JP2018049227A - Display device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device having excellent visibility even under strong light.SOLUTION: Between a first substrate and a second substrate, provided are a first display element configured to reflect visible light and a second display element configured to allow the passage of visible light. Under strong light the first display element is operated, and under weak light the second display element is operated, so that it becomes possible to display an image with excellent visibility. On a first surface of the second substrate, provided is a touch sensor, and on a second surface opposite the first surface, provided is an antireflection layer. Thus, it is possible to sufficiently suppress the reflection of external light on the display surface under strong light and further improve the visibility.SELECTED DRAWING: Figure 1

Description

The present invention relates to an object, a method, or a manufacturing method. Or this invention relates to a process, a machine, a manufacture, or a composition (composition of matter). In particular, one embodiment of the present invention relates to a semiconductor device, a light-emitting device, a display device, an electronic device, a lighting device, a driving method thereof, or a manufacturing method thereof. In particular, the present invention relates to a display device (display panel) capable of displaying on a curved surface. Alternatively, the present invention relates to an electronic device, a light-emitting device, a lighting device, or a manufacturing method thereof including a display device capable of displaying on a curved surface.

Note that in this specification and the like, a semiconductor device refers to any device that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, a memory device, or the like is one embodiment of a semiconductor device. In addition, the imaging light emitting device, the display device, the electronic device, the lighting device, and the electronic device may include a semiconductor device.

In recent years, electronic devices such as smartphones and tablet terminals have become widespread, and opportunities for using information communication outdoors have increased. Further, in the field of display devices included in electronic devices, development of low power consumption technology capable of long-time operation with a battery having a limited capacity is competing. For example, Patent Document 1 discloses a liquid crystal display device with low power consumption that holds an image signal for a long time by using a transistor having an oxide semiconductor with low off-state current for a pixel.

As a display device included in an electronic apparatus, a display device in which a reflective liquid crystal display device and a transmissive liquid crystal display device are combined has been proposed. For example, as a liquid crystal display device that takes advantage of the reflective liquid crystal display device and enables use in an environment where ambient illumination light is weak, a part of the incident light is transmitted and the remaining incident light is reflected. A liquid crystal display device using a so-called semi-transmissive reflective film is proposed in Patent Document 2.

JP 2011-141522 A JP 2002-372710 A

In a display device included in an electronic device, a transmissive liquid crystal element using a backlight as a light source, a self-luminous organic EL element, or the like is often used. Although these display elements have good visibility indoors, external light reflection on the display surface is strong under strong light such as outdoors in fine weather, so that the light (display) emitted from the inside of the display device is visible. Sex is reduced.

For this reason, it is preferable to use a reflective display element utilizing reflection of external light under strong light. For example, in a display device using a reflective liquid crystal element, the visibility increases as the external light intensity increases. However, since the display surface of the display device uses a glass substrate or a resin substrate having a reflectance of several percent, the influence of external light reflection on the display is not solved.

In addition, in a conventional liquid crystal display device using a semi-transmissive reflective film, a reflective liquid crystal display element and a transmissive liquid crystal display element are controlled by one transistor. There is a problem that the transmission type liquid crystal display element cannot be controlled independently. There is also a problem that the light from the backlight cannot be used efficiently.

Therefore, an object of one embodiment of the present invention is to provide a display device with favorable visibility even under strong light. Another object is to provide a display element having a function of transmitting visible light and a display device including a display having a function of reflecting visible light. Another object is to provide a display system with low power consumption. Another object is to provide a novel display device. Another object is to provide a new electronic device.

Note that the description of these problems does not disturb the existence of other problems. In one embodiment of the present invention, it is not necessary to solve all of these problems. Problems other than those described above are naturally clarified from the description of the specification and the like, and problems other than the above can be extracted from the description of the specification and the like.

One embodiment of the present invention relates to a display device having a function of emitting visible light, a display device having a function of reflecting visible light, a display device using a display device having a function of emitting visible light and a function of reflecting visible light. . Further, the present invention relates to an electronic device having the display device.

One embodiment of the present invention is a display device including a first substrate, a second substrate, a first display element, a second display element, an input device, and a driver circuit. The first substrate and the second substrate have regions that overlap each other, and the first display element and the second display element include a first surface of the first substrate and a first surface of the second substrate. The first display element has a function of reflecting visible light, the second display element has a function of transmitting visible light, and the first surface of the second substrate An input device is provided between the first display element and the second display element, and an antireflection layer is provided on the second surface facing the first surface of the second substrate. A drive circuit is provided over the first surface of the first substrate, and the input device and the drive circuit are display devices that are electrically connected through flexible wiring.

The first display element and the second display element can be provided in the same pixel unit.

The driver circuit can have a function of driving the first display element, the second display element, and the input device.

The antireflection layer may also be provided on the second surface of the second substrate.

The antireflection layer can be formed of a dielectric layer. Alternatively, the antireflection layer may be formed with an antiglare pattern.

The input device includes a wiring having a first layer provided on the first surface of the second substrate, and a second layer provided in contact with the first layer, The layer is preferably formed of a material having a lower visible light reflectance than the second layer.

It is preferable that a light diffusion plate and a polarizing plate are provided between the first display element and the second display element and the input device.

The first display element and the second display element are each preferably electrically connected to a transistor including a metal oxide in a semiconductor layer where a channel is formed.

In this specification, a module in which a connector, for example, an FPC (Flexible printed circuit) or TCP (Tape Carrier Package) is attached to a display device (display unit), a module in which a printed wiring board is provided at the end of TCP, Alternatively, a module in which an IC (Integrated Circuit) is directly mounted on a substrate over which a display element is formed by a COG (Chip On Glass) method may include a display device.

By using one embodiment of the present invention, a display device with favorable visibility can be provided even under strong light. Alternatively, a display element having a function of emitting visible light and a display device including a display having a function of reflecting visible light can be provided. Alternatively, a display system with low power consumption can be provided. Alternatively, a novel display device can be provided. Alternatively, a novel electronic device can be provided.

Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. It should be noted that the effects other than these are naturally obvious from the description of the specification, drawings, claims, etc., and it is possible to extract the other effects from the descriptions of the specification, drawings, claims, etc. It is.

FIG. 10 illustrates a display device. The figure explaining an antireflection layer. FIG. 10 illustrates a display device. FIG. 10 illustrates a connection example between a driver circuit and an FPC. The figure explaining idling stop drive. The figure explaining a pixel unit. The figure explaining a pixel unit. The figure explaining a pixel unit. 4A and 4B each illustrate a circuit of a display device and a top view of a pixel. FIG. 6 illustrates a circuit of a display device. FIG. 6 illustrates a circuit of a display device. FIG. 6 illustrates a structure of a display device. The figure explaining the structure of a touch sensor. The figure explaining the structure of a touch sensor. FIG. 6 illustrates a structure of a display device. FIG. 6 illustrates a structure of a display device. FIG. 6 illustrates a structure of a display device. The conceptual diagram of a structure of a metal oxide. The figure explaining the measurement result of the XRD spectrum of a sample. The figure explaining the TEM image of a sample, and an electron beam diffraction pattern. The figure explaining the EDX mapping of a sample. 6A and 6B illustrate a transistor. 6A and 6B illustrate a transistor. 6A and 6B illustrate a transistor. FIG. 6 illustrates a structure of a display module. 10A and 10B each illustrate an electronic device. 10A and 10B each illustrate an electronic device. 4A and 4B illustrate a change in gradation after monochrome display of a display device having a liquid crystal layer. The graph which shows the relationship between the specific resistance of a liquid crystal layer, and the dipole moment of the molecule | numerator of a liquid crystal layer.

Embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

Note that in structures of the invention described below, the same portions or portions having similar functions are denoted by the same reference numerals in different drawings, and description thereof is not repeated. In addition, in the case where the same function is indicated, the hatch pattern is the same, and there is a case where no reference numeral is given.

Note that in each drawing described in this specification, the size, the layer thickness, or the region of each component is exaggerated for simplicity in some cases. Therefore, it is not necessarily limited to the scale.

In the present specification and the like, ordinal numbers such as “first” and “second” are used for avoiding confusion between components, and are not limited numerically.

(Embodiment 1)
In this embodiment, a display device of one embodiment of the present invention will be described with reference to drawings.

A display device of one embodiment of the present invention includes a first substrate, a second substrate, a first display element, a second display element, an input device, and a driver circuit.

The first display element has a function of reflecting visible light, and the second display element has a function of transmitting visible light. Therefore, it is possible to perform display with low power consumption and good visibility, such as operating the first display element under strong light and operating the second display element under low light.

The first display element, the second display element, and the input device are provided between the first substrate and the second substrate. An input device is provided on the first surface of the second substrate, and an antireflection layer is provided on the second surface facing the first surface. Therefore, reflection of external light on the display surface can be sufficiently suppressed under strong light, and visibility can be further improved.

FIG. 1A illustrates a display device of one embodiment of the present invention. A display device 10 illustrated in FIG. 1A includes a first substrate 11, a second substrate 12, a layer 20, a driver circuit 30, an FPC 31, and an FPC 32.

As the first substrate 11 and the second substrate 12, for example, glass substrates can be used. Alternatively, a flexible resin substrate may be used. Note that since the display device 10 uses a second display element that transmits visible light, a light-transmitting material is used for the first substrate 11 and the second substrate 12 side.

The antireflection layer 13 is provided on both the first surface and the second surface of the second substrate 12 or on the second surface. The antireflection layer 13 can have a structure shown in FIGS. 2A to 2F, for example.

FIG. 2A illustrates an example in which a light-transmitting dielectric layer 13 a is provided on the second surface of the second substrate 12 that is the upper surface of the display device 10. By providing a multilayer dielectric layer having an appropriate thickness as the dielectric layer 13a, reflected light can be suppressed by the light interference effect. The reflectance of one side of the glass substrate is about 4 to 5%, but it is about 0.05 to 0.5% by providing a translucent dielectric layer 13a on the second surface of the second substrate 12. The reflectance can be suppressed.

Further, as shown in FIG. 2B, by providing a light-transmitting dielectric layer 13b on the first surface of the second substrate 12, the reflectance on the back surface side of the glass substrate can be suppressed. . In this case, the reflectance can be suppressed to about 0.1 to 1.0% on the front and back of the second substrate 12. Therefore, reflection of external light can be suppressed and display visibility can be improved.

Alternatively, as shown in FIG. 2C, an antiglare pattern 13 c formed with fine protrusions may be provided on the second surface of the second substrate 12. Reflected light can be scattered by the anti-glare pattern 13c, and the display by the reflective display element can be easily seen. Further, it is possible to make it difficult to get fingerprints and other dirt. 2C shows an example in which the antiglare pattern 13c is provided by processing the second surface of the second substrate 12, but the antiglare pattern is formed as shown in FIG. 2D. The film 13d may be attached to the second surface of the second substrate 12.

Further, as shown in FIG. 2E, an antiglare pattern 13c and a dielectric layer 13b may be combined. Further, as shown in FIG. 2F, a film 13d on which an antiglare pattern is formed and a dielectric layer 13b may be combined.

A layer 20 is provided between the first substrate 11 and the second substrate 12. The layer 20 will be described with reference to FIG. FIG. 1B corresponds to the cross section at the position X1-X2 shown in FIG. 1, and the thickness direction is enlarged for clarity. The layer 20 includes an element layer 21, a substrate 22, a light diffusing plate 23, a polarizing plate 24 b, an input device 25, and an adhesive layer 26.

The element layer 21 includes an FET layer 21a, an LC1 layer 21b, and an LC2 layer 21c. The FET layer 21a includes a transistor that forms a pixel circuit. The LC1 layer 21b has a first display element. The LC2 layer 21c has a second display element. The first display element and the second display element are electrically connected to the transistor included in the FET layer 21a.

As the first display element, for example, a reflective liquid crystal element can be used. For example, a transmissive liquid crystal element can be used as the second display element. The reflective liquid crystal element has low power consumption and can perform display with high visibility even under sunlight in fine weather. The transmissive liquid crystal element can perform display with high visibility under indoor light or outdoors in cloudy weather.

The substrate 22 has a function of sealing the liquid crystal layer included in the first display element. The substrate 22 may be a glass substrate or a resin substrate such as a film.

The light diffusion plate 23 has a function of diffusing light reflected by the reflective electrode of the liquid crystal element. With this function, a natural color can be generated even with a reflective liquid crystal element. In addition, it is possible to display a white color close to a blank sheet.

As the polarizing plate 24b, for example, a circular polarizing plate can be used. By utilizing the change in the deflection angle caused by the circularly polarizing plate and the liquid crystal, display using reflected light can be performed.

A polarizing plate 24 a is provided on the second surface opposite to the first surface of the first substrate 11. As the polarizing plate 24a, for example, a circular polarizing plate can be used. Display using transmitted light can be performed by utilizing the change in the deflection angle caused by the liquid crystal included in the polarizing plates 24a and 24b and the LC2 layer.

As the input device 25, for example, a capacitive touch sensor can be used. The input device 25 is provided so as to overlap with the display unit, and has a function of converting an operation in which the user touches the display unit into an electric signal and outputting the electric signal.

The input device 25 is provided on the first surface of the second substrate 12 as shown in FIG. Alternatively, it may be provided on the dielectric layer 13b described above. As the capacitive touch sensor, a light-transmitting conductive film can be used as a wiring and an electrode, but it is preferable to use a metal mesh having a lower resistance and applicable to a large display device. In general, metal is a material having a high reflectance, but it can be darkened by performing an oxidation treatment or the like. Therefore, even when the second substrate 12 is provided on the first surface, reflection of external light can be suppressed.

The input device 25 is an external type, and is configured to overlap the first display element and the second display element with an adhesive layer 26 having a light-transmitting property with respect to visible light. Since the input device 25 can be manufactured in a process different from the manufacturing process of the transistor, the first display element, and the second display element, the yield of each element can be improved.

The drive circuit 30 may have a function of controlling the input device 25 in addition to a function as a source driver that supplies image data to the first display element and the second display element. The drive circuit 30 can be provided by mounting an IC chip formed using, for example, a silicon wafer. Alternatively, the driver circuit 30 may be formed using a transistor provided over the first substrate 11.

1A, 1 </ b> B, and 3, a form in which a bare chip is mounted by COG is illustrated as the drive circuit 30, but it may be provided by using TCP or COF (Chip on Film). .

The drive circuit 30 is electrically connected to a circuit for supplying image data via the FPC 31. Further, the input device 25 is electrically connected to the drive circuit 30 via the FPC 32. The FPCs 31 and 32 are flexible substrates on which wirings are formed. For example, the FPCs 31 and 32 can be formed by bonding a polyimide film and a copper wiring.

4A to 4D are diagrams for explaining electrical connection of the driving circuit 30, the FPC 31, and the FPC 32. FIG.

FIG. 4A shows an example in which the drive circuit 30 has a function as a source driver for supplying image data to the first display element and the second display element and a function for controlling the input device 25. At this time, the drive circuit 30 can be electrically connected to the FPC 31 through the wiring 33a. Further, the drive circuit 30 can be electrically connected to the FPC 32 through the wiring 33b.

FIG. 4B shows an example in which the drive circuit 30 is divided into two. Here, the driving circuit 30a has a function as a source driver that supplies image data to the first display element and the second display element. The drive circuit 30b has a function of controlling the input device 25. At this time, the drive circuit 30a can be electrically connected to the FPC 31 through the wiring 33a. In addition, the drive circuit 30b can be electrically connected to the FPC 32 through the wiring 33b.

Note that as illustrated in FIG. 4C, the driver circuit 30a and the driver circuit 30b may be electrically connected through a wiring 33c. As shown in FIG. 4D, the FPC 31 and the FPC 32 may be electrically connected through a wiring 33d. With such a configuration, wiring for supplying a power supply voltage and a signal can be reduced.

As the transistor provided in the FET layer 21a, a transistor having a metal oxide in a channel region (hereinafter referred to as an OS transistor) is preferably used. The OS transistor has an extremely small off-state current and can hold a potential written as image data for a long time. Therefore, so-called idling stop driving is possible in which image display can be maintained without writing new image data in a plurality of frame periods.

In the idling stop driving, the image data written in the pixel can be held for two frames or more. As a result, the frequency of rewriting image data can be reduced, so that power consumption can be reduced.

Since the reflective liquid crystal element that can be used as the first display element does not require a backlight, the power consumption of the pixel portion is equal to the power consumption of the circuit operation. Therefore, it is particularly preferable to idle-stop drive the pixel having the first display element, and the power consumption of the pixel portion can be reduced in proportion to the rewrite frequency.

An example of the idling stop driving described above will be described with reference to FIGS.

FIG. 5A illustrates a circuit diagram of a pixel including the liquid crystal element 35 and the pixel circuit 36. FIG. 5A illustrates the transistor M1, the capacitor Cs _LC, and the liquid crystal element LC connected to the signal line SL and the gate line GL.

FIG. 5B is a timing chart showing waveforms of signals supplied to the signal line SL and the gate line GL in the normal driving mode that is not idling stop driving. In the normal drive mode, it can be operated at a normal frame frequency (for example, 60 Hz).

When each period of successive frames at the frame frequency is T ₁ , T ₂ , and T ₃ , a scanning signal is given to the gate line in each frame period, and an operation of writing the signal line data D ₁ to the pixel is performed. This operation is the same regardless of whether the same data D ₁ is written at T ₁ , T ₂ , T ₃ or different data is written.

FIG. 5C is a timing chart showing waveforms of signals given to the signal line SL and the gate line GL in idling stop driving. In idling stop driving, it can be operated at a low frame frequency (for example, 1 Hz).

In FIG. 5C, a frame period at the frame frequency is represented by T ₁ , a period for writing data therein is represented by T _W , and a period for retaining data is represented by T _RET . Idling stop driving gives the scanning signal to the gate lines in a period T _W, write data D ₁ of the signal line to the pixel, fix the gate line to the low level voltage at time T _RET, the transistor M1 as a non-conductive state It performs an operation of holding temporarily the data D ₁ written to the pixel.

Here, by using the OS transistor as the transistor M1, it is possible for a long time holding the data D ₁ by the lower off-current. 5A to 5C show examples using the liquid crystal element LC, but idling stop driving can be similarly performed using a light emitting element such as an organic EL element.

Note that in the circuit diagram shown in FIG. 5 (A), the liquid crystal element LC is the leak path of the data _{D 1.} Therefore, in order to appropriately perform idling stop driving, the specific resistance of the liquid crystal element LC is preferably set to 1.0 × 10 ¹⁴ Ω · cm or more.

Here, the anisotropy of the dielectric constant of the liquid crystal layer will be described with reference to FIG.

First, image sticking of the display device in the case where two materials having different dielectric anisotropies are used as the material for the liquid crystal layer will be described.

The first display device uses a liquid crystal material (Material 1) having a dielectric anisotropy of 3.85 for the liquid crystal layer, and the second display device has an anisotropic dielectric constant for the liquid crystal layer. A liquid crystal material (Material 2) having a property of 2.2 is used.

In addition, as an evaluation method of burn-in of the display device, a halftone display (White → Half Tone) after white display with respect to a gradation when a halftone is continuously displayed (Half Tone → Half Tone), The gradation deviation between the halftone display after the black display (Black → Half Tone) with respect to the gradation when the halftone is displayed is measured. FIG. 28 shows the result of gradation change after monochrome display. In FIG. 28, the vertical axis represents a change in halftone (gray level), and the horizontal axis represents a time from halftone writing.

From the results shown in FIG. 28, the liquid crystal material having a dielectric anisotropy of 3.85 (Material 1) has a deviation of 7.2 tones between White → Half Tone and Black → Half Tone. Recognize. On the other hand, in the liquid crystal material (Material 2) having an anisotropy of dielectric constant of 2.2, it is understood that there is a shift of 1.4 gradations between White → Half Tone and Black → Half Tone. In FIG. 28, data when a halftone is continuously displayed (Half Tone → Half Tone) of a liquid crystal material (Material 2) having an anisotropy of dielectric constant of 2.2 is an intermediate after white display. The data is displayed almost overlapping with the data of the key display (White → Half Tone).

From the results shown in FIG. 28, it can be seen that the use of a material with low dielectric constant anisotropy for the liquid crystal layer can suppress gradation shift.

Note that the allowable range of the gradation value deviation in the same still image means, for example, a deviation of 0 gradation or more and 3 gradations or less when an image is displayed by controlling the transmittance in 256 steps. If the gradation value shift in the same still image is a gradation value shift between 0 gradation and 3 gradations, it is difficult for the viewer to perceive flicker. As another example, when an image is displayed by controlling the transmittance in 1024 steps, it means a deviation of 0 to 12 gradations. That is, it is preferable that the allowable range of the gradation value shift in the same still image is 1% or more and 1.2% or less of the maximum number of gradations to be displayed.

Next, the dipole moment of the liquid crystal layer will be described with reference to FIG.

The graph shown in FIG. 29 shows the relationship between the dipole moment of a molecule and the specific resistance as an example of a liquid crystal layer having molecules having a dipole moment of 0 to 3 debye.

The vertical axis | shaft of the graph shown in FIG. 29 shows the dipole moment of a molecule | numerator (Dipole moment). In the measurement of the values in FIG. 29, the liquid crystal layer is formed by mixing the base liquid crystal and an additive material added thereto. The dipole moment is the dipole moment of the additive material molecule. The horizontal axis shown in FIG. 29 represents the specific resistance of the liquid crystal layer, that is, the base liquid crystal and the additive material. The mixing ratio of the base liquid crystal and the additive material is mixed so that the additive material is 20% by weight with respect to the entire mixed material. Hereinafter, a mixture of the base liquid crystal and the additive material is referred to as “mixed liquid crystal”. Each point of FIG. 29 shows the relationship between the dipole moment of the molecule of the additive material and the specific resistance of each mixed liquid crystal to which the additive material is added for each type of additive material by changing the type of additive material added to the base liquid crystal. It is a thing.

In FIG. 29, the specific resistance value of the mixed liquid crystal increases as the value of the dipole moment of the molecule of the additive material decreases. In other words, when the dipole moment of the additive material is large, the specific resistance decreases.

From FIG. 29, the mixed liquid crystal having a dipole moment of molecules of the additive material of 3 debyes or less has a specific resistance value of 1.0 × 10 ¹⁴ Ω · cm or more. If the dipole moment of the molecule of the additive material is small, the specific resistance value becomes large. For example, when the molecular structure is symmetric with respect to the center of the molecule, the charge distribution is not biased, so the dipole moment becomes zero. Therefore, as a display device of one embodiment of the present invention, the permanent dipole moment of the additive material molecule is preferably 0 Debye or more and 3 Debye or less, and the specific resistance is 1.0 × 10 ¹⁴ Ω · cm or more. This is preferable.

As a metal oxide used for the above-described transistor, for example, a later-described CAC-OS (Cloud-Aligned Composite-Oxide Semiconductor) can be used.

In particular, an oxide semiconductor having a larger band gap than silicon is preferably used. When a semiconductor material having a wider band gap and lower carrier density than silicon is used, current in an off state of the transistor can be reduced.

In addition, due to the low off-state current, the charge accumulated in the capacitor through the transistor can be held for a long time. By applying such a transistor to a pixel, the driving circuit can be stopped while maintaining the gradation of an image displayed in each display region. As a result, an electronic device with extremely low power consumption can be realized.

In addition, a polycrystalline semiconductor may be used for the above-described pixel or a semiconductor device such as a transistor used in a circuit for driving the pixel. For example, it is preferable to use polycrystalline silicon. Polycrystalline silicon can be formed at a lower temperature than single crystal silicon, and has higher field effect mobility and higher reliability than amorphous silicon. By applying such a polycrystalline semiconductor to a pixel, the aperture ratio of the pixel can be improved. In addition, even when a large number of pixels are included, the gate driver circuit and the source driver circuit can be formed over the same substrate as the pixel, and the number of components included in the electronic device can be reduced.

By using the above structure, a display device that can perform display with high visibility can be provided regardless of the environment of external light. In particular, the display device has an advantage that visibility is good even under strong light and the device can be operated with low power consumption.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 2)
In this embodiment, a display device of one embodiment of the present invention and a method for driving the display device will be described.
The display device of one embodiment of the present invention can include a pixel provided with a first display element that reflects visible light and a pixel provided with a second display element that emits visible light.

The display device has a function of displaying an image using one or both of first light reflected by the first display element and second light transmitted by the second display element. Alternatively, the display device functions to express gradation by controlling the amount of first light reflected by the first display element and the amount of second light emitted by the second display element, respectively. Have

In addition, the display device controls the first pixel that expresses gradation by controlling the amount of reflected light from the first display element, and the gradation by controlling the amount of transmitted light from the second display element. A structure including the second pixel to be expressed is preferable. A plurality of first pixels and second pixels are arranged in a matrix, for example, and constitute a display unit.

In addition, it is preferable that the first pixels and the second pixels are arranged in the display area with the same number and the same pitch. At this time, the adjacent first pixel and second pixel can be collectively referred to as a pixel unit. Thereby, as will be described later, an image displayed with only the plurality of first pixels, an image displayed with only the plurality of second pixels, and both the plurality of first pixels and the plurality of second pixels. Each of the images displayed in can be displayed in the same display area.

As the first display element included in the first pixel, an element that reflects external light for display can be used. Since such an element does not have a light source, power consumption during display can be extremely reduced.

As the first display element, a reflective liquid crystal element can be typically used. Alternatively, as a first display element, in addition to a shutter-type MEMS (Micro Electro Mechanical System) element, an optical interference-type MEMS element, a microcapsule type, an electrophoretic method, an electrowetting method, and an electronic powder fluid (registered trademark) An element to which a method or the like is applied can be used.

As the second display element included in the second pixel, an element which displays light by transmitting light from a light source can be used. As the display element included in the second pixel, a transmissive liquid crystal element that controls the amount of transmitted light can be used. As the light source, for example, a backlight can be used.

The first pixel can include a sub-pixel that exhibits, for example, white (W), or a sub-pixel that exhibits three colors of light, for example, red (R), green (G), and blue (B). . Similarly, the second pixel has a sub-pixel that exhibits, for example, white (W), or a sub-pixel that exhibits light of three colors, for example, red (R), green (G), and blue (B). can do. Note that the subpixels included in each of the first pixel and the second pixel may have four or more colors. As the number of subpixels increases, power consumption can be reduced and color reproducibility can be improved.

According to one embodiment of the present invention, a first mode in which an image is displayed with a first pixel, a second mode in which an image is displayed with a second pixel, and an image is displayed with the first pixel and the second pixel. The third mode can be switched.

The first mode is a mode in which an image is displayed using reflected light from the first display element. The first mode is a driving mode with extremely low power consumption because no light source is required. For example, it is effective when the illuminance of outside light is sufficiently high and the outside light is white light or light in the vicinity thereof. The first mode is a display mode suitable for displaying character information such as books and documents. In addition, since the reflected light is used, it is possible to perform display that is kind to the eyes, and the effect that the eyes are less tired is achieved. Note that the first mode may be referred to as a reflection type display mode because it displays using reflected light.

The second mode is a mode in which an image is displayed using light transmitted by the second display element. Therefore, an extremely vivid display (high contrast and high color reproducibility) can be performed regardless of the illuminance and chromaticity of external light. For example, it is effective when the illuminance of outside light is extremely small, such as at night or in a dark room. Further, when the outside light is dark, the user may feel dazzled when performing bright display. In order to prevent this, it is preferable to perform display with reduced luminance in the second mode. Thereby, in addition to suppressing glare, power consumption can also be reduced. The second mode is a mode suitable for displaying a vivid image or a smooth moving image. Note that the second mode may be referred to as a transmissive display mode (transmission mode) because display is performed using transmitted light.

The third mode is a mode in which display is performed using both reflected light from the first display element and transmitted light from the second display element. Specifically, driving is performed so as to express one color by mixing light emitted by the first pixel and light emitted by the second pixel adjacent to the first pixel. While displaying more vividly than in the first mode, it is possible to suppress power consumption as compared with the second mode. For example, it is effective when the illuminance of outside light is relatively low, such as under room lighting or in the morning or evening hours, or when the chromaticity of outside light is not white.

Note that in this specification and the like, display in which the first display element and the second display element are combined, that is, the third mode can be referred to as a hybrid display mode (HB display mode). Alternatively, the third mode may be referred to as a display mode (TR-Hybrid mode) in which a transmissive display mode and a reflective display mode are combined. A display capable of hybrid display can be referred to as a hybrid display.

Here, the definition of hybrid display and hybrid display will be described.

The hybrid display method is a method of displaying characters or / and images by displaying a plurality of lights in the same pixel or the same sub-pixel. The hybrid display is an aggregate that displays a plurality of lights and displays characters or / and images in the same pixel or the same sub-pixel included in the display unit.

As an example of the hybrid display method, there is a method of displaying the first light and the second light with different display timings in the same pixel or the same sub-pixel. At this time, the first light and the second light having the same color tone (red, green, or blue, or any one of cyan, magenta, or yellow) are simultaneously displayed and displayed in the same pixel or the same sub-pixel. Characters and / or images can be displayed in the part.

Note that in the hybrid display method, a plurality of lights may be displayed not in the same pixel or the same subpixel but in an adjacent pixel or an adjacent subpixel. Displaying the first light and the second light at the same time refers to displaying the first light and the second light for the same period to the extent that the flicker is not sensed by human eyes. If the flicker is not sensed with the sense, the display period of the first light and the display period of the second light may be shifted.

The hybrid display is an aggregate that includes a plurality of display elements in the same pixel or the same sub-pixel, and each of the plurality of display elements displays in the same period.
The hybrid display includes a plurality of display elements and active elements that drive the display elements in the same pixel or the same sub-pixel. Examples of active elements include switches, transistors, and thin film transistors. Since the active element is connected to each of the plurality of display elements, the display of each of the plurality of display elements can be individually controlled.

As a structure of the display device, a structure having a display panel including a first pixel and a second pixel and a control unit can be employed. The control unit generates and outputs a first gradation value to be output to the first pixel and a second gradation value to be output to the second pixel based on image information input from the outside. Here, the image information is information including gradation values corresponding to each pixel unit, and examples thereof include video signals such as video signals.

Note that the control unit may have a function of selecting the display mode described above based on the illuminance of external light or the like.

The first pixel includes a first transistor electrically connected to the first display element, and the second pixel is a second transistor electrically connected to the second display element. It is preferable to have.

At this time, it is preferable that the first transistor and the second transistor are formed on the same surface. At this time, any one of the first display element and the second display element is preferably electrically connected to the first transistor or the second transistor through an opening provided in the insulating layer. . Accordingly, since the first transistor and the second transistor can be manufactured in the same process, the process can be simplified.

In addition, by adopting a structure in which the first display element, the second display element, and each transistor are sandwiched between a pair of substrates, a thin and lightweight display device can be realized.

The second display element using transmitted light can have a structure in which a backlight and a transmissive display element are combined. At this time, by using a light source that emits white light as a backlight and the second display element has a colored layer (color filter), a structure capable of color display can be obtained.

The second display element may have a structure for performing color display by a time gray scale method (also referred to as a field sequential method). At this time, a red (R), green (G), and blue (B) light can be dispersed as a backlight and a light source capable of repeatedly emitting light can be used. That is, color display can be performed by the time gray scale method by interlocking the second display element and the backlight.

At this time, in order to prevent a change in luminance from being perceived as flicker (flicker), it is preferable to increase a cycle (also referred to as a drive frequency or a subframe frequency) for changing the color of light of the backlight. For example, the driving frequency can be 30 Hz to 720 Hz, preferably 60 Hz to 360 Hz, more preferably 60 Hz to 240 Hz, typically 180 Hz.

Hereinafter, more specific examples of one embodiment of the present invention will be described with reference to the drawings.

[Configuration example of display device]
FIG. 6 illustrates a pixel array 40 included in the display device of one embodiment of the present invention. The pixel array 40 has a plurality of pixel units 45 arranged in a matrix. The pixel unit 45 includes a pixel 46 and a pixel 47.

In FIG. 7A, the first pixel 46 has a display element corresponding to white (W), and the second pixel 47 has three colors of red (R), green (G), and blue (B). An example in the case of having a corresponding display element is shown.

The first pixel 46 includes a display element 46W corresponding to white (W). The display element 46W is a first display element that utilizes reflection of external light.

The second pixel 47 includes a display element 32R corresponding to red (R), a display element 32G corresponding to green (G), and a display element 32B corresponding to blue (B). Each of the display elements 32R, 32G, and 32B is a second display element that transmits light from the light source.

[Configuration example of pixel unit]
FIG. 6B is a schematic diagram illustrating a configuration example of the pixel unit 45.

The first pixel 46 includes a display element 46W. The display element 46W is an element that reflects and displays external light. The display element 46W reflects external light and emits white light Wr to the display surface side.

The second pixel 47 includes a display element 47R, a display element 47G, and a display element 47B. The display elements 47R, 47G, and 47B are elements that transmit visible light. The display element 47R emits red light Rt to the display surface side. Similarly, the display element 47G and the display element 47B respectively emit green light Gt or blue light Bt to the display surface side.

Subsequently, a display mode by the pixel unit 45 will be described with reference to FIGS.

[First mode]
FIG. 7A corresponds to a mode (first mode) in which display is performed using only reflected light by driving the first pixel 46. For example, when the illuminance of outside light is sufficiently high, the pixel unit 45 does not drive the second pixel 47 and uses only the light from the first pixel 46, so that the light 55r that is reflected light is emitted. It can be emitted to the display surface side. Thereby, driving with extremely low power consumption can be performed. In addition, display that is kind to the eyes can be performed.

[Second mode]
FIG. 7B corresponds to a mode (second mode) in which display is performed using only transmitted light by driving the second pixels 47. For example, when the illuminance of outside light is extremely small, the pixel unit 45 does not drive the first pixel 46 and mixes only the light from the second pixel 47 (light Rt, light Gt, and light Bt). By doing so, light 55t of a predetermined color can be emitted to the display surface side. Thereby, a vivid display can be performed. Further, by reducing the luminance when the illuminance of outside light is small, it is possible to suppress glare that the user feels and to reduce power consumption.

[Third mode]
FIG. 7C corresponds to a mode (third mode) in which display is performed by driving both the first pixel 46 and the second pixel 47 within the same period. The pixel unit 45 emits light 55tr of a predetermined color in which reflected light and transmitted light are mixed to the display surface side by mixing the light Wr, the light Rt, the light Gt, and the light Bt. be able to.

[Modification]
In the above example, the first pixel 46 has a display element corresponding to white, and the second pixel 47 has a display element corresponding to three colors of red (R), green (G), and blue (B). However, the present invention is not limited to this. Below, the example of a structure different from the above is shown.

FIGS. 8A and 8B show an example in which the first pixel 46 has display elements corresponding to three colors of red (R), green (G), and blue (B). .

The first pixel 46 includes a display element 46R, a display element 46G, and a display element 46B. The display elements 46R, 31G, and 31B are elements that reflect and display external light. The display element 46R reflects external light and emits red light Rr to the display surface side. Similarly, the display element 46G and the display element 46B respectively emit green light Gr or blue light Br to the display surface side.

FIG. 8B corresponds to a mode in which display is performed by driving both the first pixel 46 and the second pixel 47 (third mode). The pixel unit 45 displays light 35tr of a predetermined color in which reflected light and transmitted light are mixed by mixing the six lights of light Rr, light Gr, light Br, light Rt, light Gt, and light Bt. Can be injected to the surface side.

At this time, there are a plurality of combinations of the luminances of each of the six lights, light Rr, light Gr, light Br, light Rt, light Gt, and light Bt, so that the light 55tr becomes light of a predetermined luminance and chromaticity. To do. Therefore, the luminance (gradation) of the light Rr, the light Gr, and the light Br emitted from the first pixel 46 among the combinations of the luminances (gradations) of the six lights that realize the light 55tr having the same luminance and chromaticity. It is preferable to select a combination that yields the largest value. Thereby, power consumption can be reduced without sacrificing color reproducibility.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 3)
Examples of display panels that can be used for the display device of one embodiment of the present invention are described below. The display panel exemplified below is a display panel that includes both a reflective liquid crystal element and a transmissive liquid crystal element, and can display in both a transmissive mode and a reflective mode.

[Configuration example]
FIG. 9A is a block diagram illustrating an example of a structure of the display device 800. The display device 800 includes a plurality of pixels 850 arranged in a matrix in the display portion 801. The display device 800 includes a circuit GD and a circuit SD. The pixel 850 includes a plurality of pixels 850 arranged in the direction R, a plurality of wirings G1, a plurality of wirings G2, a plurality of wirings ANO, and a plurality of wirings CSCOM electrically connected to the circuit GD. The pixel 850 includes a plurality of pixels 850 arranged in the direction C, and a plurality of wirings S1 and a plurality of wirings S2 that are electrically connected to the circuit SD.

Here, for the sake of simplicity, a configuration having one circuit GD and one circuit SD is shown, but the circuit GD and the circuit SD that drive the liquid crystal element and the circuit GD and the circuit SD that drive the light emitting element are separately provided. May be provided.

The pixel 850 includes a reflective liquid crystal element and a transmissive liquid crystal element.

FIG. 9B1 illustrates a configuration example of the electrode 861 included in the pixel 850. The electrode 861 functions as a reflective electrode of a reflective liquid crystal element in the pixel 850. The electrode 861 is provided with an opening 851.

In FIG. 9B1, the transmissive liquid crystal element 860 positioned in a region overlapping with the electrode 861 is illustrated by a broken line. The transmissive liquid crystal element 860 is disposed so as to overlap with the opening 851 of the electrode 861. Accordingly, light transmitted through the transmissive liquid crystal element 860 is emitted to the display surface side through the opening 851.

FIG. 9B1 shows two pixels 850 arranged in the direction C. One electrode 861 has one opening 851. At this time, the transmissive liquid crystal element 860 is driven by a time gray scale method to emit light such as red (R), green (G), and blue (B) dispersed in time through the opening 851. Can be injected.

FIG. 9B2 illustrates an example in which one electrode 861 includes three openings 851. At this time, a transmissive liquid crystal element 860 that transmits different colors is stacked in each opening 851. Thereby, light of different colors is emitted from the transmissive liquid crystal elements 860 to the display surface side through the three openings 851.

If the ratio of the total area of the opening 851 to the total area of the non-opening is too large, the display using the reflective liquid crystal element becomes dark. In addition, if the ratio of the total area of the opening 851 to the total area of the non-opening is too small, the display using the transmissive liquid crystal element 860 becomes dark.

In addition, when the area of the opening 851 provided in the electrode 861 functioning as the reflective electrode is too small, the efficiency of light that can be extracted from the light emitted from the transmissive liquid crystal element 860 is reduced.

The shape of the opening 851 can be, for example, a polygon, a rectangle, an ellipse, a circle, a cross, or the like. Moreover, it is good also as an elongated streak shape, a slit shape, and a checkered shape. Further, the opening 851 may be arranged close to adjacent pixels.

[Circuit configuration example]
FIG. 10 is a circuit diagram illustrating a configuration example of the pixel 850. In FIG. 10, two adjacent pixels 850 are shown.

The pixel 850 includes a switch SW1, a capacitor C1, a liquid crystal element 870, a switch SW2, a switch SW2, a capacitor C2, a liquid crystal element 860, and the like. In addition, a wiring G1, a wiring G2, a wiring CSCOM, a wiring S1, and a wiring S2 are electrically connected to the pixel 850. In FIG. 10, a wiring VCOM1 electrically connected to the liquid crystal element 870 and a wiring VCOM2 electrically connected to the liquid crystal element 860 are illustrated.

FIG. 10 shows an example in which transistors are used for the switch SW1 and the switch SW2.

The switch SW1 has a gate connected to the wiring G1, a source or drain connected to the wiring S1, and the other source or drain connected to one electrode of the capacitor C1 and one electrode of the liquid crystal element 870. Yes. The other electrode of the capacitor C1 is connected to the wiring CSCOM. The other electrode of the liquid crystal element 870 is connected to the wiring VCOM1.

The switch SW2 has a gate connected to the wiring G2, one of the source and the drain connected to the wiring S2, and the other of the source and the drain connected to one electrode of the capacitor C2 and one electrode of the liquid crystal element 860. Yes. The other electrode of the capacitor C2 is connected to the wiring CSCOM. The other electrode of the liquid crystal element 860 is connected to the wiring VCOM2.

A signal for controlling the switch SW1 to be in a conductive state or a non-conductive state can be supplied to the wiring G1. A predetermined potential can be applied to the wiring VCOM1. A signal for controlling the alignment state of the liquid crystal included in the liquid crystal element 870 can be supplied to the wiring S1. A predetermined potential can be applied to the wiring CSCOM.

A signal for controlling the switch SW2 to be in a conductive state or a non-conductive state can be supplied to the wiring G2. A predetermined potential can be applied to the wiring VCOM2. A signal for controlling the alignment state of the liquid crystal included in the liquid crystal element 860 can be supplied to the wiring S2.

For example, in the case of performing reflection mode display, the pixel 850 illustrated in FIG. 10 can be driven by a signal supplied to the wiring G1 and the wiring S1 and can display using optical modulation by the liquid crystal element 870. Further, in the case where display is performed in the transmissive mode, display can be performed by driving with signals given to the wiring G2 and the wiring S2 and using optical modulation by the liquid crystal element 860. In the case of driving in both modes, the driving can be performed by signals given to the wiring G1, the wiring G2, the wiring S1, and the wiring S2.

Note that FIG. 10 illustrates an example in which one pixel 850 includes one liquid crystal element 870 and one liquid crystal element 860. By driving the liquid crystal element 860 by the time gray scale method, when displaying in the transmissive mode or both modes, a single pixel 850 can display full color.

FIG. 11 illustrates an example in which one pixel 850 includes one reflective liquid crystal element 870 and three transmissive liquid crystal elements (a liquid crystal element 860r, a liquid crystal element 860g, and a liquid crystal element 860b). The liquid crystal element 860r, the liquid crystal element 860g, and the liquid crystal element 860b are transmissive liquid crystal elements that transmit red (R), green (G), and blue (B) light, respectively. The pixel 850 shown in FIG. 11 can display in full color with three transmissive liquid crystal elements when displaying in the transmissive mode or both modes.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

[Display panel configuration example]
FIG. 12 is a schematic perspective view of a display panel 510 of one embodiment of the present invention. The display panel 510 has a structure in which a substrate 511 and a substrate 512 are bonded to each other. In FIG. 12, the substrate 512 is indicated by a broken line.

The display panel 510 includes a display portion 514, a circuit 516, a wiring 518, and the like. The substrate 511 is provided with, for example, a circuit 516, a wiring 518, an electrode 524 functioning as a pixel electrode, and the like. FIG. 12 shows an example in which an IC 520 and an FPC 522 are mounted on the display panel 510. Therefore, the structure illustrated in FIG. 12 can also be referred to as a display module including the display panel 510, the IC 520, and the FPC 522.

As the circuit 516, for example, a circuit functioning as a scan line driver circuit can be used.

The wiring 518 has a function of supplying a signal and power to the display portion 514 and the circuit 516. The signal and power are input to the wiring 518 from the outside through the FPC 522 or from the IC 520.

FIG. 12 illustrates an example in which the IC 520 is provided on the substrate 511 by a COG (Chip On Glass) method or the like. As the IC 520, for example, an IC having a function as a scan line driver circuit, a signal line driver circuit, or the like can be used. Note that in the case where the display panel 510 includes a circuit that functions as a scan line driver circuit and a signal line driver circuit, or a circuit that functions as a scan line driver circuit or a signal line driver circuit is provided outside, and the display panel 510 is provided via the FPC 522. In the case of inputting a signal for driving, the IC 520 may be omitted. Further, the IC 520 may be mounted on the FPC 522 by a COF (Chip On Film) method or the like.

FIG. 12 shows an enlarged view of a part of the display unit 514. In the display portion 514, electrodes 524 included in the plurality of display elements are arranged in a matrix. The electrode 524 has a function of reflecting visible light, and functions as a reflective electrode of a liquid crystal element 550 described later.

In addition, as illustrated in FIG. 12, the electrode 524 has an opening 526. Further, the display portion 514 includes a transmissive liquid crystal element 570 closer to the substrate 511 than the electrode 524. Light from the liquid crystal element 570 is emitted to the substrate 512 side through the opening 526 of the electrode 524. The area of the transmission region of the liquid crystal element 570 and the area of the opening 526 may be equal. One of the area of the transmissive region of the liquid crystal element 570 and the area of the opening 526 is larger than the other, which is preferable because a margin for positional deviation is increased.

Further, the input device 130 can be provided over the substrate 512. For example, the input device 130 may have a configuration in which a sheet-like capacitive touch sensor is provided over the display portion 514. Alternatively, a touch sensor may be provided between the substrate 511 and the substrate 512. In the case where a touch sensor is provided between the substrate 511 and the substrate 512, an optical touch sensor using a photoelectric conversion element may be used in addition to the capacitive touch sensor.

FIG. 13 is a diagram illustrating an example of a capacitive touch sensor provided on a substrate, and a part thereof is enlarged. FIG. 14A is a top view of the touch sensor and includes a proximity sensor. FIG. 14B is a cross-sectional view taken along section line X3-X4 in FIG. Note that the substrate 560 provided with the touch sensor corresponds to the second substrate 12 illustrated in FIG.

An insulating film 501B illustrated in FIG. 14B corresponds to the adhesive layer 26 illustrated in FIG. The insulating film 572 includes a region sandwiched between the insulating film 501B and the proximity sensor 575.

A detection element that detects a change in capacitance, illuminance, magnetic force, radio wave, pressure, or the like caused by a nearby object and supplies a signal based on the detected physical quantity can be used for the proximity sensor 575.

For example, a conductive film, a photoelectric conversion element, a magnetic detection element, a piezoelectric element, a resonator, or the like can be used as the detection element.

For example, a detection circuit including a function of supplying a signal that changes based on capacitance parasitic on the conductive film can be used for the proximity sensor 575. A control signal can be supplied to the first electrode, and the potential or current of the second electrode that changes based on the supplied control signal and capacitance can be detected and supplied as a detection signal. Thereby, the finger | toe etc. which adjoin to the electrically conductive film in air | atmosphere can be detected using the change of an electrostatic capacitance.

For example, the first electrode C1 (g) and the second electrode C2 (h) can be used for the proximity sensor 575 (see FIGS. 12 and 13A). Note that the second electrode C2 (h) includes a portion that does not overlap the first electrode C1 (g). G and h are natural numbers of 1 or more.

Specifically, the first electrode C1 (g) electrically connected to the control line CL (g) extending in the row direction (the direction of the arrow indicated by R in the drawing) intersects the row direction. A second electrode C2 (h) electrically connected to the signal line ML (h) extending in the column direction (the direction of the arrow indicated by C in the drawing) can be used for the proximity sensor 575.

For example, a conductive film including a light-transmitting region in a region overlapping with the pixel 410 can be used for the first electrode C1 (g) or the second electrode C2 (h).

For example, a mesh-like conductive film including the opening 576 in a region overlapping with the pixel 410 can be used for the first electrode C1 (g) or the second electrode C2 (h).

The control line CL (g) includes a wiring BR (g, h). The control line CL (g) intersects with the signal line ML (h) in the wiring BR (g, h) (see FIG. 13B).

For example, the stacked film can be used for the first electrode C1 (g), the second electrode C2 (h), the control line CL (g), or the signal line ML (h). Specifically, a stacked film in which the conductive film CL (g) A and the dark color film CL (g) B are stacked so that the conductive film CL (g) A is sandwiched between the dark color film CL (g) B and the pixel 410. Can be used.

For example, a film whose reflectance with respect to visible light is lower than that of the conductive film CL (g) A can be used for the dark film CL (g) B. Thereby, reflection of visible light by the first electrode C1 (g), the second electrode C2 (h), the control line CL (g) or the signal line ML (h) can be weakened. As a result, the display on the display portion 514 can be emphasized, and a favorable display can be performed. In addition, the display device can be thinned. Further, stress generated on the substrate 560 or the like when the display device is bent can be reduced.

For example, a material that can be used for the wiring G1, the wiring G2, the wiring ANO, the wiring CSCOM, and the like can be used for the conductive film CL (g) A.

Further, for example, a film containing copper oxide, a film containing copper chloride or tellurium chloride, or the like can be used for the dark color film CL (g) B. Further, the dark color film CL (g) B is composed of metal fine particles such as Ag particles, Ag fibers, and Cu particles, nanocarbon particles such as carbon nanotubes (CNT) and graphene, or conductive polymers such as PEDOT, polyaniline, and polypyrrole. You may form using.

The proximity sensor 575 includes an insulating film 571 between the wiring BR (g, h) and the signal line ML (h). Thereby, a short circuit between the wiring BR (g, h) and the signal line ML (h) can be prevented.

[Section configuration example]
Specific examples of cross-sectional structures of the display device of one embodiment of the present invention are described with reference to FIGS.

<Cross-section configuration example 1>
First, the display device 100A will be described with reference to FIG.

The display device 100 </ b> A includes a first substrate 103 and a second substrate 104. Between the first substrate 103 and the second substrate 104, the first liquid crystal element 105 and the second substrate 104 are provided. The liquid crystal element 108 is sandwiched.

In addition, the first liquid crystal element 105 includes a first electrode 105PE, a second electrode 105CE, and a first liquid crystal layer 105LC located between the first electrode 105PE and the second electrode 105CE. . The second liquid crystal element 108 includes a third electrode 108PE, a fourth electrode 108CE, and a second liquid crystal layer 108LC located between the third electrode 108PE and the fourth electrode 108CE. .

In addition, an element layer 110 is provided between the first liquid crystal element 105 and the second liquid crystal element 108. In this embodiment mode, a first transistor 111 and a second transistor 112 are formed in the element layer 110.

The first transistor 111 is arranged so as to overlap with the first electrode 105PE, and partly separated from the first electrode 105PE with an insulating film (here, a plurality of insulating films) interposed therebetween. . Note that the first electrode 105PE and the first transistor 111 are electrically connected to each other through the first opening 114 formed in the insulating film and the electrode 116 formed in the first opening 114. Is done. The electrode 116 may be referred to as a connection electrode or a through electrode.

The second transistor 112 is disposed so as to overlap with the third electrode 108PE, and partly separated from the third electrode 108PE with an insulating film (here, a plurality of insulating films) interposed therebetween. The Note that the third electrode 108PE and the second transistor 112 are electrically connected through the second opening 118 formed in the insulating film.

The first liquid crystal element 105 has a function of displaying an image by reflecting light, and the second liquid crystal element 108 has a function of displaying an image by transmitting light. That is, the first liquid crystal element 105 is a reflective liquid crystal element, and the second liquid crystal element 108 is a transmissive liquid crystal element.

A light emitting device 122 is disposed below the second substrate 104 via a polarizing plate 120. The light emitting device 122 has a function as a so-called backlight unit, and includes an edge light 122E, a light guide plate 122G, a light extraction unit 122R, and the like.

In FIG. 15, the light emitted from the edge light 122E is indicated by a dotted arrow. In the light emitting device 122, the light emitted from the edge light 122E passes through the light guide plate 122G, is collected by the light extraction unit 122R, and is emitted to the second liquid crystal element 108 side. That is, the light extraction portion 122R has a function as a so-called lens (also referred to as a microlens).

In addition, the first structural body 124 is provided in the element layer 110 that overlaps the light extraction portion 122R. The first structure 124 has at least a reflective film 124R. The light that has passed through the light extraction portion 122R is further condensed by the reflective film 124R included in the first structure 124, and is emitted to the first substrate 103 side.

The reflective film 124R included in the first structure 124 has a shape such that the inner wall continuously decreases in width from the incident side (substrate 104 side) to the emission side (substrate 103 side). For example, you may have the shape which cut off a part of cone. In particular, it is preferable that the inner wall has a constricted three-dimensional curved surface shape (for example, a trumpet shape). In addition, the inner wall of the reflective film 124R preferably has a shape close to a hyperbola in the surface of a pair of opposed inner walls in a cross section perpendicular to the substrate 104 or the like.

Since the first structure 124 has the shape as described above, light emitted from the light extraction unit 122R and transmitted through the second liquid crystal element 108 is incident on the first structure 124 in an oblique direction. Is reflected by the reflective film 124R of the first structure 124, thereby increasing the luminance (light flux per unit area).

As the opening area on the exit side of the reflective film 124R of the first structure 124 is smaller than the opening area on the incident side, the inclination angle of the side surface of the reflective film 124R (the angle formed between the side surface and the surface of the substrate 103) is increased. The closer to 90 degrees and the higher the reflectivity of the reflective film 124R, the higher the luminance of the light transmitted through the first structure 124 can be.

In addition, the region surrounded by the reflective film 124R of the first structure 124 preferably has a high light transmittance. For example, it is preferable to use a material containing aluminum or silver. In addition, the region preferably has a high refractive index. For example, it is preferable to use a material having an absolute refractive index greater than 1 and 2.5 or less, preferably 1.2 or more and 2.0 or less, and more preferably 1.3 or more and 1.9 or less.

A second structure 126 is provided above the first structure 124 and between the first electrode 105PE and the second electrode 105CE. The second structure 126 has a function of controlling the distance between the first electrode 105PE and the second electrode 105CE. That is, the second structure body 126 has a function as a so-called gap spacer or cell gap spacer.

The second structure 126 preferably transmits visible light. The light condensed by the first structure 124 is emitted to the first substrate 103 side through the second structure 126. In addition, by providing the second structure body 126 above the first structure body 124, the light emitted from the edge light 122 </ b> E has a function of suppressing absorption by the first liquid crystal layer 105 </ b> LC.

Above the first substrate 103, a light diffusion plate 128 and a polarizing plate 132 are provided.

Further, the input device 130 provided over the substrate 560 is attached to the polarizing plate 132 with the adhesive layer 141 interposed therebetween.

<Cross-section configuration example 2>
Next, the display device 100B will be described with reference to FIG. Note that the display device 100B is a modification of the display device 100A described above.

In addition to the structure of the display device 100A described above, the display device 100B includes an insulating layer 134, a coloring layer 136, and an insulating layer 138 between the second electrode 105CE and the substrate 103.

The colored layer 136 has a function as a so-called color filter. The insulating layer 138 has a function of controlling the thickness of the colored layer 136.

For example, as illustrated in FIG. 16, the insulating layer 138 is provided in a portion overlapping with the first liquid crystal element 105 and has an opening in a portion overlapping with the second liquid crystal element 108. Accordingly, the colored layer 136 provided so as to cover the insulating layer 138 can be formed to have a larger thickness in a portion overlapping the second liquid crystal element 108 than in a portion overlapping the first liquid crystal element 105. Accordingly, the thickness of the colored layer 136 positioned on the optical path is different between the first liquid crystal element 105 that is a reflective liquid crystal element and the second liquid crystal element 108 that is a transmissive liquid crystal element. be able to.

In FIG. 16, the liquid crystal layer 108 LC has a configuration in which both ends thereof are surrounded by the resin layer 142. The resin layer 142 includes, for example, a resin and a liquid crystal material included in the liquid crystal layer 108LC. By having the resin layer 142, the adhesiveness between the element layer 110 and the substrate 104 is increased, and the mechanical strength of the display device 100B can be increased.

<Cross-section configuration example 3>
Next, the display device 100C will be described with reference to FIG. Display device 100C is a modification of display device 100A and display device 100B described above.

In the display device 100C, the transistor 111 and the transistor 112 are formed over different insulating surfaces.

More specifically, the transistor 112 is provided over the substrate 104. Further, the transistor 111 and the transistor 112 are positioned so as to sandwich the second liquid crystal element 108.

In addition, the coloring layer 140 is provided between the second liquid crystal element 108 and the first structure body 124. The light emitted from the light extraction portion 122R and transmitted through the second liquid crystal element 108 passes through the colored layer 140, the first structure body 124, and the second structure body 126, and is emitted toward the substrate 103 side.

[About each component]
Below, each component shown above is demonstrated.

〔substrate〕
A substrate having a flat surface can be used for the substrate included in the display panel. For the substrate from which light from the display element is extracted, a material that transmits the light is used. For example, materials such as glass, quartz, ceramic, sapphire, and organic resin can be used.

By using a thin substrate, the display panel can be reduced in weight and thickness. Furthermore, a flexible display panel can be realized by using a flexible substrate.

Further, since the substrate on the side from which light emission is not extracted does not have to be translucent, a metal substrate or the like can be used in addition to the above-described substrates. A metal substrate is preferable because it has high thermal conductivity and can easily conduct heat to the entire substrate, which can suppress a local temperature increase of the display panel. In order to obtain flexibility and bendability, the thickness of the metal substrate is preferably 10 μm to 200 μm, and more preferably 20 μm to 50 μm.

Although there is no limitation in particular as a material which comprises a metal substrate, For example, metals, such as aluminum, copper, nickel, or alloys, such as aluminum alloy or stainless steel, can be used suitably.

Alternatively, a substrate that has been subjected to an insulating process by oxidizing the surface of the metal substrate or forming an insulating film on the surface may be used. For example, the insulating film may be formed by using a coating method such as a spin coating method or a dip method, an electrodeposition method, a vapor deposition method, or a sputtering method, or it is left in an oxygen atmosphere or heated, or an anodic oxidation method. For example, an oxide film may be formed on the surface of the substrate.

Examples of materials having flexibility and transparency to visible light include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resins, polyimide resins, polymethyl methacrylate resins, and polycarbonates. (PC) resin, polyethersulfone (PES) resin, polyamide resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyvinyl chloride resin, polytetrafluoroethylene (PTFE) resin, and the like. In particular, a material having a low thermal expansion coefficient is preferably used. For example, a polyamideimide resin, a polyimide resin, PET, or the like having a thermal expansion coefficient of 30 × 10 ⁻⁶ / K or less can be suitably used. Further, a substrate in which glass fiber is impregnated with an organic resin, or a substrate in which an inorganic filler is mixed with an organic resin to reduce the thermal expansion coefficient can be used. Since a substrate using such a material is light in weight, a display panel using the substrate can be lightweight.

When a fibrous body is included in the material, a high-strength fiber of an organic compound or an inorganic compound is used for the fibrous body. The high-strength fiber specifically refers to a fiber having a high tensile modulus or Young's modulus, and representative examples include polyvinyl alcohol fiber, polyester fiber, polyamide fiber, polyethylene fiber, aramid fiber, Examples include polyparaphenylene benzobisoxazole fibers, glass fibers, and carbon fibers. Examples of the glass fiber include glass fibers using E glass, S glass, D glass, Q glass, and the like. These may be used in the form of a woven fabric or a non-woven fabric, and a structure obtained by impregnating the fiber body with a resin and curing the resin may be used as a flexible substrate. When a structure made of a fibrous body and a resin is used as the flexible substrate, it is preferable because reliability against breakage due to bending or local pressing is improved.

Alternatively, glass, metal, or the like thin enough to have flexibility can be used for the substrate. Alternatively, a composite material in which glass and a resin material are bonded to each other with an adhesive layer may be used.

A hard coat layer (for example, silicon nitride, aluminum oxide) that protects the surface of the display panel from scratches, a layer of a material that can disperse the pressure (for example, aramid resin), etc. on a flexible substrate It may be laminated. In order to suppress a decrease in the lifetime of the display element due to moisture or the like, an insulating film with low water permeability may be stacked over a flexible substrate. For example, an inorganic insulating material such as silicon nitride, silicon oxynitride, silicon nitride oxide, aluminum oxide, or aluminum nitride can be used.

The substrate can be used by stacking a plurality of layers. In particular, when the glass layer is used, the barrier property against water and oxygen can be improved and a highly reliable display panel can be obtained.

[Transistor]
The transistor includes a conductive layer that functions as a gate electrode, a semiconductor layer, a conductive layer that functions as a source electrode, a conductive layer that functions as a drain electrode, and an insulating layer that functions as a gate insulating layer. The above shows the case where a bottom-gate transistor is applied.

Note that there is no particular limitation on the structure of the transistor included in the display device of one embodiment of the present invention. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. Further, a top-gate or bottom-gate transistor structure may be employed. Alternatively, gate electrodes may be provided above and below the channel.

There is no particular limitation on the crystallinity of the semiconductor material used for the transistor, and either an amorphous semiconductor or a semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor partially including a crystal region) is used. May be used. It is preferable to use a crystalline semiconductor because deterioration of transistor characteristics can be suppressed.

As a semiconductor material used for the transistor, a metal oxide having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used. A typical example is an oxide semiconductor containing indium. For example, a CAC-OS described later can be used.

A transistor using an oxide semiconductor with a wider band gap and lower carrier density than silicon can hold charge accumulated in a capacitor connected in series with the transistor for a long time due to its low off-state current. Is possible.

The semiconductor layer is represented by an In-M-Zn-based oxide containing indium, zinc, and M (metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium). It can be a membrane.

In the case where the oxide semiconductor included in the semiconductor layer is an In-M-Zn-based oxide, the atomic ratio of the metal elements of the sputtering target used for forming the In-M-Zn oxide is In ≧ M, Zn It is preferable to satisfy ≧ M. As the atomic ratio of the metal elements of such a sputtering target, In: M: Zn = 1: 1: 1, In: M: Zn = 1: 1: 1.2, In: M: Zn = 3: 1: 2, In: M: Zn = 4: 2: 3, In: M: Zn = 4: 2: 4.1, In: M: Zn = 5: 1: 6, In: M: Zn = 5: 1: 7, In: M: Zn = 5: 1: 8 etc. are preferable. Note that the atomic ratio of the semiconductor layer to be formed includes a variation of plus or minus 40% of the atomic ratio of the metal element contained in the sputtering target.

The bottom-gate transistor described in this embodiment is preferable because the number of manufacturing steps can be reduced. In addition, by using an oxide semiconductor at this time, the wiring under the semiconductor layer can be formed at a temperature lower than that of polycrystalline silicon, and a material having low heat resistance can be used as an electrode material and a substrate material. Can widen the choice of materials. For example, a glass substrate having an extremely large area can be suitably used.

As the semiconductor layer, an oxide semiconductor film with low carrier density is used. For example, the semiconductor layer has a carrier density of 1 × 10 ¹⁷ / cm ³ or less, preferably 1 × 10 ¹⁵ / cm ³ or less, more preferably 1 × 10 ¹³ / cm ³ or less, more preferably 1 × 10 ¹¹ / cm 3. ³ or less, more preferably less than 1 × 10 ¹⁰ / cm ³ , and an oxide semiconductor having a carrier density of 1 × 10 ⁻⁹ / cm ³ or more can be used. Such an oxide semiconductor is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Accordingly, it can be said that the oxide semiconductor has stable characteristics because the impurity concentration is low and the density of defect states is low.

Note that the composition is not limited thereto, and a transistor having an appropriate composition may be used depending on required semiconductor characteristics and electrical characteristics (such as field-effect mobility and threshold voltage) of the transistor. In addition, in order to obtain the required semiconductor characteristics of the transistor, it is preferable that the semiconductor layer have appropriate carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, and the like. .

If an oxide semiconductor included in the semiconductor layer contains silicon or carbon which is one of Group 14 elements, oxygen vacancies increase in the semiconductor layer and the semiconductor layer becomes n-type. Therefore, the concentration of silicon or carbon in the semiconductor layer (concentration obtained by secondary ion mass spectrometry) is 2 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁷ atoms / cm ³ or less.

Further, when alkali metal and alkaline earth metal are combined with an oxide semiconductor, carriers may be generated, which may increase off-state current of the transistor. Therefore, the concentration of alkali metal or alkaline earth metal obtained by secondary ion mass spectrometry in the semiconductor layer is set to 1 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁶ atoms / cm ³ or less.

In addition, when nitrogen is contained in the oxide semiconductor included in the semiconductor layer, electrons serving as carriers are generated, the carrier density is increased, and the oxide semiconductor is likely to be n-type. As a result, a transistor including an oxide semiconductor containing nitrogen is likely to be normally on. For this reason, it is preferable that the nitrogen concentration obtained by secondary ion mass spectrometry in the semiconductor layer is 5 × 10 ¹⁸ atoms / cm ³ or less.

The semiconductor layer may have a non-single crystal structure, for example. The non-single-crystal structure includes, for example, a CAAC-OS (C-Axis Crystalline Oxide Semiconductor Semiconductor having a crystal oriented in the c-axis, or a C-Axis Aligned and A-B-Plane Annealed Crystal Oxide Crystal Structure, Includes a microcrystalline structure or an amorphous structure. In the non-single-crystal structure, the amorphous structure has the highest density of defect states, and the CAAC-OS has the lowest density of defect states.

An oxide semiconductor film having an amorphous structure has, for example, disordered atomic arrangement and no crystal component. Alternatively, an amorphous oxide film has, for example, a completely amorphous structure and does not have a crystal part.

Note that the semiconductor layer may be a mixed film including two or more of an amorphous structure region, a microcrystalline structure region, a polycrystalline structure region, a CAAC-OS region, and a single crystal structure region. Good. For example, the mixed film may have a single-layer structure or a stacked structure including any two or more of the above-described regions.
<Configuration of CAC-OS>
The details of a metal oxide having a CAC structure that can be used for a semiconductor layer of a transistor disclosed in one embodiment of the present invention are described below. Here, as a typical example of a metal oxide having a CAC structure, description will be made using a CAC-OS.

In other words, the CAC-OS refers to a region 101 containing each element as a main component due to the uneven distribution of elements constituting a metal oxide, for example, as in the example formed over the insulating film 106 illustrated in FIG. And regions 102, and each region is mixed and formed or dispersed in a mosaic. That is, it is one structure of a material in which elements constituting the metal oxide are unevenly distributed in a size of 0.5 nm to 10 nm, preferably 0.5 nm to 3 nm, or the vicinity thereof.

The physical characteristics of a region where a specific element is unevenly distributed are determined by the properties of the element. For example, a region in which elements that tend to become insulators are relatively uneven among the elements constituting the metal oxide is a dielectric region. On the other hand, a region in which elements that tend to be conductors are relatively uneven among the elements constituting the metal oxide is a conductor region. In addition, when the conductor region and the dielectric region are mixed in a mosaic, the material functions as a semiconductor.

That is, the metal oxide in one embodiment of the present invention is a kind of matrix composite or metal matrix composite in which materials having different physical characteristics are mixed.

Note that the oxide semiconductor preferably contains at least indium. In particular, it is preferable to contain indium and zinc. In addition to them, element M (M is gallium, aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum. , One or more selected from tungsten, magnesium, or the like.

For example, a CAC-OS in In-Ga-Zn oxide (In-Ga-Zn oxide among CAC-OSs may be referred to as CAC-IGZO in particular) is an indium oxide (hereinafter referred to as InO). _X1 (X1 is greater real than 0) and.), or indium zinc oxide _{(hereinafter, in X2 Zn Y2 O Z2 (} X2, Y2, and Z2 is larger real than 0) and a.), gallium An oxide (hereinafter referred to as GaO _X3 (X3 is a real number greater than 0)) or a gallium zinc oxide (hereinafter referred to as Ga _X4 Zn _Y4 O _Z4 (where X4, Y4, and Z4 are greater than 0)) to.) and the like, the material becomes mosaic by separate into, mosaic _{InO X1} or _in X2 _Zn Y2 _{O Z2,} is a configuration in which uniformly distributed in the film (hereinafter Also referred to as a cloud-like.) A.

That, CAC-OS includes a region _{GaO X3} is the main _component, and In _{X2 Zn} Y2 _{O Z2,} or _{InO X1} is the main component region is a composite oxide semiconductor having a structure that is mixed. Note that in this specification, for example, the first region indicates that the atomic ratio of In to the element M in the first region is larger than the atomic ratio of In to the element M in the second region. It is assumed that the concentration of In is higher than that in the second region.

Note that IGZO is a common name and may refer to one compound of In, Ga, Zn, and O. As a typical example, InGaO ₃ (ZnO) _m1 (m1 is a natural number) or In _{(1 + x0)} Ga _(1-x0) O ₃ (ZnO) _m0 (−1 ≦ x0 ≦ 1, m0 is an arbitrary number) A crystalline compound may be mentioned.

The crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. The CAAC structure is a crystal structure in which a plurality of IGZO nanocrystals have c-axis orientation and are connected without being oriented in the ab plane.

On the other hand, CAC-OS relates to a material structure of an oxide semiconductor. CAC-OS refers to a nanoparticulate region mainly composed of Ga and partly composed of In, in a material configuration containing In, Ga, Zn, and O. Are observed, each of which is randomly dispersed in a mosaic pattern. Therefore, in the CAC-OS, the crystal structure is a secondary element.

Note that the CAC-OS does not include a stacked structure of two or more kinds of films having different compositions. For example, a structure composed of two layers of a film mainly containing In and a film mainly containing Ga is not included.

Incidentally, a region _{GaO X3} is the main _component, and In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component region, in some cases clear boundary can not be observed.

In addition, instead of gallium, aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium are selected. In the case where one or a plurality of types are included, in the CAC-OS, a nanoparticulate region mainly containing the element is observed in part, and a nanoparticulate region mainly containing In is partly observed. Are observed, each of which is randomly dispersed in a mosaic pattern.

<Analysis of CAC-OS>
Subsequently, the results of measurement of an oxide semiconductor film formed on a substrate using various measurement methods will be described.

<< Sample structure and production method >>
In the following, nine samples according to one embodiment of the present invention are described. Each sample is manufactured under different conditions for the substrate temperature and the oxygen gas flow rate when the oxide semiconductor film is formed. Note that the sample has a structure including a substrate and an oxide semiconductor over the substrate.

A method for manufacturing each sample will be described.

First, a glass substrate is used as the substrate. Subsequently, an In—Ga—Zn oxide with a thickness of 100 nm is formed as an oxide semiconductor over the glass substrate with a sputtering apparatus. The deposition conditions are such that the pressure in the chamber is 0.6 Pa and an oxide target (In: Ga: Zn = 4: 2: 4.1 [atomic ratio]) is used as the target. In addition, 2500 W AC power is supplied to the oxide target installed in the sputtering apparatus.

Note that the substrate temperature was set to a temperature at which the substrate was not intentionally heated (hereinafter also referred to as room temperature or RT), 130 ° C., or 170 ° C. as a condition for forming the oxide film. In addition, nine samples are manufactured by setting the flow rate ratio of oxygen gas to the mixed gas of Ar and oxygen (hereinafter also referred to as oxygen gas flow rate ratio) to 10%, 30%, or 100%.

≪Analysis by X-ray diffraction≫
In this item, the results of X-ray diffraction (XRD) measurement on nine samples will be described. Note that Bruker D8 ADVANCE was used as the XRD apparatus. The condition is that the scanning range is 15 deg. In θ / 2θ scanning by the out-of-plane method. To 50 deg. , The step width is 0.02 deg. The scanning speed is 3.0 deg. / Min.

FIG. 19 shows the results of measuring the XRD spectrum using the out-of-plane method. In FIG. 19, the upper part shows the measurement results for the sample whose substrate temperature condition during film formation is 170 ° C., the middle part shows the measurement results for the sample whose substrate temperature condition during film formation is 130 ° C., and the lower part shows the measurement result during film formation. The substrate temperature condition of R.R. T.A. The measurement result in the sample is shown. The left column shows the measurement results for the sample with an oxygen gas flow ratio of 10%, the center column shows the measurement results for a sample with an oxygen gas flow ratio of 30%, and the right column shows the oxygen gas flow rate. The measurement result in the sample whose ratio condition is 100% is shown.

In the XRD spectrum shown in FIG. 19, the peak intensity near 2θ = 31 ° is increased by increasing the substrate temperature during film formation or increasing the ratio of the oxygen gas flow rate ratio during film formation. Note that the peak near 2θ = 31 ° is a crystalline IGZO compound (also referred to as CAAC (c-axis aligned crystalline) -IGZO) oriented in the c-axis with respect to a surface to be formed or an upper surface substantially perpendicular to the surface. Is known to originate from

In the XRD spectrum shown in FIG. 19, a clear peak did not appear as the substrate temperature during film formation was lower or the oxygen gas flow ratio was smaller. Therefore, it can be seen that the sample having a low substrate temperature during film formation or a small oxygen gas flow ratio does not show orientation in the ab plane direction and c-axis direction of the measurement region.

≪Analysis with electron microscope≫
In this item, the substrate temperature R.D. T.A. Samples prepared at a gas flow rate ratio of 10% and HAADF (High-Angle Angular Dark Field) -STEM (Scanning Transmission Electron Microscope) will be described and explained below (hereinafter obtained by HAADF-STEM). The image is also called a TEM image.)

The results of image analysis of a planar image (hereinafter also referred to as a planar TEM image) acquired by HAADF-STEM and a sectional image (hereinafter also referred to as a sectional TEM image) will be described. The TEM image was observed using a spherical aberration correction function. The HAADF-STEM image was taken by irradiating an electron beam with an acceleration voltage of 200 kV and a beam diameter of about 0.1 nmφ using an atomic resolution analytical electron microscope JEM-ARM200F manufactured by JEOL Ltd.

FIG. 20A shows the substrate temperature R.D. T.A. , And a plane TEM image of a sample fabricated at an oxygen gas flow rate ratio of 10%. FIG. 20B shows the substrate temperature R.P. T.A. And a cross-sectional TEM image of a sample manufactured at an oxygen gas flow rate ratio of 10%.

≪Analysis of electron diffraction pattern≫
In this item, the substrate temperature R.D. T.A. The result of acquiring an electron beam diffraction pattern by irradiating an electron beam having a probe diameter of 1 nm (also referred to as a nanobeam electron beam) to a sample manufactured at an oxygen gas flow rate ratio of 10% will be described.

As shown in FIG. 20A, the substrate temperature R.D. T.A. , And an electron beam diffraction pattern indicated by black spots a1, black spots a2, black spots a3, black spots a4, and black spots a5 in a planar TEM image of a sample prepared at an oxygen gas flow rate ratio of 10%. The observation of the electron beam diffraction pattern is performed while moving at a constant speed from the 0 second position to the 35 second position while irradiating the electron beam. FIG. 20C shows the result of black point a1, FIG. 20D shows the result of black point a2, FIG. 20E shows the result of black point a3, FIG. 19F shows the result of black point a4, and the result of black point a5. As shown in FIG.

From FIG. 20C, FIG. 20D, FIG. 20E, FIG. 20F, and FIG. 20G, it is possible to observe a high luminance region in a circle (in a ring shape). A plurality of spots can be observed in the ring-shaped region.

Further, as shown in FIG. T.A. In the cross-sectional TEM image of the sample manufactured at an oxygen gas flow rate ratio of 10%, the electron beam diffraction pattern indicated by black spot b1, black spot b2, black spot b3, black spot b4, and black spot b5 is observed. FIG. 20 (H) shows the result of black point b1, FIG. 20 (I) shows the result of black point b2, FIG. 20 (J) shows the result of black point b3, FIG. 20 (K) shows the result of black point b4, and FIG. As shown in FIG.

From FIG. 20 (H), FIG. 20 (I), FIG. 20 (J), FIG. 20 (K), and FIG. A plurality of spots can be observed in the ring-shaped region.

Here, for example, when an electron beam with a probe diameter of 300 nm is incident on a CAAC-OS having an InGaZnO ₄ crystal in parallel to the sample surface, spots resulting from the (009) plane of the InGaZnO ₄ crystal are included. A diffraction pattern is seen. That is, it can be seen that the CAAC-OS has c-axis orientation and the c-axis is in a direction substantially perpendicular to the formation surface or the top surface. On the other hand, when an electron beam with a probe diameter of 300 nm is incident on the same sample perpendicularly to the sample surface, a ring-shaped diffraction pattern is confirmed. That is, in the CAAC-OS, the a-axis and the b-axis do not have orientation.

Further, when electron beam diffraction using an electron beam with a large probe diameter (for example, 50 nm or more) is performed on an oxide semiconductor having microcrystals (hereinafter referred to as nc-OS), a halo pattern is obtained. A simple diffraction pattern is observed. Further, when nanobeam electron diffraction is performed on the nc-OS using an electron beam with a small probe diameter (for example, less than 50 nm), bright spots (spots) are observed. Further, when nanobeam electron diffraction is performed on the nc-OS, a region with high luminance may be observed so as to draw a circle (in a ring shape). In addition, a plurality of bright spots may be observed in the ring-shaped region.

Substrate temperature R.D. T.A. The electron beam diffraction pattern of a sample manufactured at an oxygen gas flow rate ratio of 10% has a ring-like high luminance region and a plurality of bright spots in the ring region. Therefore, the substrate temperature R.D. T.A. And the sample manufactured at an oxygen gas flow rate ratio of 10% has an electron beam diffraction pattern of nc-OS and has no orientation in the plane direction and the cross-sectional direction.

As described above, an oxide semiconductor with a low substrate temperature or a low oxygen gas flow ratio during deposition has properties that are clearly different from those of an amorphous oxide semiconductor film and a single crystal oxide semiconductor film. Can be estimated.

≪Elemental analysis≫
In this item, by using energy dispersive X-ray spectroscopy (EDX) and obtaining and evaluating EDX mapping, the substrate temperature R.D. T.A. The results of elemental analysis of a sample prepared at an oxygen gas flow rate ratio of 10% will be described. For EDX measurement, an energy dispersive X-ray analyzer JED-2300T manufactured by JEOL Ltd. is used as an element analyzer. A Si drift detector is used to detect X-rays emitted from the sample.

In the EDX measurement, each point in the analysis target region of the sample is irradiated with an electron beam, and the characteristic X-ray energy and the number of occurrences of the sample generated thereby are measured to obtain an EDX spectrum corresponding to each point. In this embodiment, the peak of the EDX spectrum at each point is represented by the electron transition of the In atom to the L shell, the electron transition of the Ga atom to the K shell, the electron transition of the Zn atom to the K shell, and the K shell of the O atom. And the ratio of each atom at each point is calculated. By performing this for the analysis target region of the sample, EDX mapping showing the distribution of the ratio of each atom can be obtained.

FIG. 21 shows the substrate temperature R.D. T.A. And EDX mapping in a cross section of a sample fabricated at an oxygen gas flow rate ratio of 10%. FIG. 21A is an EDX mapping of Ga atoms (the ratio of Ga atoms to all atoms is in the range of 1.18 to 18.64 [atomic%]). FIG. 21B is EDX mapping of In atoms (the ratio of In atoms to all atoms is in the range of 9.28 to 33.74 [atomic%]). FIG. 21C is EDX mapping of Zn atoms (the ratio of Zn atoms to all atoms is in the range of 6.69 to 24.99 [atomic%]). 21A, 21B, and 21C show the substrate temperature R.P. at the time of film formation. T.A. In a cross section of a sample manufactured at an oxygen gas flow rate ratio of 10%, a region in the same range is shown. Note that the EDX mapping shows the ratio of elements in light and dark so that the more measurement elements in the range, the brighter the brightness, and the darker the measurement elements. Further, the magnification of the EDX mapping shown in FIG. 21 is 7.2 million times.

In the EDX mapping shown in FIGS. 21A, 21B, and 21C, a relative light / dark distribution is seen in the image, and the substrate temperature R.D. T.A. In the sample prepared at an oxygen gas flow rate ratio of 10%, it can be confirmed that each atom exists in a distributed manner. Here, attention is focused on a range surrounded by a solid line and a range surrounded by a broken line in FIGS. 21A, 21B, and 21C.

In FIG. 21A, a range surrounded by a solid line includes many relatively dark areas, and a range surrounded by a broken line includes many relatively bright areas. In FIG. 21B, a range surrounded by a solid line includes many relatively bright areas, and a range surrounded by a broken line includes many relatively dark areas.

That is, the range surrounded by the solid line is a region having a relatively large number of In atoms, and the range surrounded by a broken line is a region having a relatively small number of In atoms. Here, in FIG. 21C, the right side is a relatively bright region and the left side is a relatively dark region in a range surrounded by a solid line. Accordingly, the range surrounded by the solid line is a region mainly composed of In _X2 Zn _Y2 O _Z2 or InO _X1 .

A range surrounded by a solid line is a region with relatively few Ga atoms, and a range surrounded by a broken line is a region with relatively many Ga atoms. In FIG. 21C, in the range surrounded by the broken line, the upper left region is a relatively bright region, and the lower right region is a relatively dark region. Therefore, a range surrounded by a broken line is a region whose main component is GaO _X3 , Ga _X4 Zn _Y4 O _Z4 , or the like.

Further, from FIGS. 21A, 21B, and 21C, the distribution of In atoms is relatively more uniform than Ga atoms, and InO _X1 is the main component. The regions appear to be connected to each other through a region mainly composed of In _X2 Zn _Y2 O _Z2 . As described above, the region mainly composed of In _X2 Zn _Y2 O _Z2 or InO _X1 is formed so as to spread in a cloud shape.

Thus, the region which is the main component such as _{GaO X3, In X2 Zn Y2 O} Z2 or _{InO X1} there is a region which is a main component, ubiquitously, an In-Ga-Zn oxide having a mixed to have the structure Things can be referred to as CAC-OS.

The crystal structure in the CAC-OS has an nc structure. The nc structure of CAC-OS has several bright spots (spots) in addition to bright spots (spots) caused by IGZO including single crystal, polycrystal, or CAAC structure in the electron diffraction image. Have. Alternatively, in addition to several bright spots (spots), a crystal structure is defined as a region having a high brightness in a ring shape.

Further, FIG. 21 (A), the FIG. 21 (B), the and 21 from (C), such as _{GaO X3} is the main component area, and _In X2 _Zn Y2 _{O Z2} or _{InO X1} is a region which is the main component, The size is observed from 0.5 nm to 10 nm, or from 1 nm to 3 nm. Preferably, in EDX mapping, the diameter of a region in which each element is a main component is 1 nm or more and 2 nm or less.

As described above, the CAC-OS has a structure different from that of the IGZO compound in which the metal elements are uniformly distributed and has properties different from those of the IGZO compound. That is, in the CAC-OS, a region in which GaO _X3 or the like is a main component and a region in which In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component are phase-separated from each other, and each region is mainly composed of each element. Has a mosaic structure.

Here, the region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is a region having higher conductivity than a region containing GaO _X3 or the like as a main component. _That, In _{X2 Zn} Y2 _{O Z2} or _{InO X1,} is an area which is the main component, by carriers flow, expressed the conductivity of the oxide semiconductor. Therefore, a region where In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component is distributed in a cloud shape in the oxide semiconductor, whereby high field-effect mobility (μ) can be realized.

On the other hand, areas such as _{GaO X3} is the main _component, as compared to the In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component area, it is highly regions insulating. That is, a region containing GaO _X3 or the like as a main component is distributed in the oxide semiconductor, whereby leakage current can be suppressed and good switching operation can be realized.

Therefore, when CAC-OS is used for a semiconductor element, the insulating property caused by GaO _{X3 and the} like and the conductivity caused by In _X2 Zn _Y2 O _Z2 or InO _X1 act complementarily, thereby increasing the An on-current (I _on ) and high field effect mobility (μ) can be realized.

In addition, a semiconductor element using a CAC-OS has high reliability. Therefore, the CAC-OS is optimal for various semiconductor devices including a display.

Alternatively, silicon may be used for the semiconductor in which the channel of the transistor is formed. Although amorphous silicon may be used as silicon, it is particularly preferable to use silicon having crystallinity. For example, microcrystalline silicon, polycrystalline silicon, single crystal silicon, or the like is preferably used. In particular, polycrystalline silicon can be formed at a lower temperature than single crystal silicon, and has higher field effect mobility and higher reliability than amorphous silicon.

The bottom-gate transistor described in this embodiment is preferable because the number of manufacturing steps can be reduced. At this time, since amorphous silicon can be used at a lower temperature than polycrystalline silicon, it is possible to use a material having low heat resistance as the electrode material and substrate material for the wiring below the semiconductor layer. Can widen the choice of materials. For example, a glass substrate having an extremely large area can be suitably used. On the other hand, a top-gate transistor is preferable because an impurity region can be easily formed in a self-aligning manner and variation in characteristics can be reduced. At this time, it is particularly suitable when polycrystalline silicon, single crystal silicon or the like is used.

[Conductive layer]
In addition to the gate, source, and drain of a transistor, materials that can be used for conductive layers such as various wirings and electrodes that constitute a display device include aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, A metal such as tantalum or tungsten, or an alloy containing the same as a main component can be given. A film containing any of these materials can be used as a single layer or a stacked structure. For example, a single layer structure of an aluminum film containing silicon, a two layer structure in which an aluminum film is stacked on a titanium film, a two layer structure in which an aluminum film is stacked on a tungsten film, and a copper film on a copper-magnesium-aluminum alloy film Two-layer structure to stack, two-layer structure to stack copper film on titanium film, two-layer structure to stack copper film on tungsten film, titanium film or titanium nitride film, and aluminum film or copper film on top of it A three-layer structure for forming a titanium film or a titanium nitride film thereon, a molybdenum film or a molybdenum nitride film, and an aluminum film or a copper film stacked thereon, and a molybdenum film or a There is a three-layer structure for forming a molybdenum nitride film. Note that an oxide such as indium oxide, tin oxide, or zinc oxide may be used. Further, it is preferable to use copper containing manganese because the controllability of the shape by etching is increased.

As the light-transmitting conductive material, conductive oxide such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zinc oxide to which gallium is added, or graphene can be used. Alternatively, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or an alloy material containing the metal material can be used. Alternatively, a nitride (eg, titanium nitride) of the metal material may be used. Note that in the case where a metal material or an alloy material (or a nitride thereof) is used, it may be thin enough to have a light-transmitting property. In addition, a stacked film of the above materials can be used as a conductive layer. For example, it is preferable to use a laminated film of an alloy of silver and magnesium and indium tin oxide because the conductivity can be increased. These can also be used for conductive layers such as various wirings and electrodes constituting the display device and conductive layers (conductive layers functioning as pixel electrodes and common electrodes) included in the display element.

[Insulation layer]
Insulating materials that can be used for each insulating layer include, for example, resins such as acrylic and epoxy, resins having a siloxane bond, and inorganic insulation such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide. Materials can also be used.

In addition, the light-emitting element is preferably provided between a pair of insulating films with low water permeability. Thereby, impurities such as water can be prevented from entering the light emitting element, and a decrease in reliability of the apparatus can be suppressed.

Examples of the low water-permeable insulating film include a film containing nitrogen and silicon such as a silicon nitride film and a silicon nitride oxide film, and a film containing nitrogen and aluminum such as an aluminum nitride film. Alternatively, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

For example, the water vapor transmission rate of an insulating film with low water permeability is 1 × 10 ⁻⁵ [g / (m ² · day)] or less, preferably 1 × 10 ⁻⁶ [g / (m ² · day)] or less, More preferably, it is 1 × 10 ⁻⁷ [g / (m ² · day)] or less, and further preferably 1 × 10 ⁻⁸ [g / (m ² · day)] or less.

[Liquid crystal element]
As the liquid crystal element, for example, a liquid crystal element to which a vertical alignment (VA: Vertical Alignment) mode is applied can be used. As the vertical alignment mode, an MVA (Multi-Domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, an ASV (Advanced Super View) mode, or the like can be used.

As the liquid crystal element, liquid crystal elements to which various modes are applied can be used. For example, in addition to the VA mode, a TN (Twisted Nematic) mode, an IPS (In-Plane-Switching) mode, an FFS (Fringe Field Switching) mode, an ASM (Axially Symmetrical Aligned Micro-cell) mode, Further, a liquid crystal element to which an FLC (Ferroelectric Liquid Crystal) mode, an AFLC (Antiferroelectric Liquid Crystal) mode, or the like is applied can be used.

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. Note that the optical modulation action of the liquid crystal is controlled by an electric field applied to the liquid crystal (including a horizontal electric field, a vertical electric field, or an oblique electric field). As the liquid crystal used in the liquid crystal element, a thermotropic liquid crystal, a low molecular liquid crystal, a polymer liquid crystal, a polymer dispersed liquid crystal (PDLC), a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or the like is used. Can do. These liquid crystal materials exhibit a cholesteric phase, a smectic phase, a cubic phase, a chiral nematic phase, an isotropic phase, and the like depending on conditions.

Further, as the liquid crystal material, either a positive type liquid crystal or a negative type liquid crystal may be used, and an optimal liquid crystal material may be used according to an applied mode or design.

An alignment film can be provided to control the alignment of the liquid crystal. Note that in the case of employing a horizontal electric field mode, liquid crystal exhibiting a blue phase for which an alignment film is unnecessary may be used. The blue phase is one of the liquid crystal phases. When the temperature of the cholesteric liquid crystal is increased, the blue phase appears immediately before the transition from the cholesteric phase to the isotropic phase. Since the blue phase appears only in a narrow temperature range, a liquid crystal composition mixed with several percent by weight or more of a chiral agent is used for the liquid crystal layer in order to improve the temperature range. A liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent has a short response speed and is optically isotropic. In addition, a liquid crystal composition including a liquid crystal exhibiting a blue phase and a chiral agent does not require alignment treatment and has a small viewing angle dependency. Further, since it is not necessary to provide an alignment film, a rubbing process is not required, so that electrostatic breakdown caused by the rubbing process can be prevented, and defects or breakage of the liquid crystal display device during the manufacturing process can be reduced. .

As the liquid crystal element, a transmissive liquid crystal element, a reflective liquid crystal element, a transflective liquid crystal element, or the like can be used.

In one embodiment of the present invention, a reflective liquid crystal element can be used.

In the case of using a transmissive or transflective liquid crystal element, two polarizing plates are provided so as to sandwich a pair of substrates. A backlight is provided outside the polarizing plate. The backlight may be a direct type backlight or an edge light type backlight. It is preferable to use a direct-type backlight including an LED (Light Emitting Diode) because local dimming is facilitated and contrast can be increased. An edge light type backlight is preferably used because the thickness of the module including the backlight can be reduced.
Therefore, it is preferable.

In the case of using a reflective liquid crystal element, a polarizing plate is provided on the display surface side. Separately from this, it is preferable to arrange a light diffusing plate on the display surface side because the visibility can be improved.

In the case of using a reflective or transflective liquid crystal element, a front light may be provided outside the polarizing plate. As the front light, an edge light type front light is preferably used. It is preferable to use a front light including an LED (Light Emitting Diode) because power consumption can be reduced.

(Adhesive layer)
As the adhesive layer, various curable adhesives such as an ultraviolet curable photocurable adhesive, a reactive curable adhesive, a thermosetting adhesive, and an anaerobic adhesive can be used. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenol resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, EVA (ethylene vinyl acetate) resins, and the like. In particular, a material with low moisture permeability such as an epoxy resin is preferable. Alternatively, a two-component mixed resin may be used. Further, an adhesive sheet or the like may be used.

Further, the resin may contain a desiccant. For example, a substance that adsorbs moisture by chemical adsorption, such as an alkaline earth metal oxide (such as calcium oxide or barium oxide), can be used. Alternatively, a substance that adsorbs moisture by physical adsorption, such as zeolite or silica gel, may be used. The inclusion of a desiccant is preferable because impurities such as moisture can be prevented from entering the element and the reliability of the display panel is improved.

In addition, light extraction efficiency can be improved by mixing a filler having a high refractive index or a light scattering member with the resin. For example, titanium oxide, barium oxide, zeolite, zirconium, or the like can be used.

(Colored layer)
Examples of materials that can be used for the colored layer include metal materials, resin materials, resin materials containing pigments or dyes, and the like. As the color element, red, green, blue, or the like can be used. Further, cyan, magenta, yellow (yellow), or the like may be used. The phrase “transmitting only colored light” means that the light transmitted through the colored layer has a peak at the wavelength of the chromatic light.

[Light shielding layer]
Examples of the material that can be used for the light-shielding layer include carbon black, titanium black, metal, metal oxide, and composite oxide containing a solid solution of a plurality of metal oxides. The light shielding layer may be a film containing a resin material or a thin film of an inorganic material such as a metal. Alternatively, a stacked film of a film containing a material for the colored layer can be used for the light shielding layer. For example, a stacked structure of a film including a material used for a colored layer that transmits light of a certain color and a film including a material used for a colored layer that transmits light of another color can be used. It is preferable to use a common material for the coloring layer and the light-shielding layer because the apparatus can be shared and the process can be simplified.

〔Structure〕
The first structure body 124 and the second structure body 126 include a material that transmits at least light. In addition, a reflective material may be used for the reflective film 124 </ b> R included in the first structure body 124. Note that the second structure body 126 may also be provided with a reflective film.

(Light extraction part)
As the light extraction portion 122R, a minute lens-like structure such as a microlens can be used. A material that transmits visible light can be used for the light extraction portion 122R. Alternatively, a material having a refractive index of 1.3 to 2.5 can be used for the light extraction portion 122R. For example, an inorganic material or an organic material can be preferably used.

Specifically, the light extraction portion 122R includes cerium oxide, hafnium oxide, lanthanum oxide, magnesium oxide, niobium oxide, tantalum oxide, titanium oxide, yttrium oxide, zinc oxide, an oxide containing indium and tin, or indium and gallium. An oxide containing zinc and zinc can be used. Alternatively, zinc sulfide or the like may be used.

Alternatively, a material including a resin can be used for the light extraction portion 122R. Specifically, a resin into which chlorine, bromine or iodine is introduced, a resin into which heavy metal atoms are introduced, a resin into which an aromatic ring is introduced, a resin into which sulfur is introduced, or the like can be used. Alternatively, a resin including a resin and nanoparticles of a material having a higher refractive index than the resin can be used. Titanium oxide or zirconium oxide can be used for the nanoparticles.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 4)
In this embodiment, examples of transistors that can be used instead of the transistors described in the above embodiments will be described with reference to drawings.

The display device of one embodiment of the present invention can be manufactured using various types of transistors such as a bottom-gate transistor and a top-gate transistor. Therefore, the semiconductor layer material and the transistor structure to be used can be easily replaced in accordance with an existing production line.

[Bottom gate type transistor]
FIG. 22A1 is a cross-sectional view of a channel protection transistor 810 which is a kind of bottom-gate transistor. In FIG. 22A1, the transistor 810 is formed over a substrate 771. In addition, the transistor 810 includes an electrode 746 over the substrate 771 with an insulating layer 772 interposed therebetween. In addition, a semiconductor layer 742 is provided over the electrode 746 with an insulating layer 726 interposed therebetween. The electrode 746 can function as a gate electrode. The insulating layer 726 can function as a gate insulating layer.

In addition, the insulating layer 741 is provided over the channel formation region of the semiconductor layer 742. Further, an electrode 744 a and an electrode 744 b are provided over the insulating layer 726 in contact with part of the semiconductor layer 742. The electrode 744a can function as one of a source electrode and a drain electrode. The electrode 744b can function as the other of the source electrode and the drain electrode. Part of the electrode 744 a and part of the electrode 744 b are formed over the insulating layer 741.

The insulating layer 741 can function as a channel protective layer. By providing the insulating layer 741 over the channel formation region, it is possible to prevent the semiconductor layer 742 from being exposed when the electrodes 744a and 744b are formed. Accordingly, the channel formation region of the semiconductor layer 742 can be prevented from being etched when the electrodes 744a and 744b are formed. According to one embodiment of the present invention, a transistor with favorable electrical characteristics can be realized.

The transistor 810 includes the insulating layer 728 over the electrode 744a, the electrode 744b, and the insulating layer 741, and the insulating layer 729 over the insulating layer 728.

In the case where an oxide semiconductor is used for the semiconductor layer 742, a material that can take oxygen from part of the semiconductor layer 742 and generate oxygen vacancies at least in a portion of the electrodes 724a and 724b in contact with the semiconductor layer 742 is used. It is preferable. In the region where oxygen vacancies occur in the semiconductor layer 742, the carrier concentration increases, and the region becomes n-type and becomes an n-type region (n ⁺ layer). Accordingly, the region can function as a source region or a drain region. In the case where an oxide semiconductor is used for the semiconductor layer 742, tungsten, titanium, or the like can be given as an example of a material that can take oxygen from the semiconductor layer 742 and generate oxygen vacancies.

When the source region and the drain region are formed in the semiconductor layer 742, the contact resistance between the electrode 724a and the electrode 724b and the semiconductor layer 742 can be reduced. Thus, favorable electric characteristics of the transistor, such as field effect mobility and threshold voltage, can be obtained.

In the case where a semiconductor such as silicon is used for the semiconductor layer 742, a layer functioning as an n-type semiconductor or a p-type semiconductor is preferably provided between the semiconductor layer 742 and the electrode 724a and between the semiconductor layer 742 and the electrode 724b. A layer functioning as an n-type semiconductor or a p-type semiconductor can function as a source region or a drain region of a transistor.

The insulating layer 729 is preferably formed using a material having a function of preventing or reducing the diffusion of impurities from the outside to the transistor. Note that the insulating layer 729 can be omitted as necessary.

A transistor 811 illustrated in FIG. 22A2 is different from the transistor 810 in that the transistor 811 includes an electrode 723 that can function as a back gate electrode over the insulating layer 729. The electrode 723 can be formed using a material and a method similar to those of the electrode 746.

In general, the back gate electrode is formed using a conductive layer, and the channel formation region of the semiconductor layer is sandwiched between the gate electrode and the back gate electrode. Therefore, the back gate electrode can function in the same manner as the gate electrode. The potential of the back gate electrode may be the same as that of the gate electrode, or may be a ground potential (GND potential) or an arbitrary potential. In addition, the threshold voltage of the transistor can be changed by changing the potential of the back gate electrode independently of the gate electrode.

Both the electrode 746 and the electrode 723 can function as gate electrodes. Thus, each of the insulating layer 726, the insulating layer 729, the insulating layer 728, and the insulating layer 729 can function as a gate insulating layer. Note that the electrode 723 may be provided between the insulating layer 728 and the insulating layer 729.

Note that when one of the electrode 746 and the electrode 723 is referred to as a “gate electrode”, the other is referred to as a “back gate electrode”. For example, in the transistor 811, when the electrode 723 is referred to as a “gate electrode”, the electrode 746 is referred to as a “back gate electrode”. In the case where the electrode 723 is used as a “gate electrode”, the transistor 811 can be regarded as a kind of top-gate transistor. One of the electrode 746 and the electrode 723 may be referred to as a “first gate electrode”, and the other may be referred to as a “second gate electrode”.

By providing the electrode 746 and the electrode 723 with the semiconductor layer 742 interposed therebetween, and further by setting the electrode 746 and the electrode 723 to have the same potential, a region where carriers flow in the semiconductor layer 742 becomes larger in the film thickness direction. The amount of carrier movement increases. As a result, the on-state current of the transistor 811 increases and the field-effect mobility increases.

Therefore, the transistor 811 is a transistor having a large on-state current with respect to the occupied area. In other words, the area occupied by the transistor 811 can be reduced with respect to the required on-state current. According to one embodiment of the present invention, the area occupied by a transistor can be reduced. Thus, according to one embodiment of the present invention, a highly integrated semiconductor device can be realized.

In addition, since the gate electrode and the back gate electrode are formed using conductive layers, they have a function of preventing an electric field generated outside the transistor from acting on a semiconductor layer in which a channel is formed (particularly, an electric field shielding function against static electricity). . Note that the electric field shielding function can be improved by forming the back gate electrode larger than the semiconductor layer and covering the semiconductor layer with the back gate electrode.

In addition, when the back gate electrode is formed using a light-blocking conductive film, light can be prevented from entering the semiconductor layer from the back gate electrode side. Therefore, light deterioration of the semiconductor layer can be prevented, and deterioration of electrical characteristics such as shift of the threshold voltage of the transistor can be prevented.

According to one embodiment of the present invention, a highly reliable transistor can be realized. In addition, a highly reliable semiconductor device can be realized.

FIG. 22B1 is a cross-sectional view of a channel protection transistor 820 which is one of bottom-gate transistors. The transistor 820 has substantially the same structure as the transistor 810, except that an insulating layer 741 covers an end portion of the semiconductor layer 742. In addition, the semiconductor layer 742 and the electrode 744a are electrically connected to each other in an opening formed by selectively removing part of the insulating layer 729 which overlaps with the semiconductor layer 742. In addition, the semiconductor layer 742 and the electrode 744b are electrically connected to each other in an opening formed by selectively removing part of the insulating layer 729 which overlaps with the semiconductor layer 742. A region of the insulating layer 729 overlapping with a channel formation region can function as a channel protective layer.

A transistor 821 illustrated in FIG. 22B2 is different from the transistor 820 in that the transistor 821 includes an electrode 723 that can function as a back gate electrode over the insulating layer 729.

By providing the insulating layer 729, exposure of the semiconductor layer 742 that occurs when the electrodes 744a and 744b are formed can be prevented. Therefore, the semiconductor layer 742 can be prevented from being thinned when the electrodes 744a and 744b are formed.

Further, in the transistor 820 and the transistor 821, the distance between the electrode 744a and the electrode 746 and the distance between the electrode 744b and the electrode 746 are longer than those in the transistor 810 and the transistor 811. Thus, parasitic capacitance generated between the electrode 744a and the electrode 746 can be reduced. In addition, parasitic capacitance generated between the electrode 744b and the electrode 746 can be reduced. According to one embodiment of the present invention, a transistor with favorable electrical characteristics can be realized.

A transistor 825 illustrated in FIG. 22C1 is a channel-etched transistor which is one of bottom-gate transistors. In the transistor 825, the electrode 744a and the electrode 744b are formed without using the insulating layer 729. Therefore, part of the semiconductor layer 742 exposed when the electrodes 744a and 744b are formed may be etched. On the other hand, since the insulating layer 729 is not provided, the productivity of the transistor can be increased.

A transistor 825 illustrated in FIG. 22C2 is different from the transistor 820 in that the transistor 825 includes an electrode 723 that can function as a back gate electrode over the insulating layer 729.

[Top gate type transistor]
FIG. 23A1 is a cross-sectional view of a transistor 830 which is a kind of top-gate transistor. The transistor 830 includes a semiconductor layer 742 over the insulating layer 772, and an electrode 744a in contact with part of the semiconductor layer 742 and an electrode 744b in contact with part of the semiconductor layer 742 over the semiconductor layer 742 and the insulating layer 772. An insulating layer 726 is provided over the semiconductor layer 742, the electrode 744a, and the electrode 744b, and an electrode 746 is provided over the insulating layer 726.

The transistor 830 reduces the parasitic capacitance generated between the electrode 746 and the electrode 744a and the parasitic capacitance generated between the electrode 746 and the electrode 744b because the electrode 746 and the electrode 744a and the electrode 746 and the electrode 744b do not overlap with each other. be able to. In addition, after the electrode 746 is formed, an impurity region can be formed in the semiconductor layer 742 in a self-alignment manner by introducing the impurity 755 into the semiconductor layer 742 using the electrode 746 as a mask ( (See FIG. 22 (A3)). According to one embodiment of the present invention, a transistor with favorable electrical characteristics can be realized.

Note that the impurity 755 can be introduced using an ion implantation apparatus, an ion doping apparatus, or a plasma treatment apparatus.

As the impurity 755, for example, at least one element of a Group 13 element or a Group 15 element can be used. In the case where an oxide semiconductor is used for the semiconductor layer 742, at least one element of a rare gas, hydrogen, and nitrogen can be used as the impurity 755.

A transistor 831 illustrated in FIG. 23A2 is different from the transistor 830 in that the transistor 831 includes an electrode 723 and an insulating layer 727. The transistor 831 includes an electrode 723 formed over the insulating layer 772 and an insulating layer 727 formed over the electrode 723. The electrode 723 can function as a back gate electrode. Thus, the insulating layer 727 can function as a gate insulating layer. The insulating layer 727 can be formed using a material and a method similar to those of the insulating layer 726.

Like the transistor 811, the transistor 831 is a transistor having a large on-state current with respect to the occupied area. In other words, the area occupied by the transistor 831 can be reduced with respect to the required on-state current. According to one embodiment of the present invention, the area occupied by a transistor can be reduced. Thus, according to one embodiment of the present invention, a highly integrated semiconductor device can be realized.

A transistor 840 illustrated in FIG. 23B1 is one of top-gate transistors. The transistor 840 is different from the transistor 830 in that the semiconductor layer 742 is formed after the electrodes 744a and 744b are formed. A transistor 841 illustrated in FIG. 23B2 is different from the transistor 840 in that the transistor 841 includes an electrode 723 and an insulating layer 727. In the transistors 840 and 841, part of the semiconductor layer 742 is formed over the electrode 744a, and the other part of the semiconductor layer 742 is formed over the electrode 744b.

Like the transistor 811, the transistor 841 is a transistor having a large on-state current with respect to the occupied area. That is, the area occupied by the transistor 841 can be reduced with respect to the required on-state current. According to one embodiment of the present invention, the area occupied by a transistor can be reduced. Thus, according to one embodiment of the present invention, a highly integrated semiconductor device can be realized.

A transistor 842 illustrated in FIG. 24A1 is one of top-gate transistors. The transistor 842 is different from the transistors 830 and 840 in that the electrode 744a and the electrode 744b are formed after the insulating layer 729 is formed. The electrodes 744 a and 744 b are electrically connected to the semiconductor layer 742 in openings formed in the insulating layers 728 and 729.

Further, part of the insulating layer 726 which does not overlap with the electrode 746 is removed, and the impurity 755 is introduced into the semiconductor layer 742 using the electrode 746 and the remaining insulating layer 726 as a mask, so that self-alignment in the semiconductor layer 742 ( Impurity regions can be formed in a self-alignment manner (see FIG. 23A3). The transistor 842 has a region where the insulating layer 726 extends beyond the end portion of the electrode 746. When the impurity 755 is introduced into the semiconductor layer 742, the impurity concentration of the region where the impurity 755 is introduced through the insulating layer 726 of the semiconductor layer 742 is higher than the region where the impurity 755 is introduced without passing through the insulating layer 726. Get smaller. Thus, an LDD (Lightly Doped Drain) region is formed in the region of the semiconductor layer 742 adjacent to the electrode 746.

A transistor 843 illustrated in FIG. 24A2 is different from the transistor 842 in that the electrode 723 is provided. The transistor 843 includes an electrode 723 formed over the substrate 771 and overlaps with the semiconductor layer 742 with the insulating layer 772 interposed therebetween. The electrode 723 can function as a back gate electrode.

Alternatively, as in the transistor 844 illustrated in FIG. 24B1 and the transistor 845 illustrated in FIG. 24B2, the insulating layer 726 in a region which does not overlap with the electrode 746 may be removed. Further, the insulating layer 726 may be left as in the transistor 846 illustrated in FIG. 24C1 and the transistor 847 illustrated in FIG.

The transistors 842 to 847 can also form impurity regions in the semiconductor layer 742 in a self-aligned manner by introducing the impurity 755 into the semiconductor layer 742 using the electrode 746 as a mask after the electrode 746 is formed. . According to one embodiment of the present invention, a transistor with favorable electrical characteristics can be realized. According to one embodiment of the present invention, a highly integrated semiconductor device can be realized.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 5)
In this embodiment, a display module that can be manufactured using one embodiment of the present invention will be described.

A display module 6000 illustrated in FIG. 25A includes a display panel 6006 connected to an FPC 6005, a frame 6009, a printed board 6010, and a battery 6011 between an upper cover 6001 and a lower cover 6002.

For example, a display device manufactured using one embodiment of the present invention can be used for the display panel 6006. Thereby, a display module can be manufactured with a high yield.

The shapes and dimensions of the upper cover 6001 and the lower cover 6002 can be changed as appropriate in accordance with the size of the display panel 6006.

The display panel 6006 is provided with the input device of one embodiment of the present invention.

The frame 6009 has a function as an electromagnetic shield for blocking electromagnetic waves generated by the operation of the printed board 6010 in addition to a protective function of the display panel 6006. The frame 6009 may function as a heat sink.

The printed board 6010 includes a power supply circuit, a signal processing circuit for outputting a video signal and a clock signal. The power source for supplying power to the power supply circuit may be an external commercial power source or a power source by a battery 6011 provided separately. The battery 6011 can be omitted when a commercial power source is used.

The display module 6000 may be additionally provided with a member such as a polarizing plate, a retardation plate, or a prism sheet.

FIG. 25B is a schematic cross-sectional view of a display module 6000 including an optical touch sensor.

The display module 6000 includes a light emitting unit 6015 and a light receiving unit 6016 provided on the printed board 6010. Further, a region surrounded by the upper cover 6001 and the lower cover 6002 has a pair of light guide portions (light guide portion 6017a and light guide portion 6017b).

For the upper cover 6001 and the lower cover 6002, for example, plastic can be used. Further, the upper cover 6001 and the lower cover 6002 can each be thin (for example, 0.5 mm to 5 mm). Therefore, the display module 6000 can be made extremely light. Further, since the upper cover 6001 and the lower cover 6002 can be manufactured with a small amount of material, manufacturing cost can be reduced.

The display panel 6006 is provided to overlap the printed circuit board 6010 and the battery 6011 with a frame 6009 interposed therebetween. The display panel 6006 and the frame 6009 are fixed to the light guide unit 6017a and the light guide unit 6017b.

Light 6018 emitted from the light emitting unit 6015 passes through the upper part of the display panel 6006 by the light guide unit 6017a and reaches the light receiving unit 6016 through the light guide unit 6017b. For example, the touch operation can be detected by blocking the light 6018 by a detection target such as a finger or a stylus.

For example, a plurality of light emitting units 6015 are provided along two adjacent sides of the display panel 6006. A plurality of light receiving portions 6016 are provided at positions facing the light emitting portion 6015 with the display panel 6006 interposed therebetween. Thereby, the information on the position where the touch operation is performed can be acquired.

For the light emitting unit 6015, for example, a light source such as an LED element can be used. In particular, it is preferable to use a light source that emits infrared rays that are not visually recognized by the user and harmless to the user as the light emitting unit 6015.

The light receiving unit 6016 can be a photoelectric element that receives light emitted from the light emitting unit 6015 and converts the light into an electrical signal. Preferably, a photodiode capable of receiving infrared light can be used.

As the light guide portion 6017a and the light guide portion 6017b, a member that transmits at least the light 6018 can be used. By using the light guide unit 6017a and the light guide unit 6017b, the light emitting unit 6015 and the light receiving unit 6016 can be arranged below the display panel 6006, and external light reaches the light receiving unit 6016 and the touch sensor malfunctions. Can be suppressed. In particular, it is preferable to use a resin that absorbs visible light and transmits infrared rays. Thereby, malfunction of a touch sensor can be controlled more effectively.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 6)
Electronic devices that can use the display system according to one embodiment of the present invention include a display device, a personal computer, an image storage device or an image playback device including a recording medium, a mobile phone, a portable game machine, and a portable data terminal , Digital book terminals, video cameras, digital still cameras and other cameras, goggles-type displays (head-mounted displays), navigation systems, sound playback devices (car audio, digital audio players, etc.), copiers, facsimiles, printers, printer multifunction devices Automatic teller machines (ATMs), vending machines, and the like. Specific examples of these electronic devices are shown in FIGS.

FIG. 26A illustrates a television which includes a housing 971, a display portion 973, operation keys 974, speakers 975, a communication connection terminal 976, an optical sensor 977, and the like. The display portion 973 is provided with a touch sensor and can perform an input operation. By using the display device of one embodiment of the present invention for the display portion 973, power consumption can be reduced.

FIG. 26B illustrates an information processing terminal, which includes a housing 901, a display portion 902, a display portion 903, a sensor 904, and the like. The display portion 902 and the display portion 903 are formed of a single display panel and have flexibility. The housing 901 is also flexible and can be used by being bent as illustrated, or can be used in a flat plate shape like a tablet terminal. The sensor 904 can sense the shape of the housing 901. For example, the display of the display portion 902 and the display portion 903 can be switched when the housing is bent. By using the display device of one embodiment of the present invention for the display portion 902 and the display portion 903, power consumption can be reduced.

FIG. 26C illustrates a digital camera, which includes a housing 961, a shutter button 962, a microphone 963, a speaker 967, a display portion 965, operation keys, and the like. By using the display system of one embodiment of the present invention for the display portion 965, power consumption can be reduced.

FIG. 26D illustrates a wristwatch type information terminal, which includes a housing 931, a display portion 932, a wristband 933, operation buttons 935, a crown 936, a camera 939, and the like. The display unit 932 may be a touch panel. By using the display device of one embodiment of the present invention for the display portion 932, power consumption can be reduced.

FIG. 26E illustrates an example of a mobile phone, which includes a housing 951, a display portion 952, operation buttons 953, an external connection port 954, a speaker 955, a microphone 956, a camera 957, and the like. The mobile phone includes a touch sensor in the display portion 952. All operations such as making a call or inputting characters can be performed by touching the display portion 952 with a finger or a stylus. By using the display device of one embodiment of the present invention for the display portion 952, power consumption can be reduced.

FIG. 26F illustrates a portable data terminal, which includes a housing 911, a display portion 912, a camera 919, and the like. Information can be input and output by a touch panel function of the display portion 912. By using the display device of one embodiment of the present invention for the display portion 932, power consumption can be reduced.

27A, 27B, and 27C illustrate electronic devices that can be folded, respectively.

An electronic device 920 illustrated in FIG. 27A includes a housing 921a, a housing 921b, a hinge 923, a display portion 922, and the like. The display portion 922 is incorporated in the housing 921 and the housing 921b.

The housing 921a and the housing 921b are rotatably connected by a hinge 923. The electronic device 920 can be deformed into a state where the housing 921a and the housing 921b are closed and an opened state as illustrated in FIG. Thereby, when carrying, it is excellent in portability, and when using, it is excellent in visibility by a large display area.

Further, the hinge 923 preferably has a lock mechanism so that when the housing 921a and the housing 921b are opened, these angles do not become larger than a predetermined angle. For example, the angle at which the lock is applied (which does not open any more) is preferably 90 degrees or more and less than 180 degrees, typically 90 degrees, 120 degrees, 135 degrees, 150 degrees, 175 degrees, or the like. be able to. Thereby, convenience, safety, and reliability can be improved.

The display portion 922 functions as a touch panel and can be operated with a finger, a stylus, or the like.

One of the housing 921a and the housing 921b is provided with a wireless communication module, and data is transmitted via a computer network such as the Internet, a LAN (Local Area Network), and Wi-Fi (Wireless Fidelity: registered trademark). It is possible to send and receive.

It is preferable that the display unit 922 includes a single flexible display. Accordingly, it is possible to perform continuous display without interruption between the housing 921a and the housing 901b. Note that a display may be provided in each of the housing 921a and the housing 921b.

FIG. 27B illustrates an electronic device 940 that functions as a portable game machine. The electronic device 940 includes a housing 941a, a housing 941b, a display portion 942, a hinge 943, operation buttons 944a, operation buttons 944b, and the like.

Further, a cartridge 945 can be inserted into the housing 941b. The cartridge 945 stores application software such as a game, for example, and various applications can be executed by the electronic device 940 by exchanging the cartridge 945.

FIG. 27B illustrates an example in which the size of a portion of the display portion 912 that overlaps with the housing 941a is different from the size of a portion of the display portion 912 that overlaps with the housing 941b. Specifically, a part of the display portion 942 provided in the housing 941a is larger than a part of the display portion 942 overlapping with the housing 941b in which the operation buttons 944a and 944b are provided. For example, each display unit can be used properly, such as displaying the main screen on the housing 941a side of the display unit 942 and displaying the operation screen on the housing 941b side.

In the electronic device 980 illustrated in FIG. 27C, a flexible display portion 982 is provided over the housing 981a and the housing 981b which are connected to each other with a hinge 983.

In FIG. 27C, when the housing 981a and the housing 981b are opened, the display portion 982 is held in a largely curved form. For example, the display portion 982 can be held in a state where the curvature radius is 1 mm to 50 mm, preferably 5 mm to 30 mm. Part of the display portion 982 can display a curved surface by continuously arranging pixels from the housing 981a to the housing 981b.

Since the hinge 983 has the lock mechanism described above, the display portion 982 can be prevented from being damaged without applying an excessive force to the display portion 982. Therefore, a highly reliable electronic device can be realized.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

DESCRIPTION OF SYMBOLS 10 Display apparatus 11 Board | substrate 12 Board | substrate 13 Antireflection layer 13a Dielectric layer 13b Dielectric layer 13c Antiglare pattern 13d Film 20 Layer 21 Element layer 21a FET layer 21b Layer 21c Layer 22 Substrate 23 Light diffusing plate 24a Polarizing plate 24b Polarizing plate 25 Input Device 26 Adhesive layer 30 Drive circuit 30a Drive circuit 30b Drive circuit 31 FPC
31B Display element 31G Display element 32 FPC
32B display element 32G display element 32R display element 33a wiring 33b wiring 33c wiring 33d wiring 35 liquid crystal element 35tr light 36 pixel circuit 40 pixel array 45 pixel unit 46 pixel 46B display element 46G display element 46R display element 46W display element 47 pixel 47B display element 47G display element 47R display element 55r light 55t light 55tr light 100A display apparatus 100B display apparatus 100C display apparatus 101 area 102 area 103 substrate 104 substrate 105 liquid crystal element 105CE electrode 105LC liquid crystal layer 105PE electrode 106 insulating film 108 liquid crystal element 108CE electrode 108LC liquid crystal layer 108PE Electrode 110 Element layer 111 Transistor 112 Transistor 114 Opening 116 Electrode 118 Opening 120 Polarizing plate 122 Light emitting device 122E Edgelight 1 22G light guide plate 122R part 124 structure 124R reflective film 126 structure 128 light diffusion plate 130 input device 132 polarizing plate 134 insulating layer 136 colored layer 138 insulating layer 140 colored layer 141 adhesive layer 142 resin layer 410 pixel 501B insulating film 510 display panel 511 Substrate 512 Substrate 514 Display unit 516 Circuit 518 Wiring 520 IC
522 FPC
524 Electrode 526 Opening 550 Liquid crystal element 560 Substrate 570 Liquid crystal element 571 Insulating film 572 Insulating film 575 Proximity sensor 576 Opening 723 Electrode 724a Electrode 724b Electrode 726 Insulating layer 727 Insulating layer 728 Insulating layer 729 Insulating layer 741 Insulating layer 742 Semiconductor layer 744a Electrode 744b Electrode 746 Electrode 755 Impurity 771 Substrate 772 Insulating layer 800 Display device 801 Display portion 810 Transistor 811 Transistor 820 Transistor 821 Transistor 825 Transistor 830 Transistor 831 Transistor 840 Transistor 841 Transistor 842 Transistor 843 Transistor 844 Transistor 845 Transistor 846 Transistor 847 Transistor 850 Pixel 851 Opening 860 Liquid crystal element 860b Liquid crystal element 8 0g Liquid crystal element 860r Liquid crystal element 861 Electrode 870 Liquid crystal element 901 Case 901b Case 902 Display portion 903 Display portion 904 Sensor 911 Case 912 Display portion 919 Camera 920 Electronic device 921 Case 921a Case 921b Case 922 Display portion 923 Hinge 931 Case 932 Display unit 933 Wristband 935 Button 936 Crown 939 Camera 940 Electronic device 941a Case 941b Case 942 Display unit 943 Hinge 944a Operation button 944b Operation button 945 Cartridge 951 Case 952 Display unit 953 Operation button 954 External connection port 955 Speaker 956 Microphone 957 Camera 961 Case 962 Shutter button 963 Microphone 965 Display unit 967 Speaker 971 Case 973 Display unit 974 Operation key 975 Speaker 976 Communication Connection terminal 977 the optical sensor 980 the electronic device 981a housing 981b housing 982 display unit 983 hinge 6000 display module 6001 top cover 6002 lower cover 6005 FPC
6006 Display panel 6009 Frame 6010 Printed circuit board 6011 Battery 6015 Light emitting unit 6016 Light receiving unit 6017a Light guiding unit 6017b Light guiding unit 6018 Light

Claims (10)

A display device having a first substrate, a second substrate, a first display element, a second display element, an input device, and a drive circuit,
The first substrate and the second substrate have regions overlapping each other;
The first display element and the second display element are provided between a first surface of the first substrate and a first surface of the second substrate,
The first display element has a function of reflecting visible light,
The second display element has a function of transmitting visible light,
The input device is provided between the first surface of the second substrate and the first display element and the second display element.
An antireflection layer is provided on a second surface opposite to the first surface of the second substrate;
The driving circuit is provided on a first surface of the first substrate;
The display device in which the input device and the drive circuit are electrically connected through flexible wiring. In claim 1,
The display device in which the first display element and the second display element are provided in the same pixel unit. In claim 1 or 2,
The display device having a function of driving the first display element, the second display element, and the input device. In any one of Claims 1 thru | or 3,
A display device in which the antireflection layer is provided on a first surface and a second surface of the second substrate. In any one of Claims 1 thru | or 4,
The display device, wherein the antireflection layer is a dielectric layer. In any one of Claims 1 thru | or 4,
The antireflection layer is a display device having an antiglare pattern. In any one of Claims 1 thru | or 6,
The input device includes a wiring having a first layer provided on a first surface of the second substrate and a second layer provided in contact with the first layer;
The display device in which the first layer has a visible light reflectance lower than that of the second layer. In any one of Claims 1 thru | or 7,
A display device in which a light diffusion plate and a polarizing plate are provided between the first display element, the second display element, and the input device. In any one of Claims 1 thru | or 8,
The display device in which the first display element and the second display element are each electrically connected to a transistor including a metal oxide in a semiconductor layer in which a channel is formed. A display device according to any one of claims 1 to 9,
An electronic apparatus including an input device at a position overlapping the display unit.