JP2007011152A - Flat display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat display device which has no variance in characteristic and can precisely input an image thereinto. <P>SOLUTION: A photosensor processing circuit (1) applies a precharge voltage to a photosensor pixel 27 from a precharge voltage supply line and also reads the potential of a photosensor signal output line varying depending upon the on/off state of a second TFT 64b as a photosensor signal when a third TFT 64c is on, and (2) counts photosensors 64 which are on or off by processing blocks and judges whether a photosensor 64 of a processing block 881 is on or off from the counted value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flat display device having an image capturing function.

  Recently, a display device has been proposed in which a contact area sensor for capturing an image is arranged on an array substrate of a liquid crystal display device (see, for example, Patent Documents 1 and 2).

This conventional liquid crystal display device captures an image by changing the charge amount of a capacitor connected to the sensor in accordance with the amount of light received by the sensor and detecting the voltage across the capacitor.
JP 2001-292276 A JP 2001-339640 A

  However, the transistors and the like that constitute the contact area sensor have large characteristic variations. Therefore, some transistors are turned off even when the same external light is irradiated to the sensor or the like, and some transistors are kept off.

  Therefore, the present invention has been made in view of such a point, and provides a flat display device capable of accurately capturing an image without variation in characteristics.

  The present invention relates to a plurality of signal lines and first gate signal lines arranged orthogonally to each other on an array substrate, and a display switching element provided in the vicinity of the intersection of the signal line and the first gate signal line A display pixel including a pixel electrode connected to the display switching element, and a display control for supplying a video signal to the signal line and supplying a gate signal to the first gate signal line to display an image. A plurality of photosensor pixels are provided in a matrix on the array substrate, and a photosensor processing means for reading a photosensor signal from each photosensor pixel is provided. A first switching element that is turned on / off by a second gate signal from a second gate signal line disposed in parallel with the first gate signal line; When the switching element is in an ON state, a capacitor for storing a charge by applying a predetermined precharge voltage from a precharge voltage supply line arranged in parallel with the signal line, and a charge stored by the capacitor for light A photosensor that discharges by changing the amount of light leakage according to the intensity of the light, a second switching element that is turned on / off based on a discharge voltage from the capacitor, and a third sensor that is arranged in parallel with the first gate signal line. A plurality of photosensor pixels arranged in a matrix having a third switching element for turning on / off between the second switching element and the photosensor signal output line by a third gate signal from the gate signal line And a plurality of the blocks are provided on the array substrate, and the photosensor processing means includes: (1) front When the precharge voltage is applied from the precharge voltage supply line and the third switching element is in the on state, the potential of the photosensor signal output line that changes depending on the on / off state of the second switching element is a photosensor signal. (2) The number of the photosensors in the on state or the off state is counted for each processing block, and whether the photosensors in the processing block are in the on state or the off state according to the counted number. It is a flat display device characterized by judging.

  According to the present invention, the number of photo sensors in the on state or the off state is counted for each processing block, and it is determined whether the photo sensor in the processing block is in the on state or the off state based on the counted number. Can be eliminated.

  Hereinafter, a liquid crystal display device according to an embodiment of the present invention will be described.

[1] Circuit Configuration of Liquid Crystal Display Device First, details of the circuit configuration of the liquid crystal display device will be described.

(1) Configuration of Liquid Crystal Display Device The configuration of the liquid crystal display device of this embodiment will be described with reference to FIG.

  FIG. 1 shows the array substrate 11 and the circuit board 17.

  The liquid crystal display device has a display resolution of 320 pixels in the horizontal direction and 240 pixels in the vertical direction. The pixel 16 is a name used when the display pixel 26 and the photosensor pixel 27 are expressed together.

  On the array substrate, 320 × R, G, B = 960 source signal lines 21 are wired in the vertical direction, and 340 display gate signal lines 22a are wired. A pixel 16 is provided in the vicinity of the intersection of the source signal line 21 and the display gate signal line 22a.

  Also, 960 precharge voltage signal lines 24, 340 second gate signal lines 22c, 340 third gate signal lines 22b, 340 common signal lines 31, 960 photosensor output signal lines 25 are provided. is doing. The precharge voltage signal line 24 and the photosensor output signal line 25 are wired in parallel with the signal line 23, and the second gate signal line 22c, the third gate signal line 22b, and the common signal line 31 are connected to the display gate signal line 22a. Wired in parallel.

  On the array substrate 11, the source driver circuit 14 to which the source signal line 23 is connected, the photo sensor processing circuit 18 to which the precharge voltage signal line 24 is connected, and the display gate signal line 22a are driven. The display gate driver circuit 12, the read gate driver circuit 12b to which the third gate signal line 22b, the second gate signal line 22c, and the common signal line 31 are connected, and the photosensor to which the photosensor output signal line 25 is connected. An output processing circuit 18 is provided. These circuits are formed by, for example, a low-temperature polysilicon TFT.

(2) Configuration of Each Circuit On the circuit board 17, a control IC (not shown) for controlling each circuit on the array board 11, a memory (not shown) for storing image data, and the like, A power supply circuit (not shown) for outputting various DC voltages used on the circuit board 17 is mounted. A video signal processing circuit 21 that performs display control and image capture control is mounted on the circuit board 17. The array substrate 11 and the circuit substrate 17 transmit and receive various signals via, for example, a flexible substrate (FPC) 20. The output video signal from the video signal processing circuit 21 is applied to the source driver circuit 14.

  The source driver circuit 14 includes a D / A conversion circuit that converts digital pixel data input from the video signal processing circuit 21 into an analog voltage suitable for driving a liquid crystal display element.

  The display gate driver circuit 12 a sequentially selects the display gate signal lines 22 a and performs an operation of writing video data to the display pixels 26 in synchronization with the source driver circuit 14.

  The reading gate driver circuit 12b sequentially selects the third gate signal line 22b and the second gate signal line 22c, applies a precharge voltage to the photosensor pixel 27 in synchronization with the source driver circuit 14, and also detects the photosensor pixel. The operation of taking out the output voltage from 27 is performed.

  The photosensor processing circuit 18 applies a precharge voltage to the precharge voltage signal line 24. The photo sensor processing circuit 18 takes in the output voltage from the photo sensor pixel 27 via the photo sensor output signal line 25. The photo sensor processing circuit 18 is directly formed on the array substrate 11. A basic component is a selection circuit including a switch for the comparator circuit 233.

  The photosensor signal processing circuit 15 controls the reading gate driver circuit 12b and the photosensor processing circuit 18. Further, the output data from the photosensor processing circuit 18 is subjected to calculation or comparison processing, etc., the photosensor position where light is irradiated or shielded is determined, and the coordinate position is output.

(3) Configuration of Pixel 16 FIG. 2 is a block diagram of the liquid crystal display device of the present embodiment, which is shown in detail centering on the pixel 16 (display pixel 26 + photosensor pixel 27). Although only one pixel 16 is shown, the pixels are formed in a matrix as shown in FIG.

(3-1) Configuration of Display Pixel 26 The display pixel 26 is formed in the vicinity of each intersection of the source signal line 23 and the display gate signal line 22a arranged in rows and columns. The display pixel 26 includes a low-temperature polysilicon thin film transistor (hereinafter referred to as a display TFT) 32 (see FIG. 3), a liquid crystal capacitor 34 formed between a pixel electrode 61 formed at one end of the display TFT 32 and a counter electrode 36, The auxiliary storage capacitor 35 is connected to the common signal line 31.

(3-2) Configuration of Photosensor Pixel 27 As shown in FIG. 6, the photosensor pixel 27 includes a photosensor 64 made of TFT, a capacitor 63 that holds a precharge voltage, a second TFT 62b that operates as a source follower, and a precharge. The first TFT 62a operates as a switching element that applies a voltage to the capacitor 63, and a third TFT 62c that selects and outputs the source follower output of the second TFT 62b to the photosensor output signal line 25. One terminal such as the photosensor 64 is connected to the common signal line 31 and grounded. The first TFT 62a, the second TFT 62b, the third TFT 62c, and the photosensor 64 are formed together with the display TFT 32 in the same array process.

(2-3) Arrangement of Photosensor Pixel 27 In FIG. 3, the photosensor pixel 27 is formed in each of the pixels 16. That is, the number of display pixels 26 and the number of photosensor pixels 27 are the same.

  However, as shown in FIG. 4, the photosensor pixel 27 may include one photosensor pixel 27 for each of the RGB pixels 16 (16R, 16G, and 16B).

  Further, as shown in FIG. 5, one photosensor pixel 27 may be arranged or formed for every two pixels. Preferably, as shown in FIG. 5, the photo sensor pixel 27 is arranged in the odd pixel column of the even pixel row, and the photo sensor pixel 27 is arranged in the even pixel column of the odd pixel row.

  As described above, the photosensor pixels 27 are not limited to be formed corresponding to all the display pixels 26.

  The position of the photosensor pixel 27 is not limited to the display area 10 and may be configured outside the display area.

  Further, the number of photosensor pixels 27 formed in the pixel 16 is not limited to one, and a plurality of photosensor pixels 27 may be formed.

(4) Configuration of Equivalent Circuit of Photosensor Pixel 27 An equivalent circuit of the photosensor pixel 27 will be described with reference to FIGS.

  The equivalent circuit of the photosensor pixel 27 includes a photosensor 64, a capacitor 63, a first TFT 62a, a second TFT 62b, and a third TFT 62c.

  The photosensor 64 is composed of a TFT that operates as a photodiode. In this embodiment, the photosensor 64 is formed by N-channel diode connection of TFT. By connecting the TFT with an N-channel diode, the configuration becomes easy and the charge retention characteristics are improved. When the photosensor 64 is irradiated with light, the photosensor 64 leaks according to the intensity of the light. Due to this leakage, the potential between both terminals of the photosensor 64 decreases. Therefore, by detecting the potential between both terminals of the photosensor 64, it is possible to grasp that the photosensor 64 is irradiated with light and the relative intensity of the light irradiated to the photosensor 64.

  The capacitor 63 holds a precharge voltage and is configured using a gate insulating film. By using the gate insulating film, an auxiliary capacitor having a small area and a large capacitance can be configured.

  The second TFT 62b operates as a source follower, and one terminal of the photosensor 64 is connected to the gate terminal, and one terminal of the capacitor 63 is connected. When the gate terminal voltage of the second TFT 62b becomes the Vt voltage, the second TFT 62b is turned off. If it is equal to or higher than the Vt voltage, the second TFT 62b is turned on.

  The first TFT 62 a applies the precharge voltage applied to the precharge voltage signal line 24 to one terminal of the capacitor 63. When a turn-on voltage is applied to the second gate signal line 22c, the first TFT 62a is turned on. The precharge voltage is a voltage at which the second TFT 62b is turned on (Vt voltage or more). The first TFT 62a is controlled by the gate driver circuit 12b, and the gate terminal of the first TFT 62a is connected to the second gate signal line 22c.

  The third TFT 62c is controlled by the gate driver circuit 12b, and the gate terminal of the third TFT 62c is connected to the third gate signal line 22b. When a turn-on voltage is applied to the third gate signal line 22b, the third TFT 62c is turned on.

(5) Operation Contents of Equivalent Circuit of Photosensor Pixel 27 Hereinafter, operation contents of an equivalent circuit of the photosensor pixel 27 having the above-described configuration will be described.

(5-1) First Operation When a turn-on voltage is applied to the second gate signal line 22c, the first TFT 62a is turned on. Then, the precharge voltage applied to the precharge voltage signal line 24 is applied to one terminal of the capacitor 63. The precharge voltage is applied every frame (one screen rewrite cycle). Of course, it may be applied once to a plurality of frames.

(5-2) Second Operation The capacitor 63 stores a precharge voltage.

(5-3) Third Operation When the photosensor 64 is irradiated with light, the electric charge accumulated in the capacitor 63 is discharged between the channels of the photosensor 64. The second TFT 62b is turned on or off depending on the discharged discharge voltage value. The discharge voltage value of the photosensor 64 is determined by the amount of light leak corresponding to the light intensity.

(5-4) Fourth Operation When a turn-on voltage is applied to the third gate signal line 22b, the third TFT 62c is turned on. The timing for turning on the third TFT 62c is performed in synchronization with the timing for applying the precharge voltage.

  At this time, if the second TFT 62b is in an ON state, the charge of the photosensor output signal line 25 is discharged to the common signal line 31 via the third TFTs 62c and 62b. For example, the common signal line 31 is grounded although it may be charged depending on the potential of the common signal line 31.

  On the other hand, even if the third TFT 62c is turned on, the charge of the photosensor output signal line 25 does not change if the second TFT 62b is turned off.

(5-5) Definition of Exposure Time in Equivalent Circuit Here, “exposure time” used below is defined. The exposure time is the time from when the first TFT 62a is turned on and the precharge voltage is applied to the gate terminal of the second TFT 62b to when the third TFT 62c is turned on and the output is taken out to the photosensor output signal line 25.

(5-6) Summary of Equivalent Circuit As described above, if a change in the charge of the photosensor output signal line 25 is detected, it is detected whether the second TFT 62b is in an on state, an intermediate on state, or an off state. Can do. That is, this detection detects the potential of the gate terminal of the second TFT 62b. The gate terminal voltage of the second TFT 62b varies depending on the magnitude of the precharge voltage, the intensity of light applied to the photosensor 64, and the exposure time. That is, it is possible to detect the intensity of light applied to the photosensor 64 from the magnitude of the precharge voltage, the length of the exposure time, and the amount of light leakage of the photosensor 64.

  The light intensity detection corresponds to an operation for reading an image like an image scanner. In the present embodiment, the photosensor pixels 27 are formed in a matrix. Therefore, by detecting the on / off state of the second TFT 62b of each photosensor pixel 27, an image image formed or illuminated on the display region 10 can be captured. In addition, the shadow of the object and the light reflected by the object can be detected.

(6) Configuration of Photosensor Processing Circuit 18 FIG. 8 is a configuration diagram illustrating the peripheral portion of the pixel 16.

  The photosensor output signal line 25 is connected to the photosensor processing circuit 18. The photo sensor processing circuit 18 mainly includes a comparator circuit 233 and a selection circuit 81. The selection circuit 31 is an analog switch as an example. The selection circuit 81 includes a shift register circuit in addition to the switching or selection circuit.

  The connection state between the photosensor pixel 27 and the comparator circuit 233 is shown in FIG. The comparator circuit 233 may be an operational amplifier circuit or a differential amplifier. In other words, any one may be used as long as the output of the circuit 233 changes with respect to the comparison voltage or the comparison reference at one terminal.

  The comparator circuit 233 determines whether it is larger or smaller than the comparison voltage Vref, and outputs (binarizes) H or L logically. Therefore, since the output is converted into a logic signal, the subsequent logic processing becomes easy.

(7) Function of Comparator Circuit 233 Next, the comparator circuit 233 will be described with reference to FIG.

  As shown in FIG. 8, a precharge voltage Vpr is applied to the precharge voltage signal line 24 from a precharge voltage terminal 83. The precharge voltage is applied in synchronization with the video signal output from the source driver circuit 14. As the precharge voltage, the same precharge voltage is applied to all the precharge voltage signal lines 24.

  The comparison voltage Vref is applied from the comparator voltage terminal 83 to one terminal of the input terminals of all the comparator circuits 233. The comparison voltage Vref applies the same voltage to all the comparator circuits 233.

  One end of the photosensor output signal line 25 is connected to the input terminal of the comparator circuit 233. A selection circuit 81 is connected to the output terminal of the comparator circuit 233. A switch Sk (k = 1 to n, where n is the number of pixel columns) of the selection circuit 81 is formed, and one switch Sk is selected. The output of the selected comparator circuit 233 is connected to the voltage output terminal. Therefore, an output voltage is output to the output voltage terminal 82. The switch Sk (k = 1 to n) is configured to be selected at least once in one horizontal scanning period. That is, the gate driver circuit 12b selects the third gate signal line 22b in synchronization with one horizontal scanning period (hereinafter referred to as “1H”) clock, and outputs the output voltage of the third TFT 62c to the photosensor output signal line 25 (FIG. 10).

(8) Display Method and Reading Method The display method and reading method will be described with reference to FIG.

  The video signal is applied to the source signal line 23 in units of 1H corresponding to the display image. The polarity of the video signal is inverted every 1H. The polarity applied to each pixel row is inverted every frame.

  The display gate signal line 22 a sequentially selects pixel rows in synchronization with the 1H clock, and the TFT 32 of the selected pixel 16 writes the video signal applied to the source signal line 23 to the pixel electrode 61.

  The read gate driver circuit 12b selects the gate signal line 22a in the 1H cycle and shifts the position of the second gate signal line 22c to be sequentially selected. The shifting method is matched with the shift direction of the gate signal line 22a. When an on voltage is applied to the second gate signal line 22c, the first TFT 62a corresponding to the pixel row connected to the second gate signal line 22c is turned on. Therefore, it is applied to the precharge voltage signal line 83. A precharge voltage is applied to the photosensor 64. The precharge voltage may be changed every 1H, but is preferably a constant voltage.

  When the photosensor 64 is irradiated with light, the electric charge is discharged through the photosensor 64, and the terminal voltage of the photosensor 64 is lowered from the precharge voltage. The decrease is determined by the intensity and time of the light applied to the photosensor 64. If the applied precharge voltage drops below the Vt voltage of the second TFT 62b, the second TFT 62b is turned off, and if it is above the Vt voltage, the second TFT 62b is turned on.

  Similarly, the gate driver circuit 12b sequentially selects the third gate signal line 22b in synchronization with the 1H clock, and sequentially selects pixel rows. The switching third TFT 62c of the selected photosensor pixel 27 outputs the output of the second TFT 62b to the voltage output signal line. To 25. When the photosensor 64 is irradiated with light, the electric charge is discharged through the photosensor 64, and the terminal voltage of the photosensor 64 is lowered from the precharge voltage. As described above, the voltage drop (discharge of electric charge) is determined by the intensity and time of light applied to the photosensor 64. Further, it is determined by the capacity of the capacitor 63. Of course, it is also determined by the magnitude of the precharge voltage. When the applied precharge voltage decreases and is equal to or lower than the Vt voltage of the second TFT 62b, the second TFT 62b is turned off, and when it is equal to or higher than the Vt voltage, the second TFT 62b is turned on. Therefore, the operating state of the second TFT 62b can be output to the voltage output signal line 25 by turning on the third TFT 62c.

(9) Exposure time Next, the exposure time will be described. The exposure time has been described above, but will be described in more detail.

  As shown in FIG. 10, after selecting the second gate signal line 22c, the third gate signal line 22b is selected after the A period has elapsed. This period A is called “exposure time”. That is, the exposure time is the time from when the precharge voltage is applied to an arbitrary photosensor pixel 27 until reading. To be precise, this is the time from when the precharge voltage applied to the photosensor 64 is determined until the voltage is output to the photosensor output signal line 82 and the output state becomes stable and can be called from the voltage output terminal 82. However, generally, the time from the timing at which the precharge voltage is applied to the photosensor pixel 27 to the timing at which the holding voltage of the photosensor 64 of the applied photosensor pixel 27 is read is defined as the exposure time. Since the selection timing of the third gate signal line 22b and the second gate signal line 22c is synchronized, the time for detecting the terminal voltage of the photosensor 64 is relatively proportional even if the exposure time is adjusted. Therefore, the external light intensity can be grasped with high accuracy. Further, there is no problem even if the photosensor 64 differs depending on the lot of the array substrate 11.

  The exposure time can be adjusted as shown in FIG.

  FIG. 12A shows a selection signal for the second gate signal line 22c. An on-voltage is applied to the second gate signal line 22c for a fixed period of 1H, and a precharge voltage is applied to the photosensor pixel 27. FIG. 12B shows a selection signal for the third gate signal line 22b. An ON voltage is applied to the third gate signal line 22b for a certain period of 1H, and a voltage or the like is extracted from the photosensor pixel 27 to the photosensor output signal line 25. FIG. 12B1 shows a case where the exposure time is within 1H. FIG. 12B2 shows an embodiment when the exposure time is 1H or more (near 2H in the figure). FIG. 12B3 shows an embodiment when the exposure time is nH (n is an integer).

  Although FIG. 12 shows a unit of 1H, a unit of 1H or less may be used. Further, the exposure time may be adjusted in units of one frame. The precharge voltage and the exposure time are adjusted so as to be optimally output from the voltage output terminal 82.

  It is preferable to add an enable (OEV) circuit to the gate driver circuit 12b as shown in FIG. 13 which realizes the exposure time setting within 1H. Only when the H logic voltage is applied to the enable terminal (OEV) terminal and the period during which the gate driver circuit 12b outputs the H logic voltage for selecting the third gate signal line 22b is ANDed. A turn-on voltage is applied to the three gate signal line 22b.

  In the configuration of the gate driver circuit 12b shown in FIG. 8 and the like, there is no enable terminal (OEV) terminal. Therefore, the ON voltage (selection voltage) is applied to the second gate signal line 22c during the period in which the gate driver circuit 12b outputs the H logic voltage for selecting the third gate signal line 22b.

  However, in the configuration of FIG. 13, the period during which the ON voltage is applied to the third gate signal line 22b can be reduced to 1H or less by controlling the logic voltage of the enable terminal (OEV).

  Therefore, when the gate driver circuit 22b selects the third gate signal lines 22b and 22c formed in the same photosensor pixel 27 in the 1H period and applies the precharge voltage, the third gate signal line 22b is connected to the OEV terminal. Unselected by control. That is, the third gate signal line 22b is selected by the shift register circuit, but the off voltage is applied to the third gate signal line 22b by the OEV terminal. After the precharge voltage is applied to the photosensor 64, after the exposure time within 1H has elapsed, the selected state is established by controlling the OEV terminal connected to the third gate signal line 22b. That is, the ON voltage is applied to the third gate signal line 22b by the OEV terminal. Accordingly, the third TFT 62c is turned on, and the output of the second TFT 62b is output to the photosensor output signal line 25.

  The configuration or operation related to the OEV described above can be applied to the gate driver circuit 12. It is also preferable to apply to the gate signal line 22a and the second gate signal line 22c.

(10) Terminal voltage of the photosensor 64 The terminal voltage of the photosensor 64 varies depending on the magnitude of the precharge voltage applied to the photosensor 64, the intensity of external light applied to the photosensor 64, and the like. This change is shown in FIG. A precharge voltage is applied during period A in FIG.

  FIG. 11A shows the case where the precharge voltage Vprc = 3.5V. After the precharge voltage Vprc of 3.5 V is applied, when the external light applied to the photosensor 64 is weak, the terminal voltage of the photosensor 64 changes along the straight line a. When the external light irradiated to the photosensor 64 is strong, the terminal voltage of the photosensor 64 changes along the straight line b. After the period B, the third TFT 62c is turned on, and a voltage or the like is taken out to the photosensor output signal line 25. In the case of the b straight line in FIG. 11 (1), 1.0 V is taken out to the photosensor output signal line 25. If the B period is short, the voltage of the photosensor output signal line 25 becomes 1.0 V or more. If the period B is long, the voltage of the photosensor output signal line 25 is 1.0 V or less.

  FIG. 11B shows the case where the precharge voltage Vprc = 4.0V. After the precharge voltage Vprc of 4.0 V is applied, when the external light applied to the photosensor 64 is weak, the terminal voltage of the photosensor 64 changes along the straight line a. When the external light irradiated to the photosensor 64 is strong, the terminal voltage of the photosensor 64 changes along the straight line b. After the period B, the switching third TFT 62c is turned on, and a voltage or the like is taken out to the photosensor output signal line 25. If the change in impedance of the photosensor 64 with respect to the light irradiation intensity is proportional, the slope of the b line in FIG. 11 (1) and the slope of the b line in FIG. 11 (2) are the same. The inclination of the a line in FIG. 11 (1) is the same as the inclination of the a line in FIG. 11 (2). However, 1.0 V is taken out to the photosensor output signal line 25.

  FIG. 11 (3) shows the case where the precharge voltage Vprc = 4.5V, and FIG. 11 (4) shows the case where the precharge voltage Vprc = 5.0V.

(11) Relationship between exposure time and precharge voltage The sensitivity to external light is adjusted by changing the precharge voltage. Also, the sensitivity is adjusted by changing the precharge voltage with respect to the exposure time.

  FIG. 9 is an explanatory diagram of this. The leak amount of the photosensor 64 increases as the outside light increases. Further, the electric charge is discharged substantially in proportion to the exposure time. In order to adjust the precharge voltage so that it is changed to Vt of the second TFT 62b, the exposure time is shortened when the external light to the photosensor 64 is strong. When the external light to the photosensor 64 is weak, the exposure time is lengthened. The above relationship is illustrated in FIG. Therefore, when the external light is very strong, the exposure time is extremely shortened. In addition, when the sensitivity of the photosensor 64 is very good with respect to outside light, the exposure time is extremely shortened.

  Even if the exposure time is shortened, if the gate terminal voltage of the second TFT 62b immediately reaches the Vt voltage or less, and the change signal to the photosensor output signal line 25 cannot be determined, the precharge voltage Vprc is increased by the electronic volume 261a. Set. That is, when the output of the second TFT 62b of the full screen is output in the off state, that is, in the state where the output from the display panel of the present embodiment cannot obtain the same imaging data, the precharge voltage Vprc is set by the electronic volume 261a. Set high. By setting the precharge voltage Vprc high, it takes a long time to reach the Vt voltage of the second TFT 62b, so that imaging data (captured image data, shadow of an object, etc.) can be obtained.

  If the gate terminal voltage of the second TFT 62b is quite far below the Vt voltage even if the exposure time is extended, and the change signal to the photosensor output signal line 25 cannot be determined, the precharge voltage Vprc is set lower by the electronic volume 261a. That is, when the output of the second TFT 62b of the full screen is output in the ON state, that is, in the state where the output from the display panel of the present embodiment cannot obtain the same imaging data, the precharge voltage Vprc is set by the electronic volume 261a. Set low. By setting the precharge voltage Vprc voltage low, the time to reach the Vt voltage of the second TFT 62b is shortened, so that imaging data (captured image data, object shadow, etc.) can be obtained.

  A better result is obtained when the exposure time is within one frame. This is presumably because it is not easily affected by the coupling from the source signal line 23 to which the video signal is applied. This is because the polarity of the video data is inverted every frame, and the potential of the photosensor 64 fluctuates due to the influence of this inversion.

  As described above, the present embodiment is characterized in that imaging data is obtained by adjusting the exposure time and the precharge voltage. Also, the comparator voltage Vref is basically set to a fixed value.

(12) Matrix Processing The photosensor 64 is formed in the same process as the pixel 26. The process used is polysilicon technology. The semiconductor film by polysilicon technology is formed by laser annealing technology. Therefore, the characteristics vary greatly depending on the temperature distribution of the laser beam. In response to this problem, the present embodiment performs matrix processing as shown in FIG.

  Details will be described in [4] Characteristic variation correction, but an outline will be described here.

Matrix processing is a combination of a plurality of photosensor pixels 27 arranged in a matrix to form one block, counts the output of the photosensor pixels 27 in this one block, and performs signal processing based on the count value.
In the laser annealing method, the characteristics of the second TFT 62b and the photosensor 64 are characteristic distributions having an inclination from one direction of the display area to the other direction. In order to correct this characteristic distribution, the area where the photosensor 64 is formed is irradiated with uniform external light, the exposure time is constant, the precharge voltage is constant, and the output of the second TFT 62b for each block. Are counted and added. The output from the voltage output terminal 82 is converted into binary data (on (1), off (0)) by the comparator circuit 233.

  For example, in a 10 × 10 block, the count value ranges from 0 to 100. This count value is totaled and stored for each photosensor 64 in the block. That is, the calibrated count value is stored in memory.

  Data picked up by the liquid crystal display device is also processed in the same block section, and the previously calibrated count value is subjected to difference processing at a constant ratio from the processed count value. Since the characteristic distribution of the photo sensor 64 and the like is subtracted from the performed data, good imaging data is obtained.

  As described above, the influence of the distribution of the photosensor 64 and the second TFT 62b is removed or reduced in the data resulting from the difference processing. In addition, the variation due to the characteristic distribution of the small area is not affected by the characteristic distribution of the small area because the block processing is performed and the output data of the block is handled as one data (which is consequently averaged). . For example, if the second TFT 62b of another photosensor pixel 27 is good even if the second TFT 62b having a low laser shot and a high Vt voltage is distributed in the block, if the second TFT 62b having a high Vt voltage is good, There is no effect.

  The concept of the block is not limited to this. For example, as shown in FIG. In FIG. 14B, it is divided into blocks in units of 3 pixel columns. It may be divided into blocks in the horizontal direction (pixel row direction).

[2] Structure of Liquid Crystal Display Device Hereinafter, the structure of the liquid crystal display device and the reading method will be described with reference to FIGS.

(1) Structure of liquid crystal display device The array substrate 11 is made of a glass substrate or an organic material.

  A color filter is formed on the display pixel 26. A black matrix (hereinafter referred to as BM) is formed between the color filters.

  One or a plurality of phase films are arranged between the array substrate 11 and the polarizing plate 145.

  Pixels 16 (display pixels 26 + photosensor pixels 27) are arranged in a matrix on the array substrate 11. The array substrate 11 and the counter substrate 144 sandwich the sealing wall 142. A counter electrode 147 (36) is formed on the counter substrate 144. A polarizing plate 145 a is disposed on the array substrate 11, and a polarizing plate 145 b is disposed on the opposing substrate 144. Light 151 emitted from the backlight 146 enters from the counter substrate 144 side, is modulated by the liquid crystal layer 143, and is transmitted through the display pixels 26 from the array substrate 11 side.

(2) First Reading Operation of Object 141 As shown in FIG. 22, it is assumed that an object 141 that is a finger or an image scanner object (image paper) is arranged on the array substrate 11 side.

  Light 151a emitted from a place where the object 141 is not present is transmitted as it is. When there is an object 141, it is reflected by the object. The reflected light 151b is incident on the photosensor pixel 27 at the B position. The photosensor pixel 27 on which the light 151b is incident leaks electric charge in accordance with the intensity of the light 151b and the exposure time. The gate terminal voltage of the second TFT 62b changes corresponding to the amount of charge leakage, and the on / off state of the second TFT 62b is determined. Since the light reflected by the object 141 has an intensity distribution for each part, each photosensor pixel 27 reacts according to the intensity, and an image distribution corresponding to the object 141 can be formed.

  The above is an embodiment in which the image 151 is formed by the photosensor 64 by irradiating the object 141 with the light 151 from the backlight 146.

(3) Second Reading Operation of Object 141 FIG. 23 is a diagram in which external light 151a is blocked by the object 141, a shadow and a light irradiation unit are formed by the photosensor 64, and an image distribution of the shadow of the object 141 is formed. is there. The outside light 151 is room light, sunlight, or the like.

  As shown in FIG. 23, the outside light 151 a where there is no object 141 enters the photosensor pixel 27 as it is. The photosensor 64 of the incident photosensor pixel 27 leaks electric charge according to the intensity of the external light 151a. In most cases, the photosensor pixel 27 on which the external light 151a is incident discharges the charge, and the second TFT 62b is turned off.

  On the other hand, as shown in FIG. 23, since the external light 151a does not enter the place where the object 141 exists, the external light does not enter the B position. Therefore, the photosensor 64 of the photosensor pixel 27 at the B position hardly leaks charges. In most cases, the photosensor pixel 27 holds electric charge, and the second TFT 62b is turned on. Accordingly, the external light 151a can be blocked by the object 141, the shadow and the light irradiation unit can be formed by the photosensor 64, and the shadow image distribution of the object 141 can be formed.

(4) Reading operation by optical pen FIG. 24 irradiates the photosensor pixel 27 with the light 151b from the optical pen 171 that generates light, and the photosensor 64 detects coordinates.

[3] Image Capture Method of Liquid Crystal Display Device Next, an image capture method in the liquid crystal display device will be described.

  In the image capturing method of this embodiment, when the array substrate 11 of the liquid crystal display device is touched or covered with an object such as a finger, a shadow is formed at that position. For this reason, this shadow is detected by a plurality of photosensor pixels 27 arranged in a matrix on the array substrate 11, and the position thereof is specified.

(1) ON output region and OFF output region First, the ON output region and OFF output region which are the premise of the description will be described with reference to FIG.

  As shown in FIG. 15A, when the photosensor pixel 27 is covered with an object such as a finger, a shadow is formed, the leak from the photosensor 64 is eliminated, the capacitor 63 is charged, and the gate terminal voltage of the TFT 64b increases. Then, the TFT 64b is turned on. A planar region in which the photosensor pixels 27 having the TFTs 64b in the on state are gathered is referred to as an on output region.

  As shown in FIG. 15B, when external light enters the photosensor pixel 27 covered with an object such as a finger, there is a leak from the photosensor 64, the precharge voltage from the capacitor 63 is discharged, and the TFT 64b The gate terminal voltage of the TFT 64b drops, and the TFT 64b is turned off. A planar region in which the photosensor pixels 27 having the TFT 64b in the off state are gathered is referred to as an off output region.

(2) ON Output Area and Shadow FIG. 16 shows a state where the finger 671 touches the display area 10, that is, the formation area of the photosensor pixel 27. In addition, as illustrated in FIG. 16, an example in which the external light 151 is shielded by the finger 671 and the shadow of the finger is detected is described as an example. In FIG. 16A1, ON output regions 601a and 601b are generated. On the other hand, the ON output region 601 does not occur at all in FIG.

  The ON output area 601a in FIG. 16A1 is the shadow of the actual finger 671a. In the display area 10 in which the photosensor pixels 27 are formed in a block shape by the finger 671, an area irradiated with the external light 151 and a light shielding area by the finger 671 are generated. The second TFT 62b, which is the N-channel transistor of the photosensor pixel 27 in the shaded region, is turned on, and an on output is output. This range is the above-described ON output area 601. In FIG. 16 (a1), the original finger 671 also has an intensity distribution of the external light 151, and the ON output region 601b is generated. Since the ON output areas 601a and 601b are also substantially circular, the ON output area 601a has a center coordinate 602a, and the ON output area 601b has a center coordinate 602b. The center coordinates 602 are obtained from line segments having a plurality of diameters by approximating the outline of the ON output area 601 as a circle.

(3) Calibration In the present embodiment, calibration is performed in order to specify one ON output region 601 and specify its position.

  In FIG. 16A1, the precharge voltage Vprc is lowered. The exposure time is kept constant. As shown in FIG. 17, the precharge voltage Vprc is controlled by the photosensor processing circuit 18 by the electronic volume 261a. The precharge voltage Vprc is changed in constant increments, such as in increments of 0.1V. The rate of change is determined from the area of the ON output region 601.

  The number of steps of the precharge voltage Vprc is set to 64 steps or more. The variable range is 1V or more. Moreover, it is 3V or less. When the ON output region 601 is large, the variable width of the precharge voltage Vprc that is changed at a time is increased. When the ON output region 601 is small, the variable width of the precharge voltage Vprc that is changed at a time is reduced.

  The area of the ON output region 601 is the number of ONs of the second TFTs 62 b of the photosensor pixels 27 in the display region 10. That is, the area of the ON output region 601 can be obtained by counting the number of ONs of the second TFTs 62b of the photosensor pixels 27 in the display region 10. It is easy to count the number that is on. This is because the output of the comparator 233 of each photosensor output signal line 25 may be counted.

(4) Data conversion by the comparator In this embodiment, since the output of the data signal applied to the photosensor output signal line 25 is binarized by the comparator 233, the number counting is easy.

  In FIG. 16, the ON output area 601 is displayed in the display area 10, but this is for ease of explanation. The display area 10 in FIG. 16 is a data array obtained by processing the output of the photosensor 27 in a block shape. By explaining this data arrangement in conformity with the display area 10, it becomes easy to understand the situation or occurrence of shadows.

(5) Operation and processing by precharge voltage The precharge voltage Vprc is lowered and the ON output region 601 is measured. The area of the ON output region 601 is reduced by the decrease of the precharge voltage Vprc. The precharge voltage Vprc is lowered until the ON output region 601b is erased. Further, preferably, as shown in FIG. 16A2, the precharge voltage Vprc is decreased until the ON output region 601b is erased and the ON output region 601a becomes a single isolated substantially circular shape.

  For example, as shown in FIG. 18, the ON output region 601a varies depending on the magnitude of the precharge voltage Vprc. When the precharge voltage Vprc is high, an ON output region 601a having a large area is formed by the shadow of the finger 671 as shown in FIG. Further, the ON output area 601 a is in contact with one side of the display area 10.

  When the precharge voltage Vprc is lowered, the area of the ON output region 601a is reduced. When the on-output area 601a is reduced, the on-output area 601a is separated from one side of the display area 10 as shown in FIG. In the ON output area 601a of FIG. 18B, two points of the coordinate center 602a and 602b are generated.

  When the precharge voltage Vprc is further reduced, the area of the ON output region 601a is further reduced. When the ON output area 601a is further reduced, as shown in FIG. 18C, the ON output area 601a becomes nearly circular and the coordinate center becomes one point of 602a.

  When the precharge voltage Vprc is lowered to the state shown in FIG. 18C, the calibration is completed. In the above embodiment, calibration is performed by changing the precharge voltage Vprc.

  Note that the precharge voltage Vprc is changed in accordance with the intensity of the external light 151 as described with reference to FIG. In particular, the initial value is set based on the intensity of outside light. Further, values (precharge voltage Vprc, exposure time Tc, etc.) obtained in the previous calibration are stored in memory, and these values are used as initial values.

(6) Processing of Photo Sensor Processing Circuit 15 The photo sensor processing circuit 15 obtains photo sensor output information from the display area 10 via the comparator 233, and detects the area of the ON output area 601 and the center coordinate value 602. Also, calibration is performed.

  As shown in FIG. 19A, the photo sensor processing circuit 15 sends a center coordinate value (X coordinate value, Y coordinate value: X and Y are 8 bits each) to a microcomputer (not shown). Also, 8 bits of the status signal IST are sent to the microcomputer. As shown in FIG. 19B, the IST information includes the calibration of the code 1 and the detection of the coordinates of the code 2.

  Further, as shown in FIG. 20B, information related to the ON output area 601 is also sent to the microcomputer. For example, the code 0 is that there is no ON output area 601. Code 1 is that the area of the ON output region 601 is larger than a predetermined value. Code 2 indicates that the area of the ON output region 601 is within a predetermined value range. Code 3 is information that the area of the ON output region 601 is smaller than a predetermined value, and therefore calibration should be performed. Code 4 is information that there are a plurality of center coordinates.

[4] Correction of characteristic variation (1) Problem and outline of correction Photosensor 64 of photosensor pixel 27, second TFT 62b, and the like have large characteristic variations. Therefore, even when the same external light is irradiated to the photosensor 64 or the like, there is a second TFT 62b that is in an off state and a second TFT 62b that is kept in an off state.

  In order to solve this problem, as shown in FIG. 25, the display area 10 in which the photosensor pixels 64 are formed is divided into a plurality of processing blocks 881, and processing is performed with each processing block as one change. For example, in the display screen 10 composed of horizontal 240 RGB × 320 dots, it is decomposed into processing blocks of horizontal 16 RGB and vertical 16 dots. That is, since 240RGB / 16RGB = 15 and 320/16 = 20 in the vertical direction, a processing block 881 of 15 × 20 = 300 is configured in the display area 10.

  Accordingly, one processing block 881 has pixels of 16 RGB × 16 dots. Assuming that one photosensor 27 is formed of RGB, one processing block 881 forms a 16 × 16 photosensor.

  In the following description, for ease of explanation, it is assumed that one photosensor 27 is formed of RGB. That is, if 240 RGB × 320 dots, 240 × 320 photosensors are formed.

(2) Number of pixels in processing block 881 The number of pixels in processing block 881 is preferably a power of two. For example, if the processing block is 16 × 16 = 256, this is a multiplier of 2 and meets the condition.

  Further, it is preferable that the number of vertical and horizontal dots of one processing block be a multiplier of 2. In particular, a multiple of 4 is preferable. For example, 4, 8, and 16. That is, one processing block 881 is divided into 4x4, 8x8, and 16x16. Of course, 8x4, 16x8, etc. may be used. This is because by using a multiple of 4, the use efficiency of the number of bits to be expressed is improved. For example, in 16 × 16, since 16 × 16 = 256, the number of photosensors 64 that are turned on or off is 0 to 255. Therefore, it can be expressed by 8 bits. Since 8 × 16 = 128, it can be expressed by 7 bits. By configuring so that the space occupied in the bit length in each state is reduced, the memory size can be reduced, and the IC size can be reduced.

  However, the present embodiment is not limited to this, and one processing block 881 may be divided into 4 × 4, 6 × 6, 8 × 8, 10 × 10, 12 × 12, and 16 × 16.

(2) Processing Block Embodiment FIG. 25B is an embodiment in which the processing block is 16 × 16. In this embodiment, this processing block is used as one judgment value. For example, if the determination value is 50 and the number of photosensors 27 that are turned on in a processing block of 16 × 16 configuration is 50 or more, this processing block 881 is treated as ON. If it is 49 or less, this processing block 881 is treated as OFF. Therefore, if a processing block of 15 × 20 is configured in the display area 10, the number obtained by adding the ON number and the OFF number is 15 × 20 = 300. Further, it is determined whether or not the finger 671 has touched in each processing block 881 unit.

  Since the characteristics of the photosensor 27 and the like vary, whether the photosensor 27 is turned on or off even when the same light is irradiated depends on the characteristics of the photosensor or the like. However, if processing is performed in units of the processing block 881 as shown in FIG. 25, since many photosensor pixels 27 are formed in each processing block 881, they are averaged. Therefore, in the unit of the processing block 881, stable on / off determination can be performed regardless of the characteristics of the photosensor pixel 27 and the like.

(3) Adjustment of the number of photosensor pixels 27 in the processing block 881 (3-1) Dependence on external light intensity The number of photosensor pixels 27 in the processing block 881 varies depending on the light to be detected (hereinafter referred to as external light intensity). You may let them. FIG. 26 shows an embodiment thereof.

  In FIG. 26, the maximum number of photosensor pixels 27 in the processing block 881 is 10 × 10, and the minimum number is 4 × 4. In FIG. 26, the number of photosensors constituting one processing block 881 is reduced as the external light intensity increases. As the external light intensity becomes weaker, the number of photosensors constituting one processing block 881 is increased. The processing block 881 is virtual. By changing the arithmetic processing, the number of photosensor pixels 27 in the processing block 881 can be easily changed. Further, the number of processing blocks 881 in the display area 10 changes due to a change in the number of photosensor pixels 27 in the processing block 881. As the external light intensity increases, the number of processing blocks 881 in the display area 10 increases. As the external light intensity decreases, the number of processing blocks 881 in the display area 10 decreases.

(3-1) Dependence on Finger Input and Light Pen Input Of course, the photo sensor pixel 27 in one processing block 881 may be changed without depending on the external light intensity.

  For example, when inputting with the light pen 171, the processing block 881 is reduced to 4 × 4 or the like, and when inputting with the finger 671, the processing block 881 is increased to 16 × 16.

  As shown in FIG. 24, in the case of the input of the light pen 171, resolution is necessary because character input or the like is performed. Therefore, the size of the processing block 881 is reduced to increase the resolution.

  As shown in FIGS. 22 and 23, when the finger 671 is input, only the presence or absence of the shadow or reflected light of the finger 671 is detected, and therefore no resolution is required. It is important to reliably detect the presence or absence of the finger 671 or the like. Therefore, the processing block 881 is enlarged to reduce the influence of the characteristic variation of the photosensor 64.

  When the input is performed by irradiation with the light 151 like the light pen 171, the size L1 of the processing block 881 is reduced, and when the shadow input or the reflected light is detected like the finger 671, the size of the processing block 881. Increase the length L2. That is, a relationship of L1 <L2 is established. Note that L1 and L2 are preferably configured to be variable depending on the intensity of external light or the like.

(3-3) Correction by Position In addition, the number of photosensor pixels 27 occupied by the processing block 881 may be changed in the central portion and the peripheral portion of the display area 10.

  For example, the processing block 881 is 4 × 4 (the number of photosensor pixels is 16) in the central portion of the display area 10, and the processing block 881 is 16 × 16 (the number of photosensor pixels is 256) in the peripheral portion of the display area 10. This is because a resolution is required at the center of the display area 10 and no resolution is required at the periphery of the display area 10. Further, the peripheral portion of the display area 10 is affected by the sneak light from the backlight 146, and it is necessary to increase the number of photosensor pixels 27 occupied by the processing block 81.

  Further, in the display area 10, the resolution of the processing block 881 in the area where the input of the finger 671 is required may be increased, and the resolution of the processing block 881 in other places may be decreased. That is, the size, resolution, and the like of the processing block 881 at a necessary part and an unimportant part are changed.

  As described above, the size L1 of the processing block 881 at the center of the display area 10 is reduced, and the size L2 of the processing block 881 at the periphery of the display area 10 is increased. That is, a relationship of L1 <L2 is established. Note that L1 and L2 may have no boundary between L1 and L2, or may form a plurality of boundaries. For example, the number of the photosensor pixels 27 in the processing block 881 in the center of the display area 10 is 4 × 4, the number of the photosensor pixels 27 in the processing block 881 in the outermost periphery of the display area 10 is 16 × 16, and a processing block between 16 × 16 and 4 × 14 881 changes to 12 × 12 and 8 × 8. Further, it is preferable that L1 and L2 be configured to be variable depending on the intensity of external light or the like.

(3-4) Resolution Correction The resolution of the photosensor pixel 27 in the display area 10 may be varied.

  For example, the photosensor pixel 27 is formed in each of the RGB pixels 16 in the central portion of the display area 10 as shown in FIG. In the periphery of the display area 10, one photosensor pixel 27 is formed by the RGB pixels 16 as shown in FIG. 4. The number of the photosensor pixels 27 occupied by the processing block 881 may be the same in the central portion and the peripheral portion of the screen of the display region 10, or the area of the processing block 881 may be the same. Further, the above items may be changed in each area of the display area 10. However, in order to prevent the occurrence of moiré, the arrangement and shape of the black matrix covering the photosensor pixels 27 are matched in the display area 10. A black matrix is also formed at a location where the photosensor pixel 27 is not formed, as with other locations.

(3-6) Correction of sensitivity The sensitivity of the photosensor pixels 27 in the display area 10 may be varied.

  For example, the size of the photosensor 64 of the photosensor pixel 27 is increased at the center of the display area 10 to increase the sensitivity. In the periphery of the display area 10, the size of the photosensor 64 of the photosensor pixel 27 is reduced, and the sensitivity is lowered. Further, the above items may be changed in each area of the display area 10. Further, a weighting process may be performed for each photosensor pixel 27 or for each processing block 881.

(3-7) Correction by External Light When the external light becomes weak, the amount of light incident on the photosensor pixel 27 is reduced, and the characteristic variation of the photosensor 64 with respect to the external light is increased.

  Therefore, when the external light is weak, the on / off determination can be stabilized by increasing the number of the photosensor pixels 27 in the processing block 881.

  When the external light becomes strong, the amount of light flux incident on the photo sensor pixel 27 increases, and the characteristic variation of the photo sensor 64 with respect to the external light decreases. Therefore, when the outside light is strong, the on / off determination can be stabilized even if the number of the photosensor pixels 27 in the processing block 881 is decreased.

(4) ON / OFF determination of processing block 881 (4-1) Basic determination method The ON / OFF determination of processing block 881 is performed as shown in FIG. In FIG. 28A, the processing block 881 is composed of 8 × 8 photosensor pixels 27. That is, the photosensor ON number is 0 to 64. If 0 is an exception, it can be expressed by 6 bits from 0 to 63. The number described in each processing block 881 in FIG. 28A is the number of photosensor pixels 27 in the on state.

  In FIG. 28, it is determined as ON (1) at 55 or more. That is, 55 or more photosensor pixels 27 are on, and the processing block 881 is on (1). Below that, it is off (0). The above 55 values are referred to as “judgment numbers”. In addition, the number of determinations that turn on the second TFT 62b is referred to as “on determination number”, and the number of determinations that turn off the second TFT 62b is referred to as “off determination number”.

(4-2) Example of changing the number of judgments The number of on judgments or the number of off judgments is not one. Needless to say, it may be set in multiple stages.

  For example, when the number of ON judgments is less than 10, the value of the processing block 881 is 0, the number of ON judgments 10 or more and less than 20 is 1, the number of ON judgments 20 or more and less than 30 is 2, and the number of ON judgments 30 or more and less than 40 is 3. For example, the number of ON determinations of 40 or more and 63 or less is 4, for example. That is, a value of 0 to 4 is set as the value of each processing block 81 in FIG.

(4-3) Correction by External Light It is preferable that the number of photosensor pixels 27 determined as the processing block 881 being turned on or off is also changed by the external light intensity. When the outside light is strong, the number of ON judgments of one processing block 881 is set small. When the outside light is weak, the number of ON judgments of one processing block 881 is set large.

  This is because when the outside light is strong, the leak of the photo sensor 64 is large and the second TFT 62b is turned off. Therefore, the stronger the outside light is, the smaller the ON judgment number is set, and conversely, the OFF judgment number is set larger.

  When the outside light is weak, there is little leakage of the photosensor 64, and the ON state of the second TFT 62b is maintained. Therefore, as the external light becomes weaker, the ON determination number is set larger, and conversely, the OFF determination number is set smaller. As described above, according to the present embodiment, the number of ON determinations or the number of OFF determinations is varied in accordance with the intensity of external light (light from the backlight 146, sunlight, etc.).

(4-4) Counting Area It is preferable to limit the area where the photo sensor pixel 27 is counted in the on state or the off state.

  For example, as shown in FIG. 29, the photosensor pixel 27b (shown in black) at the center of the processing block 881 is set as a detection pixel, and the surrounding photosensor pixel 28a (shown in white) is not detected. It is a pixel. That is, the photo sensor pixel 27b at the center of the processing block 881 reacts, and the other photo sensors 27a do not react. Whether to react or not is designated by the control signal processing IC 15.

  Although the photo sensor pixel 27a does not react, the present invention is not limited to this.

  For example, the sensitivity of the photosensor pixel 27a and the photosensor pixel 27b may be different. The sensitivity of the photosensor pixel 27a is set to high sensitivity, and the photosensor pixel 27b is set to low sensitivity. The sensitivity can be easily set by making the number of ON judgments or the number of OFF judgments different between the photosensor pixel 27a and the photosensor pixel 27b. Further, the precharge voltage Vprc may be changed in the photosensor pixels 27a and 27b. The comparator voltage may be changed. Further, the size of the photo sensor 64 may be changed in advance by the photo sensor pixels 27a and 27b.

(4-5) Reaction of only the central portion If the photosensor pixel 27b that reacts only to the central portion of the processing block 881 is arranged, it is possible to prevent the reaction unless the finger 671 touches the central portion.

  As shown in FIGS. 30A, 30B, and 30C, the photo sensor 27b forming range to be detected or the photo sensor can be varied.

  In FIG. 30A, the photosensor pixel 27b in the small area at the center of the processing block 881 reacts.

  In FIG. 30C, the photo sensor pixel 27b in a wide area of the processing block 881 reacts.

  In addition, as illustrated in FIG. 30D, the photosensor pixels 27b that react may be dispersedly arranged.

  As shown in FIG. 30E, a photo sensor pixel 27b that reacts in a plurality of processing blocks 881 may be formed. Further, when a reaction location is configured or formed by a plurality of processing blocks 881, all the photosensor pixels of a certain processing block 881 may be used as the photosensor pixels 27b that react.

(5) Canceling the influence of the video signal In order to cancel or reduce the influence of the video signal, the precharge voltage Vprc may be changed. The video signal (gradation signal) affects the output value of the second TFT 62b and the like. Therefore, it is preferable to change the precharge voltage Vprc for the video signal as shown in FIG. In FIG. 27, the horizontal axis is the gradation number.

(6) Arrangement of Comparator 233 In the processing block 881, comparators 233 corresponding to the respective processing blocks 881 are arranged as shown in FIG.

  Of course, the comparator 233 may be arranged for each photosensor pixel 27 of the processing block 881. When the comparator 233 corresponding to the processing block 881 is disposed, a selection circuit that selects the photosensor pixel 27 of the processing block 881 and connects to the comparator 233 is configured. The output of each comparator 233 is selected by the switching circuit 81 and output from the Vout terminal.

(7) Shape of Processing Block 881 As shown in FIG. 39, the processing block 881 may be divided into processing blocks 881A, 881B, 881C in the horizontal direction. The processing block 881 is composed of a plurality of pixel rows.

  The plurality of pixel rows need not be continuous, and may be composed of odd or even pixel rows.

  Moreover, you may divide into the vertical direction. That is, the processing block 881 is composed of a plurality of pixel columns. As shown in FIGS. 41A and 41B, the processing block 881 is preferably configured so that the size can be varied.

(8) Mixing of Reactive Photosensor Pixels 27b and Non-Reactive Photosensor Pixels 27a Further, as shown in FIG. 44, each processing block 881 is configured so that a non-reactive photosensor pixel 27a can be designated. It is preferable.

  “Not responding” is exemplified by a configuration in which the photosensor pixel 27 does not respond to the light 151 or the like. In addition, although the photosensor pixel 27 is configured to react to the light 151 and the like, a method in which no arithmetic processing is performed is exemplified.

  “React” is exemplified by the photosensor pixel 27 reacting to the light 151 and the like, causing a leak and the like, and constituting an on region or an off region. In addition, the photosensor pixel 27 is exemplified by a method of performing arithmetic processing with a configuration that reacts to the light 151 and the like.

  FIG. 44A shows that the photosensor pixel 27b (shown by diagonal lines) at the center of the processing block 881 is designated as “react”. The peripheral photo sensor pixel 27a is designated as “not responding”.

  FIG. 44B shows that the photosensor pixels 27b (shown by diagonal lines) are designated to “react” in the processing block 881 in a distributed manner.

  As shown in FIG. 48, the processing block 881 may be configured so that a “reactive” processing block 881b and a “non-reactive” processing block 881a can be designated for each processing block 881. Each processing block 881 is configured so that a “reactive” processing block 881b and a “non-reactive” processing block 881a can be designated in accordance with a number or icon display displayed on the image display unit 10.

(9) Implementation of Calibration As shown in FIG. 47, a processing block 881 for performing calibration may be set as a function of the processing block 881.

  FIG. 47A is an example in which two calibration areas 881 a and 881 b are provided in the display area 10. Calibration is performed by pressing a finger against the calibration areas 881a and 881b.

  FIG. 47B shows an example in which five calibration areas 881 a, 881 b, 881 c, 881 d, and 881 e are provided in the display area 10. Calibration is performed by pressing a finger against any of the calibration areas 881a to 881e.

  Of course, as shown in FIG. 44, the processing block 881 of FIG. 47 may be configured so that a “reactive” processing block 881 and a “non-reactive” processing block 881 can be designated for each processing block 881.

  47 and 48, each of the processing blocks 881a to 881e may have another function. For example, the processing block 881a is set as the calibration start input area, and the processing block 881b is set as the calibration end input area. The processing block 881c is an area for inputting the start of recalibration. The processing block 881d is a variable start area of the exposure time Tc. The processing block 881e is a double-click input area.

  Note that the processing block 881 is not limited to a rectangular range. Other shapes or arrangements such as circular or hexagonal shapes may be used. Further, the shape of the processing block 881 may be changed in accordance with other factors such as the processing content or the intensity of external light. Moreover, even if it is a rectangle, the range may be changed or dispersed (the area is divided into a plurality of areas).

(10) Adjustment of Precharge Voltage Vprc and Comparator Voltage Vref As shown in FIG. 31, it is preferable to change the precharge voltage Vprc and the comparator voltage Vref in conjunction with each other.

  Further, the precharge voltage Vprc is set higher as the external light intensity increases. However, it is not limited to changing linearly, and may be changed nonlinearly. Moreover, you may change in steps.

  The same applies to the comparator voltage Vref.

  Alternatively, the precharge voltage Vprc may be linearly related to the external light, and the comparator voltage Vref may be changed stepwise. Of course, there are certain cases.

  FIG. 31 shows a case where the second TFT 62b of the photosensor pixel 27 is an N channel. In the case where the second TFT 62b is an N-channel transistor, the precharge voltage Vprc is higher when the external light is strong than when the external light is weak.

  Conversely, when the second TFT 62b is a P-channel transistor, the precharge voltage Vprc is lowered when the external light is strong than when the external light is weak.

  The precharge voltage Vprc is calibrated to determine an appropriate precharge voltage Vprc. As shown in FIG. 32, during calibration, a voltage at which the outputs of all the photosensor pixels 27 are turned on (saturation level voltage) and a voltage at which the outputs of all the photosensor pixels 27 are turned off (off level voltage). Measure against external light intensity. The precharge voltage Vprc sets the median value of the saturation level voltage and the off level voltage.

  The voltage to be set has a range. This is because an appropriate setting value varies depending on the intensity of outside light. As a result of many studies, the precharge voltage Vprc to be set is preferably set to (saturation level voltage−off level voltage) × A + off level voltage. Note that the value of A is set to a value between 0.2 and 0.9. More preferably, the value of A is preferably 0.3 or more and 0.8 or less.

  The comparator voltage Vref may be adjusted with a volume VR as shown in FIG. The volume is configured or configured to be adjusted automatically or manually by the user. A comparator voltage Vref is generated by the volume VR and applied to each comparator 233.

  Further, the comparator voltage Vref may be generated by an electronic volume 261 as shown in FIG. The electronic volume 261 is applied with 8-bit digital data VDATA corresponding to the comparator voltage Vref to be generated. VDATA is given by information from an external light sensor.

(11) Setting of precharge voltage (11-1) Setting by Newton method Setting of the precharge voltage Vprc is performed by applying the Newton method of FIG. The lines in each figure in FIG. 35 indicate that the voltage is higher at the top of the page, and the voltage is lower at the bottom of the page. The subscript of each voltage V indicates the order of voltages to be applied.

  In FIG. 35, calibration is performed by applying voltages in the order of (a), (b), (c), and (d). First, as shown in FIG. 35A, the V0 voltage is applied, and the on / off output state of the photosensor pixel 27 is detected. When the on / off state is not within the shaded area in FIG. 32, the V1 voltage is applied. If the on / off output state of the photosensor pixel 27 in the state where the V0 voltage is applied is within the shaded range in FIG. 32, V0 becomes the value of the calibration voltage. If neither is within the range, the V1 voltage is applied to detect the on / off output state of the photosensor pixel 27. If the on / off output state of the photosensor pixel 27 with the V1 voltage applied is within the hatched range in FIG. 32, V1 becomes the value of the calibration voltage.

  When the on / off state at the time of applying the V1 voltage is not within the hatched area in FIG. 32, the process proceeds to FIG. In FIG. 35B, the V2 voltage is applied. The V2 voltage is calculated as V2 = (V1−V0) / 2. A V2 voltage is applied to detect a change in the on / off output state of the photosensor pixel 27. If the on / off output state of the photosensor pixel 27 with the V2 voltage applied is within the hatched range in FIG. 32, V2 is the value of the calibration voltage.

  When V2 is not within the shaded area, it is determined whether the on / off state when the V2 voltage is applied or the on / off state when the V1 voltage is applied is closer to the target calibration state of the shaded line in FIG. judge. Further, it is determined whether the on / off state at the time of applying the V2 voltage or the on / off state at the time of applying the V0 voltage is closer to the target calibration state of the hatched area in FIG.

  If it is determined that there is a hatched range in FIG. 32 between V2 and V0, the state shifts to the state in FIG. In FIG. 35C, the V3 voltage is applied. The V3 voltage is calculated as V3 = (V2−V0) / 2. A change in the on / off output state of the photosensor pixel 27 is detected by applying the V3 voltage. If the on / off output state of the photosensor pixel 27 with the V3 voltage applied is within the hatched range in FIG. 32, V3 becomes the value of the calibration voltage.

  When V3 is not within the hatched range, it is determined whether the ON / OFF state when the V3 voltage is applied or the ON / OFF state when the V2 voltage is applied is closer to the target calibration state of the hatched line in FIG. judge. Further, it is determined whether the ON / OFF state when the V3 voltage is applied or the ON / OFF state when the V0 voltage is applied is closer to the target calibration state indicated by the hatching in FIG.

  When it is determined that there is a hatched range in FIG. 32 between V2 and V3, the state shifts to the state in FIG. In FIG. 35D, the voltage V4 is applied. The V4 voltage is calculated as V4 = (V2−V3) / 2. The V4 voltage is applied to detect a change in the on / off output state of the photosensor pixel 27. If the on / off output state of the photosensor pixel 27 in the state where the V4 voltage is applied is within the hatched range in FIG. 32, V4 becomes the value of the calibration voltage.

  A target calibration voltage can be obtained by sequentially performing the calibration adjustment described above.

  The above operation is shown in FIG. The precharge voltage Vprc for performing the calibration is repeatedly increased and decreased to approach the target value sequentially. The voltage to be applied is not constantly changing as shown in FIG. 36, and it is preferable that the voltage to be applied is driven so as to be maintained for a certain period of time with a large and small precharge voltage Vprc as shown in FIG.

  In FIG. 36, the precharge voltage Vprc starts from 2 V, and the number (number of on pixels) in which the TFT 62c of the photosensor pixel 27 of each processing block 881 is kept on or the photosensor pixel corresponding to the precharge voltage Vprc. The number of 27 TFTs 62c changed to the off state (the number of off pixels) is counted. When the number of on pixels or the number of off pixels is not within the specified range, the precharge voltage Vprc is increased or decreased (see FIG. 35). In FIG. 36, the precharge voltage Vprc is increased to 6V. The precharge voltage Vprc is updated, and in the updated state, the number of off pixels or the number of on pixels is counted. The count value is compared with the previous count value to determine whether it is approaching the specified range, and the next precharge voltage Vprc is set. If the counted value is not within the predetermined range, the precharge voltage Vprc is changed. With the above operation, the range of change of the precharge voltage Vprc is narrowed as shown in FIG. Due to the change in the precharge voltage Vprc, the number of on pixels or the number of off pixels falls within a specified range at point A, and the precharge voltage Vprc is fixedly set. The precharge voltage Vprc (about 3.25 V) is implemented when the external light intensity changes a predetermined amount. Of course, you may carry out always. However, it is preferable not to perform calibration or to stop when contact determination and contact detection are performed.

  As shown in FIG. 37, the change in the precharge voltage Vprc is achieved by fixing the voltage value for a certain period at the maximum position and the minimum position of each change, or by loosening the change so that the number of on pixels or off pixels is increased. It is preferable to improve the variation accuracy of whether or not it is within a specified range.

(11-2) Other Setting Method FIG. 35 shows a calibration method using the Newton method. However, the present embodiment is not limited to this. The target precharge voltage Vprc may be obtained by adjusting or controlling the applied voltage from the number of on / off states of the photosensor pixel 27 (number of on pixels, number of off pixels).

  For example, as shown in FIG. 38A, application of the precharge voltage Vprc changes the on-off difference (difference between the number of on pixels and the number of off pixels) as shown in FIG. 38B. When the precharge voltage Vprc is very high, 100% of the photosensor pixels 27 are turned on. The off-output photosensor pixel 27 is zero. Therefore, the on-off difference is 100-0 = 100. When the precharge voltage Vprc is very low, 100% of the photosensor pixels 27 are turned off. The on-output photosensor pixel 27 is zero. Therefore, the on-off difference is 0-100 = -100.

  Assuming that the precharge voltage Vprc is close to the target value and the target setting is when the number of on and off of the photosensor pixel 27 is equal, 50% of the photosensor pixel 27 is off output. The on-output photosensor pixel 27 is 50%. Therefore, the on-off difference is 50-50 = 0.

  As described above, calibration can be performed by changing the precharge voltage Vprc to a large or small value during calibration and monitoring whether the on-off number approaches or moves away from the target value.

(11-3) Change Rate of Precharge Voltage As shown in FIG. 38, the change rate of the precharge voltage Vprc may be increased at the beginning and may be decreased as the target value is approached. This is because in the final target state, the number of changes in the on / off output of the photosensor pixel 27 is reduced, and accuracy is required.

  As shown in FIG. 58, the change rate of the precharge voltage Vprc is preferably changed in accordance with the intensity of external light. When the outside light is strong, the magnitude of change is increased and the rate of change is also increased. Conversely, when the outside light is weak, the amount of change is reduced and the rate of change is also reduced.

(11-4) Calculation of the number of ON pixels and the number of OFF pixels at a fixed ratio In FIG. 38, the number of differences between the number of ON pixels and the number of OFF pixels is obtained. However, the present embodiment is not limited to this. .

  A certain ratio of the number of on pixels or the number of off pixels may be obtained. Further, the number is not limited to the ratio, and may be the number of on pixels or the number of off pixels.

  In addition, the number of ON pixels is 0 or the number of OFF pixels is 0 is also included.

  For example, a case where the ratio of the number of ON pixels to the total number of pixels is controlled to be in a range of 1 to 2% by applying the precharge voltage Vprc is exemplified. Moreover, it is exemplified that the ratio of the number of on-pixels is controlled to be in a range of 10 to 20%. Further, it is exemplified that the ratio of the number of on-pixels is controlled to be 5% or less. In addition, an example in which the ratio of the number of ON pixels is 90% or more is illustrated. An example in which the ratio of the number of off pixels is 90% or more is illustrated.

  Further, the control is exemplified so that the number of ON pixels is 100 or more. In addition, the control is exemplified such that the number of ON pixels is 100 or more and 1000 or less. In addition, an example in which the ratio of the number of ON pixels is 100,000 or more is exemplified. An example in which the number of off pixels is 1000 or less is illustrated.

(11-5) Other Modifications In the above embodiment, the number of on pixels or the number of off pixels or the ratio of the number of on pixels to the number of off pixels is more than a certain value or less or within a certain range based on the precharge voltage Vprc. It was something to control inside. However, the above control can also be realized by adjusting the exposure time Tc. Therefore, it goes without saying that the precharge voltage Vprc may be replaced with the exposure time Tc in the above embodiment. It can also be realized by the comparator voltage Vref. Therefore, it goes without saying that the precharge voltage Vprc may be replaced with the comparator voltage Vref in the above embodiment. Also, a plurality of precharge voltages Vprc, exposure time Tc, and comparator voltages Vref may be combined.

(12) Light receiving sensor 1192
(12-1) Sensitivity to external light intensity The sensitivity of the photosensor 64 to external light intensity varies depending on the color temperature of the external light 151. The photosensor 64 has a short wavelength and high sensitivity. That is, the sensitivity is high in blue (region where the color temperature is high) and low in red (region where the color temperature is low). Therefore, it is necessary to calculate the intensity of external light according to the characteristic sensitivity of the photosensor 64, not the intensity of human visual sensitivity. That is, it is necessary to perform calibration or the like corresponding to the color temperature of external light.

  In response to this problem, the present embodiment arranges a plurality of light receiving sensors 1192 as shown in FIG. A color filter 1191 is disposed at the light incident portion of the light receiving sensor 1192.

  In FIG. 56, the light receiving sensors 1192 (1192R, 1192G, 1192B) have sensitivity curves in the same wavelength band. Red (R), green (G), and blue (B) color filters 1191 are disposed on the incident side of the light receiving sensor 1192. The light receiving sensor 1192R is for a long wavelength. The light receiving sensor 1192B is for a short wavelength. The light receiving sensor 1192G is for a medium wavelength.

  The output of each light receiving sensor 1192 is input to the correction circuit 1193. The correction circuit 1193 corrects the input signal to output the comparator voltage Vref and the precharge voltage Vprc so that the comparator voltage Vref and the precharge voltage Vprc are appropriate. Precharge voltage generation circuit 1194 generates precharge voltage Vprc, and comparator voltage generation circuit 1195 generates comparator voltage Vref.

(12-2) Configuration of Light Receiving Sensor 1192 As shown in FIG. 56, a PIN photodiode is exemplified as the light receiving sensor 1192. The intensity of outside light is detected by a PIN photodiode and amplified by an operational amplifier at an appropriate magnification. In addition, a capacitor or the like is disposed in the signal path to delay the change of external light and to have a hysteresis characteristic.

  These circuits are configured as a matrix circuit 1211, and the matrix circuit 1211 outputs a precharge voltage Vprc corresponding to the processing block 881 formed in a matrix.

  Of course, one precharge voltage Vprc corresponding to the display area 10 may be output. The matrix circuit 1211 can output or generate a plurality of precharge voltages Vprc in one processing block 881 or the display area 10. These precharge voltages Vprc are stored in the matrix circuit 1211.

  As shown in FIG. 54, the external light 151 is received by the photosensor 1171, and the current I generated by the received light is converted into the voltage V by the current-voltage (IV) conversion amplifier 1172. At the same time, the conversion amplifier 1172 generates a comparator voltage Vref and applies it to the comparator 233.

(12-3) Other Configurations of Light Receiving Unit FIGS. 54 and 56 show an embodiment in which a light receiving sensor 1192 (1171) and the like are separately arranged in addition to the display area 10. The present embodiment is not limited to this.

  For example, as shown in FIG. 55, a light receiving portion 1181 may be formed in or near the display region 10 to detect the intensity of external light or the like. The light receiving unit 1181 is preferably configured or formed by the photosensor 64.

  FIG. 55A shows an embodiment in which light receiving portions 1181 (1181a, 1181b) are formed above and below the display area 10. FIG.

  FIG. 551 (b) shows an embodiment in which light receiving portions 1181 (1181a, 1181b, 1181c, 1181d) are arranged at the four corners of the display area. If necessary, a color filter 1191 or the like is disposed in the light receiving unit 1181 as shown in FIG.

  The detection of the incident direction of the external light 151 is also important for determining the coordinate position. For example, as shown in FIG. 57 (b), when the external light 151a enters the object 671 from the left side, the shadow 601a can be formed on the right side of the object. Therefore, when the object is detected, the coordinate position is shifted to the right side. When the external light 151b is incident on the object 671 from the right side, the shadow 601b can be formed on the left side of the object. Therefore, when the object is detected, the coordinate position is shifted to the left side.

  In order to solve this problem, a three-dimensional light receiving sensor 1201 is arranged as shown in FIG. The light receiving sensor 1201 has a configuration approximating a quadrangular pyramid or a cube. In the light receiving sensor 1201, the light receiving portions are formed on four side surfaces and an upper surface as an example. That is, the light receiving part is formed at a plurality of locations.

  When the external light 151a is incident on the object 671 from the left side, the external light 151a is incident on the light receiving unit disposed mainly on the left side. When the external light 151b is incident on the object 671 from the right side, the external light 151b is incident on the light receiving unit disposed mainly on the right side. When the external light 151c is incident on the object 671 from above, the external light 151c is incident on the light receiving unit disposed mainly on the upper side.

  From the above, the light receiving part that is incident mainly differs depending on the incident direction of the external light 151. Therefore, it is possible to detect the incident direction of the external light 151 by detecting which light receiving unit is strongly receiving external light. Therefore, as shown in FIG. 57B, the shadow position can be corrected even if the direction in which the shadow 601 is generated is different.

(12-4) Modified Example In the above embodiment, the precharge voltage Vprc is changed in magnitude and change speed according to the intensity of external light. However, the present embodiment is not limited to this.

  For example, the change rate of the exposure time Tc and the change unit (1H, 2H...) May be varied. Further, both the precharge voltage Vprc and the exposure time Tc may be changed. Further, the comparator voltage may be changed.

(13) Setting of precharge voltage Vprc or the like according to the magnitude of external light In the liquid crystal display device of the present embodiment, an appropriate precharge voltage Vprc, exposure time Tc, comparator voltage, or these depending on the magnitude of external light It is necessary to set a combination. Therefore, in this embodiment, the method illustrated in FIGS. 59 to 63 is performed.

(13-1) Setting in units of horizontal scanning period FIG. 59 shows an embodiment in which the comparator voltage Vref is changed to Vc2, Vc1, and Vc3. In FIGS. 59 and 60, the precharge voltage Vprc, the exposure time Tc, and the like may be changed simultaneously with the comparator voltage Vref. In FIGS. 62 and 63, the precharge voltage Vprc, the comparator voltage Vref, the exposure time Tc, and the like may be changed in synchronization with the base voltage.

  FIG. 59A shows an embodiment in which the comparator voltages Vref = Vc1 and Vc2 are set, and the voltage is switched between Vc1 and Vc2 every 1H (one horizontal scanning period).

  In FIG. 59A, the comparator voltage Vref = Vc1 and Vc2 are switched every 1H. By changing the comparator voltage Vref, the determination level in the comparator circuit 233 changes. Therefore, the magnitudes of Vc1 and Vc2 are changed so that the determination level is appropriate within the Vc1 to Vc2 range of the comparator voltage Vref.

  FIG. 59B is an embodiment in which the comparator voltage Vref is changed in units of 2H. The polarity of the video signal applied to the liquid crystal display panel changes in a 2H cycle (for example, 1H is + polarity and 2H is -polarity). Therefore, as shown in FIG. 59 (b), it is preferable to change in units of 2H (4H period). That is, the comparator voltage Vref, the precharge voltage Vprc, and the exposure time Tc are changed at a cycle that is twice the polarity cycle of the video signal applied to the liquid crystal display panel. That is, if the period of the video signal is 2H, the period is 4H or the period in which one comparator voltage Vref is continuous = the period of the video signal. The change is not limited to 4H, and any change may be used as long as it is a multiple of 2H.

  FIG. 59C shows an embodiment in which the comparator voltage Vref is 3 or more (Vc1, Vc2, Vc3). The comparator voltage Vref is changed every 1H period. In the embodiment of FIG. 59 (c), the change may be made every 2H as in FIG. 59 (b). Further, the effect of FIG. 59B can be realized by any multiple of 2H that is 4H or more.

(13-2) Setting in units of frames FIG. 59 shows the setting of the comparator voltage Vref and the like in units of the horizontal scanning period. However, the present embodiment is not limited to this, and may be set in units of frames as shown in FIG.

  FIG. 60 shows an embodiment in which the comparator voltage Vref is changed to Vc2, Vc1, and Vc3 in one frame. As in FIG. 59, the precharge voltage Vprc, the exposure time Tc, and the like may be changed simultaneously with the comparator voltage Vref.

  FIG. 60A shows an embodiment in which the comparator voltages Vref = Vc1 and Vc2 are set and switched between Vc1 and Vc2 every 1F (one vertical scanning period).

  In FIG. 60A, the comparator voltage Vref = Vc1 and Vc2 are switched every 1F. By changing the comparator voltage Vref, the determination level in the comparator circuit 233 changes. Therefore, the magnitudes of Vc1 and Vc2 are changed so that the determination level is appropriate within the Vc1 to Vc2 range of the comparator voltage Vref.

  FIG. 60B shows an embodiment in which the comparator voltage Vref is changed in units of 2F. The polarity of the video signal applied to the liquid crystal display panel inverts the video signal applied to each pixel row in a 2F cycle. For example, in a certain pixel row, the 1st F changes with + polarity, and the 2nd F changes with −polarity. Therefore, it is preferable to change by 2F units as shown in FIG. That is, the comparator voltage Vref, the precharge voltage Vprc, and the exposure time Tc are changed in a cycle that is twice the polarity cycle of the video signal of each pixel row applied to the liquid crystal display panel. If the period of the video signal is 2F, it is changed at a period of 4F. The change is not limited to 4F, and any change may be used as long as it is a multiple of 2F.

  FIG. 60C shows an embodiment in which the comparator voltage Vref is 3 or more (Vc1, Vc2, Vc3). The comparator voltage Vref is changed every 1F period. In the embodiment of FIG. 60C, the change may be made every 2F as in FIG. Further, the effect of FIG. 60B can be realized by any multiple of 2F that is 4F or more. 59 and 60 may be combined with each other.

(13-3) Example of changing precharge voltage Vprc in five steps FIG. 61 shows an embodiment in which the precharge voltage Vprc is changed from Vp1 to Vp5. In this embodiment, the precharge voltage Vprc is switched every 1H. Note that the types of precharge voltage Vprc are not limited to the five types Vp1 to Vp5. Any of two or more types may be used.

  In FIG. 61A, the precharge voltage Vprc = Vp1 to Vp5 is switched every 1H. By changing the precharge voltage Vprc, the output of the second TFT 62b changes. Therefore, the magnitude of the precharge voltage Vprc is changed so that the number of ON pixels is appropriate in the processing block 881 or the display area 10 within the Vp1 to Vp5 range of the precharge voltage Vprc. The precharge voltage Vprc is sequentially decreased or increased. When calibration is completed, the constant value (+ Vp2 in FIG. 61A) is maintained.

  FIG. 61B also switches the precharge voltage Vprc = Vp1 to Vp5 every 1H. By changing the precharge voltage Vprc, the output of the second TFT 62b changes. Therefore, the magnitude of the precharge voltage Vprc is changed so that the number of ON pixels is appropriate in the processing block 881 or the display area 10 within the Vp1 to Vp5 range of the precharge voltage Vprc. The precharge voltage Vprc sequentially changes up and down and converges to the optimum calibration position. When calibration is completed, a constant value (+ Vp3 in FIG. 61B) is maintained.

  FIG. 61 shows the operation of the precharge voltage Vprc and the like with the horizontal scanning period as a unit. However, the present embodiment is not limited to this, and may be an operation in units of frames as shown in FIG.

(13-4) Change of Base Voltage Vb FIG. 62 shows an embodiment in which the base voltage Vb is changed.

  The base voltage is the GND voltage of the photosensor 64. The base voltage Vb is the potential of the common signal line 31 illustrated in FIG.

  Changing the base potential Vb has the same effect as changing the precharge voltage Vprc and the like in a pseudo manner. This is because the potential applied to the photosensor 64 changes due to the change in the base potential Vb.

  FIG. 62 shows an embodiment in which the base potential Vb is changed from Vp1 to Vp5. FIG. 62 shows an embodiment in which the base potential Vb = Vp1 to Vc5 and the base potential Vb is switched every 1H. Note that the types of base potential Vb are not limited to the seven types of −Vb3 to + Vb3. Any of two or more types may be used.

  In FIG. 62A, the base potential Vb = −Vb3 to + Vb3 is switched every 1H. By changing the base potential Vb, the voltage applied between the terminals of the photosensor 64 changes. Accordingly, the magnitude of the base potential Vb is changed so that the number of ON pixels in the processing block 881 or the display area 10 is appropriate within the range of −Vb3 to + Vb3 of the base potential Vb. The base potential Vb is sequentially decreased or increased. When calibration is completed, a constant value (-Vb2 in FIG. 62A) is maintained.

  FIG. 62B also switches the base potential Vb = −Vb3 to + Vb3 every 1H. By changing the base potential Vb, the output of the second TFT 62b changes. Accordingly, the magnitude of the base potential Vb is changed so that the number of ON pixels in the processing block 881 or the display area 10 is appropriate within the range of −Vb3 to + Vb3 of the base potential Vb. The base potential Vb changes up and down sequentially and converges to the optimum calibration position. When the calibration is completed, a constant value (+ Vb1 in FIG. 62B) is maintained.

  FIG. 62 shows the operation of the base potential Vb and the like with the horizontal scanning period as a unit. However, this embodiment is not limited to this, and may be an operation in units of frames as shown in FIG.

(14) Characteristic inclination in the plane of the display area 10 In the display area 10, the ON / OFF state has an inclination depending on the characteristics of the photosensor 64 and the second TFT 62b. This is because the characteristics often change slowly with in-plane inclination. The change is caused by a gradual change in laser annealing conditions when forming a transistor or the like by low-temperature polysilicon technology.

(14-1) First Correction Method The first correction method of the characteristic gradient is performed as shown in FIG.

  In FIG. 42, as an example, the display area 10 is divided into 3 blocks horizontally and 4 blocks vertically. Processing block 881 is 3 × 4 = 12. For ease of explanation, it is assumed that each processing block 881 is composed of 4 × 4 pixels 16. That is, one processing block 881 is composed of 16 pixels (16 photosensor pixels 27).

  In order to grasp the characteristic inclination in the plane of the display area 10, as shown in FIG. 42, the photosensor pixels 27 formed in the pixel row and the pixel column at the outermost periphery of the display area 10 are used. The characteristic is measured by reading the on / off state of the second TFT 62b of the photosensor pixel 27. Since the reading method has been described before, the description thereof is omitted. In FIG. 42, the on state of the second TFT 62b is 1 and the off state of the second TFT 62b is 0.

  As an example, as shown in FIG. 42A, the pixel column direction is 1111011011100100 on / off from the top. The pixel row direction is 111101111001 from the left. FIG. 42B shows the result of summing up these values for each processing block 881. Aggregation counts the number of ON pixels. In the column direction of the processing block 881, the number of ON pixels is 4, 2, 3, 1, and the row direction is 4, 3, 2. Therefore, the number of ON pixels tends to decrease in the vertical direction of the display area 10 (the number of ON pixels is large in the upper area and the number of ON pixels is small in the lower area), and the number of ON pixels tends to decrease in the horizontal direction ( There are a large number of ON pixels in the left region and a small number of ON pixels in the right region).

  The result of FIG. 42B is stored in the memory, and the number of on pixels or the number of off pixels of each processing block 881 is corrected. In the processing block 881 in the upper left area, even if the number of on-pixels is large in a calibration state with a certain external light intensity, the processing is corrected by processing and the number of on-pixels is reduced. In the processing block 881 in the lower right region, even if the number of on pixels is small in the calibration state with a certain external light intensity, the number of on pixels is increased by processing.

  In FIG. 42, the characteristics of the photo sensor pixels 27 on the left side and the upper side of the display area 10 are measured or grasped and corrected. However, preferably, as shown in FIG. 43, the characteristics of the photosensor pixels 27 on the left side, right side, upper side, and lower side of the display area 10 are measured and corrected.

(14-2) Second Correction Method In FIG. 42, the characteristics of the second TFT 62b and the like at the periphery of the display area 10 are measured to determine the in-plane characteristic inclination. However, the present embodiment is limited to this. It is not a thing.

  You may measure the transistor characteristic of the center part of the display area 10. FIG.

  Further, the characteristic inclination of the entire display area 10 may be measured.

  In the embodiment of FIG. 42, the transistor characteristics are measured using the photosensor pixel 27 in the display area 10 where light detection is performed. However, the present embodiment is not limited to this. For example, a photo sensor pixel 27 that measures transistor characteristics may be formed in addition to the display area 10, and the transistor characteristics of the display area 10 may be estimated using the pixels 27 and the like.

  Further, although the number of ON pixels is counted, the present embodiment is not limited to this. When the output from the photosensor pixel 27 is analog data, the size of the analog data may be added or sample-and-hold processed, and processed as a continuous amount.

(14-2) Other Modifications In this embodiment, the contact determination may be performed by measuring or counting the number of on pixels, or the contact determination may be performed by measuring the number of off pixels.

  In this specification, in order to facilitate the description, it is assumed that the number of on pixels is measured.

  Further, a large number of ON pixels indicates that the leak of the photosensor 64 is small.

  In addition, the precharge voltage Vprc is high, indicating that the second TFT 62b is kept on even if the photosensor 64 has a slight leak.

  Further, a large number of ON pixels indicates that the amount of light irradiated to the photosensor pixel 27 is small.

(15) Relationship between the number of ON pixels and external light intensity The number of ON pixels varies nonlinearly with external light intensity. This is mainly because the leakage amount of the photosensor 64 is often proportional to the external light intensity, but the ON state of the second TFT 62b and the magnitude of the precharge voltage Vprc are in a non-linear relationship. In particular, when the intensity of external light is weak, the precharge voltage Vprc is also lowered. This is because the leak amount of the photo sensor 64 is also small. This is because unless the precharge voltage Vprc is lowered, the difference between the case where the photosensor pixel 27 is shielded from the case where the external light is irradiated cannot be taken.

  FIG. 64 shows the change in the number of on-pixels when the calibration is made constant and the intensity of the external light 151 is changed. The vertical axis indicates the number of ON pixels per unit. Since it is per unit, it indicates a percentage (%) that is a ratio.

  For example, in the external light 0, 60% of the photosensor pixels 27 are in the on state, and the remaining 40% are in the off state. At the precharge voltage Vprc in the same calibration as before, in the external light 400lx, 10% of the photosensor pixels 27 are in the on state, and the remaining 90% are in the off state (off pixels). The number of on pixels + the number of off pixels = the number of photosensor pixels in the display area 10.

  As shown in FIG. 64, the number of on-state pixels (number of on-pixels) hardly decreases in the range of 0 to 100 lx. When the external light becomes stronger than 100 lx, the number of on-state pixels (the number of on-pixels) rapidly decreases. Therefore, the relationship of the number of on-pixels with respect to external light is non-linear.

  When a finger 671 or the like is brought into contact with the display area 10, a shadow is formed on the display area 10. That is, it is shielded from light. Accordingly, the number of photosensor pixels 27 in the light shielding portion that are kept on is increased. In order to determine whether or not there is contact with a finger or the like, this change in the number of ON pixels is monitored. In the following, detection of shadows will be described as an example for ease of explanation.

  The number of on pixels (or the number of off pixels) of the photosensor pixels 27 in the display area 10 changes due to light shielding. The extent to which the number of ON pixels increases (when the percentage of ON pixels reaches) is referred to as the determination threshold number. The judgment threshold number is also expressed as a percentage per unit. The number of determination thresholds is indicated by a dotted line in FIG.

  If the number of determination thresholds is exceeded, it is determined that the light is shielded or control is started. For example, in the embodiment of FIG. 64, it is determined that the light is shielded when the number of determination thresholds is 70 (%) or more at 0lx. The processing method at that time is as described above.

  As described above, in relation to external light, the number of ON pixels per unit (per unit area or per unit processing region) (at the time of light irradiation) and the same unit (per unit area or per unit processing region) The number of ON pixels (at the time of shading) = the number of determination thresholds is in a non-linear relationship.

  For example, in FIG. 64, when the external light is 0 lx, the number of ON pixels is 60%, and the number of determination thresholds is 70%. The ratio is 70/60 = 1.67. When the external light is 400 lx, the number of on-pixels is 10%, and the determination threshold number is 50%. The ratio is 50/10 = 5.0. That is, the ratio of the number of determination thresholds / the number of ON pixels at an arbitrary external light intensity is varied. The ratio of the number of determination thresholds / the number of on pixels is made smaller as the external light becomes weaker.

  The determination threshold number is set in advance by measuring the characteristics of the photosensor pixels 27 in the display area 10. Moreover, you may comprise so that a user can change with use environment conditions. Alternatively, the intensity of external light or the intensity of the backlight may be automatically detected to set the determination threshold number.

  The above matters are the same when inputting coordinates with a light pen. It is configured such that the number of determination thresholds can be set by detecting or controlling the number of on-pixels (number of off-pixels) based on the amount of light emitted from the light pen.

(16) Plural application of precharge voltage (16-1) First application method In order to better capture an image, a plurality of precharge voltages Vprc can be applied as shown in FIG. It is preferable.

  In FIG. 45, the precharge voltage Vprc1 is configured to be applied to an odd-numbered pixel column by turning on / off the switch SW1. Further, the precharge voltage Vprc2 can be applied to the even-numbered pixel columns by turning on / off the switch SW2.

  Depending on the magnitude of the precharge voltage Vprc, the on / off state of the photosensor pixel 27 changes even with the same external light intensity. The higher the precharge voltage Vprc, the more the photosensor pixel 27 is kept on. The lower the voltage, the easier it is to turn off the precharge voltage Vprc. Therefore, the photosensor pixel 27 to which the low precharge voltage Vprc is applied is turned off even with weak external light.

  By applying the precharge voltage Vprc to the pixel as shown in FIG. 45, it is possible to capture an image or detect coordinates in a wide range from the low external light range to the high external light range.

  In FIG. 45, a plurality of types of comparator voltages Vref are generated and can be applied to the comparator 233. The comparator voltage Vref1 is applied to the comparator 233b arranged in the even pixel column. The comparator voltage Vref2 is applied to the comparator 233a arranged in the odd pixel column. By applying a plurality of comparator voltages Vref to the pixels as shown in FIG. 45, it becomes possible to perform image capture or coordinate detection in a wide range from the low external light range to the high external light range.

(16-2) Second Application Method As shown in FIG. 46, photosensor pixels 27 having different sensitivities may be arranged in the pixel column direction. Moreover, you may combine with embodiment of FIG. In FIG. 46, the photosensor pixel 27a having high sensitivity (that can detect light up to low illuminance) is described as a large sensor. The photo sensor pixel 27b having low sensitivity (reacts only to high illuminance) is described as a small sensor.

  In FIG. 46, as an example, the comparator 233 is configured to be able to distribute and output to eight output signal lines (indicated by a, b, c, d, e, f, g, and h). With this configuration, it is easy to determine the pixel position in the on or off state. Further, the output of the comparator 233 is configured to be held by a capacitor, and a switch S is disposed before and after the capacitor, so that an arbitrary output of the comparator 233 can be sequentially extracted to the outside.

(16-3) Third Application Method In FIG. 67, a plurality of precharge voltages Vprc are applied in the pixel row direction. In FIG. 67, the difference in the magnitude of the precharge voltage Vprc is indicated by numerals 1 to 4. 1 (precharge voltage Vprc1), 2 (precharge voltage Vprc2), 3 (precharge voltage Vprc3), 4 (precharge voltage Vprc4), 1 being the lowest precharge voltage Vprc, and 4 being the highest precharge voltage Vprc. A plurality of precharge voltages Vprc are generated. This is preferably 4 or more, but even if it is 2 or more, it can cope with a relatively wide range of external light. For example, the precharge voltage Vprc has four stages of 2.50V, 2.51V, 2.52V, and 2.53V. The difference between the precharge voltages Vprc is preferably 0.05 to 0.2V.

  In FIG. 67, it is preferable to change the precharge voltage Vprc 1 to 4 for each pixel row. Further, it may be changed every two pixel rows or a plurality of pixels. Changing the precharge voltage Vprc for each pixel row can be performed by one precharge voltage Vprc generation source. This is because the precharge voltage Vprc to be applied may be changed every one horizontal scanning period or every plural horizontal scanning periods.

  As shown in FIG. 67, when different precharge voltages Vprc are set in the pixel row direction and processing blocks 881 are set in a matrix as shown in FIG. 48, one processing block 881 is A plurality of different precharge voltages Vprc are applied.

(16-4) Fourth Application Method The photosensor 64 and the second TFT 62b have characteristic variations due to processes and the like. The characteristic variation is often different in the processing block 881. Therefore, in the processing block 881, the precharge voltage Vprc to be employed according to the characteristic variation is determined at the time of inspection.

  For example, the precharge voltage Vprc1 is set optimal for the processing blocks 1a, 1b, and 2a. In the processing blocks 2a, 2b, and 3c, the precharge voltage Vprc2 is set to be optimum. In the processing blocks 4a, 4b, and 4c, the precharge voltage Vprc3 is set to be optimum. In other processing blocks, the precharge voltage Vprc4 is set to be optimum.

  In each processing block 881, precharge voltages Vprc1 to Vprc4 are applied to the respective pixel rows. The processing blocks 1a, 1b, and 2a select the pixels in the pixel row to which the precharge voltage Vprc1 is applied, and perform approach, contact, and separation processing. The processing blocks 2a, 2b, and 3c select pixels in the pixel row to which the precharge voltage Vprc2 is applied, and perform approach, contact, and separation processes. The processing blocks 4a, 4b, and 4c select the pixels in the pixel row to which the precharge voltage Vprc3 is applied, and perform the approach, contact, and separation processes. The other processing blocks select the pixels in the pixel row to which the precharge voltage Vprc4 is applied, and perform the approach, contact, separation processing, and the like. Each processing block 881 performs a calibration process or the like on a pixel to which the optimum precharge voltage Vprc is applied. When the optimum precharge voltage Vprc cannot be specified as one, a pixel to which a plurality of precharge voltages Vprc is applied is specified, and an averaging process is performed to perform calibration, approach, contact, separation process, etc. .

(16-5) Fifth Application Method A plurality of precharge voltages Vprc may be applied to one pixel and may be changed to perform calibration, approach, contact, separation processing, and the like. For example, the precharge voltage Vprc is changed in each frame. The frame may be changed in a plurality of frames. For example, the precharge voltage Vprc is changed every two frames.

(17) Change in Precharge Voltage and Exposure Time Tc The exposure time Tc may be changed without synchronizing with the change in the precharge voltage Vprc.

  Further, the precharge voltage Vprc and the exposure time Tc may be changed simultaneously.

(17-1) First Operation Method For example, when the precharge voltage Vprc is 3.5 V and the exposure time Tc is 324 H, a change in the number of ON pixels in the processing block 881 is detected (whether the number of ON pixels is 1 or more). For example, the calibration operation may be performed by multiplying the precharge voltage Vprc 4.0V by a constant b. For example, if b = 0.5, the precharge voltage Vprc is 4.0 × 0.5 = 2V. That is, at the time of calibration, the precharge voltage Vprc = 2.0 V and the exposure time Tc = 324H. Note that the change step of the exposure time Tc is preferably 2H or more.

  The operation of detecting the change in the number of ON pixels in the processing block 881 is performed by changing the precharge voltage Vprc = 4.0V and the exposure time Tc = 324H from the start point or the center, and during calibration, the precharge voltage Vprc = 2.0V. The exposure time Tc = 324H is changed as the starting point or the center. This on-pixel count detection operation and the calibration operation are performed alternately.

  Note that “approaching” means detecting that a finger or the like approaches the panel surface.

  “Contact” means that a finger or the like is in contact with the panel surface.

  “Leaving” means detecting separation from a finger or the like on the panel surface.

  Which precharge voltage Vprc or exposure time Tc to use among the precharge voltage Vprc or exposure time Tc applied to the pixel row of each processing block 881 is determined in advance for each processing block 881 when the panel is shipped. It is preferable to store the data in an EEPROM.

(17-2) Second Operation Method The precharge voltage Vprc may be applied to successive pixel rows. Further, the precharge voltage Vprc may be applied randomly to the pixel row. Further, the intensity of the precharge voltage Vprc may be changed at a constant period (two-dimensionally and in the time axis direction). The precharge voltage Vprc applied to each pixel row is changed for each frame.

  The same applies to the exposure time Tc. The exposure time Tc may be applied to successive pixel rows. The exposure time Tc may be applied randomly to the pixel rows. Further, the length of the exposure time Tc may be changed at a constant cycle (two-dimensionally and in the time axis direction). The exposure time Tc applied to each pixel row may be changed for each frame.

  The precharge voltage Vprc and the exposure time Tc may be changed simultaneously. The exposure time Tc and the precharge voltage Vprc may be alternately changed in units of frames or pixel rows.

(17-3) Third Operation Method In FIG. 68, a plurality of precharge voltages Vprc are applied in the pixel column direction (see FIGS. 45 and 46). 68, as in FIG. 67, the difference in the magnitude of the precharge voltage Vprc is indicated by numerals 1 to 4. A plurality of precharge voltages Vprc are generated. One type of precharge voltage Vprc may be applied to successive pixel columns. Further, the precharge voltage Vprc may be applied randomly to the pixel row. Further, the intensity of the precharge voltage Vprc may be changed at a constant period (two-dimensionally and in the time axis direction). Needless to say, the items described in FIG. 67 can be applied to other operations, contents, or configurations.

(17-4) Fourth Operation Method As shown in FIG. 69, different precharge voltages Vprc may be applied to the pixel columns and the pixel rows in a matrix. Of course, one type of precharge voltage Vprc may be applied to successive pixel rows or pixel examples. The precharge voltage Vprc may be applied randomly to the pixel row or pixel column. Further, the intensity of the precharge voltage Vprc may be changed at a constant period (two-dimensionally and in the time axis direction). The items described with reference to FIG. 67 can be applied to other operations, contents, or configurations. The precharge voltage Vprc or the exposure time Tc may be set in units of pixels or in units of processing blocks 881.

(17-5) Fifth Operation Method FIG. 70 is an example in which the change level of the precharge voltage Vprc and / or the exposure time Tc is set to 2. In FIG. 70, the magnitude of the precharge voltage Vprc, the difference in exposure time Tc, or a combination thereof is indicated by numerals 1 and 2. 1 is applied to detect the magnitude (intensity) of external light. 2 is used for calibration.

(18) Function setting of processing block In FIG. 47 and FIG. 48, it is designated for each processing block 881 what function processing block is to function and whether to respond to input. For example, the designation is performed by the command shown in FIG.

  In FIG. 49, a processing block 881 or an address area as a section for performing correction processing is 6 bits. Therefore, 64 areas (n = 63) can be processed or specified. For example, the first of the processing blocks corresponds to address 0. The final processing block is n = 63.

  The data area is 2 bits. That is, four states can be specified. For example, 0 indicates that input is not possible, and 1 indicates that input is possible. 2 indicates that the number of on-pixels needs to be corrected. Reference numeral 3 denotes a calibration in progress. Data specification is performed sequentially. The address and data are transmitted from the microcomputer.

(19) Reduction of first adverse effect from backlight 146 When coordinates such as a finger 671 are detected and coordinates are input, light from the backlight 146 that illuminates the liquid crystal display panel is affected. Hereinafter, a method for reducing the influence of light from the backlight 146 will be described.

  First, light from the backlight 146 or external light may enter from the side surface of the panel 148 and have an adverse effect. The adverse effect occurs when light incident from the side surface is diffusely reflected in the panel 148 and incident on the photosensor 64.

  65 and 66 are explanatory diagrams of a configuration for reducing the influence of light from the side surface of the panel 148 or the display invalid area.

  In FIG. 65, the light shielding portion 1281 is formed on the side surface of the substrate 148, the display invalid area (the area where light effective for image display does not pass or transmit).

  In FIG. 65A, the light shielding unit 1281 is disposed on the substrate 148.

  In FIG. 65B, in addition to the side surface of the substrate 148, the light shielding portion 1281 is disposed in an ineffective region (including a region and a side surface where light effective for image display does not pass or transmit). The arrangement means that a light shielding unit 1281 is separately provided and arranged in the vicinity of the substrate 148. Therefore, the light shielding portion 1281 is not limited to the direct application or formation of the substrate 148.

  FIG. 66 shows a configuration in which the light shielding portion 1281 or the light shielding material is filled or arranged between the substrate 148 and the housing 543. The light shielding unit 1281 uses a resin such as epoxy or acrylic containing a light absorbing material such as a dye, pigment, or pigment. Further, a light scattering material such as titanium oxide may be contained. Further, the invalid area of the substrate 148 may be directly processed and formed. Further, the substrate 148 may be a colored substrate.

  The light shielding film (light shielding portion) 1281 may be formed by directly coloring the substrate. The light shielding includes both an operation or configuration for reflecting light and an operation or configuration for absorbing light. The light shielding unit 1281 applies a dye, a pigment, or the like to the substrate using a technique such as inkjet printing. Application and drying may be performed at a high temperature, and the surface may be coated with a resin such as a UV resin, or an inorganic material such as silicon oxide or nitrogen oxide.

  The light shielding unit 1281 is formed by a gravure printing technique, an offset printing technique, a semiconductor pattern forming technique in which a film is applied by a spinner and developed. As the material for the light shielding portion 1281, a material having a black or dark color or a complementary color relationship of light to be modulated may be used. Alternatively, the photosensor 64 may transmit light having a wavelength that is difficult to react, and shield, absorb, or reflect light having a wavelength that easily reacts. For example, the photosensor 64 is more sensitive in the short wavelength (blue) region. Therefore, the light shielding film 1281 is preferably made of a material that reflects or absorbs blue. In particular, a material that reflects or absorbs 50% or more in a wavelength band shorter than 450 nm or less is employed.

  In addition, the light shielding unit 1281 may be formed of a metal thin film such as chromium (Cr), or may be formed of a resin obtained by adding carbon or the like to an acrylic resin. In addition, it may be a black metal such as hexavalent chromium, a paint, a thin film or a thick film or member having fine irregularities formed on the surface, a light diffuser such as titanium oxide, aluminum oxide, magnesium oxide, opal glass. Further, even if it is not dark or black, it may be colored with a dye or pigment having a complementary color relationship with light in the blue region sensitive to the photosensor 64. Further, it may be a hologram or a diffraction grating.

(19) Reduction of second adverse effect from backlight 146 When coordinates such as a finger 671 are detected and coordinates are input, light from the backlight 146 that illuminates the liquid crystal display panel is affected. This is because the light from the backlight 146 illuminates an object such as the finger 671 and a difference (brightness / darkness) from the external light cannot be obtained. This embodiment solves this problem by adopting the following configuration.

(19-1) First Solution Input icons (numbers 1 to 9 as an example) are displayed in the display area 10 of the panel 148 in association with the processing block 881 (FIG. 50A). Calibration is performed when there is no object such as a finger 671 on the display screen 10. The calibration may be performed even when the input object touches the display area 10.

  When the object 671 is touched on the display area 10 (FIG. 50 (b)), coordinate detection is performed where the object 671 is touched. Whether or not there is a symmetrical object 671 on the screen 10 can be easily detected by changing the precharge voltage Vprc or the exposure time Tc. However, even if detection is possible, it is often difficult to determine whether the finger 671 is in the air or is in contact with the display screen 10.

  When the precharge voltage Vprc or the exposure time Tc is changed and the object 671 is detected, the backlight 146 is turned off as shown in FIG. Alternatively, the luminance of the backlight 146 is reduced as compared with the normal display. For example, if the illuminance of light emitted from the backlight 146 during normal display is 100 Lx, at least the illuminance of the backlight 146 is set to 50% or less (50 Lx or less). That is, the backlight 146 is controlled so as to be in the range of 0 to 50% than usual.

  Although the backlight 146 is turned off or dimmed, it may be performed when the coordinate position or position detection of the object 671 is performed. Therefore, normal lighting may be performed at times other than the operation. That is, you may make it blink. Further, the brightness at the time of lighting in the blinking state may be controlled to be higher than normal and to be normal brightness as a whole (when averaged).

(19-2) Second Solution When the backlight 146 is turned off or dimmed, the image display is black. Or it becomes a brightness reduction display. Therefore, the operation or display in FIG. 50C can be realized not only by turning off the backlight 146 but also by displaying the image in the display area 10 in black (dark display). That is, the image display in FIG. 50C is set to a display state different from that in FIG. In brief, the display luminance of FIG. 50C is lowered as compared with FIG. Reduce the brightness of the icon, or display it in black or dark. Synonymously means to reduce the transmittance of the liquid crystal display panel. The transmittance is 50% or less.

  Black display or dark color display may be performed on the photosensor 64. The photosensor 64 is made of low-temperature polysilicon, and the photosensor 64 is configured by diode-connecting transistors. Therefore, the sensitivity is high at a short wavelength (close to blue). Therefore, in FIG. 50C, it is preferable to display an image such as an icon with a long wavelength color component (green or red). Note that it is not necessary to display all with long wavelength color components such as red display. As long as it is close to the color component of the long wavelength as a whole. When the sensitivity when the photosensor 64 displays 450 nm uniformly in blue is 100%, image display (icons, etc.) with a sensitivity of at least 50% or less is performed.

  For example, as shown in FIG. 52A, the input state (processing block 881) can be displayed in black, or can be controlled or adjusted by displaying a long wavelength or a short wavelength monochromatic display. Also, as shown in FIG. 52 (b), a process block 881 (a, d, h, i) that can be input is distinguished from a process block 881 (b, c, f, g) that is impossible or difficult to input. can do.

  FIG. 50D shows a state in which the normal icon display state is restored. In FIG. 50D, calibration or the like is performed at predetermined time intervals.

  Note that even a photosensor including a transistor formed or manufactured using high-temperature polysilicon or amorphous silicon has a high sensitivity region in a short wavelength region. Therefore, in FIG. 50C, when the image display is a shadow detection, it is preferable to display an image with a long wavelength (red). In the case of reflected light detection, it is preferable to display an image with a short wavelength (blue).

  In the above embodiment, the image display brightness of the display screen 10 is reduced. That is, although the transmittance of the liquid crystal display panel is reduced (the display color is changed to the long wavelength side), it may be controlled when the coordinate position or position detection of the object 671 is performed. Therefore, normal display may be performed at times other than the operation. That is, a blinking state (the detection operation of the object 671 is performed when the transmittance is reduced, and the normal display is performed in other cases). Alternatively, the transmittance (illuminance) at the time of lighting in the blinking state may be controlled to be higher than normal and to be the normal display (illuminance) as a whole (when averaged).

  For ease of explanation, the object 671 is detected by changing the precharge voltage Vprc, the exposure time Tc, and the like. However, when proper calibration is performed, the changing operation is not necessary. That is, there is no need to perform the operation of FIG. Of course, you may implement the operation | movement of FIG.50 (c). This is because more reliable coordinate detection or position detection is performed.

(19-3) Third Solution As shown in FIG. 51, the force sensor 712 may implement that the object 671 is in contact with the display screen 10. 51B and 51C show that the object 671 is in contact with the flat display device and the force sensor 712 is pressed. 51A and 51D show that the object 671 is not in contact with the flat display device.

  In FIG. 51A, input icons (numbers 1 to 9 as an example) are displayed in the display area 10 of the panel 148 in association with the processing block 881 (FIG. 51A). When the object 671 contacts in FIG. 51B, the force sensor 712 detects the contact. When detected, calibration is performed and the coordinate position is optimally detected.

  When the object 671 is touched on the display area 10 (FIG. 51 (b)), coordinate detection is performed where the object 671 is touched. Whether or not there is a symmetrical object 671 on the screen 10 can be easily detected by changing the precharge voltage Vprc or the exposure time Tc.

  When the precharge voltage Vprc or the exposure time Tc is changed and the object 671 is detected, the backlight 146 is turned off as shown in FIG. Alternatively, the luminance of the backlight 146 is reduced as compared with the normal display. For example, if the illuminance of light emitted from the backlight 146 during normal display is 100 Lx, at least the illuminance of the backlight 146 is set to 50% or less (50 Lx or less). That is, the backlight 146 is controlled so as to be in the range of 0 to 50% than usual.

  When the backlight 146 is extinguished or dimmed, the image display is black (or the luminance is reduced). Therefore, the operation or display in FIG. 51C can be realized not only by turning off the backlight 146 but also by displaying the image in the display area 10 in black display (dark display). That is, the image display in FIG. 51C is set to a display state different from that in FIG. The above items are the same as those in FIG. Further, since other items are also described with reference to FIG.

  The coordinate detection is not performed only when the flat display device is touched. The coordinate position may be detected even when the object 671 is in the air. For example, the center coordinate value of the object 671 is detected even when an object such as the finger 671 does not touch the display screen 10 and is in the air.

(20) Display of detection position The detected coordinate position is displayed on the display screen 10 by a cross cursor display as an example. When the object such as the finger 671 is moved in the air (a state in which the display screen 10 or the flat display device is not touched), the cross cursor moves along with the movement. Therefore, an input part can be shown visually to an input person. Calibration can be performed with or without a cross cursor. For example, it is assumed that calibration is not appropriate when a cross cursor or the like is not displayed. If one cross cursor is displayed without shaking, it is assumed that calibration is appropriate.

  Instead of the cross cursor, a heart mark or an animated character may be displayed. It is also preferable to change the character display according to the moving speed of the finger 671 or the like. When the object 671 comes into contact with the display screen 10, the character display is changed.

  In a touch panel that detects a resistance value, the position of the target cannot be detected unless the target touches the touch panel. In this embodiment, by detecting the shadow of the object 671, it is possible to detect the position of the shadow and display an image (a cross cursor, a character, etc.). This is a feature of this embodiment. In addition, the display state can be changed in two states, that is, contact detection of the object 671 and an air input state.

[Example of change]
The present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist thereof.

  For example, the present invention can be applied not only to a liquid crystal display device but also to a self-luminous display device including organic EL elements and inorganic EL elements. It can also be applied to other displays such as SED (trademark), PDP (plasma display panel), liquid crystal display device, display using carbon nano tube (CNT), cathode ray tube (CRT). . Further, the present invention can be applied not only to the active block display panel but also to a simple block display panel.

  The present invention can be applied to electrical appliances such as refrigerators and rice cookers, mobile phones, video cameras, projectors, stereoscopic televisions, projection televisions, cash drawers, watch finders, viewfinders, main monitors, sub-monitors, and clock displays. .

  The present invention can also be applied to scanners, image sensors, electrophotographic systems, head mounted displays, direct-view monitor displays, notebook personal computers, video cameras, digital still cameras, and electronic still cameras.

1 is a block diagram of a flat display device according to an embodiment of the present invention. It is the expansion explanatory drawing of a pixel similarly. It is a figure which similarly shows arrangement | positioning of a photo sensor pixel. It is a figure which similarly shows other arrangement | positioning of a photo sensor pixel. It is a figure which similarly shows other arrangement | positioning of a photo sensor pixel. It is the equivalent circuit schematic of a pixel similarly. It is the equivalent circuit schematic of a photo sensor pixel similarly. It is also a block diagram including peripheral circuits. It is a graph which shows the relationship between exposure time and external light. 3 is a timing chart of the display panel driving method. It is a figure which shows the relationship between a precharge voltage and time. It is explanatory drawing of the drive method of a display panel similarly. It is an explanatory diagram of a display panel provided with an enable signal line. It is explanatory drawing of a matrix process. It is explanatory drawing of the image capturing method. It is operation | movement explanatory drawing of a flat display apparatus similarly. It is explanatory drawing of the connection state of a photo sensor pixel and another comparator circuit. It is operation | movement explanatory drawing of a display panel similarly. It is explanatory drawing of the data acquisition method of a display panel similarly. It is explanatory drawing of the data acquisition method of a display panel similarly. It is a longitudinal cross-sectional view of a liquid crystal display device. It is a longitudinal cross-sectional view of the liquid crystal display device at the time of finger input. It is a longitudinal cross-sectional view of the liquid crystal display device at the time of finger input. It is a longitudinal cross-sectional view of the liquid crystal display device at the time of optical pen input. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the drive method of the display panel of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is a block diagram of the flat display apparatus of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment. It is explanatory drawing of the image capture method of the display panel of one Embodiment.

Explanation of symbols

10 Display area 11 Array substrate 12 Gate driver circuit 14 Source driver circuit
15 Signal processing circuit 16 Pixel 17 Circuit board 18 Photo sensor processing circuit 19 Display area (+ photo sensor formation area)
20 Flexible substrate 21 Video signal processing circuit 22 Gate signal line 23 Source signal line 24 Precharge voltage signal line 25 Photosensor output signal line 26 Display pixel 27 Photosensor pixel 31 Common signal line 32 TFT
34 Liquid crystal capacitor 35 Auxiliary capacitor 36 Counter electrode 61 Pixel electrode 62a First TFT
62b 2nd TFT
62c 3rd TFT
63 Capacitor 64 Photo sensor

Claims (13)

A plurality of signal lines and a first gate signal line arranged orthogonally to each other on the array substrate;
A display pixel including a display switching element provided near the intersection of the signal line and the first gate signal line, and a pixel electrode connected to the display switching element;
Display control means for supplying a video signal to the signal line and displaying a video by supplying a gate signal to the first gate signal line;
In a flat display device having
A plurality of photosensor pixels are provided in a matrix on the array substrate,
Photosensor processing means for reading a photosensor signal from each photosensor pixel is provided,
The photosensor pixel is
A first switching element that is turned on / off by a second gate signal from a second gate signal line disposed in parallel with the first gate signal line;
A capacitor for storing a charge by applying a predetermined precharge voltage from a precharge voltage supply line arranged in parallel with the signal line when the first switching element is on;
A photosensor that discharges the electric charge accumulated by the capacitor by changing the amount of light leakage according to the intensity of light;
A second switching element that is turned on / off based on a discharge voltage from the capacitor;
A third switching element for turning on / off between the second switching element and the photosensor signal output line by a third gate signal from a third gate signal line arranged in parallel with the first gate signal line;
Have
A plurality of photosensor pixels arranged in a matrix form one processing block,
A plurality of the blocks are provided on the array substrate,
The photo sensor processing means includes:
(1) When the precharge voltage is applied from the precharge voltage supply line, and the third switching element is in an on state, the photosensor signal output line changes depending on the on / off state of the second switching element. Read the potential as a photosensor signal,
(2) Counting the number of the photosensors that are on or off for each processing block, and determining whether the photosensors in the processing block are on or off based on the counted number. A flat display device. The flat display device according to claim 1, wherein the number of photosensor pixels constituting the one processing block is decreased as the external light intensity is weaker. The flat display device according to claim 1, wherein the resolution is increased by increasing the number of photosensor pixels constituting the one processing block when performing light pen input compared with performing finger input. In the display area on the array substrate, the number of photosensor pixels included in the processing block in the peripheral part of the display area is made larger than the number of photosensor pixels included in the processing block in the center part of the display area. The flat display device according to claim 1. The flat display device according to claim 1, wherein the photosensor processing unit determines whether the counted number is on / off based on an on determination number or an off determination number. The flat display device according to claim 5, wherein the photosensor processing unit sets the number of ON determinations to be smaller or the number of OFF determinations to be larger as the external light intensity is higher. 2. The flat display device according to claim 1, wherein among the photosensor pixels constituting the processing block, a photosensor pixel located at a central portion is set as a detection pixel, and neighboring photosensor pixels are set as non-detection pixels. The flat display device according to claim 1, wherein among the photosensor pixels constituting the processing block, a photosensor pixel that reacts to light and a photosensor pixel that does not react to light are mixed. The flat display device according to claim 1, wherein the processing block is long in a horizontal direction. The flat display device according to claim 1, wherein the processing block is long in a vertical direction. The photosensor processing means performs calibration so that the number of the photosensors in an on state or an off state is close to a target value by changing and applying the precharge voltage. 1. A flat display device according to 1. The flat display device according to claim 11, wherein the photosensor processing means applies the precharge voltage by a Newton method. The flat display device according to claim 11, wherein the photosensor processing means slows the change rate of the precharge voltage as it approaches the target value.

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