JP2010182063A - Display, electronic device, and method of driving display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent erroneous detection 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 presence/absence of detected objects. 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 detected objects sequentially by comparison between the detection data D and reference data Dref. An image change detecting section 64 detects the change of images displayed in the display area A. A data updating section 66 updates the reference data Dref stored by 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 problems, a display device according to the present invention includes a plurality of pixel circuits that display an image in a display area, and the presence or absence (approach or contact) of an object to be detected that is arranged in the display area. A plurality of detection circuits each outputting a detection signal; data generation means for sequentially generating detection data from detection signals output by the plurality of detection circuits; and storage means for storing reference data to be compared with the detection data; A determination means for sequentially determining the presence or absence of an object to be detected by comparing detection data and reference data, an image change detection means for detecting a change in an image displayed in a display area, and an image change detection means for detecting a change in an image. Data detection means for updating the reference data used for determination by the determination means to the detected data after the change when detected. 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.

  The principle of operation of the detection circuit and the circuit configuration are arbitrary in the present invention. For example, each of the plurality of detection circuits includes a detection capacitor whose capacitance value changes in accordance with the presence or absence of the detection object, and outputs a detection signal according to the capacitance value of the detection capacitor. Specifically, each of the plurality of detection circuits includes a reference capacitor interposed between the detection capacitor and the initialization line, an amplification transistor having a gate connected between the detection capacitor and the reference capacitor, and an amplification transistor Including an initialization transistor interposed between the gate and the power supply line and having the gate connected to the initialization line, and is initialized from a potential for controlling the initialization transistor to an on state to a potential for controlling the initialization transistor to an off state. A detection signal corresponding to the potential of the gate of the amplification transistor when the potential of the activation line is changed is output. In the above embodiment, since the gate potential of the amplification transistor changes with the operation of controlling the initialization transistor in the off state, the configuration in which the potential of the gate of the amplification transistor is changed by an operation separate from the control of the initialization transistor; In comparison, there is an advantage that driving of the detection circuit is simplified. Further, it is also preferable that each of the plurality of detection circuits includes a light detector whose amount of received light changes depending on the presence or absence of an object to be detected, and outputs a detection signal corresponding to the amount of light received by the light detector.

  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 fragmentary sectional view of a display. 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. FIG. 6 is a circuit diagram of a detection circuit according to a third embodiment. 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 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 the liquid crystal capacitor 27 of FIG. The liquid crystal capacitor 27 includes a pixel electrode 22 formed for each pixel circuit P on the surface of the substrate 21, a counter electrode 24 formed on the entire surface of the substrate 23 disposed on the observation side of the substrate 21, and the substrate 21 and the substrate The liquid crystal 25 is sealed in a gap with the liquid crystal 23.

  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. 5).

  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 capacitor 27 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. 3 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. 3, the detection circuit Q includes a detection capacitor 32 and a circuit unit 34. As shown in FIG. 2, the detection capacitor 32 is arranged in the gap between the substrate 21 and the substrate 23 together with the liquid crystal capacitor 27 (in-cell method). Specifically, the detection capacitor 32 is a capacitor that includes an electrode 26 on the surface of the substrate 21, a counter electrode 24 on the surface of the substrate 23, and a liquid crystal 25 between both electrodes. When the substrate 23 is deformed by an external force acting on the object to be detected, the distance between the electrode 26 and the counter electrode 24 changes. Therefore, the detection capacitor 32 functions as a variable capacitor whose capacitance value cX changes depending on whether or not the object to be detected is in contact with the substrate 23.

  The circuit unit 34 in FIG. 3 generates a detection signal Is corresponding to the capacitance value cX of the detection capacitor 32 and outputs it to the detection line 14. As shown in FIG. 3, the circuit unit 34 includes an amplification transistor 342, a selection transistor 344, an initialization transistor 346, and a reference capacitor 348. The conductivity type of each transistor in the circuit unit 34 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 342 and the selection transistor 344 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 342 is connected to the electrode 26 of the detection capacitor 32, and the gate of the selection transistor 344 is connected to the selection line 122. The initialization transistor 346 is interposed between the gate of the amplification transistor 342 and the power supply line 16 and controls electrical connection (conduction / non-conduction) between the two. The gate of the initialization transistor 346 is connected to the initialization line 121. The reference capacitor 348 is interposed between the initialization line 121 and the gate of the amplification transistor 342.

  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 a plurality of detection circuits Q in units of rows within a unit period V defined by the synchronization signal SYNC, and detects an initialization operation, a detection operation, and an output operation for N selected rows. The circuit Q is executed. Each operation will be described in detail below.

  When the initialization operation starts, the selection circuit 541 shifts the initialization transistor 346 to the on state by supplying the selection potential VH to the initialization line 121 in FIG. Therefore, the potential VG of the gate of the amplification transistor 342 (the electrode 26 of the detection capacitor 32) is initialized to the potential VRS of the feeder line 16.

When the detection operation starts after execution of the initialization operation, the selection circuit 541 changes the potential of the initialization line 121 from the selection potential VH to the non-selection potential VL, thereby causing the initialization transistor 346 to transition to the off state. When the initialization transistor 346 transitions to the OFF state, the gate of the amplification transistor 342 enters an electrically floating state. Therefore, the potential VG of the gate of the amplification transistor 342 is interlocked with the change in the potential of the initialization line 121 (VH → VL). Also changes. The change amount ΔVG of the potential VG is expressed by the following equation (1): the change amount (VH → VL) of the potential of the initialization line 121 is expressed by the reference capacitor 348 (capacitance value cR) and the detection capacitor 32 (capacitance). This corresponds to the voltage divided according to the capacity ratio with the value cX). That is, the potential VG of the gate of the amplifying transistor 342 is variably set according to the capacitance value cX of the detection capacitor 32 (that is, depending on whether or not the object to be detected contacts the substrate 23). In Equation (1), the gate capacitance of the amplification transistor 342 is omitted for convenience.
ΔVG = (VH−VL) · cR / (cR + cX) (1)

  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 344 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 an object to be detected) passes through the amplification transistor 342 and the selection transistor 344 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. 4, 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. 5, the data generation unit 62 sequentially detects detection data D (D [1], D [2], D [3],...) From the detection signal S generated by the output circuit 543 for each unit period V. ...) 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 capacitance value cX of the detection capacitor 32 of each detection circuit Q within one unit period V. Therefore, when the substrate 23 is pressed by the contact of the detection object, each detection value d of the detection data D changes from the detection data D when the detection object is not in contact with the substrate 23. In addition, wiring (control line 12, detection line 14) used for generation of detection data D and elements of detection circuit Q (particularly detection capacitor 32), and wiring (scanning line, signal line) used for image display. Since the capacitance is parasitic between the pixel circuit P and the elements of the pixel circuit P (particularly, the liquid crystal capacitor 27), 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). 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. 5, the change notification signal E is the start point of the unit period V [4] in which the changed image GB is first displayed (the image GA 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.

  4 determines the presence / absence of an object to be detected sequentially 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. 4, 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, the difference value corresponding to the i-th and j-th column of the difference data Ddif is the capacitance value cX of the detection capacitor 32 in the detection circuit Q of the i-th and j-th column when the detection data D is generated. The numerical value corresponds to the difference from the capacitance value cX of the detection capacitor 32 in the detection circuit Q when the reference data Dref is generated. Therefore, when the substrate 23 is pressed by the contact of the detected object, the difference value corresponding to the detection circuit Q in the vicinity of the position where the detected object is pressed in the difference data Ddif is detected from the detection circuit Q separated from the pressed position. 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, the detection capacity 32 by pressing with the detected object). The area of the region in which the capacitance value cX of the above has changed is counted. Then, the approach determination unit 683 determines that the detected object is in contact with the substrate 23 when the number of difference values exceeding the threshold exceeds a predetermined value, and the detected object is determined when the number falls below the predetermined value. It is determined that there is no contact.

  FIG. 6 is a flowchart of specific operations of the detection processing circuit 60. When the processing of FIG. 6 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. 5 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. 7 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. 5 (GA → GB), the image change information F 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. 5, in the unit period V [2] and the unit period V [3], since the image change information F is set to the numerical value f0, 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. 5, 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. 5, 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. 5, the detection data D (D [6], D [7],...) And the reference data Dref (detection data) updated 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 is not actually in contact with the substrate 23. 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. 8 is a flowchart of the operation of the detection processing circuit 60. As shown in FIG. 8, 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. 9 is a flowchart of image change detection (step SC2). As shown in FIG. 9, 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 object to be detected comes into contact with the substrate 23. 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. 8, 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. 10, 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. 10, 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: Third Embodiment>
A third embodiment of the present invention will be described. In the first embodiment and the second embodiment, the change in the capacitance value cX of the detection capacitor 32 in each detection circuit Q is used for detection of an object to be detected (capacitance method). In the third embodiment, An object to be detected is detected according to the amount of light arriving at each detection circuit R (light detection method).

  In the display area A of the display device 100 according to the third embodiment, the detection circuits R of FIG. 11 are arranged in a matrix instead of the detection circuit Q of FIG. As shown in FIG. 11, the detection circuit R 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. Since the amount of light received by the light detector 36 changes depending on whether or not the object to be detected exists (whether it is hidden by the shadow of the object to be detected), the current amount of the photocurrent Ip depends on the presence or absence of the object to be detected. Change.

  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. 11, the circuit unit 38 includes an amplification transistor 382, a selection transistor 384, and an initialization transistor 386. The amplification transistor 382 and the selection transistor 384 are connected in series between the power supply line 16 (potential VRS) and the detection line 14. 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 selection circuit 541 sequentially selects the detection circuits R 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 R in the selected row. To run. When the initialization operation starts, the selection circuit 541 controls the potential of the initialization line 121 to shift the initialization transistor 386 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, a detection signal Is having a current amount corresponding to the potential VG set in the detection operation is output from the feeder line 16 to the detection line 14 via the amplification transistor 382 and the selection transistor 384. The above operation is sequentially executed for each row of each detection circuit R. The operation of generating the detection data D from each detection signal Is is the same as in the first embodiment.

  Since the current amount of the photocurrent Ip (the potential VG of the gate of the amplification transistor 382) changes depending on whether or not the detection object exists, the detection signal IS is set to a current amount corresponding to the presence or absence of the detection object. Is done. Accordingly, the detection data D generated by the data generation unit 62 is data (a set of M × N detection values d) indicating the presence / absence and position of an object to be detected, as in the first embodiment.

  The operation of the detection processing circuit 60 is the same as that of the first embodiment or the second embodiment. For the detection of the image change by the image change detection unit 64, for example, the method of the first embodiment using the change notification signal E supplied from the information processing apparatus 200, or the second embodiment using the change of the detection data D is used. The method of the form is arbitrarily adopted.

  In the third embodiment, since the detection data D is generated according to the amount of light received by the light detector 36, there is an advantage that detection is possible even when the detection object does not contact the display device 100. In the configuration using the light detector 36 in the detection circuit R as in the third embodiment, an element for displaying an image (wiring or pixel circuit P) and an element for detecting an object to be detected (wiring or detection circuit R). In addition to the parasitic capacitance between the detection data D and the light emitted from each pixel circuit P irradiated to the light detection body 36, the detection data D changes depending on the content of the image. Therefore, in the configuration using the light detection method for detecting the detection object, the detection object is erroneously detected due to the change of the image, as compared with other detection methods (for example, the capacitance method of the first embodiment). There is a situation that there is a high possibility of. In consideration of the above circumstances, the configuration of the present invention that can prevent erroneous detection of an object to be detected by updating the reference data Dref is particularly suitable for a display device that uses a light detection method as in the third embodiment.

<D: 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 capacitance method of the first embodiment and the light detection method of the third embodiment are exemplifications, and any known technique (for example, a resistance film method, a surface acoustic wave method, or an electromagnetic induction method) is arbitrarily used for detecting an object to be detected. Adopted. That is, the detection circuit according to the present invention is included as an element that generates a detection signal according to the presence or absence of an object to be detected, and the principle of detection signal generation and the circuit configuration are not questioned. Further, the structural relationship between the pixel circuit P and the detection circuit (Q, R) is also arbitrarily changed. For example, a configuration in which the pixel circuit P and the detection circuit (Q, R) are separately formed is also employed. Specifically, a display body on which a plurality of pixel circuits P are formed (for example, a liquid crystal panel including the substrate 21 and the substrate 23 in FIG. 2), a detection body on which a plurality of detection circuits (Q, R) are formed, and Is formed separately, and a configuration in which the detection body is arranged on the observation side of the display body is also employed.

(2) Modification 2
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.

(3) Modification 3
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.

(4) Modification 4
In each of the above forms, 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. 5) 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.

(5) Modification 5
A display element (electro-optical element) used for displaying an image is not limited to the liquid crystal capacitor 27. With respect to the display element applied to the display device of the present invention, by distinguishing between a self-luminous type that emits light itself and a non-luminous type that changes the transmittance and reflectance of external light (for example, liquid crystal capacitor 27), A distinction is not made between the driven 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).

<E: Application example>
Next, an electronic device using the display device 100 according to each of the above aspects will be described. FIG. 12 is a perspective view showing the 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. 13 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. 14 is a perspective view illustrating a 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. 12 to 14, digital still cameras, televisions, video cameras, car navigation devices, pagers, electronic notebooks, electronic papers, A calculator, a word processor, a workstation, a video phone, a POS terminal, a printer, a scanner, a copying machine, a video player, and the like can be given.

DESCRIPTION OF SYMBOLS 100 ... Display apparatus, 10 ... Driven element part, 12 ... Control line, 14 ... Detection line, 16 ... Feeding line, P ... Pixel circuit, Q, R ... Detection circuit, 32 ... Detection Capacitor 36... Photodetector 34, 38... Circuit unit 342 382... Amplifying transistor 344 384... Selection transistor 346 386. ... Display drive circuit, 54 ... Detection drive circuit, 541 ... Selection circuit, 543 ... Output circuit, 56 ... Timing control circuit, 60 ... Detection processing circuit, 62 ... Data generation unit, 64 ... Image change detection unit, 66... Data update unit, 68... Determination unit, 681... Difference calculation unit, 683.

Claims (8)

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 according to the presence or absence of an object to be detected;
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. The display device according to claim 1, wherein the data update unit stops updating reference data used for determination by the determination unit when the image change detection unit does not detect a change in the image. The display device according to claim 1, wherein the determination unit stops determination during detection of an image change by the image change detection unit. 4. The detection circuit according to claim 1, wherein each of the plurality of detection circuits includes a detection capacitor whose capacitance value changes according to the presence or absence of an object to be detected, and outputs a detection signal according to the capacitance value of the detection capacitor. Display device. Each of the plurality of detection circuits includes:
A reference capacitor interposed between the detection capacitor and the initialization line;
An amplification transistor having a gate connected between the detection capacitor and the reference capacitor;
An initialization transistor having a gate connected to the initialization line interposed between a gate of the amplification transistor and a power supply line,
The detection signal corresponding to the potential of the gate of the amplification transistor when the potential of the initialization line is changed from a potential for controlling the initialization transistor to an on state to a potential for controlling the initialization transistor to an off state. The display device according to claim 4 which outputs. The display device according to claim 1, wherein the image change detection unit detects a change in the image by a notification from an information processing device that designates an image displayed in the display area.   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 presence or absence of an object to be detected. There,
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.

Images