JP2010182064A - Display, electronic device, and method of driving display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent erroneous detection of a detected object caused by the change of an image. <P>SOLUTION: A plurality of pixel circuits P display images in a display area A. A plurality of detecting circuits Q are arranged in the display area A to output detection signals IS corresponding to the light receiving amount of a photodetector 36. A data generating section 62 generates detection data D sequentially from the detection signals IS output from the plurality of detecting circuits Q. A storage circuit 70 stores reference data Dref compared with the detection data D. A determining section 68 determines the presence/absence of the detected objects sequentially by comparison between the detection data D and the reference data Dref. An image change detecting section 64 detects the change of the images displayed in the display area A. A data updating section 66 updates the reference data Dref stored in the storage circuit 70, to the detection data D after the change when the image change detecting section 64 detects the change of images. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for displaying an image and detecting an object to be detected (hereinafter referred to as “detected object”).

  Conventionally, a display device (touch panel) having both a function of displaying an image and a function of detecting an object to be detected has been proposed. For example, in Patent Document 1, detection data (image data) is sequentially generated from detection signals generated by a plurality of detection bodies (for example, optical sensors) in a display area, and detection is performed according to the difference between successive detection data. Techniques for detecting the presence and position of an object are disclosed.

JP 2006-244446 A

  By the way, since a capacitance is parasitic between an element (for example, a wiring or a pixel) used for displaying an image and an element (for example, a wiring or a detection object) used for detecting an object to be detected, it is displayed in the display area. As the image changes, the detected data also changes. Therefore, the difference between the detection data that follow each other increases in conjunction with the change in the image, and there is a possibility that the detection object is erroneously detected even though there is actually no object to be detected. In view of the above circumstances, an object of the present invention is to prevent erroneous detection of an object to be detected due to a change in an image.

  In order to solve the above-described problems, a display device according to the present invention includes a plurality of pixel circuits that display an image in a display area, and a detection signal that is arranged in the display area and that corresponds to the amount of light received by a photodetector. A plurality of detection circuits that output, data generation means for sequentially generating detection data from detection signals output from the plurality of detection circuits, storage means for storing reference data to be compared with the detection data, detection data and reference A determination unit that sequentially determines the presence or absence of an object to be detected by comparison with data, an image change detection unit that detects a change in an image displayed in a display area, and an image change detection unit that detects a change in an image And data updating means for updating the reference data used for determination by the determination means to the detected data after the change. In the above aspect, since the reference data is updated to the detection data after the change when the image in the display area changes, it is possible to prevent erroneous detection of the detected object due to the change in the image. . The display device according to the present invention is used in various electronic devices (for example, personal computers and mobile phones).

  The detected object means an object (an object on the display area) that is a detection object by the detection circuit, and includes a finger or a pen (stylus pen) that indicates an arbitrary position in the display area, for example. is there. The change in the image detected by the image change detection means means a change (change in image data) that affects the detection signal output from each detection circuit, and the hue or gradation (brightness) of each pixel constituting the image. ) And saturation changes.

  In a preferred aspect of the present invention, the data update unit does not update the reference data used for determination by the determination unit when the image change detection unit does not detect a change in the image. In the above aspect, since the update of the reference data is not executed when the image of the display area does not change, the processing load by the data updating unit is compared with the configuration in which the reference data is updated every time the determination by the determination unit. There is an advantage that (the number of times of updating reference data) is reduced.

  In a preferred aspect of the present invention, the determination unit stops the determination during the detection of the image change by the image change detection unit. In the above aspect, there is an advantage that the possibility of erroneous detection of the detection object is reduced as compared with the configuration in which the detection of the detection object is continued even during the detection of the change in the image.

  A method for detecting a change in an image displayed in the display area is arbitrary in the present invention. For example, a configuration is adopted in which a change in an image is detected by a notification from an information processing device that designates an image displayed in the display area. In consideration of the fact that the detection data reflects the image in the display area, a mode in which a change in the image is detected according to a difference between a plurality of detection data generated at different times is also suitable. The configuration for detecting an image change from the detection data has an advantage that it is not necessary to install a special function for notifying the image change in the information processing apparatus. However, the configuration for notifying the change of the image from the information processing apparatus has an advantage that the processing load by the image change detecting means is reduced as compared with the configuration for detecting the change of the image from the detection data.

  The present invention is also specified as a method for driving a display device. In the driving method according to the present invention, detection data is sequentially generated from detection signals output from a plurality of detection circuits, the presence / absence of an object to be detected is sequentially determined by comparing the detection data and reference data, and the display area is displayed. When the displayed image changes, the reference data used for determination is updated to the detected data after the change. According to the above method, the same effect as the display device according to the present invention is realized.

1 is a block diagram of a display device according to a first embodiment. It is a circuit diagram of a detection circuit. It is a block diagram of a detection processing circuit. It is a timing chart which shows the specific example of operation | movement of a display apparatus. It is a flowchart of operation | movement of a detection process circuit. It is a flowchart of image change information management. It is a flowchart of operation | movement of the detection processing circuit which concerns on 2nd Embodiment. It is a flowchart of an image change detection. It is a timing chart which shows the specific example of operation | movement of a detection process circuit. It is a perspective view of an electronic device (personal computer). It is a perspective view of an electronic device (cellular phone). It is a perspective view of an electronic device (personal digital assistant).

<A: First Embodiment>
The display device according to the first embodiment of the present invention is a display device with a detection function (touch panel) having both a function of displaying an image and a function of detecting an object to be detected (a pen or a user's finger). As shown in FIG. 1, the display device 100 includes a driven element unit 10, a display drive circuit 52, a detection drive circuit 54, a timing control circuit 56, and a detection processing circuit 60.

  The driven element unit 10 includes a plurality of pixel circuits P used for displaying an image and a plurality of detection circuits Q used for detecting an object to be detected. The structural relationship between the pixel circuit P and the detection circuit Q is arbitrary. For example, a configuration in which a plurality of pixel circuits P and a plurality of detection circuits Q are arranged on a common substrate, or a plurality of detection circuits on the observation side of a display body (liquid crystal panel) on which the plurality of pixel circuits P are formed. A configuration in which a detection body on which Q is formed is disposed.

  The plurality of pixel circuits P are arranged in a matrix in the display area A over the x direction and the y direction intersecting each other. Note that scanning lines and signal lines for supplying signals to the pixel circuits P are omitted for convenience. Each pixel circuit P includes a liquid crystal capacitor in which liquid crystal is sealed in a gap between the pixel electrode and the counter electrode.

  The timing control circuit 56 in FIG. 1 controls the display drive circuit 52 and the detection drive circuit 54 by outputting various control signals that define the operation of the display device 100. Specifically, the synchronization signal SYNC defining the unit period (for example, vertical scanning period) V (V [1], V [2], V [3],...) Is sent from the timing control circuit 56 to the display driving circuit 52. And supplied to the detection drive circuit 54 (see FIG. 4).

  The display driving circuit (scanning line driving circuit and signal line driving circuit) 52 in FIG. 1 drives each of the plurality of pixel circuits P. Image data G indicating an image is sequentially supplied from the information processing apparatus (for example, a personal computer) 200 to the display drive circuit 52. The display driving circuit 52 drives each pixel circuit P so that an image indicated by the image data G is displayed in the display area A. Specifically, the display drive circuit 52 sequentially selects a plurality of pixel circuits P in units of rows within the unit period V defined by the synchronization signal SYNC, and sets a voltage corresponding to the image data G to the selected row. This is supplied to the liquid crystal capacitance of each pixel circuit P.

  In the driven element unit 10, M control lines 12 extending in the x direction and N detection lines 14 extending in the y direction are formed (M and N are natural numbers). Each detection circuit Q is arranged at a position corresponding to each intersection of the control line 12 and the detection line 14, and is arranged in a matrix of vertical M rows × horizontal N columns in the display area A. In FIG. 1, the case where the detection circuit Q is arranged for each pixel circuit P is illustrated for convenience, but the relationship between the number and position of the pixel circuit P and the detection circuit Q is arbitrarily changed.

  FIG. 2 representatively shows the detection circuit Q in the j-th column (j = 1 to N) belonging to the i-th row (i = 1 to M). As shown in FIG. 2, the detection circuit Q includes a light detector 36 and a circuit unit 38. The light detector 36 is a light receiving element (for example, a photodiode) that generates a photocurrent Ip having a current amount corresponding to the received light amount. The amount of light received by the light detector 36 changes depending on whether or not the object to be detected is present on the display area A (whether or not the display area A is hidden by the shadow of the object to be detected). The amount of current changes according to the presence or absence of an object to be detected.

  The circuit unit 38 generates a detection signal Is corresponding to the photocurrent Ip and outputs it to the detection line 14. As shown in FIG. 2, the circuit unit 38 includes an amplification transistor 382, a selection transistor 384, and an initialization transistor 386. The conductivity type of each transistor in the circuit unit 38 is arbitrary. Further, the control line 12 of FIG. 1 includes an initialization line 121 and a selection line 122 as shown in FIG.

  The amplification transistor 382 and the selection transistor 384 are connected in series between the power supply line (power supply line) 16 and the detection line 14. A predetermined potential VRS is supplied to the feeder line 16. The gate of the amplification transistor 382 is connected to the photodetector 36. The initialization transistor 386 is interposed between the gate of the amplification transistor 382 and the power supply line 16. The gate of the selection transistor 384 is connected to the selection line 122, and the gate of the initialization transistor 386 is connected to the initialization line 121.

  The detection drive circuit 54 in FIG. 1 includes a selection circuit 541 and an output circuit 543, and drives each detection circuit Q. The selection circuit 541 sequentially selects the detection circuits Q in units of rows within the unit period V defined by the synchronization signal SYNC, and performs the initialization operation, detection operation, and output operation on the N detection circuits Q in the selected row. To run. Each operation will be described in detail below.

  When the initialization operation starts, the selection circuit 541 controls the potential of the initialization line 121 in FIG. 2 to cause the initialization transistor 386 to transition to the on state. Therefore, the potential VG of the gate of the amplification transistor 382 is initialized to the potential VRS of the feeder line 16. When the initialization operation is performed, the selection transistor 384 is controlled to be in an off state.

  When the detection operation starts after execution of the initialization operation, the selection circuit 541 controls the potential of the initialization line 121 to shift the initialization transistor 386 to the off state. Since the selection transistor 384 continues to be in the off state from the initialization operation, the gate of the amplification transistor 382 is in an electrically floating state. Therefore, the potential VG of the gate of the amplification transistor 382 is variably set according to the photocurrent Ip (light reception amount) of the photo detector 36.

  When the output operation starts after the detection operation is performed, the selection circuit 541 controls the potential of the selection line 122 to shift the selection transistor 384 to the on state. Therefore, the detection signal Is having a current amount corresponding to the potential VG set in the immediately preceding detection operation (that is, a current amount corresponding to the presence / absence of the object to be detected) passes through the amplifying transistor 382 and the selection transistor 384 from the feeder line 16. And output to the detection line 14. The above operations are sequentially executed for each detection circuit Q in units of rows.

  The output circuit 543 in FIG. 1 generates the detection signal S from the detection signal IS output from the N detection circuits Q to the detection line 14 for each unit period V. The detection signal S is a voltage signal whose signal value (voltage value) is set in a time-sharing manner according to the amount of current of the detection signal IS generated by each detection circuit Q.

  The detection processing circuit 60 detects an object to be detected according to the detection signal S output from the output circuit 543. As shown in FIG. 3, the detection processing circuit 60 includes a data generation unit 62, an image change detection unit 64, a data update unit 66, a determination unit 68, and a storage circuit 70. As shown in FIG. 4, the data generation unit 62 sequentially detects detection data D (D [1], D [2], D [3],...) For each unit period V from the detection signal S generated by the output circuit 543. ...) is generated. Specifically, the data generation unit 62 sequentially A / D-converts the detection signal S into a digital detection value d (that is, a numerical value corresponding to the amount of current of the detection signal IS generated by each detection circuit Q), Detection data D is generated by dividing the detection value d for each unit period V defined by the synchronization signal SYNC.

  The detection data D generated by the above procedure is a set (M × N) of detection values d corresponding to the photocurrent Ip of each detection circuit Q within one unit period V. Therefore, when the detection object approaches (or touches) the display area A, each detection value d of the detection data D changes from the detection data D when the detection object does not exist. In addition, the wiring (control line 12, detection line 14) used for generating the detection data D and the elements of the detection circuit Q (particularly the light detector 36), and the wiring (scanning line, signal line) used for image display. ) And the elements of the pixel circuit P (particularly liquid crystal capacitors), the potential of each part of the detection circuit Q, the control line 12 and the detection line 14 depends on the image displayed in the display area A. (So-called crosstalk). Moreover, the emitted light (display light) from each pixel circuit P that displays an image reaches the light detector 36 of each detection circuit Q. Therefore, each detection value d of the detection data D also changes when the image displayed in the display area A changes.

  The storage circuit 70 sequentially stores the detection data D generated by the data generation unit 62. The detection data D is taken into the storage circuit 70 sequentially for each unit period V defined by the synchronization signal SYNC. Further, the storage circuit 70 stores reference data Dref (a set of M × N detection values d) to be compared with the detection data D for detecting the detection object.

  The image change detection unit 64 detects a change in the image displayed in the display area A. The image change detection unit 64 according to the first embodiment detects a change in the image in the display area A by referring to the change notification signal E supplied from the information processing apparatus 200. The change notification signal E is a signal for designating the start and end of image change. That is, assuming that the image GA changes to the image GB as illustrated in FIG. 4, the change notification signal E is the start point (image GA of the unit period V [4] in which the changed image GB is first displayed. Is designated as the start of the change of the image, and the end point of the unit period V where the image GB is first displayed is designated as the end of the change of the image. The image change detection unit 64 sets image change information (flag) F indicating the presence or absence of an image change according to the change notification signal E, and stores it in the storage circuit 70. Each time the image change detection unit 64 detects a change in the image, the data update unit 66 uses the reference data Dref stored in the storage circuit 70 as the detection data D generated after the change is completed (that is, after the change). Update to detection data D) affected by the image.

  The determination unit 68 in FIG. 3 sequentially determines the presence / absence of an object to be detected for each detection data D (for each unit period V) by comparing the detection data D stored in the storage circuit 70 with the reference data Dref. As shown in FIG. 3, the determination unit 68 includes a difference calculation unit 681 and an approach determination unit 683. The difference calculation unit 681 calculates difference data Ddif corresponding to the difference between the detection data D and the reference data Dref and stores it in the storage circuit 70. The difference data Ddif is a set (M × N) of difference values between each detection value d constituting the detection data D and each detection value d constituting the reference data Dref. That is, of the difference data Ddif, the difference value corresponding to the i-th and j-th column is the photocurrent Ip in the detection circuit Q in the i-th and j-th column when the detection data D is generated, and the reference data Dref. It becomes a numerical value corresponding to the difference from the photocurrent Ip in the detection circuit Q at the time of generation. Therefore, when the detection object approaches the display area A, the difference value corresponding to the detection circuit Q in the vicinity of the position where the detection object approaches in the difference data Ddif is detected from the detection circuit Q separated from the position of the detection object. It becomes a large numerical value compared with the difference value (zero) corresponding to.

  The approach determination unit 683 determines the presence or absence of an object to be detected according to the difference data Ddif calculated by the difference calculation unit 681. Specifically, the approach determination unit 683 has a number of difference values that exceed a predetermined threshold among a plurality of (M × N) difference values constituting the difference data Ddif (that is, each detection circuit when the detected object approaches). The area of the region where the photocurrent Ip of Q has changed is counted. Then, the approach determination unit 683 determines that the detected object has approached when the number of difference values exceeding the threshold exceeds a predetermined value, and the detected object has approached when the number is less than the predetermined value. Judge that there is no.

  FIG. 5 is a flowchart of specific operations of the detection processing circuit 60. When the processing of FIG. 5 is started, the image change detection unit 64 initializes the image change information F stored in the storage circuit 70 to a numerical value f0 which means that the image has not changed (step SA1). Next, the data generation unit 62 generates detection data D from the detection signal S output by the output circuit 543 and stores it in the storage circuit 70 as an initial value of the reference data Dref (step SA2). FIG. 4 illustrates a case where the detection data D [1] generated first is held as reference data Dref.

  The image change detection unit 64 executes image change information management (step SA3). The image change information management is a process for managing (changing or maintaining) the image change information F stored in the storage circuit 70 in accordance with the change notification signal E. In the image change information management in step SA3, the image change information F includes a numerical value f0 which means that the image has not changed, a numerical value f1 which means that the image is changing, and an image change. It is set to one of the numerical values f2 which means completion.

  FIG. 6 is a flowchart of image change information management in step SA3. First, the image change detection unit 64 determines the numerical value of the image change information F at the current stage (step SB1). When the image change information F is a numerical value f0 (no change), the image change detection unit 64 determines whether or not the start of image change is instructed by the change notification signal E supplied from the information processing apparatus 200 ( Step SB2). When the start of image change is instructed, the image change detection unit 64 updates the image change information F to a numerical value f1 (being changed) (step SB3), and ends the image change information management. If the start of image change is not instructed in step SB2, the image change detection unit 64 ends the image change information management while maintaining the image change information F at the numerical value f0 (no change).

  If it is determined in step SB1 that the image change information F is the numerical value f1 (being changed), the image change detection unit 64 has been instructed to end the image change by the change notification signal E supplied from the information processing apparatus 200. It is determined whether or not (step SB4). When the end of the image change is instructed, the image change detecting unit 64 updates the image change information F to a numerical value f2 (change complete) (step SB5), and ends the image change information management. If the end of the image change is not instructed in step SB4, the image change detection unit 64 ends the image change information management while maintaining the image change information F at the numerical value f1 (being changed).

  If it is determined in step SB1 that the image change information F is the numerical value f2 (change complete), the image change detection unit 64 updates the image change information F to the numerical value f0 (no change) (step SB6), and then the image. End change information management. That is, the image change information F is set to a numerical value f2 (change complete) in the unit period V immediately after the information processing apparatus 200 instructs the end of the image change.

  The above is the content of image change information management. When the image changes from the unit period V [4] as shown in FIG. 4 (GA → GB), the image change information F is displayed in the unit period V [4] immediately after the change notification signal E instructs the start of the change. Is set to a numerical value f1 (change in progress) (step SB3), and the image change information F is set to a numerical value f2 (change complete) in the unit period V [5] immediately after the change notification signal E instructs the end of the change. It is set (step SB5). In each unit period V after the unit period V [6], the image change information F is maintained at a numerical value f0 until the image changes again.

  When the image change information management in step SA3 is completed, the data generation unit 62 generates the next detection data D from the detection signal S and stores it in the storage circuit 70 (step SA4). Then, the image change detection unit 64 determines the numerical value of the image change information F stored in the storage circuit 70 (step SA5).

  When the image change information F is a numerical value f0 (no change), the determination unit 68 detects the detection data D (detection data D generated in the immediately preceding step SA4) and the reference data Dref stored in the storage circuit 70 at the present stage. To determine the presence or absence of an object to be detected. Specifically, the difference calculation unit 681 calculates the difference data Ddif from the detection data D and the reference data Dref (step SA6), and the approach determination unit 683 determines the detected object according to the difference data Ddif calculated in step SA6. The presence / absence and position are determined (step SA7). The result of the determination by the approach determination unit 683 is notified to the information processing apparatus 200 and used for various processes, for example. When the image change information F is a numerical value f0, the reference data Dref stored in the storage circuit 70 is not updated.

  When step SA7 is completed, the processing after step SA3 is repeated. For example, in FIG. 4, since the image change information F is set to a numerical value f0 in the unit period V [2] and the unit period V [3], the detection is performed while the reference data Dref is maintained as the detection data D [1]. Detection of the detection object using the data D [2] and detection of the detection object using the detection data D [3] are sequentially performed.

  If the image change information F is a numerical value f1 (being changed) in step SA5, detection of an object to be detected using the detection data D generated in the immediately preceding step SA4 is not executed, and the process proceeds to step SA3. . That is, the operation of the determination unit 68 (detection of an object to be detected) stops while the image displayed in the display area A is changing. For example, in FIG. 4, since the image change information F is set to the numerical value f1 in the unit period V [4], the detection of the detection object using the detection data D [4] of the unit period V [4] is not executed. .

  If the image change information F is the numerical value f2 (change complete) in step SA5, the data update unit 66 updates the reference data Dref stored in the storage circuit 70 (step SA8). That is, the data update unit 66 stores the detection data D generated in the immediately preceding step SA4 in the storage circuit 70 as the updated reference data Dref. For example, in FIG. 4, since the image change information F is set to a numerical value f2 in the unit period V [5], the reference data Dref in the storage circuit 70 is changed from the detection data D [1] in the unit period V [1] to the unit. The detection data D [5] of the period V [5] is updated.

  When the update of the reference data Dref in step SA8 is completed, detection of the detection object by the determination unit 68 is not executed, and the process proceeds to step SA3. In the image change information management of step SA3 executed immediately after step SA8, the image change information F is set to a numerical value f0 (no change) (step SB6). Therefore, in each unit period V after the unit period V [6] in FIG. 4, the detection data D (D [6], D [7],...) And the updated reference data Dref (detection data) in step SA8. D [5]) is detected in sequence (step SA6 and step SA7) in sequence.

  When the image of the display area A changes, each detection value d of the detection data D also changes. Therefore, in a configuration in which the reference data Dref is not updated, the difference between the detection data D after the change of the image and the reference data Dref (difference data Ddif) The number of difference values exceeding the threshold value) increases. Therefore, there is a possibility that the determination unit 68 erroneously detects the detected object immediately after the change of the image in the display area A, even though the detected object does not actually exist. In the first embodiment, when the image of the display area A changes, the reference data Dref is updated to the detection data D after the change of the image, so that erroneous detection of the detection object due to the change of the image can be prevented. There is an advantage. In addition, when the image change information F is the numerical value f1 or the numerical value f2 (that is, while the image in the display area A is changing), the detection of the detection object by the determination unit 68 is stopped, so that the image change Compared with the configuration in which the detection is performed, it is possible to prevent erroneous detection of the detected object with high accuracy.

  As a configuration for updating the reference data Dref, a configuration in which the reference data Dref is updated to the detection data D every time determination using the detection data D (hereinafter referred to as “proportional”) is also employed. However, since the reference data Dref is updated frequently (specifically, for each unit period V) under the proportionality, problems such as complicated operation of the detection processing circuit 60 and increase in power consumption occur. In the first embodiment, since the reference data Dref is updated only when the image displayed in the display area A changes, there is an advantage that the problem of proportionality is solved.

<B: Second Embodiment>
Next, a second embodiment of the present invention will be described. In the first embodiment, the configuration in which the image change detection unit 64 detects a change in an image using the change notification signal E supplied from the information processing apparatus 200 is exemplified. In the second embodiment, a change in the image is detected according to a change in the detection data D. In addition, about the element in which an effect | action and a function are equivalent to 1st Embodiment in each following form, the same code | symbol as the above is attached | subjected and each detailed description is abbreviate | omitted suitably.

  As described in the first embodiment, the detection data D (detection value d) varies depending on the content of the image displayed in the display area A. Therefore, the detection data D generated before the change of the image is different from the detection data D generated after the change of the image. Therefore, the image change detection unit 64 of the second embodiment detects the change in the image in the display area A by comparing the detection data D and the reference data Dref.

  FIG. 7 is a flowchart of the operation of the detection processing circuit 60. As shown in FIG. 7, in the second embodiment, step SC1 and step SC2 are executed instead of step SA3 and step SA4 in FIG. In step SC 1, the data generation unit 62 generates detection data D from the detection signal S and stores it in the storage circuit 70. In step SC2, the image change detection unit 64 performs image change detection. The image change detection is a process for determining whether or not the image displayed in the display area A has changed, and managing (changing or maintaining) the image change information F stored in the storage circuit 70 according to the determination result. is there. The image change information F is set to either a numerical value f0 that means that the image has not changed or a numerical value f1 that means that the image has changed.

  FIG. 8 is a flowchart of image change detection (step SC2). As shown in FIG. 8, the image change detection unit 64 calculates difference data Ddif from the detection data D generated in the immediately preceding step SC1 and the reference data Dref at the current stage (step SD1). Next, the image change detection unit 64 binarizes each difference value of the difference data Ddif calculated in step SD1 (step SD2), and calculates the number K of non-zero numerical values in the binarized difference data Ddif ( Step SD3). Since the detection data D (reference data Dref) is affected by the image in the display area A, the image displayed in the display area A when the reference data Dref is generated and the display area A when the detection data D is generated in step SC1. If the displayed image is different, the number K is a large number. Therefore, the number K can be used as a measure of the degree of change in the image displayed in the display area A.

  The image change detection unit 64 determines whether or not the number K calculated in step SD3 exceeds a predetermined threshold value Kth (step SD4). If the result of step SD4 is affirmative (K> Kth), it can be determined that the image in the display area A has changed, so the image change detection unit 64 sets the image change information F to a numerical value f1 (changed) ( Step SD5). On the other hand, if the result of step SD4 is negative (K ≦ Kth), it can be determined that the image in the display area A has not changed, so the image change detection unit 64 sets the image change information F to the numerical value f0 (no change). (Step SD6). The threshold value Kth is selected statistically or experimentally so as to exceed the number K calculated when the detected object approaches the display area A. For example, the threshold value Kth is set to a numerical value within a range from 0.02% to 10% of the total number (M × N) of the detection circuits Q. Execution of step SD5 or step SD6 ends the image change detection of FIG.

  As shown in FIG. 7, when the image change information F is a numerical value f0, as in the first embodiment, the determination unit 68 determines the presence or absence of an object to be detected (steps SA6 and SA7). For example, in FIG. 9, since the image change information F is set to a numerical value f0 in the unit period V [2] and the unit period V [3], the detection of the detected object using the detection data D [2] and the detection data are performed. Detection of an object to be detected using D [3] is sequentially performed.

  On the other hand, when the image change information F is a numerical value f1 (changed), the data update unit 66 stores the detection data D generated in the immediately preceding step SC1 as new reference data Dref in the storage circuit 70 (step). SA8). For example, as shown in FIG. 9, assuming that the image changes in the unit period V [4], the detection data D [4] generated in the unit period V [4] is the past detection data D [1. ] To D [3], the image change information F is updated to a numerical value f1 in the unit period V [4]. Therefore, the reference data Dref in the storage circuit 70 is updated from the detection data D [1] in the unit period V [1] to the detection data D [4]. As in the first embodiment, in the unit period V in which the image change information F is set to the numerical value f1, the determination unit 68 stops detecting the detection object.

  Assuming a case in which an image GB common to the unit period V [4] is displayed in the display area A in the unit period V [5], the detection data D [5] and the reference data Dref (detection data D [4]) Is substantially the same (K ≦ Kth), the image change information F is updated from the numerical value f1 to the numerical value f0 (no change) (step SD6). Therefore, the detection of the detection object is executed in each unit period V (V [5], V [6], V [7],...) After the unit period V [5].

  In the above embodiment, the same effect as that of the first embodiment is realized. In the second embodiment, the change notification signal E is not necessary because the change in the image in the display area A is detected according to the change in the detection data D. Therefore, there is an advantage that it is not necessary to install a special function for generating and transmitting the change notification signal E in the information processing apparatus 200.

<C: Modification>
Each of the above forms is variously modified. Specific modes of deformation for each form are exemplified below. Note that two or more aspects arbitrarily selected from the following examples are appropriately combined.

(1) Modification 1
The method by which the image change detection unit 64 detects a change in the image is arbitrary. For example, a configuration for detecting a change in an image by comparing each image data G sequentially supplied from the information processing apparatus 200, or a change in an image by detecting an operation on an operator for instructing the change in the image. A configuration is also employed in which the signal is detected.

  In the second embodiment, the change in the image is detected by comparing the detection data D with the reference data Dref. However, the object to be compared with the detection data D for detecting the change in the image is the reference data Dref. It is not limited. For example, a configuration in which a change in an image is detected by comparing the detection data D of each unit period V with the detection data D of a unit period V immediately before (for example, immediately before) a predetermined number from the unit period V is also employed. That is, the image change detection unit 64 in the second embodiment is included as an element that detects a change in an image according to a difference between a plurality of detection data generated at different points in time.

(2) Modification 2
In each of the above embodiments, the detection data D is generated for each unit period V in which an image is displayed in the display area A, but the relationship between the display period of the image and the generation period of the detection data D is arbitrary. For example, a configuration in which the detection data D is generated using a set of a plurality of unit periods V as a unit is also employed.

(3) Modification 3
In each of the above embodiments, the change notification signal E indicates the start point and the end point of the first unit period V (the unit period V [4] in FIG. 4) after the image change, but the change notification signal E indicates. The period during the image change is not limited to one unit period V. For example, a configuration in which the change notification signal E indicates a time point a predetermined length before the start point of the first unit period V after the image change as the start point of the image change, or an end point of the first unit period V after the image change A configuration is also adopted in which a point in time when a predetermined length has elapsed from the start point is designated as the end point of the image change. A configuration in which the change notification signal E indicates the start point of the first unit period V and the end point of the last unit period V among the plurality of unit periods V including the first unit period V after the image change is also preferable. is there.

(4) Modification 4
A display element (electro-optical element) used for displaying an image is not limited to a liquid crystal capacitor. About the display element applied to the display device of the present invention, it is driven by the distinction between the self-luminous type that emits light itself and the non-luminous type (for example, liquid crystal capacitor) that changes the transmittance and reflectance of external light, or by supplying current There is no distinction between the current driven type and the voltage driven type driven by application of an electric field (voltage). For example, an organic EL element, an inorganic EL element, a field electron emission element (FE (Field-Emission) element), a surface conduction electron emission element (SE (Surface conduction Electron emitter) element), a ballistic electron emission element (BS) The present invention is applied to a display device using various display elements such as an Emitting element, an LED (Light Emitting Diode) element, an electrophoretic element, and an electrochromic element. That is, the display element is included as an electro-optical element whose optical characteristics (gradation) change according to an electrical action (supply of current or application of voltage).

<D: Application example>
Next, an electronic device using the display device 100 according to each of the above aspects will be described. FIG. 10 is a perspective view illustrating a configuration of a mobile personal computer that employs the display device 100. The personal computer 2000 includes a display device 100 that displays various images, and a main body 2010 on which a power switch 2001 and a keyboard 2002 are installed.

  FIG. 11 is a perspective view illustrating a configuration of a mobile phone to which the display device 100 is applied. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and a display device 100 that displays various images. By operating the scroll button 3002, the screen displayed on the display device 100 is scrolled.

  FIG. 12 is a perspective view showing the configuration of a personal digital assistant (PDA) to which the display device 100 is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and a display device 100 that displays various images. When the power switch 4002 is operated, various information such as an address book and a schedule book are displayed on the display device 100.

  Note that electronic devices to which the display device according to the present invention is applied include, in addition to the devices illustrated in FIGS. 10 to 12, a digital still camera, a television, a video camera, a car navigation device, a pager, an electronic notebook, electronic paper, Examples include calculators, word processors, workstations, videophones, POS terminals, printers, scanners, copiers, and video players.

DESCRIPTION OF SYMBOLS 100 ... Display apparatus, 10 ... Driven element part, 12 ... Control line, 14 ... Detection line, 16 ... Feeding line, P ... Pixel circuit, Q ... Detection circuit, 36 ... Photodetector , 38... Circuit section, 382... Amplification transistor, 384... Selection transistor, 386... Initialization transistor, 52... Display drive circuit, 54. ... Output circuit 56... Timing control circuit 60... Detection processing circuit 62... Data generation unit 64 64 Image change detection unit 66. Calculation unit, 683... Proximity determination unit, 70.

Claims (3)

A plurality of pixel circuits for displaying an image in the display area;
A plurality of detection circuits arranged in the display area, each of which outputs a detection signal corresponding to the amount of light received by the light detector;
Data generation means for generating detection data from detection signals output by the plurality of detection circuits;
Storage means for storing reference data to be compared with the detection data;
Determination means for determining the presence or absence of an object to be detected by comparing the detection data and the reference data;
Image change detection means for detecting a change in an image displayed in the display area;
A display device comprising: a data updating unit that updates reference data used for determination by the determination unit to detection data after the change when the image change detection unit detects a change in the image.   An electronic apparatus comprising the display device according to claim 1. A display device driving method comprising: a plurality of pixel circuits that display an image in a display area; and a plurality of detection circuits that are arranged in the display area and each output a detection signal corresponding to the amount of light received by a photodetector. Because
Generating detection data from detection signals output from the plurality of detection circuits;
Determining the presence or absence of an object to be detected by comparing the detected data with reference data;
When the image displayed on the display area changes, the reference data used for the determination is updated to the detection data after the change.

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