JP2005328352A - Input-sensor incorporated display device and driving method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a detection result from being influenced by variation in characteristics among amplifiers which extracts optical sensor outputs. <P>SOLUTION: In the input-sensor incorporated display device having sensor circuits and pixel circuits arranged two-dimensionally, the sensor circuits apply 5 V to signal lines Sib(n)R and 0 V to 2nd and 3rd signal lines Sib(n)G and Sib(n)B in the precharge period of a capacitor Cp to obtain a state in which a transistor nt1 is turned ON and an input/output transistor nt3 is turned ON. In a subsequent variation cancel period, a state in which the nt1 is turned ON and the nt3 is turned OFF is obtained and the terminal voltage across the capacitor Cp is set to Vth of the nt3. A state in which the nt1 is turned OFF and the nt3 is turned OFF is obtained in an imaging period. In a reading period, 5 V is applied to the 1st signal line, 0 V is applied to the 2nd signal line, and 0.5 V is applied to the 3rd signal line to turn the nt1 OFF and the nt3 ON, thereby detecting potential variation of the 1st signal line. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flat panel display device using a liquid crystal, a light emitting element, and the like, and more particularly to a driving method of a display device incorporating an input sensor.

  The liquid crystal display device includes an array substrate on which signal lines, scanning lines, and pixel TFTs are arranged, and a drive circuit that drives the signal lines and the scanning lines. With the recent progress and development of integrated circuit technology, a process technology for forming a part of a drive circuit on an array substrate has been put into practical use. As a result, the entire liquid crystal display device can be made light and thin, and it is widely used as a display device for various portable devices such as mobile phones and notebook computers.

  By the way, a display device having an image capturing function in which a contact area sensor (photoelectric conversion element) for capturing an image is arranged on an array substrate has been proposed (for example, see Patent Documents 1 and 2).

  A conventional display device having this type of image capturing function detects the voltage across the capacitor by changing the charge amount of the capacitor connected to the photoelectric conversion element according to the amount of light received by the photoelectric conversion element. The image is captured.

Recently, a technology for forming a pixel TFT and a driving circuit on the same glass substrate by a polycrystalline silicon (polysilicon) process has progressed, and the photoelectric conversion element described above is also formed by a polysilicon process. Can be easily formed.
Japanese Patent Laid-Open No. 2001-292276 JP 2001-339640 A

  When a display element and a photoelectric conversion element (photosensor) are built in a pixel of a display device, a display data processing device for driving the display device and a read data processing device for processing data read from the photoelectric conversion device are required. It is. Furthermore, when the content indicated by the image displayed on the display element is related to the content (timing, coordinate position, etc.) of the read data, a related data processing device for processing the correlation is necessary. Moreover, since the content of the read data changes based on the user's operation, it is important that the related data processing apparatus has flexibility.

  Here, a low-temperature polysilicon thin film transistor (Poly-Si-TFT) is used for the above-described optical sensor. When the output of this optical sensor is taken out, it is usually taken out through an amplifier because the current that responds to light is small. However, in the case of a display device, since the TFT amplifier is formed on the glass substrate, the variation in characteristics (or detection capability) between the amplifiers is larger than when the TFT amplifier is formed on a semiconductor wafer. Thus, if the variation in the characteristics between the amplifiers is large, the reliability of the detection result is low, the detection result is erroneously recognized, and the reliability of the product is lowered.

  Therefore, the present invention has been made in view of the above points, and in particular, the detection result can be prevented from becoming unstable due to variations in characteristics between amplifiers for taking out optical sensor outputs, and stable reading can be obtained. In addition, it is an object of the present invention to provide a driving method of a display device with a built-in input sensor that realizes this function without effectively increasing the number of components by effectively using a signal line for inputting a display signal.

  In order to achieve the above object, according to one aspect of the present invention, an amplifier (amplifier or amplification element) that amplifies a sensor signal in a pixel, a sensor connected to an input of the amplifier, and an input voltage of the amplifier The basic configuration includes means for setting the operation threshold of the amplifier and means for shifting the input voltage of the amplifier by a predetermined value before the amplifier outputs a signal.

  According to another aspect of the present invention, there is provided a sensor unit in which a capacitor and a photodiode form a parallel circuit, an amplification transistor in which one electrode of the sensor unit is connected to a gate, one electrode of the amplification transistor, and the electrode A variation canceling transistor connected in series between one electrode of the sensor unit, an input / output transistor having one electrode connected to one electrode of the amplification transistor, and a second electrode connected to the other electrode of the input / output transistor Control of the first signal line, the second signal line connected to the other electrode of the amplifying transistor, the third signal line connected to the other electrode of the sensor section, and the variation canceling transistor A first gate line connected to the control gate, a second gate line connected to the control gate of the input / output transistor, and the capacitor In the charging period, a first predetermined potential is applied to the first signal line, a 0 potential is applied to the second and third signal lines, and the variation cancel transistor is turned on via the first gate line. Means for obtaining a state in which the input / output transistor is turned on via the second gate line, and the variation canceling transistor is turned on via the first gate line during the variation canceling period following the precharge period. Means for obtaining a state in which the input / output transistor is turned off via the second gate line, and the variation canceling transistor is turned off via the first gate line during the imaging period. Means for obtaining a state in which the input / output transistor is turned off, and applying the first predetermined potential to the first signal line in a reading period; 2 potential is applied to the second signal line, and the third signal line is applied with a potential approximately half of the preset maximum change range of the sensor unit, and the variation canceling transistor is provided via the first gate line. And means for obtaining a state in which the input / output transistor is turned on via the second gate line.

  By the above means, the initial potential of the capacitor is initially set equal to the threshold value Vth of the amplification transistor in the variation canceling period. Accordingly, whether or not the potential across the capacitor has changed due to light detection can be determined by whether the potential of the capacitor substantially maintains the threshold value Vth or lowers than that. The detection based on this determination is performed during the reading period, and is performed depending on whether or not the predetermined potential of the first signal line changes depending on whether the amplification transistor maintains an off state or turns on.

  Embodiments of the present invention will be described below with reference to the drawings. First, an overall schematic configuration of a display device with a built-in input sensor according to an embodiment of the present invention will be described with reference to FIG.

  Reference numeral 100 denotes a display and sensor unit. For example, the display and sensor unit uses liquid crystal. The display and sensor unit 100 includes display elements that are two-dimensionally arranged in a matrix and sensing elements that are two-dimensionally arranged in a matrix. This structure will be described in detail later.

  Reference numeral 200 denotes a system control unit for controlling each part of the display device with a built-in input sensor, or a system control unit (computer device) prepared independently outside, and shows a part related to the present invention. . The system control unit 200 is built on the main board. The system control unit 200 includes a microcomputer 201, the microcomputer 201, and various control units 202 for realizing various control operations based on application programs. Basic programs are stored in the ROM 203, and various application programs are stored in the RAM 204. The timer 205 generates reference time information for this apparatus. Reference numeral 206 denotes an external control interface and a data interface, which input / output control data (command input / output) and image data. It can also be connected to external devices, set-top boxes, tuners, modems, personal computers, and the like.

  Reference numeral 300 denotes a display and imaging data processing unit, which realizes the previous display and display state of the sensor unit 100, the imaging state, the display and imaging timing, the region setting, and the like in response to a command from the system control unit 200. The display and imaging data processing unit 300 includes a write / read only processing unit 312, and can temporarily store captured image data, image data for display, and the like in a memory (SRAM) 311. Furthermore, it has a switch and LED processing unit 313, which can process an external switch input (for example, an operation signal for sensitivity adjustment, brightness adjustment, etc.), and further inform the system status to the outside. A light emitting element (LED) can also be driven. The write / read only processor 312 includes a read signal processor and a write signal processor. The read signal processing unit can convert the detection signal from the display and sensor unit 100 into various states based on the application. The write signal processing unit performs processing for displaying a signal for display and sending it to the sensor unit 100.

  The write / read only processing unit 312 is connected to the previous display and sensor unit 100 via the relay board 400. The relay board 400 is equipped with a power supply circuit, a digital-analog converter that converts image data for display, and the like.

  The types of signals given to the display and sensor unit 100 are roughly classified into display control signals, display RGB image data, and imaging control signals. Moreover, there is imaging data as a signal read from the display and sensor unit 100.

  FIG. 2 shows basic functional blocks of the display and imaging data processing unit 300, particularly the write / read only processing unit 312. A digital interface 302 is connected to the interface 206 of the system control unit 200, the switch, and the LED processing unit 313. The data taken into the interface 302 is recognized by the data separation and data transfer unit 303. Commands sent from the outside are stored in the command register 304.

  The imaging condition / imaging form lookup table 305 stores information on a plurality of imaging conditions (precharge voltage, imaging time, etc.), and these information can be written from the system control unit 200 via an interface. It can also be read from the system control unit 200 side. In addition, the timing signal generated in the write / read timing control unit and the data input / output unit 306 is monitored, and the phase of the timing signal output from the write / read timing control unit and the data input / output unit 306 is controlled. Is also possible.

  The writing / reading timing control unit and data input / output unit 306 also outputs an imaging control signal and a display control signal based on the control data from the imaging condition / imaging form lookup table 305. Further, in response to a command from the command register 304, the imaging data can be output to the outside via the data separation and data transfer unit 303. Further, in order to store the imaging data in the SRAM 311, it can be transferred to the SRAM control unit 307. Furthermore, the image data for display can be received and sent to the display and sensor unit 100. When the data stored in the SRAM 311 is used as display image data, the image data is sent to the write / read timing control unit and the data input / output unit 306 via the SRAM control unit 307. When image data from the outside is used as image data for display, this image data is sent to the write / read timing control unit and data input / output unit 306 via the data separation and data transfer unit 303.

  The SRAM control unit 307 performs control to store the imaging data captured via the write / read timing control unit 306 in the SRAM 311. In addition, the image data stored in the SRAM 311 is controlled to be displayed and sent to the sensor unit 100 via the write / read timing control unit 306. Furthermore, editing processing of image data stored in the SRAM 311, image switching processing, and the like can be performed in accordance with commands. Further, the image data from the SRAM 311 can be sent to the outside via the data separation and data transfer unit 303 and the interface 302.

  In addition, the SRAM control unit 307 can store image data, control data, and the like sent from the outside via the interface 302 and the data separation and data transfer unit 303 in the SRAM 311. Further, it is possible to calculate the coordinates at which the user points on the display surface using the imaging data and determine whether or not the user has tapped.

  The command register 304 stores commands. The following processing is executed according to the command. A reset process can be performed. In mode designation 1, it is possible to switch between the normal display mode and the input enable mode. The input enable mode is to read and process image data from the display and sensor unit 100 and set it to a state for processing. In the case of only normal display, power consumption can be saved by not outputting imaging data from the display and sensor unit 100.

  In mode designation 2, it is possible to switch between the main imaging state and the calibration imaging state. In the calibration imaging state, by closing (turning off) the display element unit in the display and sensor unit 100, it is possible to concentrate on imaging and acquire data for reducing imaging unevenness.

  The phase signal of the video signal with respect to the reference signal is passed to the writing / reading timing control unit and data input / output unit 306 to cause the display and sensor unit 100 to execute signal processing at an optimal timing. Further, when image data for two screens is stored in the SRAM 311, the display is instantaneously switched. The transfer mode (handshake (HS) / burst) is switched, that is, the imaging condition / imaging form lookup table 305 and the SRAM control unit 307 transfer data of a predetermined unit to the data separation and data transfer unit 303 and the interface 302. If so, set the transfer method, transfer speed, etc. A sampling timing is instructed, that is, the display and sensor unit 100 is instructed to sample the imaging data output from the display and sensor unit 100. A write permission command is issued from the system control unit 200 side, that is, data writing is permitted to the imaging condition / imaging form lookup table 305 and the SRAM control unit 307 via the interface 302.

  The interface 302 receives a command from the system control unit 200 side and performs a writing process to the command register 304. Also, data for setting the imaging condition / imaging form is received from the system control unit 200 side and sent to the imaging condition / imaging form lookup table 305. In addition, image data to be written to the SRAM 311 is received from the system control unit 200 side and sent to the SRAM control unit 307. Also, calculation results such as coordinates and tap information are received from the SRAM control unit 307 and sent to the system control unit 200 side.

  As the transfer mode, there is a handshake (HS) (up to 1.5 Kbps), and writing to the command register 304 and writing of data to the imaging condition / imaging form lookup table 305 are performed at this speed. The transfer mode includes burst transfer (up to 160 Mbps), in which data reading from the imaging condition / imaging form lookup table 305 and data reading / writing to the SRAM 311 are performed. These transfer modes are selectively used.

  The display and imaging data processing unit 300 receives various applications stored in the various control units 202 of the system control unit 200 and commands from the system control unit 200 generated based on the various applications. Therefore, according to the application, the apparatus of the present invention can be used in various ways and usage forms. The display and imaging data processing unit 300, the system control unit 200, and the display and sensor unit 100 may be configured integrally. Alternatively, the display and imaging data processing unit 300 and the display and sensor unit 100 may be integrated, and the system control unit 200 may be independent.

  Therefore, in the present invention, various types of the digital interface 302 in the display and imaging data processing unit 300 may be prepared. That is, a USB may be used for connection to the outside, and a wireless modem unit or the like may be prepared. Further, it may be connectable to a data input / output unit of a mobile phone. Furthermore, an RGB terminal, a YIQ terminal, and the like may be provided for video signals.

  FIG. 3 shows the functions of the display and sensor unit 100 in blocks. Reference numeral 130 denotes a pixel and sensor array unit, which includes display element groups arranged in a matrix and photosensor groups arranged in a matrix. The pixel circuit and sensor circuit of the pixel and sensor array unit 130 will be described later.

  A display gate line driving circuit 112 and a reading gate line driving circuit 122 are formed on the side (left side in the drawing) of the pixel and sensor array unit 130. The display gate line driving circuit 112 is a circuit that drives a display element group arranged in a matrix for each row or a plurality of rows.

  Here, the read gate line driving circuit 122 is a circuit that drives the photosensor groups arranged in a matrix in units of rows or in units of a plurality of rows.

  A signal line driving circuit and a precharge circuit 114 are formed on the lower side of the pixel and sensor array unit 130. The signal line driving circuit and precharge circuit 114 is a circuit for writing image data to each display element in the column direction of a display element group arranged in a matrix. The signal line drive circuit and precharge circuit 114 is a circuit that precharges a predetermined potential to each sensor in the column direction of the photosensor group arranged in a matrix.

  An A / D conversion circuit 123 and a data output circuit 124 are formed above the pixel and sensor array unit 130. The A / D conversion circuit 123 is a circuit that performs analog-digital conversion on a signal read from the signal line of the optical sensor group and transfers the signal to the data output circuit 124. The data output circuit 124 converts the captured data into serial data, and then outputs it as imaging data 125.

  Here, the readout gate line driving circuit 122 is provided with the imaging control signal 121 from the previous display and imaging data processing unit 300 via the relay board 400. The display gate line driving circuit 112 is provided with a display control signal 111 from the previous display and imaging data processing unit 300 via the relay board 400. Further, R, G, B image data is given to the signal line driver circuit and precharge circuit 114 from the previous display and imaging data processing unit 300 via the relay board 400. The R, G, B image data is converted into an analog voltage suitable for gradation display of a liquid crystal cell by a digital-analog conversion circuit (DAC) on the relay board, and is converted to a predetermined signal line via a signal line driving circuit. The data is written and further written to the pixels in the row designated by the display gate line driving circuit 121. Further, a precharge voltage control signal 115 may be provided. The gradation display of the liquid crystal cell may be a frame rate control method.

  The pixel and sensor (also referred to as read / write pixel) portion includes a display pixel circuit 1311 and a reading sensor circuit 1312.

  FIG. 4 shows a basic circuit configuration example of the read / write pixel. Cs is a voltage line that applies a predetermined potential to the one electrode of the auxiliary capacitor Csk and the liquid crystal LC at a predetermined cycle. Gate (m) is a gate line for controlling on / off of a thin film transistor (TFT) (hereinafter referred to as a drive transistor) 13a of the pixel circuit 1311.

  Here, the pixel circuit 1311 is shown as a circuit capable of color display. That is, the pixel circuits 132R, 132G, and 132B are shown. Sig (n) R, Sig (n) G, and Sig (n) B are signal lines and are formed at respective horizontal positions. The signal lines Sig (n) R, Sig (n) G, and Sig (n) B are connected between the signal line driving circuit / precharge circuit 114 and the A / D conversion circuit 123. The image data R, G, and B for display are supplied to the corresponding signal line via the signal line drive circuit / precharge circuit 114 as shown in FIG. Then, when the gate line Gate (m) at the position where the image data R, G, B is to be displayed is turned on, the image data R, G, B corresponding to the corresponding auxiliary capacitance Csk is written, and the liquid crystal LC is Driven.

  CRT (m) is a gate line for on / off control of the thin film transistor nt1 constituting the sensor circuit 1312 (in the present invention, this transistor functions as a variation canceling transistor). OPT (m) is a gate line for on / off control of the thin film transistor nt3 constituting the sensor circuit 1312 (in the present invention, this transistor functions as an input / output transistor).

  The voltage line CS and the gate line Gate (m) are connected to the display gate line driving circuit 112, and the gate line CRT (m) is connected to the reading gate line driving circuit 122.

  Here, reference numeral 133 denotes a sensor unit that forms the sensor circuit 1312, and the capacitor Cp and the photodiode PD form a parallel circuit. One electrode of the sensor unit 133 is connected to the gate of the thin film transistor nt2 (in the present invention, this transistor functions as an amplification transistor). The other electrode of the sensor unit 133 is connected to, for example, the signal line Sig (n) B.

  The variation canceling transistor nt1 is connected in series between one electrode of the amplification transistor nt2 and one electrode of the sensor unit 133. In addition, one electrode of the input / output transistor nt3 is connected to one electrode of the amplification transistor nt2. Here, the other electrode of the input / output transistor nt3 is connected to the first signal line Sig (n) R. The other electrode of the amplifying transistor nt2 is connected to the second signal line Sig (n) G. The other electrode of the sensor unit 133 is connected to the third signal line Sig (n) B. When the amount of light irradiated to the photodiode PD is large, the discharge amount of the sensor capacitor Cp is large. Conversely, when the amount of light irradiated to the photodiode PD is small, the discharge amount of the sensor capacitor Cp is small. A light shielding process is performed between the photodiode PD and a backlight (not shown).

  A signal line driving circuit / precharge circuit 114 is connected to the signal lines Sig (n) R, Sig (n) G, and Sig (n) B. The voltage setting circuit 1140 is included in or related to, and the potential of the signal lines Sig (n) R, Sig (n) G, and Sig (n) B can be switched. Furthermore, the potential switching timing can be obtained in accordance with the sequence control signal from the sequencer 1141. The sequence signal from the sequencer 1141 is obtained based on the control signal from the previous display and imaging data processing unit 300.

  FIG. 5 is a timing chart showing operations of the pixel circuit 1311 and the sensor circuit 1312 described above.

  The writing of the image data to the pixel circuits 132R, 132G, and 132B and the reading of the imaging signal from the sensor circuit 1312 are performed in a specific horizontal period in one frame period. In a pixel circuit (or a display element circuit) 1311, one horizontal period (1H) is divided into a first blank period, a common inversion timing period, an address period, and a second blanking period. In correspondence with these four periods, the sensor circuit 1312 is divided into an output period, a common inversion timing period, a blank period, a precharge and a variation cancel period. In other periods excluding the specific period within one vertical period (one frame period), the pixel circuit 1311 is in the display period, and the sensor circuit 1312 is in the imaging period.

  Further, the operation of the sensor circuit 1312 will be described in detail. In the precharge period of the capacitor Cp, a first predetermined potential (for example, 5 V) is applied to the first signal line Sig (n) R, and the second and third signal lines Sig (n) G, Sig (n) A zero potential is applied to B. At the same time or subsequently, the variation cancel transistor nt1 is turned on via the first gate line CRT (m) and the input / output transistor nt3 is turned on via the second gate line OPT. Next, in the variation cancel period following the precharge period, the variation cancel transistor nt1 is turned on through the first gate line CRT (m), and the input / output transistor nt3 is turned off through the second gate line OPT (m). To the state. Then, in this variation canceling period, the initial potential of the capacitor Cp is initially set equal to the threshold value Vth of the amplification transistor. That is, when the potential immediately after the charging of the capacitor Cp is high, the transistor nt2 is turned on and discharged, and just stops at the threshold value Vth of the transistor nt2. In the variation cancel period, the initial potential of the capacitor is initially set equal to the threshold value Vth of the amplification transistor.

  In this state, in the next imaging period, the variation cancellation transistor nt1 is turned off via the first gate line CRT (m), and the input / output transistor nt3 is turned off via the second gate line OPT (m). . In this state (imaging period = [(1 frame period) − (1 horizontal period (specific horizontal period))]), for example, when the photodiode PD is irradiated with light reflected by the touched finger, the sensor Discharge of the capacitor Cp proceeds. Conversely, when the photodiode PD is not irradiated with light, the discharge of the sensor capacitor Cp does not proceed.

  In the reading period, the first predetermined potential (5 V) is sampled on the first signal line Sig (n) R, the zero potential is applied to the second signal line Sig (n) G, and the third signal line Sig ( n) The potential of B is approximately ½ of the preset maximum change range of the sensor unit 133 (for example, 0.5 V. It may be adjusted by TFT characteristics or parasitic capacitance. It is smaller than the maximum change range of the sensor unit 133. .)give. Further, the variation cancel transistor nt1 is turned off via the first gate line CRT (m), and the input / output transistor nt3 is turned on via the second gate line OPT (m). Here, “sampling” means that the signal line is connected to the 5V power supply line to set the signal line potential to 5V and then further electrically separated from the 5V power supply line.

  Now, it is assumed that the potential (5 V) of the capacitor Cp is decreased by 1 V during the imaging period. Then, in the reading period, the gate potential of the amplification transistor nt2 is (Vth−0.5V). This is because 0.5 V is applied to the third signal line Sig (n) B, and therefore, (−1) + 0.5 = −0.5 V with respect to Vth. If the discharge of the capacitor Cp has not progressed, the gate potential of the amplification transistor nt2 becomes (Vth + 0.5V).

  Therefore, the above-mentioned 0.5V is applied to the third signal line Sig (n) B, the first predetermined potential (5V) is applied (sampled) to the first signal line Sig (n) R, and the first When a potential of 0 is applied to the second signal line Sig (n) G, the transistor nt2 is turned on if the discharge of the capacitor Cp is not progressing, and the transistor nt2 is kept off if the discharge of the capacitor Cp is proceeding. Will do. As a result, the voltage change of the signal line Sig (n) R is surely obtained depending on whether or not the capacitor Cp is discharged. That is, it is possible to reliably extract the output of the sensor circuit without being affected by variations in the characteristics of the transistor nt2.

  As described above, in the variation cancel period, the initial potential of the capacitor is initially set equal to the threshold value Vth of the amplification transistor. Accordingly, whether or not the potential across the capacitor has changed due to light detection can be determined by whether the potential of the capacitor substantially maintains the threshold value Vth or lowers than that. Detection based on this determination is performed during the reading period, and is performed depending on whether or not the predetermined potential of the first signal line changes depending on whether the amplification transistor is kept off or turned on.

  FIG. 6 is a flowchart showing a processing procedure by the sequencer 1141 prepared especially for driving the sensor circuit 1312 in order to obtain the above operation. The sequencer 1141 may be incorporated in the signal line driver circuit / precharge circuit 114 shown in FIG. 3, or may be provided in the timing controller 306 shown in FIG. In FIG. 6, steps SA1 to SA3 are the precharge and variation cancellation period described above. The next step SA4 is an imaging period. Further, the next steps SA5, SA6, and SA7 are the previous reading period. It is determined whether or not there is an input depending on whether or not the predetermined potential of the first signal line changes.

  FIG. 7 is an explanatory diagram showing the above operation in units of frames (the Nth frame and the (N + 1) th frame).

  Here, in the present invention, the image signal may be read out in a short time. Therefore, in the present invention, when reading the imaging signal, the charges of the sensor circuits for a plurality of rows are read simultaneously or successively.

  For example, in the present invention, the imaging signal is read out in units of sensor circuits (sensor circuit group) for 10 rows, for example. Hereinafter, the operation of the sensor circuit will be described.

  FIG. 8 is an explanatory diagram showing the above operation in units of frames (the Nth frame and the (N + 1) th frame). Although the contents are almost the same as those shown in FIG. 7, in this example, the reading unit is a unit of 10 rows. Therefore, to read the information of the sensor circuit group in one frame, a time (1/10) TPF which is one tenth of the time TPF for reading out one row at a time may be sufficient. For this reason, a time margin for processing the detection signal obtained from the sensor circuit is obtained. Having this time margin is important. This is because the information input via the sensor circuit group requires time necessary for making various logical judgments. As for the writing of the video signal, for example, a symbol image such as a numeric keypad or switch image is not realized by only one pixel. Therefore, paying attention to the fact that such a symbol image does not cause a problem even if writing processing is performed in units of a plurality of pixels, video signals are written to pixels of a plurality of rows. As a result, a time margin is also provided for the writing process. When a video signal is written, for example, video signals R, G, and G for 10 rows are time-divided during a video writing period (shown in FIG. 9B), and Sig (n) R, Sig (n) B, The data is output from the writing circuit (signal line driving circuit / precharge circuit 114) to Sig (n) G. The signal line driver circuit / precharge circuit 114 has a function of switching and setting the potential of the signal line to an appropriate potential in order to realize the above operation.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment. Although the above embodiment has been described with respect to the optical sensor, the same effect can be obtained by applying the present invention to a circuit that amplifies and outputs a signal from a sensor other than the optical sensor (such as a piezoelectric element or a capacitive sensor).

The block block diagram which shows one embodiment of this invention. The block diagram which shows the structure of the display and imaging data processing part of FIG. 1 in detail. 1 is an overall block configuration diagram of a display and sensor unit 100 according to the present invention. FIG. 4 is an explanatory diagram illustrating a specific example of a pixel circuit and a sensor circuit in FIG. 3. FIG. 4 is an explanatory diagram illustrating operation timings of the pixel circuit and the sensor circuit in FIG. 3. The flowchart of the control part for controlling the pixel circuit and sensor circuit of FIG. Explanatory drawing shown in order to demonstrate the display and imaging timing of the apparatus which concerns on this invention per frame. Explanatory drawing shown in order to demonstrate the other example of the display of the apparatus which concerns on this invention, and an imaging timing per frame.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Display and sensor part, 200 ... System control part, 300 ... Display and imaging data process part, 400 ... Relay board, 1311 ... Pixel circuit (display element circuit), 1312 ... Sensor circuit.

Claims (9)

  An amplifier for amplifying the signal of the sensor in the pixel; a sensor connected to the input of the amplifier; means for setting an input voltage of the amplifier to an operating threshold value of the amplifier; and before the amplifier outputs a signal, A display device with a built-in input sensor, comprising means for shifting the input voltage of the amplifier by a predetermined value.   2. The input sensor built-in display device according to claim 1, wherein the predetermined value is set smaller than a signal change width of the sensor. In the display device with a built-in input sensor in which a sensor circuit and a pixel circuit are two-dimensionally arranged, the sensor circuit includes:
A sensor unit in which a capacitor and a photodiode form a parallel circuit;
An amplification transistor in which one electrode of the sensor unit is connected to a gate;
A variation canceling transistor connected in series between one electrode of the amplification transistor and the one electrode of the sensor unit;
An input / output transistor having one electrode connected to one electrode of the amplification transistor;
A first signal line connected to the other electrode of the input / output transistor;
A second signal line connected to the other electrode of the amplifying transistor;
A third signal line connected to the other electrode of the sensor unit;
A first gate line connected to a control gate of the variation canceling transistor;
A second gate line connected to the control gate of the input / output transistor;
In the precharge period of the capacitor, a first predetermined potential is applied to the first signal line, a zero potential is applied to the second and third signal lines, and the variation is applied via the first gate line. Means for obtaining a state in which a cancel transistor is turned on and the input / output transistor is turned on via the second gate line;
Means for obtaining a state in which the variation canceling transistor is turned on via the first gate line and the input / output transistor is turned off via the second gate line during the variation canceling period following the precharge period;
Means for obtaining a state in which the variation canceling transistor is turned off via the first gate line and the input / output transistor is turned off via the second gate line during the imaging period;
During the readout period, the first predetermined potential is applied to the first signal line, the second signal line is set to 0 potential, and the third signal line is set to approximately the preset maximum change range of the sensor unit. Means for applying a potential of 1/2 and obtaining a state in which the variation canceling transistor is turned off via the first gate line and the input / output transistor is turned on via the second gate line;
A display device with a built-in input sensor.   4. The display device with a built-in input sensor according to claim 3, wherein means for reading a potential change of the first signal line is provided during the readout period.   The first, second, and third signal lines are display signal input signals connected to the corresponding red (R) pixel circuit, green (G) pixel circuit, and blue (B) pixel circuit. The display device with a built-in input sensor according to claim 3, wherein the display device is a line.   A signal line driver circuit for supplying a video signal to each of the first, second, and third signal lines is provided in a period between the readout period and the precharge period. Item 5. The display device with a built-in input sensor according to Item 4. In the driving method of a display device with a built-in input sensor in which a sensor circuit and a pixel circuit are two-dimensionally arranged, the sensor circuit includes a sensor unit in which a capacitor and a photodiode form a parallel circuit, and one electrode of the sensor unit includes An amplification transistor connected to the gate, a variation canceling transistor connected in series between one electrode of the amplification transistor and the one electrode of the sensor unit, and one electrode connected to one electrode of the amplification transistor An input / output transistor, a first signal line connected to the other electrode of the input / output transistor, a second signal line connected to the other electrode of the amplifying transistor, and the other of the sensor section A first signal line connected to a third signal line connected to the electrode and a control gate of the variation canceling transistor; A gate line and a second gate line connected to the control gate of the input transistor,
In the precharge period of the capacitor, a first predetermined potential is applied to the first signal line, a zero potential is applied to the second and third signal lines, and the variation is applied via the first gate line. A cancel transistor is turned on, and the input / output transistor is turned on via the second gate line;
In a variation cancel period following the precharge period, the variation cancel transistor is turned on via the first gate line, and the input / output transistor is turned off via the second gate line,
In the imaging period, the variation cancellation transistor is turned off through the first gate line, and the input / output transistor is turned off through the second gate line,
During the readout period, the first predetermined potential is applied to the first signal line, the second signal line is set to 0 potential, and the third signal line is set to approximately the preset maximum change range of the sensor unit. A half potential is applied, and the variation canceling transistor is turned off via the first gate line, and the input / output transistor is turned on via the second gate line.
A drive method for a display device with a built-in input sensor.   8. The method for driving a display device with a built-in input sensor according to claim 7, wherein a change in potential of the first signal line is read and determined as an output of a sensor circuit during the readout period.   8. The display device with a built-in input sensor according to claim 7, wherein video signals are respectively supplied to the first, second, and third signal lines in a period between the readout period and the precharge period. Driving method.

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