JP2008102418A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device having a sensor, with the device capable of obtaining information of light properly and securely, regardless of whether the illumination intensity of outside light is high or low. <P>SOLUTION: A plurality of pixel areas, including a plurality of light sensors 32, having arithmetically or geometrically different widths, and a plurality of light sensors 32 each having a width equal to the maximum of the arithmetically or geometrically different widths or larger than the maximum are disposed in a display unit 11 which is a display area. Hence, it is possible to adjust the light detection sensitivity of a pixel area (and a display area), as well, as to increase the light detection sensitivity in the pixel area (and the display area), and the display device can properly and securely obtain information of light, regardless of whether the illumination intensity of outside light is high or low. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technology of a display device provided with a sensor.

  A display device such as a liquid crystal display has a great advantage of being thin, lightweight, and low power consumption, and is widely used as a display for a personal computer, a mobile phone and the like. Further, by adding an input function such as a touch panel or a pen input to these display devices, the use is further expanded (see Patent Document 1).

  Such a display device includes a display unit and an imaging unit for each pixel, and in addition to a display function for displaying an image, a light receiving unit (for example, a photoelectric conversion element) included in the imaging unit in the pixel causes environmental light or By detecting external light such as backlight light, a recognition function for capturing an image of a recognition object such as a finger is realized.

Here, the light detection sensitivity of the imaging unit is proportional to the width of the light receiving unit. Moreover, since the light receiving unit is provided integrally with the display unit, the maximum width of the light receiving unit is limited by the size of the display unit. In addition, the minimum width of the light receiving portion is limited by the fine processing technology of the manufacturing process.
JP 2004-318819 A

  However, the imaging unit in the pixel is usually provided with only the aperture ratio taken into consideration without considering the light detection sensitivity of the light receiving unit. For this reason, many light-receiving parts with low light detection sensitivity may be installed, and there is a problem that the recognition performance (capture performance) is lowered in accordance with the increase or decrease in the illuminance of external light such as ambient light and backlight light.

  The present invention has been made in view of the above, and it is an object of the present invention to provide a display device that appropriately and reliably obtains optical information regardless of the intensity of external light illuminance.

  A display device according to a first aspect of the present invention includes a display region in which a plurality of pixel regions each having a plurality of pixels are arranged, a plurality of sensors having different widths that are provided in the pixel region in an equal or different ratio, And a plurality of sensors having a width equal to or greater than the maximum value of the width provided in the pixel region.

  In the present invention, it is possible to adjust the photodetection sensitivity of the pixel area (and display area) by a plurality of sensors having different widths that are either differentially or equiproportionally, and are also differentially or equally proportional. A plurality of sensors having a width equal to or larger than the maximum value of different widths can improve the light detection sensitivity of the pixel region (and the display region), so that the display device emits light regardless of the intensity of external light illuminance. Information can be obtained appropriately and reliably.

  In the display device according to the second aspect of the present invention, the number of sensors having a width equal to or greater than the maximum value of the differently or equally different widths may be the same or differently. The number of sensors having different widths is 1/3 or more.

  In the present invention, the number of sensors having a width that is equal to or greater than the maximum value of the differentially or equally different widths is different from that of the sensor having a differentially or equally different width. Since it is 1/3 or more of the quantity, the light detection sensitivity of the pixel region can be improved more reliably.

  A display device according to a third aspect of the present invention is equivalent to or larger than the maximum value of the plurality of sensors having different widths that are different in the same or different ratio, and the width that is different in the same or different ratio. A plurality of width sensors are randomly arranged in the pixel region.

  In the present invention, a plurality of sensors having different widths that are differentially or equally different, and a plurality of sensors having a width that is equal to or greater than the maximum value of differently or equally different widths. Since the pixels are randomly arranged in the pixel region, it is possible to suppress the influence of variations in sensor characteristics that occur during the manufacturing process, and to prevent periodic unevenness during image capture.

  The display device according to a fourth aspect of the present invention further includes a control circuit that adjusts an exposure time and / or a precharge voltage of the sensor in accordance with the external light illuminance captured by the sensor.

  The present invention further includes a control circuit that adjusts the exposure time and / or precharge voltage of the sensor in accordance with the external light illuminance captured by the sensor, thereby reliably preventing blackout or whiteout of the captured image. be able to.

  A display device according to a fifth aspect of the present invention is characterized in that a plurality of the pixels have the same transmittance.

  In the present invention, since the transmittance of a plurality of pixels is the same, it is possible to prevent deterioration in display quality such as luminance variation that occurs when a plurality of sensors having different widths are arranged.

  In a display device according to a sixth aspect of the present invention, the pixels include red, green, and blue sub-pixels, and the plurality of sensors having different widths that are the same or different from each other, and the equal differences. A plurality of sensors having a width equal to or greater than a maximum value of different widths that are different from each other is provided for at least one of the sub-pixels.

  The display device according to a seventh aspect of the present invention is characterized in that the red, green, and blue sub-pixels have the same transmittance.

  In the present invention, since the transmittances of the red, green, and blue sub-pixels are the same, it is possible to prevent the white balance of the display device from being lowered.

  In the display device according to an eighth aspect of the present invention, the control circuit uses at least a part of the sensor signal values from the plurality of sensors having different widths that are different from each other in the same or different ratio. The sensor exposure value and / or the precharge voltage of the sensor are adjusted by replacing with sensor signal values from a plurality of sensors having a width equal to or greater than the maximum value of different widths.

  In the present invention, at least a part of sensor signal values from a plurality of sensors having different widths that are differentially or equally different are equal to or the maximum of the maximum values of differently or equally different widths. Since the sensor signal values from a plurality of sensors having a width larger than the value are replaced, the object close to the display device can be more reliably recognized even when the external light illuminance is low.

  According to the present invention, optical information can be obtained appropriately and reliably regardless of the intensity of external light illuminance.

  Hereinafter, the present embodiment will be described with reference to the drawings.

<Description of overall configuration of display device>
FIG. 1 is a configuration diagram illustrating a schematic configuration of a display device 1 according to the present embodiment. The display device 1 includes an array substrate 2 formed of a light-transmitting substrate such as a glass substrate, and an external substrate 4 connected to the array substrate 2 via a flexible substrate 3.

  The array substrate 2 includes a display area 11 for displaying an image, a scanning line driving circuit 12 for outputting a scanning signal GATE to a scanning line G (n: positive integer), and a video on a signal line S (m: positive integer). A signal line drive circuit 13 for outputting a signal, a reset control line drive circuit 14 for outputting a reset control signal CRT to a reset control line C (n: positive integer), and an output control for an output control line O (n: positive integer) An output control line driving circuit 15 that outputs a signal OPT, a sensor output circuit 16 that outputs sensor output data to the external substrate 4, an interface circuit 17 for the external substrate 4, and the like are provided.

  The flexible substrate 3 is provided with a plurality of wirings that electrically connect the array substrate 2 and the external substrate 4.

  The external substrate 4 includes a control circuit 18 that outputs various signals including control signals to the array substrate 2, a common circuit 19 that supplies a common voltage to the array substrate 2, and various types of signals to the array substrate 2. A power supply circuit 20 and the like for supplying the above voltage are provided. For example, a printed circuit board or the like is used as the external substrate 4.

  The display area unit 11 is a display area in which a plurality of pixel areas each including a plurality of pixels are arranged, and is arranged in the center of the array substrate 2. In addition, the scanning line driving circuit 12, the signal line driving circuit 13, the reset control line driving circuit 14, the output control line driving circuit 15, the sensor output circuit 16, and the interface circuit 17 are included in the display area unit 11 on the array substrate 2. It is positioned and provided in an area other than the provided display area, that is, a frame area.

  The display area 11 includes a plurality of scanning lines G (n), a plurality of signal lines S (m), and a plurality of scanning lines G (n) provided in parallel with each other. Reset control line C (n) and a plurality of output control lines O (n), their scanning lines G (n), signal lines S (m), reset control lines C (n), output control lines O A plurality of sensor-incorporated pixels 11a connected to (n), respectively. The display area unit 11 has a display function for displaying an image based on video data, and a capturing function (light input function) for capturing an image of a recognition object such as a finger approaching the display area unit 11.

  FIG. 2 is a circuit configuration diagram showing a circuit configuration of the sensor-embedded pixel 11a. The sensor built-in pixel 11a is provided at each intersection of the three signal lines S (m) to S (m + 2) used for red (R), green (G), and blue (B) and the scanning line G (n). Signals used for the three pixel transistors 31 arranged, the control transistor 33 arranged at the intersection of the signal line S (m + 2) used for the reset control lines C (n) and B, and the output control lines O (n) and R A control transistor 34 disposed at the intersection of the line S (m + 3), and one photosensor 32 connected to the control transistor 33 and the control transistor 34 are provided. A buffer circuit (not shown) is provided between the control transistor 34 and the signal line S (m + 3) used for R. As the pixel transistor 31, the control transistor 33, and the control transistor 34, for example, a MOS thin film transistor or the like is used.

  The gate electrode of each pixel transistor 31 is connected to the scanning line G (n), each source electrode is connected to the signal lines S (m) to S (m + 2), and each drain electrode is a pixel. The capacitor Cls and the auxiliary capacitor Cs are connected. The pixel transistor 31, the pixel capacitor Cls, and the auxiliary capacitor Cs operate as a display function that outputs an image based on the video data described above.

  On the other hand, the optical sensor 32 includes a photoelectric conversion element 32a that converts light into electrical energy, a sensor capacitor (not shown), an amplifier circuit (not shown) that includes a source follower circuit, and the like. The optical sensor 32 is connected to the drain electrodes of the control transistor 33 and the control transistor 34. The source electrode of the control transistor 33 is connected to the signal line S (m + 2) used for B, and the gate electrode thereof is connected to the reset control line C (n). The source electrode of the control transistor 34 is connected to the signal line S (m + 3) used for R through the buffer circuit, and the gate electrode thereof is connected to the output control line O (n). The ground electrode of the optical sensor 32 is connected to a signal line GND (not shown). The optical sensor 32, the control transistor 33, and the control transistor 34 operate as a capturing function (light input function) for capturing an image of the above-described recognition target object. For example, a photodiode or the like is used as the photoelectric conversion element 32a.

  The display device 1 is not limited to a liquid crystal display device using a liquid crystal layer. For example, the display device 1 may be formed of a light emitter and formed as an organic EL display.

<Description of each circuit constituting the display device>
Each circuit included in the display device will be described with reference to FIGS.

  The scanning line driving circuit 12 sequentially outputs a scanning signal GATE to each scanning line G (n) every horizontal period, that is, every video writing period in one horizontal period, and drives each scanning line G (n). Circuit. Here, the scanning signal GATE is a signal for driving (turning on) the pixel transistor 31.

  The signal line driving circuit 13 is a circuit that outputs each video signal to each signal line S (m) in synchronization with the scanning signal GATE, and drives each signal line S (m). Here, the video signal is a signal for applying a voltage to the pixel capacitor Cls and the auxiliary capacitor Cs based on the video data. The detailed configuration and operation relating to the signal line drive circuit 13 will be described later.

  The reset control line drive circuit 14 includes a shift register (not shown) and a buffer circuit (not shown). The reset control line driving circuit 14 outputs a reset control signal CRT to each reset control line C (n) by the buffer circuit based on the shift pulse that sequentially propagates through the shift register, and outputs each reset control line C (n). It is a circuit which drives in order. Here, the reset control signal CRT is a signal for driving (turning on) the control transistor 33.

  The output control line drive circuit 15 includes a shift register (not shown) and a buffer circuit (not shown). The output control line drive circuit 15 outputs an output control signal OPT to each output control line O (n) by the buffer circuit based on the shift pulse that sequentially propagates through the shift register, and outputs each output control line O (n). It is a circuit which drives in order. Here, the output control signal OPT is a signal for driving (turning on) the control transistor 34.

  The sensor output circuit 16 includes an AD conversion circuit 16a, a shift register 16b, an output buffer 16c, and a synchronization signal generation circuit 16d. The sensor output circuit 16 converts the sensor output signal propagated from the optical sensor 32 to the shift register 16b via the control transistor 34 by the AD conversion circuit 16a into a digital signal, and stores the converted digital signal in the output buffer 16c. Thereafter, the stored digital signal is output to the control circuit 18 bit by bit as sensor output data in synchronization with the control clock output from the synchronization signal generating circuit 16d. The output buffer 16c adjusts the amplitude of the digital signal output from the shift register 16b according to the interface of the control circuit 18 or the like, or amplifies the drive signal until reaching the external circuit such as the control circuit 18 or the like. The function to perform.

  As shown in FIG. 3, the control circuit 18 includes a sensor output data processing circuit 18a, a control signal generation circuit 18b, a video data processing circuit 18c, and the like. FIG. 2 is a block diagram showing a circuit configuration of the control circuit 18. The sensor output data processing circuit 18a receives the sensor output data transmitted from the sensor output circuit 16, performs predetermined image processing on the sensor output data, and transmits the image-processed data to a host device (not shown). Send). In addition, the control signal generation circuit 18b generates a control signal according to the control command transmitted from the host device, and transmits the generated control signal to the signal line drive circuit 13 and the like. The video data processing circuit 18c includes a serial interface 41 that is an interface to the host device, a frame memory 42 that stores video data transmitted from the host device via the serial interface 41, and video data stored in the frame memory 42. A sorting / dividing circuit 43 and the like for sorting and dividing are provided. The video data processing circuit 18c receives digital video data transmitted from the host device via the serial interface 41, stores the received video data in the frame memory 42, and the rearrangement frequency dividing circuit 18c performs rearrangement. The rounded video data is transmitted to the signal line drive circuit 13. Thereby, the digital video data transmitted from the host device is rearranged in accordance with the circuit structure of the signal line driving circuit 13 of the array substrate 2 and transmitted.

  Since the control circuit 18 includes a high-speed logic circuit and a memory circuit, it is more advantageous in terms of cost and size to be formed as an integrated LSI than to be formed as a separate LSI (integrated circuit). The interface to the host device is a low voltage (1.8 V) / high frequency (40 MHz) serial interface, but the interface to the array substrate 2 on which the signal line drive circuit 13 and the like are arranged is a high voltage (3 V) / low frequency. A frequency dividing interface (1 MHz) is used. This is because the operation of a circuit formed on an insulating substrate such as the array substrate 2 is slower than the operation of a circuit formed on a silicon substrate such as the external substrate 4.

<Detailed Configuration and Operation of Signal Line Driver Circuit>
Returning to FIG. 1, the detailed configuration and operation of the signal line driving circuit 13 will be described.

  The signal line driving circuit 13 is a data latch circuit 13a for storing the video data transmitted from the control circuit 18, and DA conversion for converting the digital video data stored in the data latch circuit 13a into an analog signal and then outputting it as a video signal. Circuit 13b, precharge circuit 13c for precharging each signal line S (m) to a predetermined potential, connection between the output of the DA converter circuit 13b, the output of the precharge circuit 13c, and the like, and each signal line S (m) A selection circuit 13d for selectively performing the above. The precharge circuit 13c is supplied from the power supply circuit 20 on the basis of the precharge control signal PRCB used for the precharge control signals PRCG and B used for the precharge control signals PRCR and G used for R transmitted from the control circuit 18. Then, the precharge voltage Vprc adjusted by the control circuit 18 is supplied to each signal line S (m).

  FIG. 4 is a configuration diagram showing the configuration of the selection circuit 13d in the signal line driving circuit 13. As shown in FIG. As shown in the figure, each signal line S (m) is divided into a plurality of signal line groups SS (j: positive integer). Each signal line S (m) includes, for example, a plurality of signal line groups SS (j) with three signal lines S (m) to S (m + 2) used for RGB as one signal line group SS (j). It is divided into Accordingly, one signal line group SS (j) is a set of three signal lines S (m) to S (m + 2).

  A plurality of data latch circuits 13a, DA conversion circuits 13b, and precharge circuits 13c are provided on the array substrate 2 in correspondence with the respective signal line groups SS (j). The plurality of data latch circuits 13a are connected to the respective DA conversion circuits 13b.

  As shown in the figure, the selection circuit 13d includes three switches connected in correspondence to the three signal lines S (m) to S (m + 2) constituting each signal line group SS (j). It is composed of the elements SWA1 to SWA3 and a plurality of switch elements SWB1 to SWB3 connected in correspondence to the switch elements SWA1 to SWA3.

  The switch elements SWA1 to SWA3 are subjected to drive control, that is, on / off control (open / close control) by switch control signals A1 to A3 transmitted from the control circuit 18. Further, the switch elements SWB1 to SWB3 are drive-controlled, that is, turned on / off (open / closed) by switch control signals B1 to B3 transmitted from the control circuit 18.

  The selection circuit 13d includes connection of each DA converter circuit 13b to each signal line group SS (j), each precharge circuit 13c to each signal line group SS (j), and each signal line group SS (j). Either of the connection of the AD conversion circuit 16a is selected.

  Here, when each DA converter circuit 13b is connected to the R signal lines S1, S4,..., S (m−2), the switch control signal A1 and the switch control signal B1 are activated. Accordingly, each switch element SWA1 and each switch element SWB1 are turned on, and the R signal lines S1, S4,..., S (m−2) and each DA converter circuit 13b are connected. As a result, the output of each DA converter circuit 13b is written to the R signal lines S1, S4,..., S (m−2). Similarly, when each DA converter circuit 13b is connected to the G signal lines S2, S5,..., S (m−1), the switch control signal A2 and the switch control signal B1 are activated. Further, when each DA converter circuit 13b is connected to the B signal lines S3, S6,..., S (m), the switch control signal A3 and the switch control signal B1 are activated.

  As a result, the digital video data stored in each data latch circuit 13a is converted into an analog signal by each DA conversion circuit 13b and then written to each signal line S (m) as a video signal.

  When each precharge circuit 13c is connected to the B signal lines S3, S6,..., S (m), the switch control signal A3 and the switch control signal B2 are activated. In response to this, each switch element SWA3 and each switch element SWB2 are turned on, and the B signal lines S3, S6,..., S (m) and each precharge circuit 13c are connected.

  As a result, the precharge voltage Vprc is written to the B signal lines S3, S6,..., S (m), and the written precharge voltage Vprc is applied to each light according to the drive of the control transistor 33 by the reset control signal CRT. It is supplied to the sensor 32.

  Of course, when each precharge circuit 13c is connected to the R signal lines S1, S4,..., S (m−2), the switch control signal A1 and the switch control signal B2 can be activated. . Accordingly, each switch element SWA1 and each switch element SWB2 are turned on, and the R signal lines S1, S4,..., S (m−2) and each precharge circuit 13c are connected. Similarly, when each precharge circuit 13c is connected to the G signal lines S2, S5,..., S (m−1), the switch control signal A2 and the switch control signal B2 can be activated. is there. Accordingly, each switch element SWA2 and each switch element SWB2 are turned on, and the G signal lines S2, S5,..., S (m−1) and each precharge circuit 13c are connected.

  When each AD converter circuit 16a is connected to the R signal lines S1, S4,..., S (m−2), the switch control signal A1 and the switch control signal B3 are activated. Accordingly, each switch element SWA1 and each switch element SWB3 are turned on, and the R signal lines S1, S4,..., S (m-2) and each AD converter circuit 16a are connected. .

  Thereby, the sensor output signal output from each optical sensor 32 is transmitted to each AD conversion circuit 16a according to the drive of the control transistor 34 by the output control signal OPT.

  Of course, when each AD converter circuit 16a is connected to the G signal lines S2, S5,..., S (m−1), the switch control signal A2 and the switch control signal B3 can be made active. . In response to this, each switch element SWA2 and each switch element SWB3 are turned on, and the G signal lines S2, S5,..., S (m-1) and each AD converter circuit 16a are connected. . Similarly, when each AD conversion circuit 16a is connected to the B signal lines S3, S6,..., S (m), the switch control signal A3 and the switch control signal B3 can be made active. Accordingly, each switch element SWA3 and each switch element SWB3 are turned on, and the B signal lines S3, S6,..., S (m) and each AD converter circuit 16a are connected.

<Explanation about photodetection sensitivity of photosensor>
The light detection sensitivity of the optical sensor 32 described with reference to FIG. 2 will be described.

  The light detection sensitivity of the light sensor 32 is proportional to the size of the light sensor 32, in particular, the width of the light sensor 32. The minimum width of the optical sensor 32 is limited by the processing accuracy of the manufacturing process, and the maximum width is limited by the size of the display area unit 11. Here, if the width of the photosensor 32 is increased too much in order to increase the photodetection sensitivity, the aperture ratio is significantly reduced. Accordingly, the width of the optical sensor 32 needs to be determined in consideration of a trade-off with the aperture ratio. The aperture ratio indicates the ratio of the area of a portion through which light passes except for the wiring of one pixel and the transistor to the entire area of one pixel. The higher the aperture ratio, the higher the light transmittance. Means that.

  For example, a plurality of pixels provided with a photosensor 32 having the same width as the width of the photosensor 32 are arranged in the pixel area, and the pixel area is a display area 11 as a display area. By disposing a plurality of optical detectors, the light detection sensitivity of the display device 1 can be maximized. In this case, although it is advantageous in a dark place, the light detection sensitivity is too high, and therefore, in a bright place, too much current flows depending on the detected amount of received light, and saturation of the captured image occurs (for example, the entire white area is white). Captured image). Furthermore, since the characteristic variation of each optical sensor 32 directly affects the variation of the captured image, unevenness of the captured image is likely to occur.

  Therefore, the display apparatus 1 arranges a plurality of pixels including the photosensors 32 that are increased in an equal difference from the photosensors 32 having a small width in the pixel region. By sequentially saturating the photosensors 32 having different widths in the pixel area, it is possible to realize a function of capturing a recognition object in a wide range from a dark place to a bright place. Specifically, for example, each of the optical sensors 32 of 9 levels of difference having a width of 4 μm, 8 μm, 12 μm, 16 μm, 20 μm, 24 μm, 28 μm, 32 μm, and 36 μm is arranged in a 3 × 3 pixel region, A plurality of the pixel areas are arranged in the display area unit 11 which is a display area.

  Thereby, by adjusting the width of the optical sensor 32, the light detection sensitivity can be adjusted (calibrated).

  In addition, the display device 1 further includes a plurality of photosensors 32 having a width equivalent to the maximum width of the plurality of photosensors 32 having the same level of difference 9 in addition to the plurality of photosensors 32 having the level of difference of 9 levels. It is also possible to add to the area.

  FIG. 5 shows a pixel region in which a plurality of photosensors 32 with nine levels of equality and a plurality of photosensors 32 having a width equivalent to the maximum width of the plurality of photosensors 32 with nine levels of equality are arranged in a display region. 3 is a plan view showing a configuration in which a plurality of display areas 11 are arranged. FIG. The numbers shown in the figure represent the width (unit: μm) of the optical sensor 32 provided in one pixel. The display device 1 has a configuration in which a 4 × 4 pixel region in which a plurality of optical sensors 32 having nine different widths are arranged is repeatedly arranged in the display region unit 11. This 4 × 4 pixel region further includes seven photosensors 32 having a maximum width of 36 μm, which is the maximum width of the photosensor 32 having nine levels of difference, compared with the nine photosensors having nine levels of difference from 4 μm to 36 μm. It has been added. For this reason, the pixel region in the figure is composed of photosensors 32 having a maximum width (36 μm) of half of a total of 16 photosensors 32 arranged in a 4 × 4 pixel.

  The photodetection sensitivity of the display region 11 in which only the uniform level photosensor 32 having a width of 36 μm is arranged in the 3 × 3 pixel region, and the photosensor 32 having a difference of 9 levels from 4 μm to 36 μm are 3 × 3. When comparing the light detection sensitivity of the display region 11 arranged in the pixel region, the latter light detection sensitivity is reduced to about 5/8 compared to the former light detection sensitivity. However, the optical detection sensitivity can be improved without lowering the aperture ratio by further adding a 36 μm optical sensor 32 which is the maximum width of the optical sensors 32 having the same difference of 9 levels described with reference to FIG. be able to.

  Accordingly, the display device 1 shown in FIG. 5 realizes calibration for suppressing blackout and whiteout of the captured image by using a plurality of optical sensors 32 having nine levels of equality, and a plurality of levels having nine levels of difference. By further adding a plurality of optical sensors 32 of 36 μm which is the maximum width of the optical sensor 32, it is possible to increase the photodetection sensitivity as a whole.

  It should be noted that the plurality of optical sensors 32 constituting the equal difference level may be at the equal ratio level. In addition, the width of the optical sensor 32 to be added has been described using a width equivalent to the maximum width of nine equal differences, but may be larger than the maximum width. Thereby, the light detection sensitivity can be further improved.

  Further, in FIG. 5, the pixel area including 4 × 4 pixels is taken as an example, and the number of the optical sensors 32 added to the 3 × 3 pixel area is described as seven. The quantity is not limited to this. However, if the number of added photosensors 32 is too small, it is not possible to improve the light detection sensitivity characteristics. Therefore, the number of added photosensors 32 is at least the number of photosensors 32 with nine equalities. It is desirable that it is 1/3 or more.

  Furthermore, it is desirable to arrange each photosensor 32 at random in the pixel region. As a result, it is possible to suppress the variation in the sensor characteristics generated in the manufacturing process and the like, and to prevent periodic unevenness during image capture.

  2 and FIG. 5, one photosensor 32 is arranged for one pixel. However, the present invention is not limited to this, and in the case of a display device with a high number of pixels and high pixel density, for example, one for every four pixels. Alternatively, the arrangement density of the optical sensors 32 may be lowered. Of course, the arrangement density may be increased by associating one photosensor 32 with each of the RGB sub-pixels constituting one pixel.

  Further, since it is not desirable that the light transmittance of the pixel or sub-pixel in which the light sensor 32 is arranged is different, the light transmission is performed so as to cover the top of the light sensor 32 using a metal wiring that supplies a potential to the light sensor 32. It is desirable to reduce the difference in rates. By adopting such a configuration, the light shielding layer made of metal wiring serves to shield light from the backlight against light incident from the array substrate 2 side, and is incident from the array substrate 2 side. This is desirable because it plays a role of reflecting a part of the light to enter the optical sensor 32. For example, as shown in FIG. 6, the transmittance of the pixels or sub-pixels is adjusted to be substantially equal by changing the width of the polysilicon (p-Si) layer 32b or the Al metal wiring layer 32c.

  Thereby, by making the transmittance of the pixels or sub-pixels substantially the same, it is possible to prevent display quality degradation such as luminance variations of the display device 1.

  Further, when the optical sensor 32 is arranged in any of the RGB sub-pixels, the transmittance of the sub-pixel in which the optical sensor 32 is arranged is reduced, so that the white balance is prevented from deteriorating when white is displayed. Therefore, it is desirable to adjust the widths of the sub-pixels in which the photosensors 32 are arranged and the widths of other sub-pixels so that the transmittance of each sub-pixel is substantially equal. At this time, the circuit for driving the optical sensor 32 can be arranged in a sub-pixel where the optical sensor 32 is not arranged. It should be noted that the degree of gradation difference that can be used to detect a recognition object such as a finger depends on the algorithm of the detection determination program stored in the control circuit 18.

<Description of operation of pixel with built-in sensor>
The operation of the sensor built-in pixel 11a will be described with reference to FIG. 2, FIG. 4, and FIG.

  FIG. 7 is a timing chart of the processing operation in the sensor built-in pixel 11a. In the figure, a scanning signal GATE (n) for the pixel transistor 31, a reset control signal CRT (n) for the photosensor 32, an output control signal OPT (n) for the photosensor 32, and a precharge control signal for the precharge circuit 13c. The relationship between PRCR, PRCG, and PRCB is shown. Here, one horizontal period is composed of a horizontal blanking period and a video writing period.

  At time t1 in one horizontal period, when the precharge control signal PRCB becomes high level by the control circuit 18, the switch control signal A3 and the switch control signal B2 become active at a predetermined timing, and each switch element SWA3 and Each switch element SWB2 is turned on. As a result, the B signal lines S3, S6,..., S (m) are connected to the respective precharge circuits 13c, and the photosensors are connected from the precharge circuit 13c to the B signal lines S3, S6,. A precharge voltage Vprc (for example, 5 V) for 32 is written.

  Of course, at the same time, the precharge control signal PRCR can be set to the high level by the control circuit 18. Thereby, at a predetermined timing, the switch control signal A1 and the switch control signal B2 are also activated, and each switch element SWA1 and each switch element SWB2 are turned on. As a result, the R signal lines S1, S4,..., S (m-2) and the respective precharge circuits 13c are connected, and the R signal lines S1, S4,. ) Is written with the precharge voltage Vprc for the optical sensor.

  Of course, at the same time, the precharge control signal PRCG can be set to the high level by the control circuit 18. Thus, at a predetermined timing, the switch control signal A2 and the switch control signal B2 are in the active state, and the switch elements SWA2 and the switch elements SWB2 are turned on. As a result, the G signal lines S2, S5,..., S (m-1) and the respective precharge circuits 13c are connected, and the G signal lines S2, S5,. ) Is written with the precharge voltage Vprc for the optical sensor.

  In the present embodiment, as shown in FIG. 2, since the optical sensor 32 is connected to the signal line used for B via the control transistor 33, it is not necessary to set the precharge control signals PRCR and PRCG to the high level. However, the precharge control signals PRCR and PRCG may be set to the high level as described above in consideration of the case where another optical sensor 32 is connected to the signal line used for R or the signal line used for G. Is possible.

  Next, at time t2 in one horizontal period, when the reset control signal CRT (n) becomes high level by the reset control line driving circuit 14, the control transistor 33 connected to the reset control line C (n) is turned on. Thus, the precharge voltage Vprc (5 V) written to the B signal lines S3, S6,..., S (m) is precharged to the sensor capacitor constituting the photosensor 32 of the sensor built-in pixel 11a.

  Further, when the output control signal OPT (n) becomes high level by the output control line driving circuit 15, the control transistor 34 connected to the output control line O (n) is turned on, and the photosensor of the sensor built-in pixel 11a. 32 is electrically connected to a signal line S (m) (corresponding to S (m + 3) used for R shown in FIG. 2). At this time, when the potential of the sensor capacitor is high, the potential output to the signal line S (m) hardly changes from 5V. In this way, the sensor output signal is output from the optical sensor 32 to the signal line S (m).

  Subsequently, when the scanning signal GATE (n) becomes a high level by the scanning line driving circuit 12 at time t3 in one horizontal period, the signal signal driving circuit 13 outputs a video signal to each signal line S (m). Writing starts. At this time, the switch control signal A1 and the switch control signal B1 are activated, and each switch element SWA1 and each switch element SWB1 are turned on. As a result, the R signal lines S1, S4,..., S (m−2) and each DA converter circuit 13b are connected. The analog video signal output from each DA converter circuit 13b is written to the R signal lines S1, S4,..., S (m−2). Similarly, analog video signals output from the DA conversion circuits 13b are also applied to the G signal lines S2, S5,..., S (m-1) and the B signal lines S3, S6,. Is written. Thereafter, the writing of the video signal is finished, and one horizontal period is finished as the writing is finished. One horizontal period is set to a very short period of 50 μs, for example.

  As described above, the precharge and output processing for the optical sensor 32 and the video signal writing processing are sequentially performed, so that the above-described capturing function (light input function) for capturing an image of the external recognition target and video data are used. Display function to output images. Detailed processing in the capture function (light input function) and the display function will be described later.

  The driving method for sharing the signal line used when outputting the sensor output signal from the optical sensor 32 to the sensor output circuit 16 with the signal line S (m) for video writing has been described. It is also possible to use a dedicated line for reading sensor signals.

  Here, a method for detecting a recognition object will be briefly described. The time from when the precharge voltage Vprc is applied after the control transistor 33 is turned on to when the sensor transistor 34 is turned on and the sensor output signal is output from the optical sensor 32 to the signal line S (m) and taken out is expressed as “ It is defined as “exposure time”. The output of the optical sensor 32 varies depending on the magnitude of the precharge voltage Vprc, the intensity of light irradiated on the optical sensor 32, and the exposure time. That is, the recognition target close to the display area unit 11 is detected by detecting the intensity of the light applied to the optical sensor 32 from the magnitude of the precharge voltage Vprc, the length of the exposure time, and the amount of light leakage of the optical sensor 32. An object such as a finger can be detected.

  It is desirable to adjust the exposure time and the precharge voltage Vprc so that the captured image to be acquired is not blacked out or whited out. That is, as the external light is stronger, the light leak amount of the optical sensor 32 becomes larger and the charge is discharged in proportion to the exposure time. Therefore, the precharge voltage Vprc needs to be shortened when a constant voltage is applied. There is. Conversely, when the external light is weak, the exposure time should be increased. If the discharge is large even if the exposure time is shortened, the precharge voltage Vprc should be set high.

  That is, the display device 1 can finely adjust the photodetection sensitivity by appropriately controlling the exposure time and the precharge voltage Vprc by the control circuit 18. The exposure time and precharge voltage Vprc can be controlled independently.

  Further, the method is not limited to a method of recognizing a recognition target object by capturing a shadow of a recognition target object such as a finger caused by external light. For example, by capturing backlight light reflected by a recognition target object such as a finger. You may make it recognize a recognition target object. This is an effective method when the ambient light illuminance is low.

  Since the backlight light reflected by the recognition object such as a finger has lower illuminance than external light, it is possible to reliably saturate all of the plurality of photosensors 32 having different photodetection sensitivities arranged in the portion where the finger is close. As a result, the existence of the authentication target cannot be reliably grasped. Also, the backlight light itself may be suppressed. Therefore, at least a part of the data (sensor signal values) acquired from the plurality of optical sensors 32 having different widths that are differentially or equally different is equal to or equal to the maximum value of the width that is differentially or equally different. The sensor sensitivity of the entire display device 1 may be increased by replacing with data (sensor signal values) acquired from a plurality of optical sensors 32 having a width larger than the maximum value. For example, by using an average value of data (sensor signal values) taken from a plurality of photosensors 32 having a width equal to or greater than the maximum value of differently or equally different widths, The sensor output data processing circuit 18a or the host device executes an image processing operation for replacing data (sensor signal values) acquired from a plurality of optical sensors 32 having different widths in the same ratio. By this replacement, even if the light reflected by the recognition object is weak, the data captured by the photosensor 32 with high photodetection sensitivity is regarded as data captured by the photosensor 32 with low photodetection sensitivity. An object approaching the device 1 can be recognized more reliably.

<Description of display processing>
The control circuit 18 gives the video data supplied from the host device to the signal line driving circuit 13. Thereby, in the first one horizontal period, the signal line drive circuit 13 uses the voltage of the video data supplied to each signal line S (m) as the S / N sensitivity at the corresponding position in the horizontal direction in the uppermost column of the display image. Set the voltage according to.

  In the horizontal period described above, the scanning line driving circuit 12 drives the scanning line G (1) corresponding to the uppermost column. As a result, the pixel transistor 31 connected to the scanning line G (1) becomes conductive, and a video signal (voltage corresponding to the corresponding S / N sensitivity) is written to the pixel capacitor Cls connected to the pixel transistor 31. . That is, the pixel capacitance Cls is charged according to the S / N sensitivity. Thereby, the light transmission amount in the pixel capacitor Cls becomes a transmission amount according to the S / N sensitivity, and the uppermost row of the display area 11 displays the uppermost row of the display image.

  In the subsequent horizontal period, the second column of the display area unit 11 displays the second column of the video data by the same processing while maintaining the display of the uppermost column. Thereafter, similar processing is sequentially performed, and in the last horizontal period in the frame period, the lowermost column of the display area unit 11 displays the lowermost column of the video data. In this way, all the video data is displayed in one frame period. Note that video data is continuously displayed by performing display in the one frame period in each subsequent frame period.

<Explanation of capture processing (light input processing)>
The control circuit 18 gives the video data supplied from the outside such as the host device to the signal line drive circuit 13, whereby the display device 1 performs the above-described display processing and displays the video data on the display area unit 11. Further, the display device 1 performs the following process in the horizontal blanking period between the video writing period and the video writing period.

  First, in the first horizontal blanking period, the control circuit 18 controls the voltage of each signal line S (m) to a predetermined precharge voltage Vprc, and further controls the reset control line C (1) in the uppermost column and the output control. The line O (1) is controlled to a high level. The sensor built-in pixel 11a in the uppermost column is charged until the sensor capacitance constituting the photosensor 32 reaches a predetermined precharge voltage. After precharging, the control circuit 18 controls the reset control line C (1) and the output control line O (1) to a low level. And when light, such as environmental light and backlight light, is irradiated to each photoelectric conversion element 32a, discharge of a sensor capacity will advance.

  Next, the reset control line drive circuit 14 and the output control line drive circuit 15 control the output control line O (n) to a high level when the exposure time corresponding to the exposure time data set by the control circuit 18 has elapsed. The control transistor 34 is turned on to operate the buffer circuit connected between the control transistor 34 and the signal line S (m) (corresponding to S (m + 3) used for R shown in FIG. 2). As a result, the buffer circuit temporarily holds the voltage of the sensor capacitance at that time, and then outputs the voltage to the signal line S (m) as a sensor output signal. In response to this, the sensor output circuit 16 converts the sensor output signal input from each signal line S (m) into a serial signal and outputs it to the control circuit 18 as sensor output data.

  In the subsequent horizontal blanking period, the sensor output circuit 16 outputs the serial signal of the second column to the control circuit 18 by the same processing. Thereafter, similar processing is sequentially performed, and in the final horizontal blanking period, the sensor output circuit 16 outputs the serial signal in the bottom row to the control circuit 18. Thereby, during the horizontal blanking time, the control circuit 18 acquires each serial signal, that is, a two-tone image. By continuing such processing, the control circuit 18 continuously acquires two-tone images.

  According to the present embodiment, the photodetection sensitivity of the pixel region (and display region) is adjusted by the plurality of photosensors 32 having differently or equally different widths such as 9 levels of 4 μm to 36 μm. Make it possible. Furthermore, it is possible to improve the photodetection sensitivity of the pixel area (and display area) by using a plurality of photosensors 32 having a width equal to or larger than the maximum value of different widths such as 36 μm that are differentially or equally different. And Accordingly, the display device 1 can appropriately and reliably obtain optical information regardless of the intensity of external light illuminance.

  According to the present embodiment, the number of photosensors 32 having a width that is equal to or greater than the maximum value of differently or equally different widths is a width that is differently or equally different. By setting it to 1/3 or more of the quantity of the optical sensors 32 to have, the light detection sensitivity of a pixel area can be improved more reliably.

  According to the present embodiment, a plurality of photosensors 32 having different widths that are differentially or equally different from each other, and a plurality of optical sensors 32 having a width that is equal to or greater than the maximum value of differently or equally different widths. By randomly arranging the photosensors 32 in the pixel region, it is possible to suppress the influence of variations in photosensor characteristics that occur during the manufacturing process, and to prevent periodic unevenness during image capture.

  According to the present embodiment, by further including a control circuit that adjusts the exposure time and / or precharge voltage of the optical sensor 32 in accordance with the external light illuminance captured by the optical sensor 32, Crushing can be reliably prevented.

  According to the present embodiment, since the transmittance of the plurality of pixels is substantially equal, it is possible to prevent deterioration in display quality such as luminance variation that occurs when a plurality of photosensors 32 having different widths are arranged. .

  According to the present embodiment, the white balance of the display device 1 can be prevented from being lowered by making the transmittances of the red, green, and blue sub-pixels substantially equal.

  According to the present embodiment, at least a part of the sensor signal values from the plurality of photosensors 32 having differently or equally different widths is equivalent to the maximum value of the differently or equally different widths. Alternatively, by replacing the sensor signal values from the plurality of photosensors 32 having a width larger than the maximum value, the object close to the display device 1 can be more reliably recognized even when the external light illuminance is low. .

It is a block diagram which shows the schematic structure of the display apparatus in this Embodiment. It is a circuit block diagram which shows the circuit structure of the pixel with a built-in sensor. It is a block diagram which shows the circuit structure of a control circuit. It is a block diagram which shows the structure of the selection circuit in a signal line drive circuit. A plurality of pixel regions in which a plurality of photosensors with 9 levels of equality and a plurality of photosensors having a width equivalent to the maximum width of the plurality of photosensors with 9 levels of equality are arranged in a display region, which is a display region FIG. It is a front view which shows the front of the optical sensor from which width differs. It is a timing chart of processing operation in a sensor built-in pixel.

Explanation of symbols

A1 to A3, B1 to B3, switch control signal PRCR, PRCG, PRCB, precharge control signal C, reset control line G, scanning line O, output control line S, signal line 1, display device 2, array substrate 3, flexible Substrate 4 ... External substrate 11 ... Display area 11a ... Sensor built-in pixel 12 ... Scanning line drive circuit 13 ... Signal line drive circuit 13a ... Data latch circuit 13b ... DA conversion circuit 13c ... Precharge circuit 13d ... Selection circuit 14 ... Reset control Line drive circuit 15 ... Output control line drive circuit 16 ... Sensor output circuit 16a ... AD converter circuit 16b ... Shift register 16c ... Output buffer 16d ... Synchronization signal generation circuit 17 ... Interface circuit 18 ... Control circuit 18a ... Sensor output data processing circuit 18b ... Control signal generation circuit 18c ... Division circuit 18c ... Video data Processing circuit 19 ... Common circuit 20 ... Power supply circuit 31 ... Pixel transistor 32 ... Optical sensor 32a ... Photoelectric conversion element 32b ... Polysilicon layer 32c ... Metal wiring layer 33, 34 ... Control transistor 41 ... Serial interface 42 ... Frame memory 43 ... Minute Circuit

Claims (8)

A display area in which a plurality of pixel areas each having a plurality of pixels are arranged;
A plurality of sensors with different widths provided in the pixel region in an equal or different ratio;
A plurality of sensors having a width equal to or greater than the maximum value of the width provided in the pixel region;
A display device comprising:   The number of sensors having a width equal to or greater than the maximum value of the differentially or equally different widths is 1/3 of the number of sensors having the differentially or equally different widths. It is the above, The display apparatus of Claim 1 characterized by the above-mentioned.   A plurality of sensors having different widths with the same or different ratio and a plurality of sensors having a width equal to or greater than the maximum value of the different or different widths in the pixel region. The display device according to claim 1, wherein the display device is arranged at random.   4. The display device according to claim 1, further comprising a control circuit that adjusts an exposure time and / or a precharge voltage of the sensor in accordance with an illuminance of outside light captured by the sensor. 5. .   The display device according to claim 1, wherein the transmittance of the plurality of pixels is equal. The pixel includes red, green, and blue sub-pixels,
The plurality of sensors having different widths with the same or different ratio and the plurality of sensors having a width equal to or larger than the maximum value of the different widths with the same or different ratio are the sub pixels. The display device according to claim 1, wherein the display device is provided for at least one of them.   The display device according to claim 6, wherein the red, green, and blue sub-pixels have the same transmittance.   The control circuit has at least a part of sensor signal values from the plurality of sensors having different widths that are different in the difference or the same ratio as the maximum value of the width that is different in the difference or the difference. 8. The exposure time and / or the precharge voltage of the sensor is adjusted by replacing with a sensor signal value from a plurality of sensors having a width greater than the value. 9. Display device.

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