 is formed on a first substrate 2231 by a sputtering method, a printing method, a coating method, or the like. The first insulating film 2232 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor. However,
When quartz is used as the substrate 2231, the first insulating film 2232 may not be formed.

Next, a first conductive layer 2233 is formed over the first insulating film 2232 using a photolithography method, a laser direct drawing method, an inkjet method, or the like.

Next, a second insulating film 2234 is formed on the entire surface by a sputtering method, a printing method, a coating method, or the like. The second insulating film 2234 has a function of preventing impurities from the substrate from affecting the semiconductor layer and changing the properties of the transistor.

Next, a first semiconductor layer 2235 and a second semiconductor layer 2236 are formed. Note that the first semiconductor layer 2235 and the second semiconductor layer 2236 are formed continuously, and their shapes are processed at the same time.

Next, a second conductive layer 2237 is formed by a photolithography method, a laser direct writing method, an inkjet method, or the like. Note that dry etching is preferably used as an etching method for processing the shape of the second conductive layer 2237 . Note that a transparent material or a reflective material may be used for the second conductive layer 2237 .

Next, a channel region of the transistor is formed. An example of the process will be described. The second semiconductor layer 2236 is etched using the second conductive layer 2237 as a mask. again,
A mask for processing the shape of the second conductive layer 2237 may be used as a mask for etching. A portion of the first semiconductor layer 2235 from which the second semiconductor layer 2236 is removed becomes a channel region of the transistor. By forming the channel region in this way, it is possible to reduce the number of masks, thereby reducing the manufacturing cost.

Next, a third insulating film 2238 is formed, and contact holes are selectively formed in the third insulating film 2238 .

Next, a third conductive layer 2239 is formed by a photolithography method, a laser direct drawing method, an inkjet method, or the like.

Next, a fourth insulating film 2249 is formed, and contact holes are selectively formed in the fourth insulating film 2249 .

Next, a fourth conductive layer 2243 is formed by a photolithography method, a laser direct drawing method, an inkjet method, or the like. Here, the fourth conductive layer 2243 has a comb-like shape.

Next, a first alignment film 2240 is formed. Note that after forming the first alignment film 2240, rubbing treatment may be performed in order to control the alignment of the liquid crystal molecules.

A first substrate 2231 manufactured as described above, a light shielding film 2244, and a color filter 2245
, a spacer 2247, and a second substrate 2246 on which a second alignment film 2242 is formed are bonded together with a gap of several micrometers by a sealing material, and a liquid crystal material is injected between the two substrates. A liquid crystal panel can be produced.

Here, materials that can be used for each conductive layer or each insulating film are described.

The first insulating film 2002 in FIG. 28, the first insulating film 2102 in FIG. 29A, the first insulating film 2132 in FIG. 29B, the first insulating film 2202 in FIG. As the first insulating film 2232 of 30(B), a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (Si
OxNy) or other insulating films can be used. Further, these insulating films are silicon oxide films,
An insulating film having a laminated structure in which two or more films such as a silicon nitride film or a silicon oxynitride film (SiOxNy) are combined can be used.

The first conductive layer 2003 in FIG. 28, the first conductive layer 2103 in FIG. 29A, the first conductive layer 2133 in FIG. 29B, the first conductive layer 2203 in FIG. A conductive material such as Mo, Ti, Al, Nd, or Cr can be used for the first conductive layer 2233 of 30(B). These conductive layers are made of conductive materials such as Mo, Ti, Al, Nd, and Cr.
A laminate structure in which two or more are combined can also be used.

The second insulating film 2004 in FIG. 28, the second insulating film 2104 in FIG. 29A, the second insulating film 2134 in FIG. 29B, the second insulating film 2204 in FIG. As the second insulating film 2234 in 30B, a thermal oxide film, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or the like can be used. Alternatively, a stacked structure in which two or more of a thermal oxide film, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or the like is combined can be used. Note that the portion in contact with the semiconductor layer is preferably a silicon oxide film. This is because the use of a silicon oxide film reduces the trap level at the interface with the semiconductor layer. Note that the portion in contact with Mo is preferably a silicon nitride film. This is because the silicon nitride film does not oxidize Mo.

The first semiconductor layer 2005 in FIG. 28, the first semiconductor layer 2105 in FIG.
), the first semiconductor layer 2205 in FIG. 30A, and the first semiconductor layer 2235 in FIG. 30B, silicon, silicon germanium (SiGe), or the like can be used. .

The second semiconductor layer 2006 in FIG. 28, the second semiconductor layer 2106 in FIG.
), the second semiconductor layer 2206 in FIG. 30A, and the second semiconductor layer 2236 in FIG. 30B, silicon containing phosphorus or the like can be used.

The second conductive layer 2007 and the third conductive layer 2009 in FIG. 28, the second conductive layer 2107 and the third conductive layer 2109 in FIG. 29A, the second conductive layer 2137 in FIG. The second conductive layer 2139, the second conductive layer 2207 and the second conductive layer 2209 in FIG. 30A, or the second conductive layer 2237, the third conductive layer 2239 and the fourth conductive layer 2239 in FIG. conductive layer 224 of
Materials having transparency of 3 include an indium tin oxide (ITO) film in which tin oxide is mixed with indium oxide, an indium tin silicon oxide (ITSO) film in which silicon oxide is mixed with indium tin oxide (ITO), Indium zinc oxide (indium zinc oxide mixed with indium oxide)
IZO) film, zinc oxide film, tin oxide film, or the like can be used. Note that IZO is
It can be formed by sputtering using a target in which 2 to 20 wt % of zinc oxide (ZnO) is mixed with TO.

28, the second conductive layer 2107 and the third conductive layer 2109 in FIG. 29A, and the second conductive layer in FIG. 2137 and the second conductive layer 2139, the second conductive layer 2207 and the second conductive layer 2209 in FIG.
Alternatively, Ti, Mo, Ta, Cr, W, Al, or the like is used as a reflective material for the second conductive layer 2237, the second conductive layer 2239, and the fourth conductive layer 2243 in FIG. be able to. Alternatively, a two-layer structure in which Ti, Mo, Ta, Cr, W and Al are laminated,
A three-layer laminated structure in which Al is sandwiched between metals such as Ti, Mo, Ta, Cr, and W may be employed.

The third insulating film 2008 in FIG. 28, the third insulating film 2108 in FIG. 29A, the third insulating film 2138 in FIG. 29B, the third conductive layer 2139 in FIG. 30A, the third insulating film 2238 and the fourth insulating film 2249 in FIG. A dielectric constant organic compound material (photosensitive or non-photosensitive organic resin material) or the like can be used. A material containing siloxane can also be used. Note that siloxane is silicon (Si)
and oxygen (O) to form a skeletal structure. As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aryl group) is used. Alternatively, a fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as substituents.

The first alignment film 2010 in FIG. 28, the first alignment film 2110 in FIG. 29A, the first alignment film 2140 in FIG. 29B, the first alignment film 2210 in FIG. A polymer film such as polyimide can be used as the first alignment film 2240 of 30(B).

Next, a pixel structure when each liquid crystal mode and a transistor are combined will be described with reference to a top view (layout diagram) of a pixel.

Liquid crystal modes include TN (Twisted Nematic) mode, IPS (
In-Plane-Switching) mode, FFS (Fringe Field)
Switching) mode, MVA (Multi-domain Vertical)
alignment) mode, PVA (Patterned Vertical Ali
gnment), ASM (Axially Symmetrically aligned Mi
cro-cell) mode, OCB (Optical Compensated Bir
efringence) mode, FLC (Ferroelectric Liquid
Crystal) mode, AFLC (Anti-Ferroelectric Liqui
d Crystal) and the like can be used.

Note that as the transistor, a thin film transistor (TFT) including a non-single-crystal semiconductor layer typified by amorphous silicon, polycrystalline silicon, microcrystalline (also referred to as microcrystalline or semi-amorphous) silicon, or the like can be used.

Note that as a structure of the transistor, a top-gate type, a bottom-gate type, or the like can be used. As a bottom-gate transistor, a channel-etched transistor, a channel-protected transistor, or the like can be used.

FIG. 31 shows an example of a top view of a pixel in which the TN system and transistors are combined.

The pixel shown in FIG. 31 includes a first transistor 2304, a second transistor 2305, a third
, a first liquid crystal capacitor, a second liquid crystal capacitor, a first storage capacitor, and a second storage capacitor, and are connected to a scanning line 2301, a signal line 2302, and a Cs line 2311. . Note that the equivalent circuit diagram of the pixel configuration shown in FIG. 31 is the same as that of FIG. 6, so detailed description thereof will be omitted.

In FIG. 31, the pixel electrode forming the first liquid crystal capacitor corresponds to the pixel electrode 2307 and the pixel electrode forming the second liquid crystal capacitor corresponds to the pixel electrode 2308 . The first storage capacitor is composed of a capacitor line 2312 connected to the Cs line 2311 outside the pixel portion, a semiconductor layer 2309 connected to the pixel electrode 2307, and an insulating film provided therebetween. ing. Similarly to the first storage capacitor, the second storage capacitor is composed of a capacitor line 2312, a semiconductor layer 2310 connected to the pixel electrode 2308, and an insulating film provided therebetween. Note that the capacitor line 2312 forming the first storage capacitor and the second storage capacitor is a transistor 2304
2306 including the scanning line 2301 and the Cs line 2301 including the gate electrode, and the semiconductor layer 2
309 and 2310 are manufactured in the same process as the semiconductor layers including source regions, drain regions and channel forming regions that constitute the transistors 2304 to 2306 . Further, in the insulating films forming the first storage capacitor and the second storage capacitor, the transistors 2304 to 2306
A film manufactured in the same process as that of the gate insulating film constituting the can be used.

As shown in FIG. 31, two liquid crystal capacitors with different alignment states can be used to obtain a liquid crystal display device with excellent viewing angle characteristics. Note that the top view shown in FIG. 31 is an example, and the present invention is not limited to this.

Note that when each transistor has a structure in which one of a source electrode and a drain electrode surrounds the other electrode, a channel width can be increased. Such a structure is particularly effective when an amorphous semiconductor layer having a lower mobility than a crystalline semiconductor layer is used as a semiconductor layer of a transistor forming a pixel.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each figure of this embodiment is applied or combined with the content (may be part of) described in the figures of other embodiments and examples. , or can be freely replaced. Furthermore, in the drawings of this embodiment, more drawings can be formed by combining parts of other embodiments and examples with respect to each part.

In this embodiment, the contents (or part of them) described in other embodiments and examples are
Example of implementation, example of slight modification, example of partial change, example of improvement, example of detailed description, example of application, example of related parts etc. Therefore, the contents described in other embodiments and examples can be freely applied to, combined with, or replaced with this embodiment.

(Embodiment 7)
In this embodiment mode, various liquid crystal modes will be described with reference to cross-sectional views.

32A and 32B show schematic diagrams of cross sections in TN mode.

A liquid crystal layer 3300 is sandwiched between a first substrate 3301 and a second substrate 3302 which are arranged to face each other. A first electrode 3305 is formed on the upper surface of the first substrate 3301 . A second electrode 3306 is formed on the upper surface of the second substrate 3302 . A first polarizing plate 3303 is arranged on the side of the first substrate 3301 opposite to the liquid crystal layer. second
A second polarizing plate 3304 is arranged on the side of the substrate 3302 opposite to the liquid crystal layer. note that,
The first polarizing plate 3303 and the second polarizing plate 3304 are arranged so as to form crossed Nicols.

The first polarizing plate 3303 may be arranged on the top surface of the first substrate 3301 . A second polarizer 3304 may be placed on top of the second substrate 3302 .

At least one (or both) of the first electrode 3305 and the second electrode 3306 should be translucent (transmissive or reflective). Alternatively, both electrodes may be translucent and part of one electrode may be reflective (transflective).

FIG. 32A is a schematic cross-sectional view when a voltage is applied to the first electrode 3305 and the second electrode 3306 (referred to as a vertical electric field method). Since the liquid crystal molecules are aligned vertically, the light from the backlight is not affected by the birefringence of the liquid crystal molecules. And the first polarizing plate 3303
and the second polarizing plate 3304 are arranged in crossed Nicols, light from the backlight cannot pass through the substrate. Therefore, black display is performed.

FIG. 32B is a schematic cross-sectional view when no voltage is applied to the first electrode 3305 and the second electrode 3306. FIG. Liquid crystal molecules are arranged side by side, and from the first electrode 3305 to the second electrode 3
Since it is in a state of rotation toward 306, the light from the backlight is affected by the birefringence of the liquid crystal molecules. Since the first polarizing plate 3303 and the second polarizing plate 3304 are arranged in crossed Nicols, the light from the backlight passes through the substrate. Therefore, white display is performed. This is the so-called normally white mode.

By controlling the voltage applied to the first electrode 3305 and the second electrode 3306, it is possible to control the state of the liquid crystal molecules, that is, the orientation. Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

The liquid crystal display device having the structure shown in FIGS. 32A and 32B can perform full-color display by providing a color filter. A color filter can be provided on the first substrate 3301 side or the second substrate 3302 side.

A known liquid crystal material may be used for the TN mode.

FIGS. 33A and 33B show schematic diagrams of cross sections in VA mode. The VA mode is a mode in which the liquid crystal molecules are oriented perpendicular to the substrate when no electric field is applied.

A liquid crystal layer 3400 is sandwiched between a first substrate 3401 and a second substrate 3402 which are arranged to face each other. A first electrode 3405 is formed on the upper surface of the first substrate 3401 . A second electrode 3406 is formed on the upper surface of the second substrate 3402 . A first polarizing plate 3403 is arranged on the side of the first substrate 3401 opposite to the liquid crystal layer. second
A second polarizing plate 3404 is arranged on the side of the substrate 3402 opposite to the liquid crystal layer. note that,
The first polarizing plate 3403 and the second polarizing plate 3404 are arranged so as to form crossed Nicols.

The first polarizing plate 3403 may be arranged on the top surface of the first substrate 3401 . A second polarizer 3404 may be placed on top of the second substrate 3402 .

At least one (or both) of the first electrode 3405 and the second electrode 3406 should be translucent (transmissive or reflective). Alternatively, both electrodes may be translucent and part of one electrode may be reflective (transflective).

FIG. 33A is a schematic cross-sectional view when a voltage is applied to the first electrode 3405 and the second electrode 3406 (referred to as a vertical electric field method). Since the liquid crystal molecules are arranged horizontally, the light from the backlight is affected by the birefringence of the liquid crystal molecules. Since the first polarizing plate 3403 and the second polarizing plate 3404 are arranged in crossed Nicols, the light from the backlight passes through the substrate. Therefore, white display is performed.

FIG. 33B is a schematic cross-sectional view when no voltage is applied to the first electrode 3405 and the second electrode 3406. FIG. Since the liquid crystal molecules are aligned vertically, the light from the backlight is not affected by the birefringence of the liquid crystal molecules. Since the first polarizing plate 3403 and the second polarizing plate 3404 are arranged in crossed Nicols, the light from the backlight does not pass through the substrate. Therefore, black display is performed. This is the so-called normally black mode.

By controlling the voltage applied to the first electrode 3405 and the second electrode 3406, it is possible to control the state of the liquid crystal molecules, that is, the orientation. Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

The liquid crystal display device having the structure shown in FIGS. 34A and 34B can perform full-color display by providing a color filter. A color filter can be provided on the first substrate 3401 side or the second substrate 3402 side.

A known liquid crystal material may be used for the VA mode.

FIGS. 33C and 33D show schematic cross-sectional views of the MVA mode. The MVA mode is a method of mutually compensating the viewing angle dependence of each part.

A liquid crystal layer 3410 is sandwiched between a first substrate 3411 and a second substrate 3412 which are arranged to face each other. A first electrode 3415 is formed on the upper surface of the first substrate 3411 . A second electrode 3416 is formed on the upper surface of the second substrate 3412 . A first projection 3417 is formed on the first electrode 3415 for orientation control. A second projection 3418 is formed on the second electrode 3416 for orientation control. A first polarizing plate 3413 is arranged on the side of the first substrate 3411 opposite to the liquid crystal layer. second substrate 3
A second polarizing plate 3414 is arranged on the side of 412 opposite to the liquid crystal layer. Note that the first polarizing plate 3413 and the second polarizing plate 3414 are arranged so as to form crossed Nicols.

The first polarizing plate 3413 may be arranged on the top surface of the first substrate 3411 . A second polarizer 3414 may be placed on top of the second substrate 3412 .

At least one (or both) of the first electrode 3415 and the second electrode 3416 should be translucent (transmissive or reflective). Alternatively, both electrodes may be translucent and part of one electrode may be reflective (transflective).

FIG. 33C is a schematic cross-sectional view when a voltage is applied to the first electrode 3415 and the second electrode 3416 (referred to as a vertical electric field method). Light from the backlight is affected by the birefringence of the liquid crystal molecules. Since the first polarizing plate 3413 and the second polarizing plate 3414 are arranged in crossed Nicols, the light from the backlight passes through the substrate. Therefore, white display is performed. In addition, the liquid crystal molecules form the first projection 3417 and the second projection 341
8, and falls side by side with respect to the first protrusion 3417 and the second protrusion 3418 . Therefore, it is possible to further improve the viewing angle.

FIG. 33D is a schematic cross-sectional view when no voltage is applied to the first electrode 3415 and the second electrode 3416. FIG. Since the liquid crystal molecules are aligned vertically, the light from the backlight is not affected by the birefringence of the liquid crystal molecules. Since the first polarizing plate 3413 and the second polarizing plate 3414 are arranged in crossed Nicols, the light from the backlight does not pass through the substrate. Therefore, black display is performed. This is the so-called normally black mode.

By controlling the voltage applied to the first electrode 3415 and the second electrode 3416, the state, that is, the orientation of the liquid crystal molecules can be controlled. Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

A liquid crystal display device having the structure shown in FIGS. 36C and 36D can perform full-color display by providing a color filter. A color filter can be provided on the first substrate 3411 side or the second substrate 3412 side.

A known liquid crystal material may be used for the MVA mode.

FIGS. 34A and 34B show schematic diagrams of cross sections in the OCB mode. In the OCB mode, the alignment of liquid crystal molecules in the liquid crystal layer forms an optically compensated state, so viewing angle dependency is small. This state of liquid crystal molecules is called bend alignment.

A liquid crystal layer 3500 is sandwiched between a first substrate 3501 and a second substrate 3502 which are arranged to face each other. A first electrode 3505 is formed on the upper surface of the first substrate 3501 . A second electrode 3506 is formed on the upper surface of the second substrate 3502 . A first polarizing plate 3503 is arranged on the side of the first substrate 3501 opposite to the liquid crystal layer. second
A second polarizing plate 336 is arranged on the side of the substrate 3502 opposite to the liquid crystal layer. Note that the first polarizing plate 3503 and the second polarizing plate 336 are arranged so as to form crossed Nicols.

The first polarizing plate 3503 may be arranged on the top surface of the first substrate 3501 . A second polarizer 336 may be placed on top of the second substrate 3502 .

At least one (or both) of the first electrode 3505 and the second electrode 3506 should be translucent (transmissive or reflective). Alternatively, both electrodes may be translucent and part of one electrode may be reflective (transflective).

FIG. 34A is a schematic cross-sectional view when a voltage is applied to the first electrode 3505 and the second electrode 3506 (referred to as a vertical electric field method). Since the liquid crystal molecules are aligned vertically, the light from the backlight is not affected by the birefringence of the liquid crystal molecules. And the first polarizing plate 3503
and the second polarizing plate 336 are arranged in crossed Nicols, light from the backlight does not pass through the substrate. Therefore, black display is performed.

FIG. 34B is a schematic cross-sectional view when no voltage is applied to the first electrode 3505 and the second electrode 3506. FIG. Since the liquid crystal molecules are in a bend alignment state, the light from the backlight is affected by the birefringence of the liquid crystal molecules. Since the first polarizing plate 3503 and the second polarizing plate 336 are arranged in crossed Nicols, the light from the backlight passes through the substrate. Therefore, white display is performed. This is the so-called normally white mode.

By controlling the voltage applied to the first electrode 3505 and the second electrode 3506, the state of the liquid crystal molecules, that is, the orientation can be controlled. Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

The liquid crystal display device having the structure shown in FIGS. 34A and 34B can perform full-color display by providing a color filter. A color filter can be provided on the first substrate 3501 side or the second substrate 3502 side.

A known liquid crystal material may be used for the OCB mode.

FIGS. 34C and 34D show schematic views of cross sections in FLC mode or AFLC mode.

A liquid crystal layer 3510 is sandwiched between a first substrate 3511 and a second substrate 3512 which are arranged to face each other. A first electrode 3515 is formed on the upper surface of the first substrate 3511 . A second electrode 3516 is formed on the upper surface of the second substrate 3512 . A first polarizing plate 3513 is arranged on the side of the first substrate 3511 opposite to the liquid crystal layer. second
A second polarizing plate 3514 is arranged on the side of the substrate 3512 opposite to the liquid crystal layer. note that,
The first polarizing plate 3513 and the second polarizing plate 3514 are arranged so as to form crossed Nicols.

The first polarizing plate 3513 may be arranged on the top surface of the first substrate 3511 . A second polarizer 3514 may be placed on top of the second substrate 3512 .

At least one (or both) of the first electrode 3515 and the second electrode 3516 should be translucent (transmissive or reflective). Alternatively, both electrodes may be translucent and part of one electrode may be reflective (transflective).

FIG. 34C is a schematic cross-sectional view when a voltage is applied to the first electrode 3515 and the second electrode 3516 (referred to as a vertical electric field method). Since the liquid crystal molecules are arranged side by side in a direction deviated from the rubbing direction, the light from the backlight is affected by the birefringence of the liquid crystal molecules. Since the first polarizing plate 3513 and the second polarizing plate 3514 are arranged in crossed Nicols, the light from the backlight passes through the substrate. Therefore, white display is performed.

FIG. 34D is a schematic cross-sectional view when no voltage is applied to the first electrode 3515 and the second electrode 3516. FIG. Since the liquid crystal molecules are aligned horizontally along the rubbing direction, the light from the backlight is not affected by the birefringence of the liquid crystal molecules. And the first polarizing plate 3
Since 513 and second polarizing plate 3514 are arranged in crossed Nicols, light from the backlight does not pass through the substrate. Therefore, black display is performed. This is the so-called normally black mode.

Note that by controlling the voltage applied to the first electrode 3515 and the second electrode 3516, the state of liquid crystal molecules, that is, the orientation can be controlled. Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

A liquid crystal display device having the structure shown in FIGS. 34C and 34D can perform full-color display by providing a color filter. A color filter can be provided on the first substrate 3511 side or the second substrate 3512 side.

A known liquid crystal material may be used for the FLC mode or AFLC mode.

35A and 35B show schematic diagrams of cross sections in the IPS mode. The IPS mode is a mode in which the liquid crystal molecules are always rotated within a plane with respect to the substrate, and employs a lateral electric field method in which electrodes are provided only on one substrate side.

A liquid crystal layer 3600 is sandwiched between a first substrate 3601 and a second substrate 3602 which are arranged to face each other. A first electrode 3605 and a second electrode 3606 are formed on the upper surface of the first substrate 3601 . A first polarizing plate 3603 is arranged on the side of the first substrate 3601 opposite to the liquid crystal layer. A second polarizing plate 3604 is arranged on the side of the second substrate 3602 opposite to the liquid crystal layer. Note that the first polarizing plate 3603 and the second polarizing plate 3604 are arranged so as to form crossed Nicols.

The first polarizing plate 3603 may be arranged on the top surface of the first substrate 3601 . A second polarizer 3604 may be placed on top of the second substrate 3602 .

At least one (or both) of the first electrode 3605 and the second electrode 3606 should be translucent (transmissive or reflective). Alternatively, both electrodes may be translucent and part of one electrode may be reflective (transflective).

FIG. 35A is a schematic cross-sectional view when a voltage is applied to the first electrode 3605 and the second electrode 3606. FIG. Since the liquid crystal molecules are aligned along the electric lines of force that deviate from the rubbing direction, the light from the backlight is affected by the birefringence of the liquid crystal molecules. Since the first polarizing plate 3603 and the second polarizing plate 3604 are arranged in crossed Nicols, the light from the backlight passes through the substrate. Therefore, white display is performed.

FIG. 35B is a schematic cross-sectional view when no voltage is applied to the first electrode 3605 and the second electrode 3606. FIG. Since the liquid crystal molecules are aligned horizontally along the rubbing direction, the light from the backlight is not affected by the birefringence of the liquid crystal molecules. And the first polarizing plate 3
Since 603 and second polarizing plate 3604 are arranged in crossed Nicols, light from the backlight does not pass through the substrate. Therefore, black display is performed. This is the so-called normally black mode.

By controlling the voltage applied to the first electrode 3605 and the second electrode 3606, it is possible to control the state of the liquid crystal molecules, that is, the orientation. Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

The liquid crystal display device having the structure shown in FIGS. 35A and 35B can perform full-color display by providing a color filter. A color filter can be provided on the first substrate 3601 side or the second substrate 3602 side.

A known liquid crystal material may be used for the IPS mode.

FIGS. 35C and 35D show schematic diagrams of cross sections in the FFS mode. The FFS mode is also a mode in which the liquid crystal molecules are always rotated within a plane with respect to the substrate, and adopts a lateral electric field method in which electrodes are provided only on one substrate side.

A liquid crystal layer 3610 is sandwiched between a first substrate 3611 and a second substrate 3612 which are arranged to face each other. A second electrode 3616 is formed on the upper surface of the first substrate 3611 . An insulating film 3617 is formed on the upper surface of the second electrode 3616 . A second electrode 3616 is formed over the insulating film 3617 . A first polarizing plate 3613 is arranged on the side of the first substrate 3611 opposite to the liquid crystal layer. A second polarizing plate 3614 is arranged on the side of the second substrate 3612 opposite to the liquid crystal layer. Note that the first polarizing plate 3613 and the second
and the polarizing plate 3614 are arranged so as to form crossed Nicols.

The first polarizing plate 3613 may be arranged on the top surface of the first substrate 3611 . A second polarizer 3614 may be placed on top of the second substrate 3612 .

At least one (or both) of the first electrode 3615 and the second electrode 3616 should be translucent (transmissive or reflective). Alternatively, both electrodes may be translucent and part of one electrode may be reflective (transflective).

FIG. 35C is a schematic cross-sectional view when voltage is applied to the first electrode 3615 and the second electrode 3616. FIG. Since the liquid crystal molecules are aligned along the electric lines of force that deviate from the rubbing direction, the light from the backlight is affected by the birefringence of the liquid crystal molecules. Since the first polarizing plate 3613 and the second polarizing plate 3614 are arranged in crossed Nicols, the light from the backlight passes through the substrate. Therefore, white display is performed.

FIG. 35D is a schematic cross-sectional view when no voltage is applied to the first electrode 3615 and the second electrode 3616. FIG. Since the liquid crystal molecules are aligned horizontally along the rubbing direction, the light from the backlight is not affected by the birefringence of the liquid crystal molecules. And the first polarizing plate 3
Since 613 and second polarizing plate 3614 are arranged in crossed Nicols, light from the backlight does not pass through the substrate. Therefore, black display is performed. This is the so-called normally black mode.

Note that by controlling the voltage applied to the first electrode 3615 and the second electrode 3616, the state of liquid crystal molecules, that is, the orientation can be controlled. Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

A liquid crystal display device having the structure shown in FIGS. 35C and 35D can perform full-color display by providing a color filter. A color filter can be provided on the first substrate 3611 side or the second substrate 3612 side.

A known liquid crystal material may be used for the FFS mode.

Next, various liquid crystal modes will be described with reference to top views.

FIG. 36 shows a top view of one of a plurality of liquid crystal capacitors of a pixel to which the MVA mode is applied.

FIG. 36 shows a first electrode 3701, second electrodes (3702a, 3702b, 3702c),
and protrusion 3703 are shown. A first electrode 3701 is formed over the entire surface of the opposing substrate. The second electrodes (3702a, 3702b, 3702c
) is formed. Second electrodes (3702a, 3702b, 3702c) are formed on the first electrode 3701 so that the shapes correspond to the second electrodes (3702a, 3702b, 3702c).
) is formed.

The openings in the second electrodes (3702a, 3702b, 3702c) act like protrusions.

When a voltage is applied to the first electrode 3701 and the second electrodes (3702a, 3702b, 3702c) (referred to as a vertical electric field method), liquid crystal molecules are applied to the second electrodes (3702a, 3702b, 3702b,
3702c) and the projection 3703, and fall side by side. Therefore, it is possible to improve the viewing angle. When a pair of polarizing plates are arranged in crossed Nicols, light from the backlight passes through the substrate, so white display is performed.

When no voltage is applied to the first electrode 3701 and the second electrodes (3702a, 3702b, 3702c), the liquid crystal molecules are aligned vertically. When a pair of polarizers are arranged in crossed Nicols, the light from the backlight does not pass through the panel.
A black display is performed. This is the so-called normally black mode.

By controlling the voltage applied to the first electrode 3701 and the second electrodes (3702a, 3702b, and 3702c), the state of the liquid crystal molecules, that is, the orientation can be controlled.
Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

A known liquid crystal material may be used for the MVA mode.

FIGS. 37A, 37B, 37C, and 37D show top views of one liquid crystal capacitor to which the IPS mode is applied. The IPS mode is a mode in which the liquid crystal molecules are always rotated within a plane with respect to the substrate, and employs a lateral electric field method in which electrodes are provided only on one substrate side.

In the IPS mode, a pair of electrodes are formed to have different shapes.

FIG. 37A shows a first electrode 3801 and a second electrode 3802. FIG. The first electrode 3801 and the second electrode 3802 are wave-shaped.

FIG. 37B shows a first electrode 3811 and a second electrode 3812. FIG. The first electrode 3811 and the second electrode 3812 are shaped to have concentric openings.

FIG. 37C shows a first electrode 3831 and a second electrode 3832. FIG. The first electrode 3831 and the second electrode 3832 are comb-shaped and partially overlapped.

FIG. 37D shows a first electrode 3841 and a second electrode 3842. FIG. The first electrode 3841 and the second electrode 3842 are in the form of a comb field and are shaped so that the electrodes are engaged with each other.

First electrodes (3801, 3811, 3821, 3831) and second electrodes (3802, 3
812, 3822, 3832), the liquid crystal molecules are oriented along the electric lines of force deviated from the rubbing direction. When the pair of polarizing plates are arranged in crossed Nicols, the light from the backlight passes through the substrate, so white display is performed.

First electrodes (3801, 3811, 3821, 3831) and second electrodes (3802, 3
812, 3822, 3832), the liquid crystal molecules are aligned horizontally along the rubbing direction. When a pair of polarizing plates are arranged in crossed Nicols, light from the backlight does not pass through the substrate, resulting in black display. This is the so-called normally black mode.

By controlling the voltage applied to the first electrode and the second electrode, it is possible to control the state of the liquid crystal molecules, that is, the orientation. Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

A known liquid crystal material may be used for the IPS mode.

FIGS. 38A, 38B, 38C, and 38D show top views of one liquid crystal capacitor to which the FFS mode is applied. The FFS mode is a mode in which the liquid crystal molecules are always rotated within a plane with respect to the substrate, and employs a lateral electric field method in which electrodes are provided only on one substrate side.

In the FFS mode, the first electrodes are formed in various shapes on top of the second electrodes.

FIG. 38A shows a first electrode 3901 and a second electrode 3902. FIG. The first electrode 3901 has a bent dogleg shape. The second electrode 3902 may be unpatterned.

FIG. 38B shows a first electrode 3911 and a second electrode 3912. FIG. The first electrode 3911 has a concentric shape. The second electrode 3912 may be unpatterned.

FIG. 38C shows a first electrode 3931 and a second electrode 3932. FIG. The first electrode 3931 has a comb-like shape such that the electrodes are engaged with each other. The second electrode 3932 may be unpatterned.

FIG. 38D shows a first electrode 3941 and a second electrode 3942. FIG. The first electrode 3941 has a comb field shape. The second electrode 3942 may be unpatterned.

The first electrodes (3901, 3911, 3921, 3931) and the second electrodes (3902, 3902, 3931)
912, 3922, 3932), the liquid crystal molecules are oriented along the electric lines of force deviated from the rubbing direction. When the pair of polarizing plates are arranged in crossed Nicols, the light from the backlight passes through the substrate, so white display is performed.

The first electrodes (3901, 3911, 3921, 3931) and the second electrodes (3902, 3902, 3931)
912, 3922, 3932), the liquid crystal molecules are aligned horizontally along the rubbing direction. When a pair of polarizing plates are arranged in crossed Nicols, light from the backlight does not pass through the substrate, resulting in black display. This is the so-called normally black mode.

By controlling the voltage applied to the first electrode and the second electrode, it is possible to control the state of the liquid crystal molecules, that is, the orientation. Therefore, since the light from the backlight can be controlled by the liquid crystal molecules, it is possible to display a predetermined image.

A known liquid crystal material may be used for the IPS mode.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each figure of this embodiment is applied or combined with the content (may be part of) described in the figures of other embodiments and examples. , or can be freely replaced. Furthermore, in the drawings of this embodiment, more drawings can be formed by combining parts of other embodiments and examples with respect to each part.

In this embodiment, the contents (or part of them) described in other embodiments and examples are
Example of implementation, example of slight modification, example of partial change, example of improvement, example of detailed description, example of application, example of related parts etc. Therefore, the contents described in other embodiments and examples can be freely applied to, combined with, or replaced with this embodiment.

(Embodiment 8)
In this embodiment, the peripheral portion of the liquid crystal panel will be described.

FIG. 39 shows a backlight unit 2601 called an edge light type and a liquid crystal panel 26.
07 shows an example of a liquid crystal display device. The edge-light type is a type in which a light source is arranged at the end of a backlight unit and light emitted from the light source is emitted from the entire light-emitting surface. The edge-light backlight unit is thin and can save power.

The backlight unit 2601 includes a diffuser plate 2602, a light guide plate 2603, a reflector plate 2604,
It is composed of a lamp reflector 2605 and a light source 2606 .

The light source 2606 has a function of emitting light as required. For example, a cold cathode tube, a hot cathode tube, a light emitting diode, an inorganic EL, an organic EL, or the like is used as the light source 2606 . Lamp reflector 2605 has a function of efficiently guiding light emitted from light source 2606 to light guide plate 2603 . The light guide plate 2603 has a function of totally reflecting the light from the light source 2603 and guiding the light over the entire surface. The diffusion plate 2602 has a function of reducing brightness unevenness. The reflector 2604 is
It has a function of reflecting light leaking from the light guide plate 2603 in the opposite direction from the liquid crystal panel 2603 and reusing it.

A control circuit for adjusting the brightness of the light source 2606 is connected to the backlight unit 2601 . This control circuit allows the brightness of the light source 2606 to be adjusted.

FIGS. 40A, 40B, 40C, and 40D are diagrams showing detailed configurations of edge-light type backlight units. Descriptions of the diffusion plate, the light guide plate, the reflection plate, and the like are omitted.

A backlight unit 2701 shown in FIG. 40A has a structure using a cold cathode tube 2703 as a light source. A lamp reflector 2702 is provided to efficiently reflect the light from the cold cathode tube 2703 . Such a configuration is often used in large display devices.

A backlight unit 2711 shown in FIG. 40B includes a light emitting diode (LE) as a light source.
D) A configuration using 2713. For example, a light-emitting diode (W) 2713 that emits white light
are arranged at predetermined intervals. A lamp reflector 2712 is provided to efficiently reflect the light from the light emitting diode 2713 .

Since the emission intensity of the light emitting diode is high, the structure using the light emitting diode is suitable for a large display device. In addition, since the light-emitting diode has excellent color reproducibility, it is possible to display an image that is faithful to the input image information. Moreover, since the light-emitting diode is small, the layout area can be reduced. Therefore, the frame of the display device can be narrowed.

In addition, when the light-emitting diode is mounted on a large-sized display device, the light-emitting diode can be arranged on the back surface of the substrate. The light-emitting diodes maintain a predetermined interval, and the light-emitting diodes of each color are arranged in order.

A backlight unit 2721 shown in FIG. 40C includes light emitting diodes (LEDs) 2723, light emitting diodes (LEDs) 2724, and light emitting diodes (LEs) of RGB colors as light sources.
D) A configuration using 2725. Light-emitting diodes 2723 (LED), light-emitting diodes (LED) 2724, and light-emitting diodes (LED) 2725 of RGB colors are arranged at predetermined intervals. Color reproducibility can be improved by using light emitting diodes (LED) 2723, light emitting diodes (LED) 2724, and light emitting diodes (LED) 2725 of RGB colors. Also, a lamp reflector 2722 is provided to efficiently reflect the light from the light emitting diode.

Since light-emitting diodes have high luminance, a configuration using light-emitting diodes of each color of RGB as a light source is suitable for a large-sized display device. In addition, since the light-emitting diode has excellent color reproducibility, it is possible to display an image that is faithful to the input image information. Moreover, since the light-emitting diode is small, the layout area can be reduced. Therefore, the frame of the display device can be narrowed.

Color display can be performed by sequentially lighting the RGB light-emitting diodes according to time. It can be displayed in a so-called field sequential mode.

Note that a light emitting diode emitting white light and a light emitting diode (LED) 2723 of each color of RGB
, light emitting diodes (LEDs) 2724 and light emitting diodes (LEDs) 2725 can be combined.

In addition, when the light-emitting diode is mounted on a large-sized display device, the light-emitting diode can be arranged on the back surface of the substrate. Also, each of the light emitting diodes maintains a predetermined interval, and the light emitting diodes of each color are arranged in order. Such an arrangement can improve color reproducibility.

A backlight unit 2731 shown in FIG. 40(D) includes light emitting diodes (LEDs) 2733, light emitting diodes (LEDs) 2734, and light emitting diodes (LEs) of RGB colors as light sources.
D) A configuration using 2735. For example, light-emitting diodes (LEDs) 27 of RGB colors
33, light-emitting diodes (LEDs) 2734 and light-emitting diodes (LEDs) 2735, a plurality of light-emitting diodes (LEDs) 2734 in FIG. With such a configuration, the color reproducibility can be further improved. Also, a lamp reflector 2732 is provided to efficiently reflect the light from the light emitting diode.

Since light emitting diodes have a high emission intensity, a configuration using light emitting diodes of each color of RGB as a light source is suitable for a large display device. In addition, since the light-emitting diode has excellent color reproducibility, it is possible to display an image that is faithful to the input image information. Moreover, since the light-emitting diode is small, the layout area can be reduced. Therefore, the frame of the display device can be narrowed.

Color display can be performed by sequentially lighting the RGB light-emitting diodes according to time.

Note that a light emitting diode emitting white light and a light emitting diode (LED) 2733 of each color of RGB
, light emitting diodes (LEDs) 2734 and light emitting diodes (LEDs) 2735 can be combined.

In addition, when the light-emitting diode is mounted on a large-sized display device, the light-emitting diode can be arranged on the back surface of the substrate. Each of the light emitting diodes maintains a predetermined distance, and the light emitting diodes of each color are arranged in order. Such an arrangement can improve color reproducibility.

FIG. 41A shows a backlight unit 2800 called a direct type and a liquid crystal panel 280.
5 shows an example of a liquid crystal display device having . The direct type is a method in which a light source is arranged directly below a light emitting surface so that light emitted from the light source is emitted from the entire light emitting surface. The direct type backlight unit can efficiently use the amount of emitted light.

A backlight unit 2800 is composed of a diffusion plate 2801 , a light shielding plate 2802 , a lamp reflector 2803 and a light source 2804 .

The light source 2804 has a function of emitting light as required. For example, a cold cathode tube, a hot cathode tube, a light emitting diode, an inorganic EL, an organic EL, or the like is used as the light source 2805 . The lamp reflector 2803 efficiently diffuses the light emitted from the light source 2804 to the diffusion plate 2801 and the light shielding plate 2 .
It has the function of leading to 802. The light shielding plate 2802 has a function of reducing unevenness in lightness by increasing light shielding in accordance with the arrangement of the light sources 2804 as the light intensity increases. Diffusion plate 2801
has the function of further reducing brightness unevenness.

A control circuit for adjusting the brightness of the light source 2804 is connected to the backlight unit 2800 . This control circuit allows the brightness of the light source 2804 to be adjusted.

FIG. 41B shows a backlight unit 3015 called a direct type and a liquid crystal panel 301.
0 shows an example of a liquid crystal display device.

The backlight unit 2810 includes a diffuser plate 2811, a light shielding plate 2812, a lamp reflector 2813, a light source (R) 2814a for each color of RGB, a light source (G) 2814b, and a light source (B) 2814b.
814c.

The light source 2814a (R), the light source 2814b (G), and the light source 2814c (B) for each color of RGB have a function of emitting light as necessary. For example, light source 2814a (R), light source 2814b
As (G) and the light source 2814c (B), a cold cathode tube, a hot cathode tube, a light emitting diode, an inorganic EL, an organic EL, or the like is used. The lamp reflector 2813 has a function of efficiently guiding the light emitted from the light source 2814 to the diffusion plate 2811 and the light shielding plate 2812 . The light shielding plate 2812 is
It has a function of reducing unevenness in lightness by increasing light shielding in areas where the light is stronger in accordance with the arrangement of the light sources 2814 . The diffuser plate 2811 further has a function of reducing brightness unevenness.

The backlight unit 2810 includes a light source 2814a (R) for each color of RGB, a light source 2
A control circuit is connected to adjust the brightness of 814b (G) and light source 2814c (B). With this control circuit, light sources 2814a (R) and light sources 2814b (G
) and light source 2814c (B) can be adjusted.

FIG. 42 is a diagram showing an example of the configuration of a polarizing plate (also referred to as a polarizing film).

The polarizing film 2900 has a protective film 2901 , a substrate film 2902 , a PVA polarizing film 2903 , a substrate film 2904 , an adhesive layer 2905 and a release film 2906 .

The PVA polarizing film 2903 has a function of converting light into light only in a certain vibration direction (linearly polarized light). Specifically, the PVA polarizing film 2903 contains molecules (polarizers) in which electron densities are significantly different between vertical and horizontal directions. The PVA polarizing film 2903 in which the directions of the molecules with which the density of electrons differs greatly in the vertical direction and the horizontal direction are aligned makes it possible to obtain linearly polarized light.

As an example, the PVA polarizing film 2903 is made of polyvinyl alcohol (Poly Vin
yl Alcohol) polymer film is doped with an iodine compound and the PVA film is pulled in a certain direction to obtain a film in which iodine molecules are aligned in a certain direction. Light parallel to the long axis of the iodine molecule is absorbed by the iodine molecule. For high durability applications and high heat resistance applications, a dichroic dye may be used instead of iodine. In addition, the dye
It is suitable for liquid crystal display devices such as in-vehicle LCDs and projector LCDs that require durability and heat resistance.

In addition, the PVA polarizing film 2903 has a base film (substrate film 290) on both sides.
2 and substrate film 2904), the reliability can be increased. In addition, PVA
The polarizing film 2903 may be sandwiched between triacetylulose (TAC) films having high transparency and high durability. Such substrate films and TAC films are P
It functions as a protective layer for the polarizer that the VA polarizing film 2903 has.

A substrate film (substrate film 2904) is attached with an adhesive layer 2905 for attachment to the glass substrate of the liquid crystal panel. The adhesive layer 2905 is formed by applying an adhesive to the substrate film (substrate film 2904) on one side. The adhesive layer 2905 is provided with a release film 2906 (separate film).

A protective film 2901 is provided on the other substrate film (substrate film 2902).

A hard coat scattering layer (antiglare layer) may be provided on the surface of the polarizing film 2900 . The hard coat scattering layer has fine irregularities formed on its surface by AG treatment and has an anti-glare function that scatters external light, so that external light can be prevented from being reflected on the liquid crystal panel. Therefore, surface reflection can be prevented.

In addition, a plurality of optical thin film layers having different refractive indices may be multilayered (also referred to as antireflection treatment or AR treatment) on the surface of the polarizing film 2900 . A plurality of optical thin film layers having different refractive indices can reduce the reflectance of the surface due to the interference effect of light.

FIG. 43 is a diagram showing an example of system blocks of a liquid crystal display device.

As shown in FIG. 43A, in the pixel portion 3005, a signal line 3012 is connected to the signal line driver circuit 300.
3 and is arranged to extend. Further, scanning lines 3010 are arranged extending from the scanning line driving circuit 3004 . A plurality of pixels are arranged in a matrix in intersection regions between the signal lines 3012 and the scanning lines 3010 . Note that each of the plurality of pixels has a switching element, and the details of the pixel portion 3005 have been described in the above embodiment, and therefore are omitted here.

In FIG. 43A, a driver circuit portion 3008 includes a control circuit 3002, a signal line driver circuit 30
03 and a scanning line driving circuit 3004 . A video signal 3001 is input to the control circuit 3002 . The control circuit 3002 controls the signal line driving circuit 30 according to this control signal 3001 .
03 and the scanning line driving circuit 3004 are controlled. Therefore, the control circuit 3002 inputs respective control signals to the signal line driver circuit 3003 and the scanning line driver circuit 3004 . Then, according to this control signal, the signal line driving circuit 3003 inputs the video signal to the signal line 3012,
The scanning line driver circuit 3004 inputs scanning signals to the scanning lines 3010 . A switching element included in the pixel is selected according to the scanning signal, and a video signal is input to the pixel electrode of the pixel.

Note that the control circuit 3002 also controls the power supply 3007 according to the control signal 3001 . Note that the power source 3007 has means for supplying power to the lighting means 3006 . illumination means 30
06 can be an edge light type backlight unit or a direct type backlight unit. Also, a front light may be used as the lighting means 3006 . A front light is a plate-like light unit that is attached to the front side of the pixel portion and that is composed of a light emitter and a light guide that illuminate the entire area. Such a lighting means can evenly illuminate the pixel portion with low power consumption.

The scanning line driving circuit 3004 includes, for example, a shift register 3041 as shown in FIG.
It has a circuit functioning as a level shifter 3042 and a buffer 3043 . Signals such as a gate start pulse (GSP) and a gate clock signal (GCK) are input from the control circuit 2902 to the shift register 3041 .

As shown in FIG. 43C, the signal line driver circuit 3003 has circuits functioning as a shift register 3031 , a first latch 3032 , a second latch 3033 , a level shifter 3034 , and a buffer 3035 . A circuit functioning as the buffer 3035 is a circuit having a function of amplifying a weak signal, and includes an operational amplifier or the like. The level shifter 3034 receives signals such as a start pulse (SSP) and a source clock signal (SCK) from the first latch 303 .
2 is input with data (DATA) such as a video signal. A latch (LAT) signal can be temporarily held in the second latch 3033 and input to the pixel portion 3005 all at once. This is called line sequential driving. Therefore, if the pixels are dot-sequentially driven instead of line-sequentially driven,
A second latch may not be required.

In this embodiment, a known liquid crystal panel can be used. For example, a structure in which a liquid crystal layer is sealed between two substrates can be used as a liquid crystal panel.
A transistor, a capacitor, a pixel electrode, an alignment film, or the like is formed over one substrate. A polarizing plate, a retardation plate, or a prism sheet may be arranged on the side opposite to the upper surface of the substrate. A color filter, a black matrix, a counter electrode, an alignment film, and the like are formed on the other substrate. A polarizing plate or a retardation plate may be arranged on the side opposite to the upper surface of the other substrate. Note that the color filters and the black matrix may be formed on the top surface of one of the substrates. Note that three-dimensional display can be performed by arranging a slit (lattice) on the upper surface side of one of the substrates or on the opposite side thereof.

A polarizing plate, a retardation plate, and a prism sheet can each be placed between two substrates. Alternatively, it can be integral with either of the two substrates.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each figure of this embodiment is applied or combined with the content (may be part of) described in the figures of other embodiments and examples. , or can be freely replaced. Furthermore, in the drawings of this embodiment, more drawings can be formed by combining parts of other embodiments and examples with respect to each part.

In this embodiment, the contents (or part of them) described in other embodiments and examples are
Example of implementation, example of slight modification, example of partial change, example of improvement, example of detailed description, example of application, example of related parts etc. Therefore, the contents described in other embodiments and examples can be freely applied to, combined with, or replaced with this embodiment.

(Embodiment 9)
In this embodiment, a method for driving a display device will be described. In particular, a method for driving a liquid crystal display device will be described.

A liquid crystal panel that can be used in the liquid crystal display device described in this embodiment has a structure in which a liquid crystal material is sandwiched between two substrates. The two substrates each have electrodes for controlling the electric field applied to the liquid crystal material. A liquid crystal material is a material whose optical and electrical properties are changed by an externally applied electric field. Therefore, the liquid crystal panel
It is a device in which desired optical and electrical properties can be obtained by controlling the voltage applied to the liquid crystal material using the electrodes of the substrate. By arranging a large number of electrodes two-dimensionally to form pixels and individually controlling voltages applied to the pixels, a liquid crystal panel capable of displaying a fine image can be obtained.

Here, the response time of the liquid crystal material to changes in the electric field is the distance between the two substrates (cell gap)
And, depending on the type of liquid crystal material, etc., it is generally several milliseconds to several tens of milliseconds. Furthermore, the response time of the liquid crystal material is even longer when the change in electric field is small. This property causes image display problems such as afterimages, trailing, and contrast reduction when displaying moving images on the liquid crystal panel. is small), the degree of the aforementioned disturbance becomes significant.

On the other hand, a problem specific to liquid crystal panels using an active matrix is a change in write voltage due to constant charge driving. The constant charge drive in this embodiment will be described below.

A pixel circuit in an active matrix includes a switch that controls writing and a capacitive element that holds charges. A method of driving a pixel circuit in an active matrix is to turn on a switch to write a predetermined voltage into the pixel circuit, and then immediately turn off the switch to hold the charge in the pixel circuit (hold state). In the hold state, no charge is exchanged between the inside and the outside of the pixel circuit (constant charge). Normally, the period in which the switch is in the off state is about several hundred (the number of scanning lines) times longer than the period in which the switch is in the on state. Therefore, it can be considered that most of the switches in the pixel circuit are in an off state.
As described above, constant charge driving in the present embodiment is a driving method in which the pixel circuit is in the hold state for most of the period when the liquid crystal panel is driven.

Next, the electrical properties of the liquid crystal material will be described. When the electric field applied from the outside changes, the liquid crystal material changes not only in its optical properties but also in its dielectric constant. That is, when each pixel of the liquid crystal panel is considered as a capacitive element (liquid crystal element) sandwiched between two electrodes, the capacitive element is a capacitive element whose capacitance changes depending on the applied voltage. This phenomenon is called dynamic capacitance.

When the capacitive element whose capacitance changes with the applied voltage is driven by the constant charge driving described above, the following problems arise. That is, there is a problem that when the electrostatic capacitance of the liquid crystal element changes in the hold state in which charge is not transferred, the applied voltage also changes. This can be understood from the fact that the amount of charge is constant in the relational expression of (amount of charge)=(capacitance)×(applied voltage).

For the above reasons, in the liquid crystal panel using the active matrix, the voltage in the hold state changes from the voltage in writing due to constant charge driving. As a result, the transmittance of the liquid crystal element is different from the change in the drive method without the hold state. FIG. 44 shows this situation. FIG. 44A shows an example of controlling the voltage written to the pixel circuit, with the horizontal axis representing time and the vertical axis representing the absolute value of the voltage. FIG. 44B shows an example of control of the voltage written to the pixel circuit when the horizontal axis represents time and the vertical axis represents voltage. In FIG. 44(C), the horizontal axis represents time and the vertical axis represents the transmittance of the liquid crystal element.
44A and 44B show changes over time in the transmittance of the liquid crystal element when the voltage shown in FIG. 44A or 44B is written to the pixel circuit. In FIGS. 44A to 44C, period F represents a voltage rewriting cycle, and voltage rewriting times are t ₁ , t ₂ , t ₃ , t ₄ , .
・Explain as

Here, _the write voltage corresponding to _the image data input to the liquid crystal display _device is |V ₁ | for rewriting at time ₀ , and |
Let V ₂ | (See FIG. 44(A))

The polarity of the write voltage corresponding to the image data input to the liquid crystal display device may be changed periodically. (Reversal drive: see FIG. 44B) By this method, it is possible to avoid applying a DC voltage to the liquid crystal as much as possible, so that burn-in or the like due to deterioration of the liquid crystal element can be prevented. It should be noted that the cycle of switching the polarity (reversal cycle) may be the same as the voltage rewriting cycle. In this case, since the inversion cycle is short, it is possible to reduce the occurrence of flicker due to inversion driving. Furthermore, the inversion period may be an integral multiple of the voltage rewriting period. In this case, the inversion period is long, and the frequency of writing the voltage by changing the polarity can be reduced, so that power consumption can be reduced.

FIG. 44C shows changes in the transmittance of the liquid crystal element with time when the voltage shown in FIG. 44A or 44B is applied to the liquid crystal element. Here, a voltage |V ₁ is applied to the liquid crystal element
| is applied and the transmittance of the liquid crystal element after a sufficient time has passed is _TR1 . Similarly, a voltage |V ₂ | is applied to the liquid crystal element, and the transmittance of the liquid crystal element after a sufficient amount of time has passed is TR ₂ . At time _t1 , when the voltage applied to the liquid crystal element changes from | _V1 | to | _V2 |, the transmittance of the liquid crystal element does not immediately become _TR2 as indicated by the dashed line 30401. change slowly. For example, when the voltage rewrite period is the same as the frame period (16.7 milliseconds) of the image signal of 60 Hz, it takes about several frames until the transmittance changes to _TR2 .

However, the smooth temporal change in transmittance as indicated by the dashed line 30401 is obtained when the voltage |V ₂ | is accurately applied to the liquid crystal element. In an actual liquid crystal panel, for example, a liquid crystal panel using an active matrix, constant charge driving causes the voltage in the hold state to change from the voltage in writing. does not change with time as shown in , but instead changes with time as indicated by a solid line 30402 in stages. This is because the constant charge drive causes the voltage to change, so that the target voltage cannot be reached in one write operation. As a result, the response time of the transmittance of the liquid crystal element is apparently longer than the original response time (broken line 30401), and the image display problems such as afterimages, tailing, and contrast reduction are conspicuous. It will cause it.

By using overdrive driving, it is possible to simultaneously solve the problem of the inherently long response time of the liquid crystal element and the phenomenon that the apparent response time is further lengthened due to insufficient writing due to dynamic capacitance and constant charge driving. FIG. 45 shows this situation. FIG. 45A shows an example of controlling the voltage written to the pixel circuit, with the horizontal axis representing time and the vertical axis representing the absolute value of the voltage. FIG. 45B shows an example of control of the voltage written to the pixel circuit when the horizontal axis represents time and the vertical axis represents voltage. In FIG. 45C, the horizontal axis represents time and the vertical axis represents the transmittance of the liquid crystal element. FIG. It represents the time change of transmittance. In FIGS. 45A to 45C, a period F represents a voltage rewriting cycle, and voltage rewriting times are t ₁ , t ₂ , t ₃ , t ₄ , . . . .

Here, the write voltage corresponding to the image data input to the liquid crystal display device is |V ₁ | for rewriting at time 0, |V ₃ | for rewriting at time t ₁ , time t ₂ , t ₃ , t
₄ , . . . is |V ₂ |. (See FIG. 45(A))

The polarity of the write voltage corresponding to the image data input to the liquid crystal display device may be changed periodically. (Reversal drive: see FIG. 45B) By this method, it is possible to avoid applying a DC voltage to the liquid crystal as much as possible, so that burn-in or the like due to deterioration of the liquid crystal element can be prevented. It should be noted that the cycle of switching the polarity (reversal cycle) may be the same as the voltage rewriting cycle. In this case, since the inversion cycle is short, it is possible to reduce the occurrence of flicker due to inversion driving. Furthermore, the inversion period may be an integral multiple of the voltage rewriting period. In this case, the inversion period is long, and the frequency of writing the voltage by changing the polarity can be reduced, so that power consumption can be reduced.

FIG. 45C shows changes in the transmittance of the liquid crystal element with time when the voltage shown in FIG. 45A or 45B is applied to the liquid crystal element. Here, a voltage |V ₁ is applied to the liquid crystal element
| is applied and the transmittance of the liquid crystal element after a sufficient time has passed is _TR1 . Similarly, a voltage |V ₂ | is applied to the liquid crystal element, and the transmittance of the liquid crystal element after a sufficient amount of time has passed is TR ₂ . Similarly, a voltage |V ₃ | is applied to the liquid crystal element, and the transmittance of the liquid crystal element after a sufficient amount of time has passed is TR ₃ . At time t ₁ , the voltage applied to the liquid crystal element changes from |V ₁ | to |V
₃ |, the transmittance of the liquid crystal element tries to change to TR ₃ over several frames, as indicated by the dashed line 30501 . However, the application of the voltage |V ₃ | ends at time t ₂ and after time t ₂ the voltage |V ₂ | is applied. Therefore, the transmittance of the liquid crystal element is not as indicated by the dashed line 30501 but as indicated by the solid line 30502 . here,
It is preferable to set the value of the voltage |V ₃ | so that the transmittance is approximately TR ₂ at time t ₂ . Here, the voltage |V ₃ | is also called an overdrive voltage.

That is, the response time of the liquid crystal element can be controlled to some extent by changing the overdrive voltage |V ₃ |. This is because the response time of the liquid crystal changes depending on the strength of the electric field. Specifically, the stronger the electric field, the shorter the response time of the liquid crystal element, and the weaker the electric field, the longer the response time of the liquid crystal element.

The overdrive voltage |V ₃ | is preferably changed according to the amount of voltage change, that is, the voltages |V ₁ | and |V ₂ | that give the desired transmittances TR ₁ and TR ₂ . . This is because even if the response time of the liquid crystal element changes depending on the amount of voltage change, the optimum response time can always be obtained by changing the overdrive voltage |V ₃ | accordingly. be.

The overdrive voltage |V ₃ | is preferably changed according to the liquid crystal mode such as TN, VA, IPS, and OCB. This is because even if the response speed of the liquid crystal varies depending on the mode of the liquid crystal, the optimum response time can always be obtained by changing the overdrive voltage |V ₃ | accordingly.

Note that the voltage rewrite cycle F may be the same as the frame cycle of the input signal. In this case, since the peripheral driving circuit of the liquid crystal display device can be simplified, the liquid crystal display device can be manufactured at low cost.

Note that the voltage rewriting period F may be shorter than the frame period of the input signal. for example,
The voltage rewriting period F may be 1/2 times the frame period of the input signal, 1/3 times, or less. It is effective to use this method in combination with measures against deterioration of moving image quality caused by hold driving of the liquid crystal display device, such as black insertion driving, backlight blinking, backlight scanning, and intermediate image insertion driving by motion compensation. be. That is, since the required response time of the liquid crystal element is short, measures against deterioration in moving image quality caused by the hold driving of the liquid crystal display device can be made relatively easily by using the overdrive driving method described in this embodiment. can shorten the response time of the liquid crystal element. Although it is possible to substantially shorten the response time of a liquid crystal element by adjusting the cell gap, liquid crystal material, liquid crystal mode, etc., it is technically difficult. Therefore, it is very important to use a driving method such as overdrive that shortens the response time of the liquid crystal element.

Note that the voltage rewriting period F may be longer than the frame period of the input signal. for example,
The voltage rewriting period F may be twice the frame period of the input signal, may be three times, or may be longer than that. It is effective to use this method together with means (circuit) for determining whether or not the voltage is not rewritten for a long period of time. That is, when the voltage is not rewritten for a long period of time, the operation of the circuit can be stopped during that period by not performing the voltage rewriting operation itself, so that a liquid crystal display device with low power consumption can be obtained. can be done.

Next, a specific method for changing the overdrive voltage |V ₃ | according to the voltages |V ₁ | and |V ₂ | that give the desired transmittances TR ₁ and TR ₂ will be described.

The overdrive circuit is a circuit for appropriately controlling the overdrive voltage |V ₃ | according to the voltages |V ₁ | and |V ₂ | that give the desired transmittances TR ₁ and TR ₂ . The signal input to the drive circuit is the _voltage |V
₁ | and a signal related to the voltage |V ₂ | that gives the transmittance TR ₂ , and the signal output from the overdrive circuit is a signal related to the overdrive voltage |V ₃ |. Here, these signals include the voltages (|V ₁ |, |V ₂ |
, |V ₃ |), or a digital signal for applying a voltage to the liquid crystal element. Here, it is assumed that the signal related to the overdrive circuit is a digital signal.

First, referring to FIG. 46A, the overall configuration of the overdrive circuit will be described. Here, the input image signal 310 is used as a signal for controlling the overdrive voltage.
1a and 3101b are used. Assume that as a result of processing these signals, an output image signal 3104 is output as a signal that gives an overdrive voltage.

Here, the voltages |V ₁ | and |V ₂ | that give the desired transmittances TR ₁ and TR ₂ are
Since the input image signals 3101a and 3101b are image signals in frames adjacent to each other, it is preferable that the input image signals 3101a and 3101b are also image signals in frames adjacent to each other. In order to obtain such a signal, the input image signal 3101a can be input to the delay circuit 3102 in FIG. 46A, and the resulting output signal can be used as the input image signal 3101b. Delay circuit 3102 may be, for example, a memory. i.e.
In order to delay the input image signal 3101a by one frame, the input image signal 3101a is stored in the memory.
101a is stored, and at the same time, the signal stored in the previous frame is taken out from the memory as the input image signal 3101b, and the input image signal 3101a and the input image signal 3101b are input to the correction circuit 3103 at the same time. By doing so, it is possible to handle image signals in frames adjacent to each other. Then, by inputting the image signals in the frames adjacent to each other to the correction circuit 3103, the output image signal 3104 is
can be obtained. When a memory is used as the delay circuit 3102, it can be a memory (that is, a frame memory) having a capacity capable of storing image signals for one frame in order to delay by one frame. By doing this, without excess or deficiency of memory capacity,
It can have a function as a delay circuit.

Next, the delay circuit 3102 configured mainly for the purpose of reducing memory capacity will be described. By using such a circuit as the delay circuit 3102, the memory capacity can be reduced, so that the manufacturing cost can be reduced.

As the delay circuit 3102 having such characteristics, specifically, one shown in FIG. 46B can be used. A delay circuit 3102 shown in (B) of FIG.
105, a memory 3106, and a decoder 3107.

The operation of the delay circuit 3102 shown in FIG. 46B is as follows. first,
Before the input image signal 3101a is stored in the memory 3106, the encoder 3105 performs compression processing. This can reduce the size of data to be stored in memory 3106 . As a result, the memory capacity can be reduced, so that the manufacturing cost can be reduced. Then, the image signal subjected to the compression processing is processed by the decoder 3107
, where it is decompressed. Thereby, the signal before being compressed by the encoder 3105 can be restored. Here, the compression/decompression processing performed by encoder 3105 and decoder 3107 may be reversible processing. By doing so, the image signal is not degraded even after the compression/decompression process is performed, so that the memory capacity can be reduced without degrading the quality of the image finally displayed on the device. Furthermore, the compression/decompression processing performed by encoder 3105 and decoder 3107 may be irreversible processing. By doing so, the data size of the image signal after compression can be made very small, so that the memory capacity can be greatly reduced.

As a method for reducing the memory capacity, various methods can be used other than the methods mentioned above. Instead of compressing the image with an encoder, the color information contained in the image signal is reduced (for example, from 260,000 colors to 65,000 colors), or the number of data is reduced (reduced resolution). method can be used.

Next, a specific example of the correction circuit 3103 will be described with reference to FIGS. 46(C) to 46(E). A correction circuit 3103 is a circuit for outputting an output image signal having a certain value from two input image signals. Here, if the relationship between the two input image signals and the output image signal is non-linear and difficult to obtain by simple calculation, a lookup table (LUT) may be used as the correction circuit 3103 . In the LUT, the relationship between the two input image signals and the output image signal is obtained in advance by measurement, so the output image signal corresponding to the two input image signals can be obtained simply by referring to the LUT. (See FIG. 46C) By using the LUT 3108 as the correction circuit 3103, the correction circuit 3103 can be realized without complicated circuit design or the like.

Here, since the LUT is one type of memory, it is preferable to reduce the memory capacity as much as possible in order to reduce manufacturing costs. As an example of the correction circuit 3103 for realizing this, the circuit shown in (D) of FIG. 46 can be considered. The correction circuit 3103 shown in (D) of FIG.
It has a LUT 3109 and an adder 3110 . The input image signal 310 is stored in the LUT 3109
1a and the difference data between the output image signal 3104 to be output is stored. That is, from the input image signal 3101a and the input image signal 3101b, the corresponding difference data is extracted from the LUT.
3109, and the extracted difference data and the input image signal 3101a are added to the adder 31
By adding by 10, an output image signal 3104 can be obtained. Note that the LUT
By using difference data as the data stored in the 3109, the memory capacity of the LUT can be reduced. This is because the difference data has a smaller data size than the output image signal 3104 as it is, so the memory capacity required for the LUT 3109 can be reduced.

Furthermore, if the output image signal can be obtained by a simple arithmetic operation such as four arithmetic operations on two input image signals, it can be realized by a combination of simple circuits such as an adder, a subtractor, and a multiplier.
As a result, there is no need to use LUTs, and manufacturing costs can be greatly reduced.
As such a circuit, the circuit shown in (E) of FIG. 46 can be mentioned. (
The correction circuit 3103 shown in E) includes a subtractor 3111, a multiplier 3112, and an adder 3113.
, has First, the subtractor 3111 obtains the difference between the input image signal 3101a and the input image signal 3101b. A multiplier 3112 then multiplies the difference value by an appropriate factor. The input image signal 3101a is multiplied by an appropriate coefficient, and the difference value is added to the adder 311.
By adding by 3, an output image signal 3104 can be obtained. By using such a circuit, the need to use an LUT is eliminated, and manufacturing costs can be greatly reduced.

By using the correction circuit 3103 shown in FIG. 46(E) under certain conditions,
It is possible to prevent the inappropriate output image signal 3104 from being output. That condition is
The difference between the output image signal 3104 that gives the overdrive voltage and the input image signals 3101a and 3101b has linearity. Then, the slope of this linearity is used as a coefficient to be multiplied by the multiplier 3112 . That is, it is preferable to use the correction circuit 3103 shown in FIG. 46(E) for the liquid crystal element having such properties. As a liquid crystal element having such properties, there is an IPS mode liquid crystal element whose response speed is less dependent on gradation. In this way, for example, by using the correction circuit 3103 shown in FIG. 46E in the IPS mode liquid crystal element, the manufacturing cost can be greatly reduced and the output of an inappropriate output image signal 3104 can be prevented. An overdrive circuit can be obtained that can be prevented.

Note that functions equivalent to those of the circuits shown in FIGS. 46A to 46E may be realized by software processing. For the memory used in the delay circuit, other memories in the liquid crystal display device, memory in the device that sends the image displayed on the liquid crystal display device (for example, a video card in a personal computer or similar device), etc. can be reused. By doing so, it is possible not only to reduce the manufacturing cost, but also to allow the user to select the strength of the overdrive, the situation of use, etc. according to his/her preference.

Next, the drive for manipulating the potential of the common line will be described with reference to FIG. (
A) shows a plurality of pixel circuits when one common line is arranged for one scanning line in a display device using a display element having capacitive properties such as a liquid crystal element. It is a diagram. The pixel circuit shown in FIG. 47A includes a transistor 3201, an auxiliary capacitor 3202, a display element 3203, a video signal line 3204, a scanning line 3205, and a common line 3206.

A gate electrode of the transistor 3201 is electrically connected to the scan line 3205, one of the source electrode and the drain electrode of the transistor 3201 is electrically connected to the video signal line 3204, and the other of the source electrode and the drain electrode of the transistor 3201 is electrically connected to the video signal line 3204. is the auxiliary capacity 3202
and one electrode of the display element 3203 .
Also, the other electrode of the auxiliary capacitor 3202 is electrically connected to the common line 3206 .

First, since the transistor 3201 of the pixel selected by the scanning line 3205 is turned on, a voltage corresponding to the video signal is applied to the display element 3203 and the auxiliary capacitor 3202 via the video signal line 3204 . At this time, if the video signal causes all the pixels connected to the common line 3206 to display the lowest gradation, or if the common line 3206
If all the pixels connected to 206 are to display the highest gradation, there is no need to write the video signal to each pixel via the video signal line 3204 . Video signal line 320
4, the voltage applied to the display element 3203 can be changed by changing the potential of the common line 3206 instead of writing the video signal through the .

Next, FIG. 47B shows a display device using a display element having a capacitive property such as a liquid crystal element, in which two common lines are arranged for one scanning line. FIG. 4 is a diagram showing a plurality of pixel circuits; A pixel circuit shown in FIG.
216 and a second common line 3217 .

A gate electrode of the transistor 3211 is electrically connected to the scan line 3215, one of the source electrode and the drain electrode of the transistor 3211 is electrically connected to the video signal line 3214, and the other of the source electrode and the drain electrode of the transistor 3211 is electrically connected to the video signal line 3214. is the auxiliary capacity 3212
and one electrode of the display element 3213 .
Also, the other electrode of the auxiliary capacitor 3212 is electrically connected to the first common line 3216 .
In addition, the other electrode of the auxiliary capacitor 3212 is electrically connected to the second common line 3217 in the pixel adjacent to the pixel.

The pixel circuit shown in FIG. 47B has a small number of pixels electrically connected to one common line.
By moving the potential of 216 or the second common line 3217, the frequency with which the voltage applied to the display element 3213 can be changed remarkably increases. Also, source inversion driving or dot inversion driving becomes possible. By source inversion driving or dot inversion driving, flicker can be suppressed while improving the reliability of the device.

Next, a scanning backlight will be described with reference to FIG. FIG. 66A is a diagram showing a scanning backlight in which cold cathode tubes are juxtaposed. The scanning backlight shown in FIG. 66A includes a diffusion plate 6601 and N cold cathode tubes 6602-1 to 6602-N. By arranging the N cold-cathode tubes 6602-1 to 6602-N side by side behind the diffusion plate 6601, the N cold-cathode tubes 6602-1 to 6602-N can be scanned while changing their brightness. can be done.

A change in brightness of each cold cathode tube during scanning will be described with reference to FIG. 66(C). First, the brightness of the cold cathode tube 6602-1 is changed for a certain period of time. Then, after that, the cold cathode tube 660
The brightness of the cold cathode tube 6602-2 arranged next to 2-1 is changed for the same amount of time. In this way, the cold cathode tubes 6602-1 to 6602-N are sequentially changed in brightness. In addition, in FIG. 66C, the luminance to be changed for a certain period of time is lower than the original luminance, but it may be higher than the original luminance. Also, although the cold cathode tubes 6602-1 to 6602-N are scanned, scanning may be performed in the opposite direction from the cold cathode tubes 6602-N to 6602-1.

By driving as shown in FIG. 66, the average brightness of the backlight can be reduced. Therefore, the power consumption of the backlight, which accounts for most of the power consumption of the liquid crystal display device, can be reduced.

Note that an LED may be used as the light source of the scanning backlight. The scanning backlight in that case is as shown in FIG. 66(B). The scanning backlight shown in FIG. 66B includes a diffusion plate 6611 and light sources 6612-1 to 6612-N in which LEDs are arranged side by side. When LEDs are used as the light source of the scanning backlight, there is an advantage that the backlight can be thin and light. There is also the advantage that the color reproduction range can be widened. Furthermore, L
Since the LEDs arranged side by side with the light sources 6612-1 to 6612-N with the EDs arranged side by side can also be scanned in the same manner, a point scanning type backlight can also be used. If it is of the point scanning type, the image quality of moving images can be further improved.

Even when LEDs are used as the light source of the backlight, they can be driven by changing the luminance as shown in FIG. 66(C).

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each drawing of this embodiment may be applied, combined, replaced, etc. with respect to the content (may be part of) described in the drawing of another embodiment. can be done freely. Furthermore, in the drawings of this embodiment, more drawings can be configured by combining each part with another embodiment.

In addition, the present embodiment is an example of a case where the content (or part of it) described in another embodiment is embodied, an example of a slightly modified case, an example of a partially changed case, and an improved case. An example of the case,
An example of detailed description, an example of application, and an example of related parts are shown. Therefore, the contents described in other embodiments can be freely applied, combined, or replaced with this embodiment.

(Embodiment 10)
In this embodiment mode, the operation of the display device will be described.

FIG. 67 is a diagram illustrating a configuration example of a display device.

The display device includes a pixel portion 6701 , a signal line driver circuit 6703 and a scan line driver circuit 6704 . In the pixel portion 6701, a plurality of signal lines S1 to Sm are arranged extending from the signal line driver circuit 6703 in the column direction. In the pixel portion 6701, a plurality of scanning lines G1 to Gn are arranged extending from the scanning line driver circuit 6704 in the row direction. Pixels 6702 are arranged in a matrix at the intersections of the plurality of signal lines S1 to Sm and the plurality of scanning lines G1 to Gn.

Note that the signal line driver circuit 6703 has a function of outputting a signal to each of the signal lines S1 to Sn. This signal may be called a video signal. Note that the scan line driver circuit 6704 has a function of outputting a signal to each of the scan lines G1 to Gm. This signal may be called a scanning signal.

Note that the pixel 6702 has at least a switching element connected to the signal line.
This switching element is controlled to be on or off by the potential of the scanning line (scanning signal). The pixel 6702 is selected when the switching element is on, and the pixel 6702 is not selected when the switching element is off.

When the pixel 6702 is selected (selected state), a video signal is input to the pixel 6702 from the signal line. The state of the pixel 6702 (for example, luminance, transmittance, voltage of the storage capacitor, etc.) changes according to the input video signal.

When the pixel 6702 is not selected (unselected state), no video signal is input to the pixel 6702 . However, since the pixel 6702 holds a potential according to the video signal input at the time of selection, the pixel 6702 maintains (for example, luminance, transmittance, voltage of the storage capacitor, etc.) according to the video signal.

Note that the configuration of the display device is not limited to that shown in FIG. For example, new wirings (scanning lines, signal lines, power supply lines, capacitor lines, common lines, or the like) may be added depending on the structure of the pixel 6702 .
As another example, circuits with various functions may be added.

FIG. 68 shows an example of a timing chart for explaining the operation of the display device.

The timing chart in FIG. 68 shows one frame period corresponding to the period for displaying an image for one screen. One frame period is not particularly limited, but the person who sees the image flickers (flicker)
is preferably at least 1/60 second or less so as not to feel

The timing chart of FIG. 68 shows the scanning line G1 of the first row, the scanning line Gi of the i-th row (scanning line G1
to Gm), the i+1-th scanning line Gi+1, and the m-th scanning line Gm.

Note that the pixels 6702 connected to the scanning line are also selected at the same time when the scanning line is selected. For example, when the i-th scanning line Gi is selected, the pixel 6702 connected to the i-th scanning line Gi is also selected.

Each of the scanning lines G1 to Gm is selected in order from the first scanning line G1 to the m-th scanning line Gm (hereinafter also referred to as scanning). For example, during the period when the i-th scanning line Gi is selected, the scanning lines other than the i-th scanning line Gi (G1 to Gi−1, Gi+1 to Gm
) is not selected. Then, in the next period, the i+1-th scanning line Gi+1 is selected. Note that a period in which one scanning line is selected is called one gate selection period.

Therefore, when a row of scan lines is selected, the pixels 670 connected to that scan line are
2, video signals are input from the signal lines G1 to Gm, respectively. For example, while the i-th scanning line Gi is selected, the plurality of pixels 67 connected to the i-th scanning line Gi
02 inputs arbitrary video signals from the respective signal lines S1 to Sn. Thus, individual pixels 6702 can be independently controlled by scanning and video signals.

Next, a case where one gate selection period is divided into a plurality of sub-gate selection periods will be described.
FIG. 69 shows a timing chart when one gate selection period is divided into two sub-gate selection periods (first sub-gate selection period and second sub-gate selection period).

Note that one gate selection period can be divided into three or more sub-gate selection periods.

The timing chart in FIG. 69 shows one frame period corresponding to the period for displaying an image for one screen. One frame period is not particularly limited, but the person who sees the image flickers (flicker)
is preferably at least 1/60 second or less so as not to feel

Note that one frame consists of two subframes (first subframe and second subframe)
is divided into

In the timing chart of FIG. 69, the i-th scanning line Gi, the i+1-th scanning line Gi+1, j
It shows the timing at which the row scanning line Gj (any one of the scanning lines Gi+1 to Gm), the j+1 row scanning line, and the Gj+1 row scanning line Gj+1 are selected.

Note that the pixels 6702 connected to the scanning line are also selected at the same time when the scanning line is selected. For example, when the i-th scanning line Gi is selected, the pixel 6702 connected to the i-th scanning line Gi is also selected.

Each of the scanning lines G1 to Gm is sequentially scanned within each sub-gate selection period. For example, in one gate selection period, the i-th scanning line Gi is selected during the first sub-gate selection period, and the j-th scanning line Gj is selected during the second sub-gate selection period.
Then, in one gate selection period, it is possible to operate as if scanning signals for two rows were selected at the same time. At this time, different video signals are input to the signal lines S1 to Sn during the first sub-gate selection period and the second sub-gate selection period. therefore,
A plurality of pixels 6702 connected to the i-th row and a plurality of pixels 670 connected to the j-th row
2 can receive separate video signals.

Next, a drive method for converting the frame rate of input image data (also referred to as input frame rate) and the frame rate of display (also referred to as display frame rate) will be described. Note that the frame rate is the number of frames per second, and the unit is Hz.

In this embodiment, the input frame rate does not necessarily have to match the display frame rate. When the input frame rate and the display frame rate are different, the frame rate can be converted by a circuit (frame rate conversion circuit) for converting the frame rate of image data. By doing so, even when the input frame rate and the display frame rate are different, display can be performed at various display frame rates.

When the input frame rate is higher than the display frame rate, part of the input image data can be discarded to convert to various display frame rates for display.
In this case, since the display frame rate can be reduced, the operating frequency of the driving circuit for display can be reduced, and power consumption can be reduced. On the other hand, when the input frame rate is lower than the display frame rate, all or part of the input image data is displayed multiple times, another image is generated from the input image data, and the input image data is By using means such as generating irrelevant images, it is possible to convert and display at various display frame rates. In this case, the quality of moving images can be improved by increasing the display frame rate.

In this embodiment, a frame rate conversion method when the input frame rate is lower than the display frame rate will be described in detail. Note that the frame rate conversion method when the input frame rate is higher than the display frame rate can be realized by performing the reverse procedure of the frame rate conversion method when the input frame rate is lower than the display frame rate. can.

In this embodiment, an image displayed at the same frame rate as the input frame rate is called a basic image. On the other hand, an image that is displayed at a frame rate different from that of the base image and that is displayed to match the input frame rate and the display frame rate is called an interpolated image. The same image as the input image data can be used as the basic image. The same image as the basic image can be used for the interpolated image. Furthermore, an image different from the basic image can be created, and the created image can be used as the interpolated image.

When creating an interpolated image, the temporal change (movement of the image) in the input image data is detected, and an intermediate state image is used as the interpolated image. as an interpolated image, a method in which a plurality of different images are created from the input image data, and the plurality of images are presented continuously in time (one of the plurality of images is used as a basic image,
The remainder is used as an interpolated image) so that the observer perceives as if an image corresponding to the input image data was displayed. Methods of creating a plurality of different images from input image data include a method of converting the gamma value of the input image data, a method of dividing the gradation values included in the input image data, and the like.

An image in an intermediate state (intermediate image) is an image obtained by detecting a temporal change (movement of an image) in input image data and interpolating the detected movement. Obtaining an intermediate image by such a method is called motion compensation.

Next, a specific example of the frame rate conversion method will be described. According to this method, any rational number (n/m) times frame rate conversion can be realized. Here, n and m are integers of 1 or more. The frame rate conversion method in this embodiment can be divided into a first step and a second step. Here, the first step is to convert the frame rate to an arbitrary rational number (n/m) times. Here, a basic image may be used as the interpolated image, or an intermediate image obtained by motion compensation may be used as the interpolated image. The second step is to create a plurality of different images (sub-images) from the input image data or each image subjected to the frame rate conversion in the first step, and temporally contiguous the plurality of sub-images. It is a step for performing a method of displaying by By using the method according to the second step, it is possible to visually perceive to the human eye that the original image is displayed even though a plurality of different images are actually displayed.

Note that the frame rate conversion method according to the present embodiment may use both the first step and the second step, may omit the first step and use only the second step, or may use only the second step. Step 2 may be omitted and only the first step may be used.

First, as the first step, arbitrary rational number (n/m) times frame rate conversion will be described. (See FIG. 70) In FIG. 70, the horizontal axis is time, and the vertical axis is divided into cases for various n and m. Figures in FIG. 70 represent schematic diagrams of images to be displayed, and display timings are represented by their horizontal positions. Furthermore, it is assumed that the motion of the image is schematically represented by the points displayed in the figure. However, this is an example for explanation, and the displayed image is not limited to this. This method can be applied to various images.

A period Tin represents the cycle of the input image data. The cycle of input image data corresponds to the input frame rate. For example, when the input frame rate is 60 Hz, the period of input image data is 1/60 second. Similarly, if the input frame rate is 50Hz,
The period of the input image data is 1/50 second. Thus, the period of the input image data (unit:
seconds) is the reciprocal of the input frame rate (unit: Hz). Various input frame rates can be used. For example, 24Hz, 50Hz, 60Hz, 70Hz,
48 Hz, 100 Hz, 120 Hz, 140 Hz, etc. can be mentioned. where 2
4 Hz is a frame rate used for film movies and the like. 50 Hz is a frame rate used for PAL standard video signals and the like. 60 Hz is a frame rate used for NTSC standard video signals and the like. 70 Hz is a frame rate used for display input signals of personal computers and the like. 48Hz, 100Hz, 120Hz,
140 Hz, is a frame rate double these. Note that the frame rate is not limited to double, and various multiples of the frame rate may be used. Thus, according to the method shown in this embodiment, it is possible to realize frame rate conversion for input signals of various standards.

The procedure for arbitrary rational (n/m) times frame rate conversion in the first step is as follows.
As procedure 1, the k-th interpolated image (k is an integer of 1 or more; the initial value is 1
) is displayed. It is assumed that the display timing of the k-th interpolated image is the point in time when a period obtained by multiplying the cycle of the input image data by k (m/n) has passed since the first basic image was displayed.
As procedure 2, it is determined whether the coefficient k(m/n) used for determining the display timing of the k-th interpolated image is an integer. If it is an integer, the (k(m/n)+1)-th basic image is displayed at the display timing of the k-th interpolated image, and the first step ends. If it is not an integer, go to step 3.
As procedure 3, an image to be used as the k-th interpolation image is determined. Specifically, the coefficient k(m/n) used for determining the display timing of the k-th interpolated image is converted into x+y/n. Here x and y are integers and y is a number less than n. When the k-th interpolated image is an intermediate image obtained by motion compensation, the k-th interpolated image is the (x+1)-th interpolated image.
) to the (x+2)-th basic image multiplied by (y/n). If the k-th interpolated image is the same image as the basic image, the (x+1)-th basic image can be used. A method of obtaining an intermediate image as an image corresponding to a motion obtained by multiplying the motion of the image by (y/n) will be described in detail in another section.
As procedure 4, the target interpolated image is moved to the next interpolated image. Specifically, the value of k is incremented by 1, and the process returns to step 1.

Next, in the procedure in the first step, the values of n and m will be specifically shown and explained in detail.

Note that the mechanism for executing the procedure in the first step may be implemented in the device, or may be determined in advance at the design stage of the device. If the apparatus is equipped with a mechanism for executing the procedure in the first step, it becomes possible to switch the driving method so that the optimum operation according to the situation is performed. The conditions here refer to the content of the image data, the environment inside and outside the device (temperature, humidity, air pressure, light, sound, magnetic field, electric field, radiation dose,
altitude, acceleration, movement speed, etc.), user settings, software version, etc. On the other hand, if the mechanism for executing the procedure in the first step is determined in advance at the design stage of the device, the optimum driving circuit can be used for each driving method, and the mechanism is already determined. As a result, a reduction in manufacturing costs can be expected due to the effect of mass production.

When n=1, m=1, that is, when the conversion ratio (n/m) is 1 (n=1, m=1 in FIG. 70), the operation in the first step is as follows. First, when k=1, in procedure 1, the display timing of the first interpolated image for the first basic image is determined. The display timing of the first interpolated image is set so that the cycle of the input image data is k (m
/n) times, i.e., when a period of time multiplied by 1 has elapsed.

Next, in procedure 2, it is determined whether or not the coefficient k(m/n) used for determining the display timing of the first interpolated image is an integer. Here, since the coefficient k(m/n) is 1, it is an integer. Therefore, at the display timing of the first interpolated image, the (k(m/n)+1)-th, that is, the second basic image is displayed, and the first step ends.

That is, when the conversion ratio is 1, the k-th image is the basic image, the k+1-th image is the basic image, and the image display cycle is one time the cycle of the input image data. do.

As a concrete expression, when the conversion ratio is 1 (n/m=1),
i-th (i is a positive integer) image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
A display device driving method for sequentially displaying a k+1-th image and an interval equal to the cycle of input image data,
the k-th image is displayed according to the i-th image data;
The k+1-th image is displayed according to the i+1-th image data.

Here, when the conversion ratio is 1, the frame rate conversion circuit can be omitted, so there is an advantage that the manufacturing cost can be reduced. Furthermore, a conversion ratio of 1 has the advantage that the quality of moving images can be improved over a conversion ratio of less than 1. Furthermore, when the conversion ratio is 1, there is an advantage that power consumption and manufacturing cost can be reduced as compared with the case where the conversion ratio is greater than 1.

When n=2 and m=1, that is, when the conversion ratio (n/m) is 2 (where n=2 and m=1 in FIG. 70), the operation in the first step is as follows. First, when k=1, in procedure 1, the display timing of the first interpolated image for the first basic image is determined. The display timing of the first interpolated image is set so that the cycle of the input image data is k (m
/n) times, i.e., when a period of 1/2 times has elapsed.

Next, in procedure 2, it is determined whether or not the coefficient k(m/n) used for determining the display timing of the first interpolated image is an integer. Here, the coefficient k(m/n) is 1/2, so it is not an integer. Therefore, proceed to step 3.

In procedure 3, an image to be used as the first interpolated image is determined. Therefore, the factor 1/2 is x
+ Convert to the form y/n. For a factor of 1/2, x=0 and y=1. When the first interpolated image is an intermediate image obtained by motion compensation, the first interpolated image is the (x+
1) An intermediate image obtained as an image corresponding to a motion obtained by multiplying the motion of the image from the first basic image to the (x+2)th, i.e. the second basic image, by y/n, that is, by 1/2. first
If the interpolated image is the same image as the basic image, the (x+1)th, ie, the first basic image can be used.

By the procedure so far, the display timing of the first interpolated image and the image to be displayed as the first interpolated image can be determined. Next, in procedure 4, the target interpolated image is moved from the first interpolated image to the second interpolated image. That is, change k from 1 to 2 and return to procedure 1.

When k=2, in procedure 1, the display timing of the second interpolated image with respect to the first basic image is determined. The display timing of the second interpolated image is the point in time when a period obtained by multiplying the cycle of the input image data by k (m/n), ie, by 1, has elapsed since the first basic image was displayed.

Next, in procedure 2, it is determined whether or not the coefficient k(m/n) used for determining the display timing of the second interpolated image is an integer. Here, since the coefficient k(m/n) is 1, it is an integer. Therefore, at the display timing of the second interpolated image, the (k(m/n)+1)-th, that is, the second basic image is displayed, and the first step ends.

That is, if the conversion ratio is 2 (n/m=2),
The kth image is the base image,
The k+1th image is an interpolated image,
The k+2-th image is a basic image, and the image display cycle is 1/2 times the cycle of the input image data.

As a concrete expression, when the conversion ratio is 2 (n/m=2),
i-th (i is a positive integer) image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
A display device driving method for sequentially displaying a k+2-th image and an image at an interval of 1/2 times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 1/2;
The k+2-th image is displayed according to the i+1-th image data.

As another concrete expression, if the conversion ratio is 2 (n/m=2),
i-th (i is a positive integer) image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
A display device driving method for sequentially displaying a k+2-th image and an image at an interval of 1/2 times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to the i-th image data;
The k+2-th image is displayed according to the i+1-th image data.

Specifically, when the conversion ratio is 2, it is also called double-speed driving or simply double-speed driving.
For example, if the input frame rate is 60 Hz, the display frame rate is 120 Hz (
120 Hz drive). Then, one input image is displayed twice in succession. At this time, if the interpolated image is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so that the quality of the moving image can be significantly improved. Furthermore, when the display device is an active matrix liquid crystal display device,
A particularly remarkable image quality improvement effect is brought about. This is related to the problem of insufficient write voltage due to so-called dynamic capacitance, in which the electrostatic capacitance of the liquid crystal element varies with applied voltage. That is, by making the display frame rate higher than the input frame rate, the frequency of the image data write operation can be increased, thereby reducing obstacles such as moving image tailing and afterimages caused by insufficient write voltage due to dynamic capacitance. be able to. Furthermore, it is also effective to combine AC driving and 120 Hz driving of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 120 Hz, the frequency of the AC drive is set to an integral multiple or a fraction of that (for example, 30 Hz, 60 Hz, 120 Hz, 240 Hz, etc.). It can be reduced to the extent that it is imperceptible to the human eye.

When n=3 and m=1, that is, when the conversion ratio (n/m) is 3 (where n=3 and m=1 in FIG. 70), the operation in the first step is as follows. First, when k=1, in procedure 1, the display timing of the first interpolated image for the first basic image is determined. The display timing of the first interpolated image is set so that the cycle of the input image data is k (m
/n) times, that is, when a period of 1/3 times has elapsed.

Next, in procedure 2, it is determined whether or not the coefficient k(m/n) used for determining the display timing of the first interpolated image is an integer. Here, the coefficient k(m/n) is 1/3, so it is not an integer. Therefore, proceed to step 3.

In procedure 3, an image to be used as the first interpolated image is determined. Therefore, the factor 1/3 is x
+ Convert to the form y/n. For a factor of 1/3, x=0 and y=1. When the first interpolated image is an intermediate image obtained by motion compensation, the first interpolated image is the (x+
1) An intermediate image obtained as an image corresponding to a motion obtained by multiplying the motion of the image from the first basic image to the (x+2)th, i.e., the second basic image, by y/n, ie, ⅓ times. first
If the interpolated image is the same image as the basic image, the (x+1)th, ie, the first basic image can be used.

By the procedure so far, the display timing of the first interpolated image and the image to be displayed as the first interpolated image can be determined. Next, in procedure 4, the target interpolated image is moved from the first interpolated image to the second interpolated image. That is, change k from 1 to 2 and return to procedure 1.

When k=2, in procedure 1, the display timing of the second interpolated image with respect to the first basic image is determined. The display timing of the second interpolated image is the point in time when a period obtained by multiplying the period of the input image data by k (m/n) times, ie, by 2/3, has elapsed since the first basic image was displayed.

Next, in procedure 2, it is determined whether or not the coefficient k(m/n) used for determining the display timing of the second interpolated image is an integer. Here, the coefficient k(m/n) is 2/3, so it is not an integer. Therefore, proceed to step 3.

In procedure 3, an image to be used as the second interpolated image is determined. Therefore, the factor 2/3 is x
+ Convert to the form y/n. For a factor of 2/3, x=0 and y=2. When the second interpolated image is an intermediate image obtained by motion compensation, the second interpolated image is the (x+
1) An intermediate image obtained as an image corresponding to a motion obtained by multiplying the motion of the image from the first basic image to the (x+2)th, i.e., the second basic image, by y/n, ie, 2/3 times. second
If the interpolated image is the same image as the basic image, the (x+1)th, ie, the first basic image can be used.

By the procedure so far, the display timing of the second interpolated image and the image to be displayed as the second interpolated image can be determined. Next, in procedure 4, the target interpolated image is moved from the second interpolated image to the third interpolated image. That is, change k from 2 to 3 and return to procedure 1.

When k=3, in procedure 1, the display timing of the third interpolated image with respect to the first basic image is determined. The display timing of the third interpolated image is the point in time when a period obtained by multiplying the cycle of the input image data by k (m/n), ie, by 1, has elapsed since the first basic image was displayed.

Next, in procedure 2, it is determined whether or not the coefficient k(m/n) used for determining the display timing of the third interpolated image is an integer. Here, since the coefficient k(m/n) is 1, it is an integer. Therefore, at the display timing of the third interpolated image, the (k(m/n)+1)-th, that is, the second basic image is displayed, and the first step ends.

That is, if the conversion ratio is 3 (n/m=3),
The kth image is the base image,
The k+1th image is an interpolated image,
The k+2th image is an interpolated image,
The k+3th image is a basic image, and the image display cycle is ⅓ times the cycle of the input image data.

As a concrete expression, when the conversion ratio is 3 (n/m=3),
i-th (i is a positive integer) image data;
is sequentially input as input image data at a constant cycle, and
a k-th image (k is a positive integer);
a k+1-th image;
a k+2th image;
A display device driving method for sequentially displaying a k+3-th image and an image at intervals of ⅓ times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by ⅓;
the k+2-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image to the i+1-th image by 2/3;
The k+3th image is characterized by being displayed according to the i+1th image data.

As another specific expression, if the conversion ratio is 3 (n/m=3),
i-th (i is a positive integer) image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
a k+2th image;
A display device driving method for sequentially displaying a k+3-th image and an image at intervals of ⅓ times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to the i-th image data;
the k+2 th image is displayed according to the i th image data;
The k+3th image is characterized by being displayed according to the i+1th image data.

Here, when the conversion ratio is 3, there is an advantage that the quality of moving images can be improved more than when the conversion ratio is smaller than 3. Furthermore, when the conversion ratio is 3, there is an advantage that power consumption and manufacturing cost can be reduced more than when the conversion ratio is greater than 3.

Specifically, when the conversion ratio is 3, it is also called triple-speed driving. For example, if the input frame rate is 60 Hz, the display frame rate is 180 Hz (180 Hz drive). Then, one input image is displayed three times in succession. At this time, if the interpolated image is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so that the quality of the moving image can be significantly improved. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of shortage of write voltage due to dynamic capacitance can be avoided, so that a remarkable image quality improvement effect can be brought about against troubles such as trailing of moving images and afterimages. Furthermore, the AC drive of the liquid crystal display and the 180 Hz
It is also effective to combine driving. That is, the driving frequency of the liquid crystal display device is set to 180H.
z, and the frequency of the AC drive is set to an integer multiple or an integral fraction thereof (for example, 45 Hz, 9
0 Hz, 180 Hz, 360 Hz, etc.), it is possible to reduce flicker that appears due to AC drive to a level that is not perceived by the human eye.

n=3, m=2, that is, the conversion ratio (n/m) is 3/2 (n=3, m=2 in FIG. 70)
, the operation in the first step is as follows. First, when k=1, procedure 1
Now, the display timing of the first interpolated image with respect to the first basic image is determined. The display timing of the first interpolated image is set so that the cycle of the input image data is k after the first basic image is displayed.
(m/n) times, that is, when a period of time multiplied by 2/3 has elapsed.

Next, in procedure 2, it is determined whether or not the coefficient k(m/n) used for determining the display timing of the first interpolated image is an integer. Here, the coefficient k(m/n) is 2/3, so it is not an integer. Therefore, proceed to step 3.

In procedure 3, an image to be used as the first interpolated image is determined. Therefore, the factor 2/3 is x
+ Convert to the form y/n. For a factor of 2/3, x=0 and y=2. When the first interpolated image is an intermediate image obtained by motion compensation, the first interpolated image is the (x+
1) An intermediate image obtained as an image corresponding to a motion obtained by multiplying the motion of the image from the first basic image to the (x+2)th, i.e., the second basic image, by y/n, ie, 2/3 times. first
If the interpolated image is the same image as the basic image, the (x+1)th, ie, the first basic image can be used.

By the procedure so far, the display timing of the first interpolated image and the image to be displayed as the first interpolated image can be determined. Next, in procedure 4, the target interpolated image is moved from the first interpolated image to the second interpolated image. That is, change k from 1 to 2 and return to procedure 1.

When k=2, in procedure 1, the display timing of the second interpolated image with respect to the first basic image is determined. The display timing of the second interpolated image is the point in time when a period obtained by multiplying the cycle of the input image data by k (m/n), that is, by 4/3, has elapsed since the first basic image was displayed.

Next, in procedure 2, it is determined whether or not the coefficient k(m/n) used for determining the display timing of the second interpolated image is an integer. Here, the coefficient k(m/n) is 4/3, so it is not an integer. Therefore, proceed to step 3.

In procedure 3, an image to be used as the second interpolated image is determined. Therefore, the factor 4/3 is x
+ Convert to the form y/n. For a factor of 4/3, x=1 and y=1. When the second interpolated image is an intermediate image obtained by motion compensation, the second interpolated image is the (x+
1) An intermediate image obtained as an image corresponding to a motion obtained by multiplying the motion of the image from the second basic image to the (x+2)th, i.e., the third basic image, by y/n, ie, ⅓ times. second
If the interpolated image is the same image as the basic image, the (x+1)th, ie, the second basic image can be used.

By the procedure so far, the display timing of the second interpolation image and the image to be displayed as the second interpolation image can be determined. Next, in procedure 4, the target interpolated image is moved from the second interpolated image to the third interpolated image. That is, change k from 2 to 3 and return to procedure 1.

When k=3, in procedure 1, the display timing of the third interpolated image with respect to the first basic image is determined. The display timing of the third interpolated image is the point in time when a period obtained by multiplying the period of the input image data by k (m/n), that is, by doubling the period of the input image data has elapsed since the first basic image was displayed.

Next, in procedure 2, it is determined whether or not the coefficient k(m/n) used for determining the display timing of the third interpolated image is an integer. Here, since the coefficient k(m/n) is 2, it is an integer. Therefore, at the display timing of the third interpolated image, the (k(m/n)+1)-th, that is, the third basic image is displayed, and the first step ends.

That is, if the conversion ratio is 3/2 (n/m=3/2),
The kth image is the base image,
The k+1th image is an interpolated image,
The k+2th image is an interpolated image,
The k+3th image is a basic image, and the image display cycle is ⅔ times the cycle of the input image data.

As a concrete expression, when the conversion ratio is 3/2 (n/m=3/2),
i-th (i is a positive integer) image data;
i+1-th image data;
is sequentially input as input image data at a constant cycle, and
a k-th image (k is a positive integer);
a k+1-th image;
a k+2th image;
A display device driving method for sequentially displaying a k+3-th image and an image at an interval of 2/3 times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 2/3;
The k+2 th image is ⅓ the motion from the i+1 th image to the i+2 th image.
displayed according to the image data corresponding to the multiplied movement,
The k+3-th image is displayed according to the i+2-th image data.

As another concrete expression, if the conversion ratio is 3/2 (n/m=3/2),
i-th (i is a positive integer) image data;
i+1-th image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
a k+2th image;
A display device driving method for sequentially displaying a k+3-th image and an image at an interval of 2/3 times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to the i-th image data;
the k+2-th image is displayed according to the i+1-th image data;
The k+3-th image is displayed according to the i+2-th image data.

Here, when the conversion ratio is 3/2, there is an advantage that the quality of moving images can be improved more than when the conversion ratio is smaller than 3/2. Further, if the conversion ratio is 3/2, then the conversion ratio is 3/
It has the advantage of being able to reduce power consumption and manufacturing costs compared to the case of greater than two.

Specifically, when the conversion ratio is 3/2, it is also called 3/2 speed driving or 1.5 speed driving. For example, if the input frame rate is 60 Hz, the display frame rate is 90
Hz (90 Hz drive). Then, the images are displayed three times in succession for the two input images. At this time, if the interpolated image is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so that the quality of the moving image can be significantly improved. In particular, compared to driving methods with high driving frequencies such as 120 Hz driving (double speed driving) and 180 Hz driving (triple speed driving), motion compensation can reduce the operating frequency of the circuit that obtains the intermediate image, so that an inexpensive circuit can be used. , manufacturing costs and power consumption can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided.
This provides a particularly remarkable image quality improvement effect for obstacles such as afterimages. Furthermore, it is also effective to combine AC driving and 90 Hz driving of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 90 Hz, the frequency of the AC drive is set to an integer multiple or an integer fraction (for example, 3
0 Hz, 45 Hz, 90 Hz, 180 Hz, etc.), it is possible to reduce flicker that appears due to AC drive to a level that is not perceived by the human eye.

Details of the procedure for positive integers n and m other than the above are omitted, but the conversion ratio can be set as an arbitrary rational number (n/m) by following the procedure for frame rate conversion in the first step. can. Among the combinations of positive integers n and m, the conversion ratio (n/
Combinations in which m) can be canceled can be handled in the same manner as conversion ratios after cancellation.

For example, when n=4, m=1, that is, the conversion ratio (n/m) is 4 (n=4, m=1 in FIG. 70),
The kth image is the base image,
The k+1th image is an interpolated image,
The k+2th image is an interpolated image,
The k+3th image is an interpolated image,
The k+4th image is a basic image, and the image display cycle is 1/4 times the cycle of the input image data.

More specifically, when the conversion ratio is 4 (n/m=4),
i-th (i is a positive integer) image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
a k+2th image;
a k+3th image;
A display device driving method for sequentially displaying a k+4-th image and an image at an interval of 1/4 times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to image data corresponding to a movement obtained by multiplying the movement from the i-th image data to the i+1-th image data by 1/4;
the k+2-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 1/2;
the k+3-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 3/4;
The k+4-th image is displayed according to the i+1-th image data.

As another concrete expression, if the conversion ratio is 4 (n/m=4),
i-th (i is a positive integer) image data;
is sequentially input as input image data at a constant cycle, and
a k-th image (k is a positive integer);
a k+1-th image;
a k+2th image;
a k+3th image;
A display device driving method for sequentially displaying a k+4-th image and an image at an interval of 1/4 times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to the i-th image data;
the k+2 th image is displayed according to the i th image data;
the k+3 th image is displayed according to the i th image data;
The k+4-th image is displayed according to the i+1-th image data.

Here, when the conversion ratio is 4, there is an advantage that the quality of moving images can be improved more than when the conversion ratio is smaller than 4. Furthermore, when the conversion ratio is 4, there is an advantage that the power consumption and manufacturing cost can be reduced compared to when the conversion ratio is greater than 4.

Specifically, when the conversion ratio is 4, it is also called quadruple speed driving. For example, if the input frame rate is 60 Hz, the display frame rate is 240 Hz (240 Hz drive). Then, one input image is displayed four times in succession. At this time, if the interpolated image is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so that the quality of the moving image can be significantly improved. In particular, 120
Compared to drive methods with low drive frequencies such as Hz drive (double speed drive) and 180 Hz drive (triple speed drive), intermediate images obtained by motion compensation with higher accuracy can be used as interpolated images. Motion can be smoothed out, and the quality of moving images can be significantly improved. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, it is effective to combine the AC drive and the 240 Hz drive of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 240 Hz, by setting the frequency of the AC drive to an integral multiple or a fraction of that (for example, 30 Hz, 40 Hz, 60 Hz, 120 Hz, etc.), the flicker caused by the AC drive is It can be reduced to the extent that it is imperceptible to the human eye.

Furthermore, for example, n=4, m=3, that is, the conversion ratio (n/m) is 4/3 (n=
4, where m = 3),
The kth image is the base image,
The k+1th image is an interpolated image,
The k+2th image is an interpolated image,
The k+3th image is an interpolated image,
The k+4th image is a basic image, and the image display cycle is 3/4 times the cycle of the input image data.

More specifically, when the conversion ratio is 4/3 (n/m=4/3),
i-th (i is a positive integer) image data;
i+1-th image data;
i+2th image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
a k+2th image;
a k+3th image;
A display device driving method for sequentially displaying a k+4-th image and an image at intervals of 3/4 times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 3/4;
The k+2-th image has half the motion from the i+1-th image to the i+2-th image.
displayed according to the image data corresponding to the multiplied movement,
The k+3 th image is ¼ the motion from the i+2 th image to the i+3 th image.
displayed according to the image data corresponding to the multiplied movement,
The k+4th image is characterized by being displayed according to the i+3th image data.

As another concrete expression, if the conversion ratio is 4/3 (n/m=4/3),
i-th (i is a positive integer) image data;
i+1-th image data;
i+2th image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
a k+2th image;
a k+3th image;
A display device driving method for sequentially displaying a k+4-th image and an image at intervals of 3/4 times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to the i-th image data;
the k+2-th image is displayed according to the i+1-th image data;
the k+3th image is displayed according to the i+2th image data;
The k+4th image is characterized by being displayed according to the i+3th image data.

Here, when the conversion ratio is 4/3, there is an advantage that the quality of moving images can be improved more than when the conversion ratio is smaller than 4/3. Furthermore, if the conversion ratio is 4/3, then the conversion ratio is 4/
It has the advantage of being able to reduce power consumption and manufacturing costs compared to the case of greater than 3.

Specifically, when the conversion ratio is 4/3, it is also called 4/3 speed driving or 1.25 speed driving. For example, if the input frame rate is 60 Hz, the display frame rate is 8
0 Hz (80 Hz drive). Then, the images are displayed four times in succession with respect to the three input images. At this time, if the interpolated image is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so that the quality of the moving image can be significantly improved. In particular, compared to driving methods with high driving frequencies such as 120 Hz driving (double speed driving) and 180 Hz driving (triple speed driving), motion compensation can reduce the operating frequency of the circuit that obtains the intermediate image, so that an inexpensive circuit can be used. , manufacturing costs and power consumption can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, it is also effective to combine AC driving and 80 Hz driving of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 80 Hz, the frequency of the AC drive is set to an integer multiple or an integer fraction thereof (for example,
40 Hz, 80 Hz, 160 Hz, 240 Hz, etc.), it is possible to reduce flicker that appears due to AC drive to a level that is not perceived by the human eye.

Furthermore, for example, n=5, m=1, that is, the conversion ratio (n/m) is 5 (n=5, m in FIG.
m = 1),
The kth image is the base image,
The k+1th image is an interpolated image,
The k+2th image is an interpolated image,
The k+3th image is an interpolated image,
The k+4th image is an interpolated image,
The k+5th image is a basic image, and the image display cycle is 1/5 times the cycle of the input image data.

More specifically, when the conversion ratio is 5 (n/m=5),
i-th (i is a positive integer) image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
a k+2th image;
a k+3th image;
the k+4th image;
A method of driving a display device for sequentially displaying a k+5th image and an image at intervals of ⅕ times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by ⅕;
the k+2-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 2/5;
the k+3-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 3/5;
the k+4-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 4/5;
The k+5-th image is displayed according to the i+1-th image data.

As another specific expression, if the conversion ratio is 5 (n/m=5),
i-th (i is a positive integer) image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
a k+2th image;
a k+3th image;
the k+4th image; and
A driving method for a display device for sequentially displaying a k+5th image and an image at intervals of ⅕ times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to the i-th image data;
the k+2 th image is displayed according to the i th image data;
the k+3 th image is displayed according to the i th image data;
the k+4th image is displayed according to the i-th image data;
The k+5-th image is displayed according to the i+1-th image data.

Here, when the conversion ratio is 5, there is an advantage that the quality of moving images can be improved more than when the conversion ratio is smaller than 5. Furthermore, when the conversion ratio is 5, there is an advantage that the power consumption and the manufacturing cost can be reduced compared to when the conversion ratio is greater than 5.

Specifically, when the conversion ratio is 5, it is also called quintuple speed driving. For example, if the input frame rate is 60 Hz, the display frame rate is 300 Hz (300 Hz drive). Then, one input image is displayed five times in succession. At this time, if the interpolated image is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so that the quality of the moving image can be significantly improved. In particular, 120
Compared to drive methods with low drive frequencies such as Hz drive (double speed drive) and 180 Hz drive (triple speed drive), intermediate images obtained by motion compensation with higher accuracy can be used as interpolated images. The motion can be smoothed and the quality of moving images can be significantly improved. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, it is also effective to combine AC driving and 300 Hz driving of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 300 Hz, the frequency of the AC drive is set to an integer multiple or a fraction of that (for example, 30 Hz, 50 Hz, 60 Hz, 100 Hz, etc.). It can be reduced to the extent that it is imperceptible to the human eye.

Further, for example, n=5, m=2, that is, the conversion ratio (n/m) is 5/2 (n=
5, where m = 2),
The kth image is the base image,
The k+1th image is an interpolated image,
The k+2th image is an interpolated image,
The k+3th image is an interpolated image,
The k+4th image is an interpolated image,
The k+5th image is a basic image, and the image display cycle is 1/5 times the cycle of the input image data.

More specifically, when the conversion ratio is 5/2 (n/m=5/2),
i-th (i is a positive integer) image data;
i+1-th image data;
is sequentially input as input image data at a constant cycle, and
a k-th (k is a positive integer) image;
a k+1-th image;
a k+2th image;
a k+3th image;
the k+4th image;
A driving method for a display device for sequentially displaying a k+5th image and an image at intervals of ⅕ times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 2/5;
the k+2-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 4/5;
the k+3-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i+1-th image data to the i+2-th image data by ⅕;
the k+4-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i+1-th image data to the i+2-th image data by 3/5;
The k+5th image is characterized by being displayed according to the i+2th image data.

As another concrete expression, if the conversion ratio is 5/2 (n/m=5/2),
i-th (i is a positive integer) image data;
i+1-th image data;
is sequentially input as input image data at a constant cycle, and
a k-th image (k is a positive integer);
a k+1-th image;
a k+2th image;
a k+3th image;
the k+4th image; and
A method of driving a display device for sequentially displaying a k+5th image and an image at intervals of ⅕ times the cycle of input image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to the i-th image data;
the k+2 th image is displayed according to the i th image data;
the k+3th image is displayed according to the i+1th image data;
the k+4th image is displayed according to the i+1th image data;
The k+5th image is characterized by being displayed according to the i+2th image data.

Here, when the conversion ratio is 5/2, there is an advantage that the quality of moving images can be improved more than when the conversion ratio is smaller than 5/2. Furthermore, a conversion ratio of 5/2 has the advantage of being able to reduce power consumption and manufacturing costs compared to conversion ratios greater than 5.

Specifically, when the conversion ratio is 5, it is also called 5/2 speed driving or 2.5 speed driving. For example, if the input frame rate is 60Hz, the display frame rate is 150H.
z (150 Hz drive). Then, the images are displayed five times consecutively for the two input images. At this time, if the interpolated image is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so that the quality of the moving image can be significantly improved. In particular, compared to a drive method with a low drive frequency such as 120 Hz drive (double speed drive), intermediate images obtained by motion compensation with higher accuracy can be used as interpolated images, so that the motion of moving images can be smoothed further. can significantly improve the quality of moving images. Furthermore, compared to driving methods with a high driving frequency such as 180 Hz driving (triple speed driving), the motion compensation can reduce the operating frequency of the circuit that obtains the intermediate image. can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of shortage of write voltage due to dynamic capacitance can be avoided, so that a remarkable image quality improvement effect can be brought about against troubles such as trailing of moving images and afterimages. Furthermore, it is also effective to combine AC driving and 150 Hz driving of the liquid crystal display device. That is, the drive frequency of the liquid crystal display device is set to 150 Hz.
while changing the frequency of the AC drive to an integer multiple or an integer fraction (for example, 30 Hz, 50 Hz,
Hz, 75 Hz, 150 Hz, etc.), it is possible to reduce flicker that appears due to AC drive to a level that is not perceived by the human eye.

Thus, by setting positive integers n and m differently, the conversion ratio can be set as any rational number (n/m). Although detailed explanation is omitted, in the range where n is 10 or less,
n=1, m=1, that is, the conversion ratio (n/m)=1 (single-speed drive, 60 Hz),
n=2, m=1, that is, the conversion ratio (n/m)=2 (double speed drive, 120 Hz),
n = 3, m = 1, that is, conversion ratio (n/m) = 3 (triple speed drive, 180 Hz),
n = 3, m = 2, that is, conversion ratio (n/m) = 3/2 (3/2 double speed drive, 90 Hz),
n = 4, m = 1, that is, conversion ratio (n/m) = 4 (4x speed drive, 240 Hz),
n = 4, m = 3, that is, conversion ratio (n/m) = 4/3 (4/3 double speed drive, 80 Hz),
n=5, m=1, that is, the conversion ratio (n/m)=5/1 (5-fold speed drive, 300 Hz),
n = 5, m = 2, that is, conversion ratio (n/m) = 5/2 (5/2 double speed drive, 150 Hz),
n = 5, m = 3, that is, conversion ratio (n/m) = 5/3 (5/3 double speed drive, 100 Hz),
n = 5, m = 4, that is, conversion ratio (n/m) = 5/4 (5/4 double speed drive, 75 Hz),
n = 6, m = 1, that is, conversion ratio (n/m) = 6 (six-speed drive, 360 Hz),
n = 6, m = 5, that is, conversion ratio (n/m) = 6/5 (6/5 double speed drive, 72 Hz),
n=7, m=1, that is, conversion ratio (n/m)=7 (seven times speed drive, 420 Hz),
n = 7, m = 2, that is, conversion ratio (n/m) = 7/2 (7/2 double speed drive, 210 Hz),
n = 7, m = 3, that is, conversion ratio (n/m) = 7/3 (7/3 double speed drive, 140 Hz),
n = 7, m = 4, that is, conversion ratio (n/m) = 7/4 (7/4 double speed drive, 105 Hz),
n = 7, m = 5, that is, conversion ratio (n/m) = 7/5 (7/5 double speed drive, 84 Hz),
n=7, m=6, that is, conversion ratio (n/m)=7/6 (7/6 double speed drive, 70 Hz),
n = 8, m = 1, that is, the conversion ratio (n/m) = 8 (8-fold speed drive, 480 Hz),
n = 8, m = 3, that is, conversion ratio (n/m) = 8/3 (8/3 double speed drive, 160 Hz),
n = 8, m = 5, that is, conversion ratio (n/m) = 8/5 (8/5 double speed drive, 96 Hz),
n=8, m=7, that is, conversion ratio (n/m)=8/7 (8/7 double speed drive, 68.6 Hz)
,
n = 9, m = 1, that is, conversion ratio (n/m) = 9 (9x speed drive, 540 Hz),
n = 9, m = 2, that is, conversion ratio (n/m) = 9/2 (9/2 double speed drive, 270 Hz),
n = 9, m = 4, that is, conversion ratio (n/m) = 9/4 (9/4 double speed drive, 135 Hz),
n = 9, m = 5, that is, conversion ratio (n/m) = 9/5 (9/5 double speed drive, 108 Hz),
n=9, m=7, that is, conversion ratio (n/m)=9/7 (9/7 double speed drive, 77.1 Hz)
,
n=9, m=8, ie conversion ratio (n/m)=9/8 (9/8 double speed drive, 67.5 Hz)
,
n = 10, m = 1, that is, conversion ratio (n/m) = 10 (10x speed drive, 600 Hz),
n=10, m=3, that is, conversion ratio (n/m)=10/3 (10/3 double speed drive, 200H
z),
n=10, m=7, ie conversion ratio (n/m)=10/7 (10/7 double speed drive, 85.7
Hz),
n=10, m=9, that is, the conversion ratio (n/m)=10/9 (10/9 double speed drive, 66.7
Hz),
Combinations of the above are conceivable. Note that the notation of frequency is an example when the input frame rate is 60 Hz, and for other input frame rates, the drive frequency is the value obtained by multiplying the input frame rate by the respective conversion ratio.

Note that when n is an integer greater than 10, specific numbers for n and m are not given, but the procedure for frame rate conversion in the first step can be applied to various n and m. is clear.

It should be noted that the conversion ratio can be determined depending on how much of the image to be displayed includes an image that can be displayed without performing motion compensation in the input image data. Specifically, the smaller m is, the greater the percentage of images that can be displayed without performing motion compensation on the input image data. If the frequency of motion compensation is low, the frequency of operation of the circuit that performs motion compensation can be reduced, so power consumption can be reduced. Since it is possible to reduce the possibility of creating an intermediate image that does not have an image, the quality of the image can be improved. As such conversion ratios, in the range where n is 10 or less, for example, 1, 2, 3, 3/2, 4,
5, 5/2, 6, 7, 7/2, 8, 9, 9/2, 10. Using such a conversion ratio makes it possible to improve image quality and reduce power consumption, particularly when intermediate images obtained by motion compensation are used as interpolated images. This is because when m is 2, the number of images that can be displayed without performing motion compensation on the input image data is relatively large (there are only 1/2 of the total number of input image data). ,
This is because the frequency of performing motion compensation decreases. Furthermore, when m is 1, the number of images that can be displayed without performing motion compensation on the input image data is large (equal to the total number of input image data), and motion compensation is not performed. be. On the other hand, the larger m is, the more the intermediate images created by highly accurate motion compensation can be used, so there is an advantage that the motion of the images can be made smoother.

If the display device is a liquid crystal display device, the conversion ratio can be determined according to the response time of the liquid crystal element. Here, the response time of the liquid crystal element is the time from when the voltage applied to the liquid crystal element is changed until the liquid crystal element responds. When the response time of the liquid crystal element varies depending on the amount of change in the voltage applied to the liquid crystal element, the average value of the response times in a plurality of representative voltage changes can be used. Alternatively, the response time of the liquid crystal element is MPRT (Movin
g Picture Response Time).
Then, the frame rate conversion can determine the conversion ratio so that the image display period becomes close to the response time of the liquid crystal element. Specifically, it is preferable that the response time of the liquid crystal element is the time from the sum of the cycle of the input image data and the reciprocal of the conversion ratio to about half of this value. By doing so, it is possible to set the image display cycle to match the response time of the liquid crystal element, so that the image quality can be improved. For example, when the response time of the liquid crystal element is 4 milliseconds or more and 8 milliseconds or less, double-speed driving (120 Hz driving) can be used. This is because the image display period of 120 Hz drive is approximately 8 milliseconds, and half of the image display period of 120 Hz drive is approximately 4 milliseconds. Similarly, for example, when the response time of the liquid crystal element is 3 milliseconds or more and 6 milliseconds or less, triple speed driving (180 Hz driving) can be performed, and the response time of the liquid crystal element is 5 milliseconds.
When the response time of the liquid crystal element is 2 milliseconds or more and 4 milliseconds or less, 4 times speed driving (240 Hz driving) can be used when the response time of the liquid crystal element is 2 milliseconds or more and 4 milliseconds or less. ), and when the response time of the liquid crystal element is 6 milliseconds or more and 12 milliseconds or less, 1
. A 25-fold speed drive (80 Hz drive) can be used. The same applies to other drive frequencies.

Note that the conversion ratio can also be determined by a trade-off between the quality of moving images, power consumption, and manufacturing cost. That is, by increasing the conversion ratio, the quality of moving images can be improved, while by decreasing the conversion ratio, power consumption and manufacturing costs can be reduced. That is, each conversion ratio in the range where n is 10 or less has the following advantages.

When the conversion ratio is 1, the quality of moving images can be improved more than when the conversion ratio is less than 1, and power consumption and manufacturing cost can be reduced more than when the conversion ratio is greater than 1. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is approximately one time the period of the input image data.

When the conversion ratio is 2, the quality of moving images can be improved more than when the conversion ratio is less than 2, and power consumption and manufacturing cost can be reduced more than when the conversion ratio is greater than 2. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about half the cycle of the input image data.

When the conversion ratio is 3, the quality of moving images can be improved more than when the conversion ratio is less than 3, and power consumption and manufacturing cost can be reduced more than when the conversion ratio is greater than 3. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about ⅓ times the period of the input image data.

When the conversion ratio is 3/2, the moving image quality can be improved more than when the conversion ratio is less than 3/2, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 3/2. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about ⅔ times the period of the input image data.

When the conversion ratio is 4, the quality of moving images can be improved more than when the conversion ratio is less than 4, and power consumption and manufacturing cost can be reduced more than when the conversion ratio is greater than 4. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about 1/4 times the period of the input image data.

When the conversion ratio is 4/3, the moving image quality can be improved more than when the conversion ratio is less than 4/3, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 4/3. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 3/4 times the cycle of the input image data.

When the conversion ratio is 5, the quality of moving images can be improved more than when the conversion ratio is less than 5, and power consumption and manufacturing cost can be reduced more than when the conversion ratio is greater than 5. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about ⅕ times the cycle of the input image data.

When the conversion ratio is 5/2, the moving image quality can be improved more than when the conversion ratio is less than 5/2, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 5/2. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 2/5 times the cycle of the input image data.

When the conversion ratio is 5/3, the moving image quality can be improved more than when the conversion ratio is less than 5/3, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 5/3. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 3/5 times the cycle of the input image data.

When the conversion ratio is 5/4, the moving image quality can be improved more than when the conversion ratio is less than 5/4, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 5/4. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about 4/5 times the period of the input image data.

When the conversion ratio is 6, the quality of moving images can be improved more than when the conversion ratio is less than 6, and power consumption and manufacturing cost can be reduced more than when the conversion ratio is greater than 6. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 1/6 times the cycle of the input image data.

When the conversion ratio is 6/5, the quality of moving images can be improved more than when the conversion ratio is less than 6/5, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 6/5. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 5/6 times the cycle of the input image data.

When the conversion ratio is 7, the moving image quality can be improved more than when the conversion ratio is less than 7, and power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 7. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 1/7 times the period of the input image data.

When the conversion ratio is 7/2, the moving image quality can be improved more than when the conversion ratio is less than 7/2, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 7/2. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 2/7 times the period of the input image data.

When the conversion ratio is 7/3, the moving image quality can be improved more than when the conversion ratio is less than 7/3, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 7/3. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 3/7 times the cycle of the input image data.

When the conversion ratio is 7/4, it is possible to improve the quality of the moving image as compared to when the conversion ratio is less than 7/4, and it is possible to reduce power consumption and manufacturing cost as compared to when the conversion ratio is greater than 7/4. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 4/7 times the period of the input image data.

When the conversion ratio is 7/5, the moving image quality can be improved more than when the conversion ratio is less than 7/5, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 7/5. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 5/7 times the period of the input image data.

When the conversion ratio is 7/6, the moving image quality can be improved more than when the conversion ratio is less than 7/6, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 7/6. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 6/7 times the period of the input image data.

When the conversion ratio is 8, the quality of moving images can be improved more than when the conversion ratio is less than 8, and power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 8. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about ⅛ times the cycle of the input image data.

When the conversion ratio is 8/3, it is possible to improve the quality of the moving image as compared to when the conversion ratio is less than 8/3, and it is possible to reduce power consumption and manufacturing cost compared to when the conversion ratio is greater than 8/3. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 3/8 times the cycle of the input image data.

When the conversion ratio is 8/5, the moving image quality can be improved more than when the conversion ratio is less than 8/5, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 8/5. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 5/8 times the cycle of the input image data.

When the conversion ratio is 8/7, the moving image quality can be improved more than when the conversion ratio is less than 8/7, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 8/7. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 7/8 times the cycle of the input image data.

When the conversion ratio is 9, the moving image quality can be improved more than when the conversion ratio is less than 9, and power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 9. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 1/9 times the cycle of the input image data.

When the conversion ratio is 9/2, the moving image quality can be improved more than when the conversion ratio is less than 9/2, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 9/2. Furthermore, since m is small, power consumption can be reduced while obtaining high image quality. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 2/9 times the cycle of the input image data.

When the conversion ratio is 9/4, the moving image quality can be improved more than when the conversion ratio is less than 9/4, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 9/4. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 4/9 times the cycle of the input image data.

When the conversion ratio is 9/5, the moving image quality can be improved more than when the conversion ratio is less than 9/5, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 9/5. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 5/9 times the cycle of the input image data.

When the conversion ratio is 9/7, the moving image quality can be improved more than when the conversion ratio is less than 9/7, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 9/7. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 7/9 times the cycle of the input image data.

When the conversion ratio is 9/8, the moving image quality can be improved more than when the conversion ratio is less than 9/8, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 9/8. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about 8/9 times the cycle of the input image data.

When the conversion ratio is 10, the video quality can be improved more than when the conversion ratio is less than 10,
Power consumption and manufacturing costs can be reduced compared to when the conversion ratio is greater than 10. Furthermore, m
is small, so power consumption can be reduced while obtaining high image quality. Furthermore, by applying the present invention to a liquid crystal display device in which the response time of the liquid crystal element is about 1/10 times the cycle of the input image data,
Image quality can be improved.

When the conversion ratio is 10/3, the quality of moving images can be improved more than when the conversion ratio is less than 10/3, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 10/3. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about 3/10 times the cycle of the input image data.

When the conversion ratio is 10/7, the quality of moving images can be improved more than when the conversion ratio is less than 10/7, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 10/7. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 7/10 times the cycle of the input image data.

When the conversion ratio is 10/9, the moving image quality can be improved more than when the conversion ratio is less than 10/9, and the power consumption and manufacturing cost can be reduced more than when the conversion ratio is more than 10/9. Furthermore, since m is large, the motion of the image can be made smoother. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 9/10 times the cycle of the input image data.

It is clear that each conversion ratio in the range where n is greater than 10 also has similar advantages.

Next, as a second step, an image according to the input image data or each image whose frame rate has been converted to an arbitrary rational number (n/m) times in the first step (referred to as an original image) ) to create a plurality of different images (sub-images) and present the plurality of sub-images continuously in time. By doing so, it is possible to make the human eye perceive that one original image is displayed, even though a plurality of images are actually presented.

Here, among the sub-images created from one original image, the sub-image displayed first is called the first sub-image. Here, it is assumed that the timing for displaying the first sub-image is the same as the timing for displaying the original image determined in the first step. on the other hand,
A sub-image displayed after that is called a second sub-image. The timing of displaying the second sub-image can be determined arbitrarily regardless of the timing of displaying the original image determined in the first step. Note that the image to be actually displayed is the image created from the original image by the method in the second step. Various images can be used as the original image for creating the sub-image. Note that the number of sub-images is not limited to two, and may be greater than two. In the second step, the number of sub-images is denoted as J (J is an integer equal to or greater than 2). At this time, the sub-image displayed at the same timing as the timing for displaying the original image determined in the first step is called the first sub-image, and the sub-images displayed after that are called the displayed sub-images. The second sub-image, the third sub-image, . . .
, J-th sub-image.

There are various methods for creating a plurality of sub-images from one original image, but the main methods are as follows. One method is to use the original image as it is as a sub-image. One is a method of distributing the brightness of the original image to a plurality of sub-images. One method is to use an intermediate image obtained by motion compensation as a sub-image.

Here, the method of distributing the brightness of the original image to a plurality of sub-images can be further divided into a plurality of methods. Main methods include the following methods. One is a method of making at least one sub-image a black image (referred to as a black insertion method). One is
When the brightness of the original image is divided into a plurality of ranges and the brightness in each range is controlled, only one sub-image out of all the sub-images is used (referred to as the time-division gradation control method). ). One sub-image is a bright image obtained by changing the gamma value of the original image, and the other sub-image is a dark image obtained by changing the gamma value of the original image (referred to as a gamma interpolation method). ).

A brief description of each of the above methods is provided. In the method of using the original image as it is as the sub-image, the original image is used as it is as the first sub-image. Furthermore, the original image is used as it is as the second sub-image. By using this method, it is possible to reduce power consumption and manufacturing costs because there is no need to operate a circuit for creating a new sub-image or to use the circuit itself. In particular, in the liquid crystal display device, the first
It is preferable to use this method after performing frame rate conversion using the intermediate image obtained by motion compensation as an interpolated image in step 2). This is because, by using intermediate images obtained by motion compensation as interpolated images, the movement of moving images is smoothed, and the same image is repeatedly displayed. This is because obstacles such as trailing and afterimages can be reduced.

Next, a method for setting the brightness of the image and the length of the period during which the sub-images are displayed in the method of distributing the brightness of the original image to a plurality of sub-images will be described in detail. Note that J represents the number of sub-images and is an integer of 2 or more. A lowercase j is distinguished from an uppercase J. Assume that j is an integer of 1 or more and J or less.
L is the pixel brightness in normal hold driving, T is the period of the original image data,
Let L _j be the brightness of the pixel in the j- _th sub-image, and T _j be the length of the period during which the j-th sub-image is displayed _. sum up to j = J (L
_1T1 + _L2T2 +...+ _LJTJ ) is preferably equal to _the product of L and T (LT ₎ (the brightness _remains unchanged). Furthermore, the sum of T _j from j=1 to j=J (T ₁ +T ₂ + . . . +T _J ) is equal to T (the display cycle of the original image is maintained). preferable. Here, the fact that the brightness is unchanged and that the display cycle of the original image is maintained is called a sub-image distribution condition.

Among the methods of distributing the brightness of the original image to a plurality of sub-images, the black insertion method is a method of making at least one sub-image a black image. By doing so, the display method can be a pseudo-impulse type, so that it is possible to prevent the quality of moving images from being degraded due to the display method being of the hold type. Here, it is preferable to comply with the sub-image distribution condition in order to prevent the brightness of the displayed image from decreasing due to the insertion of the black image. However, if the situation is such that a decrease in the brightness of the displayed image is acceptable (dark surroundings, etc.), or if the user has set the brightness of the displayed image to be acceptable, the sub-image Not subject to distribution conditions. For example, one sub-image may be the same as the original image, and the other sub-image may be a black image. In this case, power consumption can be reduced compared to when sub-image distribution conditions are followed. Furthermore, in the liquid crystal display device, when one of the sub-images is made by increasing the overall brightness of the original image without limiting the maximum brightness, the brightness of the backlight can be increased. , the sub-image distribution condition may be realized. In this case, the sub-image distribution condition can be satisfied without controlling the voltage value written to the pixels, so the operation of the image processing circuit can be omitted, and power consumption can be reduced.

The black insertion method is characterized by setting _Lj of all pixels to 0 in any one sub-image. By doing so, the display method can be a pseudo-impulse type, so that it is possible to prevent the quality of moving images from deteriorating due to the display method being of the hold type.

Among the methods of distributing the brightness of the original image to a plurality of sub-images, the time-division gradation control method divides the brightness of the original image into a plurality of ranges, and when controlling the brightness in each range, all This is a method using only one sub-image among the sub-images of . By doing so, the display method can be pseudo-impulse type without lowering the brightness, so that it is possible to prevent the quality of moving images from deteriorating due to the hold type display method.

As a method of dividing the brightness of the original image into a plurality of ranges, the maximum value of brightness (L _max ) is
There is a method of dividing by the number of sub-images. For example, in a display device that can adjust brightness from 0 to L _max in 256 steps (gradation 0 to gradation 255), if the number of sub-images is 2, gradation 0 to gradation 127 is displayed, the brightness of one sub-image is adjusted in the range of gradation 0 to 255, while the brightness of the other sub-image is set to gradation 0,
When displaying gradation 128 to gradation 255, the brightness of one of the sub-images is set to gradation 255.
On the other hand, this method adjusts the brightness of the other sub-image within the range of 0 to 255 gradations. By doing this, the human eye can perceive the image as if the original image was displayed, and the motion image can be simulated to be of the impulse type. can be prevented. Note that the number of sub-images may be greater than two. For example, if the number of sub-images is 3, the brightness level of the original image (gradation 0 to gradation 2)
55) is divided into three. Depending on the number of brightness levels in the original image and the number of sub-images, the number of brightness levels may not be divisible by the number of sub-images. Even if the number of brightness levels is not exactly the same, it may be distributed as appropriate.

It should be noted that the time-division gradation control method is also preferable because an image similar to the original image can be displayed without a decrease in brightness by satisfying the sub-image distribution condition.

Among methods for distributing the brightness of an original image to multiple sub-images, the gamma interpolation method makes one of the sub-images a brighter image obtained by changing the gamma characteristics of the original image, and converts the other sub-image to the gamma of the original image. This is a method of making a dark image with changed characteristics. By doing so, the display method can be pseudo-impulse type without lowering the brightness, so that it is possible to prevent the quality of moving images from deteriorating due to the hold type display method. Here, the gamma characteristic is the degree of brightness with respect to the level of brightness (gradation). Normally, the gamma characteristic is adjusted so as to be close to linear. This is because a smooth gradation can be obtained by making the change in brightness proportional to the gradation, which is the level of brightness. In the gamma interpolation method, the gamma characteristic of one of the sub-images is deviated from linear and adjusted so that it becomes brighter than linear in the intermediate brightness (halftone) area (an image in which the halftone is brighter than it should be). )
. Then, the gamma characteristic of the other sub-image is also deviated from linear, and similarly adjusted so that the halftone region becomes darker than linear (the halftone is darker than it should be). where the amount by which one sub-image is made brighter than linear and the amount by which the other sub-image is made darker than linear is
It is preferable to make all gradations substantially equal. By doing so, it is possible to perceive to the human eye as if the original image was displayed, and it is possible to prevent the quality of the moving image from deteriorating due to the hold type. Note that the number of sub-images may be greater than two. For example, if the number of sub-images is 3, adjust the gamma characteristics of each of the 3 sub-images so that the sum of the amount of lightening from linear and the sum of the amount of darkening from linear are approximately equal. good.

It should be noted that even in the gamma interpolation method, if the sub-image distribution condition is satisfied, an image similar to the original image can be displayed without a decrease in brightness, which is preferable. moreover,
In the gamma interpolation method, since the change in the brightness _Lj of each sub-image with respect to the gradation follows the gamma curve, each sub-image by itself can display the gradation smoothly.
This has the advantage that the final image quality perceived by the human eye is also improved.

A method of using an intermediate image obtained by motion compensation as a sub-image is a method in which one of the sub-images is an intermediate image obtained by motion compensation from the previous and subsequent images. By doing so, the motion of the image can be smoothed, so the quality of the moving image can be improved.

Next, the relationship between the timing of displaying the sub-image and the method of creating the sub-image will be described. The timing of displaying the first sub-image is the same as the timing of displaying the original image determined in the first step, and the timing of displaying the second sub-image is the same as the timing of displaying the original image determined in the first step. Although it is possible to arbitrarily determine the timing of displaying the image, the sub-image itself may be changed according to the timing of displaying the second sub-image. By doing so, even if the timing of displaying the second sub-image is changed in various ways, it is possible for the human eye to perceive the original image as if it had been displayed. Specifically, when the timing for displaying the second sub-image is advanced, the first sub-image is made brighter and the second sub-image is made brighter.
can be made darker. Furthermore, if the timing for displaying the second sub-image is delayed, the first sub-image can be made darker and the second sub-image can be made brighter. This is because the brightness perceived by the human eye varies depending on the length of the image display period. More specifically, the brightness perceived by the human eye becomes brighter as the image display period becomes longer, and becomes darker as the image display period becomes shorter. That is, by advancing the timing of displaying the second sub-image, the length of the period of displaying the first sub-image is shortened and the length of the period of displaying the second sub-image is lengthened. As they are, the first sub-image is dark and the second sub-image is bright, which are perceived by the human eye. As a result, an image different from the original image will be perceived by the human eye.
can be made lighter and the second sub-image darker. Similarly, the second
By delaying the timing of displaying the sub-image of , the length of the period of displaying the first sub-image becomes longer, and the length of the period of displaying the second sub-image becomes shorter. A sub-image can be darker and a second sub-image can be lighter.

Based on the above description, the processing procedure in the second step is shown below.
As procedure 1, a method for creating a plurality of sub-images from one original image is determined. More specifically, the method of creating a plurality of sub-images includes a method of using the original image as it is as a sub-image, a method of distributing the brightness of the original image to a plurality of sub-images, and a method of converting an intermediate image obtained by motion compensation into a sub-image. can be selected from the method used as
As procedure 2, the number J of sub-images is determined. Note that J is an integer of 2 or more.
As step 3, the pixel brightness L _j in the j th sub-image and the length of time T _j during which the j th sub-image is displayed are determined according to the method selected in step 1 . By procedure 3, the length of the period during which each sub-image is displayed and the brightness of each pixel included in each sub-image are specifically determined.
As step 4, the original image is processed and actually displayed according to the items determined in steps 1 to 3 respectively.
In step 5, the target original image is moved to the next original image. Then, return to step 1.

Note that the mechanism for executing the procedure in the second step may be implemented in the device, or may be determined in advance at the design stage of the device. If the device is equipped with a mechanism for executing the procedure in the second step, it becomes possible to switch the driving method so that the optimum operation according to the situation is performed. The conditions here refer to the content of the image data, the environment inside and outside the device (temperature, humidity, air pressure, light, sound, magnetic field, electric field, radiation dose,
altitude, acceleration, movement speed, etc.), user settings, software version, etc. On the other hand, if the mechanism for executing the procedure in the second step is determined in advance at the design stage of the device, the optimum driving circuit can be used for each driving method, and the mechanism is already determined. As a result, a reduction in manufacturing costs can be expected due to the effect of mass production.

Next, various driving methods determined by the procedure in the second step will be described in detail by specifically showing the values of n and m in the first step, respectively.

In procedure 1 of the second step, when the method of using the original image as it is as the sub-image is selected, the driving method is as follows.

i-th (i is a positive integer) image data;
and the i+1th image data are sequentially prepared at a constant cycle T,
The period T is divided into J (J is an integer equal to or greater than 2) sub-image display periods,
The i-th image data is data that allows each of a plurality of pixels to have a unique brightness L,
The j-th (j is an integer of 1 or more and J or less) sub-image is formed by juxtaposing a plurality of pixels each having a unique brightness _Lj , and is displayed for _the j-th sub-image display period Tj. is an image,
A method of driving a display device that satisfies sub-image distribution conditions for the L, the T, the L _j , and the T _{j ,} comprising:
For all j, the brightness L _j of each pixel contained in the j-th sub-image is characterized by L _j =L for each pixel.
Here, the original image data created in the first step can be used as the image data that is sequentially prepared at the constant cycle T. FIG. That is, all the display patterns mentioned in the explanation of the first step can be combined with the driving method described above.

Then, when the number of sub-images J is determined to be 2 in procedure 2 of the second step, and T ₁ =T ₂ =T/2 in procedure 3, the driving method is shown in FIG. It will be something like
In FIG. 71, the horizontal axis represents time, and the vertical axis represents different cases of n and m used in the first step.

For example, in the first step, when n=1, m=1, that is, when the conversion ratio (n/m) is 1, the driving method shown at n=1, m=1 in FIG. Become. At this time, the display frame rate is twice the frame rate of the input image data (double speed drive). Specifically, for example, if the input frame rate is 60 Hz, the display frame rate is 120 Hz (120 Hz drive). Then, an image is displayed twice in succession for one piece of input image data. Here, in the case of double-speed drive, the quality of moving images can be improved more than when the frame rate is less than double speed, and power consumption and manufacturing cost can be reduced more than when the frame rate is greater than double speed. Furthermore, in procedure 1 of the second step,
By selecting the method of using the original image as a sub-image as it is, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the device, so the power consumption and the manufacturing cost of the device can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, it is effective to combine the AC drive and the 120 Hz drive of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 120 Hz, the frequency of the AC drive is set to an integer multiple or an integer fraction (for example, 30 Hz, 60 Hz).
, 120 Hz, 240 Hz, etc.), it is possible to reduce the flicker that appears due to AC driving to a level that is not perceived by the human eye. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about half the period of the input image data.

Further, for example, in the first step n=2, m=1, i.e. the conversion ratio (n/m
) is 2, the drive method shown at n=2, m=1 in FIG. 71 is used. At this time, the display frame rate is four times the frame rate of the input image data (quadruple speed drive). Specifically, for example, if the input frame rate is 60 Hz, the display frame rate is 240 Hz (240 Hz drive). Then, an image is displayed four times in succession for one input image data. At this time, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. Here, in the case of quadruple-speed drive, the quality of moving images can be improved more than when the frame rate is less than quadruple speed, and the power consumption and manufacturing cost can be reduced more than when the frame rate is greater than quadruple speed. Furthermore, in the procedure 1 of the second step, by selecting the method of using the original image as a sub-image as it is, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the device. Therefore, power consumption and manufacturing cost of the device can be reduced. Furthermore, when the display device is an active matrix liquid crystal display device,
Since the problem of lack of write voltage due to dynamic capacitance can be avoided, a remarkable image quality improvement effect can be brought about, especially against obstacles such as trailing of moving images and afterimages. Furthermore, it is effective to combine the AC drive and the 240 Hz drive of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 240 Hz, the frequency of the AC drive is set to an integral multiple or a fraction of that (for example, 30 Hz, 60 Hz, 120 Hz, 240 Hz, etc.). It can be reduced to the extent that it is imperceptible to the human eye. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 1/4 times the period of the input image data.

Further, for example, in the first step n=3, m=1, i.e. the transformation ratio (n/m
) is 3, the drive method shown at n=3, m=1 in FIG. 71 is used. At this time, the display frame rate is six times the frame rate of the input image data (sixfold speed driving). Specifically, for example, if the input frame rate is 60 Hz, the display frame rate is 360 Hz (360 Hz drive). Then, an image is displayed continuously six times for one input image data. At this time, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. Here, in the case of 6× speed driving, the quality of moving images can be improved more than when the frame rate is lower than 6× speed, and power consumption and manufacturing cost can be reduced more than when the frame rate is higher than 6× speed. Furthermore, in the procedure 1 of the second step, by selecting the method of using the original image as a sub-image as it is, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the device. Therefore, power consumption and manufacturing cost of the device can be reduced. Furthermore, when the display device is an active matrix liquid crystal display device,
Since the problem of lack of write voltage due to dynamic capacitance can be avoided, a remarkable image quality improvement effect can be brought about, especially against obstacles such as trailing of moving images and afterimages. Furthermore, it is effective to combine the AC driving and the 360 Hz driving of the liquid crystal display device. That is, by setting the drive frequency of the liquid crystal display device to 360 Hz and setting the frequency of the AC drive to an integer multiple or a fraction of that (for example, 30 Hz, 60 Hz, 120 Hz, 180 Hz, etc.), the flicker caused by the AC drive is It can be reduced to the extent that it is imperceptible to the human eye. Furthermore, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about 1/6 times the period of the input image data.

Further, for example, in the first step n=3, m=2, i.e. the transformation ratio (n/m
) is 3/2, the drive method shown at n=3, m=2 in FIG. 71 is used.
At this time, the display frame rate is three times the frame rate of the input image data (triple speed drive). Specifically, for example, if the input frame rate is 60 Hz, the display frame rate is 180 Hz (180 Hz drive). Then, an image is displayed three times in succession for one piece of input image data. At this time, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. where 3
In the case of double-speed drive, the quality of moving images can be improved more than when the frame rate is less than triple speed, and power consumption and manufacturing cost can be reduced more than when the frame rate is more than triple speed. Furthermore, in the procedure 1 of the second step, by selecting the method of using the original image as a sub-image as it is, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the apparatus. Therefore, power consumption and manufacturing cost of the device can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, it is also effective to combine AC driving and 180 Hz driving of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 180 Hz, the frequency of the AC drive is set to an integer multiple or a fraction of that (for example, 30 Hz, 60 Hz, 120 Hz, 180 Hz, etc.). It can be reduced to the extent that it is imperceptible to the human eye. Further, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about ⅓ times the period of the input image data.

Further, for example, in the first step n=4, m=1, i.e. the conversion ratio (n/m
) is 4, the drive method shown at n=4 and m=1 in FIG. 71 is used. At this time, the display frame rate is eight times the frame rate of the input image data (8-fold speed drive). Specifically, for example, if the input frame rate is 60 Hz, the display frame rate is 480 Hz (480 Hz drive). Then, an image is displayed eight times consecutively for one input image data. At this time, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. Here, in the case of 8× speed driving, the quality of moving images can be improved more than when the frame rate is less than 8× speed, and power consumption and manufacturing cost can be reduced more than when the frame rate is more than 8× speed. Furthermore, in the procedure 1 of the second step, by selecting the method of using the original image as a sub-image as it is, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the device. Therefore, power consumption and manufacturing cost of the device can be reduced. Furthermore, when the display device is an active matrix liquid crystal display device,
Since the problem of lack of write voltage due to dynamic capacitance can be avoided, a remarkable image quality improvement effect can be brought about, especially against obstacles such as trailing of moving images and afterimages. Furthermore, it is effective to combine the AC drive and the 480 Hz drive of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 480 Hz, by setting the frequency of the AC drive to an integer multiple or a fraction of that (for example, 30 Hz, 60 Hz, 120 Hz, 240 Hz, etc.), the flicker caused by the AC drive is It can be reduced to the extent that it is imperceptible to the human eye. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about ⅛ times the cycle of the input image data.

Further, for example, in the first step n=4, m=3, i.e. the conversion ratio (n/m
) is 4/3, the drive method shown at n=4 and m=3 in FIG. 71 is used.
At this time, the display frame rate is 8/3 times (8
/3 times speed drive). Specifically, for example, if the input frame rate is 60 Hz, the display frame rate is 160 Hz (160 Hz drive). Then, an image is displayed eight times in succession with respect to three pieces of input image data. At this time, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. Here, in the case of 8/3 times speed driving, the quality of moving images can be improved more than when the frame rate is less than 8/3 times speed, and power consumption and manufacturing cost can be reduced more than when the frame rate is more than 8/3 times speed. Furthermore, in the procedure 1 of the second step, by selecting the method of using the original image as a sub-image as it is, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the device. Therefore, power consumption and manufacturing cost of the device can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages.
Furthermore, it is also effective to combine AC driving and 160 Hz driving of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 160 Hz, the frequency of the AC drive is set to an integer multiple or a fraction of that (for example, 40 Hz, 80 Hz, 160 Hz, 320 Hz, etc.). It can be reduced to the extent that it is imperceptible to the human eye. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about 3/8 times the cycle of the input image data.

Further, for example, in the first step n=5, m=1, i.e. the conversion ratio (n/m
) is 5, the drive method shown at n=5, m=1 in FIG. 71 is used. At this time, the display frame rate is 10 times the frame rate of the input image data (10-fold speed drive). Specifically, for example, if the input frame rate is 60 Hz, the display frame rate is 600 Hz (600 Hz drive). Then, an image is displayed ten times in succession for one input image data. At this time, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. here,
In the case of 10x speed drive, the quality of moving images can be improved more than when the frame rate is less than 10x speed, and power consumption and manufacturing cost can be reduced more than when the frame rate is more than 10x speed. Furthermore, in the procedure 1 of the second step, by selecting the method of using the original image as a sub-image as it is, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the apparatus. Therefore, power consumption and manufacturing cost of the device can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, it is effective to combine the AC driving and the 600 Hz driving of the liquid crystal display device. That is, by setting the drive frequency of the liquid crystal display device to 600 Hz and setting the frequency of the AC drive to an integer multiple or a fraction of that (for example, 30 Hz, 60 Hz, 100 Hz, 120 Hz, etc.), the flicker caused by the AC drive is reduced to It can be reduced to the extent that it is imperceptible to the human eye. Furthermore, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about 1/10 times the cycle of the input image data.

Further, for example, in the first step n=5, m=2, i.e. the transformation ratio (n/m
) is 5/2, the drive method shown at n=5 and m=2 in FIG. 71 is used.
At this time, the display frame rate is five times the frame rate of the input image data (five times speed drive). Specifically, for example, if the input frame rate is 60 Hz, the display frame rate is 300 Hz (300 Hz drive). Then, an image is displayed five times in succession for one input image data. At this time, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. Here, in the case of quintuple-speed drive, the quality of moving images can be improved more than when the frame rate is less than quintuple speed, and power consumption and manufacturing cost can be reduced more than when the frame rate is more than quintuple speed. Furthermore, the second
By selecting the method of using the original image as a sub-image as it is in step 1 of step 1, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the device. Power consumption and device manufacturing costs can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, it is also effective to combine AC driving and 300 Hz driving of the liquid crystal display device. That is, while setting the drive frequency of the liquid crystal display device to 300 Hz, the frequency of the AC drive is set to an integer multiple or an integral fraction of the 300 Hz.
For example, by setting it to 30 Hz, 50 Hz, 60 Hz, 100 Hz, etc.), it is possible to reduce flicker that appears due to AC driving to a level that is not perceived by human eyes. Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about ⅕ times the cycle of the input image data.

In this way, in procedure 1 of the second step, a method of using the original image as it is as a sub-image is selected,
In procedure 2 in the second step, the number of sub-images is determined to be 2,
In procedure 3 in the second step, if it is determined that T1=T2=T/2, the first
Since the display frame rate can be further doubled with respect to the frame rate conversion at the conversion ratio determined by the values of n and m in step 2, the quality of moving images can be further improved. Furthermore, it is possible to improve the quality of the moving image as compared with the display frame rate lower than the display frame rate, and reduce power consumption and manufacturing cost as compared with the display frame rate higher than the display frame rate.
Furthermore, in the procedure 1 of the second step, by selecting the method of using the original image as a sub-image as it is, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the device. Therefore, power consumption and manufacturing cost of the device can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of shortage of write voltage due to dynamic capacitance can be avoided, so that a remarkable image quality improvement effect can be brought about against troubles such as trailing of moving images and afterimages. moreover,
By increasing the drive frequency of the liquid crystal display device and setting the frequency of the AC drive to an integer multiple or a fraction of that, the flicker that appears due to the AC drive can be reduced to a level not perceptible to the human eye. Furthermore, the response time of the liquid crystal element (
Image quality can be improved by applying it to a liquid crystal display device having a conversion ratio of about 1/(twice the conversion ratio).

Although detailed explanation is omitted, it is clear that similar advantages are obtained even in cases other than the conversion ratios mentioned above. For example, in the range where n is 10 or less, in addition to the above,
n=5, m=3, that is, conversion ratio (n/m)=5/3 (10/3 double speed drive, 200 Hz)
,
n = 5, m = 4, that is, conversion ratio (n/m) = 5/4 (5/2 double speed drive, 150 Hz),
n = 6, m = 1, that is, conversion ratio (n/m) = 6 (12x speed drive, 720 Hz),
n=6, m=5, that is, conversion ratio (n/m)=6/5 (12/5 double speed drive, 144 Hz)
,
n=7, m=1, that is, conversion ratio (n/m)=7 (14x speed drive, 840 Hz),
n = 7, m = 2, that is, conversion ratio (n/m) = 7/2 (seven times speed drive, 420 Hz),
n=7, m=3, that is, conversion ratio (n/m)=7/3 (14/3 double speed drive, 280 Hz)
,
n=7, m=4, that is, conversion ratio (n/m)=7/4 (7/2 double speed drive, 210 Hz),
n=7, m=5, that is, conversion ratio (n/m)=7/5 (14/5 double speed drive, 168 Hz)
,
n=7, m=6, that is, conversion ratio (n/m)=7/6 (7/3 double speed drive, 140 Hz),
n = 8, m = 1, that is, conversion ratio (n/m) = 8 (16x speed drive, 960 Hz),
n=8, m=3, that is, conversion ratio (n/m)=8/3 (16/3 double speed drive, 320 Hz)
,
n=8, m=5, that is, conversion ratio (n/m)=8/5 (16/5 double speed drive, 192 Hz)
,
n=8, m=7, that is, conversion ratio (n/m)=8/7 (16/7 double speed drive, 137 Hz)
,
n = 9, m = 1, that is, conversion ratio (n/m) = 9 (18x speed drive, 1080 Hz),
n=9, m=2, that is, the conversion ratio (n/m)=9/2 (9-fold speed drive, 540 Hz),
n = 9, m = 4, that is, conversion ratio (n/m) = 9/4 (9/2 double speed drive, 270 Hz),
n=9, m=5, that is, conversion ratio (n/m)=9/5 (18/5 double speed drive, 216 Hz)
,
n=9, m=7, that is, conversion ratio (n/m)=9/7 (18/7 double speed drive, 154 Hz)
,
n = 9, m = 8, that is, conversion ratio (n/m) = 9/8 (9/4 double speed drive, 135 Hz),
n=10, m=1, that is, conversion ratio (n/m)=10 (20x speed drive, 1200 Hz),
n = 10, m = 3, that is, conversion ratio (n/m) = 10/3 (20/3 double speed drive, 400H
z),
n=10, m=7, that is, conversion ratio (n/m)=10/7 (20/7 double speed drive, 171H
z),
n=10, m=9, that is, conversion ratio (n/m)=10/9 (20/9 double speed drive, 133H
z),
Combinations of the above are conceivable. Note that the notation of frequency is an example when the input frame rate is 60 Hz, and for other input frame rates, the value obtained by multiplying the input frame rate by twice the respective conversion ratio becomes the drive frequency.

It should be noted that when n is an integer greater than 10, specific numbers of n and m are not listed, but it is clear that the procedure in the second step can be applied to various n and m. .

If J=2, it is particularly effective if the conversion ratio in the first step is greater than 2. This is because if the number of sub-images is relatively small, such as J=2, in the second step, the conversion ratio in the first step can be increased accordingly. Such conversion ratios are 3, 4, 5, 5/2, 6, 7
, 7/2, 7/3, 8, 8/3, 9, 9/2, 9/4, 10, 10/3.
When the display frame rate after the first step is such a value, by setting J=3 or more, there are advantages due to the small number of sub-images in the second step (reduction of power consumption and manufacturing cost, etc.). , and the advantages (improvement in moving image quality, reduction in flicker, etc.) due to a large final display frame rate can be achieved at the same time.

Here, the number J of sub-images is determined to be 2 in procedure 2, and T ₁ =
Although the case where it is determined that T ₂ =T/2 has been described, it is clearly not limited to this.

For example, if in procedure 3 in the second step it was determined that T ₁ <T ₂ , then the first sub-image can be made brighter and the second sub-image can be made darker. Furthermore, the second
If it is determined in procedure 3 in step 2 that T ₁ >T ₂ , then the first sub-image can be made darker and the second sub-image can be made lighter. By doing so, the original image can be properly perceived by the human eye, and at the same time, the display can be pseudo-impulse driven, thereby improving the quality of moving images. However, if the method of using the original image as the sub-image as it is is selected in step 1 as in the driving method described above, the sub-image may be displayed as it is without changing the brightness of the sub-image. This is because the same image is used as the sub-image in this case, so the original image can be properly displayed regardless of the display timing of the sub-image.

Furthermore, it is clear that in procedure 2 the number of sub-images J may be determined to be other values than two. In this case, the display frame rate can be further J times higher than the frame rate conversion with the conversion ratio determined by the values of n and m in the first step, so that the quality of the moving image can be further improved. becomes possible. Furthermore, it is possible to improve the quality of the moving image as compared with the display frame rate lower than the display frame rate, and reduce power consumption and manufacturing cost as compared with the display frame rate higher than the display frame rate. Furthermore, in the procedure 1 of the second step, by selecting the method of using the original image as a sub-image as it is, the operation of the circuit that creates the intermediate image by motion compensation can be stopped or the circuit itself can be omitted from the apparatus. Therefore, power consumption and manufacturing cost of the device can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, by increasing the drive frequency of the liquid crystal display device and setting the frequency of the AC drive to an integral multiple or to a fraction of that, it is possible to reduce the flicker caused by the AC drive to a level not perceptible to the human eye. can. Furthermore, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is approximately (1/(J times the conversion ratio)) times the cycle of the input image data.

For example, when J=3, in particular, the video quality can be improved more than when the number of sub-images is less than 3, and the power consumption and manufacturing cost can be reduced more than when the number of sub-images is more than 3. have advantages. Furthermore, the response time of the liquid crystal element is (1
The image quality can be improved by applying it to a liquid crystal display device having a conversion ratio of approximately /(three times the conversion ratio).

Furthermore, for example, J=4, in particular, can improve video quality over sub-images less than 4, and reduce power consumption and manufacturing costs over sub-images over 4. have the advantage of being able to Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is approximately (1/(4 times the conversion ratio)) times the period of the input image data.

In addition, for example, J=5 can result in better video quality, especially when the number of sub-images is less than 5, and lower power consumption and manufacturing costs than when the number of sub-images is greater than 5. have the advantage of being able to Furthermore, the image quality can be improved by applying it to a liquid crystal display device in which the response time of the liquid crystal element is about (1/(five times the conversion ratio)) times the period of the input image data.

Moreover, J other than those listed above have similar advantages.

When J=3 or more, the conversion ratio in the first step can take various values. Especially when the conversion ratio in the first step is relatively small (2 or less), J= 3
The above is effective. This is because if the display frame rate after the first step is relatively low, J can be increased accordingly in the second step. Such conversion ratios are 1, 2, 3/2, 4/3,
5/3, 5/4, 6/5, 7/4, 7/5, 7/6, 8/7, 9/5, 9/7, 9/8,
10/7 and 10/9. Among them, the conversion ratios are 1, 2, 3/2, 4/3, 5/
The case of 3,5/4 is illustrated in FIG. Thus, when the display frame rate after the first step is a relatively small value, by setting J=3 or more, the advantage of the small display frame rate in the first step (reduction of power consumption and manufacturing cost) is achieved. reduction, etc.) and the advantages of a large final display frame rate (improvement in moving image quality, reduction in flicker, etc.) can be made compatible.

Next, another example of the driving method determined by the procedure in the second step will be described.

In procedure 1 of the second step, when the black insertion method is selected among the methods of distributing the brightness of the original image to a plurality of sub-images, the driving method is as follows.

i-th (i is a positive integer) image data;
and the i+1th image data are sequentially prepared at a constant cycle T,
The period T is divided into J (J is an integer equal to or greater than 2) sub-image display periods,
The i-th image data is data that allows each of a plurality of pixels to have a unique brightness L,
The j-th sub-image (j is an integer of 1 or more and J or less) is constructed by juxtaposing a plurality of pixels each having a unique brightness _Lj , and is displayed for the j-th sub-image display period _Tj . is an image,
A method of driving a display device that satisfies sub-image distribution conditions for the L, the T, the L _j , and the T _{j ,} comprising:
In at least one j, the brightness L _j of all pixels contained in the j-th sub-image is L _j
=0.
Here, the original image data created in the first step can be used as the image data sequentially prepared at the constant cycle T. FIG. That is, all the display patterns mentioned in the explanation of the first step can be combined with the above driving method.

It is clear that the above driving method can be implemented in combination with various n and m used in the first step.

Then, when the number of sub-images J is determined to be 2 in procedure 2 of the second step, and T ₁ =T ₂ =T/2 in procedure 3, the driving method is shown in FIG. It will be something like
Since the features and advantages of the driving method shown in FIG. 71 (display timing for various n and m) have already been described, detailed description is omitted here. Of the methods for distributing the .sub.s into a plurality of sub-images, it is clear that the black insertion method has similar advantages. For example, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. Furthermore, when the display frame rate is high, the quality of moving images can be improved, and when the display frame rate is low, power consumption and manufacturing costs can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of shortage of write voltage due to dynamic capacitance can be avoided, so that a remarkable image quality improvement effect can be brought about against troubles such as trailing of moving images and afterimages. Furthermore, flicker that appears due to AC driving can be reduced to the extent that it is not perceived by the human eye.

Among the methods for distributing the brightness of the original image to a plurality of sub-images in procedure 1 of the second step, a characteristic advantage of selecting the black insertion method is that an intermediate image is created by motion compensation. Because the operation of the circuit can be stopped or the circuit itself can be omitted from the device,
It is possible to reduce the power consumption and the manufacturing cost of the device. Furthermore, since a pseudo-impulse-type display method can be used regardless of the gradation values included in the image data, the quality of moving images can be improved.

Here, the number J of sub-images is determined to be 2 in procedure 2, and T ₁ =
Although the case where it is determined that T ₂ =T/2 has been described, it is clearly not limited to this.

For example, if in procedure 3 in the second step it was determined that T ₁ <T ₂ , then the first sub-image can be made brighter and the second sub-image can be made darker. Furthermore, the second
If it is determined in procedure 3 in step 2 that T ₁ >T ₂ , then the first sub-image can be made darker and the second sub-image can be made lighter. By doing so, the original image can be properly perceived by the human eye, and at the same time, the display can be pseudo-impulse driven, thereby improving the quality of moving images. However, as in the above driving method, if the black insertion method is selected among the methods for distributing the brightness of the original image to a plurality of sub-images in step 1, the brightness of the sub-images is not changed. can be displayed as is. because,
This is because, in this case, if the brightness of the sub-image is not changed, the overall brightness of the original image will be darkened and displayed. That is, by positively using this method for controlling the brightness of the display device, it becomes possible to control the brightness while improving the quality of moving images.

Furthermore, it is clear that in procedure 2 the number of sub-images J may be determined to be other values than two. Since the advantages in this case have already been described, a detailed explanation is omitted here. It is clear that the selected case has similar advantages. For example, the response time of the liquid crystal element is the period of the input image data (1/(J times the conversion ratio)
), the image quality can be improved by applying it to a liquid crystal display device which is approximately twice as large.

Next, another example of the driving method determined by the procedure in the second step will be described.

In procedure 1 of the second step, when the time-division gradation control method is selected among the methods of distributing the brightness of the original image to a plurality of sub-images, the driving method is as follows.

i-th (i is a positive integer) image data;
and the i+1th image data are sequentially prepared at a constant cycle T,
The period T is divided into J (J is an integer equal to or greater than 2) sub-image display periods,
The i-th image data is data that allows each of a plurality of pixels to have a unique brightness L,
The intrinsic brightness L has a maximum value of L _max ,
The j-th (j is an integer of 1 or more and J or less) sub-image is formed by juxtaposing a plurality of pixels each having a unique brightness _Lj , and is displayed for _the j-th sub-image display period Tj. is an image,
A method of driving a display device that satisfies sub-image distribution conditions for the L, the T, the L _j , and the T _{j ,} comprising:
In displaying the inherent brightness L, (j−1)×L _max /J to J×L _max
The brightness adjustment in the brightness range of /J is performed by adjusting the brightness in only one sub-image display period among the J sub-image display periods.
Here, the original image data created in the first step can be used as the image data that is sequentially prepared at the constant cycle T. FIG. That is, all the display patterns mentioned in the explanation of the first step can be combined with the driving method described above.

It is obvious that the driving method described above can be implemented in combination with various n and m used in the first step.

Then, when the number of sub-images J is determined to be 2 in procedure 2 of the second step and T ₁ =T ₂ =T/2 in procedure 3, the driving method is shown in FIG. It will be something like
Since the features and advantages of the driving method shown in FIG. 71 (display timing for various n and m) have already been described, detailed description is omitted here. It is clear that the same advantages are obtained when the time-division gradation control method is selected among the methods of distributing the .times..times..times..times. For example, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. Furthermore, when the display frame rate is high, the quality of moving images can be improved, and when the display frame rate is low, power consumption and manufacturing costs can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, flicker that appears due to AC driving can be reduced to a level that is not perceived by the human eye.

In procedure 1 of the second step, among the methods for distributing the brightness of the original image to a plurality of sub-images, the characteristic advantage of selecting the time-division grayscale control method is that the intermediate image is can be stopped or the circuit itself can be omitted from the device, so that the power consumption and the manufacturing cost of the device can be reduced. moreover,
Since a pseudo-impulse-type display method can be used, the quality of moving images can be improved, and the brightness of the display device does not decrease, so that power consumption can be further reduced.

Here, the number J of sub-images is determined to be 2 in procedure 2, and T ₁ =
Although the case where it is determined that T ₂ =T/2 has been described, it is clearly not limited to this.

For example, if in procedure 3 in the second step it was determined that T ₁ <T ₂ , then the first sub-image can be made brighter and the second sub-image can be made darker. Furthermore, the second
In step 3, if it is determined that T ₁ >T ₂ , then the first sub-image can be made darker and the second sub-image can be made lighter. By doing so, the original image can be properly perceived by the human eye, and at the same time, the display can be pseudo-impulse driven, so that the quality of moving images can be improved. By doing so, the original image can be properly perceived by the human eye, and at the same time, the display can be pseudo-impulse driven, so that the quality of moving images can be improved.

Furthermore, it is clear that in procedure 2 the number of sub-images J may be determined to be other values than two. Since the advantages of this case have already been described, a detailed explanation is omitted here. Clearly, the control strategy chosen has similar advantages. For example, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about (1/(J times the conversion ratio)) times the cycle of the input image data.

Next, another example of the driving method determined by the procedure in the second step will be described.

In procedure 1 of the second step, when the gamma interpolation method is selected among the methods of distributing the brightness of the original image to a plurality of sub-images, the driving method is as follows.

i-th (i is a positive integer) image data;
and the i+1th image data are sequentially prepared at a constant cycle T,
The period T is divided into J (J is an integer equal to or greater than 2) sub-image display periods,
The i-th image data is data that allows each of a plurality of pixels to have a unique brightness L,
The j-th (j is an integer of 1 or more and J or less) sub-image is formed by juxtaposing a plurality of pixels each having a unique brightness _Lj , and is displayed for _the j-th sub-image display period Tj. is an image,
A method of driving a display device that satisfies sub-image distribution conditions for the L, the T, the L _j , and the T _{j ,} comprising:
In each sub-image, the characteristics of the change in brightness with respect to gradation are calculated by shifting from linear to the sum of the amount of brightness shifted from linear to brighter and the sum of the amount of brightness shifted from linear to darker. , are approximately the same for all gradations.
Here, the original image data created in the first step can be used as the image data that is sequentially prepared at the constant cycle T. FIG. That is, all the display patterns mentioned in the explanation of the first step can be combined with the driving method described above.

It is obvious that the driving method described above can be implemented in combination with various n and m used in the first step.

Then, when the number of sub-images J is determined to be 2 in procedure 2 of the second step and T ₁ =T ₂ =T/2 in procedure 3, the driving method is shown in FIG. It will be something like
Since the features and advantages of the driving method shown in FIG. 71 (display timing for various n and m) have already been described, detailed description is omitted here. It is clear that the gamma interpolation method has similar advantages when the method of distributing the .times..times..times..times..times..times..times..times..times..times..times..times. For example, if the interpolated image in the first step is an intermediate image obtained by motion compensation, the motion of the moving image can be smoothed, so the quality of the moving image can be significantly improved. Furthermore, when the display frame rate is high, the quality of moving images can be improved, and when the display frame rate is low, power consumption and manufacturing costs can be reduced. Furthermore, when the display device is an active matrix type liquid crystal display device, the problem of insufficient write voltage due to dynamic capacitance can be avoided, so that a particularly remarkable image quality improvement effect can be obtained against obstacles such as trailing of moving images and afterimages. Furthermore, flicker that appears due to AC driving can be reduced to a level that is not perceived by the human eye.

Among the methods for distributing the brightness of the original image to a plurality of sub-images in procedure 1 of the second step, the characteristic advantage of selecting the gamma interpolation method is that an intermediate image is created by motion compensation. Since the operation of the circuit can be stopped or the circuit itself can be omitted from the device, the power consumption and the manufacturing cost of the device can be reduced. Furthermore, since a pseudo-impulse-type display method can be used regardless of the gradation values included in the image data, the quality of moving images can be improved. Further, sub-images may be obtained by directly gamma-converting the image data. In this case, there is an advantage that the gamma value can be controlled variously depending on the magnitude of motion of the moving image. Further, the image data may not be directly gamma-converted, but may be configured to obtain sub-images with changed gamma values by changing the reference voltage of a digital-to-analog conversion circuit (DAC). In this case, since the image data is not directly gamma-converted, the circuit that performs gamma conversion can be stopped or the circuit itself can be omitted from the device, so that the power consumption and the manufacturing cost of the device can be reduced. . Furthermore, in the gamma interpolation method, since the change in brightness _Lj of each sub-image with respect to gradation follows a gamma curve, each sub-image can display gradation smoothly by itself, and finally human This has the advantage that the quality of the image perceived by the human eye is also improved.

Here, the number J of sub-images is determined to be 2 in procedure 2, and T ₁ =
Although the case where it is determined that T ₂ =T/2 has been described, it is clearly not limited to this.

For example, if in procedure 3 in the second step it was determined that T ₁ <T ₂ , then the first sub-image can be made brighter and the second sub-image can be made darker. Furthermore, the second
In step 3, if it is determined that T ₁ >T ₂ , then the first sub-image can be made darker and the second sub-image can be made lighter. By doing so, the original image can be properly perceived by the human eye, and at the same time, the display can be pseudo-impulse driven, so that the quality of moving images can be improved. In addition, as in the above driving method, step 1
3, when the gamma method is selected among the methods of distributing the brightness of the original image to a plurality of sub-images, the gamma value may be changed when changing the brightness of the sub-images. That is, the gamma value may be determined according to the display timing of the second sub-image. By doing so, the circuit that changes the brightness of the entire image can be stopped or the circuit itself can be omitted from the device, so that the power consumption and the manufacturing cost of the device can be reduced.

Furthermore, it is clear that in procedure 2 the number of sub-images J may be determined to be other values than two. Since the advantages of this case have already been described, a detailed explanation is omitted here. Clearly, the control strategy chosen has similar advantages. For example, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about (1/(J times the conversion ratio)) times the cycle of the input image data.

Next, another example of the driving method determined by the procedure in the second step will be described in detail.

In procedure 1 of the second step, a method of using intermediate images obtained by motion compensation as sub-images is selected,
In procedure 2 in the second step, the number of sub-images is determined to be 2,
In procedure 3 in the second step, if it is determined that T1=T2=T/2, the second
The driving method determined by the procedure in step 1 is as follows.

i-th (i is a positive integer) image data;
and the i+1th image data are sequentially prepared at a constant cycle T,
a k-th (k is a positive integer) image;
a k+1-th image;
A driving method for a display device for sequentially displaying a k+2-th image and an image at an interval of 1/2 times the period of the original image data,
the k-th image is displayed according to the i-th image data;
the k+1-th image is displayed according to image data corresponding to a motion obtained by multiplying the motion from the i-th image data to the i+1-th image data by 1/2;
The k+2-th image is displayed according to the i+1-th image data.
Here, the original image data created in the first step can be used as the image data that is sequentially prepared at the constant cycle T. FIG. That is, all the display patterns mentioned in the explanation of the first step can be combined with the driving method described above.

It is obvious that the driving method described above can be implemented in combination with various n and m used in the first step.

A characteristic advantage of selecting the method of using the intermediate image obtained by motion compensation as a sub-image in procedure 1 of the second step is that the intermediate image obtained by motion compensation is used in procedure 1 of the first step. The point is that when an interpolated image is used, the method of obtaining the intermediate image used in the first step can be used in the second step as it is. In other words, the circuit that obtains the intermediate image by motion compensation can be used not only in the first step but also in the second step, so that the circuit can be used effectively and the processing efficiency can be improved. In addition, since the movement of images can be made smoother, the quality of moving images can be further improved.

Here, the number J of sub-images is determined to be 2 in procedure 2, and T ₁ =
Although the case where it is determined that T ₂ =T/2 has been described, it is clearly not limited to this.

For example, if in procedure 3 in the second step it was determined that T ₁ <T ₂ , then the first sub-image can be made brighter and the second sub-image can be made darker. Furthermore, the second
In step 3, if it is determined that T ₁ >T ₂ , then the first sub-image can be made darker and the second sub-image can be made lighter. By doing so, the original image can be properly perceived by the human eye, and at the same time, the display can be pseudo-impulse driven, so that the quality of moving images can be improved. By doing so, the original image can be properly perceived by the human eye, and at the same time, the display can be pseudo-impulse driven, so that the quality of moving images can be improved. In addition, as in the above driving method, in procedure 2,
If the method of using an intermediate image obtained by motion compensation as a sub-image is selected, it is not necessary to change the brightness of the sub-image. This is because the image in the intermediate state is complete as an image by itself, so even if the display timing of the second sub-image changes, the image perceived by the human eye does not change. In this case, the circuit that changes the brightness of the entire image can be stopped or the circuit itself can be omitted from the device, so power consumption and manufacturing cost of the device can be reduced.

Furthermore, it is clear that in procedure 2 the number of sub-images J may be determined to be other values than two. Since the advantage in that case has already been described, detailed description is omitted here. However, the same applies when the method of using the intermediate image obtained by motion compensation as a sub-image is selected in procedure 1 of the second step. Clearly, it has significant advantages. For example, the image quality can be improved by applying to a liquid crystal display device in which the response time of the liquid crystal element is about (1/(J times the conversion ratio)) times the cycle of the input image data.

Next, a specific example of a frame rate conversion method when the input frame rate and the display frame rate are different will be described with reference to FIG. In the method shown in FIGS. 73A to 73C, it is assumed that the circular area on the image is an area whose position changes depending on the frame, and the triangular area on the image is an area whose position hardly changes depending on the frame. there is however,
This is an example for explanation, and the displayed image is not limited to this. The methods of FIGS. 73A to 73C can be applied to various images.

FIG. 73A shows a case where the display frame rate is twice the input frame rate (the conversion ratio is 2). A conversion ratio of 2 has the advantage that the quality of moving images can be improved over a conversion ratio of less than 2. Furthermore, when the conversion ratio is 2, there is an advantage that power consumption and manufacturing cost can be reduced as compared with the case where the conversion ratio is greater than 2. Figure 73 (
A) schematically shows how the displayed image changes over time, with the horizontal axis representing time. Here, the image of interest is referred to as the p-th image (p is a positive integer). Then, the image displayed next to the focused image is the (p+1)th image,
An image displayed in front of the focused image is referred to as the (p-1)th image, and for the sake of convenience, how far it is displayed from the focused image is indicated. It is assumed that An image 7301 is the pth image, an image 7302 is the (p+1)th image, and an image 730
3 is the (p+2)th image, image 7304 is the (p+3)th image, and image 7305 is the (p+3)th image.
4) image. A period Tin represents the cycle of the input image data. Since FIG. 73A shows a case where the conversion ratio is 2, the period Tin is double the period from the display of the p-th image to the display of the (p+1)-th image. be the length.

Here, the (p+1)th image 7302 is obtained from the pth image 7301 to the (p+2)th image 7301 .
By detecting the amount of change in the images up to 303, the image may be created so as to have an intermediate state between the p-th image 7301 and the (p+2)-th image 7303. FIG. In FIG. 73A, an area (circular area) whose position changes with the frame and an area (triangular area) whose position hardly changes with the frame represent the state of the image in the intermediate state. That is, the position of the circular area in the (p+1)-th image 7302 is the position of the p-th image 7301
and the position in the (p+2)th image 7303 . In other words, the (p+1)th image 7302 is obtained by performing motion compensation and interpolating image data. In this way, smooth display can be achieved by performing motion compensation on an object that moves on the image and interpolating the image data.

Furthermore, the (p+1)-th image 7302 is an image created so as to be in an intermediate state between the p-th image 7301 and the (p+2)-th image 7303, and the luminance of the image is controlled according to a certain rule. may A certain rule is, for example, the p-th image 73 as shown in FIG.
01 is L, and the (p+1)-th image 7302 is Lc, there may be a relationship of L>Lc between L and Lc. Desirably, 0.1L<Lc<0.
There may be a relationship of 8L. More preferably, there may be a relationship of 0.2L<Lc<0.5L. Alternatively, conversely, L and Lc may have a relationship of L<Lc. Desirably, there may be a relationship of 0.1Lc<L<0.8Lc. More preferably, 0
. There may be a relationship of 2Lc<L<0.5Lc. By doing so, the display can be pseudo-impulse type, so that the afterimage of the eyes can be suppressed.

Note that typical luminance of an image will be described later in detail with reference to FIG.

Thus, there are two different causes for motion blur (image motion is not smooth,
and eye persistence), motion blur can be significantly reduced.

Furthermore, the (p+3)th image 7304 may also be created from the (p+2)th image 7303 and the (p+4)th image 7305 using a similar method. That is, the (p
+3) image 7304 is the (p+2)th image 7303 to the (p+4)th image 7305
By detecting the amount of change in the image up to the (p+2)th image 7303 and the (p+4)th image 7303
It may be an image created so as to be in an intermediate state of the image 7305 of , and furthermore, an image in which the brightness of the image is controlled according to a certain rule.

FIG. 73B shows a case where the display frame rate is three times the input frame rate (the conversion ratio is 3). FIG. 73B schematically shows how the displayed image changes over time, with the horizontal axis representing time. Image 7311 is the pth image, Image 7312 is the (p+1)th image, Image 7313 is the (p+2)th image, Image 7314 is the (p+3)th image, Image 7315 is the (p+4)th image, Image 7316 is the (p+5)th image, image 7
Assume that 317 is the (p+6)th image. A period Tin represents the cycle of the input image data. Note that since FIG. 73B shows the case where the conversion ratio is 3, the period Tin is
The period from when the p-th image is displayed to when the (p+1)-th image is displayed is three times as long as the period.

Here, the (p+1)th image 7312 and the (p+2)th image 7313 are obtained by detecting the amount of change in the images from the pth image 7311 to the (p+3)th image 7314. and (p+3)-th image 7314 may be an image created so as to be in an intermediate state. In FIG. 73B, an image in an intermediate state is represented by an area (circular area) whose position changes depending on the frame and an area (triangular area) whose position hardly changes depending on the frame. That is, the (p+1)th image 7312 and the (p+1)th image 7312
2) The position of the circular area in the image 7313 is the position in the p-th image 7311,
It is the middle position between the positions in the (p+3)th image 7314 . Specifically, when the amount of movement of the circular region detected from the p-th image 7311 and the (p+3)th image 7314 is X, the position of the circular region in the (p+1)th image 7312 is It may be a position displaced by about (⅓)X from the position in the p-th image 7311 . Furthermore, the position of the circular area in the (p+2)th image 7313 may be a position displaced by about (2/3)X from the position in the pth image 7311 . That is, the (p+1)th image 7
312 and the (p+2)th image 7313 are obtained by performing motion compensation and interpolating the image data. In this way, smooth display can be achieved by performing motion compensation on an object that moves on the image and interpolating the image data.

Furthermore, the (p+1)-th image 7312 and the (p+2)-th image 7313 are created so as to have an intermediate state between the p-th image 7311 and the (p+3)-th image 7314, and the brightness of the image is fixed. It may be an image controlled by the rule of A certain rule is, for example,
3(B), the representative luminance of the p-th image 7311 is L, and the (p+1)-th image 731
2 is Lc1, and the typical luminance of the (p+2)th image 7313 is Lc2.
There may be a relationship that Desirably, there may be a relationship of 0.1L<Lc1=Lc2<0.8L. More desirably, there may be a relationship of 0.2L<Lc=Lc2<0.5L. Or conversely, in L, Lc1, Lc2, L<Lc1 or L<Lc2
Alternatively, there may be a relationship of Lc1=Lc2. Desirably, 0.1Lc1=0.1L
There may be a relationship of c2<L<0.8Lc1=0.8Lc2. More preferably
There may be a relationship of 0.2Lc1=0.2Lc2<L<0.5Lc1=0.5Lc2. By doing so, the display can be pseudo-impulse type, so that the afterimage of the eyes can be suppressed. Alternatively, images with varying brightness may alternately appear. By doing so, the period in which the luminance changes can be shortened, so that flicker can be reduced.

Thus, there are two different causes for motion blur (image motion is not smooth,
and eye persistence), motion blur can be significantly reduced.

Further, the (p+4)th image 7315 and the (p+5)th image 7316 may also be created from the (p+3)th image 7314 and the (p+6)th image 7317 using a similar method. That is, the (p+4)th image 7315 and the (p+5)th image 7315
16 detects the amount of change in the image from the (p+3)th image 7314 to the (p+6)th image 7317, resulting in an intermediate state between the (p+3)th image 7314 and the (p+6)th image 7317. The image may be an image created as described above, and further, an image in which the brightness of the image is controlled according to a certain rule.

When the method of FIG. 73B is used, the display frame rate is high, so the movement of the image can follow the movement of the eyes well, and the movement of the image can be displayed smoothly. can be greatly reduced.

In FIG. 73(C), the display frame rate is 1.5 times the input frame rate (conversion ratio 1.5).
). FIG. 73C schematically shows how the displayed image changes over time, with the horizontal axis representing time. Image 7321 is the p-th image, image 732
2 is the (p+1)th image, image 7323 is the (p+2)th image, and image 7324 is the (p+1)th image.
3) is the image. Note that the image 7325 is input image data and may be used to create the (p+1)th image 7322 and the (p+2)th image 7323, although it does not have to be actually displayed. A period Tin represents the cycle of the input image data. Note that FIG. 73C shows the case where the conversion ratio is 1.5, so the period Tin is
The period from the display of the p-th image to the display of the (p+1)-th image is 1.5 times longer than the period.

Here, the (p+1)th image 7322 and the (p+2)th image 7323 are obtained by detecting the amount of change in the image from the pth image 7321 to the (p+3)th image 7324 via the image 7325. , p-th image 7321 and (p+3)-th image 7324 . In FIG. 73C, an area (circular area) whose position changes with the frame and an area (triangular area) whose position hardly changes with the frame represent the state of the image in the intermediate state. That is, the positions of the circular regions in the (p+1)th image 7322 and the (p+2)th image 7323 are the positions of the pth image 7323
321 and the position in the (p+3)th image 7324 . That is, the (p+1)-th image 7322 and the (p+2)-th image 7323 are obtained by performing motion compensation and interpolating image data. In this way, smooth display can be achieved by performing motion compensation on an object that moves on the image and interpolating the image data.

Furthermore, the (p+1)-th image 7322 and the (p+2)-th image 7323 are created so as to have an intermediate state between the p-th image 7321 and the (p+3)-th image 7324, and the brightness of the image is fixed. It may be an image controlled by the rule of A certain rule is, for example,
3(C), the representative luminance of the p-th image 7321 is L, and the (p+1)-th image 732
2 is Lc1, and the typical luminance of the (p+2)th image 7323 is Lc2.
There may be a relationship that Desirably, there may be a relationship of 0.1L<Lc1=Lc2<0.8L. More desirably, there may be a relationship of 0.2L<Lc=Lc2<0.5L. Or conversely, in L, Lc1, Lc2, L<Lc1 or L<Lc2
Alternatively, there may be a relationship of Lc1=Lc2. Desirably, 0.1Lc1=0.1L
There may be a relationship of c2<L<0.8Lc1=0.8Lc2. More preferably
There may be a relationship of 0.2Lc1=0.2Lc2<L<0.5Lc1=0.5Lc2. By doing so, the display can be pseudo-impulse type, so that the afterimage of the eyes can be suppressed. Alternatively, images with varying brightness may alternately appear. By doing so, the period in which the luminance changes can be shortened, so that flicker can be reduced.

Thus, there are two different causes for motion blur (image motion is not smooth,
and eye persistence), motion blur can be significantly reduced.

Note that when the method in FIG. 73C is used, the display frame rate is low, so the time for writing signals to the display device can be lengthened. Therefore, since the clock frequency of the display device can be reduced, power consumption can be reduced. Moreover, since the processing speed of motion compensation can be slowed down, power consumption can be reduced.

Next, with reference to FIG. 74, typical luminance of an image will be described. 74(A) to (D)
) schematically shows how the displayed image changes over time, with the horizontal axis representing time. FIG. 74(E) is an example of a method for measuring the luminance of an image within a certain region.

As a method of measuring the luminance of an image, there is a method of individually measuring the luminance of each pixel constituting the image. Using this method, it is possible to measure the brightness of the image details precisely.

However, since the method of individually measuring the luminance of each pixel constituting an image requires a great deal of labor, another method may be used. Another method of measuring the luminance of an image is to focus on a region within the image and measure the average luminance of that region. This method makes it possible to easily measure the luminance of an image. In the present embodiment, the brightness obtained by the method of measuring the average brightness of a certain area in the image is called the representative brightness of the image for convenience.

Then, in order to obtain the representative brightness of the image, which area in the image should be focused on will be described below.

FIG. 74A shows an example of a method of using the luminance of an area (triangular area) whose position is almost unchanged with respect to image changes as the representative luminance of the image. The period Tin is the cycle of the input image data, the image 7401 is the pth image, the image 7402 is the (p+1)th image, the image 7403 is the (p+2)th image, and the first region 7404 is the luminance in the pth image 7401. The measurement area, the second area 7405, is the luminance measurement area, the third area 7405, in the (p+1)th image 7402
06 represents the luminance measurement area in the (p+2)th image 7403, respectively. Here, the first to third regions may be assumed to have substantially the same spatial position within the device.
That is, by measuring the representative luminance of the image in the first to third regions, it is possible to obtain the temporal change in the representative luminance of the image.

By measuring the representative brightness of the image, it is possible to determine whether the display is pseudo-impulsive. For example, let the luminance measured in the first region 7404 be L, the second
When Lc is the luminance measured in the area 7405 of , it can be said that the display is pseudo-impulse type if Lc<L. In such a case, it can be said that the quality of the moving image is improved.

In the luminance measurement area, the image quality can be improved if the representative luminance change amount (relative luminance) of the image with respect to time changes is within the following range. As the relative luminance, for example, the first region 7404 and the second region 7405, the second region 7405 and the third region 7405
406, for each of the first region 7404 and the third region 7406 can be the ratio of the lower luminance to the higher luminance. In other words, when the amount of change in typical luminance of an image with respect to time is 0, the relative luminance is 100%. And the relative brightness is 8
If it is 0% or less, the quality of moving images can be improved. In particular, when the relative luminance is 50% or less, the quality of moving images can be significantly improved. Furthermore, if the relative brightness is 10% or more, power consumption can be reduced and flicker can be suppressed. In particular, when the relative luminance is 20% or more, power consumption and flicker can be significantly reduced. That is, if the relative luminance is 10% or more and 80
% or less, it is possible to improve the quality of moving images and reduce power consumption and flicker. Furthermore, when the relative luminance is 20% or more and 50% or less, the quality of moving images can be significantly improved, and power consumption and flicker can be significantly reduced.

FIG. 74B shows an example of a method of measuring the brightness of the regions divided into tiles and using the average value as the representative brightness of the image. The period Tin is the cycle of the input image data, and the image 7411
is the pth image, the image 7412 is the (p+1)th image, the image 7413 is the (p+2)th image, the first region 7414 is the brightness measurement region in the pth image 7411, the second region 7415
is the luminance measurement area in the (p+1)th image 7412, and the third area 7416 is the (p+2
) in the image 7413, respectively. Here, the first to third
may be assumed to be substantially the same in terms of spatial position within the device. That is, by measuring the representative luminance of the image in the first to third regions, it is possible to obtain the temporal change in the representative luminance of the image.

By measuring the representative brightness of the image, it is possible to determine whether the display is pseudo-impulsive. For example, if L is the average value of luminance in all regions measured in the first region 7414, and Lc is the average value of luminance in all regions measured in the second region 7415, even if Lc<L In other words, the display can be said to be pseudo-impulse.
In such a case, it can be said that the quality of the moving image is improved.

In the luminance measurement area, the image quality can be improved if the representative luminance change amount (relative luminance) of the image with respect to time changes is within the following range. As the relative luminance, for example, the first region 7414 and the second region 7415, the second region 7415 and the third region 7415
416, for each of the first region 7414 and the third region 7416, can be the ratio of the lower luminance to the higher luminance. In other words, when the amount of change in typical luminance of an image with respect to time is 0, the relative luminance is 100%. And the relative brightness is 8
If it is 0% or less, the quality of moving images can be improved. In particular, when the relative luminance is 50% or less, the quality of moving images can be significantly improved. Furthermore, if the relative brightness is 10% or more, power consumption can be reduced and flicker can be suppressed. In particular, when the relative luminance is 20% or more, power consumption and flicker can be significantly reduced. That is, if the relative luminance is 10% or more and 80
% or less, it is possible to improve the quality of moving images and reduce power consumption and flicker. Furthermore, when the relative luminance is 20% or more and 50% or less, the quality of moving images can be significantly improved, and power consumption and flicker can be significantly reduced.

FIG. 74C shows an example of a method of measuring the luminance in the central area of the image and using the average value as the representative luminance of the image. The period Tin is the period of the input image data, the image 7421 is the pth image, the image 7422 is the (p+1)th image, the image 7423 is the (p+2)th image, and the first region 7424 is the luminance in the pth image 7421. The measurement area, the second area 7425, is the (p
+1) image 7422, and the third area 7426 represents the luminance measurement area in the (p+2)th image 7423, respectively.

By measuring the representative brightness of the image, it is possible to determine whether the display is pseudo-impulsive. For example, let the luminance measured in the first region 7424 be L, the second
When Lc is the luminance measured in the area 7425 of , it can be said that the display is pseudo-impulse type if Lc<L. In such a case, it can be said that the quality of the moving image is improved.

In the luminance measurement area, the image quality can be improved if the representative luminance change amount (relative luminance) of the image with respect to time changes is within the following range. As the relative luminance, for example, the first region 7424 and the second region 7425, the second region 7425 and the third region 7425
426, for each of the first region 7424 and the third region 7426, can be the ratio of the lower luminance to the higher luminance. In other words, when the amount of change in typical luminance of an image with respect to time is 0, the relative luminance is 100%. And the relative brightness is 8
If it is 0% or less, the quality of moving images can be improved. In particular, when the relative luminance is 50% or less, the quality of moving images can be significantly improved. Furthermore, if the relative brightness is 10% or more, power consumption can be reduced and flicker can be suppressed. In particular, when the relative luminance is 20% or more, power consumption and flicker can be significantly reduced. That is, if the relative luminance is 10% or more and 80
% or less, it is possible to improve the quality of moving images and reduce power consumption and flicker. Furthermore, when the relative luminance is 20% or more and 50% or less, the quality of moving images can be significantly improved, and power consumption and flicker can be significantly reduced.

FIG. 74D shows an example of a method of measuring the brightness of a plurality of points sampled from the entire image and using the average value as the representative brightness of the image. the period Tin is the cycle of the input image data;
Image 7431 is the pth image, image 7432 is the (p+1)th image, image 7433 is the (p
+2), the first region 7434 is the brightness measurement region in the pth image 7431, the second region 7435 is the brightness measurement region in the (p+1)th image 7432, the third region 7436
represent the luminance measurement regions in the (p+2)th image 7433, respectively.

By measuring the representative brightness of the image, it is possible to determine whether the display is pseudo-impulsive. For example, if L is the average value of luminance in all regions measured in the first region 7434, and Lc is the average value of luminance in all regions measured in the second region 7435, Lc<L. In other words, the display can be said to be pseudo-impulse.
In such a case, it can be said that the quality of the moving image is improved.

In the luminance measurement area, the image quality can be improved if the representative luminance change amount (relative luminance) of the image with respect to time changes is within the following range. As the relative brightness, for example, the first region 7434 and the second region 7435, the second region 7435 and the third region 7435
436, for each of the first region 7434 and the third region 7436, can be the ratio of the lower luminance to the higher luminance. In other words, when the amount of change in typical luminance of an image with respect to time is 0, the relative luminance is 100%. And the relative brightness is 8
If it is 0% or less, the quality of moving images can be improved. In particular, when the relative luminance is 50% or less, the quality of moving images can be significantly improved. Furthermore, if the relative brightness is 10% or more, power consumption can be reduced and flicker can be suppressed. In particular, when the relative luminance is 20% or more, power consumption and flicker can be significantly reduced. That is, if the relative luminance is 10% or more and 80
% or less, it is possible to improve the quality of moving images and reduce power consumption and flicker. Furthermore, when the relative luminance is 20% or more and 50% or less, the quality of moving images can be significantly improved, and power consumption and flicker can be significantly reduced.

FIG. 74(E) is a diagram showing a method of measuring the luminance measurement area in the diagrams shown in FIGS. 74(A) to (D). A region 7441 is a brightness measurement region of interest, and a point 7442 is a brightness measurement point within the brightness measurement region 7441 . A luminance measuring device with high time resolution may have a small measurement target range. The brightness of the region 7441 may be determined by measuring at a plurality of points without unevenness and averaging the values.

Note that if the image has a combination of the three primary colors R, G, and B, the measured luminance is
, B may be combined, R and G may be combined, G and B may be combined, B and R may be combined, or R, G, and B may be combined. It may be luminance.

Next, a method of detecting motion of an image included in input image data and creating an image in an intermediate state,
and a method of controlling the driving method according to the motion of the image included in the input image data.

An example of a method of detecting motion of an image included in input image data and creating an image in an intermediate state will be described with reference to FIG. FIG. 75A shows a case where the display frame rate is twice the input frame rate (the conversion ratio is 2). FIG. 75A schematically shows a method of detecting motion of an image, with the horizontal axis representing time. The period Tin is the period of the input image data, the image 7501 is the pth image, the image 7502 is the (p+1)th image,
Images 7503 each represent the (p+2)th image. Also, in the image, a first region 7504, a second region 7505, and a third region 750 are shown as time-independent regions.
6 is provided.

First, in the (p+2)th image 7503, the image is divided into a plurality of tiled regions,
Focus on the image data in the third area 7506, which is one of these areas.

Next, in the p-th image 7501, a third region 750 centered on the third region 7506
Focus on the range larger than 6. Here, the third region 7506 centered on the third region 7506
Ranges greater than 506 are data search ranges. The data search range is 7507 in the horizontal direction (X direction) and 7508 in the vertical direction (Y direction). The horizontal range 7507 and vertical range 7508 of the data search range may be ranges obtained by expanding the horizontal range and vertical range of the third area 7506 by about 15 pixels, respectively.

Then, within the data search range, an area having image data most similar to the image data in the third area 7506 is searched. A method of least squares or the like can be used as a search method. Assume that the first area 7504 is derived as the area having the most similar image data as a result of the search.

Next, a vector 7509 is derived as a quantity representing the positional difference between the derived first region 7504 and the third region 7506 . Note that the vector 7509 is called a motion vector.

In the (p+1)th image 7502, the vector 7510 obtained from the motion vector 7509, the image data in the third area 7506 in the (p+2)th image 7503, and the first A second area 7505 is formed by the image data in the area 7504 .

A vector 7510 obtained from the motion vector 7509 is called a displacement vector. Displacement vector 7510 serves to determine the position to form second region 7505 . A second region 7505 is formed at a position separated from the third region 7506 by a displacement vector 7510 . Note that the displacement vector 7510 is obtained by multiplying the motion vector 7509 by a coefficient (1/2).
It may be the amount multiplied by

The image data in the second region 7505 in the (p+1)th image 7502 is the (p+2)th
) and the image data in the first region 7504 in the p-th image 7501 . for example,
The image data in the second region 7505 in the (p+1)th image 7502 is the (p+2)th
) and the image data in the first region 7504 of the p-th image 7501 .

Thus, corresponding to the third region 7506 in the (p+2)th image 7503,
A second region 7505 in the (p+1)th image 7502 can be formed. By performing the above processing on other regions in the (p+2)th image 7503, the (p+2)th
The (p+1)-th image 7503 and the p-th image 7501, which are intermediate between the p+2) image 7503 and the p-th image 7501.
502 can be formed.

FIG. 75B shows a case where the display frame rate is three times the input frame rate (the conversion ratio is 3). FIG. 75B schematically shows a method of detecting motion of an image, with the horizontal axis representing time. The period Tin is the period of the input image data, and the image 7511
represents the pth image, the image 7512 represents the (p+1)th image, the image 7513 represents the (p+2)th image, and the image 7514 represents the (p+3)th image. Also, in the image, a first region 7515, a second region 7516, and a third region 7517 are shown as regions that do not depend on time.
and a fourth region 7518 are provided.

First, in the (p+3)th image 7514, the image is divided into a plurality of tiled regions,
Focus on the image data in the fourth area 7518, which is one of these areas.

Next, in the p-th image 7511, a fourth region 751 centered on the fourth region 7518
Focus on the range larger than 8. Here, the fourth region 7518 centered on the fourth region 7518
Ranges greater than 518 are data search ranges. The data search range is 7519 in the horizontal direction (X direction) and 7520 in the vertical direction (Y direction). The horizontal range 7519 and vertical range 7520 of the data search range may be ranges obtained by expanding the horizontal range and vertical range of the fourth area 7518 by about 15 pixels, respectively.

Then, within the data search range, an area having image data most similar to the image data in the fourth area 7518 is searched. A method of least squares or the like can be used as a search method. Assume that the first area 7515 is derived as the area having the most similar image data as a result of the search.

Next, a vector 7521 is derived as a quantity representing the positional difference between the derived first region 7515 and the fourth region 7518 . Note that the vector 7521 is called a motion vector.

Then, in the (p+1)th image 7512 and the (p+2)th image 7513,
With the vectors 7522 and 7523 obtained from the motion vector 7521, the image data in the fourth area 7518 in the (p+3)th image 7515, and the image data in the first area 7515 in the pth image 7511, A second region 7516 and a third region 7517 are formed.

Here, the vector 7522 obtained from the motion vector 7521 is called the first displacement vector. Also, vector 7523 is called a second displacement vector. The first displacement vector 7522 serves to determine the position that forms the second region 7516 . A second region 7516 is formed at a position spaced apart from the fourth region 7518 by a first displacement vector 7522 . Note that the displacement vector 7522 may be an amount obtained by multiplying the motion vector 7521 by (1/3). Also, the second displacement vector 7523 has a role of determining the position where the third region 7517 is formed. A third region 7517 is formed at a position separated from the fourth region 7518 by a second displacement vector 7523 . Note that the displacement vector 7523 may be the amount obtained by multiplying the motion vector 7521 by (2/3).

The image data in the second region 7516 in the (p+1)th image 7512 is the (p+3)th
) in the fourth region 7518 of the image 7514 and the image data in the first region 7515 of the pth image 7511 . for example,
The image data in the second region 7516 in the (p+1)th image 7512 is the (p+3)th
) and the image data in the first region 7515 in the p-th image 7511 .

The image data in the third region 7517 in the (p+2)th image 7513 is the (p+3)th
) in the fourth region 7518 of the image 7514 and the image data in the first region 7515 of the pth image 7511 . for example,
The image data in the third region 7517 in the (p+2)th image 7513 is the (p+3)th
) and the image data in the first region 7515 in the p-th image 7511 .

Thus, corresponding to the fourth region 7518 in the (p+3)th image 7514,
The second region 7516 in the (p+1)th image 7502 and the (p+2)th image 7
A third region 7517 at 513 can be formed. Note that the above process is
(p+3)th image 751
The (p+1)th image 7512 and the (p+1)th image 7512 and the (p+
2) image 7513 can be formed.

Next, with reference to FIG. 76, an example of a circuit for detecting motion of an image included in input image data and creating an image in an intermediate state will be described. FIG. 76A is a diagram showing the connection relationship between a peripheral driver circuit including a source driver and a gate driver for displaying an image in a display area and a control circuit for controlling the peripheral driver circuit. FIG. 76B is a diagram showing an example of the detailed circuit configuration of the control circuit. FIG. 76C is a diagram showing an example of a detailed circuit configuration of an image processing circuit included in the control circuit. FIG. 76D is a diagram showing another example of the detailed circuit configuration of the image processing circuit included in the control circuit.

As shown in FIG. 76A, the device in this embodiment mode may include a control circuit 7611, a source driver 7612, a gate driver 7613, and a display area 7614. FIG.

Note that the control circuit 7611, the source driver 7612, and the gate driver 7613 may be formed over the same substrate as the display region 7614 is formed.

Note that part of the control circuit 7611, the source driver 7612, and the gate driver 7613 are formed on the same substrate as the substrate on which the display region 7614 is formed.
Other circuits may be formed over a substrate different from the substrate over which the display area 7614 is formed. For example, the source driver 7612 and the gate driver 7613 may be formed on the same substrate on which the display area 7614 is formed, and the control circuit 7611 may be formed as an external IC on a different substrate. Similarly, the gate driver 7613 may be formed on the same substrate on which the display area 7614 is formed, and other circuits may be formed as external ICs on a different substrate. Similarly, the source driver 7612
, the gate driver 7613 and part of the control circuit 7611 may be formed on the same substrate as the substrate on which the display area 7614 is formed, and other circuits may be formed as external ICs on a different substrate.

A control circuit 7611 receives an external image signal 7600, a horizontal synchronizing signal 7601, and a vertical synchronizing signal 7602, and controls an image signal 7603, a source start pulse 7604, a source clock 7605, a gate start pulse 7606, and a gate start pulse 7606. a clock 7607;
may be output.

The source driver 7612 may be configured to receive the image signal 7603 , the source start pulse 7604 and the source clock 7605 and output voltage or current according to the image signal 7603 to the display area 7614 .

A gate driver 7613 generates a gate start pulse 7606 and a gate clock 7607
, and a signal designating the timing of writing the signal output from the source driver 7612 to the display region 7614 may be output.

When the frequency of the external image signal 7600 and the frequency of the image signal 7603 are different, the signal for controlling the timing of driving the source driver 7612 and the gate driver 7613 is also different from the input horizontal synchronizing signal 7601 and vertical synchronizing signal 7602. will have different frequencies. Therefore, in addition to processing the image signal 7603, it is necessary to process signals for controlling the timing of driving the source driver 7612 and the gate driver 7613 as well. The control circuit 7611 may be a circuit having that function. For example, when the frequency of the image signal 7603 is double the frequency of the external image signal 7600, the control circuit 7611 interpolates the image signal included in the external image signal 7600 to generate the image signal 7603 with double the frequency. In addition, the timing control signal is also controlled to double the frequency.

Further, the control circuit 7611 may include an image processing circuit 7615 and a timing generation circuit 7616 as shown in FIG. 76B.

The image processing circuit 7615 may be configured to receive the external image signal 7600 and the frequency control signal 7608 and output the image signal 7603 .

A timing generation circuit 7616 receives a horizontal synchronization signal 7601 and a vertical synchronization signal 7602, and generates a source start pulse 7604, a source clock 7605, a gate start pulse 7606, a gate clock 7607, a frequency control signal 7608, may be output. Note that the timing generation circuit 7616 generates the frequency control signal 760
A memory, register, or the like for holding data for designating the state of 8 may be included. Also, the timing generation circuit 7616 may be configured to receive a signal designating the state of the frequency control signal 7608 from the outside.

The image processing circuit 7615 includes a motion detection circuit 7620, a first memory 7621, a second memory 7622, a third memory 7623, and a luminance control circuit 762 as shown in FIG.
3 and a high speed processing circuit 7625.

The motion detection circuit 7620 may be configured to receive a plurality of image data, detect the motion of the image, and output image data in an intermediate state of the plurality of image data.

The first memory 7621 receives the external video signal 7600 and stores the external video signal 7600.
may be output to the motion detection circuit 7620 and the second memory 7622 while holding for a certain period of time.

The image data output from the first memory 7621 is input to the second memory 7622,
The image data may be output to the motion detection circuit 7620 and the high-speed processing circuit 7625 while holding the image data for a certain period.

The third memory 7623 receives the image data output from the motion detection circuit 7620,
The image data may be output to the brightness control circuit 7624 while holding the image data for a certain period.

The high-speed processing circuit 7625 receives the image data output from the second memory 7622, the image data output from the brightness control circuit 7624, and the frequency control signal 7608, and converts the image data into an image signal 7603. It may be configured to output.

When the frequency of the external image signal 7600 and the frequency of the image signal 7603 are different, the image signal included in the external image signal 7600 may be interpolated by the image processing circuit 7615 to generate the image signal 7603 . The input external image signal 7600 is temporarily stored in the first memory 7
621. At that time, the second memory 7622 holds the image data input in the previous frame. A motion detection circuit 7620 appropriately reads the image data held in the first memory 7621 and the second memory 7622, detects a motion vector from the difference between the two image data, and further generates intermediate state image data. may The generated intermediate state image data is held by the third memory 7623 .

When motion detection circuit 7620 is generating intermediate state image data, high speed processing circuit 762
5 outputs the image data held in the second memory 7622 as an image signal 7603 . After that, the image data held in the third memory 7623 is transferred to the brightness control circuit 7624
is output as an image signal 7603 through . At this time, the second memory 7622 and the third
The frequency with which the memory 7623 of is updated is the same as the frequency of the external image signal 7600, but the frequency of the image signal 7603 output through the high-speed processing circuit 7625 is the same as that of the external image signal 760
It may be different from 0 frequency. Specifically, for example, the frequency of the image signal 7603 can be 1.5 times, 2 times, or 3 times the frequency of the external image signal 7600 . However, it is not limited to this, and various frequencies can be used. Note that the frequency of the image signal 7603 may be designated by the frequency control signal 7608 .

The configuration of the image processing circuit 7615 shown in FIG. 76(D) is obtained by adding a fourth memory 7626 to the configuration of the image processing circuit 7615 shown in FIG. 76(C). In this manner, in addition to the image data output from the first memory 7621 and the image data output from the second memory 7622, the image data output from the fourth memory 7626 is also detected by the motion detection circuit 7620.
By outputting to , it becomes possible to accurately detect the motion of the image.

If the input image data already contains motion vectors due to data compression or the like, for example, MPEG (Moving Picture Expert Gr.
oup) standard, an image in an intermediate state may be generated as an interpolated image using this. At this time, the motion vector generation part included in the motion detection circuit 7620 becomes unnecessary. In addition, since the encoding and decoding processes for the image signal 7623 are simplified, power consumption can be reduced.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each drawing of this embodiment may be applied, combined, replaced, etc. with respect to the content (may be part of) described in the drawing of another embodiment. can be done freely. Furthermore, in the drawings of this embodiment, more drawings can be configured by combining each part with another embodiment.

In addition, the present embodiment is an example of a case where the content (or part of it) described in another embodiment is embodied, an example of a slightly modified case, an example of a partially changed case, and an improved case. An example of the case,
An example of detailed description, an example of application, and an example of related parts are shown. Therefore, the contents described in other embodiments can be freely applied, combined, or replaced with this embodiment.

(Embodiment 11)
In this embodiment, a structure and a manufacturing method of a transistor will be described.

48A and 48B are diagrams showing an example of a structure of a transistor included in a display device according to the present invention and a manufacturing method thereof. FIG. 48A is a diagram showing an example of the structure of a transistor included in a display device according to the invention. 48B to 48G are diagrams showing an example of a method for manufacturing a transistor included in a display device according to the invention.

Note that the structure and manufacturing method of the transistor included in the display device according to the present invention are not limited to those shown in FIGS. 48A and 48B, and various structures and manufacturing methods can be used.

First, an example of a structure of a transistor included in a display device according to the invention is described with reference to FIG. FIG. 48A is a cross-sectional view of transistors having a plurality of different structures. Here, in FIG. 48A, a plurality of transistors having different structures are shown side by side; 48(A), and can be made separately according to need.

Next, each layer forming a transistor included in the display device according to the present invention will be described.

As the substrate 4011, a glass substrate such as barium borosilicate glass or aluminoborosilicate glass, a quartz substrate, a ceramic substrate, a metal substrate containing stainless steel, or the like can be used.
In addition, polyethylene terephthalate (PET), polyethylene naphthalate (PEN)
, polyethersulfone (PES), or flexible synthetic resin such as acrylic. A flexible display device can be manufactured by using a flexible substrate.

The insulating film 4012 functions as a base film. This base film is provided to prevent alkali metals such as Na or alkaline earth metals from the substrate 4011 from adversely affecting the characteristics of the semiconductor element. As the insulating film 4012, an insulating film containing oxygen or nitrogen, such as silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy) (x>y), or silicon nitride oxide (SiNxOy) (x>y). A single layer structure or a laminated structure of these layers can be provided.
For example, when the insulating film 4012 is provided with a two-layer structure, a silicon nitride oxide film is preferably provided as the first insulating film, and a silicon oxynitride film is preferably provided as the second insulating film. In the case where the insulating film 4012 has a three-layer structure, a silicon oxynitride film is provided as the first insulating film, a silicon nitride oxide film is provided as the second insulating film, and an oxynitride film is provided as the third insulating film. A silicon film is preferably provided.

The semiconductor layers 4013, 4014, and 4015 can be made of an amorphous semiconductor or a semi-amorphous semiconductor (SAS). Alternatively, a polycrystalline semiconductor layer may be used. SAS has an intermediate structure between amorphous and crystalline structures (including single crystals and polycrystals),
A semiconductor with a free-energy stable third state, containing crystalline regions with short-range order and lattice strain. 0.5 to 20 in at least some regions in the film
nm crystal regions can be observed, and when silicon is the main component, the Raman spectrum is shifted to the lower wavenumber side than 520 cm ⁻¹ . In X-ray diffraction, diffraction peaks of (111) and (220) are observed, which are believed to be derived from the silicon crystal lattice. At least 1 atomic % or more of hydrogen or halogen is contained as compensation for dangling bonds. SAS is formed by glow-discharge decomposition (plasma CVD) of a material gas. SiH ₄ as material gas, Si ₂ H ₆ , SiH ₂ Cl ₂ , SiHCl ₃ , SiC
l ₄ , SiF ₄ and the like can be used. Alternatively, _GeF4 may be mixed. This material gas may be diluted with H ₂ , or H ₂ and one or more rare gas elements selected from He, Ar, Kr, and Ne. The dilution rate ranges from 2 to 1000 times. The pressure is approximately 0.00.
Range of 1 Pa to 133 Pa, power supply frequency of 1 MHz to 120 MHz, preferably 13 MHz
z~60MHz. The substrate heating temperature may be 300° C. or lower. As impurity elements in the film, oxygen,
Impurities of atmospheric components such as nitrogen and carbon are desirably 1×10 ²⁰ cm ⁻¹ or less,
In particular, the oxygen concentration is 5×10 ¹⁹ /cm ³ or less, preferably 1×10 ¹⁹ /cm ³ or less. Here, an amorphous semiconductor layer is formed using a material (for example, SixGe1-x, etc.) containing silicon (Si) as a main component by using known means (sputtering method, LPCVD method, plasma CVD method, etc.), and the amorphous semiconductor layer is formed. The crystalline semiconductor layer is crystallized by a known crystallization method such as a laser crystallization method, a thermal crystallization method using RTA or a furnace annealing furnace, or a thermal crystallization method using a metal element that promotes crystallization.

The insulating film 4016 is made of silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (Si
OxNy) (x>y), silicon nitride oxide (SiNxOy) (x>y), or a single-layer structure of an insulating film containing oxygen or nitrogen, or a stacked-layer structure thereof.

The gate electrode 4017 can have a single-layer conductive film or a laminated structure of two or three layers of conductive films. As a material for the gate electrode 4017, a known conductive film can be used. For example, tantalum (Ta), titanium (Ti), molybdenum (Mo), tungsten (
W), chromium (Cr), silicon (Si), etc., or a nitride film of said element (typically, a tantalum nitride film, a tungsten nitride film, a titanium nitride film), or a combination of said elements. alloy film (typically Mo-W alloy, Mo-Ta alloy), or
A silicide film of the element (typically, a tungsten silicide film or a titanium silicide film)
etc. can be used. Note that the above-described single film, nitride film, alloy film, silicide film, and the like may be used as a single layer, or may be used as a laminate.

The insulating film 4018 is formed of silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy) (x>y), silicon nitride oxide (SiNxOy) ( A single-layer structure of an insulating film containing oxygen or nitrogen such as x>y) or a film containing carbon such as DLC (diamond-like carbon), or a laminated structure of these can be provided.

The insulating film 4019 is made of siloxane resin, silicon oxide (SiOx), silicon nitride (Si
Nx), silicon oxynitride (SiOxNy) (x>y), silicon oxynitride (SiNxOy) (x
>y) and other insulating films containing oxygen or nitrogen, films containing carbon such as DLC (diamond-like carbon), or organic materials such as epoxy, polyimide, polyamide, polyvinylphenol, benzocyclobutene, and acrylic. , can be provided in a single layer or a laminated structure. Note that the siloxane resin corresponds to a resin containing a Si—O—Si bond. Siloxane has a skeletal structure composed of bonds of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aryl group) is used. A fluoro group can also be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as substituents. Note that in the display device to which the present invention can be applied, the insulating film 4019 can be directly provided so as to cover the gate electrode 4017 without providing the insulating film 4018 .

The conductive film 4023 is a single film of an element such as Al, Ni, W, Mo, Ti, Pt, Cu, Ta, Au, or Mn, a nitride film of the element, an alloy film of a combination of the elements, or , a silicide film of the above element, or the like can be used. For example, as alloys containing a plurality of the elements, an Al alloy containing C and Ti, an Al alloy containing Ni, C and N
An Al alloy containing i, an Al alloy containing C and Mn, or the like can be used. again,
In the case of providing a laminated structure, a structure in which Al is sandwiched between Mo, Ti, or the like can be employed.
By doing so, the resistance of Al to heat and chemical reaction can be improved.

Next, features of each structure are described with reference to cross-sectional views of transistors having a plurality of different structures shown in FIG.

Since the transistor 4001 is a single-drain transistor and can be manufactured by a simple method, it has the advantages of low manufacturing cost and high yield. Here, the semiconductor layer 4
013 and 4015 have different impurity concentrations, the semiconductor layer 4013 functions as a channel region, and the semiconductor layer 4015 functions as a source region and a drain region. By controlling the amount of impurities in this manner, the resistivity of the semiconductor layer can be controlled. In addition, the electrical connection state between the semiconductor layer and the conductive film 4023 can be brought closer to ohmic connection. note that,
As a method of separately forming semiconductor layers with different amounts of impurities, a method of doping the semiconductor layers with impurities using the gate electrode 4017 as a mask can be used.

The transistor 4002 is a transistor in which the gate electrode 4017 has a taper angle greater than or equal to a certain value, and can be manufactured by a simple method, which has the advantage of low manufacturing cost and high yield. The semiconductor layers 4013, 4014, and 4015 have different impurity concentrations. The semiconductor layer 4013 is a channel region, and the semiconductor layer 4014 is a lightly doped drain.
y Doped Drain (LDD) region, and the semiconductor layer 4015 is used as a source region and a drain region. By controlling the amount of impurities in this manner, the resistivity of the semiconductor layer can be controlled. In addition, the electrical connection state between the semiconductor layer and the conductive film 4023 can be brought closer to ohmic connection. In addition, since the transistor has the LDD region, a high electric field is less likely to be applied to the inside of the transistor, and deterioration of the element due to hot carriers can be suppressed. As a method for separately forming semiconductor layers with different amounts of impurities, a method of doping the semiconductor layers with impurities using the gate electrode 4017 as a mask can be used. In the transistor 4002, since the gate electrode 4017 has a taper angle, the concentration of impurities that pass through the gate electrode 4017 and are doped into the semiconductor layer can have a gradient, and an LDD region can be easily formed. can do.

The transistor 4003 has a gate electrode of at least two layers.
017a is a transistor having a shape longer than the upper gate electrode 4017b. In this specification, the shape of the upper gate electrode and the lower gate electrode is referred to as a hat shape.
Since the shape of the gate electrode is hat-shaped, LDD can be realized without adding a photomask.
Regions can be formed. Note that the structure in which the LDD region overlaps with the gate electrode as in the transistor 4003 is particularly referred to as a GOLD structure (Gate Overlapped L).
DD). As a method for making the shape of the gate electrode hat-shaped, the following method may be used.

First, when patterning the gate electrode, the lower layer gate electrode and the upper layer gate electrode are etched by dry etching to form a tapered shape on the side surface. Subsequently, anisotropic etching is performed so that the inclination of the upper gate electrode is almost vertical.
As a result, a gate electrode having a hat-shaped cross section is formed. After that, by doping an impurity element twice, a semiconductor layer 4013 used as a channel region, a semiconductor layer 4014 used as an LDD region, and a semiconductor layer 40 used as a source electrode and a drain electrode are formed.
15 are formed.

An LDD region that overlaps with the gate electrode is called a Lov region, and an LDD region that does not overlap with the gate electrode is called an Loff region. Here, although the Loff region has a high effect of suppressing the off-current value, it has a low effect of alleviating the electric field near the drain and preventing deterioration of the on-current value due to hot carriers. On the other hand, the Lov region relaxes the electric field in the vicinity of the drain and is effective in preventing deterioration of the on-current value, but is less effective in suppressing the off-current value. Therefore, it is preferable to manufacture a transistor having a structure corresponding to required characteristics for each of various circuits. For example, when a display device to which the present invention can be applied is used as a display device, it is preferable to use a transistor having an Loff region as a pixel transistor in order to suppress an off current value. On the other hand, the transistor in the peripheral circuit preferably has an Lov region in order to relax the electric field in the vicinity of the drain and prevent deterioration of the on-current value.

The transistor 4004 has sidewalls 4021 in contact with the side surfaces of the gate electrode 4017 .
is a transistor having By having the sidewalls 4021, the regions overlapping with the sidewalls 4021 can be used as LDD regions.

Transistor 4005 is LDD by doping the semiconductor layer using a mask.
This is a transistor in which a (Loff) region is formed. By doing so, the LDD region can be reliably formed, and the off current value of the transistor can be reduced.

Transistor 4006 is LDD by doping the semiconductor layer using a mask.
(Lov) is a transistor in which a region is formed. By doing so, the LDD region can be reliably formed, the electric field in the vicinity of the drain of the transistor can be relaxed, and deterioration of the on-current value can be reduced.

Next, an example of a method for manufacturing a transistor included in a display device according to the present invention is described with reference to FIGS.

Note that the structure and manufacturing method of the transistor included in the display device according to the present invention are not limited to those shown in FIGS. 48A and 48B, and various structures and manufacturing methods can be used.

In this embodiment mode, a substrate 4011, an insulating film 4012, and semiconductor layers 4013 and 4014 are used.
, 4015, the insulating film 4016, the insulating film 4018, and the insulating film 4019 can be oxidized or nitrided by performing oxidation or nitridation treatment using plasma treatment. Thus, by oxidizing or nitriding a semiconductor layer or an insulating film using plasma treatment, the surface of the semiconductor layer or the insulating film is modified, and compared with an insulating film formed by a CVD method or a sputtering method. A denser insulating film can be formed. Therefore, it is possible to suppress defects such as pinholes and improve the characteristics of the display device.

First, the surface of the substrate 4011 is washed with hydrofluoric acid (HF), alkali or pure water. The substrate 4011 is a glass substrate such as barium borosilicate glass or aluminoborosilicate glass.
A quartz substrate, a ceramic substrate, a metal substrate including stainless steel, or the like can be used. In addition, substrates made of plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), and flexible synthetic resins such as acrylic are also available. It is also possible to use Note that the case where a glass substrate is used as the substrate 4011 is shown here.

Here, the surface of the substrate 4011 is oxidized or nitrided by plasma treatment, and the substrate 4011 is
An oxide film or nitride film may be formed on the surface of (FIG. 48(B)). An insulating film such as an oxide film or a nitride film formed by performing plasma treatment on the surface is hereinafter also referred to as a plasma-treated insulating film. Note that in FIG. 48B, the insulating film 4031 is the plasma-treated insulating film. In general, when a semiconductor element such as a thin film transistor is provided on a substrate such as glass or plastic, impurity elements such as alkali metals such as Na or alkaline earth metals contained in the glass or plastic are mixed into the semiconductor element. This may affect the characteristics of the semiconductor device. However, by nitriding the surface of the substrate made of glass, plastic, or the like, it is possible to prevent impurity elements such as Na contained in the substrate, such as alkali metals or alkaline earth metals, from entering the semiconductor element.

When the surface is oxidized by plasma treatment, it should be performed in an oxygen atmosphere (for example, oxygen (O ₂
) and a rare gas (including at least one of He, Ne, Ar, Kr, and Xe), or an atmosphere of oxygen and hydrogen (H ₂ ) and a rare gas, or an atmosphere of dinitrogen monoxide and a rare gas )
plasma treatment. On the other hand, when the semiconductor layer is nitrided by plasma treatment, the nitrogen atmosphere (for example, nitrogen (N ₂ ) and rare gas (including at least one of He, Ne, Ar, Kr, and Xe) atmosphere, or Plasma treatment is performed in a nitrogen-hydrogen-rare gas atmosphere, or _NH3 and a rare-gas atmosphere). As the rare gas, for example, Ar or a mixed gas of Ar and Kr can be used. Therefore, the plasma-treated insulating film contains a rare gas (including at least one of He, Ne, Ar, Kr, and Xe) used for plasma treatment. For example, when Ar is used, the plasma-treated insulating film contains Ar.

Further, the plasma treatment has an electron density of 1×10 ¹¹ cm ⁻³ in the above gas atmosphere.
1×10 ¹³ cm ⁻³ or more, and the plasma electron temperature is 0.5 eV or more and 1.5 eV
It is preferred to work with: This is because the electron density of the plasma is high and the electron temperature in the vicinity of the object to be processed is low, so that the object to be processed can be prevented from being damaged by the plasma. In addition, since the electron density of the plasma is as high as 1×10 ¹¹ cm ⁻³ or more,
An oxide or nitride film formed by oxidizing or nitriding an object to be irradiated using plasma processing has superior uniformity in film thickness, etc., compared to films formed by CVD, sputtering, or the like.
Moreover, a dense film can be formed. Alternatively, since the plasma electron temperature is as low as 1 eV or less, the oxidation or nitridation treatment can be performed at a lower temperature than in the conventional plasma treatment or thermal oxidation method. For example, even if the plasma treatment is performed at a temperature 100 degrees or more lower than the strain point temperature of the glass substrate, the oxidation or nitridation treatment can be sufficiently performed. Note that a high frequency such as a microwave (2.45 GHz) can be used as a frequency for forming plasma. Unless otherwise specified, the plasma treatment is performed under the above conditions.

Note that FIG. 48B shows the case where the plasma-treated insulating film is formed by plasma-treating the surface of the substrate 4011; Including the case where it is not formed.

Although FIGS. 48C to 48G do not show the plasma-treated insulating film formed by plasma-treating the surface of the object to be processed, in this embodiment, the substrate 40
11. The case where the insulating film 4012, the semiconductor layers 4013, 4014, 4015, the insulating film 4016, the insulating film 4018, or the insulating film 4019 has a plasma-treated insulating film formed by plasma treatment is also included.

Next, known means (sputtering method, LPCVD method, plasma CVD method, etc.) are formed on the substrate 4011 .
is used to form an insulating film 4012 (FIG. 48(C)). As the insulating film 4012, silicon oxide (SiOx) or silicon oxynitride (SiOxNy) (x>y) can be used.

Here, a plasma-treated insulating film may be formed on the surface of the insulating film 4012 by subjecting the surface of the insulating film 4012 to plasma treatment and oxidizing or nitriding the insulating film 4012 . By oxidizing the surface of the insulating film 4012, the surface of the insulating film 4012 can be modified and a dense film with few defects such as pinholes can be obtained. Further, by oxidizing the surface of the insulating film 4012, a plasma-treated insulating film with a low N atom content can be formed. Layer interface properties are improved. In addition, the plasma processing insulating film is made of rare gas (He, Ne, Ar,
including at least one of Kr and Xe). Note that the plasma treatment can be similarly performed under the conditions described above.

Next, island-shaped semiconductor layers 4013 and 4014 are formed over the insulating film 4012 (FIG. 48D).
). The island-shaped semiconductor layers 4013 and 4014 are formed on the insulating film 4012 by a known method (sputtering method, LPCVD method, plasma CVD method, etc.) using a material containing silicon (Si) as a main component (
It can be provided by forming an amorphous semiconductor layer using, for example, SixGe1-x, etc., crystallizing the amorphous semiconductor layer, and selectively etching the semiconductor layer. note that,
Crystallization of the amorphous semiconductor layer may be performed by laser crystallization, thermal crystallization using RTA or furnace annealing, thermal crystallization using a metal element that promotes crystallization, or a combination of these methods. can be carried out by the known crystallization method of Here, the end portions of the island-shaped semiconductor layers are provided in a shape close to a right angle (θ=85 to 100°). Alternatively, the semiconductor layer 4014 to be the low-concentration drain region may be formed by doping impurities using a mask.

Here, the surfaces of the semiconductor layers 4013 and 4014 are subjected to plasma treatment, and the semiconductor layers 4013 and 4014 are
A plasma-treated insulating film may be formed on the surfaces of the semiconductor layers 4013 and 4014 by oxidizing or nitriding the surface of 4014 . For example, Si as the semiconductor layers 4013 and 4014
is used, silicon oxide (SiOx) or silicon nitride (SiN
x) is formed. Alternatively, after the semiconductor layers 4013 and 4014 are oxidized by plasma treatment, they may be nitrided by performing plasma treatment again. In this case, silicon oxide (SiOx) is formed in contact with the semiconductor layers 4013 and 4014, and silicon nitride oxide (SiNxOy) (x>y) is formed on the surface of the silicon oxide. Note that when the semiconductor layer is oxidized by plasma treatment, an oxygen atmosphere (for example, oxygen (O ₂ ) and a rare gas (He, Ne, A
The plasma treatment is performed in an atmosphere containing at least one of r, Kr, and Xe), an atmosphere of oxygen and hydrogen (H ₂ ) and a rare gas, or an atmosphere of dinitrogen monoxide and a rare gas). On the other hand, when the semiconductor layer is nitrided by plasma treatment, the nitrogen atmosphere (for example, nitrogen (N ₂ ) and rare gas (including at least one of He, Ne, Ar, Kr, and Xe) atmosphere, or Plasma treatment is performed in a nitrogen, hydrogen, and rare gas atmosphere or NH3 and a rare gas atmosphere). For example, Ar can be used as the rare gas. Alternatively, a mixed gas of Ar and Kr may be used. Therefore, the plasma-treated insulating film is made of the rare gas (He, Ne,
, including at least one of Ar, Kr, and Xe). For example, when Ar is used, the plasma-treated insulating film contains Ar.

Next, an insulating film 4016 is formed (FIG. 48(E)). The insulating film 4016 is formed of silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy) (x>y), oxynitride using known means (sputtering method, LPCVD method, plasma CVD method, etc.). Silicon (SiNx
It can be provided with a single-layer structure of an insulating film containing oxygen or nitrogen, such as Oy) (x>y), or a stacked-layer structure thereof. Note that when the surfaces of the semiconductor layers 4013 and 4014 are plasma-treated to form plasma-treated insulating films on the surfaces of the semiconductor layers 4013 and 4014,
A plasma-treated insulating film can also be used as the insulating film 4016 .

Here, a plasma-treated insulating film may be formed on the surface of the insulating film 4016 by subjecting the surface of the insulating film 4016 to plasma treatment and oxidizing or nitriding the surface of the insulating film 4016 .
Note that the plasma-treated insulating film is composed of rare gases (He, Ne, Ar, Kr,
including at least one of Xe). Also, the plasma treatment can be similarly performed under the conditions described above.

Alternatively, the insulating film 4016 may be nitrided by performing plasma treatment again in a nitrogen atmosphere after oxidizing the insulating film 4016 by once performing plasma treatment in an oxygen atmosphere. By performing plasma treatment on the insulating film 4016 and oxidizing or nitriding the surface of the insulating film 4016 in this manner, the surface of the insulating film 4016 can be modified and a dense film can be formed. An insulating film obtained by plasma treatment is denser and has fewer defects such as pinholes than an insulating film formed by a CVD method or a sputtering method, so that the characteristics of a thin film transistor can be improved.

Next, a gate electrode 4017 is formed (FIG. 48(F)). The gate electrode 4017 can be formed using known means (sputtering method, LPCVD method, plasma CVD method, etc.).

In the transistor 4001, by performing impurity doping after forming the gate electrode 4017, the semiconductor layer 4015 used as the source region and the drain region can be formed.

In the transistor 4002, by performing impurity doping after forming the gate electrode 4017, a semiconductor layer 4014 used as an LDD region, a semiconductor layer 4013, and a semiconductor layer 4015 used as source and drain regions can be formed.

In the transistor 4003, impurity doping is performed after gate electrodes 4017a and 4017b are formed, so that 4014 used as an LDD region and a semiconductor layer 4013 are formed.
, a semiconductor layer 4015 that is used as source and drain regions can be formed.

In the transistor 4004, sidewalls 4021 are formed on the sides of the gate electrode 4017.
4014 used as an LDD region by performing impurity doping after forming 4014;
A semiconductor layer 4013 and a semiconductor layer 4015 used as source and drain regions can be formed.

The sidewalls 4021 can be made of silicon oxide (SiOx) or silicon nitride (SiNx). As a method for forming the sidewalls 4021 on the side surfaces of the gate electrode 4017, for example, after forming the gate electrode 4017, silicon oxide (SiOx) or silicon nitride (SiNx) is formed into a film by a known method, and then an anisotropic film is formed. Silicon oxide (
SiOx) or a method of etching a silicon nitride (SiNx) film can be used. By doing so, only the side surfaces of the gate electrode 4017 are covered with silicon oxide (SiOx) or silicon nitride (S).
iNx) film can be left, the sidewall 402 is formed on the side surface of the gate electrode 4017 .
1 can be formed.

In the transistor 4005, after forming a mask 4022 to cover the gate electrode 4017, impurity doping is performed to form a 40 region used as an LDD (Loff) region.
14, a semiconductor layer 4013, and a semiconductor layer 4015 used as source and drain regions.
can be formed.

In the transistor 4006, by performing impurity doping after forming the gate electrode 4017, 4014 used as an LDD (Lov) region, a semiconductor layer 4013, and a semiconductor layer 4015 used as a source region and a drain region can be formed. can.

Next, an insulating film 4018 is formed (FIG. 48(G)). The insulating film 4018 is formed of silicon oxide (SiOx) or silicon nitride (SiNx) by known means (sputtering method, plasma CVD method, etc.).
, Silicon oxynitride (SiOxNy) (x>y), Silicon oxynitride (SiNxOy) (x>y)
A single-layer structure of an insulating film containing oxygen or nitrogen such as DLC (diamond-like carbon) or a film containing carbon such as DLC (diamond-like carbon), or a laminated structure thereof can be provided.

Here, a plasma-treated insulating film may be formed on the surface of the insulating film 4018 by subjecting the surface of the insulating film 4018 to plasma treatment and oxidizing or nitriding the surface of the insulating film 4018 .
Note that the plasma-treated insulating film is composed of rare gases (He, Ne, Ar, Kr,
including at least one of Xe). Also, the plasma treatment can be similarly performed under the conditions described above.

Next, an insulating film 4019 is formed (FIG. 48A). The insulating film 4019 is formed of silicon oxide (SiOx) or silicon nitride (SiNx) by known means (sputtering method, plasma CVD method, etc.).
, Silicon oxynitride (SiOxNy) (x>y), Silicon oxynitride (SiNxOy) (x>y)
In addition to insulating films containing oxygen or nitrogen such as DLC (diamond-like carbon) and films containing carbon such as DLC, epoxy, polyimide, polyamide, polyvinylphenol, benzocyclobutene, acrylic, etc. A single-layer structure of an organic material or a siloxane resin, or a laminated structure of these can be provided. Note that the siloxane resin corresponds to a resin containing a Si—O—Si bond. Siloxane has a skeletal structure composed of bonds of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aryl group) is used. A fluoro group can also be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as substituents. In addition, the plasma processing insulating film contains a rare gas (including at least one of He, Ne, Ar, Kr, and Xe) used for plasma processing. Ar is contained in the film.

When an organic material such as polyimide, polyamide, polyvinylphenol, benzocyclobutene, acrylic, or the like, or a siloxane resin is used as the insulating film 4019, the surface of the insulating film 4019 is oxidized or nitrided by plasma treatment, thereby reducing the thickness of the insulating film. surface can be modified. By modifying the surface, the strength of the insulating film 4019 is improved, and it is possible to reduce physical damage such as cracking during opening formation and film reduction during etching. In addition, by modifying the surface of the insulating film 4019, adhesion to the conductive film 4023 is improved when the conductive film 4023 is formed over the insulating film 4019. FIG. For example, when a siloxane resin is used for the insulating film 4019 and nitridation is performed by plasma treatment, the surface of the siloxane resin is nitrided to form a plasma-treated insulating film containing nitrogen or a rare gas, which increases physical strength. improves.

Next, an insulating film 4 is formed to form a conductive film 4023 electrically connected to the semiconductor layer 4015 .
019 , contact holes are formed in the insulating films 4018 and 4016 . The shape of the contact hole may be tapered.
023 coverage can be improved.

FIG. 49 shows a cross-sectional structure of a bottom-gate transistor and a cross-sectional structure of a capacitor.

A first insulating film (insulating film 4102 ) is formed over the entire surface of the substrate 4101 . The first insulating film has a function of preventing impurities from the substrate side from affecting the semiconductor layer and changing the characteristics of the transistor. That is, the first insulating film functions as a base film. Therefore, a highly reliable transistor can be manufactured. Note that as the first insulating film, a single layer such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy), or a lamination thereof can be used.

A first conductive layer (a conductive layer 4103 and a conductive layer 4104) is formed over the first insulating film. The conductive layer 4103 includes a portion functioning as the gate electrode of the transistor 4120 .
The conductive layer 4104 includes a portion functioning as the first electrode of the capacitor 4121 . As the first conductive layer, Ti, Mo, Ta, Cr, W, Al, Nd, Cu, Ag, Au, P
t, Si, Zn, Fe, Ba, Ge, etc., or alloys thereof can be used. Alternatively, lamination of these elements (including alloys) can be used.

A second insulating film (insulating film 4122) is formed to cover at least the first conductive layer. The second insulating film functions as a gate insulating film. Note that as the second insulating film, a single layer such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy), or a lamination thereof can be used.

Note that it is desirable to use a silicon oxide film as the second insulating film in a portion in contact with the semiconductor layer. This is because the trap level at the interface between the semiconductor layer and the second insulating film is reduced.

Moreover, when the second insulating film is in contact with Mo, it is desirable to use a silicon oxide film as the second insulating film in the portion in contact with Mo. This is because the silicon oxide film does not oxidize Mo.

A semiconductor layer is formed on part of a portion of the second insulating film that overlaps with the first conductive layer by a photolithography method, an inkjet method, a printing method, or the like. A portion of the semiconductor layer extends to a portion of the second insulating film that is not formed to overlap with the first conductive layer. The semiconductor layer has a channel formation region (channel formation region 4110
), LDD regions (LDD regions 4108 and 4109), and impurity regions (impurity regions 4105, 4106 and 4107). Note that the channel formation region 4110 functions as a channel formation region of the transistor 4120 . LDD region 4108 and LDD region 4109 function as LDD regions of transistor 4120 . Note that the LDD regions 4108 and 4109 are not necessarily required. Impurity region 4105 includes a portion functioning as one of the source and drain regions of transistor 4120 . Impurity region 4106 includes a portion that functions as the other of the source and drain regions of transistor 4120 . Impurity region 4107 includes a portion functioning as a second electrode of capacitor 4121 .

A third insulating film (insulating film 4111) is formed on the entire surface. A part of the third insulating film has
Contact holes are selectively formed. The insulating film 4111 functions as an interlayer film. As the third insulating film, an inorganic material (silicon oxide, silicon nitride, silicon oxynitride, etc.) or a low dielectric constant organic compound material (photosensitive or non-photosensitive organic resin material) is used.
etc. can be used. Alternatively, materials containing siloxane can be used. Note that siloxane is a material having a skeletal structure composed of a bond between silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (e.g. alkyl group, aryl group)
is used. Alternatively, a fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as substituents.

A second conductive layer (a conductive layer 4112) is formed over the third insulating film. Conductive layer 4112
is connected to the other of the source region and the drain region of the transistor 4120 through a contact hole formed in the third insulating film. Therefore, the conductive layer 4112 includes a portion that functions as the other of the source and drain electrodes of the transistor 4120 . note that,
Ti, Mo, Ta, Cr, W, Al, Nd, Cu, Ag, Au,
Pt, Si, Zn, Fe, Ba, Ge, etc., or alloys thereof can be used. Alternatively, lamination of these elements (including alloys) can be used.

Note that various insulating films or various conductive films may be formed in a step after the formation of the second conductive layer.

Next, structures of a transistor and a capacitor in the case of using an amorphous silicon (a-Si:H) film for a semiconductor layer of the transistor will be described.

FIG. 50 shows a cross-sectional structure of a top-gate transistor and a cross-sectional structure of a capacitor.

A first insulating film (insulating film 4202 ) is formed over the entire surface of the substrate 4201 . The first insulating film has a function of preventing impurities from the substrate side from affecting the semiconductor layer and changing the properties of the transistor. That is, the first insulating film functions as a base film. Therefore, a highly reliable transistor can be manufactured. Note that as the first insulating film, a single layer such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy), or a lamination thereof can be used.

Note that it is not always necessary to form the first insulating film. In this case, the number of steps can be reduced. It is possible to reduce manufacturing costs. Since the structure can be simplified, the yield can be improved.

A first conductive layer (a conductive layer 4203, a conductive layer 4204, and a conductive layer 4205) is formed over the first insulating film.
) is formed. The conductive layer 4203 includes a portion that functions as one of the source and drain electrodes of the transistor 4220 . The conductive layer 4204 is the transistor 422
It includes a portion that functions as the other electrode of the zero source and drain electrodes. Conductive layer 420
5 includes a portion functioning as the first electrode of the capacitor 4221 . As the first conductive layer, Ti, Mo, Ta, Cr, W, Al, Nd, Cu, Ag, Au, Pt, Si, Z
n, Fe, Ba, Ge, etc., or alloys thereof can be used. Alternatively, lamination of these elements (including alloys) can be used.

First semiconductor layers (semiconductor layers 4206 and 4207 ) are formed over the conductive layers 4203 and 4204 . The semiconductor layer 4206 includes portions that function as electrodes for one of the source and drain regions. The semiconductor layer 4207 includes portions that function as electrodes of the other of the source and drain regions. Silicon or the like containing phosphorus or the like can be used as the first semiconductor layer.

A second semiconductor layer (semiconductor layer 4208) is formed between the conductive layers 4203 and 4204 and over the first insulating film. Part of the semiconductor layer 4208 extends over the conductive layers 4203 and 4204 . Semiconductor layer 4208 includes a portion that functions as a channel region of transistor 4220 . As the second semiconductor layer,
A non-crystalline semiconductor layer such as amorphous silicon (a-Si:H), a semiconductor layer such as microcrystalline semiconductor (μ-Si:H), or the like can be used.

A second insulating film (insulating film 4) is formed to cover at least the semiconductor layer 4208 and the conductive layer 4205.
209 and an insulating film 4210) are formed. The second insulating film functions as a gate insulating film. Note that as the second insulating film, a single layer such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy), or a lamination thereof can be used.

Note that it is desirable to use a silicon oxide film as the second insulating film in contact with the second semiconductor layer. This is because the trap level at the interface between the second semiconductor layer and the second insulating film is reduced.

Moreover, when the second insulating film is in contact with Mo, it is desirable to use a silicon oxide film as the second insulating film in the portion in contact with Mo. This is because the silicon oxide film does not oxidize Mo.

A second conductive layer (a conductive layer 4211 and a conductive layer 4212) is formed over the second insulating film. The conductive layer 4211 includes a portion functioning as the gate electrode of the transistor 4220 .
The conductive layer 4212 functions as a second electrode of the capacitor 4221 or a wiring. Note that the second conductive layer includes Ti, Mo, Ta, Cr, W, Al, Nd, Cu, Ag, A
u, Pt, Si, Zn, Fe, Ba, Ge, etc., or alloys thereof can be used. Alternatively, lamination of these elements (including alloys) can be used.

Note that various insulating films or various conductive films may be formed in a step after the formation of the second conductive layer.

FIG. 51 shows a cross-sectional structure of an inverted staggered (bottom-gate) transistor and a cross-sectional structure of a capacitor. In particular, the transistor shown in FIG. 51 has a structure called a channel-etch type.

A first insulating film (insulating film 4302 ) is formed over the entire surface of the substrate 4301 . The first insulating film has a function of preventing impurities from the substrate side from affecting the semiconductor layer and changing the properties of the transistor. That is, the first insulating film functions as a base film. Therefore, a highly reliable transistor can be manufactured. Note that as the first insulating film, a single layer such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy), or a lamination thereof can be used.

Note that it is not always necessary to form the first insulating film. In this case, the number of steps can be reduced. It is possible to reduce manufacturing costs. Since the structure can be simplified, the yield can be improved.

A first conductive layer (a conductive layer 4303 and a conductive layer 4304) is formed over the first insulating film. Conductive layer 4303 includes a portion that functions as the gate electrode of transistor 4320 .
The conductive layer 4304 includes a portion functioning as the first electrode of the capacitor 4321 . The first conductive layer includes Ti, Mo, TB, Cr, W, Bl, Nd, Cu, Bg, Bu, P
t, NA—Si, Zn, Fe, Ba, Ge, etc., or alloys thereof can be used. Alternatively, lamination of these elements (including alloys) can be used.

A second insulating film (insulating film 4302) is formed to cover at least the first conductive layer. The second insulating film functions as a gate insulating film. Note that as the second insulating film, a single layer such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy), or a lamination thereof can be used.

Note that it is desirable to use a silicon oxide film as the second insulating film in a portion in contact with the semiconductor layer. This is because the trap level at the interface between the semiconductor layer and the second insulating film is reduced.

Moreover, when the second insulating film is in contact with Mo, it is desirable to use a silicon oxide film as the second insulating film in the portion in contact with Mo. This is because the silicon oxide film does not oxidize Mo.

A first semiconductor layer (semiconductor layer 43) is formed on a portion of the second insulating film overlapping with the first conductive layer by a photolithography method, an inkjet method, a printing method, or the like.
06) are formed. A portion of the semiconductor layer 4306 extends to a portion of the second insulating film which is not formed to overlap with the first conductive layer. The semiconductor layer 4306 is
A portion that functions as a channel region of the transistor 4320 is included. Note that the semiconductor layer 430
As 6, an amorphous semiconductor layer such as amorphous silicon (A-Si:H) or a semiconductor layer such as microcrystalline semiconductor (μ-Si:H) can be used.

A second semiconductor layer (a semiconductor layer 4307 and a semiconductor layer 4308) is partially formed on the first semiconductor layer.
is formed. The semiconductor layer 4307 includes a portion that functions as an electrode for one of the source and drain regions. The semiconductor layer 4308 includes portions that function as electrodes for the other of the source and drain regions. Silicon containing phosphorus or the like can be used as the second conductor layer.

A second conductive layer (a conductive layer 4309 and a conductive layer 431 is formed over the second semiconductor layer and the second insulating film).
0 and a conductive layer 4311) are formed. Conductive layer 4309 includes portions that function as one of the source and drain electrodes of transistor 4320 . Conductive layer 4310 includes portions that function as the other of the source and drain electrodes of transistor 4320 . Conductive layer 431
2 includes a portion functioning as the second electrode of the capacitor 4321 . As the second conductive layer, Ti, Mo, Ta, Cr, W, Al, Nd, Cu, Ag, Au, Pt, Si, Z
n, Fe, Ba, Ge, etc., or alloys thereof can be used. Alternatively, lamination of these elements (including alloys) can be used.

Note that various insulating films or various conductive films may be formed in a step after the formation of the second conductive layer.

Here, an example of a process characterized by a channel-etched transistor is described. The same mask can be used to form the first semiconductor layer and the second semiconductor layer. in particular,
The first semiconductor layer and the second semiconductor layer are deposited continuously. Then, the first semiconductor layer and the second semiconductor layer are formed using the same mask.

Another example of a process characterized by a channel-etched transistor will be described. A channel region of a transistor can be formed without using a new mask. in particular,
After the second conductive layer is formed, portions of the second semiconductor layer are removed using the second conductive layer as a mask. Alternatively, part of the second semiconductor layer is removed using the same mask as the second conductive layer. The first semiconductor layer formed under the removed second semiconductor layer becomes the channel region of the transistor.

FIG. 52 shows a cross-sectional structure of an inverted staggered (bottom-gate) transistor and a cross-sectional structure of a capacitor. In particular, the transistor shown in FIG. 52 has a structure called a channel protection type (channel stop type).

A first insulating film (insulating film 4402 ) is formed over the entire surface of the substrate 4401 . The first insulating film has a function of preventing impurities from the substrate side from affecting the semiconductor layer and changing the properties of the transistor. That is, the first insulating film functions as a base film. Therefore, a highly reliable transistor can be manufactured. Note that as the first insulating film, a single layer such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy), or a lamination thereof can be used.

Note that it is not always necessary to form the first insulating film. In this case, the number of steps can be reduced. It is possible to reduce manufacturing costs. Since the structure can be simplified, the yield can be improved.

A first conductive layer (a conductive layer 4403 and a conductive layer 4404) is formed over the first insulating film. Conductive layer 4403 includes a portion that functions as the gate electrode of transistor 4420 .
The conductive layer 4404 includes a portion functioning as the first electrode of the capacitor 4421 . As the first conductive layer, Ti, Mo, Ta, Cr, W, Al, Nd, Cu, Ag, Au, P
t, Si, Zn, Fe, Ba, Ge, etc., or alloys thereof can be used. Alternatively, lamination of these elements (including alloys) can be used.

A second insulating film (insulating film 4402) is formed to cover at least the first conductive layer. The second insulating film functions as a gate insulating film. Note that as the second insulating film, a single layer such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy), or a lamination thereof can be used.

Note that it is desirable to use a silicon oxide film as the second insulating film in a portion in contact with the semiconductor layer. This is because the trap level at the interface between the semiconductor layer and the second insulating film is reduced.

Moreover, when the second insulating film is in contact with Mo, it is desirable to use a silicon oxide film as the second insulating film in the portion in contact with Mo. This is because the silicon oxide film does not oxidize Mo.

A first semiconductor layer (semiconductor layer 44) is formed on a portion of the second insulating film overlapping with the first conductive layer by a photolithography method, an inkjet method, a printing method, or the like.
06) are formed. A portion of the semiconductor layer 4406 extends to a portion of the second insulating film which is not formed to overlap with the first conductive layer. The semiconductor layer 4406 is
A portion that functions as a channel region of transistor 4420 is included. Note that the semiconductor layer 440
As 6, an amorphous semiconductor layer such as amorphous silicon (C—Si:H) or a semiconductor layer such as microcrystalline semiconductor (μ-Si:H) can be used.

A third insulating film (insulating film 4412) is formed over part of the first semiconductor layer. The insulating film 4412 has a function of preventing the channel region of the transistor 4420 from being removed by etching. That is, the insulating film 4412 functions as a channel protection film (channel stop film). Note that as the third insulating film, a single layer such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film (SiOxNy), or a lamination thereof can be used.

A second semiconductor layer (semiconductor layer 440
7 and a semiconductor layer 4408) are formed. The semiconductor layer 4407 includes a portion that functions as an electrode for one of the source and drain regions. The semiconductor layer 4408 includes portions that function as electrodes for the other of the source and drain regions. Silicon containing phosphorus or the like can be used as the second conductor layer.

A second conductive layer (a conductive layer 4409, a conductive layer 4410, and a conductive layer 441) is formed over the second semiconductor layer.
1) is formed. Conductive layer 4409 includes portions that function as one of the source and drain electrodes of transistor 4420 . Conductive layer 4410 includes portions that function as the other of the source and drain electrodes of transistor 4420 . The conductive layer 4411 is the capacitive element 44
21 includes a portion that functions as a second electrode. As the second conductive layer, Ti, Mo
, Ta, Cr, W, Al, Nd, Cu, Ag, Au, Pt, Si, Zn, Fe, Ba, G
e, etc., or alloys thereof can be used. Alternatively, lamination of these elements (including alloys) can be used.

Note that various insulating films or various conductive films may be formed in a step after the formation of the second conductive layer.

Here, an example of a process characterized by a channel-protective transistor is described. The same mask can be used to form the first semiconductor layer, the second semiconductor layer, and the second conductive layer.
At the same time, a channel region can be formed. Specifically, a first semiconductor layer is formed,
Next, a third insulating film (channel protection film, channel stop film) is formed using a mask,
Next, a second semiconductor layer and a second conductive layer are continuously formed. Then, after the second conductive layer is deposited, the first semiconductor layer, the second semiconductor layer and the second conductive layer are formed using the same mask. However, since the first semiconductor layer under the third insulating film is protected by the third insulating film, it is not removed by etching. This portion (the portion of the first semiconductor layer over which the third insulating film is formed) becomes the channel region.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each figure of this embodiment is applied or combined with the content (may be part of) described in the figures of other embodiments and examples. , or can be freely replaced. Furthermore, in the drawings of this embodiment, more drawings can be formed by combining parts of other embodiments and examples with respect to each part.

In this embodiment, the contents (or part of them) described in other embodiments and examples are
Example of implementation, example of slight modification, example of partial change, example of improvement, example of detailed description, example of application, example of related parts etc. Therefore, the contents described in other embodiments and examples can be freely applied to, combined with, or replaced with this embodiment.

(Embodiment 12)
In this embodiment, an example of an electronic device according to the present invention will be described.

FIG. 53 shows one form of a display panel module in which a display panel 4501 and a circuit board 4502 are combined.

As shown in FIG. 53, a display panel 4501 includes a pixel portion 4503 and a scanning line driver circuit 4504.
and a signal line driver circuit 4505 . For example, a control circuit 4506 and a signal dividing circuit 4507 are formed on the circuit board 4502 . Note that the display panel 450
1 and the circuit board 4502 are connected by a connection wiring 4508 . FPC or the like can be used for the connection wiring 4508 .

In the display panel 4501, a pixel portion and some peripheral driver circuits (a driver circuit with a low operating frequency among the plurality of driver circuits) are formed integrally over a substrate using transistors, and other peripheral driver circuits (a plurality of driver circuits) are formed over the substrate. (driving circuit with high operating frequency) may be formed on an IC chip, and the IC chip may be mounted on the display panel 3410 by COG (Chip On Glass). Alternatively, the IC chip may be connected to the glass substrate using TAB (Tape Auto Bonding) or a printed circuit board. Alternatively, all peripheral driving circuits may be formed on an IC chip, and the IC chip may be mounted on the display panel by COG or the like.

Note that the pixel described in the above embodiment mode is used for the pixel portion. The present invention can improve the viewing angle. In addition, cost reduction can be achieved by using a transistor of the same conductivity type as a transistor constituting a pixel portion or using an amorphous semiconductor for a semiconductor layer of the transistor.

Such a display module can complete a television receiver. Figure 54 shows
1 is a block diagram showing the main configuration of a television receiver; FIG. A tuner 4601 receives a video signal and an audio signal. A video signal is generated by a video signal amplifier circuit 4602, a video signal processing circuit 4603 that converts the signal output therefrom into color signals corresponding to red, green, and blue, and the video signal is converted to the input specifications of the drive circuit. Processed by control circuit 4506 for conversion.
The control circuit 4506 outputs signals to the scanning line side and the signal line side, respectively. In the case of digital driving, a signal dividing circuit 4507 is provided on the signal line side, and m input digital signals (
(m is a positive integer) may be divided and supplied.

Among the signals received by the tuner 4601, the audio signal is sent to the audio signal amplifier circuit 4604, and its output is supplied to the speaker 4606 via the audio signal processing circuit 4605. The control circuit 4607 receives control information on the reception station (reception frequency) and volume from the input section 4608 and sends signals to the tuner 4601 and the audio signal processing circuit 4605 .

FIG. 55 (see FIG. 55 (
A). In FIG. 55(A), a display screen 4702 housed in a housing 4701 is
It is formed by a display panel module. Note that a speaker 4703 and an operation switch 4704
etc. may be provided as appropriate.

FIG. 55(B) shows a television receiver in which only the display can be carried wirelessly.
A battery and a signal receiver are incorporated in the housing 4712, and the display portion 4713 or the speaker portion 4717 is driven by the battery. The battery can be repeatedly charged with a charger 4710 . The charger 4710 can send and receive video signals and can send the video signals to the display's signal receiver. The housing 4712 is controlled by operation keys 4716 . Alternatively, the device shown in FIG. 55(B) may be a video/audio two-way communication device capable of transmitting signals from housing 4712 to charger 4710 by operating operation keys 4716 . Alternatively, by operating the operation key 4716, a signal is sent from the housing 4712 to the charger 4710, and the signal that can be sent by the charger 4710 is received by the other electronic device, thereby controlling communication of the other electronic device. It may even be a universal remote control, which is possible. The invention can be applied to the display portion 4713 .

FIG. 56A shows a module in which a display panel 4801 and a printed wiring board 4802 are combined. A display panel 4801 includes a pixel portion 4803 provided with a plurality of pixels,
It has a first scanning line driver circuit 4804, a second scanning line driver circuit 4805, and a signal line driver circuit 4806 that supplies video signals to selected pixels.

A controller 4807 and a central processing unit (CPU) 480 are mounted on the printed wiring board 4802 .
8, memory 4809, power supply circuit 4810, audio processing circuit 4811 and transmission/reception circuit 4812
etc. is provided. The printed wiring board 4802 and the display panel 4801 are connected by a flexible wiring board (FPC) 4813 . Flexible printed circuit board (FPC)
The 4813 is provided with a holding capacitor, a buffer circuit, etc. to prevent the generation of noise in the power supply voltage or signal,
Also, it may be configured to prevent an increase in signal rise time. Note that the controller 4807
, an audio processing circuit 4811, a memory 4809, a central processing unit (CPU) 4808, a power supply circuit 4810, etc. are integrated into the display panel 480 using a COG (Chip On Glass) method.
1 can also be implemented. The COG method allows the scale of the printed wiring board 4802 to be reduced.

Various control signals are input/output via an interface (I/F) section 4814 provided on the printed wiring board 4802 . An antenna port 4815 for transmitting and receiving signals to and from the antenna is provided on the printed wiring board 4802 .

FIG. 56(B) shows a block diagram of the module shown in FIG. 56(A). This module includes VRAM 4816, DRAM 4817 and flash memory 48 as memory 4809.
18 are included. Image data to be displayed on the panel is stored in the VRAM 4816 in the DR
Image data or audio data is stored in the AM4817, and various programs are stored in the flash memory.

A power supply circuit 4810 includes a display panel 4801, a controller 4807, a central processing unit (CP
U) supplies power to operate 4808, audio processing circuit 4811, memory 4809, and transmission/reception circuit 4812; However, depending on the specifications of the panel, the power supply circuit 4810 may be provided with a current source.

A central processing unit (CPU) 4808 includes a control signal generating circuit 4820, a decoder 4821, a register 4822, an arithmetic circuit 4823, a RAM 4824, and a central processing unit (CPU) 4808.
has an interface (I/F) unit 4819 for interface (I/
F) Various signals input to the central processing unit (CPU) 4808 via the unit 4819 are temporarily held in a register 4822 and then input to an arithmetic circuit 4823, a decoder 4821, and the like. The arithmetic circuit 4823 performs arithmetic operations based on the input signals and designates locations to which various commands are to be sent. On the other hand, the signal input to the decoder 4821 is decoded and the control signal generation circuit 4
820. Based on the input signal, the control signal generation circuit 4820 generates a signal containing various instructions, and outputs it to a location specified in the arithmetic circuit 4823, specifically the memory 480.
9. Send to transmission/reception circuit 4812, audio processing circuit 4811, controller 4807, and the like.

The memory 4809, transmission/reception circuit 4812, audio processing circuit 4811, and controller 4807 operate according to the received instructions. The operation will be briefly described below.

A signal input from the input means 4825 is sent to a central processing unit (CPU) 4808 mounted on the printed wiring board 4802 via an interface (I/F) section 4814 .
The control signal generation circuit 4820 is connected to the input means 4 such as a pointing device or keyboard.
825, the image data stored in the VRAM 4816 is converted into a predetermined format and sent to the controller 4807. FIG.

The controller 4807 performs data processing on the signal including the image data sent from the central processing unit (CPU) 4808 according to the specifications of the panel, and supplies the processed signal to the display panel 4801 . The controller 4807 generates an Hsync signal, a Vsync signal, a clock signal CLK, an alternating current voltage (AC Cont), generating a switching signal L/R;
It is supplied to the display panel 4801 .

In the transmitting/receiving circuit 4812, signals transmitted and received as radio waves in the antenna 4828 are processed.
Controlled Oscillator), LPF (Low Pass Filt
er), couplers, and baluns. Of the signals transmitted and received by the transmitting/receiving circuit 4812 , a signal containing audio information is sent to the audio processing circuit 4811 according to a command from the central processing unit (CPU) 4808 .

A signal containing audio information sent according to an instruction from the central processing unit (CPU) 4808 is demodulated into an audio signal in an audio processing circuit 4811 and sent to a speaker 4827 . The audio signal sent from the microphone 4826 is modulated in the audio processing circuit 4811 and sent to the transmission/reception circuit 4812 according to the command from the central processing unit (CPU) 4808 .

A controller 4807, a central processing unit (CPU) 4808, a power supply circuit 4810, an audio processing circuit 4811, and a memory 4809 can be mounted as the package of this embodiment.

Of course, the present embodiment is not limited to television receivers, and can be used for a variety of applications, particularly as large-area display media such as monitors for personal computers, information display boards at railway stations and airports, and advertising display boards on the street. can be applied.

Next, a configuration example of the mobile phone according to the present invention will be described with reference to FIG.

A display panel 4901 is detachably incorporated in a housing 4930 . housing 493
0 can be changed in shape or size as appropriate according to the size of the display panel 4901 . A housing 4930 to which a display panel 4901 is fixed is fitted into a printed circuit board 4931 to be assembled as a module.

The display panel 4901 is connected to the printed circuit board 4931 via the FPC 4913 . A printed circuit board 4931 includes a speaker 4932 , a microphone 4933 , and a transmission/reception circuit 49 .
34, a signal processing circuit 4935 including a CPU and a controller is formed. Combining such a module with the input means 4936 and the battery 4937, the housing 493
Store in 9. A pixel portion of the display panel 4901 is arranged so as to be visible through an opening window formed in a housing 4939 .

In the display panel 4901, a pixel portion and some peripheral driver circuits (driver circuits with low operating frequencies among the plurality of driver circuits) are integrally formed on a substrate using transistors. A driver circuit having a high operating frequency among circuits) may be formed over an IC chip, and the IC chip may be mounted on the display panel 4901 by COG (Chip On Glass). Alternatively, the IC chip may be connected to the glass substrate using TAB (Tape Auto Bonding) or a printed circuit board. By adopting such a structure, the power consumption of the display device can be reduced, and the operating time of the mobile phone can be extended with one charge. It is possible to reduce the cost of the mobile phone.

The mobile phone shown in FIG. 57 has a function of displaying various information (still images, moving images, text images, etc.). It has a function of displaying a calendar, date or time on the display. It has a function of operating or editing information displayed on the display unit. It has a function to control processing by various software (programs). It has a wireless communication function. It has the function of communicating with other mobile phones, fixed-line phones, or voice communication devices using wireless communication functions. It has a function to connect to various computer networks using a wireless communication function. It has a function of transmitting or receiving various data using a wireless communication function. It has a function of operating a vibrator in response to incoming calls, data reception, or alarms. It has the function of generating sound in response to incoming calls, data reception, or alarms. Note that the functions of the mobile phone shown in FIG. 57 are not limited to this,
It can have various functions.

The mobile phone shown in FIG. 58 includes a main body (A) 5001 equipped with operation switches 5004, a microphone 5005, and the like, a display panel (A) 5008, and a display panel (B) 5009.
, and a main body (B) 5002 provided with a speaker 5006 and the like are connected with a hinge 5010 so as to be openable and closable. The display panel (A) 5008 and the display panel (B) 5009 are housed in the housing 5003 of the main body (B) 5002 together with the circuit board 5007 . Display panel (A
) 5008 and the pixel portion of the display panel (B) 5009 are arranged so as to be visible through an opening window formed in the housing 5003 .

Specifications such as the number of pixels of the display panel (A) 5008 and the display panel (B) 5009 can be appropriately set according to the functions of the mobile phone 5000 . For example, the display panel (A) 5
008 as the main screen and the display panel (B) 5009 as the sub-screen.

The mobile phone according to this embodiment can be transformed into various aspects according to its functions or uses. For example, an imaging device may be incorporated in the hinge 5010 to form a mobile phone with a camera. Operation switches 5004, display panel (A) 5008, display panel (B) 500
9 can be housed in one housing, the above effects can be obtained. Similar effects can be obtained by applying the configuration of this embodiment to an information display terminal having a plurality of display units.

The mobile phone shown in FIG. 58 has a function of displaying various information (still images, moving images, text images, etc.). It has a function of displaying a calendar, date or time on the display. It has a function of operating or editing information displayed on the display unit. It has a function to control processing by various software (programs). It has a wireless communication function. It has the function of communicating with other mobile phones, fixed-line phones, or voice communication devices using wireless communication functions. It has a function to connect to various computer networks using a wireless communication function. It has a function of transmitting or receiving various data using a wireless communication function. It has a function of operating a vibrator in response to incoming calls, data reception, or alarms. It has the function of generating sound in response to incoming calls, data reception, or alarms. Note that the functions of the mobile phone shown in FIG. 58 are not limited to this,
It can have various functions.

The present invention can be applied to various electronic devices. Specifically, it can be applied to a display portion of an electronic device. Examples of such electronic devices include video cameras, digital cameras, goggle-type displays, navigation systems, sound reproduction devices (car audio, audio components, etc.), computers, game devices, personal digital assistants (mobile computers, mobile phones, portable games, etc.). machine or e-book), image playback device equipped with a recording medium (specifically D
a device equipped with a display capable of reproducing recording media such as digital versatile discs (DVDs) and displaying images thereof).

FIG. 59A shows a display including a housing 5111, a support base 5112, a display portion 5113, and the like. The display shown in FIG. 59A has a function of displaying various information (still image, moving image, text image, etc.) on the display portion. Note that the function of the display illustrated in FIG. 59A is not limited to this, and can have various functions.

FIG. 59B shows a camera including a main body 5121, a display portion 5122, an image receiving portion 5123, operation keys 5124, an external connection port 5125, a shutter button 5126, and the like. Figure 59 (B
) has a function of taking a still image. It has a function to shoot movies. It has a function to automatically correct captured images (still images and movies). It has a function to save captured images in a recording medium (external or internal to a digital camera). It has a function to display the captured image on the display unit. Note that the functions of the camera shown in FIG. 59B are not limited to this, and can have various functions.

FIG. 59C shows a computer including a main body 5131, a housing 5132, a display portion 5133, a keyboard 5134, an external connection port 5135, a pointing device 5136, and the like. The computer shown in FIG. 59(C) stores various information (still images, moving images, text images, etc.)
is displayed on the display unit. It has a function to control processing by various software (programs). It has a communication function such as wireless communication or wired communication. It has the ability to connect to various computer networks using communication functions. It has a function of transmitting or receiving various data using a communication function. Note that the functions of the computer shown in FIG. 59C are not limited to this, and can have various functions.

FIG. 59D shows a mobile computer including a main body 5141, a display portion 5142, a switch 5143, operation keys 5144, an infrared port 5145, and the like. The mobile computer shown in FIG. 59D has a function of displaying various information (still image, moving image, text image, etc.) on the display portion. The display unit has a touch panel function. The display unit has a function of displaying a calendar, date, time, or the like. It has a function to control processing by various software (programs). It has a wireless communication function. It has a function to connect to various computer networks using a wireless communication function. It has a function of transmitting or receiving various data using a wireless communication function. Note that the functions of the mobile computer shown in FIG. 59D are not limited to this, and can have various functions.

FIG. 59(E) shows a portable image reproducing apparatus (for example, a DVD reproducing apparatus) equipped with a recording medium.
DVD, etc.) reading unit 5155, operation keys 5156, speaker unit 5157, and the like. The display portion A5153 can mainly display image information, and the display portion B5154 can mainly display character information.

FIG. 59F shows a goggle-type display including a main body 5161, a display portion 5162, earphones 5163, and a support portion 5164. FIG. The goggle-type display shown in FIG. 59F has a function of displaying an image (a still image, a moving image, a text image, etc.) obtained from the outside on the display portion. Note that the function of the goggle-type display shown in FIG. 59F is not limited to this, and can have various functions.

FIG. 59G shows a portable game machine including a housing 5171, a display portion 5172, and a speaker portion 51.
73, operation keys 5174, a storage medium insertion portion 5175, and the like. A portable game machine using the display device of the present invention for the display portion 5172 can express vivid colors. Figure 59 (G)
2 has a function of reading a program or data recorded in a recording medium and displaying it on a display unit. It has a function to perform wireless communication with other portable game machines and share information. Note that the functions of the portable game machine shown in FIG. 59(G) are not limited to this, and can have various functions.

FIG. 59H shows a digital camera with a television receiving function, which includes a main body 5181 and a display portion 518.
2. Operation keys 5183, speaker 5184, shutter button 5185, image receiving unit 518
6, including antenna 5187 and the like. The digital camera with a television receiver shown in FIG. 59(H) has a function of taking a still image. It has a function to shoot movies. It has a function to automatically correct the captured image. It has a function to acquire various information from the antenna. It has a function to save captured images or information obtained from the antenna. It has a function of displaying a captured image or information obtained from an antenna on the display unit. Note that the functions of the digital camera with television receiver shown in FIG. 59(H) are not limited to this, and can have various functions.

As shown in FIGS. 59A to 59E, the electronic equipment according to the present invention is characterized by having a display section for displaying some information. The electronic device according to the present invention can reduce the frequency of circuit operation by storing duplicated data in the memory, so that power consumption is low and battery operation can be performed for a long time. be.
Next, application examples of the display device according to the present invention will be described.

FIG. 60 shows an example in which the display device according to the present invention is integrated with a building. Figure 60
shows a building including a housing 5200, a display panel 5201, a speaker portion 5202, and the like. Note that 5203 is a remote controller for operating the display panel 5201 .

The pixel described in the above embodiment mode is used for the display panel 5201 . According to the present invention, a display panel with excellent viewing angle characteristics and high display quality can be obtained. Further, cost reduction can be achieved by using a transistor of the same conductivity type as a transistor constituting a pixel portion or using an amorphous semiconductor for a semiconductor layer of the transistor.

Since the display device shown in FIG. 60 is provided integrally with the structure, it can be installed without requiring a large space.

FIG. 61 shows another example in which the display device according to the present invention is integrated with a building. The display panel 5301 is attached integrally with the unit bath 5302, and the bather can view the display panel 5301 while taking a bath. Information can be displayed on the display panel 5301 by being operated by the bather. Therefore, it has a function that can be used as an advertisement or entertainment means.

The pixel described in the above embodiment mode is used for the display panel 5301 . According to the present invention, a display panel with excellent viewing angle characteristics and high display quality can be obtained. Further, cost reduction can be achieved by using a transistor of the same conductivity type as a transistor constituting a pixel portion or using an amorphous semiconductor for a semiconductor layer of the transistor.

It should be noted that the display device according to the present invention can be integrally provided not only on the side wall of the unit bus 5302 shown in FIG. 61 but also in various places. For example, it may be provided integrally with a part of the mirror surface or the bathtub itself. Further, the shape of the display device may be adapted to the mirror surface or the shape of the bathtub.

FIG. 62 shows another example in which the display device according to the present invention is integrated with a building.
In FIG. 62, the display panel 5402 is curved according to the curved surface of the columnar body 5401 . Here, the columnar body 5401 will be described as a utility pole.

A display panel 5402 shown in FIG. 62 is provided at a position higher than the human viewpoint. Information can be provided to an unspecified number of viewers through the display panel 5402 by installing the display panel 5402 on a building such as a utility pole that repeatedly stands outdoors. Therefore, it is suitable to use the display panel as an advertisement. In addition, since the display panel 5402 can easily display the same image by external control and can instantly switch images, extremely efficient information display and advertising effects can be expected. Also, the display panel 5
It can be said that providing a self-luminous display element in 402 is useful as a display medium with high visibility even at night. In addition, by installing the display panel 5402 on a utility pole, the display panel 5
It is easy to secure the power supply means 402 . In the event of an emergency such as a disaster,
It can also serve as a means of quickly transmitting accurate information to disaster victims.

The pixel described in the above embodiment mode is used for the display panel 5402 . According to the present invention, a display panel with excellent viewing angle characteristics and high display quality can be obtained. Further, cost reduction can be achieved by using a transistor of the same conductivity type as a transistor constituting a pixel portion or using an amorphous semiconductor for a semiconductor layer of the transistor. Alternatively, an organic transistor provided over a film-like substrate may be used.

In this embodiment, a wall, a unit bath, and a building integrated with the display device of the present invention
Although a columnar body is illustrated, it can be provided in various other buildings.

Next, an example in which the display device according to the present invention is integrated with a moving object will be described.

FIG. 63 is a diagram showing an example in which a display device according to the present invention is integrated with an automobile. The display panel 5502 is provided integrally with the vehicle body 5501 of the automobile, and can display the operation of the vehicle body and information input from inside and outside the vehicle body on demand. Also, the display panel 5502 may have a navigation function.

The pixel described in the above embodiment mode is used for the display panel 5502 . According to the present invention, a display panel with excellent viewing angle characteristics and high display quality can be obtained. Further, cost reduction can be achieved by using a transistor of the same conductivity type as a transistor constituting a pixel portion or using an amorphous semiconductor for a semiconductor layer of the transistor.

It should be noted that the display device according to the present invention can be provided not only in the vehicle body 5501 shown in FIG. 63, but also in various places. For example, it may be provided integrally with a glass window, door, steering wheel, shift lever, seat, room mirror, or the like. At this time, the shape of the display panel 5502 may be adapted to the shape of the object to be installed.

FIG. 64 is a diagram showing an example in which a display device according to the present invention is integrated with a train car.

FIG. 64(a) is a diagram showing an example in which a display panel 5602 is provided on the glass of a door 5601 of a train car. Compared to conventional paper advertisements, there is an advantage in that there is no labor cost required when switching advertisements. In addition, since the display panel 5602 can instantaneously switch the image displayed on the display unit in response to a signal from the outside, the image on the display panel can be changed, for example, for each time period when the passenger class of passengers on a train changes. You can switch.
By instantaneously switching images in this way, a more effective advertising effect can be expected.

FIG. 64(b) is a diagram showing an example in which a display panel 5602 is provided on a glass window 5603 and a ceiling 5604 in addition to the glass of the door 5601 of the train car. As described above, the display device according to the present invention can be easily installed in a place where installation was conventionally difficult, so that effective advertising effects can be obtained. In addition, the display device according to the present invention can instantaneously switch images displayed on the display unit in response to a signal from the outside. Advertisement operation and information transmission become possible.

Note that the pixels described in the above embodiment modes are used for the display panel 5602 shown in FIG. According to the present invention, a display panel with excellent viewing angle characteristics and high display quality can be obtained. Further, cost reduction can be achieved by using a transistor of the same conductivity type as a transistor constituting a pixel portion or using an amorphous semiconductor for a semiconductor layer of the transistor.

Moreover, the display device according to the present invention is not limited to the above, and can be provided in various places. For example, a strap, a seat, a handrail, a floor, etc., and the display device according to the present invention may be provided integrally. At this time, the shape of the display panel 5602 may be adapted to the shape of the object to be installed.

FIG. 65 is a diagram showing an example in which the display device according to the present invention is integrated with a passenger airplane.

FIG. 65(a) is a diagram showing the shape during use when a display panel 5702 is provided on the ceiling 5701 above the seat of a passenger airplane. Display panel 5702 includes hinge portion 570
The display panel 5702 is provided integrally with the ceiling 5701 via the hinge 5703, and the passenger can view the display panel 5702 at a desired position by expanding and contracting the hinge portion 5703. FIG. The display panel 5702 can display information by being operated by the passenger. Therefore, it has a function that can be used as an advertisement or entertainment means. Also, as shown in FIG. 65(b), the hinge portion is bent to
By storing it in 1, it is possible to consider safety during takeoff and landing. Note that by lighting the display element of the display panel 5702 in an emergency, the display panel 5702 can be used as an information transmission means and a guide light.

Note that the pixel described in the above embodiment mode is used for the display panel 5702 shown in FIG. According to the present invention, a display panel with excellent viewing angle characteristics and high display quality can be obtained. Further, cost reduction can be achieved by using a transistor of the same conductivity type as a transistor constituting a pixel portion or using an amorphous semiconductor for a semiconductor layer of the transistor.

It should be noted that the display device according to the present invention can be provided integrally with various places in addition to the ceiling 5701 shown in FIG. For example, it may be provided integrally with a seat, a seat table, an armrest, a window, or the like. Also, a large display panel that can be viewed by many people at the same time may be installed on the wall of the fuselage. At this time, the shape of the display panel 5702 may be adapted to the shape of the object to be installed.

In the present embodiment, a train car body, a car body, and an airplane body are exemplified as moving bodies.
, trains (including monorails, railroads, etc.), ships, and the like. Since the display device according to the present invention can instantaneously switch the display of the display panel in the moving object by a signal from the outside, the display device according to the present invention can be installed in the moving object to make the moving object invisible. It can be used for applications such as an advertisement display board for a specific number of customers and an information display board in the event of a disaster.

In the present embodiment, descriptions have been made using various diagrams, but the contents described in each diagram (
may be part of it) shall apply, combine, or
Alternatively, replacement can be freely performed. Furthermore, in the figures described so far, more figures can be configured by combining each part with another part.

Similarly, the content (may be part of) described in each figure of this embodiment is applied or combined with the content (may be part of) described in the figures of other embodiments and examples. , or can be freely replaced. Furthermore, in the drawings of this embodiment, more drawings can be formed by combining parts of other embodiments and examples with respect to each part.

In this embodiment, the contents (or part of them) described in other embodiments and examples are
Example of implementation, example of slight modification, example of partial change, example of improvement, example of detailed description, example of application, example of related parts etc. Therefore, the contents described in other embodiments and examples can be freely applied to, combined with, or replaced with this embodiment.

11 node 30 TFT
3a scanning line 6a data line (signal line)
100 Wiring 111 Switch 112 Switch 113 Switch 114 First resistor 115 Second resistor 116 Signal line 117 Scanning line 118 Common electrode 119 Cs line 121 First liquid crystal element 122 Second liquid crystal element 131 First holding capacitor 132 Second 2 storage capacitor 141 node 142 node 211 first transistor 212 second transistor 213 third transistor 313 third transistor 414 transistor 511 signal line driver circuit 512 scanning line driver circuit 513 pixel portion 514 pixel 614 transistor 800 node 801 Unit 814 Transistor 823 Liquid Crystal Element 833 Holding Capacitor 116a Signal Line 117a Scanning Line 119a Cs Line 1200 Pixel 1219 Potential Supply Line 1300 Signal Line Switching Circuit 1316 Wiring 1319 Wiring 1400 Unit 1401 Inverter 1402 Wiring 1402 Wiring 1403 Wiring 1404 Transistor 1405 Transistor 1406 Transistor 1407 Transistor 1430 Wiring 1601 Third storage capacitor 1701 Third storage capacitor 1801 Third storage capacitor 1802 Node 1803 Node 1804 Transistor 1901 Storage capacitor 1902 Node 900a Sub-pixel 900b Sub-pixel 1000a Sub-pixel 1000b Sub-pixel 1100a Sub-pixel 1100b Sub-pixel

Claims (6)

has a pixel,
The pixels are
a switch;
a first transistor;
a second transistor;
a first liquid crystal element;
a second liquid crystal element;
The first liquid crystal element has a first pixel electrode,
The second liquid crystal element has a second pixel electrode,
one terminal of the switch is always conductive with the first pixel electrode;
the other terminal of the switch is in constant conduction with the source line;
one of the source and the drain of the first transistor is always conductive with the second pixel electrode;
one of the source or drain of the first transistor is always conductive with one of the source or drain of the second transistor;
the other of the source and the drain of the second transistor is always conductive with the first wiring;
ON/OFF of the switch is controlled by a gate line,
the gate line has a region functioning as a gate of the first transistor;
the gate line has a region functioning as a gate of the second transistor;
The potential of the source line is supplied to the first pixel electrode,
The potential of the source line is supplied to the other of the source and the drain of the first transistor,
The potential of the other of the source or the drain of the first transistor is applied to the second pixel electrode based on the magnitude of the on-resistance of the first transistor and the magnitude of the on-resistance of the second transistor. and a potential obtained by dividing the potential difference from the potential of the first wiring,
the ratio of the channel width to the channel length of the first transistor is greater than the ratio of the channel width to the channel length of the second transistor;
the first pixel electrode has translucency,
The transmissive liquid crystal display device, wherein the second pixel electrode is translucent. has a pixel,
The pixels are
a switch;
a first transistor;
a second transistor;
a first liquid crystal element;
a second liquid crystal element;
The first liquid crystal element has a first pixel electrode,
The second liquid crystal element has a second pixel electrode,
one terminal of the switch is always conductive with the first pixel electrode;
the other terminal of the switch is in constant conduction with the source line;
one of the source and the drain of the first transistor is always conductive with the second pixel electrode;
one of the source or drain of the first transistor is always conductive with one of the source or drain of the second transistor;
the other of the source and the drain of the second transistor is always conductive with the first wiring;
ON/OFF of the switch is controlled by a gate line,
the gate line has a region functioning as a gate of the first transistor;
the gate line has a region functioning as a gate of the second transistor;
when the switch is on, the first transistor is on, and the second transistor is on;
The potential of the source line is supplied to the first pixel electrode,
The potential of the source line is supplied to the other of the source and the drain of the first transistor,
Further, the second pixel electrode is provided with the other of the source or the drain of the first transistor based on the magnitude of the on-resistance of the first transistor and the magnitude of the on-resistance of the second transistor. a potential obtained by dividing a potential difference between the potential and the potential of the first wiring is supplied;
the ratio of the channel width to the channel length of the first transistor is greater than the ratio of the channel width to the channel length of the second transistor;
The first pixel electrode has translucency,
The transmissive liquid crystal display device, wherein the second pixel electrode is translucent. In claim 1 or 2,
A conductive layer is provided,
The transmissive liquid crystal display device, wherein the conductive layer has a region functioning as one of the source and drain of the first transistor, and has a region functioning as one of the source and drain of the second transistor. In claim 3,
The transmissive liquid crystal display device, wherein the conductive layer has a region in contact with the second pixel electrode. In any one of claims 1 to 4,
The transmissive liquid crystal display device, wherein the first wiring functions as a potential supply line. An electronic device comprising the transmissive liquid crystal display device according to claim 1 .

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