JP2003157026A - Display device and driving method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of improving the yield and reducing the cost at the time of manufacture, by preventing the circuit configuration from becoming complicated when forming an optical modulation element and a light emitting element within one pixel. SOLUTION: Within a display pixel 10, a reflecting area where a liquid crystal element 20 performs displaying by letting the area reflect external light and a transmission area 12 where an organic EL light emitting element 40, are provided together. The display device is provided with a pair of non- conductive substrates faced to each other, and both of the liquid crystal element 20 and organic EL light emitting element 40 are arranged between a pair of the non-conductive substrates. The source bus lines 2a, etc., and gate bus lines 3, etc., for driving the display pixels 10 arranged in a matrix form by the liquid crystal display element 20 and the organic EL light emitting element 40 are shared with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-light emitting display device such as a liquid crystal display device and a display device such as a light emitting display device using an organic EL light emitting element. More specifically, the present invention relates to a drive circuit of a display device in which a non-light emitting display area and a light emitting display area are provided in a display area.

[0002]

2. Description of the Related Art In recent years, portable information terminals (PDA: Personal Data Assistant) and the like have become widespread, including mobile phones. Along with this, the development of displays for displaying information mounted on these terminals has become very active in recent years.

The above display is roughly classified into a non-light emitting display device and a light emitting display device. The former is to display by modulating light from an external light source such as sunlight, room light, a backlight or a front light by a light modulator.
A liquid crystal display element is known as a typical example. On the other hand, the latter does not require an external light source and the light-emitting element emits light by itself to perform display.
L (Electro Luminescence) has received a great deal of attention. Hereinafter, these display devices will be described in more detail.

First, in a transmissive liquid crystal display device which is a non-emissive display device using an external light source, since a backlight is used as a light source, power consumption is increased and the shape is enlarged, which leaves a problem for portable use. Therefore, in order to suppress the power consumption, which is one of the above problems, the lower electrode of the liquid crystal layer is formed of a metal such as aluminum that reflects light, and thus outside light such as sunlight or an interior light is used as a light source. A reflective liquid crystal display device has been developed. However, this reflective liquid crystal display device is difficult to use in a dark place because it utilizes outside light.

In order to solve such a problem, the lower electrode of the liquid crystal layer is formed by a half mirror so that reflective display is performed without using a backlight in a bright environment, and the backlight is turned on in a dark place to transmit the light. A transflective display device for displaying has been developed. However, in the above-mentioned semi-transmissive display device, since the characteristics of the light-reflecting portion and the light-transmitting portion are contradictory to each other, the light utilization efficiency is low and the decisive improvement for power consumption reduction has not been achieved.

In order to solve such a problem, the inventors of the present invention can use the backlight as a reflective type without using a backlight in a bright environment, and can use the backlight as a transmissive type in a dark place. A liquid crystal display device was devised (see Japanese Patent Application Laid-Open No. 11-101992 [publication date: April 13, 1999]). This liquid crystal display device is different from a conventional liquid crystal display device that uses a reflector having a thin film thickness and semi-transparency, and each display pixel in the liquid crystal display device has two regions, a reflective region and a transmissive region. Is divided into That is, in the liquid crystal display device described above, the reflective electrode is formed as one area of each display pixel to form a reflective area, while the transmissive electrode is formed in the other area of each display pixel to form a transmissive area. Also,
The thickness of the liquid crystal layer in the reflective region is different from the thickness of the liquid crystal layer in the transmissive region. This makes it possible to achieve optimum brightness in each of the reflective area and the transmissive area.

However, in the above-mentioned pixel division type liquid crystal display device, while backlight light is applied to the entire area of each pixel from the rear side, this backlight light is utilized only in the transmissive area of each pixel. Is. Therefore, there is a problem that the utilization efficiency of the backlight light is low.
In particular, when the area ratio of the reflective electrode is high, the transmissive area inevitably becomes narrow, so that the utilization efficiency of the backlight light becomes low.

Therefore, as a method for improving the utilization efficiency of the backlight for the above-mentioned pixel division type liquid crystal display device, for example, Japanese Unexamined Patent Publication No. 2001-66593 [publication date: March 16, 2001]. There is a pixel division type liquid crystal display device disclosed in Jpn. This liquid crystal display device 1
In 00, as shown in FIG. 10, first, the liquid crystal panel 10
The pixel division type liquid crystal display device is obtained by providing the transmissive openings 104 ... In a part of the reflective electrode 103 arranged in each pixel 102 in FIG. Further, in the liquid crystal display device 100, the organic EL element 110 is used as a backlight.
While using a light emitting element consisting of
The 0 light emitting portions 111 ... Are not arranged in the entire area of each pixel 102, but are arranged only in the area corresponding to the transmission openings 104. This makes the patterned organic E
Since the L element is combined as a backlight, the light utilization efficiency can be improved and the power consumption can be reduced.

On the other hand, a display device using the above-mentioned organic EL light-emitting element, which is a typical light-emitting display device, has a feature of being thin and lightweight, and since it is a light-emitting element, it does not require a backlight like a liquid crystal display device and is in a dark environment. However, it can be used, and since almost all of the emitted light is used for display, the light utilization efficiency is high. However, a display device using this organic EL light emitting element needs to always emit light, and it is necessary to increase the light emission amount to improve the display quality especially in a bright environment, and thus it is difficult to reduce the power consumption. It was

[0010]

As described above, the liquid crystal display device and the organic EL display device have characteristics of thinness and lightness, respectively, and in a bright place, the reflection type liquid crystal display device is effective for power consumption. In a dark place, the organic EL display device is effective in terms of light utilization efficiency and shape. Therefore, the liquid crystal display element and the organic E are formed on one substrate.
By forming the L display element, it is possible to make up for each defect and perform optimum display under various environments.

However, in the above display device,
If the liquid crystal display element and the organic EL display element are simply formed on one substrate, the wiring and drive circuit in the substrate become complicated, and the yield and the cost at the time of manufacturing become a problem.

The present invention has been made in view of the above conventional problems, and an object thereof is to prevent the circuit configuration from becoming complicated when two display elements are formed in a display area. An object of the present invention is to provide a display device and a driving method thereof that can reduce the yield and the cost during manufacturing.

[0013]

In order to solve the above-mentioned problems, the display device of the present invention has a first display area for displaying by reflecting external light by the first electro-optical element in the display area. , A second display area for displaying by the second electro-optical element is provided side by side, and a first display area facing each other.
A substrate and a second substrate are provided, and the first electro-optical element and the second electro-optical element are both provided between the first substrate and the second substrate and arranged in a matrix. It is characterized in that each data signal line and each scanning signal line for driving the respective display regions by the first electro-optical element and the second electro-optical element are shared with each other.

According to the above invention, the first electro-optical element and the second electro-optical element are both the first substrate and the second electro-optical element.
Since it is provided between the display device and the substrate, the thickness of the display device can be reduced.

By the way, in the case where the first electro-optical element and the second electro-optical element are provided side by side in each display area, generally, the drive circuit for the first electro-optical element is the drive circuit for the first electro-optical element. Both the second electro-optical element drive circuit is required, and it is expected that the circuit configuration will be complicated.

However, according to the present invention, each data signal line and each scanning signal line for driving the respective display areas arranged in a matrix by the first electro-optical element and the second electro-optical element. Are shared with each other. Therefore,
The first electro-optical element can be driven by the data signal line and the scanning signal line for driving the first electro-optical element. This also means that each driver such as the data driver and the gate driver is shared. As a result,
1st without increasing the number of data signal lines and scanning signal lines
Each display of the electro-optical element and the second electro-optical element can be performed.

Therefore, when the two display elements are formed in the display area, it is possible to prevent the circuit configuration from becoming complicated,
It is possible to provide a display device capable of reducing the yield and the cost during manufacturing.

In order to solve the above-mentioned problems, the display device of the present invention includes, in the display area, a first display area including a non-light emitting display element in which a light modulation element reflects external light to perform display.
The light-emitting element is directly provided with a second display area formed of a light-emitting display element that directly modulates and displays, and a first substrate and a second substrate facing each other are provided. Each of them is provided between the first substrate and the second substrate, and each data signal line and each data signal line for driving the respective display regions arranged in a matrix by the light modulation element and the light emitting element. The scanning signal lines are commonly used.

According to the above invention, since the light modulation element and the light emitting element are both provided between the first substrate and the second substrate, the thickness of the display device can be reduced.

Further, since the light emitting element emits light toward the front to directly display, the light emitting element is not used as a backlight or a front light as in the conventional case. Therefore, the utilization efficiency of light can be improved.

By the way, when an optical modulator and a light emitting element are provided side by side in each display area, generally, both the optical modulator drive circuit and the light emitting element drive circuit are required as the drive circuits. Therefore, it is expected that the circuit configuration will be complicated.

However, in the present invention, the respective data signal lines and the respective scanning signal lines for driving the respective display areas arranged in a matrix by the light modulating element and the light emitting element are shared with each other. Therefore, the light emitting element can be driven by the data signal line and the scanning signal line for driving the light modulation element. This also means that each driver such as the data driver and the gate driver is shared. As a result, each display of the light modulation element and the light emitting element can be performed without increasing the number of data signal lines and scanning signal lines.

Therefore, when the two display elements are formed in the display area, the circuit structure is prevented from becoming complicated,
It is possible to provide a display device capable of reducing the yield and the cost during manufacturing.

In order to solve the above-mentioned problems, the display device of the present invention includes, in the display area, a first display area including a non-light emitting display element in which a light modulation element reflects external light to perform display.
The light-emitting element is directly provided with a second display area formed of a light-emitting display element that directly modulates and displays, and a first substrate and a second substrate facing each other are provided. Each is provided between the first substrate and the second substrate, and each data signal line and each scanning signal line for driving the respective display regions arranged in a matrix by the light modulator. It is characterized in that the light emitting element can be driven by applying a drive signal to.

According to the above invention, since the light modulation element and the light emitting element are both provided between the first substrate and the second substrate, the thickness of the display device can be reduced.

Further, since the light emitting element emits light toward the front to directly display, the light emitting element is not used as a backlight or a front light as in the conventional case. Therefore, the utilization efficiency of light can be improved.

By the way, when an optical modulation element and a light emitting element are provided side by side for each display area, generally, both the optical modulation element drive circuit and the light emitting element drive circuit are required as the drive circuits. Therefore, it is expected that the circuit configuration will be complicated.

However, in the present invention, by applying a drive signal to each data signal line and each scanning signal line for driving the respective display areas arranged in a matrix by the light modulation element, the light emitting element is obtained. Can be driven. Therefore, the light emitting element can be driven by the data signal line and the scanning signal line for driving the light modulation element. This also means that each driver such as the data driver and the gate driver is shared. As a result, each display of the light modulation element and the light emitting element can be performed without increasing the number of data signal lines and scanning signal lines.

Therefore, when the two display elements are formed in the display area, the circuit structure is prevented from becoming complicated,
It is possible to provide a display device capable of reducing the yield and the cost during manufacturing.

The display device of the present invention is the display device described above, further comprising voltage-current conversion means for converting a voltage into a current for driving the light emitting element, and an optical modulator which is a switching element for driving the optical modulator. The drain electrode of the device transistor is connected to the voltage-current conversion means.

That is, the light emitting element is generally driven by an electric current. On the other hand, a voltage is generally applied to the drain electrode of the light modulation element transistor, which is a switching element that drives the light modulation element.

Therefore, in the present invention, by connecting the drain electrode to the voltage-current converting means and converting the voltage into the current by the voltage-current converting means, the light emitting element can be surely caused to emit light.

According to the display device of the present invention, in the display device described above, the voltage-current conversion means comprises a light emitting element transistor, and the threshold voltage of the light emitting element transistor for driving the light emitting element is a light modulation element. It is characterized in that it is larger than the drive voltage of.

According to the above invention, the voltage-current conversion means is composed of a light emitting element transistor. The threshold voltage of the light emitting element transistor for driving the light emitting element is higher than the drive voltage of the light modulation element. Therefore,
When driving the light modulation element, a drive voltage lower than the threshold voltage of the light emitting element transistor is applied to the data line signal, while when driving the light emitting element, a drive voltage higher than the threshold voltage of the light emitting element transistor is applied to the data line signal. By applying a signal, the light emitting element can also emit light.

That is, in the present invention, by controlling the threshold voltage of the light emitting element transistor of the light emitting element,
The reflective display and the light emitting display can be easily selected. As a result, it is possible to reliably prevent the circuit configuration from becoming complicated and drive the light modulation element and the light emitting element with one scanning signal line and one data signal line.

According to the display device of the present invention, in the display device described above, the voltage-current converting means comprises a light emitting element transistor, and the light emitting element transistor is turned on.
The operation region and the ON operation region of the light modulation element transistor for driving the light modulation element are characterized by being divided by the threshold voltage.

According to the above invention, the voltage-current conversion means is composed of a light emitting element transistor. Further, the ON operation region of the light emitting element transistor and the ON operation region of the light modulation element transistor for driving the light modulation element are distributed by the threshold voltage. Therefore, when driving the light modulation element, a driving voltage lower than the threshold voltage of the light emitting element transistor is applied to the data line signal, while driving the light emitting element applies a driving voltage higher than the threshold voltage of the light emitting element transistor. By applying the data line signal, the light emitting element can also emit light.

As a result, it is possible to surely prevent the circuit structure from becoming complicated and drive the light modulation element and the light emitting element by one scanning signal line and one data signal line.

The display device of the present invention is characterized in that, in the display device described above, the characteristic of the light modulation element is normally white.

That is, in the above-mentioned invention, when the light emitting element is driven, the light modulation element is also driven. Therefore, since both are driven, if the display state when the light modulation element is driven is white display, the contrast in one pixel is reduced by the white display of the light modulation element and the light emission display of the light emitting element.

In this respect, in the present invention, the characteristic of the light modulation element is normally white. This means that when no voltage is applied to the light modulation element, the first display area displays white, while when voltage is applied to the light modulation element, the reflectance becomes zero and the first display area is black. Will be displayed. Further, black display is performed as the voltage applied from the data signal line to the light modulator increases.

Therefore, when the light emitting element is driven, as described above, the light modulation element is in a driven state, and the display is black.

As a result, the second display area of the light emitting element
Since black is displayed around the display area, it is possible to prevent a decrease in contrast due to driving the light emitting element to emit light.

The display device of the present invention is characterized in that, in the display device described above, the light modulation element is a liquid crystal display element.

According to the above invention, the light modulation element is a liquid crystal display element. Therefore, it is possible to easily provide the display device which can prevent the circuit configuration from becoming complicated when the two display elements are formed in the display region and can reduce the yield and the cost at the time of manufacturing.

The display device of the present invention is the display device described above, wherein a pixel electrode having external light reflectivity is provided, and a counter electrode facing the pixel electrode is provided over the entire display region on the second substrate side. In addition, when the display is performed by the light modulation element, it is driven to the potential of the counter electrode, and when the display is performed by the light emitting element, it is driven to the potential of the reference electrode.

That is, in view of the characteristics of the liquid crystal display element, the liquid crystal display element needs to be driven in reverse with respect to the potential of the counter electrode, that is, AC drive. On the other hand, as described above, the light emitting element may be non-inversion driven by current, that is, DC driven.

In this respect, according to the above invention, when the display is performed by the light modulation element, it is driven to the potential of the counter electrode, while when the display is performed by the light emitting element, it is driven to the potential of the reference electrode. .

Therefore, when the liquid crystal display element is used as the light modulation element, the light modulation element and the light emitting element can be driven reliably and appropriately.

The display device of the present invention is the display device described above, in which the light emitting element is provided on the rear side of the pixel electrode having external light reflectivity, and the light emitting element is directed toward the front display surface side. When the light is emitted by itself, the display is performed only in the second display area, and the light is not transmitted in the first display area where the pixel electrode exists.

According to the above invention, the light emitting element is provided on the rear side of the pixel electrode having external light reflectivity.
When the light emitting element itself emits light toward the front display surface side, display is performed only in the second display area, and light is not transmitted in the first display area where the pixel electrode exists.

Therefore, when the light emitting element is driven, the pixel electrode of the light modulation element functions as a black matrix. As a result, the contrast of the light emitting element can be maintained.

Further, the display device driving method of the present invention uses the display device described above to divide one field, which is a unit time of a video signal in each display region, into a plurality of fields, and to divide the light field in each divided period. It is characterized by turning on / off the modulation element or the light emitting element.

According to the above invention, when the above display device is driven, one field is divided into a plurality of fields, and the light modulation element or the light emitting element is turned on / off for each divided period, so that one field is generated. It is possible to control the total ON time of the light modulation element or the light emitting element in, and further to increase the types of lighting patterns and to efficiently drive them.

In this way, by controlling the ON time of the light modulation element or the light emitting element temporally, it is possible to display the gradation of the video signal.

Therefore, it is possible to prevent the circuit configuration from becoming complicated when two display elements are formed in the display area.
It is possible to provide a driving method of a display device, which can reduce the yield and cost at the time of manufacturing and can efficiently perform gradation display.

Further, in the display device driving method of the present invention, in the display device driving method described above, when one field, which is a unit time of a video signal in each of the display regions, is divided into a plurality of divisions. The width is 1: 2 ¹ : 2 ² : ...: 2
It is characterized in that it is divided into ⁿ (n is a positive integer) intervals.

According to the above invention, when one field is divided into a plurality of pieces, each division width is 1 (= 2 ⁰ ): 2 ¹ :
It is divided so as to have an interval of 2 ² : ...: 2 ⁿ (n is a positive integer).

As a result, according to this division method, 2 ⁿ gray scales can be displayed, and the number of scanning line signal selections can be reduced to increase the number of gray scales.

[0060]

BEST MODE FOR CARRYING OUT THE INVENTION [Embodiment 1] An embodiment of the present invention will be described with reference to FIGS. 1 to 8.
It is as follows.

As shown in FIG. 2, the display device 1 of this embodiment has a plurality of source bus lines 2a as data signal lines provided in the vertical direction and a plurality of scanning signal lines provided in the horizontal direction. Each of the display pixels 10 as a display area is formed in a matrix by the gate bus lines 3.

The display pixel 10 has, in the present embodiment,
It is divided into a reflective region 11 as a first display region having reflectivity and a transmissive region 12 as a second display region having transmissivity. That is, as shown in FIG. 3, a pixel electrode 25 made of a metal such as aluminum (Al), which constitutes a reflective liquid crystal display element 20 as a light modulation element, is formed in the reflective area 11. The external light 4 is reflected by the pixel electrode 25.

On the other hand, a rectangular opening 25a is formed in the center of the pixel electrode 25, and this opening 25a serves as the transmission region 12. Opening 25 of pixel electrode 25
The transparent insulating layer 2 is provided below a, that is, behind the pixel electrode 25.
4 through the organic EL (Electro Lumines
The organic EL light emitting element 40 emits the display light 5 by itself to directly perform display. That is, in the present embodiment, the organic EL light emitting element 4 is not used as a backlight or a front light as in the related art, but the organic EL light emitting element 4 is used.
Since 0 directly performs display, the display device 1 according to the present embodiment includes an organic EL device including the reflective liquid crystal display device including the liquid crystal display element 20 and the organic EL light emitting element 40.
It can be said that the display device is integrated with the display device.

The display device 1 is, as shown in FIG.
A thin film transistor element for liquid crystal (hereinafter, referred to as "TFT for liquid crystal (Thin Film Transistor) as a transistor for light modulation element is provided on an insulating substrate 21 as a first substrate such as a glass substrate.
r) element ”. ) 22, whereby each display pixel 10 ... Is actively driven. As shown in FIG. 2, the liquid crystal TFT element 22 is connected to the gate bus lines 3 and the source bus lines 2a and functions as a switching element for applying a voltage to the pixel electrode 25 through the drain electrode 22a. . Although the liquid crystal TFT element 22 is used as the switching element in the present embodiment, the present invention is not limited to this. For example, a liquid crystal MIM (Metal In
It may be a sulator metal) element.

On the other hand, the drain electrode 22a of the liquid crystal display element 20 is an E as a voltage / current converting means for driving the organic EL light emitting element 40 and a light emitting element transistor.
It is connected to a gate electrode 42a of an L thin film transistor element (hereinafter referred to as “EL TFT element”) 42. Further, on the source side of the EL TFT element 42,
The current supply line 2b is connected, and when the EL TFT element 42 is turned on, the organic EL of the organic EL light emitting element 40 is passed through the current supply line 2b and the drain electrode 42a of the EL TFT element 42 by the supply voltage Vdd.
A drive current flows through the layer 41, and the organic EL layer 41 emits light. The liquid crystal display element 20 and the organic EL
The drive circuit of the light emitting element 40 will be described in detail later.

The structure of the display device 1 will be described below in more detail with reference to FIGS. 2 and 3 together with the description of the manufacturing method.

First, as shown in FIG. 3, a liquid crystal TFT element 22 is formed on an insulating substrate 21 such as a glass substrate.
At this time, the EL TFT element 42 is also formed at the same time.
Next, after the flattening film 23 is formed with a thickness of 2 μm, for example, using a photosensitive acrylic resin, the organic EL light emitting device 40 is formed.
The reflective anode 43 constituting the above is formed of chromium (Cr) with a thickness of 2000 Å by a sputtering method. Further, the insulating layer 44 is formed by forming silicon dioxide (SiO ₂ ) to a thickness of 2000 Å by a sputtering method and performing etching so as to have a predetermined shape.

Subsequently, an organic E as a light emitting layer is formed by a vapor deposition method.
The L layer 41 is formed. The organic EL layer 41 is formed by mask evaporation using red, green, and blue light emitting materials corresponding to the respective display pixels 10. Next, in order to efficiently inject electrons into the organic EL layer 41, an alloy (not shown) of magnesium and silver having a thickness of 100 Å is formed by a vapor deposition method, and then a cathode 45 having transparency is formed by an indium-zinc oxide by a sputtering method. (IZO) is formed to a thickness of 2000Å. Then, the transparent insulating layer 2 is formed by the sputtering method.
After forming tantalum pentoxide (Ta ₂ O ₅ ) with a thickness of 7,000 Å as 4, liquid crystal layer 2 constituting liquid crystal display element 20 is formed.
A pixel electrode 25 having reflectivity for driving 6 is formed of aluminum (Al).

On the other hand, the color filter layer 2 is formed on the transparent insulating substrate 29 as the second substrate such as the other glass substrate.
8 and indium-tin oxide (ITO: Indium Tin O
The counter electrode 27 made of xide) is sequentially formed.

Next, an unillustrated alignment film (trade name "JALS204 (manufactured by Japan Synthetic Rubber Co., Ltd.)" having a property of vertically aligning liquid crystal molecules with respect to the insulating substrate 29 is applied by spin coating and then baked. To form.

Next, the molded substrate on the side of the insulating substrate 21 is irradiated with ultraviolet light through a mask (not shown) having an opening so as to expose only a region other than the region where the organic EL light emitting element 40 is formed. On the other hand, when the molded substrate on the insulating substrate 29 side is also bonded to the insulating substrate 21,
The region other than the portion facing the organic EL light emitting element 40 is irradiated with ultraviolet light. After rubbing these two molded substrates to uniaxially align the alignment film (not shown),
Dielectric anisotropy is positive after bonding with sealing resin
A liquid crystal material (manufactured by Merck & Co., Inc.) having n of 0.06 is injected to prepare the liquid crystal display element 20. Further, the display device 1 is completed by sequentially adhering the retardation plate 31 and the polarizing plate 32 to the surface of the insulating substrate 29. The phase difference plate 31
The phase difference of was 1/4 with respect to the light of λ = 550 nm.

Next, a drive circuit for driving the display device 1 having the above structure will be described.

As shown in FIG. 4, in the display device 1, the source driver 6 for sequentially sending the data line signals is connected to the source bus lines 2a ... And the gate driver 7 for selecting the display pixels 10 ... It is connected to the gate bus line 3 ... The display circuit in one display pixel 10 is composed of a liquid crystal display element 20 which is a light modulation element and an organic EL light emitting element 40 which is a light emitting element.

The liquid crystal display element 20 and the organic EL light emitting element 40 are arranged in a matrix in the display area of the display device 1, and the counter electrode 2 of the liquid crystal display element 20 is arranged.
7, the current supply line 2b of the EL TFT element 42, and the cathode 45 as the reference electrode of the organic EL light emitting element 40,
The liquid crystal display element 20 and the organic EL light emitting element 40 are commonly connected.

As shown in FIG. 1, the liquid crystal TFT element 2 has a circuit configuration for one pixel in the display device 1 having the above configuration.
The two gate electrodes are connected to the gate bus line 3, and the source bus line 2a is connected to the source electrode of the liquid crystal TFT element 22. Further, the drain electrode 22a of the liquid crystal TFT element 22 is connected to the liquid crystal display element 20, the liquid crystal auxiliary capacitance 35, and the gate electrode of the EL TFT element 42. The source electrode of the EL TFT element 42 is connected to the current supply line 2b, and the drain electrode of the EL TFT element 42 is connected to the anode 43 of the organic EL light emitting element 40. In the above configuration, the organic EL light emitting device 40
Is provided on the drain side of the EL TFT element 42, but is not necessarily limited to this, and may be provided on the source side of the organic EL light emitting element 40 as shown in FIG. 5, for example.

In the drive circuit of the display device 1 thus constructed, the liquid crystal TFT elements 22 are driven by the scanning line signals from the gate bus lines 3 ...
Change the signal of. Then, the data line signal is T for EL
When it is smaller than the EL threshold voltage Vth (OLED) of the FT element 42, the organic EL light emitting element 40 does not emit light and only the liquid crystal display element 20 reacts, and the reflective display performs from bright display to dark display. In addition, the data line signal is an EL TFT
When the voltage is higher than the EL threshold voltage Vth (OLED) of the element 42, the liquid crystal display element 20 is performing dark display and the EL TFT element 42 is caused by the data line signal.
The drain current of the organic EL light emitting element 40 is changed, and the light emission amount of the organic EL light emitting element 40 is adjusted to perform the light emitting display. The amount of light emitted from the organic EL light emitting element 40 can be adjusted by adjusting the supply voltage Vdd.

The driving method of the display device 1 will be described in detail.

As shown in FIG. 6, the gate bus lines 3 ...
The scanning line signal Vg from the above makes the liquid crystal TFT element 22 in the ON state by increasing the voltage at the time of selection, and turns off the liquid crystal TFT element 22 by making the voltage low at the time of non-selection.
Put in a state. Further, the data line signal Vs from the source bus lines 2a ... Is a COM signal Vcom in the reflective display.
Inversion driving is performed on the COM signal Vcom
The signal of the difference between and adjusts the amount of reflected light for display.

At this time, since the data line signal Vs from the source bus lines 2a ... Does not exceed the EL threshold voltage Vth (OLED) of the EL TFT element 42, the organic E
No current flows through the L light emitting element 40 and no light emission display is performed. On the other hand, the data line signal Vs from the source bus lines 2a ... Is the EL threshold voltage Vth of the EL TFT element 42.
When (OLED) is exceeded, a current flows through the organic EL light emitting element 40 to perform light emission display.

In the case of the light emitting display, the data line signal Vs from the source bus lines 2a ... Is not inverted because the amount of light emission is controlled by the signal value for GND.

Further, in the present embodiment, the liquid crystal display element 2
0 uses normally white type liquid crystal. Therefore, if the difference between the COM signal Vcom and the data line signal Vs from the source bus lines 2a ... Is large, dark display is performed, so that the reflective display portion does not reflect the external light 4 and can perform light emitting display. it can.

Further, in the present embodiment, the liquid crystal display element 2
In order to prevent the burn-in of 0, the COM signal Vcom serving as the counter electrode 27 prevents the burn-in by alternating-current driving the liquid crystal display element 20 even during the light emission display.

On the other hand, as shown in FIG. 7, the data line signal V
In a range in which s is smaller than the EL threshold voltage Vth (OLED), the external light 4 is used to perform the reflective display by the liquid crystal display element 20. Further, in this range, by using the normally white liquid crystal, the bright display with a large reflection amount is changed to the dark display with a small reflection amount.
Since 2 is equal to or lower than the EL threshold voltage Vth (OLED), the organic EL light emitting element 40 does not emit light.

On the other hand, the data line signal Vs becomes large and EL
Threshold voltage Vth (OLED) of the TFT element 42 for EL
When it becomes larger than this, a current flows through the organic EL light emitting element 40 to provide a light emitting display, and the light emission amount changes according to the characteristics of the EL TFT element 42 by the data line signal Vs. In this case, since the liquid crystal display element 20 is displaying dark,
The display is performed only by the light emission of the organic EL light emitting element 40 without reflection by.

In the present embodiment, one EL TFT element 42 is used as the voltage / current converting means, but the present invention is not limited to this. That is, as shown in FIG. 8, in order to suppress the in-plane variation of the display device 1, two or more elements may be used, and the threshold value control of the operating voltage and the light emission amount control by the data line signal Vs from the source bus lines 2a. Any configuration is possible.

As described above, in the display device 1 of the present embodiment, since the liquid crystal display element 20 and the organic EL light emitting element 40 are both provided between the insulating substrate 21 and the insulating substrate 29, the display The thickness of the device 1 can be reduced.

Further, since the organic EL light emitting element 40 emits light by itself toward the front to directly display, as in the conventional case,
The organic EL light emitting device 40 is not used as a backlight or a front light. Therefore, the utilization efficiency of light can be improved.

By the way, when the liquid crystal display element 20 and the organic EL light emitting element 40 are provided side by side for each display pixel 10, generally, as a driving circuit thereof, a liquid crystal display element drive circuit and an organic EL light emitting element are provided. Both the drive circuit is required, and the circuit configuration is expected to be complicated.

However, in the present embodiment, the display pixels 10 ... Arranged in a matrix are replaced by the liquid crystal display element 20.
The source bus lines 2a and the gate bus lines 3 for driving the organic EL light emitting element 40 are shared with each other. Therefore, the source bus lines 2a ... And the gate bus lines 3 for driving the liquid crystal display element 20.
The organic EL light emitting device 40 can be driven by.
This also means that the drivers such as the source driver 6 and the gate driver 7 are shared. As a result, each display of the liquid crystal display element 20 and the organic EL light emitting element 40 can be performed without increasing the source bus lines 2a ... And the gate bus lines 3 ...

Therefore, the liquid crystal display element 20 and the organic E
It is possible to provide the display device 1 which can prevent the circuit configuration from becoming complicated when the L light emitting element 40 is formed in the display pixel 10 and can reduce the yield and the cost during manufacturing.

Further, in the display device 1 of the present embodiment, the drive signal is applied to the source bus lines 2a and the gate bus lines 3 to the liquid crystal display element 20 to drive the organic EL light emitting element 40. You can Therefore, the organic EL light emitting device 40 can be driven by the source bus lines 2a and the gate bus lines 3 for driving the liquid crystal display device 20. This also means that the drivers such as the source driver 6 and the gate driver 7 are shared. As a result, the source bus line 2a ...
The liquid crystal display element 20 and the organic EL light emitting element 40 can be displayed without increasing the number of gate bus lines 3 ...

Therefore, the liquid crystal display element 20 and the organic E
It is possible to provide the display device 1 that can prevent the circuit configuration from becoming complicated when the L light emitting element 40 is formed in one display pixel 10 and can reduce the yield and the cost during manufacturing.

By the way, the organic EL light emitting device 40 is generally driven by an electric current. On the other hand, the liquid crystal display element 2
A voltage is generally applied to the drain electrode 22a of the liquid crystal TFT element 22 which is a switching element for driving 0.

Therefore, in this embodiment, the liquid crystal TFT is used.
The drain electrode 22a of the element 22 is connected to the EL TFT element 42.
The organic EL light emitting element 40 can be surely made to emit light by connecting to the EL element and converting the voltage into a current by the EL TFT element 42.

Further, in the display device 1 of the present embodiment, the voltage / current conversion means is composed of the EL TFT element 42. In addition, a TF for EL for driving the organic EL light emitting device 40
The EL threshold voltage Vth (OLED) of the T element 42 is higher than the drive voltage of the liquid crystal display element 20. Therefore,
When driving the liquid crystal display element 20, a driving voltage lower than the EL threshold voltage Vth (OLED) is applied to the data line signal Vs, while driving the organic EL light emitting element 40 is lower than the EL threshold voltage Vth (OLED). The organic EL light emitting element 40 can also emit light by applying a large drive voltage to the data line signal Vs.

That is, in the present embodiment, by controlling the EL threshold voltage Vth (OLED), it is possible to easily select the reflective display or the light emitting display. As a result,
It is possible to reliably prevent the circuit configuration from becoming complicated and drive the liquid crystal display element 20 and the organic EL light emitting element 40 by one gate bus line 3 ... And source bus line 2a.

In the display device 1 of this embodiment, E
ON operation area of the L TFT element 42 and the liquid crystal display element 20.
The ON operation region of the liquid crystal TFT element 22 for driving the OLED is divided by the EL threshold voltage Vth (OLED). Therefore, when the liquid crystal display element 20 is driven, a drive voltage lower than the EL threshold voltage Vth (OLED) is applied to the data line signal Vs, while
When driving the organic EL light emitting element 40, by applying a drive voltage larger than the EL threshold voltage Vth (OLED) to the data line signal Vs, the organic EL light emitting element 4 is driven.
0 can also emit light.

As a result, the liquid crystal display element 20 and the organic EL light emitting element 40 can be driven by one gate bus line 3 ... And source bus line 2a. it can.

In the present embodiment, the liquid crystal display element 2
The characteristic of 0 is normally white. This means that in the state where no voltage is applied to the liquid crystal display element 20, the reflective region 11 displays white while the liquid crystal display element 2
When a voltage is applied to 0, the reflectance becomes zero and the reflective region 11 displays black. Also, the source bus line 2
The larger the voltage applied from a to the liquid crystal display element 20, the blacker the display. Therefore, the organic EL light emitting element 4
When driving 0, as described above, the liquid crystal display element 2
0 is a driving state, and its display is black.

As a result, black is displayed around the transmissive region 12 which is the display region of the organic EL light emitting element 40, so that it is possible to prevent the contrast from being lowered by driving the organic EL light emitting element 40 to emit light.

Further, in the display device 1 of the present embodiment, the light modulation element is composed of the liquid crystal display element 20. Therefore, by improving the conventional reflective liquid crystal display device, the liquid crystal display device 20 and the organic EL light emitting device 4 can be easily manufactured.
It is possible to provide the display device 1 which can prevent the circuit configuration from becoming complicated when 0s are formed in one display pixel 10 and can reduce the yield and the cost during manufacturing.

Here, due to the characteristics of the liquid crystal TFT element 22,
The liquid crystal display element 20 needs to be inverted-driven, that is, AC-driven with respect to the potential of the counter electrode 27. On the other hand, as described above, the organic EL light emitting element 40 may be non-inverting driven by current, that is, DC driven.

In this respect, in the display device 1 of the present embodiment,
A pixel electrode 25 having external light reflectivity is provided, and a counter electrode 27 facing the pixel electrode 25 is provided on the entire surface of the display pixel 10 on the counter substrate side. Further, when displaying by the liquid crystal display element 20, the organic EL light emitting element 40 is driven while being inverted with respect to the potential of the counter electrode 27.
When displaying by, the potential of the cathode 45, that is, GN
It is driven non-inverted with respect to the D potential.

Therefore, when the liquid crystal display element 20 is used as the light modulation element, the liquid crystal display element 20 and the organic EL light emitting element 40 can be driven reliably and appropriately.

In addition, in the display device 1 of the present embodiment, the organic EL light emitting element 40 has the pixel electrode 2 having the external light reflectivity.
It is provided on the rear side of 5. When the organic EL light emitting element 40 emits light toward the front, display is performed only in the transmissive region 12, and light is not transmitted in the reflective region 11 where the pixel electrode 25 exists.

Therefore, when the organic EL light emitting element 40 is driven, the pixel electrode 25 of the liquid crystal display element 20 serves as a black matrix. Therefore, the contrast of the organic EL light emitting device 40 can be maintained.

In the present embodiment, the reflection type liquid crystal display element 20 is used as the light modulation element, but the present invention is not limited to this, and for example, a mirror or the like is used to change the light reflection amount for display. A display element that can be used may be used. Further, it is possible to use an electrophoretic display, a twist ball display, a reflection display using a fine prism film, a light modulation element such as a digital mirror device.

Further, although the organic EL light emitting element 40 is used as the light emitting element in the present embodiment, the present invention is not limited to this. For example, an inorganic EL light emitting element, an LED (Light Em
It is applicable as long as it is an element such as an itting diode) whose emission luminance is variable. It is also possible to use a light emitting element such as a field emission display (FED) or a plasma display.

Further, in the present embodiment, the driving circuit in the case where the organic EL light emitting element 40 is provided behind the pixel electrode 25 has been described, but the present invention is not limited to this, and the organic EL light emitting element 40 is a liquid crystal. The driver circuit described in this embodiment can be applied to the case where the driver circuit is provided in the same layer as the layer 26.

[Second Embodiment] The following will describe another embodiment of the present invention in reference to FIG. For convenience of description, members having the same functions as the members shown in the drawings of the first embodiment will be designated by the same reference numerals, and the description thereof will be omitted. Further, the various characteristic points described in the first embodiment can be applied to the present embodiment.

As described above, the liquid crystal display device and the organic EL
The display device has characteristics such as thinness and lightness, and the reflective liquid crystal display device is effective for power consumption in a bright place, while the organic EL display device is effective in a dark place because of light utilization efficiency and shape. . Therefore,
By forming a liquid crystal display element and an organic EL display element on one substrate, it is possible to compensate for their respective defects and perform optimum display under various environments.

However, in the above display device 1, if the liquid crystal display element and the organic EL display element are simply formed on one substrate, the wiring and drive circuit in the substrate become complicated, and the yield at the time of manufacturing and Cost etc. becomes a problem.

Therefore, in the display device 1 described above, the drive of the liquid crystal display element 20 and the organic EL light emitting element 40 is performed by adopting the configuration of FIG. 4 in the first embodiment.
Gate bus lines 3 which are signal lines and scanning signal lines ...
, And the source bus lines 2a, which are signal lines and data signal lines, are shared to solve the above problem.

In the present embodiment, a driving method in the driving circuit of the display device 1 different from that of the first embodiment will be described in detail. The drive circuit is the same as that shown in FIG.

First, one field which is a unit time of a video signal in one display pixel 10 is represented as 1T as shown in FIG. 9A.

In this embodiment, as shown in FIGS. 9B and 9C, the scanning line signal Vg from the gate bus lines 3 ...
While turning on the T element 22, the liquid crystal TFT element 22 is turned off by lowering the voltage when not selected.

The scanning line signal Vg is 1 field T
During this period, it is selected multiple times and is in the ON state. Further, the time interval for selecting the scanning line signal Vg is not an equal interval but an interval of a power of 2. That is, in the same figure (b), 1 field T is set to 2 ⁰ : 2 ¹ : 2 ²
It is divided so that As a result, 1 field T
Are intervals of (1/7) T, (2/7) T, and (4/7) T. It should be noted that even if the time intervals are equal, there is no problem in driving, but by setting the intervals to a power of 2, the number of selections of the scanning line signal Vg can be reduced and the number of gradations can be increased. That is, in this way, when one field T is divided into, for example, 2 ⁰ : 2 ¹ : 2 ² and each divided portion is individually turned on, a total lighting time within one field T is considered to be 8 This makes it possible to represent different types of gradation.

In this embodiment, one field T
While the scanning line signal Vg is turned ON three times during this period, eight kinds of gradations are represented, but the number of gradations is not limited to this, and the number of gradations on the display can be further increased by increasing the number of times. Can be increased. That is, generally, when one field T which is a unit time of a video signal is divided into a plurality of pieces, each division width is 1 (= 2 ⁰ ): 2 ¹ :
The division may be performed so as to have an interval of 2 ² : ...: 2 ⁿ (n is a positive integer). As a result, 2 ⁿ gradations can be displayed. In addition, the number of selections of the scanning line signal Vg can be reduced and the number of gradations can be increased.

Specific driving methods of the reflective display and the light emitting display will be described below.

First, in the case of performing the reflection type display, FIG.
As shown in (b), the source bus line 2a shown in FIG.
The data line signal Vs from ... Is inverted and driven with respect to the COM signal Vcom, and the reflected light amount is changed by a binary signal of the COM signal Vcom. Further, the scanning line signal Vg is turned on and off three times, and the amount of reflected light is temporally adjusted to perform display. That is, the amount of reflected light is adjusted by increasing or decreasing the reflection time.

In the present embodiment, the liquid crystal display element 2
Since 0 uses a normally white type liquid crystal, FIG.
The drive signal shown in (b) is in the bright state during the period (4/7) T and the period (1/7) T, while the period (2
In / 7) T, it is in a dark state, which means that both the first field and the second field display the fifth gradation. That is, for example, in the period (2/7) T,
The COM signal Vcom is in the ON state, while the data line signal Vs is in the OFF state. As a result, the liquid crystal display element 2
Since the voltage is applied to 0, the period (2 /
7) At T, it becomes a dark state.

At this time, the data line signal Vs from the source bus lines 2a ... Does not exceed the EL threshold voltage Vth (OLED) of the EL TFT element 42 shown in FIG. No current flows and no light emission is displayed.

On the other hand, when performing the light emission display,
As shown in (c), the data line signal Vs from the source bus lines 2a ... Exceeds the EL threshold voltage Vth (OLED) of the EL TFT element 42, so that the organic E
A current flows through the L light emitting element 40 to perform light emitting display. In addition, the EL threshold voltage Vth (O
If it is smaller than (LED), no light is emitted.

In this embodiment, the scanning line signal Vg is turned on three times during one field T, and the organic EL light emitting element 40 is turned on and off within the scanning line signal Vg three times. Similar to the device 20, display is performed by adjusting the amount of emitted light with time. Specifically, as shown in FIG. 9C, when the period is (4/7) T and (1/7) T, O
While in the N state, OFF during the period (2/7) T
In this state, both the first field and the second field display the fifth gradation.

At the time of light emission display, the ON / OFF of light emission is controlled by a signal to GND, so that CO
The M signal Vcom is constant and the data line signal Vs from the source bus lines 2a ... Is not inverted. Further, in the present embodiment, the liquid crystal display element 20 is
As described above, the normally white type liquid crystal is used. Therefore, since the difference between the COM signal Vcom and the data line signal Vs from the source bus line 2a is always a large value, the liquid crystal is always in a dark display, and the reflective display portion emits light without reflecting the external light 4. Display can be performed.

Further, in the present embodiment, when the light emitting display is performed, the COM signal Vcom is kept constant and the data line signal Vs from the source bus lines 2a ... Is changed. Therefore, when the organic EL light emitting element 40 is turned on,
By turning OFF, the liquid crystal display element 20 is AC-driven with respect to the COM signal Vcom,
Prevents burn-in.

In the present embodiment, one EL TFT element 42 is used as the voltage / current converting means, but the present invention is not limited to this. That is, as shown in FIG. 8, in order to suppress the in-plane variation of the display device 1, two or more elements may be used, and the threshold value of the operating voltage can be controlled by the data line signal Vs from the source bus lines 2a. good.

As described above, in this embodiment, the source bus lines 2a for driving the display pixels 10 arranged in a matrix by the liquid crystal display element 20 and the organic EL light emitting element 40, and The gate bus lines 3 ... Are shared with each other.

In the display device 1 of the present embodiment, the organic EL light emitting element 40 is driven by applying a drive signal to the source bus lines 2a ... And the gate bus line 3 ... To the liquid crystal display element 20. You can Therefore, the organic EL light emitting device 40 can be driven by the source bus lines 2a and the gate bus lines 3 for driving the liquid crystal display device 20. This also means that the drivers such as the source driver 6 and the gate driver 7 are shared. As a result, the source bus line 2a ...
The liquid crystal display element 20 and the organic EL light emitting element 40 can be displayed without increasing the number of gate bus lines 3 ...

In this embodiment, the liquid crystal display element 2
The characteristic of 0 is normally white. This means that in the state where no voltage is applied to the liquid crystal display element 20, the reflective region 11 displays white while the liquid crystal display element 2
When a voltage is applied to 0, the reflectance becomes zero and the reflective region 11 displays black. Also, the source bus line 2
The larger the voltage applied from a to the liquid crystal display element 20, the blacker the display.

Therefore, when the organic EL light emitting element 40 is driven, as described above, the liquid crystal display element 20 is in a driving state, and the display is black.

As a result, black is displayed around the transmissive region 12 which is the display region of the organic EL light emitting element 40, so that it is possible to prevent the contrast from being lowered by driving the organic EL light emitting element 40 to emit light.

Further, in the display device 1 of the present embodiment, the light modulation element is the liquid crystal display element 20. As a result, by forming the liquid crystal display element 20 and the organic EL light emitting element 40 in one display pixel 10, the advantages of the liquid crystal display element 20 are low power consumption and the organic EL light emitting element 4.
It is possible to provide the display device 1 capable of achieving high light utilization efficiency, which is an advantage of 0.

Here, due to the characteristics of the liquid crystal TFT element 22,
The liquid crystal display element 20 needs to be inverted-driven, that is, AC-driven with respect to the potential of the counter electrode 27. On the other hand, as described above, the organic EL light emitting element 40 may be non-inverting driven by current, that is, DC driven.

In this respect, in the display device 1 of the present embodiment,
A pixel electrode 25 having external light reflectivity is provided, and a counter electrode 27 facing the pixel electrode 25 is provided on the entire surface of the display pixel 10 on the counter substrate side. Further, when performing display by the liquid crystal display element 20, the organic EL light emitting element 4 is driven while being inverted with respect to the potential of the counter electrode 27.
When displaying with 0, the potential of the cathode 45, that is, G
It is driven non-inverted with respect to the ND potential.

Therefore, when the liquid crystal display element 20 is used as the light modulation element, the liquid crystal display element 20 and the organic EL light emitting element 40 can be driven reliably and appropriately.

In addition, in the display device 1 of the present embodiment, the organic EL light emitting element 40 has the pixel electrode 2 having external light reflectivity.
It is provided on the rear side of 5. When the organic EL light emitting element 40 is directed forward and emits light by itself, display is performed only in the transmissive area 12, and light is not transmitted in the reflective area 11 where the pixel electrode 25 exists.

Therefore, when the organic EL light emitting element 40 is driven, the pixel electrode 25 of the liquid crystal display element 20 functions as a black matrix. Therefore, the organic EL
The contrast of the light emitting element 40 can be maintained.

Further, in the driving method of the display device 1 of the present embodiment, one field T which is a unit time of the video signal in each display area 10 is divided into a plurality of portions, and the liquid crystal display element 20 or ON / OF of the organic EL light emitting element 40
F

Therefore, the total ON time of the liquid crystal display element 20 or the organic EL light emitting element 40 in one field T can be controlled, and moreover, the types of lighting patterns are increased and they are efficiently driven. can do.

Further, by controlling the ON time of the liquid crystal display element 20 or the organic EL light emitting element 40 in this way, it is possible to display the gradation of the video signal.

Therefore, when the liquid crystal display element 20 and the organic EL light emitting element 40, which are two display elements, are formed in the display region 10, the circuit configuration is prevented from becoming complicated,
It is possible to provide a driving method of the display device 1 which can reduce the yield and cost at the time of manufacturing and can efficiently perform gradation display.

Further, in the driving method of the display device 1 of the present embodiment, when one field which is a unit time of the video signal in each display area 10 is divided into a plurality of fields, each division width is 1: 2 ¹ : It is divided so as to have an interval of 2 ² : ...: 2 ⁿ (n is a positive integer).

That is, one field T is divided into intervals of powers of 2, and the divided period, that is, the period (4/7)
The liquid crystal display element 20 or the organic EL light emitting element 40 in one field T is turned on by the T, the period (2/7) T, and the period (1/7) T every time. It is possible to control the total ON time of the light emitting element 40, and further to increase the types of lighting patterns and to efficiently drive them.

As a result, according to this division method, 2 ⁿ gray scales can be displayed, and the number of scanning line signal selections can be reduced to increase the number of gray scales.

In the present embodiment, the driving circuit in the case where the organic EL light emitting element 40 is provided behind the pixel electrode 25 has been described, but the present invention is not limited to this, and the organic EL light emitting element 40 is a liquid crystal. The driver circuit described in this embodiment can be applied to the case where the driver circuit is provided in the same layer as the layer 26.

Further, in the above-mentioned embodiment, the reflection type liquid crystal display element 20 is used as the light modulation element, but the present invention is not necessarily limited to this. For example, a mirror or the like is used to turn on / off the light reflection amount. Alternatively, a display element capable of displaying images may be used. Further, it is possible to use an electrophoretic display, a twist ball display, a reflection display using a fine prism film, a light modulation element such as a digital mirror device.

Further, although the organic EL light emitting element 40 is used as the light emitting element, the light emitting element is not limited to this.
An element such as an L light emitting element or an LED (Light Emitting Diode) capable of controlling ON and OFF of light emission can be applied. Furthermore, a light emitting element such as a field emission display (FED) or a plasma display can be used.

Further, the insulating substrate 29 described in the above-mentioned embodiments is not necessarily hard and may be on a film.

Further, in the above embodiment, the TF for liquid crystal is used as the switching element for driving the liquid crystal display element 20.
Although the T element 22 is used, it is not necessarily limited to this.
For example, it is possible to use a MIM (Metal Insulator Metal) element for liquid crystal.

[0151]

As described above, the display device of the present invention has the first display area for displaying external light in the display area by reflecting the external light by the first electro-optical element, and the second electro-optical element. A second display area for displaying is provided side by side with a first substrate and a second substrate facing each other,
The first electro-optical element and the second electro-optical element are both provided between the first substrate and the second substrate, and the respective display areas arranged in a matrix are provided in the first electro-optical element. The data signal lines and the scanning signal lines for driving by the electro-optical element and the second electro-optical element are shared with each other.

Therefore, since the first electro-optical element and the second electro-optical element are both provided between the first substrate and the second substrate, it is possible to reduce the thickness of the display device. it can.

Further, in the present invention, each of the display areas arranged in a matrix is provided with the first electro-optical element and the second electro-optical element.
The respective data signal lines and the respective scanning signal lines for driving by the electro-optical element are commonly used. Therefore, the first electro-optical element can be driven by the data signal line and the scanning signal line for driving the first electro-optical element. This also means that each driver such as the data driver and the gate driver is shared. As a result, each display of the first electro-optical element and the second electro-optical element can be performed without increasing the number of data signal lines and scanning signal lines.

Therefore, when the two display elements are formed in the display area, the circuit structure is prevented from becoming complicated,
It is possible to provide a display device capable of reducing the yield and the cost during manufacturing.

As described above, in the display device of the present invention, the light-emitting element and the first display area, which is the non-light-emitting display element in which the light modulation element reflects external light to perform display, are provided in the display area. A second display region including a light emitting display element that directly modulates and displays is provided side by side, and a first substrate and a second substrate facing each other are provided, and both the light modulating element and the light emitting element are the above. Data signal lines and scanning signal lines provided between the first substrate and the second substrate and for driving the respective display areas arranged in a matrix by the light modulation element and the light emitting element. Are shared with each other.

Therefore, since the light modulation element and the light emitting element are both provided between the first substrate and the second substrate, the thickness of the display device can be reduced. Further, since the light emitting element emits light toward the front to directly display, the light emitting element is not used as a backlight or a front light as in the conventional case. Therefore, the utilization efficiency of light can be improved.

Further, in the present invention, the respective data signal lines and the respective scanning signal lines for driving the respective display areas arranged in a matrix by the light modulating element and the light emitting element are shared with each other. Therefore, the light emitting element can be driven by the data signal line and the scanning signal line for driving the light modulation element. As a result, each display of the light modulation element and the light emitting element can be performed without increasing the number of data signal lines and scanning signal lines.

Therefore, it is possible to prevent the circuit configuration from becoming complicated when two display elements are formed in the display area.
It is possible to provide a display device capable of reducing the yield and the cost during manufacturing.

As described above, in the display device of the present invention, the light-emitting element and the first display area, which is the non-light-emitting display element in which the light modulation element reflects external light to perform display, are provided in the display area. A second display region including a light emitting display element that directly modulates and displays is provided side by side, and a first substrate and a second substrate facing each other are provided, and both the light modulating element and the light emitting element are the above. A drive signal is provided to each data signal line and each scanning signal line which is provided between the first substrate and the second substrate and is arranged in a matrix in order to drive the display regions by the light modulation element. The light emitting element can be driven by applying the voltage.

Therefore, since the light modulation element and the light emitting element are both provided between the first substrate and the second substrate, the thickness of the display device can be reduced. Further, since the light emitting element emits light toward the front to directly display, the light emitting element is not used as a backlight or a front light as in the conventional case. Therefore, the utilization efficiency of light can be improved.

Further, according to the present invention, by applying a drive signal to each data signal line and each scanning signal line for driving the respective display areas arranged in a matrix by the light modulating element, the light emitting element is obtained. Can be driven. Therefore, the light emitting element can be driven by the data signal line and the scanning signal line for driving the light modulation element. As a result, without increasing the number of data signal lines and scanning signal lines,
Each display of the light modulation element and the light emitting element can be performed.

Therefore, when the two display elements are formed in the display area, the circuit structure is prevented from becoming complicated,
It is possible to provide a display device capable of reducing the yield and the cost during manufacturing.

Further, the display device of the present invention is the switching device for driving the light modulation device, in addition to the voltage-current conversion means for converting the voltage to the current for driving the light emitting device in the display device described above. The drain electrode of the light modulation element transistor is connected to the voltage-current conversion means.

Therefore, by connecting the drain electrode to the voltage / current converting means and converting the voltage into the current by the voltage / current converting means, the light emitting element can be surely caused to emit light.

According to the display device of the present invention, in the display device described above, the voltage-current converting means comprises a light emitting element transistor, and the threshold voltage of the light emitting element transistor for driving the light emitting element is a light modulation element. Is larger than the drive voltage of.

Therefore, when the light modulation element is driven, a drive voltage lower than the threshold voltage of the light emitting element transistor is applied to the data line signal, while when driving the light emitting element, it is higher than the threshold voltage of the light emitting element transistor. By applying a high driving voltage to the data line signal, the light emitting element can also emit light. That is, in the present invention, the reflective display and the light emitting display can be easily selected by controlling the threshold voltage of the light emitting element transistor of the light emitting element. As a result, it is possible to reliably prevent the circuit configuration from becoming complicated and to drive the light modulation element and the light emitting element with one scanning signal line and one data signal line.

The display device of the present invention is the display device described above, wherein the voltage-current converting means is composed of a light emitting element transistor, and drives the ON operation region of the light emitting element transistor and the light modulation element. The ON operation region of the light modulation element transistor is divided by the threshold voltage.

Therefore, when driving the light modulation element, a driving voltage lower than the threshold voltage of the light emitting element transistor is applied to the data line signal, while when driving the light emitting element, it is higher than the threshold voltage of the light emitting element transistor. By applying a high driving voltage to the data line signal, the light emitting element can also emit light.

As a result, it is possible to reliably prevent the circuit configuration from becoming complicated and to drive the light modulation element and the light emitting element with one scanning signal line and one data signal line.

The display device of the present invention is characterized in that, in the display device described above, the characteristic of the light modulation element is normally white.

Therefore, when driving the light emitting element,
As described above, the light modulation element is in a driving state, and its display is black.

As a result, the second display area of the light emitting element
Since black is displayed around the display area, it is possible to prevent a decrease in contrast caused by driving the light emitting element to emit light.

The display device of the present invention is the display device as described above, wherein the light modulation element is a liquid crystal display element.

Therefore, it is possible to easily provide a display device which can prevent the circuit configuration from becoming complicated when two display elements are formed in the display region, and can reduce the yield and the cost during manufacturing. There is an effect that can be.

Further, the display device of the present invention is the display device described above, wherein a pixel electrode having external light reflectivity is provided, and the counter electrode facing the pixel electrode is the entire surface of the display region on the second substrate side. And is driven by the potential of the counter electrode when displaying by the light modulation element, and is driven by the potential of the reference electrode when displaying by the light emitting element.

Therefore, when the display is performed by the light modulation element, it is driven with respect to the potential of the counter electrode, while when the display is performed with the light emitting element, it is driven with respect to the potential of the reference electrode.

Therefore, when a liquid crystal display element is used as the light modulation element, the light modulation element and the light emitting element can be driven reliably and appropriately.

The display device of the present invention is the display device described above, wherein the light emitting element is provided on the rear side of the pixel electrode having external light reflectivity, and the light emitting element is on the front side of the display surface. When it emits light toward itself, display is performed only in the second display area, and the pixel electrode is present in the first display area.
Light is non-transmissive in the display area.

Therefore, when driving the light emitting element,
The pixel electrode of the light modulation element functions as a black matrix. As a result, it is possible to maintain the contrast of the light emitting element.

Further, according to the driving method of the display device of the present invention, one field which is a unit time of the video signal in each display area is divided into a plurality of times by using the display device described above, and the light is output in each divided period. This is a method of turning ON / OFF the modulation element or the light emitting element.

Therefore, it is possible to control the total ON time of the light modulation element or the light emitting element in one field, and further, to increase the types of lighting patterns and efficiently drive them.

Also, by controlling the ON time of the light modulation element or the light emitting element temporally in this way, it becomes possible to display the gradation of the video signal.

Therefore, when the two display elements are formed in the display area, the circuit structure is prevented from becoming complicated,
It is possible to provide a method for driving a display device, which can reduce the manufacturing yield and cost and can efficiently perform gradation display.

The display device driving method of the present invention is the same as the above-described display device driving method, when one field, which is a unit time of a video signal in each display area, is divided into a plurality of divisions. The width is 1: 2 ¹ : 2 ² : ...: 2
^This is a method of dividing into ⁿ (n is a positive integer) intervals.

Therefore, according to this division method, 2 ⁿ gray scales can be displayed, and the number of scanning line signal selections can be reduced to increase the number of gray scales.

[Brief description of drawings]

FIG. 1 shows an embodiment of a display device according to the present invention, and is a circuit configuration diagram for one pixel.

FIG. 2 is a plan view showing one pixel in the display device.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is an overall configuration diagram showing the display device.

FIG. 5 is another circuit configuration diagram of one pixel in the display device.

FIG. 6 is a signal waveform diagram when the display device is driven.

FIG. 7 is a characteristic diagram showing a display state by a data line signal in the above display device, in which a horizontal axis indicates a data line signal and a vertical axis indicates a reflection amount during reflective display and a light emission amount during light emitting display. .

FIG. 8 is an explanatory diagram showing another configuration of the voltage-current conversion means.

9A to 9C show another embodiment of the display device of the present invention, and are signal waveform diagrams when the display device is driven.

FIG. 10 is a cross-sectional view showing a conventional liquid crystal display device.

[Explanation of symbols]

1 Display Device 2a Source Bus Line (Data Signal Line) 2b Current Supply Line 3 Gate Bus Line (Scanning Signal Line) 4 External Light 5 Display Light 6 Source Driver 7 Gate Driver 10 Display Pixel (Display Area) 11 Reflection Area (First Display area) 12 Transmission area (second display area) 20 Liquid crystal display element (light modulation element) 21 Insulating substrate (first substrate) 22 Liquid crystal TFT element (light modulation element transistor) 22a Drain electrode (light modulation element) Drain electrode of transistor) 24 Transparent insulating layer 25 Pixel electrode 25a Opening 26 Liquid crystal layer 27 Counter electrode 29 Insulating substrate (second substrate) 31 Phase difference plate 32 Polarizing plate 40 Organic EL light emitting element (light emitting element) 42 TFT for EL Element (voltage / current conversion means, transistor for light emitting element) 45 Cathode (reference electrode) Vdd Supply voltage Vth (LC) Threshold voltage Vth (OLED) EL threshold voltage crystals (threshold voltage of the light-emitting element) Vs data line signals

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02F 1/15 506 G02F 1/15 506 5C006 G09F 9/35 G09F 9/35 5C080 G09G 3/20 624 G09G 3 / 20 624B 5C094 641 641E 5F110 680 680H 3/30 3/30 J 3/36 3/36 H01L 29/786 H05B 33/14 A H05B 33/14 H01L 29/78 614 612C (72) Inventor Narutaki Yozo Osaka 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture F-terms within SHARP Co., Ltd. (reference) 2H091 FA14X FA14Y FA15X FA15Y FD04 GA02 LA11 LA12 LA13 LA16 LA30 MA03 MA10 2H092 GA12 GA17 GA21 GA24 JB22 JB31 NA27 PA00 PA06 QA18 RA10 2H093 NA21 NA02 NC11 ND01 ND02 ND49 ND53 ND54 ND60 NE10 2K001 AA01 BA04 EA05 3K007 AB 17 AB18 DB03 GA04 5C006 AA14 AF69 AF75 BB16 BB28 BC06 BC08 BF34 FA03 FA05 FA42 FA43 FA47 FA51 5C080 AA06 AA10 BB05 CC08 DD01 DD23 DD26 DD28 EE29 FF11 FF12 JJ03 BA04 BA74 BA74 BA74 BA04 A04 BA04 A04 A45 A04 A45 A04 A04 A45 A04 A45 A47 A04 A45 A47 A45 DB04 EA04 FB14 HA08 JA01 5F110 AA09 AA30 BB01 DD02 HL03 HL04 HL23 NN02 NN27 NN72 NN73 NN78

Claims (12)

[Claims] 1. A first display area for displaying by external light reflected by a first electro-optical element and a second display area for displaying by a second electro-optical element are provided side by side in the display area. On the other hand, a first substrate and a second substrate facing each other are provided, and the first electro-optical element and the second electro-optical element are both provided between the first substrate and the second substrate. In addition, each data signal line and each scanning signal line for driving the respective display areas arranged in a matrix by the first electro-optical element and the second electro-optical element are shared with each other. A display device characterized by being. 2. A first display area comprising a non-light emitting display element in which a light modulation element reflects external light to perform display in the display area, and a light emitting display element in which the light emitting element directly modulates to perform display. Two display areas are provided side by side, and a first substrate and a second substrate facing each other are provided, and the light modulation element and the light emitting element are both the first substrate and the second substrate.
The data signal lines and the scanning signal lines for driving the display areas arranged in a matrix with the substrate by the light modulation element and the light emitting element are shared with each other. A display device characterized by the above. 3. A first display area comprising a non-light emitting display element in which a light modulation element reflects external light to perform display in the display area, and a light emitting display element in which the light emitting element directly modulates to perform display. Two display areas are provided side by side, and a first substrate and a second substrate facing each other are provided, and the light modulation element and the light emitting element are both the first substrate and the second substrate.
By applying a drive signal to each data signal line and each scanning signal line for driving the respective display areas arranged in a matrix with the light modulation element while being provided between the substrate, A display device in which a light emitting element can be driven. 4. A voltage-current conversion means for converting a voltage into a current for driving a light-emitting element is provided, and a drain electrode of a light modulation element transistor, which is a switching element for driving the light modulation element, has the voltage-current conversion means. The display device according to claim 2, wherein the display device is connected to. 5. The voltage-current converting means comprises a light emitting element transistor, and a threshold voltage of the light emitting element transistor for driving the light emitting element is higher than a drive voltage of the light modulation element. Item 4. The display device according to item 4. 6. The voltage-current conversion means comprises a light emitting element transistor, and the ON operation area of the light emitting element transistor and the ON operation area of the light modulation element transistor for driving the light modulation element have a threshold voltage. The display device according to claim 4, wherein the display device is sorted by. 7. The display device according to claim 4, 5 or 6, wherein the characteristic of the light modulation element is normally white. 8. The display device according to claim 2, wherein the light modulation element is a liquid crystal display element. 9. A pixel electrode having external light reflectivity is provided,
Further, the counter electrode facing the pixel electrode is provided on the entire surface of the display region on the second substrate side, and when the display is performed by the light modulation element, the counter electrode is driven to the potential of the counter electrode while the light emitting element performs the display. 9. The display device according to claim 8, wherein the display device is sometimes driven with respect to the potential of the reference electrode. 10. The light emitting element is provided on the rear side of the pixel electrode having external light reflectivity, and when the light emitting element itself emits light toward the front display surface side, only the second display area is displayed. And light is not transmitted in the first display region in which the pixel electrode is present.
10. The display device according to any one of items 9 to 9. 11. The display device according to claim 1, wherein one field, which is a unit time of a video signal in each display area, is divided into a plurality of areas, and an optical signal is generated for each divided period. A method for driving a display device, comprising turning on / off a modulation element or a light emitting element. 12. When dividing one field, which is a unit time of a video signal in each display area, into a plurality of fields, each division width is 1: 2 ¹ : 2 ² : ...: 2 ⁿ (n is a positive integer) 12. The driving method for a display device according to claim 11, wherein the display device is divided so as to have an interval of).