JP4791108B2 - Image display device - Google Patents

Description

  The present invention relates to an image display device with a built-in optical sensor, such as a liquid crystal display with a built-in touch sensor using an optical sensor.

  An active matrix liquid crystal display device in which a touch sensor that senses that the user touches the screen is built in the pixel does not need to be mounted outside the panel. Therefore, there are many advantages such as a reduction in the thickness of the entire module. As this touch sensor, for example, an optical sensor is employed.

  In FIG. 2 of the following Non-Patent Document 1, a phototransistor for a photosensor as a photo TFT and a phototransistor from a photosensor as a readout TFT are provided in the region of one of the pixels such as R, G, and B. A touch sensor built-in type liquid crystal display provided with a signal reading transistor is shown. In this liquid crystal display, a signal readout wiring is connected as a readout to the source (or drain) of the readout TFT. The signal readout wiring Readout is provided adjacent to the data wiring Data.

  In addition to Non-Patent Document 1, there is the following as prior art document information related to the invention of this application.

JP 10-90655 A Willem den Boer et al. `` 56.3: Active Matrix LCD with Integrated Optical Touch Screen '' SID 2003 DIGEST, pp.1494-1497

  In Non-Patent Document 1, the signal readout wiring Readout is provided in parallel adjacent to the data wiring Data. Therefore, the potential fluctuation in the data wiring easily affects the signal on the signal readout wiring, and the signal detection sensitivity is easily lowered. That is, since the signal readout wiring of the optical sensor is arranged adjacent to and parallel to the data wiring, noise from the data wiring causes a decrease in sensor sensitivity due to the capacitance between the wirings.

  Also in Patent Document 1, the signal line 31 connected to the display transistor 27 and the signal line 32 connected to the photoelectric conversion element transistor 28 are adjacently provided in parallel in FIG. Yes. Therefore, the problem of the influence of the potential fluctuation in the data wiring on the signal on the signal readout wiring may occur as in the case of Non-Patent Document 1.

  Moreover, in the said nonpatent literature 1, an optical sensor is arrange | positioned only to one specific pixel (for example, B pixel) among each pixels, such as R, G, and B, and adjacent pixels (for example, R pixel and G pixel) The photo TFT constituting the optical sensor and the readout TFT for signal readout are not formed. For this reason, the aperture ratio of the pixel (for example, B pixel) in which the photosensor is disposed is small, and the aperture ratio of the pixel (for example, R pixel and G pixel) in which the photosensor is not disposed is large. Therefore, a difference in luminance is likely to occur between a pixel (for example, a B pixel) where a photosensor is disposed and a pixel (for example, an R pixel and a G pixel) where no photosensor is disposed. If there is a luminance difference between pixels, display unevenness is likely to occur.

  In this case, in order to prevent the occurrence of a difference in luminance, the aperture ratio of pixels (for example, R pixels and G pixels) where no photosensor is arranged is matched with the aperture ratio of pixels (for example, B pixels) where the photosensor is arranged. There is nothing else. However, in that case, the brightness of the entire display is lowered.

  The present invention has been made in view of the above circumstances, and an object thereof is to realize a photosensor built-in type image display device capable of suppressing a decrease in detection sensitivity of a signal from a photosensor. Another object of the present invention is to realize an image display device in which a difference in luminance is unlikely to occur between pixels.

The present invention provides a transparent insulating substrate, a plurality of first wirings formed in parallel on the insulating substrate, and a plurality of second wirings intersecting the plurality of first wirings formed in parallel on the insulating substrate. A plurality of pixel units electrically connected to the first and second wirings and formed at each intersection of the plurality of first and second wirings on the insulating substrate; and An optical sensor circuit formed in at least one of the plurality of pixel units, and a third electrical circuit electrically connected to the optical sensor circuit and formed in parallel with the first wirings on the insulating substrate. The pixel unit is disposed between two first wirings located on both sides of the third wiring among the plurality of first wirings, and the third wiring, and the plurality of the first wirings . Among the pixel units, the optical sensor Since the area of the first pixel unit in which the circuit is formed is larger than the area of the second pixel unit in which the photosensor circuit is not formed, the aperture ratio of the first pixel unit, the aperture ratio of the second pixel unit, and Are substantially equal image display devices.

According to the present invention, the pixel units are respectively disposed between the two first wirings located on both sides of the third wiring among the plurality of first wirings and the third wiring. Therefore, the distance between the third wiring and the first wiring adjacent to the third wiring can be set at least by the width of the pixel unit, and the third wiring electrically connected to the photosensor circuit and the pixel unit electrically The capacitance value between the connected first wirings can be suppressed. Therefore, the effect of potential fluctuation on the first wiring is not easily transmitted to the third wiring via the capacitance, and an image display device with a built-in photosensor that can suppress a decrease in detection sensitivity of a signal from the photosensor is realized. can do. In addition, since the area of the first pixel unit in which the photosensor circuit is formed among the plurality of pixel units is larger than the area of the second pixel unit in which the photosensor circuit is not formed, the aperture ratio of the first pixel unit, The aperture ratio of the two pixel unit is substantially equal. Therefore, a difference in luminance between pixels is less likely to occur.

<Embodiment 1>
The present embodiment is an image display device in which a pixel unit is disposed between two data readout wirings located on both sides of a signal readout wiring and a signal readout wiring among a plurality of data wirings. By adopting such a configuration, it is possible to take a distance between the signal readout wiring and the data wiring on both sides by at least the width of the pixel unit, and the signal readout electrically connected to the optical sensor circuit. The capacitance value between the wiring for data and the data wiring electrically connected to the pixel unit can be suppressed.

  FIG. 1 is a circuit diagram of a part of the image display apparatus according to the present embodiment. 2 is a top view of the image display apparatus according to the present embodiment, and FIG. 3 is a cross-sectional view taken along the section line III-III in FIG. Note that the image display device according to the present embodiment is an active matrix liquid crystal display device in which a photosensor circuit as a touch sensor is built in a pixel unit.

  As shown in FIGS. 1 to 3, the image display device according to the present embodiment includes a transparent insulating substrate (for example, a glass substrate) 11, a plurality of data wirings 2 formed in parallel on the insulating substrate 11, A plurality of gate electrode wirings 1 that are formed in parallel on the insulating substrate 11 and intersect the data wiring 2, and are electrically connected to the data wiring 2 and the gate electrode wiring 1, and the data wiring 2 on the insulating substrate 11. And a plurality of pixel units Pr 1, Pg 1, Pb 1, Pr 2, Pg 2, Pb 2 formed at each intersection of the gate electrode wiring 1, and formed in parallel on the insulating substrate 11 and formed in parallel with the gate electrode wiring 1. A plurality of storage capacitor wires 3.

  Among these, the pixel units Pr1 and Pr2 are red pixel units, the pixel units Pg1 and Pg2 are green, and the pixel units Pb1 and Pb2 are blue pixel units. Further, the red, green, and blue pixel units Pr1, Pb1, and Pg1 are set as one dot (one picture element) in the color image. Each of the pixel units Pr1, Pg1, Pb1, Pr2, Pg2, and Pb2 includes a storage capacitor 4, a thin film transistor 5, and a pixel electrode 9. One of the source / drain of the thin film transistor 5 is connected to one electrode of the storage capacitor 4 and the pixel electrode 9, and the other of the source / drain of the thin film transistor 5 is connected to the data line 2. The gate of the thin film transistor 5 is connected to the gate electrode wiring 1, and the other electrode of the storage capacitor 4 is connected to the storage capacitor wiring 3.

  Note that a pixel unit in the present invention refers to a structural unit of a circuit necessary for constituting one pixel. Further, the red pixel unit Pr1, the green pixel unit Pg1, and the blue pixel unit Pb1 are arranged adjacent to each other in the extending direction of the gate electrode wiring 1, and they are combined to form a display area of the image display device. Constitutes one dot (picture element). The pixel units Pr2, Pg2, and Pb2 also constitute another dot, and the same applies to other pixel units that do not appear in the figure.

  In addition, the image display device according to the present embodiment includes a photosensor circuit formed in the pixel unit Pg1 on the insulating substrate 11 and the photosensor circuit, and the data wiring 2 on the insulating substrate 11. And an optical sensor signal readout wiring 10 formed in parallel with each other.

  The optical sensor circuit includes a thin film transistor 6 that functions as an optical sensor, an optical sensor storage capacitor 7, and a thin film transistor 8 for signal readout. One of the source / drain of the thin film transistor 8 is connected to one electrode of the photosensor storage capacitor 7 and one of the source / drain of the thin film transistor 6, and the other of the source / drain of the thin film transistor 8 is connected to the photosensor signal readout wiring 10. Connected. The gate of the thin film transistor 8 is connected to the gate electrode wiring 1, and the other of the gate and source / drain of the thin film transistor 6 and the other electrode of the photosensor storage capacitor 7 are connected to the storage capacitor wiring 3. For example, one photosensor circuit is provided for every two dots in a color image. In the above description, the optical sensor circuit is formed in the pixel unit Pg1, but it goes without saying that the optical sensor circuit may be formed in the pixel unit Pr1 instead of the pixel unit Pg1, or the pixel unit Pr1. An optical sensor circuit may be formed therein.

  As shown in FIG. 3, the storage capacitor wiring 3 is formed on the surface of the insulating substrate 11. Although not shown in FIG. 3, the gate electrode wiring 1 is also formed on the surface of the insulating substrate 11. A first interlayer insulating film 12 is formed so as to cover the surface of the insulating substrate 11 and the gate electrode wiring 1 and the storage capacitor wiring 3.

  On the surface of the first interlayer insulating film 12, the data wiring 2 and the optical sensor signal readout wiring 10 are formed. A second interlayer insulating film 13 is formed so as to cover the surface of the first interlayer insulating film 12 and the data wiring 2 and the optical sensor signal readout wiring 10. A pixel electrode 9 is formed on the second interlayer insulating film 13.

  The thin film transistor 6, the photosensor storage capacitor 7 and the thin film transistor 8 that constitute the photosensor circuit, and the storage capacitor 4, the thin film transistor 5, and the pixel electrode 9 that constitute the pixel unit are all in a common semiconductor manufacturing process (a photolithography process, , An etching process, a CVD (Chemical Vapor Deposition) process, etc.) are formed in the first interlayer insulating film 12 and the second interlayer insulating film 13 or on the surfaces thereof.

  In the present embodiment, a pixel is disposed between two data wirings 2 located on both sides of the optical sensor signal readout wiring 10 and the optical sensor signal readout wiring 10 among the plurality of data wirings 2. Units Pg1 and Pb1 are arranged. That is, in the present embodiment, the signal readout wiring 10 of the optical sensor circuit is arranged in the center of the pixel units Pg1 and Pb1, and the pixel electrodes 9 of the pixel units Pg1 and Pb1 are sandwiched between the signal readout wirings 10. Symmetrically, the data wiring 2 is arranged on both sides.

  Therefore, according to the image display apparatus according to the present embodiment, the distance between the optical sensor signal readout wiring 10 and the data wiring 2 adjacent to both of them can be taken by at least the width of the pixel units Pg1, Pb1. The capacitance value between the optical sensor signal readout wiring 10 electrically connected to the optical sensor circuit and the data wiring 2 electrically connected to the pixel units Pg1 and Pb1 can be suppressed. Therefore, the influence of the potential fluctuation on the data wiring 2 is not easily transmitted to the optical sensor signal readout wiring 10 via the capacitance, and the optical sensor built-in type that can suppress a decrease in detection sensitivity of the signal from the optical sensor. An image display device can be realized.

  In the present embodiment, an active matrix liquid crystal display device using the thin film transistor 5 has been described as an example. However, the application of the present invention is not necessarily limited to such a liquid crystal display device. . For example, the present invention may be applied to an active matrix type liquid crystal display device using a diode instead of a thin film transistor, and other passive matrix type liquid crystal display devices (in the case of an active matrix type liquid crystal display device using a diode). In addition, in the case of a passive matrix liquid crystal display device, a diode instead of a thin film transistor constitutes a pixel unit, and each electrode wiring at an intersection of a vertical electrode and a horizontal electrode constitutes a pixel unit.

  Further, the present invention is not limited to a liquid crystal display device, and is not limited to an image display device (for example, a plasma display panel or an organic EL panel) having a matrix-like signal wiring, an optical sensor circuit and a signal readout line similar to the above. The invention may be applied. Further, with respect to the optical sensor circuit, another light receiving element such as a photodiode may be employed instead of the thin film transistor 6.

<Embodiment 2>
The present embodiment is a modification of the image display device according to the first embodiment. In the image display device according to the first embodiment, the optical sensor circuit is provided in at least two adjacent pixel units. It is formed across.

  FIG. 4 is a circuit diagram of a part of the image display apparatus according to the present embodiment. FIG. 5 is a top view of the image display apparatus according to the present embodiment. 4 and 5, the thin film transistors 6 and 8 and the photosensor storage capacitor 7 constituting the photosensor circuit extend not only in the pixel unit Pg1 but also in the pixel unit Pb1 adjacent to the pixel unit Pg1. Is formed.

  That is, in the present embodiment, the thin film transistor 6 is formed in the pixel unit Pg1 as in the first embodiment, but the thin film transistor 8 and the photosensor storage capacitor 7 are adjacent to the pixel unit Pg1. It is formed in Pb1. Accordingly, as shown in FIG. 5, a wiring pattern for connecting one of the source / drain of the thin film transistor 6 to one electrode of the storage capacitor 7 for photosensor and one of the source / drain of the thin film transistor 8 is added. Yes.

  Since the device configuration is the same as that of the first embodiment except that the thin film transistor 8 and the photosensor storage capacitor 7 are formed in the pixel unit Pb1, description thereof will be omitted.

  According to the image display device according to the present embodiment, the photosensor circuit is formed across at least two adjacent pixel units (for example, pixel units Pg1 and Pb1). Therefore, the area of the photosensor circuit occupying one pixel unit can be reduced as compared with the case where the photosensor circuit is formed in one pixel unit. As a result, a decrease in the aperture ratio of the pixel unit in which the photosensor circuit is arranged can be suppressed, and an image display device that hardly causes a difference in luminance between pixels can be realized.

<Embodiment 3>
The present embodiment is a modification of the image display device according to the second embodiment. In the image display device according to the second embodiment, the area of the pixel unit in which the photosensor circuit is formed is determined by the photosensor circuit. By making it larger than the area of the pixel unit that is not formed, the aperture ratios of both pixel units are made substantially equal.

  FIG. 6 is a partial circuit diagram of the image display apparatus according to the present embodiment. FIG. 7 is a top view of the image display apparatus according to the present embodiment. 6 and 7, the dimensions Xg and Xb in the extending direction of the gate electrode wiring 1 of the pixel units Pg1 and Pb1 are the same as the extension of the gate electrode wiring 1 of the adjacent pixel unit Pr1 in the extending direction of the gate electrode wiring 1. It is larger than the dimension Xr in the current direction. Further, the dimension Y2 in the extending direction of the data wiring 2 of the pixel units Pg1 and Pb1 is larger than the dimension Y1 in the extending direction of the data wiring 2 of the adjacent pixel units Pg2 and Pb2 in the extending direction of the data wiring 2. Is also big.

  Thereby, the area of the pixel units Pg1, Pb1 in which the photosensor circuit is formed is larger than the area of the pixel units Pr1, Pg2, Pb2 in which the photosensor circuit is not formed. Thus, by making the area of the pixel units Pg1, Pb1 larger than the area of the pixel units Pr1, Pg2, Pb2 where the photosensor circuit is not formed, the aperture ratio of the pixel units Pg1, Pb1, and the pixel units Pr1, Pg2 , Pb2 are designed so that their aperture ratios are substantially equal.

  In the above description, it has been described that the dimensions Xg and Xb are larger than the dimension Xr and the dimension Y2 is larger than the dimension Y1, but the dimension Xg and Xb are equal to the dimension Xr and the dimension Y2 is larger than the dimension Y1. Alternatively, or by making the dimensions Xg and Xb larger than the dimension Xr while keeping the dimension Y2 equal to the dimension Y1, the area of the pixel units Pg1 and Pb1 is made larger than the area of the pixel units Pr1, Pg2 and Pb2. Also good.

  The dimension (Xr + Xg + Xb) in the extending direction of the one-dot gate electrode wiring 1 in the display area of the image display device, which is composed of the red pixel unit Pr1, the green pixel unit Pg1, and the blue pixel unit Pb1, is the total display area. The dimension in the extending direction of the gate electrode wiring 1 is divided by the number of dots in the entire display region in the extending direction of the gate electrode wiring 1. That is, the dimension (Xr + Xg + Xb) in the extending direction of the one-dot gate electrode wiring 1 is equal to the dot pitch in the extending direction of the gate electrode wiring 1.

  Further, the dimension Y2 in the extending direction of the data wiring 2 of the pixel units Pg1 and Pb1 is larger than the dimension Y1 in the extending direction of the data wiring 2 of the adjacent pixel units Pg2 and Pb2 in the extending direction of the data wiring 2. The sum (Y1 + Y2) of the dimensions in the extending direction of the data wiring 2 of the adjacent pixel units Pg1, Pb1, Pg2, Pb2 is the dimension in the extending direction of the data wiring 2 in the entire display area. This is twice the value divided by the number of dots in the entire display area in the extending direction of the data wiring 2. That is, 1/2 (average value) of the sum (Y1 + Y2) of dimensions in the extending direction of the data wiring 2 of the pixel units Pg1, Pb1, Pg2, and Pb2 is equal to the dot pitch in the extending direction of the data wiring 2. .

  Since the apparatus configuration is the same as that of the second embodiment except that the planar shape of the pixel units Pr1, Pg1, Pb1, Pr2, Pg2, and Pb2 is changed for aperture ratio adjustment, the description is omitted. .

  According to the image display apparatus according to the present embodiment, the area of the pixel units Pg1, Pb1 in which the photosensor circuit is formed among the plurality of pixel units is the area of the pixel units Pr1, Pg2, Pb2 in which the photosensor circuit is not formed. By being larger, the aperture ratios of the pixel units Pg1, Pb1 and the aperture ratios of the pixel units Pr1, Pg2, Pb2 are substantially equal. Therefore, a difference in luminance between pixels is less likely to occur.

  Further, the dimensions Xg, Xb in the extending direction of the gate electrode wiring 1 of the pixel units Pg1, Pb1 are larger than the dimensions Xr in the extending direction of the gate electrode wiring 1 of the adjacent pixel unit Pr1 in the extending direction of the gate electrode wiring 1. Is also big. Therefore, the area of the pixel units Pg1 and Pb1 can be made larger than the area of the pixel unit Pr1. In addition, at least one of the red pixel unit Pr1, the green pixel unit Pg1, and the blue pixel unit Pb1 in one dot is a pixel unit in which a photosensor circuit is formed, and at least one other is a photosensor circuit. This is a pixel unit that is not formed. Therefore, without changing the dimension (Xr + Xg + Xb) in the extending direction of the one-dot gate electrode wiring 1, the pixel unit in which the photosensor circuit in one dot is formed and the gate electrode wiring of the pixel unit in which the photosensor circuit is not formed By adjusting the dimensions Xr, Xg, and Xb in the extending direction of 1, the aperture ratio of the pixel unit in which the photosensor circuit is formed and the pixel unit in which the photosensor circuit is not formed can be adjusted.

  Further, the dimension Y2 in the extending direction of the data wiring 2 of the pixel units Pg1 and Pb1 is larger than the dimension Y1 in the extending direction of the data wiring 2 of the adjacent pixel units Pg2 and Pb2 in the extending direction of the data wiring 2. Is also big. Therefore, the area of the pixel units Pg1, Pb1 can be made larger than the area of the pixel units Pg2, Pb2. The sum (Y1 + Y2) of the dimensions in the extending direction of the data wiring 2 of the adjacent pixel units Pg1, Pb1, Pg2, and Pb2 is the dimension in the extending direction of the data wiring 2 in the display area of the image display device. This is twice the value divided by the number of dots in the display area in the extending direction of the data wiring 2. Therefore, the dimensions Y1 and Y2 in the extending direction of the data wiring 2 of the adjacent pixel units Pg1, Pb1, Pg2, and Pb2 are changed without changing the dimensions of the adjacent two dots in the extending direction of the data wiring 2. By adjusting, the aperture ratio of the pixel unit in which the photosensor circuit is formed and the pixel unit in which the photosensor circuit is not formed can be adjusted.

1 is a circuit diagram of an image display device according to Embodiment 1. FIG. 1 is a top view of an image display device according to Embodiment 1. FIG. 1 is a cross-sectional view of an image display device according to Embodiment 1. FIG. 6 is a circuit diagram of an image display device according to Embodiment 2. FIG. 6 is a top view of an image display apparatus according to Embodiment 2. FIG. 6 is a circuit diagram of an image display device according to Embodiment 3. FIG. 6 is a top view of an image display device according to Embodiment 3. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Gate electrode line, 2 data wiring, 3 storage capacity wiring, 4 storage capacity, 5 thin film transistor, 6 thin film phototransistor, 7 optical sensor storage capacity, 8 thin film transistor, 9 pixel electrode, 10 optical sensor signal readout wiring, 11 Insulating substrate, Pr1, Pg1, Pb1, Pr2, Pg2, Pb2 pixel unit.

Claims (4)

A transparent insulating substrate;
A plurality of first wirings formed in parallel on the insulating substrate;
A plurality of second wirings intersecting with the plurality of first wirings formed in parallel on the insulating substrate;
A plurality of pixel units electrically connected to the first and second wirings and formed on each of the intersections of the plurality of first and second wirings on the insulating substrate;
An optical sensor circuit formed in at least one of the plurality of pixel units on the insulating substrate;
A third wiring electrically connected to the photosensor circuit and formed in parallel with the plurality of first wirings on the insulating substrate;
The pixel units are respectively disposed between two first wirings located on both sides of the third wiring among the plurality of first wirings, and the third wiring .
Of the plurality of pixel units, the area of the first pixel unit in which the photosensor circuit is formed is larger than the area of the second pixel unit in which the photosensor circuit is not formed. An image display device in which the aperture ratio of the second pixel unit is substantially equal . The image display device according to claim 1,
The optical sensor circuit is an image display device formed over at least two adjacent pixel units. The image display device according to claim 1,
A dimension of the first pixel unit in the extending direction of the second wiring is larger than a dimension of the second pixel unit adjacent in the extending direction of the second wiring in the extending direction of the second wiring;
The plurality of pixel units include red, green, and blue pixel units arranged adjacent to each other in the extending direction of the second wiring,
The red pixel unit, the green pixel unit, and the blue pixel unit form a set to constitute one dot in the display area of the image display device,
Among the red pixel unit, the green pixel unit, and the blue pixel unit in the one dot, at least one is the first pixel unit, and at least one other is the second pixel unit,
The dimension in the extending direction of the second wiring of the one dot is obtained by dividing the dimension in the extending direction of the second wiring in the display area by the number of dots in the display area in the extending direction of the second wiring. Value is an image display device. The image display device according to claim 1 ,
A dimension of the first pixel unit in the extending direction of the first wiring is larger than a dimension of the second pixel unit adjacent in the extending direction of the first wiring in the extending direction of the first wiring;
The sum of the dimensions in the extending direction of the first wiring of the adjacent first and second pixel units is the dimension in the extending direction of the first wiring in the display area of the image display device. An image display device that is twice the value divided by the number of dots in the display area in the extending direction of the display area .

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