Display device and driving method thereof

Abstract

The present invention provides a display device and a driving method thereof, comprising: a pixel array (18); a plurality of common electrodes (22) arranged on the pixel array (18) for electrostatic capacitive touch detection; a common electrode driver (126) for supplying a voltage for display to the plurality of common electrodes (22) during display, and supplying a driving signal for touch detection to the plurality of common electrodes (22) during touch detection; a plurality of source lines (44) connecting the columns of the pixel array; a source amplifier (118) for supplying image signals to the plurality of source lines (44); a plurality of gate lines (46) connecting the rows of the pixel array; a gate driver (102) for sequentially supplying scanning signals to the plurality of gate lines during display, and supplying a signal with the same phase as the driving signal to the plurality of gate lines during touch detection; and a switch (148) connected between the plurality of source lines and the plurality of common electrodes, and for conducting the source lines with the common electrodes during touch detection.

Description

[0001] This application is a divisional application of a patent application with an application date of July 24, 2021, application number 201710609289.0, and invention name “Display device and driving method thereof”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application is based upon and claims the benefit of priority from Japanese patent application No. 2016-145603, filed on Jul. 25, 2016, the entire contents of which are incorporated herein by reference. Technical Field

[0004] Embodiments of the present invention relate to a display device including a touch detection function and a driving method thereof. Background Art

[0005] In recent years, the display devices of portable electronic devices such as smart phones or tablet computers sometimes include a so-called touch detection function that detects the contact or proximity of a conductor such as a human finger or a touch pen (hereinafter, contact or proximity will be collectively referred to as touch). This electronic device can accept operations on the electronic device by, for example, displaying a menu image containing multiple icons on the screen and determining which icon is touched. Therefore, the user can operate the electronic device without using an input device such as a keyboard, mouse or keypad. As a touch detection method, there are several methods including optical, resistive, and electrostatic capacitive, but electrostatic capacitive methods with a relatively simple structure and low power consumption are mostly used. The electrostatic capacitive touch sensor detects touch by using the property that the electrostatic capacitance of the electrode changes due to the presence of a conductor (when the conductor approaches, the value of the electrostatic capacitance increases).

[0006] A touch panel including such a touch sensor can also be externally connected to the screen of a display device, but in recent years it has been mostly assembled in a display device. In a display device assembled with a touch panel, when thinning is promoted, the electrodes of the touch sensor are close to various wirings used to display and drive the display device, or the wirings are close to each other, and parasitic capacitance is generated between them. In an electrostatic capacitive touch sensor, when parasitic capacitance is generated between the driving electrode and the wiring, the waveform of the driving signal is degraded, the transmission of the driving signal is delayed, the accuracy of touch detection is reduced, or the detection time is prolonged. Therefore, there is a problem that electrostatic capacitive touch sensors are easily affected by parasitic capacitance. Summary of the invention

[0007] An object of the present invention is to provide a display device including an electrostatic capacitance touch detection function that is not easily affected by parasitic capacitance, and a driving method thereof.

[0008] According to an embodiment, a display device includes: a pixel array; a plurality of common electrodes arranged on the pixel array for electrostatic capacitive touch detection; a common electrode driver, which supplies a voltage for display to the plurality of common electrodes during display, and supplies a drive signal for touch detection to the plurality of common electrodes during touch detection; a plurality of source lines connected to pixels in each column of the pixel array; a source amplifier, which supplies image signals to the plurality of source lines; a plurality of gate lines connected to pixels in each row of the pixel array; a gate driver, which sequentially supplies scan signals to the plurality of gate lines during display, and supplies a signal with the same phase as the drive signal to the plurality of gate lines during touch detection; and a switch, which is connected between the plurality of source lines and the plurality of common electrodes, and conducts the plurality of source lines with the plurality of common electrodes during touch detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view showing a schematic structure of an example of a display device with a touch detection function according to an embodiment.

[0010] Figure 2 This is a circuit diagram of an example of a pixel array.

[0011] Figure 3 It is a cross-sectional view schematically showing the structure of an example of a display device.

[0012] Figure 4 : is a diagram showing the principle of mutual induction touch detection.

[0013] Figure 5 This is a diagram showing an example of the arrangement of the display period and the touch detection period in one frame period.

[0014] Fig. 6A This is a diagram showing the principle of self-inductive touch detection.

[0015] Figure 6B This is a diagram showing the principle of self-inductive touch detection.

[0016] Fig. 7A This is a diagram showing the principle of self-inductive touch detection.

[0017] Figure 7B This is a diagram showing the principle of self-inductive touch detection.

[0018] Fig. 8A This is a diagram showing an example of a self-inductive touch detection circuit.

[0019] Figure 8B This is a diagram showing an example of a self-inductive touch detection circuit.

[0020] Fig. 9 It means in Fig. 8A and Figure 8B Graphs showing an example of a graph showing a relationship between capacitance Cx and voltage Vx and a graph showing a relationship between capacitance Cc and voltage Vc.

[0021] Fig.10 This is a diagram showing an example of the arrangement of the display period and the touch detection period in one frame period of the self-inductive type of simultaneous driving.

[0022] Fig.11 This is a block diagram showing an example of a schematic electrical configuration of a display device.

[0023] Fig.12 This is a block diagram showing a configuration example of a display control device.

[0024] Fig.13 This is a block diagram showing a configuration example of a portion related to protection driving of gate lines in a panel control signal generating circuit.

[0025] Fig.14 It is a timing diagram showing the protection drive of the gate line.

[0026] Fig.15 This is a circuit diagram showing a configuration example of a portion related to generation of a selection signal of a selection switch in a panel control signal generation circuit.

[0027] Fig.16 This is a timing diagram showing the selection operation of the selection switch.

[0028] Fig.17 1 is a circuit diagram showing an example of a selection signal generating circuit of a selection switch in a panel control signal generating circuit according to the second embodiment.

[0029] Fig.18 1 is a timing chart showing protection driving of the selection signal line of the selection switch according to the second embodiment.

[0030] Fig.19 1 is a circuit diagram showing an example of a selection signal generating circuit of a selection switch in a panel control signal generating circuit according to the third embodiment.

[0031] Fig. 20 1 is a timing chart showing protection driving of the selection signal line of the selection switch according to the third embodiment.

[0032] Fig.21A It is a diagram for explaining protection driving of the output of the source amplifier according to the fourth embodiment.

[0033] Fig.21B It is a diagram for explaining protection driving of the output of the source amplifier according to the fourth embodiment.

[0034] Fig. 21CIt is a diagram for explaining protection driving of the output of the source amplifier according to the fourth embodiment.

[0035] Fig.21D It is a diagram for explaining protection driving of the output of the source amplifier according to the fourth embodiment.

[0036] Fig. 22 1 is a timing chart showing protection driving of the output of the source amplifier according to the fourth embodiment.

[0037] Fig.23 It is a diagram for explaining protection driving of the output of the source amplifier according to the fifth embodiment.

[0038] Fig.24 It is a diagram for explaining protection driving of the output of the source amplifier according to the sixth embodiment.

[0039] Fig.25 1 is a timing chart showing protection driving of the output of the source amplifier according to the sixth embodiment.

[0040] Fig.26 It is a diagram for explaining the protection drive according to the seventh embodiment.

[0041] Fig. 27 This is a block diagram showing a configuration example of a portion related to protection driving of gate lines in a panel control signal generating circuit according to an eighth embodiment.

[0042] Fig.28 4 is a signal waveform diagram of the power line according to the eighth embodiment. DETAILED DESCRIPTION

[0043] Hereinafter, embodiments will be described in detail with reference to the drawings.

[0044] Disclosure is only an example after all, and disclosure is not limited by the contents described in the following embodiments. Deformations that can be easily thought of by a person skilled in the art are of course included in the scope of disclosure. In order to make the description clearer, in the drawings, the dimensions, shapes, etc. of each part are sometimes schematically represented after the actual embodiments are changed. In multiple drawings, the same reference numerals are sometimes attached to corresponding elements and detailed descriptions are omitted.

[0045] [First Embodiment (Schematic Configuration)]

[0046] Figure 1This is a three-dimensional diagram showing an overall schematic configuration example of an example of a display device with a touch detection function according to an embodiment. The display device includes: a display panel having a touch detection mechanism, a drive circuit thereof, and a control circuit thereof. As a display panel, a display panel using liquid crystal and a display panel using organic EL can be used, but this specification describes a display panel using liquid crystal. The liquid crystal display panel includes a pixel substrate that forms pixels of TFT (Thin Film Transistor).

[0047] "Touch detection" not only means that objects such as human fingers or touch pens are in contact with the display panel, but also means that it is detected that the object has approached the display panel. "Integrated" means that the touch sensor is not externally connected to the display panel, but the touch sensor is built into the display panel. Built-in includes: In-cell type in which a touch sensor is set on a pixel substrate; and On-cell type in which a touch sensor is set between a glass substrate forming a color filter and a polarizing plate. The In-cell touch sensor is explained by an embodiment, but the present invention can also be implemented by an On-cell touch sensor.

[0048] The display panel includes a transparent first substrate such as glass or resin (such as Figure 2 As shown, the pixels are formed in a matrix, so it is also called a pixel substrate) 12; a transparent second substrate (also called a counter substrate) 14 of glass, resin, etc. arranged opposite to the first substrate 12; and a liquid crystal layer (not shown) formed between the first substrate 12 and the second substrate 14. The display panel can be observed from the second substrate 14 side. Therefore, the second substrate 14 is sometimes called the upper substrate, and the first substrate 12 is called the lower substrate.

[0049] The display panel is in the shape of a rectangular flat plate, with the direction along the short side being the X direction and the direction along the long side being the Y direction. The first substrate 12 and the second substrate 14 have the same short side dimensions, but different long side dimensions, with the first substrate 12 being longer than the second substrate 14. One end of the long side of the first substrate 12 is aligned with one end of the long side of the second substrate 14, so the other end of the long side of the first substrate 12 is extended from the other end of the long side of the second substrate 14. A display control device 16 for driving the display panel for image display is installed on the extended portion of the first substrate 12 that protrudes further in the Y direction than the end of the second substrate 14 along the X direction. The display control device 16 can be implemented as an IC (Integrated Circuit), and when implemented as an IC, it is also called a display controller IC.

[0050] A pixel array 18 of TFT is formed in the display area (or active area) in the center of the display panel. The touch panel 20 is integrated with the pixel array 18. The touch panel 20 includes: a plurality of driving electrodes (driving electrodes for touch detection, but also driving electrodes for display driving, so they are hereinafter referred to as common electrodes) 22-1, 22-2, ... (in the first substrate 12) Figure 4 etc.) (sometimes also collectively referred to as 22); and a plurality of detection electrodes 24 for touch detection provided on the second substrate 14. The detection electrodes 24 and the common electrode 22 are formed of transparent electrode materials such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) so as not to cause obstacles to the display.

[0051] Electrostatic capacitive touch sensors can be divided into mutual inductance (mutual capacitance) type and self-inductance (self-capacitance) type. Either method is provided with a pair of electrodes sandwiching a dielectric. In the mutual inductance type, when a driving pulse is supplied to one electrode (called a common electrode), an electric field is generated between the common electrode and the other electrode (called a detection electrode). At this time, when a conductor such as a user's finger is in a touch state relative to the touch panel, an electric field is also generated between the conductor and the common electrode, and the electric field generated between the common electrode and the detection electrode is reduced, and the amount of charge between the common electrode and the detection electrode is reduced. The touch position is detected by detecting the reduction in the amount of charge with the help of the detection electrode.

[0052] In the self-inductance type, only one of the common electrode or the detection electrode is used. For example, when only the common electrode is used, there is a parasitic capacitance between the common electrode and the ground voltage. When a conductor touches the vicinity of the common electrode, an electric field is generated between the common electrode and the conductor. Due to the proximity of the conductor, the capacitance connected to the common electrode and the ground voltage increases, and the amount of charge stored between the common electrode and the ground voltage changes. The touch position is detected by detecting the decrease in the amount of charge with the help of the common electrode. The first embodiment describes an example of the self-inductance type, but this embodiment can also be implemented by a mutual inductance touch sensor.

[0053] A host device 26 is provided outside the display device. The display device and the host device 26 are connected via two flexible wiring substrates 28 and 32. The host device 26 is connected to the first substrate 12 and the second substrate 14 via the flexible wiring substrate 28. A touch detection device 34 for controlling the touch panel 20 is arranged on the flexible wiring substrate 28. The touch detection device 34 can be implemented as an IC, and when implemented as an IC, it is also called a touch controller IC.

[0054] The display control device 16 and the touch detection device 34 cooperate with each other in operation timing and are electrically connected to each other through a timing pulse, etc. The display control device 16 and the touch detection device 34 are not separate IC chips, but may be configured as the same IC chip.

[0055] A backlight unit 36 ​​is provided as a lighting device for illuminating the display panel on the back side of the first substrate 12 (i.e., the back side of the display panel). The host device 26 is connected to the backlight unit 36 ​​via the flexible wiring substrate 32. As the backlight unit 36, various types of backlight units can be used, and as the light source, there are light sources using light emitting diodes (LEDs) and cold cathode fluorescent lamps (CCFLs). In addition, a lighting device using a light guide plate arranged on the back side of the display panel and LEDs or cold cathode fluorescent lamps arranged on the side of the light guide plate can be used, and a lighting device using a point light source in which light emitting elements are arranged in a planar manner on the back side of the display panel can also be used. The lighting device is not limited to a backlight source, and a surface light lamp arranged on the display surface side of the display panel can also be used. Furthermore, in the case where the display device is a reflective display device or the display panel uses an organic EL, the structure may also not include a lighting device.

[0056] exist Figure 1 Although omitted, the display device includes a secondary battery, a power supply circuit, and the like.

[0057] [Pixel Array]

[0058] Figure 2 2 is a circuit diagram of the pixel array 18. The pixel array 18 is formed in the center of the first substrate 12 and includes a plurality of (for example, 1080×1920) pixels 40 arranged in a matrix. In addition, one pixel 40 includes sub-pixels 42 of three colors: red, green, and blue. R , 42 G , 42 B (Sometimes collectively referred to as 42). The color components of the sub-pixel can be three colors other than red, green, and blue, or four or more colors including red, green, blue, and other colors (such as white). Each sub-pixel 42 has a switching element 45 including a thin film MOSFET, a pixel electrode 47, and a common electrode 48. In the circuit diagram, each pixel 40 includes a common electrode 48, but in reality, a separate common electrode 48 is not provided. Instead, a common electrode 22 (see Figure 3 , Figure 4 ) and the portion facing the pixel electrode 47 virtually becomes the common electrode 48 of each sub-pixel 42. One or more pixels 40 (in Figure 2 The common electrode 48 of the sub-pixel 42 included in (representing the case of one pixel) is included in one common electrode 22.

[0059] The sources of the switching elements 45 of the sub-pixels 42 of each column are connected to a common source line (also called a signal line) 44. The source line 44 is Fig. 6A , Figure 6B As shown in FIG. 1 , the gates of the switching elements 45 of the sub-pixels 42 of each row are connected to a common gate line (also called a scanning line) 46. The gate line 46 is connected to Fig. 6A , Figure 6B The gate driver 102 is shown in FIG.

[0060] The common electrode 48 of each sub-pixel is included in the common electrode 22, so that the plurality of (in Figure 2 The common electrode lines 50 (three in the example) are equivalent to one common electrode 22. The gate lines 46 are formed by extending in the X direction, and the source lines 44 are formed by extending in the Y direction. That is, the sub-pixels 42 are formed near the intersections of the gate lines 46 and the source lines 44.

[0061] [Section structure]

[0062] Figure 3 express Figure 1 The cross-sectional structure of the display device along the X direction. A first optical element 52, a first substrate 12, a liquid crystal layer 54, a second substrate 14, and a second optical element 56 are provided on the backlight source 36. Figure 3 The configuration using the FFS (Fringe Field Switching) mode as the display mode is shown, but other display modes may also be used. The first substrate 12 and the second substrate 14 are bonded together in a state where a predetermined cell gap is formed. The liquid crystal layer 54 is maintained in the cell gap between the first substrate 12 and the second substrate 14.

[0063] The first substrate 12 includes a light-transmitting first insulating substrate 58 such as a glass substrate or a resin substrate. Although not shown in the figure, the source region, the drain region, and the gate region of the switching element 45 are formed in the surface region of the first insulating substrate 58 opposite to the second substrate 14. A first insulating layer 60 is formed on the surface of the first insulating substrate 58, and a plurality of source lines 44 are formed on the surface of the first insulating layer 60. Each source line 44 is formed to extend in the Y direction, and the arrangement direction of the plurality of source lines 44 is the X direction. A second insulating layer 62 is formed on the surface of the first insulating layer 60.

[0064] A plurality of common electrodes 22 are formed on the surface of the second insulating layer 62. Each common electrode 22 is formed to extend in the Y direction, and the arrangement direction of the plurality of common electrodes 22 is the X direction. One common electrode 22 is formed for three source lines 44 corresponding to a plurality of, for example, three sub-pixels constituting one pixel. The size of the common electrode 22 is not limited thereto, and one common electrode 22 may be formed for three times the number of source lines 44 corresponding to a plurality of pixels. Each common electrode 22 is in the shape of a long strip extending in the Y direction, and the arrangement direction of the plurality of common electrodes 22 is the X direction. A metal layer 64 is formed on the surface of the common electrode 22 for achieving low resistance, but the metal layer 64 may also be omitted. The metal layer 64 is also formed along the Y direction.

[0065] A third insulating layer 66 is formed on the surface of the second insulating layer 62. A plurality of pixel electrodes 47 are formed on the surface of the third insulating layer 66. The pixel electrodes 47 are respectively located between adjacent source lines 44. The portion of the common electrode 22 facing the pixel electrodes 47 corresponds to Figure 2 The pixel common electrode 48 is shown. Each pixel electrode 47 may have a slit 68. The pixel electrode 47 is formed of a transparent electrode material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) so as not to hinder display. The first alignment film 70 covers the pixel electrode 47 and the third insulating film 66.

[0066] The second substrate 14 includes a light-transmitting second insulating substrate 72 such as a glass substrate or a resin substrate. A black matrix 74 and a color filter 76 are formed on the surface of the second insulating substrate 72 opposite to the first substrate 12. R , 76 G , 76 B (Sometimes also collectively referred to as 76 ), a cover layer 78 and a second alignment film 80 are formed on the surface facing the first substrate 12 .

[0067] The black matrix 74 is arranged so as to divide each sub-pixel. R , 76 G , 76 B A portion of the black matrix 74 overlaps with the color filter 76. R It is a red filter, color filter 76 G It is a green filter, color filter 76 B is a blue filter. R , 76 G , 76 B The covering layer 78 is formed of a transparent resin material.

[0068] A plurality of detection electrodes 24 are formed on the outer surface of the second insulating substrate 72 ( Figure 3 Each detection electrode 24 is in a strip shape extending in the X direction, and the arrangement direction of the plurality of detection electrodes 24 is the Y direction.

[0069] As described above, the backlight unit 36 ​​is disposed on the back side of the display panel ( Figure 3 The first optical element 52 is disposed between the first insulating substrate 58 and the backlight unit 36. The second optical element 56 is disposed on the upper side of the detection electrode 24. The first optical element 52 and the second optical element 56 each include at least a polarizing plate. The first optical element 52 and the second optical element 56 may include a phase difference plate as required.

[0070] [Touch detection principle]

[0071] Figure 4 An example of the basic structure of a mutual inductance touch panel 20 is shown. The detection electrodes 24-1, 24-2, ... (sometimes collectively referred to as 24) formed on the second substrate 14 are in the shape of long strips extending in the X direction and are arranged in the Y direction. The common electrode 22 formed on the first substrate 12 is in the shape of long strips extending in the Y direction and is arranged in the X direction. That is, on the touch panel 20, the common electrode 22 is orthogonal to the detection electrode 24. The detection electrode 24 or the common electrode 22 can be arranged in an inclined direction other than the X direction or the Y direction, and the detection electrode 24 and the common electrode 22 can also cross at any angle other than 90 degrees. In addition, the shapes of the detection electrode 24 and the common electrode 22 can be any shape, for example, they can be small rectangles corresponding to a number of pixels. The source line extends in the Y direction and is parallel to the common electrode. This configuration is called a vertical COM type. The configuration of the orthogonal detection electrodes 24 and common electrodes 22 on the touch panel 20 is the same as Figure 4 On the contrary, the detection electrode 24 can be set to a long strip shape extending in the Y direction, and the common electrode 22 can be set to a long strip shape extending in the X direction. In this case, the source line intersects with the common electrode. This configuration is called a horizontal COM type. The following description takes the vertical COM type as an example, but the present invention can also be applied to the horizontal COM type in the same way.

[0072] A liquid crystal layer 54 is present between the first substrate 12 and the second substrate 14, and the detection electrode 24 and the common electrode 22 are arranged at a distance from each other. Therefore, there is an electrostatic capacitance C1 between the detection electrode 24 and the common electrode 22. It is not necessary to provide one detection electrode 24 for each row of the pixel array, and it is sufficient to provide one detection electrode 24 for any plurality of rows. It is also not necessary to provide one common electrode 22 for each pixel in each column of the pixel array, and it is sufficient to provide one common electrode 22 for any plurality of pixels in the pixel array.

[0073] The common electrodes 22-1, 22-2, ... are driven in sequence by pulse-shaped driving signals. When a human finger touches or approaches the intersection of the detection electrode 24-3 and the common electrode 22-4 and supplies a driving signal to the common electrode 22-4, a pulse-shaped detection signal having a lower level than the signal obtained from the other detection electrodes 24-1, 24-2, 24-4, 24-5, ... is output from the detection electrode 24-3. The detection electrode 24 monitors the fringe electric field from the common electrode 22. When a conductive object such as a finger approaches, the fringe electric field is shielded, the electrostatic capacitance changes, and the detection potential of the detection electrode 24 decreases. The mutual inductance touch sensor processes the difference in the detection potential as a detection signal of the touch position. The driving signal supplied to one common electrode may include multiple pulses or a single pulse. The pulse as a whole in the plurality of common electrodes is referred to as a driving signal Tx. That is, the driving signal Tx is a high-frequency pulse signal.

[0074] The value of the electrostatic capacitance C1 is different when the finger is close to the detection electrode 24 and when it is far away. Therefore, the level of the detection signal is also different when the finger is close to the detection electrode 24 and when it is far away. Therefore, the proximity of the finger to the screen of the display panel can be determined by the level of the detection signal. The touch position of the finger on the screen can be detected based on the driving timing of the common electrode 22 based on the driving pulse and the position of the detection electrode 24 that outputs the low-level detection signal.

[0075] The common electrode 22 is also used as a driving electrode for driving the liquid crystal for display. Figure 5 As shown, a plurality of display periods are set in one frame period, a touch detection period (also called a non-display period) is set between a display period and the next display period, and a display operation and a touch detection operation are performed in a time-sharing manner.

[0076] During the display period, a plurality of lines of image signals Vsig are written from the host device 26 to the display panel, and are supplied to all common electrodes 22 as a constant DC voltage driving signal for display, so that a plurality of lines of images corresponding to the image signals are displayed. The image signal Vsig includes a set of pixel signals as a time-division multiplexed signal of sub-pixel signals of red, green, and blue sub-pixels. The image signal Vsig is based on the RGB selection signal SEL. R / G / B The pixels are separated into sub-pixel signals of three colors. The number of rows displayed in one display period is determined so that one frame of display can be completed in one frame period.

[0077] During each touch detection period, driving signals Tx1, Tx2, Tx3, ... are sequentially supplied to the selected common electrodes 22-1, 22-2, 22-3, ..., and the voltage of the common electrode 22 changes. The common electrode driven during one touch detection period is not limited to one common electrode, and multiple common electrodes may be collectively driven during one touch detection period, and the number of common electrodes may be set arbitrarily.

[0078] In a mutual inductive touch sensor, all common electrodes are not driven simultaneously, but are driven one by one or more common electrodes in sequence. The former is called simultaneous drive, and the latter is called sequential drive. Sequential drive is not limited to sequentially driving multiple common electrodes, but also includes random drive. In the self-inductive touch sensor described later, either simultaneous drive or sequential drive can be performed. Therefore, Figure 5 The present invention is not limited to mutual-inductive touch sensors, but can also be applied to sequentially driven self-inductive touch sensors.

[0079] During touch detection, there are two driving methods for changing the voltage of the selected common electrode based on the driving signal. One method is a driving method (also called DC driving) in which a pair of switches connected in series are prepared for each common electrode, a high-level voltage line and a low-level voltage line are connected by the pair of switches, the middle point of the pair of switches is connected to the common electrode, the pair of switches provided at the selected common electrode are closed and opened by the driving signal pulse, and a high-level voltage or a low-level voltage corresponding to the level of the driving signal is supplied to the selected common electrode. The other method is a driving method (also called AC driving) in which the driving signal is directly supplied to the selected common electrode.

[0080] Next, refer to Fig. 6A , Figure 6B to Figure 10 The principle of self-inductive touch detection is described below. The self-inductive touch detection utilizes capacitance Cx1 of one of the common electrode 22 and the detection electrode 24 , for example, the common electrode 22 , and capacitance Cx2 generated by a conductive body such as a user's finger approaching the common electrode 22 .

[0081] Fig. 6A , Figure 6B This indicates a state where the user's finger is neither in contact with nor close to the touch panel. In this case, no electrostatic capacitance Cx2 is generated between the common electrode 22 and the finger. Fig. 6A This shows a state where the power source Vdd is connected to the common electrode 22 by controlling the switch SWc. Figure 6B This shows a state in which the power supply Vdd is not connected to the common electrode 22 by controlling the switch SWc, but the common electrode 22 is connected to the capacitor Ccp.

[0082] exist Fig. 6A In the state, capacitor Cx1 is charged. Figure 6B In the state of , the capacitor Cx1 is discharged. The charging of the capacitor Cx1 means that a constant signal is written to the common electrode 22, and the common electrode 22 is driven for touch detection. The discharging of the capacitor Cx1 means that a signal indicating a change in the electrostatic capacitance generated in the common electrode 22 is read. The above-mentioned writing and reading signals use a dedicated line for obtaining a detection signal.

[0083] on the other hand, Fig. 7A , Figure 7B This indicates a state where the user's finger is in contact with or close to the touch panel. In this case, an electrostatic capacitance Cx2 is generated between the common electrode 22 and the finger. Fig. 7A This shows a state where the power source Vdd is connected to the common electrode 22 by controlling the switch SWc. Figure 7B This shows a state where the power source Vdd is connected to the common electrode 22 by controlling the switch SWc, and the common electrode 22 is connected to the capacitor Ccp.

[0084] exist Fig. 7A In the state, capacitor Cx1 is charged. Figure 7B In this state, capacitor Cx1 is discharged. Figure 7B The voltage variation characteristics of the capacitor Ccp during discharge shown in FIG. 1 are obviously different from those of the capacitor Cx2. Figure 6B Therefore, in the self-inductance method, input position information (for example, the presence or absence of operation input) is determined by utilizing the fact that the voltage change characteristics of the capacitor Ccp are different depending on the presence or absence of the capacitor Cx2.

[0085] Fig. 8A An example of a basic circuit for self-inductive touch detection is shown. Figure 1 The touch detection circuit 34 is shown. Fig. 8A As shown, the common electrode 22 is connected to the first terminal of the voltage-dividing capacitor Cp and to the first input terminal of the comparator COMP. The common electrode 22 has its own capacitance Cx. The second input terminal of the comparator COMP is connected to the supply terminal of the comparison voltage Vref.

[0086] The second terminal of the capacitor Cp is connected to the power supply line of the voltage Vcc via the switch SW1. The second terminal of the capacitor Cp is connected to the first terminal of the capacitor Cc via the resistor Rc. The second terminal of the capacitor Cc is connected to a reference potential (eg, ground potential).

[0087] The switch SW2 is connected between the second terminal of the capacitor Cp and the reference potential, and the switch SW3 is connected between the first terminal of the capacitor Cp and the reference potential.

[0088] illustrate Fig. 8AThe circuit operation. Switch SW1 can be closed at a constant cycle to charge capacitor Cc. When capacitor Cc is charged, switches SW2 and SW3 are closed. When capacitor Cc is charged, switches SW1, SW2, and SW3 are all opened, and the charge of capacitor Cc is maintained.

[0089] Next, the switches SW2 and SW3 are closed for a constant time. In addition, the switch SW1 is kept open. In this way, most of the charges of the capacitors Cp and Cx are released, and part of the charges of the capacitor Cc are released via the resistor Rc.

[0090] Next, switches SW1, SW2, and SW3 are all turned off. In this way, the charge of capacitor Cc moves to capacitors Cp and Cx. The equivalent circuit at this time can be seen as Figure 8B Then, the voltage Vx of the capacitor Cx is compared with the comparison voltage Vref or the threshold voltage Vth in the comparator COMP.

[0091] like Figure 8B As shown in the equivalent circuit of , when switches SW1, SW2, and SW3 are all turned off, the charge of capacitor Cc moves to capacitors Cp and Cx, and then the change of voltage Vx of capacitor Cx is compared with comparison voltage Vref in comparator COMP. The above-mentioned operation is repeated until Vx < Vref.

[0092] That is, after charging the capacitor Cc, the switches SW2 and SW3 are closed for a constant time. In addition, the switch SW1 remains open. In this way, most of the charges of the capacitors Cp and Cx are released, and part of the charge of the capacitor Cc is released via the resistor Rc. In addition, the switches SW1, SW2, and SW3 are all opened. In this way, the charge of the capacitor Cc is transferred to the capacitors Cp and Cx.

[0093] The relationship between the voltages Vp, Vc, Vx and the capacitances Cp, Cc, Cx is expressed by the following equations (1) to (3).

[0094] Vc=Vp+Vx (1)

[0095] Vp:Vx=(1 / Cp):(1 / Cx) (2)

[0096] Vx=(Cp / (Cp+Cx))×Vc (3)

[0097] As described above, after the capacitor Cc is charged to the voltage Vc via the switch SW1, if the switches SW2 and SW3 are repeatedly closed and opened while the switch SW1 is opened, the voltage Vc of the capacitor Cc gradually decreases, and the voltage Vx of the capacitor Cx also gradually decreases. This action, that is, the action of repeatedly closing and opening the switches SW2 and SW3 after the capacitor Cc is charged to the voltage Vc, continues until the voltage Vx becomes lower than the comparison voltage Vref.

[0098] Fig. 9 An example of a waveform showing a change in the voltage Vc of the capacitor Cc and an output waveform of the comparator COMP is shown. The horizontal axis represents time, and the vertical axis represents voltage.

[0099] When the switch SW1 is closed, the capacitor Cc is charged to the voltage Vcc. Then, the switches SW1, SW2, and SW3 are all turned off, and the charge of the capacitor Cc is transferred to the capacitors Cp and Cx. Then, the change of the voltage Vx of the capacitor Cx is compared with the comparison voltage Vref in the comparator COMP.

[0100] The characteristics of the change or degree of change of the voltage Vc varies according to the total value of the capacitance Cp and the capacitance Cx. The change of the capacitance Cc also affects the voltage Vx of the capacitance Cx. The value of the capacitance Cx varies according to the proximity of the user's finger to the common electrode 22.

[0101] Therefore, if Fig. 9 As shown, when the finger is far from the common electrode 22, the characteristic VCP1 is accompanied by a slow change, and when the finger is close to the common electrode 22, the characteristic VCP2 is accompanied by a fast change. When the finger is close to the common electrode 22, the decrease rate of Vc is greater than that when the finger is far away, because the value of the capacitance Cc is increased by the capacitance of the finger.

[0102] The comparator COMP compares the voltage Vp with the comparison voltage Vref or the threshold voltage Vth in synchronization with the repeated closing / opening of the switches SW2 and SW3. When Vp>Vref, the comparator COMP obtains an output pulse. However, when Vp<Vref, the comparator COMP stops outputting pulses.

[0103] The output pulse of the comparator COMP is monitored by a measurement circuit or measurement application (not shown) in the touch detection circuit 34. That is, after the capacitor Cc is charged once, short-term discharge is repeatedly performed by the switches SW1 and SW2, and the value of the voltage Vp is repeatedly measured.

[0104] At this time, the period (MP1 or P2) during which the output pulse of the comparator COMP is obtained may be measured, or the number of output pulses of the comparator COMP (the number of pulses from the time when Cc is charged until Vp<Vref) may be measured.

[0105] When the finger is far from the common electrode 22, the period is long, and when the finger is close to the common electrode 22, the period is short. When the finger is far from the common electrode 22, the comparator COMP has a large number of output pulses, and when the finger is close to the common electrode 22, the comparator COMP has a small number of output pulses.

[0106] Therefore, the proximity of the finger to the plane of the touch sensor can be determined by detecting the level of the pulse. In addition, if the common electrodes 22 are arranged two-dimensionally (in a matrix), the two-dimensional position of the finger on the plane of the touch sensor can be detected.

[0107] As described above, it is detected whether the user's finger will have an impact on the common electrode 22, but the detection time is in the order of tens of μs to several ms.

[0108] Fig.10 A driving method of a common electrode for self-sensing touch detection for simultaneous driving is shown. Figure 5 Similarly, a plurality of display periods are set in one frame period, and a touch detection period (also called a non-display period) is set between a display period and the next display period. In each touch detection period, drive signals Tx1, Tx2, Tx3, ... are supplied to all common electrodes 22-1, 22-2, 22-3, ...

[0109] The first embodiment can be similarly applied to a mutual-inductive touch sensor.

[0110] [Circuit configuration]

[0111] Fig.11 1 is a circuit diagram showing an example of the electrical configuration of a display device. A gate driver 102 is formed outside at least one long side (e.g., the left long side) of the pixel array 18 on the first substrate 12. An RGB selection switch (also called a multiplexer) 104 is formed outside one short side (e.g., the lower short side) of the pixel array 18 on the first substrate 12.

[0112] The display control device 16 includes: a host I / F 112, which is connected to the host device 26; and a touch panel I / F 122, which is connected to the touch detection device 34. The image signal output from the host device 26 is received by the host I / F 112, and is supplied to the pixel array 18 via the video memory 114, the line latch circuit 116, the source amplifier 118, and the RGB selection switch 104. The host I / F 112 performs interpolation processing and synthesis processing, etc., so that the image signal supplied from the host device 26 is suitable for display by the display device. The video memory 114 includes, for example, an SRAM or a DRAM that can store an image signal of one frame.

[0113] The line latch circuit 116 latches the image signal for one line output from the video memory 114. The output of the line latch circuit 116 is converted into an analog signal corresponding to the gray scale by the source amplifier 118. The image signal is a time-division multiplexed signal of sub-pixel signals of three colors, red, green, and blue, and is selected based on the RGB selection signal SEL. R / G / B The RGB selection switch 104 is operated to separate the sub-pixel signals into sub-pixel signals of each color and supply them to the pixel array 18. Figure 2 As shown, the switching elements 45 of the sub-pixels 42 of each row of the pixel array 18 are closed by the gate driver 102 via the gate lines 46. The sub-pixel signal is supplied to the pixel electrode 47 through the closed switching element 45. During the display period, a constant DC voltage for display is supplied to all the common electrodes 22, so that each sub-pixel 42 displays an image according to the pixel signal.

[0114] The control signal of the gate driver 102 and the selection control signal of the RGB selection switch 104 are supplied from the panel control signal generation circuit 124. The panel control signal generation circuit 124 also supplies a control signal to (the detection electrode of) the touch panel 20. The detection signal of the touch panel 20 is supplied to the touch detection device 34. The common electrode of the pixel array 18 is driven by the common electrode driver 126, and the control signal of the common electrode driver 126 is supplied from the panel control signal generation circuit 124. The driving method of the common electrode is set to DC drive.

[0115] Although not shown, the common electrode driver 126 includes a pair of switches connected in series to connect a high-level voltage line and a low-level voltage line. The common electrode driving method may be AC ​​driving. The display control device 16 includes, for example, a timing controller 128 that determines the operation timing of each part based on a synchronization signal or command received from the host device 26.

[0116] Fig.121 shows a portion related to driving the pixel matrix in the display control device 16. The pixel signal output from the source amplifier 118 is separated into three sub-pixel signals of RGB by the RGB selection switches 104-1, 104-2, ... (sometimes collectively referred to as 104). The sub-pixel signals of each color are supplied to the sub-pixels 42 of each column via the source lines 44-1, 44-2, 44-3 (sometimes collectively referred to as 44). R , 42 G , 42 B The source of the switching element 45. The sub-pixel 42 R , 42 G , 42 B The composition and Figure 2 The structure shown is the same. Only in the row where the switch element 45 is closed by the gate driver 102, the sub-pixel signal is supplied to the pixel electrode 47 of the sub-pixel 42. A predetermined number of source lines 44-1, 44-2, and 44-3 corresponding to one pixel 40, which are three in this case, are connected to the common electrode 22 via the SIG-COM switch 148. The common electrode 22 is driven by the common electrode driver 126. The closing and opening of the RGB selection switch 104, the SIG-COM switches 148-1, 148-2, ... (sometimes collectively referred to as 148) are controlled by the panel control signal generation circuit 124.

[0117] The panel control signal generating circuit 124 includes two voltage terminals 162, 164 and a protection terminal 166. The voltage terminal 162 is a positive voltage terminal, and the voltage terminal 164 is a negative voltage terminal. The protection terminal 166 is connected to the positive voltage terminal 162 and the negative voltage terminal 164 via the coupling capacitors 144, 142 in the flexible substrate (FPC) 28. The positive voltage terminal 162 and the negative voltage terminal 164 are also connected to the gate driver 102. The gate driver 102 controls the potential of the gate line 46 according to the voltage of the positive voltage terminal 162 and the voltage of the negative voltage terminal 164. In the case where two gate drivers 102 are respectively provided on the left and right sides of the pixel array 18, the gate lines of the odd-numbered pixel rows are connected to one gate driver, and the gate lines of the even-numbered pixel rows are connected to the other gate driver. The gate driver 102 includes a pair of switches 156, 154 connected in series between the positive voltage terminal 162 and the negative voltage terminal 164. The switches 156 and 154 are provided on each gate line, and the closing and opening of the switches 156 and 154 are controlled by the panel control signal generating circuit 124 .

[0118] The gate driver 102 sequentially supplies an on voltage to the plurality of gate lines 46 during the display period and sequentially selects the gate lines. The on voltage is supplied to the gate of the switching element 45 of the sub-pixel 42 connected to the selected gate line 46. The source and drain of the switching element 45 of the sub-pixel 42 to which the on voltage is supplied are conducted.

[0119] The source amplifier 118 supplies sub-pixel signals to the plurality of source lines 44 via the RGB selection switch 104 during the display period. The sub-pixel signals supplied to the source lines 44 are supplied to the corresponding pixel electrodes 47 via the switching elements 45 in which the source and drain are conducting. The common electrode driver 126 supplies a constant DC voltage to the common electrode 22 during the display period.

[0120] The common electrode driver 126 supplies the driving signal Tx to one or more common electrodes 22 during the touch detection period. The gate driver 102 drives (also referred to as protection drive) all gate lines 46 during the touch detection period by means of a protection signal, the protection signal including a pulse signal having the same phase and the same amplitude (not the absolute value of the amplitude level of the pulse but the difference between the high level and the low level) as the pulse signal constituting the driving signal Tx.

[0121] [Gate line protection drive]

[0122] Fig.13 The panel control signal generating circuit 124 related to the protection drive of the gate line is shown. The positive and negative external input power supplies VSP (e.g., +5.5V) and VSN (e.g., -5.5V) are connected to the boost circuits 170 and 180, respectively. The boost circuit 170 is a 2x boost circuit, and outputs a positive high voltage VGH of, for example, +11.0V. The high voltage VGH is stepped down by the LDO regulator 172, and becomes, for example, a positive output voltage VGHO of +8.5V.

[0123] The positive output voltage VGHO is supplied to the first terminal of the selector 174 connected to the positive voltage terminal 162. The second terminal of the selector 174 is in a high impedance state. The selector 174 selects the first terminal during the display period and outputs the positive output voltage VGHO from the positive voltage terminal 162, and selects the second terminal during the touch detection period and sets the positive voltage terminal 162 to a high impedance state. Although not shown, the high voltage VGH is also supplied to the pixel array 18 and the touch panel 20, and is used for various power supplies.

[0124] The boost circuit 180 is also a 2x boost circuit, and outputs a negative high voltage VGL of -11.0V, for example. The high voltage VGL is stepped down by the LDO regulator 182, and becomes a negative output voltage VGLO of -8.5V, for example. The negative output voltage VGLO is supplied to a first terminal of a selector 184 connected to the negative voltage terminal 164. The second terminal of the selector 184 is in a high impedance state. The selector 184 selects the first terminal during the display period and outputs the negative output voltage VGLO from the negative voltage terminal 164, and selects the second terminal during the touch detection period and sets the negative voltage terminal 164 to a high impedance state.

[0125] During one touch detection period, one or more common electrodes are selected, and a driving signal Tx is supplied to the selected common electrode. In the common electrode driver 126, a pulse signal of a certain frequency is amplified to a predetermined voltage level to generate a driving signal Tx. The difference (also called amplitude) between the high level (e.g., VSP=5.5V) and the low level (e.g., ground level) of the driving signal is set to VHI. In the panel control signal generating circuit 124, the terminal 175 for supplying the pulse signal that is the basis of the driving signal is connected to the protection amplifier 176, and the pulse signal generated at the terminal 175 is amplified by the protection amplifier 176 to generate a protection signal. Therefore, the protection signal and the driving signal Tx are in the same phase. In addition, the amplifier in the common electrode driver 126 and the protection amplifier 176 in the panel control signal generating circuit 124 can be set to amplify the pulse signal in a manner that is approximately equal to the difference between the high level and the low level of the driving signal Tx and the difference between the high level and the low level of the protection signal.

[0126] The protection signal output from the protection amplifier 176 is supplied to the first terminal of the selector 178 connected to the protection terminal 166. The second terminal of the selector 178 is grounded. The selector 178 is controlled by the protection enable signal, selects the first terminal during the enable period and outputs the protection signal from the protection terminal 166, and selects the second terminal during the disable period and grounds the protection terminal 166. The switching of the selectors 174, 178, and 184 is performed by the panel control signal generating circuit 124. The selector is connected between the first terminal and the second terminal, and can be composed of a CMOS switch that selects any one of the first terminal and the second terminal according to the control signal.

[0127] The protection terminal 166 is connected to the positive voltage terminal 162 via the coupling capacitor 144 in the flexible wiring substrate 28, and is connected to the negative voltage terminal 164 via the coupling capacitor 142 in the flexible wiring substrate 28. The positive voltage terminal 162 is connected to the gate line 46 via the switch 156, and the negative voltage terminal 164 is connected to the gate line 46 via the switch 154.

[0128] Reference Fig.14 Timing diagram of Fig.13 The panel control signal generating circuit 124 performs protection driving of the gate lines. Fig.14 (a) shows the state of the selector 178. Fig.14 (c) shows the states of the selectors 174 and 184. The selector 178 is switched to the disabled side during the display period and is switched to the enabled side during the touch detection period. Only during the enabled period, the pulse signal that becomes the basis of the drive signal Tx is supplied to the terminal 175. Therefore, when the selector 178 is switched from disabled to enabled, as shown in FIG. Fig.14As shown in (b), a protection signal corresponding to the pulse generated at the terminal 175 is output from the protection terminal 166. When the selector 178 is switched from enable to disable, the output of the protection signal from the protection terminal 166 stops.

[0129] like Fig.14 As shown in (d), the positive voltage terminal 162 outputs the positive output voltage VGHO as the output of the LDO regulator 172 during the display period. The positive output voltage VGHO is charged to the coupling capacitor 144. The capacitance of the coupling capacitor 144 is set to a level that can maintain the charged charge during the touch detection period while ignoring the leakage of the current. Fig.14 As shown in (d), the positive voltage terminal 162 outputs a pulse signal obtained by superimposing the protection signal output from the protection terminal 166 on the positive output voltage VGHO charged in the coupling capacitor 144 during the touch detection period.

[0130] like Fig.14 As shown in (e), the negative voltage terminal 164 outputs the negative output voltage VGLO as the output of the LDO regulator 182 during the display period. The negative output voltage VGLO is charged to the coupling capacitor 142. The capacitance of the coupling capacitor 142 is set to a level that can maintain the charged charge during the touch detection period while ignoring the leakage of the current. Therefore, as shown in FIG. Fig.14 As shown in (e), the negative voltage terminal 164 outputs a pulse signal obtained by superimposing the protection signal output from the protection terminal 166 on the negative output voltage VGLO charged in the coupling capacitor 142 during the touch detection period.

[0131] The gate line 46 is connected to the positive voltage terminal 162 of the panel control signal generating circuit 124 via the switch 156 in the gate driver 102, and is connected to the negative voltage terminal 164 of the panel control signal generating circuit 124 via the switch 154 in the gate driver 102. Fig.14 As shown in (f), the switch 156 is normally open and is closed only when the gate line 46 is turned on during the display period. Fig.14 As shown in (g), the switch 154 is usually closed and is opened only when the gate line 46 is turned on during the display period. Fig.14 As shown in (h), during the display period, the negative output voltage VGLO is usually supplied to the gate line 46, and the positive output voltage VGHO is supplied only when the switch 154 is opened and the switch 156 is closed, and the switch element 45 is closed.

[0132] During touch detection, a signal in which a protection signal output from the protection terminal 166 is superimposed on the negative output voltage VGLO generated at the negative voltage terminal 164 is supplied to the gate line 46. The signal generated at the terminal 164 is a negative voltage, so even if the signal superimposed with the protection signal is supplied to the gate line 46, the switching element 45 of the sub-pixel will not be closed.

[0133] The protection signal is a pulse signal having the same phase and amplitude as the drive signal Tx supplied to the common electrode during the touch detection period, so during the touch detection period, the gate line 46 is pulse driven with the same amplitude and phase as the drive signal Tx. Therefore, it is difficult to generate parasitic capacitance between the common electrode and the gate line, thereby reducing the load on the common electrode.

[0134] like Fig.14 As shown in (i), the RGB selection switch 104 selects the sub-pixels of R, G, and B in sequence during the display period and is disconnected during the touch detection period. Therefore, the source line 44 is in a high impedance state during the touch detection period. Fig.14 As shown in (j), the SIG-COM switch 148 is opened during the display period and closed during the touch detection period. During the touch detection period, all SIG-COM switches 148 may be closed. In the case of sequential driving, only the SIG-COM switch 148 connected to the common electrode 22 supplied with the drive signal Tx may be closed. Therefore, during the touch detection period, the common electrode 22 and the source line 44 are connected to each other, and the drive signal Tx ( Fig.14 (k)) is also supplied to the source line 44 via the SIG-COM switch 148. This can reduce the influence of the parasitic capacitance between the common electrode 22 and the source line 44, and can drive the common electrode 22 with a desired waveform by the drive signal Tx.

[0135] The common electrode 22 is formed of a transparent electrode material such as ITO or IZO, and the source line 44 is generally formed of metal, so the resistance of the common electrode 22 is higher than the resistance of the source line 44. When the common electrode 22 and the source line 44 are connected to each other during touch detection, there is an advantage that the resistance of the common electrode 22 is reduced and power consumption is reduced.

[0136] like Fig.14 As shown in (k), the common electrode driver 126 that drives the common electrode 22 outputs a constant DC voltage during the display period, and outputs a driving signal Tx as a high-frequency pulse during the touch detection period.

[0137] As described above, during the touch detection period in which the driving signal Tx is supplied to the common electrodes 22-1, 22-2, ..., a protection signal as a pulse signal having the same amplitude and phase as the driving signal is supplied to the gate line 46 intersecting the common electrode 22, so that it is difficult to generate parasitic capacitance between the common electrode 22 and the gate line 46 in the pixel array 18. Therefore, during the touch detection period, the responsiveness of the driving of the common electrode 22 based on the driving signal is good, so the detection accuracy is not reduced, and the detection time is not prolonged. Moreover, during the touch detection period, the source line 44 and the common electrode 22 are connected to each other, so it is difficult to generate parasitic capacitance between the source line 44 and the common electrode 22 in the pixel array 18, or it is also difficult to generate parasitic capacitance between the source line 44 and the common electrode 22 in the pixel array 18. Therefore, during the touch detection period, the influence of the parasitic capacitance in the pixel array 18 caused by the driving pulse of the common electrode can be suppressed.

[0138] [Select switch]

[0139] Fig.15 1 shows a portion related to the generation of the selection control signal of the RGB selection switch 104 in the panel control signal generation circuit 124. The CMOS switch 190 as a selector R , 190 G , 190 B The CMOS switch 190 is connected between the external input power supply VSP and VSN. The CMOS switch 190 includes a PMOSFET and an NMOSFET connected in series. In the CMOS switch 190, the PMOSFET is connected to the VSP side, the NMOSFET is connected to the VSN side, and the gates of the two FETs of the PMOSFET and the NMOSFET are connected to the clock terminal CLK. The CMOS switch 190 outputs either VSP or VSN from the connection point of the two FETs according to the level of the clock terminal CLK. The output of the CMOS switch 190 is passed through the inverter 191 as the selection control signal sel R 、sel G 、sel B The voltage is supplied to the selection switch 104. The power supply of the inverter 191 is connected to VSP and VSN so that the power supply can output a voltage for driving the next stage.

[0140] The selection switch 104 includes switches 104 that selectively pass or block red, green, and blue sub-pixel signals. R , 104 G , 104 B Each switch 104 R , 104 G , 104 B The CMOS transfer gate is composed of PMOSFET 192 and NMOSFET 196. The selection control signal selR 、sel G 、sel B Supplied to the gate of NMOSFET196, it is used as the inversion selection control signal sel via the inverter 194. XR 、sel XG 、sel XB It is supplied to the gate of PMOSFET 192. The power supply of inverter 194 is also connected to VSP and VSN so that it can output a voltage to drive the next stage.

[0141] Fig.16 is through Fig.15 The panel control signal generating circuit 124 generates a selection control signal sel R 、sel G 、sel B The waveform diagram of Fig.16 As shown in (a), (d), and (g), the clock CLK R ,CLK G ,CLK B This is a pulse signal with a phase difference of one pulse period but the same period. It is generated during the display period but not during the touch detection period. CMOS switch 190 R , 190 G , 190 B At the clock CLK R ,CLK G ,CLK B During the high level period, the negative voltage VSN is output. R ,CLK G ,CLK B The positive voltage VSP is output during the low level period. This output is inverted by the inverter 191, so the selection control signal sel R 、sel G 、sel B like Fig.16 (b), (e), and (h) are signals synchronized with the clock CLK. XR 、sel XG 、sel XB exist Fig.16 (c), (f), and (i) show that the selection switch 104 selects the control signal sel R 、sel G 、sel B Closed during high level.

[0142] Other embodiments are described below. Other embodiments are contents related to partial modifications of the first embodiment, and embodiments obtained by appropriately combining any number of other embodiments can be realized.

[0143] [Second embodiment]

[0144] In a first embodiment, if Fig.14 As shown in (h), the objects to be protected and driven based on the protection signal synchronized with the driving signal Tx for touch detection during the touch detection period are: the gate line 46 in the pixel array 18; and the source line 44 to which the driving signal is supplied by closing the SIG-COM switch 148. In the first embodiment, as Fig.14 As shown in (i), the RGB selection switch 104 for separating the pixel signal into sub-pixel signals is closed in sequence during the display period and opened during the touch detection period. Therefore, parasitic capacitance may be generated in the control signal line of the RGB selection switch 104 during the touch detection period. A second embodiment for suppressing the influence of the parasitic capacitance is described. Similar to the first embodiment, the second embodiment can also be applied to both self-inductive touch sensors and mutual-inductive touch sensors.

[0145] Fig.17 The selection control (SEL) signal generation circuit 202 of the RGB selection switch 104 in the panel control signal generation circuit 124 of the second embodiment R Other color selection control signal generating circuit 202 G , 202 B The period switching signal (high level during the touch detection period) and the protection enable signal are input to the AND gate 204 .

[0146] PMOSFETs 205 and 206 are connected in series between the positive voltage terminal 162 and the external input power supply VSP. PMOSFET 205 is connected to the positive voltage terminal 162, and PMOSFET 206 is connected to the external input power supply VSP. The output of AND gate 204 is connected to the gate of PMOSFET 206, and the output of AND gate 204 is connected to the gate of PMOSFET 205 via inverter 207. The power supply of inverter 207 is connected to the positive voltage terminal 162 ground so that it can output a voltage to drive the next stage.

[0147] NMOSFET 208 and PMOSFET 209 are connected in series between negative voltage terminal 164 and external input power supply VSN. NMOSFET 208 is connected to negative voltage terminal 164, and PMOSFET 209 is connected to external input power supply VSN. The output of AND gate 204 is connected to the gates of NMOSFET 208 and PMOSFET 209.

[0148] PMOSFET 210 and NMOSFET 212 are connected in series between the connection point of PMOSFET 205 and 206 and the connection point of NMOSFET 208 and PMOSFET 209. PMOSFET 210 is connected to the connection point of PMOSFET 205 and 206, and NMOSFET 212 is connected to the connection point of NMOSFET 208 and PMOSFET 209.

[0149] Clock CLK R The gates of PMOSFET 210 and NMOSFET 212 are connected via level shifter 214 and inverter 215. The connection point of PMOSFET 210 and NMOSFET 212 is connected to the first terminal 216a of selector 216. The second terminal 216b of selector 216 is connected to the positive voltage terminal 162. Selector 216 is controlled by the protection enable signal, and selects the first terminal 216a during the disable period and the second terminal 216b during the enable period. The selection control signal SEL R The output from the selector 216 is supplied to the switch 104. R The power supply of the inverter 215 is connected to the connection point of the PMOSFETs 205 and 206 and the connection point of the NMOSFET 208 and the PMOSFET 209 so that the power supply of the inverter 215 can output a voltage for driving the next stage.

[0150] The connection point of PMOSFET 210 and NMOSFET 212 is connected to the first terminal 217a of selector 217 via inverter 224. The second terminal 217b of selector 217 is connected to negative voltage terminal 164. Selector 217 is also controlled by the protection enable signal, and selects the first terminal 217a during the disable period and the second terminal 217b during the enable period. The inverted selection control signal SEL XR The output from the selector 217 is supplied to the switch 104. R The power supply of the inverter 224 is connected to the ground line of the external input power supply VSP in order to output the voltage for driving the next stage. In addition, the level shifter is sometimes connected to the gates of the PMOSFET 205, 206, NMOSFET 208, and PMOSFET 209.

[0151] Fig.18 It means by Fig.17 The selection control signal generating circuit 202 R The generated selection control signal SEL R , SEL XR Waveform diagram of . Fig.18(a) and (b) represent the protection enable signal and the touch detection period signal, respectively. The protection enable signal is at a high level during the enable period, and the touch detection period signal is at a high level during the touch detection period. Fig.14 Similarly, the protection enable signal is disabled (low level) during the display period and enabled (high level) during the touch detection period. The touch detection period signal is low level during the display period and high level during the touch detection period. Therefore, if Fig.18 As shown in (c), the output of the AND gate 204 is at a low level during the display period and at a high level during the touch detection period. Fig.18 (d) The clock CLK shown R is with Fig.16 The same clock as that in (a) is generated during the display period but not during the touch detection period.

[0152] During the display period, the output of AND gate 204 is at a low level, so PMOSFET 206, 209 is closed. Selectors 216, 217 select first terminals 216a, 217a. PMOSFET 210, NMOSFET 212 are switched on according to clock CLK R The high and low levels are closed, so if Fig.18 (g) shows the selection control signal SEL R Becomes according to the clock CLK R The high and low levels of VSP and VSN become pulses of VSP and VSN levels, such as Fig.18 As shown in (h), the selection control signal SEL is inverted. XR Becomes according to the clock CLK R The high and low levels become pulses of VSN and VSP levels.

[0153] During touch detection, the output of AND gate 204 is high, so PMOSFET 205 and NMOSFET 208 are closed. Selectors 216 and 217 select second terminals 216b and 217b. Fig.18 (g) shows the selection control signal SEL R becomes the same signal as the signal output from terminal 162, such as Fig.18 As shown in (h), the selection control signal SEL is inverted. XR The same signal as the signal output from the terminal 164 is obtained. That is, the selection control signal SEL R It is a pulse signal with a protection signal superimposed on the positive output voltage VGHO, and the inversion selection control signal SEL XR It is a pulse signal in which a protection signal is superimposed on the negative output voltage VGLO.

[0154] Thus, in the second embodiment, the selection control signal of the RGB selection switch 104 is modulated according to the protection signal synchronized with the drive signal Tx during touch detection, and therefore, it is difficult to generate parasitic capacitance between the selection control signal line, the inversion selection control signal line and the source line in the wiring area outside the pixel array 18.

[0155] Moreover, in the second embodiment, the selection control signal changes level between VSP (e.g., +5.5V) and VSN (e.g., -5.5V) during the display period, and during the touch detection period, the low level of the selection control signal is VGHO, which is higher than VSP. On the other hand, similarly to the first embodiment, during the touch detection period, the SIG-COM switch 148 is closed, and therefore, the drive signal Tx from the common electrode driver 126 is returned from the common electrode 22 to the RGB selection switch 104 via the source line 44. During the touch detection period, when the selection control signal changes level between VSP and VSN as during the display period, if noise or the like is mixed into the selection control signal, the RGB selection switch 104 is closed, and the drive signal is input to the source amplifier 118 via the RGB selection switch 104, and the source amplifier 118 may be damaged. However, by generating a Fig.18 (g) Fig.18 The selection control signal and the inversion selection control signal shown in (h) can reliably keep the RGB selection switch 104 OFF during the touch detection period.

[0156] When the second embodiment is applied to a mutual-inductive touch sensor, the driving signal is as follows: Figure 5 As shown in the figure, the common electrode is supplied in sequence, so the protection drive can be performed only by the selection control signal of the RGB selection switch 104, which corresponds to the source line corresponding to the common electrode to which the drive signal is supplied. In order to achieve this, a SEL signal generation circuit can be set for each selection switch 104 connected to each source line.

[0157] [Third Embodiment]

[0158] A third embodiment relating to a modification of the selection control signal generating circuit of the second embodiment will be described. Fig.19 The selection control (SEL) signal generation circuit 222 of the third embodiment R Other color selection control signal generating circuit 222 G ,222 BThe selection control signal generation circuit of the first embodiment and the second embodiment may be provided in the display control circuit 16, or may be provided on the first substrate 12 like the gate driver 102 or the RGB selection switch 104, but the generation circuit 222 of the third embodiment is provided on the first substrate 12. Like the first and second embodiments, the third embodiment can also be applied to both self-inductive touch sensors and mutual-inductive touch sensors.

[0159] PMOSFETs 221 and 220 are connected in series to Fig.15 The supply selection control signal sel is shown R The PMOSFET 221 is connected to the selection control signal sel R terminal, PMOSFET 220 is connected to the positive voltage terminal 162 .

[0160] NMOSFET 223 and PMOSFET 222 are connected in series to Fig.15 The supply inversion selection control signal sel is shown XR The NMOSFET 223 is connected to the inversion selection control signal sel XR terminal, PMOSFET 222 is connected to the negative voltage terminal 164 .

[0161] The period switching signal and the protection enable signal are input to the AND gate 218. The output of the AND gate 218 is connected to the gate of the PMOSFET 221, and the output of the AND gate 218 is connected to the gates of the PMOSFETs 220 and 222 and the NMOSFET 223 via the inverter 232.

[0162] Select control signal SEL R The voltage is supplied from the connection point of PMOSFETs 221 and 220 to the switch 104. R The gate of NMOSFET 196 is inverted. The selection control signal SEL XR The voltage is supplied from the connection point of NMOSFET 223 and PMOSFET 222 to the switch 104. R The gate of PMOSFET192.

[0163] Fig. 20 It means by Fig.19 The selection control signal generating circuit 222 R The generated selection control signal SEL R , SEL XR Waveform diagram of . Fig. 20 (a) Fig. 20 (b) indicates Fig.18 (a) Fig.18 (b) The same protection enable signal and touch detection period signal. Fig. 20 As shown in (c), the output of the AND gate 218 becomes a high level when the touch detection period starts.

[0164] During the display period, the output of AND gate 218 is low level, so PMOSFET221 and NMOSFET223 are turned on. Fig. 20 As shown in (h), the selection control signal SEL R Becomes the same as the selection control signal sel R ( Fig. 20 (f)) The same signal, such as Fig. 20 (i) shows the inversion of the selection control signal SEL XR Becomes the inverted selection control signal sel R ( Fig. 20 (g))Same signal.

[0165] During touch detection, the output of AND gate 218 is high, so PMOSFETs 220 and 222 are turned on. Fig. 20 As shown in (h), the selection control signal SEL R becomes the signal of terminal 162 ( Fig. 20 (d)) The same signal, such as Fig. 20 (i) shows the inversion of the selection control signal SEL XR becomes the signal of terminal 164 ( Fig. 20 (e))Same signal.

[0166] That is, through Fig.19 The generating circuit 222 can also be used with Fig.18 Similarly, the selection control signal SEL is generated as a pulse signal in which the protection signal is superimposed on the positive output voltage VGHO. R and the inversion selection control signal SEL which is a pulse signal in which a protection signal is superimposed on the negative output voltage VGLO. XR , thereby being able to obtain the same effect as the second embodiment.

[0167] When the third embodiment is applied to a mutual inductive touch sensor, the common electrode Figure 5 As shown in the figure, the driving signal is supplied sequentially, so the protection drive can be performed only by the selection control signal of the RGB selection switch 104, which corresponds to the source line corresponding to the common electrode to which the driving signal is supplied. In order to achieve this, a SEL signal generation circuit can be set for each selection switch 104 connected to each source line.

[0168] [Fourth Embodiment]

[0169] In the second and third embodiments, the object of protection driving during the touch detection period is the selection control signal of the RGB selection switch 104. A fourth embodiment applied to a self-inductive touch sensor in which the input signal of the RGB selection switch 104, that is, the output signal of the source amplifier 118, is set as the object of protection driving during the touch detection period and all the driving electrodes are driven simultaneously will be described.

[0170] Liquid crystal deteriorates when a DC voltage is continuously supplied, so the voltage supplied to the source line is sometimes driven by AC. AC driving includes: a dot inversion method, which drives the vertically adjacent pixels in reverse polarity for each frame; and a column inversion method, which drives the horizontally adjacent pixels in reverse polarity for each frame without performing vertical inversion. The fourth embodiment is described by taking the column inversion method as an example.

[0171] like Fig.21D As shown, the source amplifier includes: a positive amplifier 248 operated by a positive power supply and a negative amplifier 249 operated by a negative power supply, and the image signal is amplified for each source line by any one of the amplifiers 248 and 249. For example, in a certain frame, the image signal of the odd-numbered source line is supplied to the positive amplifier 248, and the image signal of the even-numbered source line is supplied to the negative amplifier 249. The object of protection drive during touch detection is set to the output of the positive amplifier 248, and the output of the negative amplifier 249 is set to high impedance during touch detection. Fig.21A , Fig.21B , Fig. 21C An example of protection driving of the output signal of the positive amplifier 248 is shown in FIG.

[0172] Fig.21A The positive amplifier 248 includes an operational amplifier 248A, a terminal 175 ( Fig.13 ) is connected to the input of the operational amplifier 248A, and the terminal 175 supplies a pulse signal that becomes the basis of the drive signal Tx during the touch detection period. The operational amplifier 248A operates by the external input power supplies VSP and VSN. During the display period, the operational amplifier 248A inputs a normal image signal. During the touch detection period, the operational amplifier 248A amplifies the pulse signal of the terminal 175 and outputs a protection signal including a pulse with an amplitude of VHI (refer to Fig.14 (b)).

[0173] exist Fig.21AIn the embodiment, the positive amplifier 248 constituting the source amplifier amplifies the pulse that will be the basis of the drive signal Tx and generates a protection signal, but the positive amplifier 248 itself is set as a normal amplifier, and the protection signal is provided to its output terminal only during the touch detection period, and the protection signal is output from the output terminal of the amplifier. Fig.21B , Fig. 21C This example is shown in FIG.

[0174] Fig.21B The positive amplifier 248 includes close / open switches 248C, 248D, and 248E connected to the output terminal of the operational amplifier 248A that supplies the image signal. The close / open switches 248D and 248E are connected in series between the external input power supply VSP and the ground line, and the close / open switch 248C is connected between the output terminal of the operational amplifier 248A and the connection point of the close / open switches 248D and 248E. During touch detection, by opening the switch 248C, the switches 248D and 248E are alternately closed and opened in synchronization with the drive signal Tx, so that the output level of the operational amplifier 248A changes between the external input power supply VPN and the ground level. Therefore, it is possible to output from the output terminal of the operational amplifier 248A Fig.14 (b) shows the protection signal.

[0175] Fig. 21C The positive amplifier 248 includes: a closing / opening switch 248F connected to the output of the operational amplifier 248A supplying the image signal; and an operational amplifier 248G whose input is connected to the terminal 175. During the touch detection period, by opening the switch 248F, the operational amplifier 248G outputting the same pulse signal as the protection signal becomes the output of the positive amplifier 248. This configuration can also output the output terminal of the operational amplifier 248A. Fig.14 (b) shows the protection signal.

[0176] For example Fig.21A , Fig.21B , Fig. 21C The output of the positive amplifier 248 constructed as shown is as follows Fig.21D As shown, the output of the negative amplifier 249 is supplied to the second terminals of the selectors 238 and 242 via the selector 236. The first terminal of the selector 236 is connected to the first terminal of the selector 238, and the second terminal of the selector 236 is connected to the first terminal of the selector 242. The output of the negative amplifier 249 is supplied to the second terminals of the selectors 238 and 242 via the selector 240. The first terminal of the selector 240 is connected to the second terminal of the selector 238, and the second terminal of the selector 240 is connected to the second terminal of the selector 242.

[0177] The output of the selector 238 is connected to the odd-numbered source line S1, and the output of the selector 242 is connected to the even-numbered source line S2. The source lines S1 and S2 are connected to the RGB selection switches 104-1 and 104-2, respectively. The outputs of the positive and negative amplifiers are similarly supplied to the other source lines.

[0178] The selectors 236, 238, 240, and 242 are switched for each frame. The selectors 236, 238, 240, and 242 are set to output the output of the positive amplifier 248 to the source line S1 in a certain frame, for example, in an odd frame, and to output the output of the negative amplifier 249 to the source line S2. For example, the selectors 236, 238, 240, and 242 are set to output the output of the positive amplifier 248 to the source line S2 and the output of the negative amplifier 249 to the source line S1 in an even frame.

[0179] Fig. 22 (a) Fig. 22 (b) shows the selection control signal SEL of the RGB selection switch 104 in a certain frame, for example, an odd frame. R / G / B and invert the selection control signal SEL XR / XG / XB , Fig. 22 (c) Fig. 22 (d) shows the levels of the source lines S1 and S2.

[0180] In this way, by outputting a protection signal from the source amplifier 118 (positive amplifier 248 ) during touch detection, parasitic capacitance between the output line of the source amplifier 118 (the signal line between the source amplifier 118 and the RGB selection switch 104 ) and the common electrode 22 is less likely to occur.

[0181] [Fifth Embodiment]

[0182] In the fifth embodiment, the protection signal is output from the source amplifier 118 during the touch detection period, similarly to the fourth embodiment. The fourth embodiment is applied to the self-inductance driven simultaneously, while the fifth embodiment is applied to the mutual inductance touch sensor. As described above, the mutual inductance touch sensor sequentially selects the common electrodes 22-1, 22-2, ... during the touch detection period, and sequentially supplies the driving pulses Tx1, Tx2, ... to the selected common electrodes.

[0183] In the fourth embodiment of the self-inductive touch sensor applied to simultaneous driving, during the touch detection period, the positive amplifier 248 of the source amplifier 118 outputs a protection signal to all pixels of one row, and in the fifth embodiment of the mutual inductive touch sensor, as shown in FIG. Fig.23As shown, common electrodes are selected in sequence, and protection signals are output only from the positive amplifiers of the source amplifiers 118 corresponding to the selected common electrodes, and protection signals are not output from the positive amplifiers of the source amplifiers 118 corresponding to the unselected common electrodes. The first positive amplifier that outputs the protection signal during touch detection is labeled as positive amplifier (+) 254, and the second positive amplifier that does not output the protection signal during touch detection is labeled as positive amplifier (+′) 256.

[0184] The output of the positive amplifier (+') 256 is in a high impedance state during touch detection. The first positive amplifier (+) 254 and the second positive amplifier (+') 256 both include Fig.21A , Fig.21B , Fig. 21C The positive amplifier 248 is shown. By controlling the positive amplifier 248 to output / not output the protection signal during the touch detection period, the positive amplifier 248 can be used as the first and second positive amplifiers. Fig.21A , Fig.21B , Fig. 21C , Fig.21D The negative amplifier 249 shown is the same, outputting a pixel signal of negative polarity during display and outputting a high impedance signal during touch detection.

[0185] The common electrode driver 126 outputs a constant voltage VCOMDC for display during the display period, and outputs a driving signal Tx1 , Tx2 , . . . of each common electrode 22 - 1 , 22 - 2 , . . . during the touch detection period.

[0186] A voltage selection switch 252 is connected between the RGB selection switch 104 and the common electrode 22. The voltage selection switch 252 is used to connect any one of the voltage VCOMDC and the drive signal Tx to the source line during the touch detection period. The voltage selection switch 252 is switched by the panel control signal generation circuit 124 as follows: the source line corresponding to the selected common electrode, such as the common electrode 22-1, is connected to the drive signal Tx1, and the source line corresponding to the non-selected common electrode, such as the common electrode 22-2, ... is connected to the voltage VCOMDC.

[0187] Thus, a protection signal from the source amplifier 118 (positive amplifier 254) is applied to the drive signal Tx supplied from the common electrode driver 126 to the common electrode 22 during touch detection, so that the conversion rate of the drive signal Tx in the display panel is improved compared to the case where the common electrode 22 is driven only by the drive signal Tx, thereby improving the accuracy of touch detection.

[0188] The fifth embodiment can also be applied to a self-inductive touch sensor if it is driven sequentially.

[0189] [Sixth Embodiment]

[0190] The fifth embodiment in which a protection signal from the source amplifier 118 is applied to the drive signal Tx supplied from the common electrode driver 126 to the common electrode 22 during touch detection can also be applied to a mutual inductance touch sensor composed of two conventional chips (display controller IC and touch controller IC).

[0191] In a conventional display device composed of two chips, such as Fig.24 As shown, instead of outputting driving signals Tx1, Tx2, ... for each common electrode 22-1, 22-2, ... from the common electrode driver 126B, one driving signal TSVCOM is output for all common electrodes. The driving signal TSVCOM is supplied only to the selected common electrode via the TSVCOM selection switch 264 including switches corresponding to each common electrode 22-1, 22-2, ... as the driving signal Tx. The common electrode driver 126B also outputs a constant voltage VCOMDC. The constant voltage VCOMDC is supplied to the non-selected common electrode via the VCOMDC selection switch 262 including switches corresponding to each common electrode 22-1, 22-2, ...

[0192] In such a touch sensor having a conventional two-chip configuration, the supply source of the driving signal is only the TSVCOM terminal. If the load of the driving signal Tx is large, the stable characteristics may be deteriorated.

[0193] However, if Fig.24 As shown, the output of the source amplifier 118 is supplied to the pixel 40 via the RGB selection switch 104, and the output of the source amplifier 118 is supplied to the selected common electrode 22 via the SIG-COM switch 148. The SIG-COM switch 148 interconnects the common electrode 22 and the source line 44 during touch detection.

[0194] The constant DC voltage VCOMDC output from the common electrode driver 126B is supplied to the non-selected common electrode 22 via the VCOM selection switch 262. The drive signal TSVCOM output from the common electrode driver 126B is supplied to the selected common electrode 22 via the Tx selection switch 264. The VCOM selection switch 262 and the Tx selection switch 264 are connected in series between the voltage VCOMDC line and the voltage TSVCOM line, and the connection point between the VCOM selection switch 262 and the Tx selection switch 264 is connected to the common electrode 22. During the display period, the switch 262 is closed and the switch 264 is open. Therefore, the DC voltage VCOMDC is supplied to the common electrode 22 during the display period. During the touch detection period, the states of the switches 262 and 264 corresponding to the non-selected common electrode, such as 22-2, are the same as during the display period. During the touch detection period, the switches 262 and 264 related to the selected common electrode, such as 22-1, are opened and closed. Therefore, the drive signal TSVCOM is supplied to the common electrode 22 during the touch detection period.

[0195] Source amplifier 118 and Fig.23 That is, the source amplifier 118 corresponding to the selected common electrode 22 - 1 includes a first positive amplifier (+) 254 and a negative amplifier (−) 258 , and the source amplifier 118 corresponding to the unselected common electrode 22 - 2 includes a second positive amplifier (+′) 256 and a negative amplifier (−) 258 .

[0196] Fig.24 The common electrode driver 126B and the source amplifier 118 are provided in the display control device (display controller IC) 16, and the RGB selection switch 104, the VCOM selection switch 262, the Tx selection switch 264, and the SIG-COM switch 148 are provided in the display panel.

[0197] Fig.25 is a timing diagram related to selecting the drive of the common electrode, Fig.25 (a) shows a driving signal Tx supplied to the selected driving electrode, Fig.25 (b) shows the operation of the source amplifier 118, Fig.25 (c) shows the selection control signal SEL of the selection switch 104. R / G / B During the display period, the driving signal Tx is at a low level, and the selection control signal SEL R / G / B RGB is selected in sequence, and the source amplifier 118 outputs the image signal. During the touch detection period, the driving signal Tx becomes a pulse signal with repeated high and low levels, and the control signal SEL is selected. R / G / B This is a pulse signal in which a protection signal synchronized with the drive signal is superimposed on the VGHO level.

[0198] As in the fifth embodiment, the first positive amplifier 254 of the source amplifier 118 corresponding to the selected common electrode also outputs a pulse signal corresponding to the protection signal during the touch drive period. When the positive amplifier 254 outputs a pulse signal, power (power supply) is required for the rise and fall of the pulse, but no power is required during the period when the level is constant after the rise and fall, and thus the positive amplifier 254 becomes a high impedance state. Therefore, Fig.25 As shown in (b), the first positive amplifier 254 of the source amplifier 118 corresponding to the selected common electrode 22 is driven with a positive voltage VSP for the rise of the pulse during the touch drive period, and then becomes high impedance, and is driven with a ground level for the fall of the pulse. The high impedance can be achieved by disconnecting the power supply of the positive amplifier 254 or by connecting a switch to the output of the positive amplifier 254 and disconnecting the switch.

[0199] According to the sixth embodiment, similarly to the fifth embodiment, a protection signal from the source amplifier 118 (positive amplifier 254) is applied to the drive signal Tx supplied to the selected common electrode during the touch detection period, so the conversion rate of the drive signal Tx in the display panel is improved, and the accuracy of touch detection is improved. In addition, according to the sixth embodiment, the positive amplifier 254 is not driven continuously during the touch detection period, but becomes a high impedance state when the level is constant after rising and falling, so even if the supply source of the drive signal is only the TSVCOM terminal, the stability characteristics will not be deteriorated, and power consumption can be reduced.

[0200] [Seventh Embodiment]

[0201] Fig.26 This is a block diagram of the seventh embodiment applied to a self-inductive touch panel.

[0202] The first to fifth embodiments can also be applied to the self-inductive type. However, in the first to fifth embodiments, the shape of the common electrode is as follows: Figure 4 The common electrodes are arranged in an elongated shape along the pixel column (Y direction), and a plurality of common electrodes are arranged along the row direction (X direction). The seventh embodiment relates to a modification of the shape of the common electrode of the self-inductive touch panel.

[0203] exist Fig.26In the touch panel shown, the common electrodes 22 are arranged in a two-dimensional array, and the output signals from the common electrodes 22 can be used as the coordinates themselves. The common electrodes can be set for each pixel or for each plurality of pixels. In the case of being set for each plurality of pixels, they can be set for each plurality of pixels configured in a two-dimensional array. The shape of the common electrode can be any shape as long as it can cover the corresponding pixels. Moreover, the plurality of common electrodes may not be arranged vertically or horizontally. During touch detection, the common electrode driver 126, the source amplifier 118, and the panel control signal generation circuit 124 are driven in the same manner as in the above-mentioned embodiment, thereby Fig.26 In the self-inductive touch panel shown above, it is also possible to suppress the influence of the parasitic capacitance generated between the common electrode and the wiring on the driving signal of the common electrode for touch detection.

[0204] [Eighth Embodiment]

[0205] An eighth embodiment related to a modification example common to all the above-mentioned embodiments will be described. Fig. 27 FIG. 2 shows a part of the panel control signal generating circuit 124 related to the protection driving of the gate lines according to the eighth embodiment. Fig.13 The panel control signal generating circuit 124 of the first embodiment shown in the figure adds a voltage terminal 308. The output VGH (e.g., +11.0V) of the boost circuit 170, which boosts the positive external input power supply VSP (e.g., +5.5V) by 2 times, is supplied to the LDO regulator 172 and to the first terminal of the selector 312. The second terminal of the selector 312 becomes high impedance. The selector 312 selects the first terminal during display and the second terminal during touch detection. The output terminal of the selector 312 is connected to the voltage terminal 308.

[0206] In the eighth embodiment, Fig.13 In the flexible wiring board 28 shown, a coupling capacitor 316 is added between the voltage terminal 308 and the protection terminal 166 .

[0207] Reference Fig.28 Timing diagram based on Fig. 27 The panel control signal generating circuit 124 is used for protection driving of the gate lines. Fig.28 (a) represents the state of selector 178 (with Fig.14 (a) the same). Fig.28 (b) shows the state of the protection terminal 166 (with Fig.14 (b) same). Fig.28 (c) represents the state of selectors 174, 184, and 312 (selectors 174, 184 and Fig.14 (c) the same). Fig.28 (e) indicates the state of the positive voltage terminal 162 (with Fig.14 (d) is the same). During display, the selector 312 selects the first terminal, so the voltage of the terminal 308 is as follows Fig.28 (d) shows VGH. During display, selector 174 selects the first terminal, so the voltage of terminal 162 is as follows: Fig.28 (e) shows VGHO. During the display period, the selector 178 is connected to the disable side, so the terminal 166 is grounded. Therefore, during the display period, the voltage VGH is charged to the coupling capacitor 316.

[0208] When switching from the display period to the touch detection period, the selector 178 is switched to the enable side, so that the protection terminal 166 is Fig.28 (b) shows a pulsed protection signal output. The amplitude of the protection signal is VHI. When the selector 312 switches from the display period to the touch detection period, it switches to the second terminal (high impedance), so that the protection signal output from the protection terminal 166 is applied to the voltage terminal 308 via the coupling capacitor 316. The capacitance of the coupling capacitor 316 can be set to a level that can maintain the charged charge during the touch detection period so that the leakage of current can be ignored. Therefore, Fig.28 As shown in (d), the voltage of the voltage terminal 308 becomes a signal with a protection signal superimposed on VGH. Although not shown, the terminal 308 is also connected to the pixel array 18, and the power supply VGH is used as various power supplies. Therefore, when the gate line 46, the source line 44, the control signal line of the RGB selection switch 104, etc. are driven by protection during touch detection, it is possible that the influence of parasitic capacitance will also be generated in the internal wiring of the pixel array 18 and the touch panel 20 connected to the terminal 308. However, during touch detection, the voltage of the terminal 308 becomes a voltage with a protection signal superimposed on VGH (driven by protection), so the voltage VGH is also regarded as driven by protection, and the influence of parasitic capacitance will not be generated in the internal wiring.

[0209] As in the first embodiment, the selector 162 switches to the second terminal (high impedance) when switching from the display period to the touch detection period, so the protection signal output from the protection terminal 166 is applied to the positive voltage terminal 162 via the coupling capacitor 144. Fig.28 As shown in (e), the voltage of the positive voltage terminal 162 is a signal obtained by superimposing the protection signal on VGHO.

[0210] In the absence of coupling capacitor 316 Fig.13 In the case of a configuration of , when a protection signal is superimposed on the positive voltage terminal 162, it is possible that the positive voltage terminal 162 must be set to a voltage higher than the high voltage VGH according to the protection signal amplitude or the VGH / VGHO setting voltage. The difference between the voltage VGH and the voltage VGHO needs to be greater than the protection signal amplitude VHI. Fig.13In the self-inductance type shown, the protection signal amplitude is small, so even without the coupling capacitor 316, the difference between the protection voltage VGH and the voltage VGHO is greater than the protection signal amplitude VHI.

[0211] In the eighth embodiment, the protection signal is superimposed on the voltage of the terminal 308 through the coupling capacitor 316, so the voltage VGH is also protected and driven together with the voltage VGHO. Therefore, the difference between the voltage VGH and the voltage VGHO must be greater than the protection signal amplitude VHI, and the gate line can be reliably protected and driven.

[0212] [Summary of Implementation Methods]

[0213] The embodiments of the present invention include the following aspects.

[0214] (1) The display device comprises:

[0215] The pixel array 18 is composed of a plurality of pixels 40 arranged in rows and columns;

[0216] A plurality of common electrodes 22 are provided on the pixel array 18 for performing electrostatic capacitive touch detection;

[0217] The common electrode driver 126 supplies a DC voltage for display to the common electrode 22 during the display period, and supplies a driving signal Tx for touch detection to the common electrode 22 during the touch detection period;

[0218] a plurality of source lines 44 connected to the pixels 40 in each column of the pixel array 18;

[0219] A source amplifier 118 supplies image signals to the plurality of source lines 44;

[0220] a plurality of gate lines 46 connected to each row of pixels 40 in the pixel array 18;

[0221] The gate driver 102 sequentially supplies scanning signals to the plurality of gate lines 46 during the display period, and supplies protection signals having the same phase as the driving signal to the plurality of gate lines 46 during the touch detection period; and

[0222] The switch 148 is connected between the source line 44 and the common electrode 22 , and conducts the source line 44 and the common electrode 22 during a touch detection period.

[0223] According to the display device, during the touch detection period, the source line 44 and the common electrode 22 are connected by the switch 148, and the driving signal Tx flowing through the common electrode 22 also flows in the source line 44, so that no parasitic capacitance is generated between the source line 44 and the common electrode 22. In addition, during the touch detection period, the driving signal Tx flowing through the common electrode 22 also flows in the gate line 46, so that no parasitic capacitance is generated between the gate line 46 and the common electrode 22. Therefore, it is possible to prevent the accuracy of touch detection due to parasitic capacitance from being reduced, and the common electrode can be driven with a desired waveform by the driving signal Tx.

[0224] (2) In the display device of (1), the common electrode 22 is a vertical COM type common electrode and is parallel to the plurality of signal lines 44 .

[0225] (3) In the display device of (1), the common electrode 22 is a horizontal COM type common electrode and intersects with the plurality of signal lines 44 .

[0226] (4) The display device of (1) includes a plurality of detection electrodes 24 intersecting with a plurality of common electrodes 22. The driving signal Tx is supplied to the common electrode 22, and touch detection is performed by mutual induction based on the detection potential of the detection electrode 24.

[0227] (5) In the display device of (1), a driving signal is supplied to the common electrode 22 , and touch detection is performed by self-inductance based on a change in the electrostatic capacitance of the common electrode 22 .

[0228] (6) In the display device of (1), a plurality of touch detection periods are set in one frame period, and a touch detection period is set between a display period and a next display period. A constant DC voltage is supplied to the common electrode during the display period, and a driving pulse is sequentially supplied to the plurality of common electrodes during the touch detection operation.

[0229] Although several embodiments of the present invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments or their variations are included in the scope or purpose of the invention and are included in the scope equivalent to the invention described in the claims.

Claims

1. A display device, comprising: A pixel array, consisting of a plurality of pixels arranged in two dimensions, wherein the pixels include sub-pixels of multiple colors; A plurality of common electrodes, arranged on the pixel array, for electrostatic capacitive touch detection; a common electrode driver for supplying a voltage for display to the plurality of common electrodes during a display period, and for supplying a driving signal for touch detection in the common electrodes to the plurality of common electrodes during a touch detection period; A plurality of source lines connected to pixels in each column of the pixel array; A source amplifier for supplying an image signal obtained by time-division multiplexing sub-pixel signals of a plurality of colors to the plurality of source lines; A plurality of gate lines connected to pixels in each row of the pixel array; a gate driver that sequentially supplies scanning signals to the plurality of gate lines during a display period, and supplies signals having the same phase as the driving signal to the plurality of gate lines during a touch detection period; a selection switch composed of a plurality of transistors connected between the plurality of source lines and the source amplifier, separating the image signal output from the source amplifier into sub-pixel signals of the plurality of colors, and supplying the sub-pixel signals of the plurality of colors to the plurality of source lines; as well as a controller connected to the selection switch, the controller supplying a first control signal for sequentially closing the plurality of transistors to the gates of the plurality of transistors during a display period, and supplying a second control signal including a signal having the same phase as the drive signal to the gates of the plurality of transistors during a touch detection period, The source amplifier supplies a signal having the same phase as the drive signal to the selection switch during a touch detection period. The source amplifier includes a positive amplifier and a negative amplifier, and the positive amplifier outputs a signal having the same phase as the driving signal during touch detection.

2. The display device according to claim 1, wherein: The display device supplies the driving signal to the plurality of common electrodes at the same time, and performs self-inductive touch detection based on electrostatic capacitance of the common electrodes.

3. The display device according to claim 1, wherein: The display device supplies the driving signal to the plurality of common electrodes at the same time, and performs self-inductive touch detection based on electrostatic capacitance of the common electrodes.

4. The display device according to claim 1, wherein: The display device includes a plurality of detection electrodes intersecting the plurality of common electrodes. The display device sequentially supplies the driving signal to the plurality of common electrodes, and performs mutual inductance touch detection based on the detection potential of the detection electrode. During a touch detection period, a TSVCOM signal is supplied to the common electrode.

5. The display device according to claim 1, wherein: The source amplifier is driven by a predetermined power supply during a rising period and a falling period of a signal supplied to the selection switch during a touch detection period, and an output of the source amplifier is high impedance during a period in which a level of the signal is constant between the rising period and the falling period.

6. The display device according to claim 1, wherein: The plurality of common electrodes are arranged in two dimensions, The display device sequentially supplies the driving signal to the plurality of common electrodes, and performs self-inductive touch detection based on electrostatic capacitance of the common electrodes.

7. The display device according to claim 1, wherein: The gate driver includes a boost circuit, which boosts an external power supply voltage to generate a first voltage. The gate driver sequentially supplies a scanning signal based on the first voltage to the multiple gate lines during display, and supplies a signal with the same phase as the drive signal superimposed on the first voltage to the multiple gate lines during touch detection.

8. The display device according to claim 7, wherein: The gate driver includes a feedback circuit that superimposes a signal having the same phase as the drive signal on an output terminal of the booster circuit.

9. The display device according to claim 8, wherein: The signal having the same phase as that of the driving signal includes a pulse having the same amplitude as that of a pulse included in the driving signal.

10. The display device according to claim 1, wherein: The common electrode driver and the controller are included in one IC chip.

11. A driving method, which is a driving method of a display device, The display device comprises: A pixel array, consisting of a plurality of pixels arranged in two dimensions, wherein the pixels include sub-pixels of multiple colors; A plurality of common electrodes, arranged on the pixel array, for electrostatic capacitive touch detection; A common electrode driver connected to the plurality of common electrodes; A plurality of source lines connected to pixels in each column of the pixel array; a source amplifier connected to the plurality of source lines; A plurality of gate lines connected to pixels in each row of the pixel array; A gate driver connected to the plurality of gate lines; a selection switch, composed of a plurality of transistors, wherein the plurality of transistors are connected between the plurality of source lines and the source amplifier; as well as A controller connected to the selection switch, In the driving method, The common electrode driver supplies a voltage for display to the plurality of common electrodes during a display period, and supplies a driving signal for touch detection to the plurality of common electrodes during a touch detection period. The source amplifier supplies image signals to the plurality of source lines. The gate driver sequentially supplies scanning signals to the plurality of gate lines during a display period, and supplies signals having the same phase as the driving signal to the plurality of gate lines during a touch detection period. The selection switch separates the image signal output from the source amplifier into sub-pixel signals of a plurality of colors and supplies the sub-pixel signals of the plurality of colors to the plurality of source lines. The controller supplies a first control signal for sequentially closing the plurality of transistors to the gates of the plurality of transistors during a display period, and supplies a second control signal including a signal having the same phase as the drive signal to the gates of the plurality of transistors during a touch detection period, The source amplifier supplies a signal having the same phase as the drive signal to the selection switch during a touch detection period. The source amplifier includes a positive amplifier and a negative amplifier, and the positive amplifier outputs a signal having the same phase as the driving signal during touch detection.

12. The driving method according to claim 11, wherein: The display device further includes: A first switch is connected between the plurality of source lines and the plurality of common electrodes. The first switch conducts the plurality of source lines to the plurality of common electrodes during a touch detection period.

13. The driving method according to claim 11, wherein: The common electrode driver and the controller are included in one IC chip.

Images