JP2010015083A - Display and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display and a liquid crystal display with a high numerical aperture, enabling high definition display with a high visibility in both bright place and dark place with a low power consumption. <P>SOLUTION: A thin film transistor substrate 20 includes: a transparent electrode 3 for controlling the luminance of transmitted light of pixel 1; a reflection electrode 2 placed side by side with the transparent electrode 3 for controlling the luminance of reflected light of the pixel 1; a signal line 4 for transmitting video information and the like to the transparent electrode 3 and the reflection electrode 2; scanning lines 5A, 5B disposed crossing the signal line 4 for controlling the drive of thin film transistors 10A, 10B; and auxiliary capacity wiring 9 for forming an auxiliary capacity for stabilizing the potential of the pixel 1. The auxiliary capacity wiring 9 is provided below the reflection electrode 2. The thin film transistors 10A, 10B are provided below the signal line 4, or below the reflection electrode 2 or below the scanning lines 5A, 5B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display device and a liquid crystal display device having functions of both a reflective display and a transmissive display.

  Since liquid crystal display devices are characterized by thinness, light weight, and low power consumption, they are used for display devices for mobile phones, personal computer displays, and televisions from small to large sizes. Yes.

  In particular, portable phones, PDAs (Personal Data Assistance), and notebook computers are battery-powered, and are used in different places with external light. It is thought that many displays with this will be needed in the future.

For example, in Patent Document 1, a transflective reflector is prepared between a panel portion including a pair of substrates facing each other with a liquid crystal layer interposed therebetween and a backlight for illuminating. A two-way display type liquid crystal display device that operates as a transmissive type (in which light from the backlight enters from the back side of the panel and exits to the front side) in the dark. It is disclosed. Since the transmission path of light to the liquid crystal layer is different between the case of operating as a reflective type and the case of operating as a transmissive type, the display quality (transmittance) is different. In order to make this match, by applying different signal voltages between the reflective type operation and the transmissive type operation and matching the transmittance, low power consumption and visibility in both bright and dark places High-performance display is realized (prior art (1))
On the other hand, in recent years, a reflective electrode part and a transparent electrode part are prepared in one pixel region, and these are connected to each other, and in the dark place, only the transmitted light from the backlight is used in the transparent electrode part. A transflective liquid crystal display device that can secure high visibility even when the brightness of the backlight is insufficient in a bright place by adding the reflected light from the reflective electrode portion is widely used. Further, in order to make the transmission path length of light to the liquid crystal layer equal between the reflective electrode portion and the transparent electrode portion, the thickness of the liquid crystal layer differs between the reflective portion and the transmissive portion (see Patent Document 3). Patent Documents 4 and 5 describe a liquid crystal display device in which a thin film transistor is formed below a signal line.

  FIG. 13 shows a configuration of a general transflective liquid crystal display device. FIG. 13 is a plan view showing a configuration of a conventional transflective liquid crystal display device. Note that in FIG. 13, a part of the substrate on which the thin film transistor is formed is extracted from the pair of transparent substrates facing each other with the liquid crystal layer interposed therebetween. FIG. 13 shows one pixel having a pair of transmission part and reflection part and one adjacent pixel arranged adjacent to this pixel.

  As shown in FIG. 13, the pixel 100 representing one pixel includes a reflective electrode unit 105 that reflects incident light, a transparent electrode unit 104 connected to the reflective electrode unit 105, and a video signal to the pixel 100. A signal wiring 101 for applying, a scanning line 102 arranged to cross the signal wiring 101 for controlling on / off (driving) of the switching element, and a video signal transmitted to the signal wiring 101 are transparent A thin film silicon 116A constituting a thin film transistor 103B to be described later supplied to the electrode 104 or the reflective electrode 105, a thin film silicon 116B for auxiliary capacitance, and an auxiliary capacitance wiring 119 for forming an auxiliary capacitance together with the thin film silicon 116B are formed. Yes. The auxiliary capacitor is for stabilizing the drive potential of the pixel 100.

  The scanning line 102 is formed across a plurality of pixels 100, and the signal wiring 101 is formed beside the transmission part 110 and the reflection part 111 so as to intersect the scanning line 102. The thin film transistor (TFT) 103B is formed in a region where the scanning line 102 and the signal wiring 101 intersect.

  The thin film silicon 116 </ b> A is connected to the signal wiring 101 by a thin film transistor contact 121. The thin film silicon 116 </ b> A passes below the scanning line 102 and is connected to the reflective electrode 105 by the transmissive reflective electrode contact 114. The thin film silicon 116 </ b> B is formed below the auxiliary capacitance wiring 119, and is connected to the reflective electrode 105 by the transmission / reflection electrode contact 114. FIG. 13 shows a case where the transparent electrode portion 104 and the reflective electrode portion 105 overlap the signal wiring 101.

  14 is a cross-sectional view taken along line D-D ′ shown in FIG. 13. As shown in FIG. 14, the pixel 100 includes a thin film transistor substrate 120 on which a thin film transistor is formed, and a counter substrate 130 disposed to face the thin film transistor substrate 120.

  In the thin film transistor substrate 120, thin film silicon 116 </ b> B is formed on the transparent substrate 108 with the passivation film 106 interposed therebetween. An interlayer insulating film 107 is formed on the passivation film 106 so as to cover the thin film silicon 116B. A scanning line 102 and an auxiliary capacitance wiring 119 are formed above the thin film silicon 116B with an interlayer insulating film 107 interposed therebetween. Further, the reflective electrode portion 105 and the transparent electrode portion 104 are in contact with each other on the upper layer of the interlayer insulating film 107 and formed in parallel. A region where the reflective electrode portion 105 is formed is the reflective portion 111. A region where the reflective electrode portion 105 is not formed is the transmission portion 110.

  The scanning line 102 and the auxiliary capacitance line 119 are formed below the reflective electrode portion 105, and are arranged side by side (horizontal with respect to the film surface) with a gap in the middle layer of the interlayer insulating film 107. Yes. A thin film silicon 116 </ b> B is formed in contact with the passivation film 106 below the auxiliary capacitance wiring 119.

  The counter substrate 130 is a lower layer of the transparent substrate 108 (on the side where the thin film transistor substrate 120 is disposed), and a resin layer 109 is formed in a region facing the reflective electrode portion 105. A transparent electrode portion 112 is formed below the transparent substrate 108 so as to cover the resin layer 109. A color filter (not shown) is formed.

  A liquid crystal layer 140 is formed between the thin film transistor substrate 120 and the counter substrate 130. A backlight (not shown) is formed below the transparent substrate 108 of the thin film transistor substrate 120.

  Thereby, in the reflection part 111, the light which injects from the back surface side of the opposing board | substrate 130, ie, the upper direction of the transparent substrate 108 of the opposing board | substrate 130 permeate | transmits the resin layer 109, is reflected by the reflective electrode part 105, and is again a resin layer. 109 is transmitted through the transparent substrate 108. On the other hand, in the transmissive part 110, when light is emitted from a backlight (not shown), the light passes through the transparent electrode part 104 juxtaposed with the reflective electrode part 105 and is emitted above the transparent substrate 108 of the counter substrate 130.

  Thus, in the reflection part 111, light passes through the liquid crystal layer 140 twice. On the other hand, in the transmission part 110, the light passes through the liquid crystal layer 140 only once. Therefore, the resin layer 109 is formed on the reflective portion 111 so that the thickness of the liquid crystal layer 140 is different between the transmissive portion 110 and the reflective portion 111. Thereby, the path length of the light which passes the liquid crystal layer 140 by the reflection part 111 and the transmission part 110 is made the same.

  By so doing, the luminance characteristics of the transmission unit 110 and the reflection unit 111 can be made to coincide as shown in FIG. 15 with the luminance characteristics of the transmission unit 110 and the reflection unit 111. The horizontal axis of the graph shown in FIG. 15 represents the voltage applied to the liquid crystal layer 140, and the vertical axis represents the luminance normalized by the maximum luminance with respect to the voltage applied to the liquid crystal layer 140 (prior art (2)). .

  Further, Patent Document 2 discloses a configuration in which a reflective electrode portion and a transmissive electrode portion are formed in one pixel, and a thin film transistor is formed in each of them. This will be described with reference to FIG.

  FIG. 16 is a plan view showing a configuration of a conventional transflective liquid crystal display device, in which thin film transistors are formed in each of the reflective electrode portion and the transmissive electrode portion. In FIG. 16, one pixel having a pair of transmission part and reflection part and one adjacent pixel arranged adjacent to this pixel are shown.

  As shown in FIG. 16, the pixel 200 of the transflective liquid crystal display device represents one pixel similarly to the pixel 100 shown in FIG. 13, and a reflective electrode portion 205 and a transparent electrode portion 204 are juxtaposed on the pixel 200. Has been formed. The pixel 200 is different from the pixel 100 in that a thin film transistor is provided in each of the transparent electrode 204 and the reflective electrode 205, and each of the transparent electrode 204 and the reflective electrode 205 can be independently driven and controlled.

  As shown in FIG. 16, the pixel 200 includes a signal wiring 201 for applying a video signal to the pixel 100 and a thin film transistor 203 </ b> A for turning on / off the supply of the video signal to the pixel 200 according to the selection of the pixel 200. 203B, scanning line wiring 202 for turning on the thin film transistors 203A and 203B when the pixel 200 is selected, a transparent electrode portion 204 connected to the thin film transistor 203A, and a reflective electrode portion 205 connected to the thin film transistor 203B. The transparent electrode portion 204 and the reflective electrode portion 205 are electrically independent.

Thereby, in the pixel 200, each of the transparent electrode part 204 and the reflective electrode part 205 can be driven independently. For this reason, when the pixel 200 is used as a reflective type, a voltage is applied only to the reflective electrode unit 205, and when the pixel 200 is used as a transmissive type, only a voltage is applied to the transparent electrode unit 204, Power consumption is achieved (Prior Art (3)).
JP 2000-193936 A JP-A-11-305248 Special table 2005-524115 published JP-A-2-176726 Japanese Patent Laid-Open No. 9-146117

  However, in the configuration of the prior art (1), the loss of light at the transflective plate installed between the panel unit and the backlight that performs illumination is large. In addition, when the reflective type and the transmissive type are operated, the number of transmissions of the color filter that performs color display is different. Therefore, even if different signal voltages are applied and the transmittance is the same, the display quality is different in bright and dark places There's a problem.

  13 and 14 solves the problem of light loss in the transflective plate of the prior art (1). However, as described above, the reflective portion 111 and the transmissive portion 110 are solved. In order to make the optical path lengths equal to each other, the distance between the thin film transistor substrate 120 and the counter substrate 130 in the reflection portion 111 is set to ½ of the distance between the thin film transistor substrate 120 and the counter substrate 130 in the transmission portion 110. That is, the thickness of the liquid crystal layer 140 in the reflective portion 111 is ½ of the thickness of the liquid crystal layer 140 in the transmissive portion 110.

Here, it is generally known that the response time τ of the liquid crystal is proportional to the square of the viscosity η of the liquid crystal and the thickness d of the liquid crystal layer (τ˜η × d ² ).

  For this reason, in the configuration described in the prior art (2), the response time of the liquid crystal is different between the reflection unit 111 and the transmission unit 110, and it is difficult to adjust overshoot driving or the like that drives the liquid crystal at high speed.

  In the prior art (3) shown in FIG. 16, since the signal voltage is applied independently between the reflective electrode portion 205 and the transparent electrode portion 204, different thicknesses of the liquid crystal layer 140 are prepared as shown in FIG. There is no need. However, since the thin film transistor 203A or the thin film transistor 203B is prepared for each of the reflective electrode portion 205 and the transparent electrode portion 204 of the pixel 200, both the reflective electrode portion 205 and the transparent electrode portion 204 reduce the aperture ratio. There's a problem. In addition, no consideration is given to the auxiliary capacity.

  The present invention solves the above-described problems, and an object of the present invention is to provide a display device and a liquid crystal that have a high aperture ratio, high visibility in a bright place and a dark place, high quality display, and low power consumption. It is to provide a display device.

  In order to solve the above problems, the display device of the present invention is a liquid crystal display device including a first substrate provided with a switching element that controls driving of a pixel serving as a display unit. A transparent electrode that controls the luminance of light transmitted through the pixel, a reflective electrode that is juxtaposed with the transparent electrode and controls reflection of light incident on the pixel, and transmits a data signal to the transparent electrode and the reflective electrode A signal line; a scan line that is disposed orthogonal to the signal line and controls driving of the switching element; and an auxiliary capacitance wiring that forms an auxiliary capacitance for stabilizing the potential of the pixel. Capacitance wiring is provided below the reflective electrode, and the switching element is different from the transparent electrode switching element that controls the driving of the transparent electrode. A reflective electrode switching element that controls driving of the reflective electrode, and the transparent electrode switching element and the reflective electrode switching element are located below the signal line or the reflective electrode. It is provided below or below the scanning line.

  The transparent electrode and the reflective electrode are provided with a transparent electrode switching element and a reflective electrode switching element, which are different switching elements. Accordingly, by controlling the driving of the scanning line, different voltages can be applied independently to the reflective electrode and the transparent electrode. For this reason, in the case where, for example, video information or text information (hereinafter referred to as video information) is displayed on the pixel by reflecting light in a bright place (hereinafter referred to as reflective display), the transparent electrode Does not apply a voltage for driving the pixel, and can apply the voltage only to the reflective electrode. Conversely, when video information or the like is displayed on the pixel by transmitting light from a lighting device in a dark place (hereinafter referred to as transmissive display), the pixel is driven by the reflective electrode. Therefore, it is possible to apply a voltage only to the transmissive electrode without applying a voltage. Accordingly, it is not necessary to apply an extra voltage, and thus the display device can be configured with low power consumption.

  According to the above configuration, the auxiliary capacitance wiring is provided below the reflective electrode, and the transparent electrode switching element and the reflective electrode switching element are provided below the signal line or the reflective electrode. It is provided below the electrodes or below the scanning lines.

  For this reason, the light emitted from the illuminating device is not shielded by the auxiliary capacitance wiring, the transparent electrode switching element, and the reflective electrode switching element.

  Furthermore, the area of the transparent electrode can be increased. For this reason, the auxiliary capacitance wiring is not formed below the reflective electrode, and the transparent electrode switching element and the reflective electrode switching element are any of the signal line, the reflective electrode, and the scanning line. The aperture ratio can be improved as compared with the case where it is not formed below.

  Thus, with the above structure, a display device with a high aperture ratio, high visibility in a bright place or a dark place, high-quality display, and low power consumption can be realized.

  In the display device according to the aspect of the invention, the scanning line may further include a transparent electrode scanning line that controls driving of the transparent electrode switching element, and a reflective electrode scanning line that controls driving of the reflective electrode switching element. The transparent electrode scanning line and the reflective electrode scanning line include a first gap between the transparent electrode and the reflective electrode, a reflective electrode, and a pixel different from the pixel adjacent to the reflective electrode; It is preferable that the first gap, the reflective electrode, and the second gap are formed in a region below the second gap between the reflective electrode and the second gap.

  Further, it is more preferable that both the transparent electrode scanning line and the reflective electrode scanning line are formed below the reflective electrode.

  According to the above configuration, the auxiliary capacitance electrode, the transparent electrode scanning line, and the reflective electrode scanning line are not formed below the transparent electrode. For this reason, light emitted from the illumination device is not shielded by the auxiliary capacitance electrode, the transparent electrode scanning line, and the reflective electrode scanning line, so that the aperture ratio of the pixel can be further improved. it can.

  In the display device according to the aspect of the invention, it is preferable that the transparent electrode scanning line, the reflective electrode scanning line, and the auxiliary capacitance wiring are formed in the same layer.

  Thus, the transparent electrode scanning line, the reflective electrode scanning line, and the auxiliary capacitance wiring can be formed in the same process. For this reason, it is not necessary to provide a separate process for forming each of the wirings.

  In the display device according to the aspect of the invention, it is preferable that the transparent electrode scanning line and the reflective electrode scanning line are formed with the auxiliary capacitance wiring interposed therebetween.

  With the above configuration, the auxiliary capacitance wiring for the transparent electrode and the auxiliary capacitance wiring for the reflective electrode can be configured by a common wiring. Therefore, the area for providing the auxiliary capacity can be reduced.

  In the display device of the present invention, further below the auxiliary capacitance line, there is a transparent electrode thin film silicon constituting the auxiliary capacitance for the transparent electrode, and a reflective electrode thin film silicon constituting the auxiliary capacitance for the reflective electrode. It is preferable that the connection between the transparent electrode and the thin film silicon for transparent electrode and the connection between the reflective electrode and the thin film silicon for reflective electrode are made through an intermediary layer.

  Thereby, the connection between the transparent electrode and the thin-film silicon for transparent electrode and the connection (contact) between the reflective electrode and the thin-film silicon for reflective electrode are each compared with a case where a single wiring is used. Can be prevented.

  In the display device of the present invention, a first contact for connecting the reflective electrode and the mediating layer, and a second contact for connecting the mediating layer and the thin film silicon for the reflective electrode are further provided. The second contact is preferably formed below the transparent electrode of a different pixel adjacent to the pixel.

  Thereby, the wiring for connecting the transparent electrode and the thin film silicon for transparent electrode, and the wiring for connecting the reflective electrode and thin film silicon for the reflective electrode are connected to the scanning line for the transparent electrode, the scanning line for the reflective electrode, and the The auxiliary capacitance wiring can be provided.

  According to the said structure, the said reflecting electrode and the said thin film silicon | silicone for reflecting electrodes are connected by the said 2 contact via the said mediation layer.

  More preferably, it is preferable that the reflective electrode scanning line is formed between the first contact and the second contact in an area in plan view.

  According to the above configuration, the reflective electrode and the reflective electrode thin film silicon are connected across the reflective electrode scanning line and the auxiliary capacitance wiring. Therefore, it is not necessary to form a wiring for connecting the reflective electrode and the reflective electrode thin film silicon between the reflective electrode scanning line and the auxiliary capacitance wiring.

  As a result, it is possible to reduce the gap between the reflective electrode scanning line and the auxiliary capacitance wiring, and realize a high aperture ratio while forming the reflective electrode scanning line under the reflective electrode. It becomes possible to do.

  Therefore, the first gap between the transparent electrode and the reflective electrode, the reflective electrode, and the second gap between the reflective electrode and a different pixel adjacent to the reflective electrode, and the first gap, The transparent electrode scanning line, the reflective electrode scanning line, and the auxiliary capacitance wiring are provided in a region in plan view of the reflective electrode and the second gap, and both switching elements are connected to the signal line, the reflective electrode, and the scanning. The transparent electrode and the reflective electrode can be driven independently while adopting a wiring layout that realizes a high aperture ratio that is provided below any of the lines.

  In the display device of the present invention, a third contact for connecting the transparent electrode and the mediating layer, and a fourth contact for connecting the mediating layer and the thin film silicon for transparent electrodes are provided. The fourth contact is preferably formed below the reflective electrode.

  According to the said structure, it is not necessary to provide the said thin film silicon | silicone for transparent electrodes below the said scanning line for transparent electrodes. For this reason, it becomes possible to form the mediation layer in a layer between the transparent electrode scanning line and the transparent electrode, and to connect the transparent electrode and the thin film silicon for transparent electrode. Thereby, compared with the case where the transparent electrode thin film silicon is formed below the transparent electrode scan line and the signal line and the transparent electrode are connected, the load of the transparent electrode scan line, It is possible to reduce the load of wiring for connecting the transparent electrode and the thin film silicon for transparent electrode.

  A wiring layout that realizes a high aperture ratio is provided in which the auxiliary capacitance wiring is provided below the reflective electrode, and both switching elements are provided below any one of the signal line, the reflective electrode, and the scanning line. However, the transparent electrode and the reflective electrode can be driven independently.

  In the display device, it is preferable that a γ curve is different between a region corresponding to the transparent electrode and a region corresponding to the reflective electrode in the pixel.

  Thereby, by adjusting the voltage applied to the transparent electrode and the reflective electrode, the contrast can be adjusted according to the surrounding environment in which the display device is used.

  Therefore, it is possible to configure a display device including pixels that can display high-quality video information with high visibility regardless of the intensity of external light with high luminance.

  In the display device, regarding the first data signal transmitted to the transparent electrode among the data signals, the voltage change of the first data signal with respect to the input signal input to the display device; and Among the data signals, regarding the second data signal transmitted to the reflective electrode, the voltage curve of the second data signal with respect to the input signal input to the display device is different, so that the γ curve is different. Is preferred.

  Thus, by modulating the input signal input to the display device, the voltage change of the first data signal with respect to the input signal, and the voltage change of the second data signal with respect to the input signal, The voltage applied to the transmissive part and the reflective part is changed to an appropriate one. As a result, by changing the γ curve between the first data signal and the second data signal, an optimal image is displayed in both the dark and bright areas, so that it depends on the surrounding environment in which the display device is used. Thus, the contrast can be adjusted.

  The liquid crystal display device of the present invention further includes the display device, a liquid crystal layer, and a second substrate disposed opposite to the first substrate with the liquid crystal layer interposed therebetween, the transparent electrode and It is preferable that the thickness of the liquid crystal layer between the second substrates is equal to the thickness of the liquid crystal layer between the reflective electrode and the second substrate.

  Here, in the case of a reflective display in which external light is reflected by the reflective electrode and the video information or the like is displayed on the pixel, the external light is reflected by the reflective electrode and emitted when entering the pixel. It passes through the liquid crystal layer twice. On the other hand, in the case of transmissive display in which the image information and the like are displayed on the pixels by transmitting the light from the illumination device through the transparent electrode, the light from the illumination device passes through the liquid crystal layer once. become.

  Thus, the light transmission path is different between the reflective display and the transmissive display. Therefore, the thickness of the liquid crystal layer between the transparent electrode and the second substrate is equal to the thickness of the liquid crystal layer between the reflective electrode and the second substrate, and the transparent electrode and the second substrate In the case where the reflective electrode is not individually driven and controlled, the reflected light in the reflective display undergoes a double retardation change compared to the transmitted light in the transmissive display. That is, the reflected light when performing the reflective display is more likely to change in luminance with respect to the applied voltage as compared with the transmitted light when performing the transmissive display, and the luminance characteristics are different between the reflective display and the transmissive display. .

  Therefore, in order to match the luminance characteristics between the reflective display and the transmissive display, the thickness of the liquid crystal layer in the region where the reflective electrode is formed is half that of the liquid crystal layer in the region where the transmissive electrode is formed. It is necessary to.

  On the other hand, in the present invention, since different switching elements are connected to each of the transmissive electrode and the reflective electrode, it is possible to apply different voltages to the reflective electrode and the transmissive electrode independently of each other. Become.

  For this reason, it is not necessary to make the thickness of the liquid crystal layer of the reflective electrode different from the thickness of the liquid crystal layer of the transparent electrode portion. Further, as described above, the liquid crystal layer thickness of the reflective electrode portion and the liquid crystal layer thickness of the transmissive electrode portion are equal to each other, so that the response speed of the liquid crystal of the reflective display portion and the liquid crystal layer of the transmissive display portion can be reduced. The response speed can be made equal. For this reason, the display speed of the video information or the like can be made constant between the reflective display and the transmissive display. In addition, since it is not necessary to reduce the thickness of the liquid crystal layer in the reflective electrode portion by forming a resin film, for example, the manufacturing of the first substrate or the second substrate can be simplified.

  In the liquid crystal display device, a color filter is further formed in a region corresponding to the pixel on the second substrate, a region facing the transparent electrode of the color filter, and a region facing the reflective electrode It is preferable that the color tone is different.

  With the above configuration, the γ characteristic is different between the case where the transmissive display is performed and the case where the reflective display is performed. Thereby, the contrast of a pixel can be adjusted according to the use environment of a liquid crystal display device by adjusting the voltage applied to the said transparent electrode and the said reflective electrode. Thereby, a highly visible liquid crystal display device can be provided regardless of the usage environment of the liquid crystal display device.

  In the liquid crystal display device, when a voltage for displaying information on the pixel is applied to the transparent electrode or the reflective electrode, the voltage is higher or lower than the voltage for displaying information on the pixel. After applying the voltage, it is preferable to apply a voltage for displaying information on the pixel.

  According to the configuration, the voltage for displaying information on the transparent electrode or the reflective electrode before the voltage for displaying information on the pixel is applied to the transparent electrode or the reflective electrode. Overshoot driving is performed to improve the response speed of the liquid crystal by applying a larger or smaller voltage. Thereby, the display quality of a moving image with a high display speed can be improved.

  Here, in the liquid crystal display device, the thickness of the liquid crystal layer on the transparent electrode and the thickness of the liquid crystal layer on the reflective electrode are equal. In general, the response speed of the liquid crystal is proportional to the square of the viscosity of the liquid crystal and the thickness of the liquid crystal layer. Therefore, the response speed is equal between the liquid crystal on the transparent electrode and the liquid crystal on the reflective electrode.

  For this reason, the overshoot drive waveform applied to the transparent electrode can be matched with the overshoot drive waveform applied to the reflective electrode.

  For this reason, it becomes easy to adjust the voltage applied to the transparent electrode and the voltage applied to the reflective electrode. Therefore, it is possible to easily configure a liquid crystal display device that has a high response speed in each of the transmissive display and the reflective display.

  As described above, the display device according to the present invention includes a first substrate provided with a switching element that controls driving of a pixel serving as a unit of display, and the first substrate includes the pixel. A transparent electrode for controlling the brightness of transmitted light, a reflective electrode for controlling the reflection of light incident on the pixel, and a signal line for transmitting a data signal to the transparent electrode and the reflective electrode; A scanning line that is arranged to cross the signal line and controls the driving of the switching element, and an auxiliary capacitance line that forms an auxiliary capacitance for stabilizing the potential of the pixel. The transparent electrode switching element that is provided below the reflective electrode and controls the driving of the transparent electrode is different from the transparent electrode switching element. A reflective electrode switching element that controls driving of the reflective electrode, and the transparent electrode switching element and the reflective electrode switching element are provided below the signal line or of the reflective electrode. The configuration is provided below or below the scanning line.

  Therefore, it is possible to provide a display device with a high aperture ratio, high visibility in a bright place and a dark place, high-quality display, and low power consumption.

(1. Description of pixel configuration)
One embodiment of the present invention is described below with reference to FIGS. In addition, this invention is not limited to the following embodiment.

  The structure of the pixel of the liquid crystal display device according to this embodiment will be described with reference to FIGS.

  FIG. 1 is a plan view of a pixel 1 according to the liquid crystal display device according to the present embodiment. In particular, FIG. 1 illustrates the surface of a substrate on which a thin film transistor is formed, of a pair of transparent substrates facing each other with a liquid crystal layer interposed therebetween. In FIG. 1, one pixel having a pair of transmission part and reflection part and one adjacent pixel arranged adjacent to this pixel are shown.

  FIG. 2 is a cross-sectional view taken along line A-A ′ shown in FIG. 1.

  A pixel 1 represents one pixel which is a minimum unit constituting a video or a character displayed on the liquid crystal display device.

  The pixel 1 is provided with a reflection part 12 for reflecting light and a transmission part 13 for transmitting light. A reflective electrode 2 that controls reflection of light incident on the reflective portion 12 is formed on the reflective portion 12. Further, the transparent electrode 3 that controls the luminance of light transmitted through the transmissive portion 13 is formed in the transmissive portion 13. The reflective electrode 2 and the transparent electrode 3 are arranged with a space therebetween.

  Further, the pixel 1 intersects the signal line 4 with a signal line 4 for transmitting a data signal (referred to as video signal) indicating information such as video and characters (referred to as video information) to the pixel 1. Scanning lines 5A and 5B for controlling on / off (driving) of the switching elements, and thin film silicon 6 for applying a video signal transmitted to the signal line 4 to the transparent electrode 3 or the reflective electrode 2 , 7, 8 and the auxiliary capacity wiring 9 for forming the auxiliary capacity are formed. The auxiliary capacitance is for stabilizing the drive potential of the pixel 1, and an auxiliary capacitance for the reflective electrode 2 and an auxiliary capacitance for the transparent electrode 3 are configured.

  The scanning line 5 </ b> A is a scanning line for the transparent electrode 3 and is formed across the transmission portions 13 of the plurality of pixels 1. The scanning line 5 </ b> B is a scanning line for the reflective electrode 2, and is formed across the reflective portions 12 of the plurality of pixels 1. A signal line 4 is formed beside the transmission part 13 and the reflection part 12 so as to intersect the scanning lines 5A and 5B. A thin film transistor (TFT) 10A is formed in a region where the scanning line 5A and the signal line 4 intersect, and a thin film transistor 10B is formed in a region where the scanning line 5B and the signal line 4 are orthogonal to each other. ing.

  The thin film transistor 10 </ b> A is formed below the signal line 4. Furthermore, the thin film transistor 10 </ b> A is provided in a region adjacent to the transparent electrode 3. The thin film transistor 10 </ b> B is formed below the signal line 4. Further, the thin film transistor 10B is provided in the vicinity of the boundary between the reflective electrode 2 and the transparent electrode of the pixel adjacent to the pixel 1. In the present embodiment, the signal line 4 is formed so as to overlap the transparent electrode 3 and the reflective electrode 2 of the adjacent pixel 1.

  The thin film silicon (transparent electrode thin film silicon) 6 is connected to the signal line 4 by a thin film transistor 10A and a thin film transistor contact 11A. The thin film silicon 6 is connected to the transparent electrode 3 and the transmissive electrode contact 14A through the auxiliary capacitance in which the auxiliary capacitance wiring 9 is formed.

  The thin film silicon (reflective electrode thin film silicon) 7 is an area where the thin film transistor 10B is formed, and is connected by the signal line 4 and the thin film transistor contact 11B, and is connected by the reflective electrode 2 and the reflective electrode contact 14B. Yes. A thin film silicon 8 is formed in the auxiliary capacitance in which the auxiliary capacitance wiring 9 of the reflective electrode 2 is formed, and is connected to the reflective electrode 2 and the thin film silicon 7 by a reflective electrode contact 14B. The scanning line 5A is a region where the thin film transistor 10A is formed in the stacked structure, and is formed between the signal line 4 and the thin film silicon 6, and the scanning line 5B is a region where the thin film transistor 10B is formed. Thus, it is formed between the signal line 4 and the thin film silicon 7. In the thin film transistors 10A and 10B of the pixel 1, the source / drain directions are formed in opposite directions.

  Here, in this embodiment, one of thin film silicons forming a thin film transistor, which is connected to a signal line, may be referred to as a source electrode and the other may be referred to as a drain electrode.

(2. Cross-sectional explanation of pixel)
Next, a cross-sectional structure of the pixel 1 will be described with reference to FIG. 2 is a cross-sectional view taken along line AA ′ in FIG.

  As shown in FIG. 2, the pixel 1 includes a thin film transistor substrate 20 on which thin film transistors 10A and 10B are formed (see FIG. 1), and a counter substrate 30 disposed to face the thin film transistor substrate 20 with the liquid crystal layer 40 interposed therebetween. Prepare.

  In the thin film transistor substrate 20, a passivation film 22 is formed on the upper layer of the transparent substrate 21, and an interlayer insulating film 23 is formed on the upper layer of the passivation film 22. In addition, the reflective electrode 2 and the transparent electrode 3 are disposed on the interlayer insulating film 23 with a gap therebetween. The region where the reflective electrode 2 is formed is the reflective portion 12, and the region where the transparent electrode 3 is formed is the transmissive portion 13.

  In the middle layer of the interlayer insulating film 23, the reflective electrode scanning line 5B, the auxiliary capacitance wiring 9, and the transmissive electrode scanning line 5A are arranged side by side (in a horizontal direction with respect to the film surface) at intervals. ing. That is, the reflective electrode scanning line 5B, the auxiliary capacitance line 9, and the transmissive electrode scanning line 5A are formed in the same layer. The reflective electrode scanning line 5B and the transmissive electrode scanning line 5A are formed with the auxiliary capacitance wiring 9 interposed therebetween.

  The reflection electrode scanning line 5 </ b> B and the auxiliary capacitance line 9 are formed below the reflection electrode 2. The transmissive electrode scanning line 5 </ b> A is formed below the transparent electrode 3. Further, the thin film silicon 8 and the thin film silicon 6 are juxtaposed below the storage capacitor wiring 9 with a space therebetween. The thin film silicon 8 and the thin film silicon 6 are formed in contact with the passivation film 22.

  The thin film silicon 8 and the reflective electrode 2 are connected via a reflective electrode contact 14B. That is, a silicon layer reflective electrode wiring 24 is formed on the upper layer of the thin film silicon 8, and a silicon layer metal interlayer contact (mediation layer) 25 is formed on the upper layer. A region where the silicon layer metal interlayer contact 25 and the reflective electrode 2 are connected is a reflective electrode contact 14B.

  Similarly, the thin film silicon 6 and the transparent electrode 3 are connected via a transmission electrode contact 14A. A silicon layer transmissive interelectrode wiring 26 is formed in the upper layer of the thin film silicon 6, and a silicon layer metal interlayer contact (mediation layer) 27 is formed in the upper layer. A region where the silicon layer metal interlayer contact 27 and the transparent electrode 3 are connected is a transmissive electrode contact 14A. The silicon layer metal interlayer contacts 25 and 27 are formed in the same layer as the signal line 4 (not shown in FIG. 2).

  In the counter substrate 30, a color filter 32 is formed below the transparent substrate 31 (on the side where the thin film transistor substrate 20 is disposed), and a transparent electrode 33 is further formed below the color filter 32. A liquid crystal layer 40 is formed between the thin film transistor substrate 20 and the counter substrate 30. A backlight (not shown) is formed below the transparent substrate 21 of the thin film transistor substrate 20.

(3. Description of thin film transistor)
Next, a cross-sectional view of the thin film transistor 10A will be described with reference to FIG. Note that the description of the thin film transistor 10B is omitted because it is the same.

  FIG. 3 is a cross-sectional view taken along line B-B ′ in FIG. 1.

  The thin film transistor 10A is formed below the signal line 4, and includes a contact 11A, a partial region of the thin film silicon 6, and a scanning line 5A. The drain terminal of the thin film transistor 10A and the thin film silicon formed in the auxiliary capacitor are connected as the thin film silicon 6.

  As described above, the passivation film 22 is formed on the upper layer of the transparent substrate 21, and the thin film silicon 6 is formed on the upper layer. An interlayer insulating film 23 is formed above the thin film silicon 6, and a signal line 4 is formed above the interlayer insulating film 23. As described above, the signal line 4 is formed in the same layer as the silicon layer metal interlayer contacts 25 and 27 shown in FIG. A scanning line 5 </ b> A is formed in the middle layer of the interlayer insulating film 23. The signal line 4 and the thin film silicon 6 are connected by a contact 11A.

  Thereby, the scanning line 5A functions as a gate, and when the voltage of the scanning line 5A is increased (turned on), the video signal transmitted to the signal line 4 is transmitted to the thin film silicon 6 through the contact 11A. Thereby, the thin film silicon 6 functions as a channel. That is, the video signal transmitted to the thin film silicon 6 as the drain of the thin film transistor 10A is applied to the transparent electrode 3 from the transmissive electrode contact 14A through the auxiliary capacitance.

  In the present embodiment, the thin film transistors 10A and 10B are formed below the signal lines 4. However, the thin film transistors 10A and 10B are formed below the reflective electrode 2 or below the scanning lines 5A and 5B. It may be. These configurations will be described later.

(4. Operation explanation)
As described above, the pixel 1 includes the thin film transistor 10 </ b> A for driving the transparent electrode 3 and the thin film transistor 10 </ b> B for driving the reflective electrode 2. Since the transparent electrode 3 and the reflective electrode 2 are not directly connected, driving can be controlled independently by each of the thin film transistors 10A and 10B. For this reason, when reflective display is performed in a bright place or the like, only the reflective electrode 2 can be driven without driving the transparent electrode 3. Conversely, when transmissive display is performed in a dark place or the like, only the transparent electrode 3 can be driven without driving the reflective electrode 2. For this reason, since only the electrode to be driven can be driven, it is not necessary to apply an extra voltage to the electrode. Thereby, a low power consumption liquid crystal display device can be provided.

  The thin film transistors 10 </ b> A and 10 </ b> B are formed below the signal line 4. For this reason, light from a backlight (not shown) is not blocked by the thin film transistors 10A and 10B, and the transmittance does not decrease. That is, it is possible to form the thin film transistors 10A and 10B that can control the drive of the transparent electrode 3 and the reflective electrode 2 independently while suppressing the decrease in the aperture ratio.

  In FIG. 1, the scanning line 5 </ b> A is formed in the transmissive portion 13, but the area for blocking the light emitted from the backlight is much smaller than when a thin film transistor is disposed in the transmissive portion. That's it. That is, in this embodiment, even if the scanning line 5A is formed in the transmissive portion 13, a thin film transistor is provided for each of the reflective electrode portion 205 and the transparent electrode portion 204 described in the prior art (3) (see FIG. 15). The aperture ratio can be improved as compared with the case where 203A and 203B are arranged.

  As described above, according to the configuration of the pixel 1, the pixel 1 having the configuration provided with the auxiliary capacitor has a high aperture ratio, high visibility in a bright place and a dark place, high-quality display, and low power consumption. A liquid crystal display device can be realized.

  Further, in the pixel 1, as shown in FIG. 2, the thickness of the liquid crystal layer 40 of the transmission part 13 is equal to the thickness of the liquid crystal layer 40 of the reflection part 12. That is, in the pixel 1, the distance from the transparent electrode 3 to the counter substrate 30 is equal to the distance from the reflective electrode 2 to the counter substrate 30.

  For this reason, as shown in FIG. 4, the light transmission path is different between the transmission unit 13 and the reflection unit 12. FIG. 4 is an explanatory diagram for explaining a difference in light transmission path between the transmission unit 13 and the reflection unit 12 in the pixel 1.

  When performing transmissive display, light from a backlight formed below the thin film transistor substrate 20 is transmitted through the transparent electrode 3, the liquid crystal layer 40, and the color filter 32 and emitted above the counter substrate 30 in the transmissive portion 13. The For this reason, the number of times that the light emitted from the counter substrate 30 passes through the liquid crystal layer 40 and the color filter 32 is one.

  On the other hand, in the case of performing reflective display, light is incident from the counter substrate 30 side in the reflective portion 12, passes through the color filter 32 and the liquid crystal layer 40, and is reflected by the reflective electrode 2. Then, the light again passes through the liquid crystal layer 40 and the color filter 32 and is emitted above the counter substrate 30. Thus, the liquid crystal layer 40 and the color filter 32 are passed twice.

  Further, for example, when the pixel 1 is applied to a transmissive LCD (TLCD) in a VA (Vertical alignment) LC mode, the light transmission path of the reflection unit 12 is twice that of the light transmission path of the transmission unit 13. Therefore, the reflected light emitted from the reflecting portion 12 undergoes a two-fold retardation change as compared to the transmitted light emitted from the transmitting portion 13. That is, the rate of change in the luminance of the reflection unit 12 is twice as fast as the rate of change in the luminance of the transmission unit 13 (see Patent Document 3).

  This will be described with reference to FIG. FIG. 5 is a graph showing the luminance characteristics of the pixel 1 when performing transmissive display and when performing reflective display.

  The horizontal axis of the graph shown in FIG. 5 represents the voltage applied to the pixel 1. The vertical axis represents the luminance normalized by the maximum luminance of each of the transmission unit 13 and the reflection unit 12.

  As shown in FIG. 5, the normalized luminance peak position is different between the transmissive portion 13 and the reflective portion 12, and the normalized luminance peak position in the transmissive portion 13 is normalized in the reflective portion 12. The voltage is higher than the position of the luminance peak. That is, the rate of change in the luminance of the light emitted from the reflection unit 12 and the rate of change in the luminance of the light in the transmission unit 13 are not uniform.

  Here, as described above, according to the configuration of the pixel 1 of the liquid crystal display device according to the present embodiment, the thin film transistor 10A that controls the driving of the transparent electrode 3 and the thin film transistor 10B that controls the driving of the reflective electrode 2 are formed. Therefore, a voltage can be applied to each of the transparent electrode 3 and the reflective electrode 2 independently.

  In the present embodiment, among the video signals input to the signal line 4, the liquid crystal display according to the present embodiment is related to the transparent electrode video signal (first data signal) transmitted to the transmissive electrode 3. The voltage change of the transparent electrode video signal with respect to the video signal input to the apparatus and the reflective electrode video signal (second data signal) transmitted to the reflective electrode 2 among the video signals input to the signal line 4. The γ curve is made different due to the difference in voltage change.

  As described above, the voltage change of the video signal for the transparent electrode with respect to the video signal input to the signal line 4 by modulating the video signal input to the liquid crystal display device according to the present embodiment, and the signal line 4 The voltage applied to the transmissive electrode 3 and the reflective electrode 2 is changed to an appropriate voltage by changing the voltage change of the reflective electrode video signal with respect to the input video signal. Thereby, a difference in optical characteristics between the transmission unit 13 and the reflection unit 12 can be made difficult to appear with respect to the video signal input to the signal line 4.

  In other words, by changing the γ curve (γ characteristics) between the transparent electrode video signal and the reflective electrode video signal, an optimal image is displayed in both the dark and bright areas. Accordingly, the contrast can be adjusted.

  In the present embodiment, the video signal input to the liquid crystal display device according to the present embodiment is modulated by a circuit unit (not shown) for controlling the voltage applied to the liquid crystal layer 40. That is, the video signal input to the signal line 4 is a signal modulated by the circuit unit.

  Accordingly, for example, even when transmissive display is performed, the visibility can be improved by increasing the contrast of the reflecting portion 12 or the like.

  That is, when transmissive display is performed, the color tone of light emitted from the pixel 1 can be adjusted by applying a voltage to the transparent electrode 3 and also applying a voltage to the reflective electrode 2 in an auxiliary manner. it can. For this reason, even when transmissive display is performed, the voltage applied to the reflective electrode 2 can be adjusted according to the use environment of the liquid crystal display device including the pixels 1 to improve the visibility. When performing reflective display, a voltage may be applied to the reflective electrode 2 and a voltage may be applied to the transparent electrode 3 as an auxiliary.

  Thus, since the pixel 1 can have different γ curves in the transmissive part 13 and the reflective part 12, it is suitable for a bright place and a dark place, that is, in a use environment of the liquid crystal display device including the pixel 1. Appropriate visibility can be obtained.

  Further, by forming color filters of different tones in the regions corresponding to the transmissive portion 13 and the reflective portion 12 in the color filter 32, different γ characteristics can be realized in the transmissive portion 13 and the reflective portion 12. .

  That is, for example, when the color filter 32 made of red, blue, and green is used, the color filter 32 is composed of a total of six colors including the red, blue, and green color filters for the transmission portion 13 and the red, blue, and green color filters for the reflection portion 12. A color filter 32 is used.

  In a bright place, in order to increase the maximum luminance of the light emitted from the reflection unit 12, the color filter 32 formed in the reflection unit 12 is compared with the color filter 32 formed in the transmission unit 13. Use one with high transmittance. The color filter 32 formed on the reflection unit 12 sets the γ characteristic for the reflection unit 12 in order to improve the visibility of the light emitted from the reflection unit 12.

  Furthermore, as described above, in the pixel 1, the distance from the transparent electrode 3 to the counter substrate 30 is equal to the distance from the reflective electrode 2 to the counter substrate 30 (see FIG. 2).

  For this reason, the number of times the light emitted above the counter substrate 30 is transmitted through the liquid crystal layer 40 is different between the transmission unit 13 and the reflection unit 12, and the rate of change in luminance of the light emitted from the reflection unit 12 is Even if the ratio of the change in the luminance of the light of the transmissive part 13 is not uniform, the video signal input to the liquid crystal display device according to the present embodiment is modulated to be suitable for the transmissive electrode 3 and the reflective electrode 2. If a large voltage is applied, the optical characteristics can be made equal without adjusting the film thickness between the liquid crystal layer 40 of the transmissive portion 13 and the liquid crystal layer 40 of the reflective portion 12. That is, it is not necessary to adjust the thickness of the liquid crystal layer 40, such as forming a transparent resin on the reflective portion 12 in order to make the optical characteristics of the liquid crystal of the liquid crystal layer 40 equal between the transmissive portion 13 and the reflective portion 12.

  Therefore, it is possible to make the display speed of video information and the like constant in the transmissive display and the reflective display while simplifying the manufacturing of the counter substrate 30.

  Furthermore, before applying a desired voltage for transmitting a video signal to the pixel 1 to the transparent electrode or the reflective electrode, a voltage larger or smaller than the desired voltage is applied, and then the desired voltage is applied. When performing the overshoot drive to be applied, since the liquid crystal layer 40 has the same thickness in the transmissive part 13 and the reflective part 12, the response speed of the liquid crystal layer 40 is equal, and the overshoot drive waveform applied to the transparent electrode 3 The overshoot drive waveform applied to the reflective electrode 2 can be matched. For this reason, adjustment of the overshoot drive waveform applied to each of the transparent electrode 3 and the reflective electrode 2 is simplified. Thereby, it is possible to provide a liquid crystal display device that can easily reproduce a moving image that requires a high response speed of the liquid crystal layer 40 with high quality.

(5. Modification 1)
Next, a first modification of the pixel 1 shown in FIG. 1 will be described with reference to FIGS.

  FIG. 6 is a plan view illustrating a configuration of the pixel 50 according to the present embodiment.

  FIG. 7 is a cross-sectional view taken along line C-C ′ in FIG. 6.

  The formation position of the scanning line 5 </ b> A for the transparent electrode 3 is different between the pixel 50 and the pixel 1.

  As shown in FIG. 7, the scanning line 5A of the pixel 50 is formed between the auxiliary capacitance (region where the auxiliary capacitance wiring 9 is formed) and the transmissive electrode contact 14A. Further, the scanning line 5 </ b> A is formed across the plurality of pixels 50 below the transparent electrode 3, the reflective electrode 2, the gap portion, and the reflective electrode 2 that are arranged at intervals.

  As shown in FIG. 7, the thin film silicon 57 is formed in the upper layer of the passivation film 22 and is juxtaposed with the thin film silicon 6. The thin film silicon 57 is formed from below the auxiliary capacitance line 9 to below the transparent electrode 52 of the pixel adjacent to the pixel 50. The thin film silicon 57 formed below the transparent electrode 52 is provided with a silicon layer reflective electrode wiring (second contact) 58, and a silicon layer metal interlayer contact (mediation layer) 59 is formed thereon. Is formed.

  The silicon layer metal interlayer contact 59 is formed from below the transparent electrode 52 to above the auxiliary capacitance line 9. Further, the silicon layer metal interlayer contact 59 and the reflective electrode 2 are connected to each other above the auxiliary capacitance line 9 by a reflective electrode contact (first contact) 14B.

  That is, the silicon layer transmission electrode wiring 26 and the silicon layer reflection electrode wiring 58 are formed with the scanning line 5A, the auxiliary capacitance wiring 9, and the scanning line 5B interposed therebetween. The scanning line 5A is formed below the gap between the transparent electrode 3 and the reflective electrode 2 and below the reflective electrode 2, and the auxiliary capacitance line 9 is formed below the reflective electrode 2, and the scanning line 5B. Are formed below the reflective electrode 2 and the gap between the reflective electrode 2 and the transparent electrode 52. The scanning line 5B is formed between the reflective electrode contact 14B and the silicon layer inter-reflective electrode wiring 58 in a plan view region.

  With such a configuration, the scanning line 5 </ b> A may not be formed below the transparent electrode 3. Thereby, the light from the backlight is not blocked by the scanning line 5 </ b> A in the transmissive portion 13. Therefore, the aperture ratio of the transmission part 13 can be improved as compared with the pixel 1.

  Further, the reflective electrode 2 and the thin film silicon 57 are connected across the scanning line 5 </ b> B and the auxiliary capacitance wiring 9. Therefore, it is not necessary to form the inter-silicon-layer inter-electrode wiring 58 for connecting the reflective electrode 2 and the thin film silicon 57 between the scanning line 5B and the auxiliary capacitance wiring 9. For this reason, it is possible to reduce the gap between the scanning line 5B and the auxiliary capacitance wiring 9, and it is possible to realize a high aperture ratio while forming the scanning line 5B under the reflective electrode 2. .

(6. Modification 2)
Next, a third modification of the pixel 1 shown in FIG. 1 will be described with reference to FIG.

  FIG. 8 is a plan view illustrating the configuration of the pixel 70 according to the present embodiment.

  The formation position of the thin film transistor is different between the pixel 70 and the pixel 1. That is, in the pixel 70, the thin film transistor 10E for the reflective electrode 2 is formed below the reflective electrode 2.

  As shown in FIG. 8, the scanning line 5B is formed in the middle layer of the reflective electrode 2 and the thin film silicon 7B via the interlayer insulating film 23 (see FIG. 2) in the region of the reflective electrode 2 in plan view. The second gate electrode 5D functions as a second gate electrode. The second gate electrode 5D is a partial region of the scanning line 5B, and is formed so as to be orthogonal to the thin film silicon 7B via the interlayer insulating film 23 (see FIG. 2).

  The thin film silicon 7B is connected to the signal line 4 by a thin film transistor contact 11B, and is connected to the reflective electrode 2 by a reflective electrode contact 14B. The thin film silicon 7B does not intersect the scanning line 5B, and intersects only the second gate electrode 5D below the reflective electrode 2. As described above, the region where the thin film silicon 7B and the second gate electrode 5D intersect below the reflective electrode is the thin film transistor 10E, and the second gate electrode 5D functions as the gate electrode of the thin film transistor 10E.

  With the above configuration, a configuration in which the thin film transistor 10E is formed below the reflective electrode can be realized.

  Since the thin film silicon 10A for the transparent electrode 3 is formed below the signal line 4 similarly to the pixel 1 (see FIG. 1), it is possible to suppress a decrease in the aperture ratio.

  Further, in the low power consumption mode when only the thin film transistor 10E is operated, the transmission distance of the signal between the signal line 4, the reflective electrode 2 and the thin film silicon 8 is shortened by shortening the length of the thin film silicon 7B. For this reason, the resistance value between the signal line 4 and the reflective electrode 2 and the thin film silicon 8 can be reduced. Thereby, it is possible to reduce the load of the video signal transmitted from the signal line 4 to the reflective electrode 2 and to further reduce the power consumption.

(7. Modification 3)
Next, a third modification that is a modification of the pixel 50 shown in FIG. 6 will be described with reference to FIG.

  FIG. 9 is a plan view illustrating a configuration of the pixel 80 according to the present embodiment. The pixel 80 is different from the pixel 50 in that the thin film transistor 10F for the transparent electrode 3 and the thin film transistor 10G for the reflective electrode 2 are formed below the reflective electrode 2 and further below the scanning lines 5A and 5B. .

  As shown in FIG. 9, thin film silicon (transparent electrode thin film silicon) 8 </ b> A and thin film silicon 8 </ b> B are formed below the auxiliary capacity wiring 9 in the auxiliary capacity in which the auxiliary capacity wiring 9 is formed. The thin film silicon 8A is connected to the transparent electrode 3 by the transmissive electrode contact 14A through the thin film silicon 81. The thin film silicon 6C is connected to the signal line 4 via the contact 11A. The thin film silicon 6 </ b> C is formed below the scanning line 5 </ b> A in parallel with the scanning line 5 </ b> A and the auxiliary capacitance line 9, and is connected to the thin film silicon 81. Thus, the region where the thin film silicon 6C is formed below the scanning line 5A is the thin film transistor 10F for the transparent electrode 3. With the above configuration, the thin film transistor 10F can be formed below the reflective electrode 2 and further below the scanning line 5A.

  The thin film silicon 8B includes thin film silicon 82 formed below the scanning line 5B and intersecting with the scanning line 5B. The thin film silicon 82 and the silicon layer metal interlayer contact 59 formed above the scanning line 5B and crossing the scanning line 5B are connected via the silicon layer reflective electrode wiring 58. The silicon layer metal interlayer contact 59 and the reflective electrode 2 are connected via a reflective electrode contact 14B. That is, the scanning line 5B is sandwiched between the thin film silicon 82 and the silicon layer metal interlayer contact 59 via the interlayer insulating film 23 (see FIG. 7).

  The thin film silicon 7C is connected to the signal line 4 through the contact 11B. The thin film silicon 7C is formed below the scanning line 5B in parallel with the scanning line 5B and the auxiliary capacitance line 9, and is connected to the thin film silicon 82. Thus, the region where the thin film silicon 7C is formed below the scanning line 5B is the thin film transistor 10G for the reflective electrode 2. With the configuration described above, the thin film transistor 10G can be formed below the reflective electrode 2 and further below the scanning line 5B.

  Further, the pixel 80 has a transparent electrode video signal transmission path transmitted from the signal line 4 to the transparent electrode 3 and a transparent electrode transmitted from the signal line 4 to the reflective electrode 2 as compared with the pixel 50 (see FIG. 6). The transmission path for video signals is short. That is, since the effective resistance value for transmitting the transparent electrode video signal and the transparent electrode video signal can be kept low, power consumption can be reduced.

(8. Modification 4)
Next, a fourth modification of the pixel 1 shown in FIG. 1 will be described with reference to FIGS. 10 and 11.

  FIG. 10 is a plan view illustrating a configuration of the pixel 90 according to the present embodiment. The pixel 90 is different from the pixel 1 in that a thin film transistor 10H for the transparent electrode 3 and a thin film transistor 10I for the reflective electrode 2 are formed below the reflective electrode 2.

  FIG. 11 is a cross-sectional view taken along line D-D ′ in FIG. 10.

  As shown in FIGS. 10 and 11, the scanning line 5 </ b> A intersects with the signal line 4 and is formed below the transparent electrode 3. In addition, the scanning line 5A includes a second gate electrode 5C and a third gate electrode 5E that is arranged in parallel with the second gate electrode 5C and functions as a third gate electrode. The thin film silicon 6D intersects the second gate electrode 5C and the third gate electrode 5E below the reflective electrode 2. As described above, the region where the thin film silicon 6D, the second gate electrode 5C, and the third gate electrode 5E intersect under the reflective electrode 2 is the thin film transistor 10H.

  The thin film silicon 8A is connected to a silicon layer metal interlayer contact (mediation layer) 91 via a silicon layer transparent interelectrode wiring (fourth contact) 14C provided below the reflective electrode 2. The silicon layer metal interlayer contact 91 intersects the scanning line 5A via the interlayer insulating film 23 below the transparent electrode 3, and is connected to the transparent electrode 3 via a transmission electrode contact (third contact) 14A. . Thus, the thin film silicon 8A is connected to the transparent electrode 3.

  The scanning line 5 </ b> B intersects with the signal line 4 and is formed below the transparent electrode 52. The scanning line 5B includes a second gate electrode 5D and a third gate electrode 5F that is arranged in parallel with the second gate electrode 5D and functions as a third gate electrode. The thin film silicon 7D is connected to the signal line 4 via the contact 11B. Further, the thin film silicon 7D is connected to the thin film silicon 8B, and is connected to the reflective electrode 2 through the silicon layer reflective electrode wiring 24, the silicon layer metal interlayer contact 25, and the reflective electrode contact 14B. The thin film silicon 7D intersects the second gate electrode 5D and the third gate electrode 5F below the reflective electrode 2. As described above, the region where the second gate electrode 5D and the third gate electrode 5F intersect below the reflective electrode 2 is the thin film transistor 10I. With the above configuration, the thin film transistor 10H and the thin film transistor 10I can be formed below the reflective electrode 2.

  The thin film transistor 10H has the second gate electrode 5C and the third gate electrode 5E, and the thin film transistor 10I has the second gate electrode 5D and the third gate electrode 5F. The amount of current of 10I can be reduced, and the accuracy of holding the video signal can be increased.

  Further, it is not necessary to provide the thin film silicon 8A below the scanning line 5A. For this reason, the silicon layer metal interlayer contact 91 is formed in a layer between the scanning line 5A and the transparent electrode 3, and the transparent electrode 3 and the thin film silicon 8A can be connected. As a result, the load of the scanning line 5A, the transparent electrode contact 14A, and the silicon layer metal are compared with the case where the thin film silicon for the transparent electrode is formed below the scanning line and the signal line and the transparent electrode are connected. The loads on the interlayer contact 91 and the silicon layer transparent interelectrode wiring 14C can be reduced.

(9. Reference example)
Next, a fifth modification of the pixel 1 shown in FIG. 1 will be described with reference to FIG.

  FIG. 12 is a plan view illustrating a configuration of the pixel 60 according to the reference example.

  The formation position of the thin film transistor is different between the pixel 60 and the pixel 1. That is, in the pixel 60, the thin film transistor 10C for the transparent electrode 3 is formed below the signal line 4 and the transparent electrode 3, and the thin film transistor 10D for the reflective electrode 2 is formed below the signal line 4 and the reflective electrode 2. Yes.

  As shown in FIG. 12, the scanning line 5 </ b> A is formed in the middle layer of the transparent electrode 4 and the thin film silicon 6 via the interlayer insulating film 23 (see FIG. 2) in the region of the transparent electrode 4 in plan view. It has the 2nd gate electrode 5C which functions as a 2nd gate electrode. The second gate electrode portion 5C is a partial region of the scanning line 5A, and is formed so as to be orthogonal to the thin film silicon 6 via the interlayer insulating film 23 (see FIG. 2).

  Further, in the region of the reflective electrode 2 in plan view, the scanning line 5B is formed in the middle layer of the reflective electrode 2 and the thin film silicon 7 via the interlayer insulating film 23 (see FIG. 2), and the second gate electrode The second gate electrode 5D functioning as The second gate electrode 5D is a partial region of the scanning line 5B, and is formed so as to be orthogonal to the thin film silicon 7 via the interlayer insulating film 23 (see FIG. 2).

  That is, the thin film transistor 10 </ b> C for applying a video signal to the transparent electrode 3 is formed below the signal line 4 and the transparent electrode 4. A thin film transistor 10 </ b> D for applying a video signal to the reflective electrode 2 is formed below the signal line 4 and the reflective electrode 2.

  In the auxiliary capacitor in which the auxiliary capacitor wiring 9 is formed, the thin film silicon 8A for the transparent electrode 3 and the thin film silicon 8B for the reflective electrode 2 are formed. The thin film silicon 8A is connected to the transparent electrode 3 by the transmissive electrode contact 14A. Further, the thin film silicon 8B is connected to the reflective electrode 2 by a reflective electrode contact 14B.

  Thereby, in the thin film transistor 10C, a region below the signal line 4 and orthogonal to the thin film silicon 6 of the scanning line 5A functions as a gate electrode, and below the transparent electrode 4 and below the second gate electrode 5C. A region orthogonal to the thin film silicon 6 also functions as a gate electrode.

  Further, in the thin film transistor 10D, a region below the signal line 4 and orthogonal to the thin film silicon 7 of the scanning line 5B functions as a gate electrode, and is below the reflective electrode 2 and is a thin film of the second gate electrode 5D. A region orthogonal to the silicon 7 also functions as a gate electrode.

  According to this, the current amount of the thin film transistors 10C and 10D can be reduced during the video signal holding period, and the accuracy of holding the video signal can be improved.

  The thin film transistor 10C is formed below the signal line 4 and the transparent electrode 4. For example, as in the pixel 200 shown in FIG. 16, the thin film transistor for the transparent electrode is formed only in the region where the transparent electrode is formed. Compared with the case where it does, it becomes possible to suppress the fall of the aperture ratio of the permeation | transmission part 13. FIG.

  Note that the thin film transistor 10C may be the thin film transistor 10A formed only below the signal line 4 as described above.

  The present invention is not limited to the above-described embodiments and modifications, and various modifications can be made within the scope shown in the claims, and technical means disclosed in each of the above-described embodiments can be appropriately used. Embodiments obtained in combination are also included in the technical scope of the present invention.

  Switching elements are provided separately for transmissive display and reflective display, and further switching elements are provided below the signal lines, reflective electrodes, or scanning lines, so that a reduction in aperture ratio can be suppressed and pixels with high visibility can be formed. In addition to being applicable to liquid crystal display devices, it can be suitably applied to a wide variety of display devices.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention and is a plan view illustrating a configuration of a pixel according to a liquid crystal display device of the present invention. The AA 'sectional view taken on the line shown in FIG. 1 is represented. FIG. 2 is a cross-sectional view taken along line B-B ′ shown in FIG. 1. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention, and is an explanatory diagram illustrating a difference in optical path between a transmissive portion and a reflective portion of a pixel according to a liquid crystal display device of the present invention. It is a graph showing the luminance characteristic of the transmissive part and reflective part of the pixel. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention and is a plan view illustrating a configuration of a first modification of a pixel according to a liquid crystal display device of the present invention. FIG. 7 is a cross-sectional view taken along line C-C ′ in FIG. 6. FIG. 5 is a plan view illustrating a configuration of a second modification example of a pixel according to the liquid crystal display device of the present invention, showing an embodiment of the present invention. FIG. 11 is a plan view illustrating a configuration of a third modification example of the pixel according to the liquid crystal display device of the present invention, showing an embodiment of the present invention. FIG. 11 is a plan view illustrating a configuration of a fourth modification example of the pixel according to the liquid crystal display device of the present invention, showing an embodiment of the present invention. It is D-D 'arrow sectional drawing of FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an embodiment of the present invention and is a plan view illustrating a configuration of a reference example of a pixel according to a liquid crystal display device of the present invention. It is a top view showing the prior art and showing the structure of the pixel of a liquid crystal display device. FIG. 14 is a cross-sectional view taken along line E-E ′ shown in FIG. 13. 14 is a graph for explaining a difference in luminance between transmissive display and reflective display of the pixel shown in FIG. 13. It is a top view showing the prior art and showing the structure of the pixel of a liquid crystal display device.

Explanation of symbols

1, 50, 60, 70, 80, 90 Pixel 2 Reflective electrode 3 Transparent electrode 4 Signal line 5A / 5B Scan line 5C / 5D Second gate electrode 6 Thin film silicon (thin film silicon for transparent electrode)
7 Thin film silicon 8 Thin film silicon (thin film silicon for reflective electrodes)
8A thin film silicon (thin film silicon for transparent electrodes)
8B thin film silicon (thin film silicon for reflective electrodes)
9, 9A, 9B Auxiliary capacitance wiring 10, 10A, 10B, 10C, 10D Thin film transistor 10E, 10F, 10G, 10H, 10I Thin film transistor 11A, 11B Contact 12 Reflection portion 13 Transmission portion 14A Transmission electrode contact (transmission electrode contact, first contact) 3 contacts)
14B Reflective electrode contact (first contact)
14C Silicon layer transparent interelectrode wiring (fourth contact)
DESCRIPTION OF SYMBOLS 20 Thin-film transistor substrate 21 Transparent substrate 22 Passivation film 23 Interlayer insulation film 24 Silicon layer reflective electrode wiring 25, 27 Silicon layer metal interlayer contact 26 Silicon layer transparent electrode wiring 57 Thin film silicon (Thin film silicon for reflective electrodes)
58 Silicon layer reflective electrode wiring (second contact)
59 Silicon layer metal interlayer contact (mediation layer)
91 Silicon layer metal interlayer contact (mediation layer)

Claims (12)

In a display device including a first substrate provided with a switching element that controls driving of a pixel serving as a display unit,
The first substrate includes
A transparent electrode for controlling the luminance of light transmitted through the pixel;
A reflective electrode that is juxtaposed with the transparent electrode and controls reflection of light incident on the pixel;
A signal line for transmitting a data signal to the transparent electrode and the reflective electrode;
A scanning line arranged to intersect the signal line and controlling the driving of the switching element;
An auxiliary capacitance wiring for forming an auxiliary capacitance for stabilizing the potential of the pixel,
The auxiliary capacitance wiring is provided below the reflective electrode,
As the switching element, there are provided a transparent electrode switching element that controls driving of the transparent electrode, and a switching element for reflecting electrode that is different from the transparent electrode switching element and controls driving of the reflecting electrode. And
The transparent electrode switching element and the reflective electrode switching element are provided below the signal line, below the reflective electrode, or below the scanning line. The scanning line is
A transparent electrode scanning line for controlling the driving of the transparent electrode switching element;
A reflective electrode scanning line for controlling driving of the reflective electrode switching element,
The transparent electrode scanning line and the reflective electrode scanning line include a first gap between the transparent electrode and the reflective electrode, a reflective electrode, and a pixel different from the pixel adjacent to the reflective electrode and the reflective electrode. 2, and is formed in a region in plan view of the first gap, the reflective electrode, and the second gap. Display device.   The display device according to claim 1, wherein the transparent electrode scanning line, the reflective electrode scanning line, and the auxiliary capacitance wiring are formed in the same layer.   4. The display device according to claim 1, wherein the transparent electrode scanning line and the reflective electrode scanning line are formed with the auxiliary capacitance wiring interposed therebetween. 5. Below the auxiliary capacitance wiring, the transparent electrode thin film silicon constituting the auxiliary capacitance for the transparent electrode and the reflective electrode thin film silicon constituting the auxiliary capacitance for the reflective electrode are juxtaposed,
5. The connection between the transparent electrode and the thin film silicon for transparent electrode and the connection between the reflective electrode and the thin film silicon for reflective electrode are made through an intermediate layer. The display device according to any one of the above. A first contact connecting the reflective electrode and the mediating layer;
A second contact for connecting the intermediate layer and the reflective electrode thin film silicon is provided,
The display device according to claim 5, wherein the second contact is formed below a transparent electrode of a different pixel adjacent to the pixel. A third contact connecting the transparent electrode and the mediation layer;
A fourth contact is provided for connecting the mediation layer and the transparent electrode thin film silicon;
The display device according to claim 5, wherein the fourth contact is formed below the reflective electrode.   The display device according to claim 1, wherein a γ curve is different between a region corresponding to the transparent electrode and a region corresponding to the reflective electrode in the pixel. Among the data signals, regarding the first data signal transmitted to the transparent electrode, a voltage change of the first data signal with respect to an input signal input to the display device;
Among the data signals, regarding the second data signal transmitted to the reflective electrode, the voltage change of the second data signal with respect to the input signal input to the display device is different, so that the γ curve is different. The display device according to claim 8. A display device according to any one of claims 1 to 9, a liquid crystal layer, and a second substrate disposed opposite to the first substrate across the liquid crystal layer,
The liquid crystal display device, wherein the thickness of the liquid crystal layer between the transparent electrode and the second substrate is equal to the thickness of the liquid crystal layer between the reflective electrode and the second substrate. A color filter is formed in a region corresponding to the pixel on the second substrate;
The liquid crystal display device according to claim 10, wherein a color tone is different between a region facing the transparent electrode portion and a region facing the reflective electrode portion of the color filter.   When a voltage for displaying information on the pixel is applied to the transparent electrode or the reflective electrode, a voltage larger or smaller than a voltage for displaying information on the pixel is applied, and then the information is applied to the pixel. The liquid crystal display device according to claim 11, wherein a voltage for displaying is applied.

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