JP5104023B2 - Electro-optical device and electronic apparatus - Google Patents

Description

  The present invention relates to a technical field of an electro-optical device such as a liquid crystal device having a touch panel function, and an electronic apparatus including such an electro-optical device.

  In a liquid crystal device which is an example of this type of electro-optical device, an optical sensor is disposed for each of a plurality of pixel units or for a group of an arbitrary number of pixel units as a group, and an image by transmitted light transmitted through the pixel units. There has been proposed a liquid crystal device having a so-called touch panel function that enables input of information to the liquid crystal device through display and instruction means (see, for example, Patent Documents 1 to 4). In such a liquid crystal device, it is detected by a light receiving element such as an optical sensor that an instruction means such as a finger or an indicator member has touched the display surface of the liquid crystal device or moved on the display surface. Information can be entered.

  In such an electro-optical device, when the periphery of the instruction unit is bright, the shadow of the instruction unit that approaches or touches the display surface is identified as a bright area around the display unit, so that the image of the instruction unit is displayed. Identified. On the other hand, in such an electro-optical device, when the surroundings of the instruction means are dark, the image of the instruction means is specified by detecting the detection light reflected by the instruction means such as a finger separately from outside light. (For example, see Patent Document 5). Further, the reflected light reflected by the pointing means such as a finger is detected when the brightness of the image displayed on the display surface is low and when the brightness is high, and the difference between the reflected lights is obtained. A technique for specifying a position has also been proposed (see, for example, Patent Document 6).

  On the other hand, for a liquid crystal device that does not have a touch panel function, a technique for improving the display quality of an image by inserting a black image has been proposed (see, for example, Patent Document 7).

JP-A-5-333369 JP-A-6-18846 Japanese Patent Laid-Open No. 6-194681 JP 2004-45875 A JP 2006-317682 A JP 2004-318819 A JP 2006-30741 A

  However, in a liquid crystal device which is an example of this type of electro-optical device, when detecting a shadow of an instruction unit that blocks outside light with a backlight as a light source turned off, for example, in an environment where outside light is weak such as at night Below, since the light intensity of the outside light that is not blocked by the instruction means is originally low, it becomes difficult to distinguish and detect the shadow of the instruction means from other parts.

  In addition, in this type of liquid crystal device, a method of detecting the indication means by reflecting the light emitted from the backlight by the indication means and detecting the reflected light by a light detection means such as an optical sensor can be considered. In an environment where the light intensity of the reflected light and the external light is approximately the same, it is difficult to distinguish and detect the pointing means from other parts.

  In addition, in an environment where the intensity of external light is high, the amount of light that wraps around between the pointing means and the image display surface increases, so that light is detected by a light sensor arranged in the contact area of the display surface where the pointing means contacts. The ratio between the detected signal and the signal detected by the optical sensor arranged in the non-contact area where the indicating means did not contact is small, and it is difficult to distinguish and detect the indicating means from other parts. It is.

  Therefore, the present invention has been made in view of the above problems and the like. For example, an electric device having a touch panel function capable of reliably detecting an instruction means such as a finger indicating a display surface regardless of the light intensity of external light. It is an object to provide an optical device and an electronic apparatus including such an electro-optical device.

  In order to solve the above problems, an electro-optical device according to the present invention includes a substrate, a plurality of pixel portions formed on the substrate and constituting a display area of a display surface indicated by an instruction unit, and the display A black image is displayed on the display surface at one timing of the display period for displaying an image on the screen, and another image having a higher brightness than the black image is displayed at another timing of the display period. And a control means for controlling the plurality of pixel portions, and an optical sensor portion formed in the display area on the substrate.

  According to the electro-optical device according to the present invention, the substrate is, for example, a TFT array substrate on which pixel switching elements such as TFTs are provided in a pixel unit described later.

  The plurality of pixel portions are arranged in a matrix, for example, so as to constitute a display region on the substrate. A display surface on which a desired image is displayed by driving each of the plurality of pixel portions is configured to be instructed by an instruction unit such as a finger.

  The control means is, for example, a control circuit unit that controls operations of various circuit units such as a data line driving circuit unit that supplies an image signal to each pixel unit or a scanning line driving circuit unit that supplies a scanning signal to the pixel unit. , An external circuit unit electrically connected to the circuit unit or to each circuit unit. Under the control of such a control means, the plurality of pixel units display a black image on the display surface at one timing of the display period for displaying an image on the display surface, and a black image at another timing of the display period. Display other images with higher brightness. Each of these black images and other images is displayed with a uniform brightness in accordance with each image in the display area on the display surface. In other words, light having a uniform light intensity with different luminance is emitted from the display surface toward the instruction means at one timing of the display period and at another timing of the display period.

  The optical sensor unit is formed in the display area on the substrate. Accordingly, the optical sensor unit detects external light that is not blocked by the instruction unit at one timing, and detects reflected light that is reflected from the display surface by the instruction unit at another timing. . Since the black image and other images are displayed on the display surface at regular intervals or at irregular intervals, the indication means can be detected even when the light intensity of external light changes. More specifically, for example, when the light intensity of the external light applied to the periphery of the electro-optical device is low, that is, when the periphery is dark, another image having higher brightness than the black image is displayed on the display surface. At another timing, the optical sensor unit can detect the indication means while distinguishing it from other parts by detecting the reflected light reflected by the indication means. On the other hand, when the light intensity of outside light is high, that is, when the surroundings are bright, at one timing, the light sensor unit detects the outside light not blocked by the pointing means, thereby shadowing the pointing means. It becomes possible to detect, and the position of the pointing means can be specified based on the position of the shadow.

  Therefore, according to the electro-optical device according to the present invention, it is possible to reliably detect an instruction unit such as a finger indicating the display surface without being influenced by the light intensity of the external light. An electro-optical device having a touch panel function capable of inputting information can be provided.

  In one aspect of the electro-optical device according to the invention, the other image may be a blue image displayed on the display surface by emitting blue light from the display region.

  According to this aspect, blue light is less likely to be recognized by human vision than other color lights such as red light and green light. Therefore, for example, when a moving image is displayed by an image displayed on the display surface according to each of successive frames, a black image and a blue image are partially inserted into these frames. Therefore, according to this aspect, it is possible to detect the instruction unit while preventing the black image and the blue image from being visually recognized.

  In another aspect of the electro-optical device according to the invention, the electro-optical device further includes a light source disposed on the opposite side of the display surface as viewed from the substrate, and the light source is turned off at the one timing and the other timing is provided. It may be turned on.

  According to this aspect, at one timing and at another timing, the light emitted toward the instruction unit can be adjusted according to the turning on and off of the light source, and the instruction unit can be reliably operated even when the intensity of the external light changes. It can be detected.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device of the present invention.

  Since the electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention, a cellular phone, an electronic notebook, a word processor, a monitor direct-view video tape recorder, a work capable of high-quality display are provided. Various electronic devices such as a station, a videophone, a POS terminal, and a touch panel can be realized. In addition, as an electronic apparatus according to the present invention, for example, an electrophoretic device such as electronic paper can be realized.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

  Hereinafter, embodiments of an electro-optical device and an electronic apparatus according to the present invention will be described with reference to the drawings. Hereinafter, a liquid crystal device will be described as an example of the electro-optical device according to the invention.

<1: Liquid crystal device>
<1-1: Overall Configuration of Liquid Crystal Device>
First, the overall configuration of the liquid crystal device 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the liquid crystal device 1 as seen from the counter substrate side together with the components formed on the TFT array substrate, and FIG. 2 is a cross-sectional view taken along the line II-II ′ of FIG. The liquid crystal device 1 according to the present embodiment is driven by a TFT active matrix driving method with a built-in driving circuit.

  1 and 2, in the liquid crystal device 1, a TFT array substrate 10, which is an example of the “substrate” of the present invention, and a counter substrate 20 are disposed to face each other. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are sealed regions located around the image display region 10a, which is a display region in which a plurality of pixel portions are provided. Are adhered to each other by a sealing material 52 provided on the surface.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. In the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance (inter-substrate gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed.

  A light-shielding frame light-shielding film 53 that defines the frame area of the image display area 10a is provided on the counter substrate 20 side in parallel with the inside of the seal area where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side. There is a peripheral area located around the image display area 10a. In other words, particularly in the present embodiment, when viewed from the center of the TFT array substrate 10, the distance from the frame light shielding film 53 is defined as the peripheral region.

  A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in a region located outside the sealing region in which the sealing material 52 is disposed in the peripheral region. The scanning line driving circuit 104 is provided along two sides adjacent to the one side so as to be covered with the frame light shielding film 53. Further, in order to connect the two scanning line driving circuits 104 provided on both sides of the image display region 10 a in this way, a plurality of the pixel lines are covered along the remaining side of the TFT array substrate 10 and covered with the frame light shielding film 53. Wiring 105 is provided.

  In the peripheral region on the TFT array substrate 10, a sensor control circuit unit 201 for controlling a sensor unit including an optical sensor described later is formed. The external circuit connection terminal 102 is connected to a connection terminal provided on a flexible substrate (hereinafter referred to as FPC) 200 which is an example of a connection means for electrically connecting the external circuit and the liquid crystal device 1. The backlight included in the liquid crystal device 1 is controlled by a backlight control circuit 202 configured by an IC circuit or the like mounted on the FPC 200. Each of the sensor control circuit unit 201 and the backlight control circuit 202 may be built in the liquid crystal device 1 or formed outside the liquid crystal device 1.

  Vertical conductive members 106 functioning as vertical conductive terminals between the two substrates are disposed at the four corners of the counter substrate 20. On the other hand, the TFT array substrate 10 is provided with vertical conduction terminals in a region facing these corner portions. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

  In FIG. 2, on the TFT array substrate 10, an alignment film is formed on the pixel electrode 9a after the pixel switching TFT, the scanning line, the data line and the like are formed. On the other hand, on the counter substrate 20, in addition to the counter electrode 21, a lattice-shaped or striped light-shielding film 23 and an alignment film are formed on the uppermost layer portion. The liquid crystal layer 50 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state between the pair of alignment films. The image displayed by the liquid crystal device 1 is displayed on the display surface 20 s on the side of the opposite substrate 20 that does not face the liquid crystal layer 50. In the present embodiment, illustration of the polarizing plate and the color filter is omitted for convenience of explanation, but when the polarizing plate and the color filter are arranged on the counter substrate 20, the liquid crystal device is shown in the drawing. The top surface of 1 becomes the display surface.

  The liquid crystal device 1 includes a backlight 206 disposed below the TFT array substrate 10 in the drawing. The backlight 206 is an example of the “light source” in the present invention, and is disposed on the back side of the display surface 20s. The backlight 206 is configured by planarly arranging semiconductor light emitting elements of a point light source, which is an example of a light emitting diode. The backlight 206 may include a light emitting diode such as an organic EL element. Further, a sidelight type backlight that emits light from a light source arranged on a side surface by a light guide in a planar shape may be used.

  1 and 2, on the TFT array substrate 10, in addition to the drive circuits such as the data line drive circuit 101 and the scanning line drive circuit 104, the image signal on the image signal line is sampled to obtain data. Sampling circuit that supplies lines, precharge circuit that supplies pre-charge signals of a predetermined voltage level to multiple data lines in advance of image signals, inspection of quality, defects, etc. of the electro-optical device during production or shipment An inspection circuit or the like may be formed.

<1-2: Circuit Configuration of Liquid Crystal Device>
Next, the circuit configuration of the liquid crystal device 1 will be described with reference to FIGS. 3 and 4. FIG. 3 is a block diagram illustrating a main circuit configuration of the liquid crystal device 1, and FIG. 4 is a block diagram illustrating a detailed circuit configuration of the sensor control circuit unit 201.

  3 and 4, the liquid crystal device 1 includes a sensor control circuit unit 201, a backlight control circuit unit 202, a display control circuit unit 203 which is an example of the “control unit” of the present invention, and the “photosensor unit” of the present invention. For example, a sensor unit 204, a display unit 205, and a backlight 206 are provided.

  The display unit 205 includes a plurality of pixel units formed in the image display region 10 a on the TFT array substrate 10. The display control circuit unit 203 includes the scanning line driving circuit 104 and the data line driving circuit 101, and the display unit 205 displays images corresponding to various signals including image signals supplied from the external circuit unit 207. The operation of the display unit 205 is controlled as possible. The sensor unit 204 is formed in the image display region 10 a on the TFT array substrate 10 together with the display unit 205.

  The sensor control circuit unit 201 controls the operation of the sensor unit 204 and supplies a signal for changing the light intensity of the light source light emitted from the backlight 206 to the backlight control circuit unit 202.

  Here, a detailed configuration of the sensor control circuit unit 201 will be described with reference to FIG. As shown in FIG. 4, the sensor control circuit unit 201 includes an image processing circuit unit 201a and a memory 201b. The image processing circuit unit 201a processes data of an image captured by the instruction unit when the instruction unit such as a finger is detected. The memory 201b stores data supplied from the image processing circuit unit 201a. The image processing circuit unit 201a reads the data stored in the memory 201b in a timely manner and uses the data to specify the position of the instruction unit.

  In FIG. 3 again, the backlight control circuit unit 202 controls the operation of the backlight 206 based on signals supplied from the external circuit unit 207 and the sensor control circuit unit 201, respectively. Under the control of the backlight control circuit unit 202, the backlight 206 emits light source light for detecting that an instruction unit such as a finger indicates the display surface 20s of the liquid crystal device 1 to the display surface 20s.

  The backlight 206 is also used as a display light source that emits display light for displaying an image corresponding to an image signal supplied from the external circuit unit 207 via the backlight control circuit unit 202 on the display surface.

  Therefore, as the light source light for detecting the instruction means, a signal different from the image signal supplied to each pixel unit for displaying a desired image in the image display region 10a is supplied to the pixel unit or the light source. As a result, the light is emitted from the display surface 20S toward the instruction unit. In addition, such light source light is inserted into a series of consecutive frames that display a desired image in the image display area 10a. Black images are also inserted into these series of frames.

  In addition, according to the backlight 206, since it is not necessary to provide the light source for emitting the detection light for detecting an instruction | indication means separately, the structure of the liquid crystal device 1 can be simplified.

<1-3: Configuration of Pixel Unit>
Next, the configuration of the pixel portion of the liquid crystal device 1 will be described in detail with reference to FIGS. FIG. 5 is an equivalent circuit of various elements, wirings, and the like in a plurality of pixels formed in a matrix forming the image display region 10a of the liquid crystal device 1. FIG. 6 shows an equivalent circuit of the sensor unit 204 together with the pixel unit. It is the equivalent circuit shown. FIG. 7 is a plan view of a plurality of adjacent pixel groups on the TFT array substrate on which data lines, scanning lines, pixel electrodes and the like are formed. 8 is a cross-sectional view taken along the line VIII-VIII ′ of FIG. 9 is a cross-sectional view taken along the line IX-IX ′ of FIG. In FIGS. 8 and 9, the scale of each layer / member is different for each layer / member to have a size that can be recognized on the drawing.

  In FIG. 5, each of a plurality of pixel portions 72 formed in a matrix that forms the image display region 10a of the liquid crystal device 1 includes a sub-pixel portion 72R that displays red, a sub-pixel portion 72G that displays green, and blue Is included. Therefore, the liquid crystal device 1 is a display device that can display a color image. Each of the sub-pixel portions 72R, 72G, and 72B includes a pixel electrode 9a, a TFT 30, and a liquid crystal element 50a. The TFT 30 is electrically connected to the pixel electrode 9a, and performs switching control of the pixel electrode 9a when the liquid crystal device 1 operates. The data line 6a to which the image signal is supplied is electrically connected to the source of the TFT 30. The image signals S1, S2,..., Sn to be written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. May be.

  The scanning line 3a is electrically connected to the gate of the TFT 30, and the liquid crystal device 1 sequentially applies the scanning signals G1, G2,..., Gm to the scanning line 3a in a pulse sequence in this order at a predetermined timing. It is comprised so that it may apply. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and the image signal S1, S2,... Supplied from the data line 6a is closed by closing the switch of the TFT 30 serving as a switching element for a certain period. Sn is written at a predetermined timing. Image signals S1, S2,..., Sn written to the liquid crystal via the pixel electrode 9a are held for a certain period with the counter electrode formed on the counter substrate.

  The liquid crystal contained in the liquid crystal layer 50 modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In the normally white mode, the transmittance for incident light decreases according to the voltage applied in units of each sub-pixel unit. In the normally black mode, the voltage applied in units of each sub-pixel unit. Accordingly, the transmittance for incident light is increased, and light having a contrast corresponding to an image signal is emitted from the liquid crystal device 1 as a whole. The storage capacitor 70 is added in parallel with the liquid crystal element 50a formed between the pixel electrode 9a and the counter electrode in order to prevent the image signal from leaking.

  In FIG. 6, the sensor unit 204 is formed for each pixel unit 72 in the image display region 10 a on the TFT array substrate 10, and includes TFTs 211 a, 211 b and 211 c, a photodiode 212, and a capacitor 213. Yes.

  The gate of the TFT 211 a is electrically connected to the sensor precharge control line 302. Each of the source and drain of the TFT 211a is electrically connected to the precharge line 301, the photodiode 212, and the capacitor 213.

  The TFT 211 a is switched on and off in accordance with a precharge control signal supplied from the sensor control circuit unit 201 via the sensor precharge control line 302. The photodiode 212 is precharged by a precharge voltage supplied via the precharge line 301 and the TFT 211a.

  The gate of the TFT 211b is electrically connected to the photodiode 212, and is an amplification element that amplifies a change in the amount of charge stored in the photodiode 212. The change in the amount of charge generated in the photodiode 212 is caused by light detected by the photodiode 212.

  The gate of the TFT 211 c is electrically connected to the sensor output control line 303. The TFT 211c is turned on / off in accordance with an output control signal supplied via the sensor output control line 303, and an output signal corresponding to a change in the amount of charge generated in the photodiode 212 is sensor-controlled via the sensor output line 304. Output to the circuit unit 201.

  Next, a specific configuration of the sub-pixel unit 72s that forms the pixel unit will be described with reference to FIGS. In the following, the main configuration of the pixel unit that displays each of the black image and the blue image at a predetermined timing in the position detection method of the instruction means described later, and the display surface 20s when each of the black image and the blue image is displayed. The configuration of the photodiode 212 for detecting light incident on the TFT will be described in detail, and the components of the pixel portion and the specifics of the semiconductor elements such as TFTs 211a, 211b, and 211c formed in the same layer as or different from the photodiode 212 are described. A typical configuration is omitted. The semiconductor element such as the TFT 211a is formed in a non-opening region that separates the opening regions of the respective pixel portions from each other so that light that passes through the opening region of the pixel portion is not irradiated, like the TFT 30.

  7 and 8, on the TFT array substrate 10 of the liquid crystal device 1, a plurality of transparent pixel electrodes 9a (contours are indicated by dotted line portions 9a ') in a matrix in the X and Y directions. The data lines 6a and the scanning lines 3a are provided along the vertical and horizontal boundaries of the pixel electrode 9a. An instruction unit such as a finger can input various information to the liquid crystal device 1 by touching the display surface 20 s of the liquid crystal device 1 or instructing a desired region of the display surface 20 s.

  The scanning line 3a is arranged so as to face the channel region 1a ′ indicated by the hatched region rising to the right in FIG. 7 in the semiconductor layer 1a. A pixel switching TFT 30 is provided at each of the intersections of the scanning line 3a and the data line 6a.

  The data line 6 a is formed on the base film 42 aa formed using the second interlayer insulating film 42 whose upper surface is flattened as a base, and is connected to the high concentration source region of the TFT 30 through the contact hole 81. Yes. The data line 6a and the inside of the contact hole 81 are made of, for example, an Al (aluminum) -containing material such as Al—Si—Cu or Al—Cu, Al alone, or a multilayer film including an Al layer and a TiN layer. The data line 6a has a function of shielding the TFT 30 from light.

  The storage capacitor 70 includes a lower capacitor electrode 71 as a pixel potential side capacitor electrode connected to the high concentration drain region 1e and the pixel electrode 9a and a part of the upper capacitor electrode 300 as a fixed potential side capacitor electrode. It is formed by being opposed to each other through the film 75.

  As shown in FIGS. 7 and 8, the upper capacitor electrode 300 is provided on the upper side of the TFT 30 as an upper light shielding film (built-in light shielding film) containing, for example, a metal or an alloy. The upper capacitor electrode 300 also functions as a fixed potential side capacitor electrode. The upper capacitor electrode 300 is, for example, at least one of metals such as Ti (titanium), Cr (chromium), W (tungsten), Ta (tantalum), Mo (molybdenum), Pd (palladium), and Al (aluminum). The upper capacitor electrode 300 includes, for example, a first film made of a conductive polysilicon film and a metal silicide containing a refractory metal. It may have a multilayer structure in which a second film made of a film or the like is laminated.

  The lower capacitor electrode 71 is made of, for example, a conductive polysilicon film or a simple metal, an alloy, a metal silicide, including at least one of metals such as Ti, Cr, W, Ta, Mo, Pd, and Al. It consists of polysilicide, a laminate of these, etc., and functions as a pixel potential side capacitor electrode. The lower capacitor electrode 71 functions as a pixel potential side capacitor electrode, and functions as another example of a light absorption layer or an upper light shielding film disposed between the upper capacitor electrode 300 as the upper light shielding film and the TFT 30. Furthermore, the pixel electrode 9a and the high-concentration drain region 1e of the TFT 30 have a function of relay connection. However, the lower capacitive electrode 71 may also be composed of a single layer film or a multilayer film containing a metal or an alloy, like the upper capacitive electrode 300.

  The dielectric film 75 disposed between the lower capacitor electrode 71 and the upper capacitor electrode 300 as a capacitor electrode is, for example, a silicon oxide film such as an HTO (High Temperature Oxide) film, an LTO (Low Temperature Oxide) film, or a nitride. It is composed of a silicon film or the like.

  The upper capacitor electrode 300 extends from the image display region 10a where the pixel electrode 9a is disposed to the periphery thereof, and is electrically connected to a constant potential source to be a fixed potential.

  The lower light-shielding film 11a provided in a grid pattern below the TFT 30 via the base insulating film 12 shields the channel region 1a ′ of the TFT 30 and its surroundings from the return light that enters the device from the TFT array substrate 10 side. To do. Similar to the upper capacitor electrode 300, the lower light-shielding film 11a includes, for example, at least one of metals such as Ti, Cr, W, Ta, Mo, Pd, and Al, a simple metal, an alloy, a metal silicide, It is made of polysilicide or a laminate of these.

  In addition to the function of interlayer insulating the TFT 30 from the lower light-shielding film 11a, the base insulating layer 12 is formed on the entire surface of the TFT array substrate 10, thereby remaining rough after polishing the surface of the TFT array substrate 10 or after cleaning. It has a function of preventing deterioration of the characteristics of the pixel switching TFT 30 due to dirt or the like. The pixel electrode 9a is electrically connected to the high concentration drain region 1e in the semiconductor layer 1a through the contact holes 83 and 85 by relaying the lower capacitor electrode 71.

  As shown in FIGS. 7 and 8, the liquid crystal device 1 includes a transparent TFT array substrate 10 and a transparent counter substrate 20 disposed to face the TFT array substrate 10. The TFT array substrate 10 is made of, for example, a quartz substrate, a glass substrate, or a silicon substrate, and the counter substrate 20 is made of, for example, a glass substrate or a quartz substrate.

  A pixel electrode 9a is provided on the TFT array substrate 10, and an alignment film 16 that has been subjected to a predetermined alignment process such as a rubbing process is provided above the pixel electrode 9a. For example, the pixel electrode 9a is made of a transparent conductive film such as an ITO (Indium Tin Oxide) film, and the alignment film 16 is made of an organic film such as a polyimide film.

  A counter electrode 21 is provided on the entire surface of the counter substrate 20, and an alignment film 22 subjected to a predetermined alignment process such as a rubbing process is provided below the counter electrode 21. The counter electrode 21 is made of a transparent conductive film such as an ITO film. The alignment film 22 is made of an organic film such as a polyimide film.

  The counter substrate 20 may be provided with a lattice-shaped or striped light-shielding film. By adopting such a configuration, together with the upper light shielding film provided as the upper capacitor electrode 300, it is more reliable to prevent the incident light from entering the channel region 1a ′ or its periphery from the TFT array substrate 10 side. Can be prevented.

  A liquid crystal layer 50 is formed between the TFT array substrate 10 and the counter substrate 20 that are configured as described above and are arranged so that the pixel electrode 9a and the counter electrode 21 face each other. The liquid crystal layer 50 takes a predetermined alignment state by the alignment films 16 and 22 in a state where an electric field from the pixel electrode 9a is not applied.

  In FIG. 8, the pixel switching TFT 30 has an LDD (Lightly Doped Drain) structure, and includes a gate electrode 3a2, a channel region 1a ′ of the semiconductor layer 1a in which a channel is formed by an electric field from the scanning line 3a, and a scanning line. An insulating film 2 including a gate insulating film that insulates 3a from the semiconductor layer 1a, a low concentration source region 1b and a low concentration drain region 1c, a high concentration source region 1d, and a high concentration drain region 1e are provided. The low-concentration source region 1b, the low-concentration drain region 1c, the high-concentration source region 1d, and the high-concentration drain region 1e constitute an impurity region of the semiconductor layer 1a and are formed in mirror symmetry on both sides of the channel region 1a ′. Yes.

  The gate electrode 3a2 is composed of a conductive film such as a polysilicon film or a simple metal, an alloy, a metal silicide, a poly, including at least one of metals such as Ti, Cr, W, Ta, Mo, Pd, and Al. It is formed of silicide, a laminate of these, and the like, and is provided on the channel region 1a ′ via the insulating film 2 so as not to overlap the low concentration source region 1b and the low concentration drain region 1c. Therefore, in the TFT 30, the offset between the high concentration source region 1d and the high concentration drain region 1e and the gate electrode 3a2 is sufficiently secured.

  Note that the edge of the gate electrode 3a2 overlaps the boundary between the lightly doped source region 1b and the lightly doped drain region 1c and the channel region 1a ′ in plan view, and the lightly doped source region 1b and the lightly doped drain region 1c The parasitic capacitance generated between the gate electrode 3a2 and the gate electrode 3a2 is reduced. As a result, the TFT 30 transistor can operate at high speed, and the display performance of the liquid crystal device 1 is enhanced.

  In addition, in the liquid crystal device 1, the low-concentration source region 1 b and the low-concentration drain are effectively provided by the upper capacitor electrode 300 formed on the gate electrode 3 a 2 so as to cover the TFT 30 as compared with the case where the light is shielded only by the gate electrode 3 a 2. The region 1c can be shielded from light.

  As described above, according to the liquid crystal device 1, it is possible to reduce defects caused when displaying an image such as flicker using the TFT 30 with reduced light leakage current, and to display an image with high quality. In addition, since the TFT 30 has an LDD structure, the off-current flowing through the low-concentration source region 1b and the low-concentration drain region 1c is reduced when the TFT 30 is not operating, and the on-current flowing when the TFT 30 is operating is reduced. Is suppressed. Therefore, according to the liquid crystal device 1, it is possible to display an image with high quality by utilizing the advantage of the LDD structure and the fact that light leakage current hardly flows.

  On the lower light-shielding film 11a, a first interlayer insulating film 41 is formed in which a contact hole 81 leading to the high concentration source region 1d and a contact hole 83 leading to the high concentration drain region 1e are opened.

  A lower capacitor electrode 71 and an upper capacitor electrode 300 are formed on the first interlayer insulating film 41, and a second interlayer insulating film 42 in which contact holes 81 and 85 are respectively formed is formed thereon. ing.

  The second interlayer insulating film 42 in the present embodiment is made of, for example, a BPSG film, and the upper surface is flattened through a fluidized state by heating. That is, a step is formed on the upper surface during the film formation due to the existence of the storage capacitor 70, the TFT 30, the scanning line 3a, and further the base light shielding film 11a on the lower layer side. The unevenness due to the steps is leveled. The second interlayer insulating film 42 may be reduced in level using a photosensitive acrylic resin or the like.

  Further, a third interlayer insulating film 43 in which contact holes 85 are formed is formed of, for example, a BPSG film so as to cover the entire surface of the second interlayer insulating film 42 from above the data line 6a. The pixel electrode 9 a and the alignment film 16 are provided on the upper surface of the third interlayer insulating film 43. The third interlayer insulating film 42 may be reduced in level using a photosensitive acrylic resin or the like.

  Next, the photodiode 212 will be described in detail with reference to FIGS.

  As shown in FIGS. 7 and 9, the photodiode 212 is formed in a non-opening region in the image display region 10a that substantially separates open regions that contribute to image display. The opening area is an area through which display light emitted from the backlight 206 is transmitted. Such an opening region is surrounded by a non-opening region where a non-permeable film such as the data line 6a is formed. In the opening region, the display light emitted from the backlight 206 is modulated according to the alignment state of the liquid crystal layer 50 and is emitted from the display surface 20s as modulated light.

  The photodiode 212 detects the reflected light and the external light reflected by the pointing means that is in contact with the display surface 20s or located on the display surface 20s. The sensor control circuit unit 201 specifies the position of the instruction unit based on the light intensity of each of the reflected light and the external light detected by the photodiode 212. The photodiode 212 is a PIN diode in which a lower electrode 212e, an N-type semiconductor layer 212d, a light receiving layer 212c, a P-type semiconductor layer 212b, and an upper electrode 212a are sequentially stacked from the TFT array substrate 10 side. Since the photodiode 212 is disposed in a non-opening region that does not contribute to image display, the photodiode 212 does not decrease the aperture ratio of the pixel and does not hinder image display according to the operation of each pixel unit. A recess 152 is formed in a portion of the third interlayer insulating film 43 that extends to the non-opening region. The light receiving surface 212 s of the photodiode 212 faces the bottom surface of the recess 152. The counter substrate 20 is formed with a black matrix 153 that partially defines a non-opening region. The photodiode 212 may be formed in the horizontal direction in the same layer as the TFT 30. By forming the photodiode 212 and the TFT 30 in the same layer, the process for forming each of these elements can be shared, and the process can be simplified as compared with the case where these elements are formed by separate processes.

<2: Method for detecting instruction means>
Next, a detection method in which the liquid crystal device 1 detects the instruction unit will be described with reference to FIGS. FIG. 10 is a conceptual diagram showing the relationship between a series of frame images constituting a moving image displayed on the display surface 20s.

  As shown in FIG. 10, on the display surface 20s, driving of each pixel unit is controlled under the control of the display control circuit unit 203, and an image is displayed by a series of consecutive frames (Nth frame to N + 5th frame in the figure). Gn, Gn + 1, Gn + 2, Gn + 3, Gn + 4, Gn + 5 are displayed. Here, the image Gn + 1 is a black image in which black is uniformly displayed on the image portion of the entire display surface 20s, and the image Gn + 4 is a blue image in which blue is uniformly displayed on the pixel portion of the entire display surface 20s. It is. The images Gn, Gn + 2, Gn + 3, and Gn + 5 are images constituting an image such as a moving image to be displayed on the display surface 20s according to the image signal. The image Gn + 4 has higher brightness than the image Gn + 1. Therefore, the image Gn + 1 which is a black image is displayed in the (N + 1) th frame which is an example of the “one timing” in the present invention among a series of consecutive frames, and the N + 4th which is an example of the “other timing” in the present invention. In the frame, an image Gn + 4, which is an example of the “other image” of the present invention, is displayed.

  In the (N + 1) th frame, the sensor unit 204 detects outside light that is not blocked by the instruction unit that instructs the display surface 20s. The sensor unit 204 detects reflected light obtained by reflecting the blue light emitted from the display surface 20s by the instruction unit in the (N + 4) th frame.

  Therefore, according to the liquid crystal device 1, even when the light intensity of the external light changes, the instruction unit can be detected by the light detected by the sensor unit 204 in any one of the (N + 1) th frame and the (N + 4) th frame.

  Here, with reference to FIG. 10 to FIG. 12, the principle that the indication means can be detected even when the light intensity of outside light changes will be described in detail. 11 and 12 are lists showing the intensity of light detected in the touch part and the non-touch part with respect to the intensity of external light. Table 1 shows a light detection state in a state where the backlight is turned on, that is, a state where light is emitted uniformly from the display surface 20s, and Table 2 shows that the backlight is turned off. The state of light detection in a state where light is not emitted from the display surface 20s is shown. 11 and 12 show the intensity of light reflected by the instruction unit when the display surface 20s is instructed by the instruction unit, and the non-touch part is not blocked by the instruction unit. Indicates the light intensity of outside light.

  In Table 1, since the light intensity detected in each of the touch part and the non-touch part is different in the conditions 1 and 3, the instruction means can be detected. However, in the condition 2, in the touch part and the non-touch part, respectively. Since the detected light intensities are equal, they cannot be detected separately from other parts of the indicating means. In Table 2, as in Table 1, the indication means cannot be detected in Condition 6.

  Therefore, as shown in FIG. 10, according to the liquid crystal device 1 according to the present embodiment, the image Gn + 1 that is a black image and the image Gn + 4 that is a blue image are displayed at different timings. it can. More specifically, in the condition 2 in Table 1 shown in FIG. 11, the shadow of the instruction means can be detected under the condition 5 in Table 2 by displaying the image Gn + 1. It can be detected by identifying the part. On the other hand, in condition 6 in Table 2 shown in FIG. 12, the reflected light reflected by the instruction means under the condition 3 in Table 1 can be detected by displaying the image Gn + 4. It can be detected by identifying the part.

  Therefore, according to the liquid crystal device 1 according to the present embodiment, even when the light intensity of outside light changes, it is possible to detect an instruction unit such as a finger that indicates the display surface 20s, and the detected unit through the detected instruction unit Various information can be reliably input to the liquid crystal device 1.

  In addition, in this embodiment, since a blue image that is hard to be detected by other color lights is inserted into a series of frame images, there is an advantage that the display quality of a moving image displayed by the series of frame images is not deteriorated. .

<3: Electronic equipment>
Next, an embodiment of an electronic apparatus including the above-described liquid crystal device will be described with reference to FIGS.

  FIG. 13 is a perspective view of a mobile personal computer to which the above-described liquid crystal device is applied. In FIG. 13, a computer 1200 includes a main body 1204 provided with a keyboard 1202 and a liquid crystal display unit 1206 including the above-described liquid crystal device. The liquid crystal display unit 1206 is configured by adding a backlight to the back surface of the liquid crystal panel 1005, and has a touch panel function that can input information reliably even when the light intensity of external light changes.

  Next, an example in which the above-described liquid crystal device is applied to a mobile phone will be described. FIG. 14 is a perspective view of a mobile phone which is an example of the electronic apparatus of the present embodiment. In FIG. 14, a mobile phone 1300 includes a liquid crystal device 1005 that adopts a reflective display format and has the same configuration as the above-described liquid crystal device, along with a plurality of operation buttons 1302. According to the mobile phone 1300, information can be accurately input via the display surface by an instruction means such as a finger.

It is a top view of the liquid crystal device concerning this embodiment. It is II-II 'sectional drawing of FIG. It is the block diagram which showed the main circuit structures of the liquid crystal device which concerns on this embodiment. It is the block diagram which showed the detailed circuit structure of the sensor control circuit part. 3 is an equivalent circuit in an image display region of the liquid crystal device according to the present embodiment. It is the equivalent circuit which showed the equivalent circuit of the sensor part with the pixel part. FIG. 5 is a plan view of a plurality of pixel groups adjacent to each other on a TFT array substrate on which data lines, scanning lines, pixel electrodes and the like are formed. It is VIII-VIII 'sectional drawing of FIG. It is IX-IX 'sectional drawing of FIG. It is the conceptual diagram which showed the relationship of a series of frame images which comprise the moving image displayed on a display surface. It is the list | surface (the 1) which showed the intensity | strength of the light detected in a touch part and a non-touch part with respect to the intensity | strength of external light. It is the table | surface (the 2) which showed the intensity | strength of the light detected in a touch part and a non-touch part with respect to the intensity | strength of external light. It is the perspective view which showed an example of the electronic device which concerns on this embodiment. It is the perspective view which showed the other example of the electronic device which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal device, 10 ... TFT array substrate, 72 ... Pixel part, 203 ... Display control circuit part, 204 ... Sensor part

Claims (3)

A substrate,
A plurality of pixel portions that are formed on the substrate and constitute a display area of a display surface indicated by the instruction means;
A black image and a blue image are displayed at different timings of the display period for displaying the image on the display surface,
When the black image is displayed, the shadow of the instruction means is detected,
When the blue image is displayed, the reflected light reflected by the instruction means is detected.
An electro-optical device. A light source disposed on the opposite side of the display surface as viewed from the substrate;
The light source is turned off at the one timing and turned on at the other timing.
The electro-optical device according to claim 1. To claim 1 or 2 that has provided an electro-optical device according,
An electronic device characterized by that.

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