JP2018045283A - Touch detection function-attached display device and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an image display duration to be elongated.SOLUTION: A touch detection function-attached display device comprises: a touch detection unit that includes electrodes of a first group and second group; a display unit; a control unit that has a first action mode conducting a display and touch detection at a first frame frequency, and a second action mode conducting a display and touch detection at a second frame frequency. The control unit is configured to sequentially supply a touch detection driving signal to the electrode of the first group in a touch detection period of the first action mode; conduct touch detection on the basis of a mutual electrostatic capacitance between the electrode of the first group and the electrode of the second group; concurrently supply the touch detection driving signal to the electrode of the first group in a touch detection period of the second action mode; conduct touch detection on the basis of a self electrostatic capacitance of the electrode of the first group; concurrently supply the touch detection driving signal to the electrode of the second group; and conduct touch detection on the basis of a self electrostatic capacitance of the electrode of the second group.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a display device with a touch detection function capable of detecting an external proximity object and a control method.

  In recent years, a so-called touch panel called a touch detection device capable of detecting an external proximity object has attracted attention. The touch panel is mounted on a display device such as a liquid crystal display device or integrated with the display device and used as a display device with a touch detection function. The display device with a touch detection function displays various button images and the like on the display device, thereby enabling information input using the touch panel as a substitute for a normal mechanical button.

  In the following Patent Document 1, a common electrode for display is also used as a touch detection electrode, and a capacitance is formed between the common electrode and the sensor detection electrode. There is described a display device with a touch sensor that performs touch detection by utilizing change caused by contact.

JP 2009-244958 A

  In a display device with a touch detection function that also uses a common electrode for display as a touch detection electrode, it is necessary to divide the image display period and the touch detection period, so it is necessary to shorten the image display period by the touch detection period. is there. When the image display period is shortened, the image quality is lowered or the power consumption is increased. Therefore, it is preferable to lengthen the image display period from the viewpoint of suppressing image quality deterioration or power consumption. Further, when the image display period and the touch detection period are divided, the current or voltage is switched at the boundary between the image display period and the touch detection period, so that sound is generated from a member (for example, a capacitor) that supplies the current or voltage. Invite so-called sound. Therefore, it is preferable that a plurality of image display periods are continued from the viewpoint of suppressing sound generation.

  An object of the present invention is to provide a display device with a touch detection function and a control method capable of extending an image display period.

  The display device with a touch detection function of one embodiment of the present invention includes a first group of electrodes extending along a first direction and a second direction extending along a second direction intersecting the first direction. A first operation mode for performing touch detection for displaying an image at a first frame frequency and detecting contact or proximity of an object to be detected; a touch detection unit including a group of electrodes; a display unit for displaying an image; And a second operation mode for displaying an image at a second frame frequency different from the first frame frequency and performing touch detection. The control unit sequentially supplies the touch detection drive signal to the first group of electrodes in the touch detection period of the first operation mode, and sets the mutual capacitance between the first group of electrodes and the second group of electrodes. Touch detection is performed based on the touch detection period. In the touch detection period of the second operation mode, touch detection drive signals are supplied to the first group of electrodes all at once, and touch detection is performed based on the self-capacitance of the first group of electrodes The touch detection drive signal is simultaneously supplied to the second group of electrodes, and touch detection is performed based on the self-capacitance of the second group of electrodes.

  A control method according to one embodiment of the present invention includes a first group of electrodes extending along a first direction, and a second group of electrodes extending along a second direction intersecting the first direction. , A display unit for displaying an image, and a display device with a touch detection function, wherein the image is displayed at the first frame frequency and the contact or proximity of the detected object is detected. In the touch detection period of the first operation mode in which the touch detection to be detected is performed, the touch detection drive signal is sequentially supplied to the first group of electrodes, and the mutual electrostatic capacitance between the first group of electrodes and the second group of electrodes is detected. In the touch detection period of the second operation mode in which touch detection is performed based on the capacity, an image is displayed at a second frame frequency different from the first frame frequency, and touch detection is performed, the first group of touch detection drive signals is transmitted. Supply all of the electrodes to the first group of electrodes Perform touch detection on the basis of capacity, by supplying simultaneously the touch detection drive signal to the electrodes of the second group, performing a touch detection based on the self-capacitance of the second group of electrodes.

FIG. 1 is a block diagram illustrating a configuration of a display device with a touch detection function according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration example of the touch detection unit and the display unit of the display device with a touch detection function. FIG. 3 is a diagram illustrating a display unit with a touch detection function. FIG. 4 is an explanatory diagram illustrating an example of the capacitance generated in the touch detection device. FIG. 5 is an explanatory diagram illustrating an example of an equivalent circuit of the touch detection device. FIG. 6 is a diagram illustrating an example of waveforms of the drive signal and the touch detection signal. FIG. 7 is an explanatory diagram illustrating an example of the capacitance generated in the touch detection device. FIG. 8 is an explanatory diagram illustrating an example of the capacitance generated in the touch detection device. FIG. 9 is an explanatory diagram illustrating a detection circuit. FIG. 10 is an explanatory diagram illustrating an equivalent circuit of the detection circuit. FIG. 11 is a diagram illustrating an example of a waveform of the detection circuit. FIG. 12 is a diagram illustrating an example of a module on which the display device with a touch detection function is mounted. FIG. 13 is a cross-sectional view illustrating a schematic cross-sectional structure of the display unit with a touch detection function. FIG. 14 is a circuit diagram illustrating a pixel arrangement of the display unit with a touch detection function. FIG. 15 is a perspective view illustrating a configuration example of the drive electrodes and the touch detection electrodes of the display unit with a touch detection function. FIG. 16 is a diagram illustrating a configuration of the touch detection control unit. FIG. 17 is a diagram illustrating an operation sequence in the first operation mode of the display device with a touch detection function. FIG. 18 is a diagram illustrating operation timings in the first operation mode of the display device with a touch detection function. FIG. 19 is a flowchart showing the operation in the first operation mode of the display device with a touch detection function. FIG. 20 is a diagram illustrating an operation sequence in the second operation mode of the display device with a touch detection function. FIG. 21 is a diagram illustrating an operation sequence in the second operation mode of the display device with a touch detection function. FIG. 22 is a diagram illustrating operation timings in the second operation mode of the display device with a touch detection function. FIG. 23 is a flowchart showing an operation in the second operation mode of the display device with a touch detection function. FIG. 24 is a diagram illustrating a configuration of a source driver, a source selector, and a liquid crystal display device. FIG. 25 is a diagram illustrating the timing of writing a pixel signal to a sub-pixel. FIG. 26 is a diagram illustrating operation timings in the second operation mode of the display device with a touch detection function.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined. It should be noted that the disclosure is merely an example, and those skilled in the art can easily conceive of appropriate modifications while maintaining the gist of the invention are naturally included in the scope of the present invention. In addition, the drawings may be schematically represented with respect to the width, thickness, shape, and the like of each part in comparison with actual aspects for the sake of clarity of explanation, but are merely examples, and the interpretation of the present invention is not limited. It is not limited. In addition, in the present specification and each drawing, elements similar to those described above with reference to the previous drawings are denoted by the same reference numerals, and detailed description may be omitted as appropriate.

(Embodiment)
FIG. 1 is a block diagram illustrating a configuration of a display device with a touch detection function according to an embodiment of the present invention.

  The display device with a touch detection function 1 according to the present embodiment includes a touch detection unit SE, a display unit DSP, and a control unit CTRL.

  The touch detection unit SE detects contact or proximity of the object OBJ to the input surface IS of the cover member CG. Specifically, the touch detection unit SE outputs, to the control unit CTRL, a signal value corresponding to the contact or proximity of each of the plurality of regions where the detected object OBJ overlaps in the direction perpendicular to the input surface IS. Note that the touch detection unit SE may have the input surface IS without arranging the cover member CG.

  The detected object OBJ may be a first type of object that deforms in contact with the input surface IS, or does not deform in contact with the input surface IS, or is relatively in comparison with the first type of object. The second type may be less deformed. The first type is exemplified by a finger, but is not limited thereto. Examples of the second type include, but are not limited to, resin or metal stylus pens.

  The number of detected objects that can be detected by the touch detection unit SE is not limited to one. The touch detection unit SE may be capable of detecting two or more objects to be detected.

  The touch detection unit SE is exemplified by a capacitive sensor. Examples of the capacitance method include a mutual (mutual) capacitance method and a self (self) capacitance method.

  The display unit DSP displays an image toward the input surface IS side. The display unit DSP is exemplified by a liquid crystal display device or an organic EL (Electro-Luminescence) display device, but is not limited thereto.

  The touch detection unit SE and the display unit DSP may be an integrated so-called in-cell type. Further, the touch detection unit SE and the display unit DSP may be a so-called on-cell type in which the touch detection unit SE is mounted on the display unit DSP.

  The control unit CTRL controls the display unit DSP to display an image on the display unit DSP, and controls the touch detection unit SE to cause the touch detection unit SE to perform touch detection.

  The control unit CTRL includes a display control unit 11, a touch detection control unit 40, and a host HOST.

  The display control unit 11 is exemplified by an IC chip mounted on the glass substrate of the display unit DSP. The touch detection control unit 40 is exemplified by an IC chip mounted on a printed circuit board (for example, a flexible printed circuit board) connected to the glass substrate of the display unit DSP. The host HOST is exemplified by a CPU (Central Processing Unit). The display control unit 11, the touch detection control unit 40, and the host HOST cooperate to control the touch detection unit SE and the display unit DSP.

  The display device with a touch detection function 1 performs image display and touch detection at a first operation mode in which image display and touch detection are performed at a first frame frequency, and at a second frame frequency different from the first frame frequency. A second operation mode.

  The case where the second frame frequency is lower than the first frame frequency is exemplified. When the second frame frequency is lower than the first frame frequency, the second frame frequency is exemplified as 0.5 times the first frame frequency, but is not limited thereto. The second frame frequency may be 0.75 times, 0.25 times, or the like of the first frame frequency.

  Moreover, the case where the second frame frequency is higher than the first frame frequency is exemplified. When the second frame frequency is higher than the first frame frequency, the second frame frequency is exemplified by twice the first frame frequency, but is not limited thereto. The second frame frequency may be 1.5 times or 2.5 times the first frame frequency.

  The host HOST outputs a mode signal Mode indicating whether to operate in the first operation mode or the second operation mode to the display control unit 11 and the touch detection control unit 40. When the mode signal Mode is at the first level (for example, low level), it indicates that the operation is performed in the first operation mode. When the mode signal Mode is at the second level (for example, high level), the second signal is Indicates that it operates in the operation mode.

  In addition, the host HOST outputs the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, and the video signal Vdisp to the display control unit 11. The display control unit 11 displays an image based on the mode signal Mode, the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, and the video signal Vdisp supplied from the host HOST. Further, the display control unit 11 outputs a count value signal Count obtained by counting the horizontal synchronization signal Hsync supplied from the host HOST to the touch detection control unit 40.

  The touch detection control unit 40 performs touch detection based on the mode signal Mode supplied from the host HOST and the count value signal Count supplied from the display control unit 11, and outputs a touch data signal TP-Data including touch coordinates to the host HOST. Output to.

The communication between the host HOST, the display control unit 11 and the touch detection control unit 40 is exemplified by I ² C (Inter-Integrated Circuit) or SPI (Serial Peripheral Interface).

  Hereinafter, specific configuration examples of the touch detection unit SE and the display unit DSP will be described. However, these configuration examples are examples, and the present invention is not limited to these configuration examples.

  FIG. 2 is a block diagram illustrating a configuration example of the touch detection unit and the display unit of the display device with a touch detection function. The display device with a touch detection function 1 shown in FIG. 2 is a device that detects the coordinates of an object to be detected OBJ by a so-called capacitance method.

  The display device 1 with a touch detection function includes a display unit 10 with a touch detection function, a display control unit 11, a gate driver 12, a source driver 13, a source selector 13S, a drive electrode driver 14, and a touch detection control unit 40. And including.

  The display unit 10 with a touch detection function is a so-called in-cell type device in which a capacitive touch detection device 30 is integrated in a liquid crystal display device 20 using a liquid crystal display element as a display element. The integration of the capacitive touch detection device 30 into the liquid crystal display device 20 means that, for example, some members such as a substrate and electrodes used as the liquid crystal display device 20 and the touch detection device 30 are integrated. And a part of a member such as a substrate or an electrode used as a substrate.

  The liquid crystal display device 20 corresponds to the display unit DSP of FIG. The touch detection device 30 corresponds to the touch detection unit SE in FIG.

  The display unit with a touch detection function 10 is a so-called on-cell type device in which a capacitive touch detection device 30 is mounted above a liquid crystal display device 20 using a liquid crystal display element as a display element. May be. In the case of an on-cell type device, the touch detection device 30 may be provided immediately above the liquid crystal display device 20, or the touch detection device 30 is provided above another layer instead of directly above the liquid crystal display device 20. It may be done.

  In this configuration example, the liquid crystal display device 20 is employed as the display unit DSP, but the display unit DSP may be configured to employ an organic EL element. In this case, one of the anode and the cathode forming the organic EL element may be a drive electrode COML related to touch detection described later.

  As will be described later, the liquid crystal display device 20 is a device that performs scanning by sequentially scanning one horizontal line at a time in accordance with a scanning signal Vscan supplied from the gate driver 12.

  FIG. 3 is a diagram illustrating a display unit with a touch detection function. In the present embodiment, the display unit with a touch detection function 10 has 300 horizontal lines. The 300 horizontal lines are divided into 10 units from the first unit to the tenth unit. Each of the first unit to the tenth unit has 30 horizontal lines.

  Referring to FIG. 2 again, the display control unit 11 includes a gate driver 12, a source driver 13, and a drive electrode based on the mode signal Mode, the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, and the video signal Vdisp supplied from the host HOST. Control signals are supplied to the driver 14 and the touch detection control unit 40, respectively, and control is performed so that they operate in cooperation.

  The control unit CTRL in the present disclosure includes a display control unit 11, a gate driver 12, a source driver 13, and a drive electrode driver 14.

  The display control unit 11 includes a memory 11A. The memory 11A stores a video signal Vdisp supplied from the host HOST for each horizontal line in synchronization with the horizontal synchronization signal Hsync. The memory 11A is exemplified by a RAM (Random Access Memory). The memory 11A may have a storage capacity for storing the video signals Vdisp of a plurality of horizontal lines.

  The display control unit 11 includes an internal horizontal synchronization signal generation unit 11B. The internal horizontal synchronization signal generator 11B generates an internal horizontal synchronization signal Int-Hsync based on the mode signal Mode, the vertical synchronization signal Vsync, and the horizontal synchronization signal Hsync supplied from the host HOST. The internal horizontal synchronization signal generation unit 11B includes, for example, an oscillator, and generates the internal horizontal synchronization signal Int-Hsync using the oscillator.

  The display control unit 11 includes a delay circuit 11C. The delay circuit 11C outputs an internal vertical synchronization signal Int-Vsync obtained by delaying the vertical synchronization signal Vsync supplied from the host HOST.

  The display control unit 11 includes a reset signal output unit 11D. The reset signal output unit 11D outputs a reset signal Reset in synchronization with the internal vertical synchronization signal Int-Vsync.

  The display control unit 11 includes a counter 11E. The counter 11E counts the horizontal synchronization signal Hsync and outputs a count value signal Count indicating the count value. The counter 11E starts counting the horizontal synchronization signal Hsync using the internal vertical synchronization signal Int-Vsync as a trigger. The counter 11E resets the count value by the reset signal Reset.

  The display control unit 11 includes a display panel control unit 11F. The display panel control unit 11F controls the gate driver 12, the source driver 13, and the drive electrode driver 14. When the count value signal Count supplied from the counter 11E reaches a predetermined value in response to the mode signal Mode supplied from the host HOST, the display panel control unit 11F synchronizes with the internal horizontal synchronization signal Int-Hsync, From a video signal Vdisp for one horizontal line in the memory 11A, a pixel signal Vsig obtained by time-division multiplexing pixel signals Vpix of a plurality of subpixels SPix of the liquid crystal display device 20 is generated and output to the source driver 13.

  The gate driver 12 sequentially selects one horizontal line as a display driving target of the display unit 10 with a touch detection function based on a control signal supplied from the display panel control unit 11F.

  The source driver 13 supplies the pixel signal Vpix to each pixel Pix (subpixel SPix) of the display unit with a touch detection function 10 based on the control signal supplied from the display panel control unit 11F. For example, 6-bit R (red), G (green), and B (blue) image signals Vsig are supplied to the source driver 13.

  The source driver 13 receives the image signal Vsig from the display panel control unit 11F and outputs it to the source selector 13S. Further, the source driver 13 generates switch control signals VselA and VselB, which will be described later, necessary for separating the pixel signal Vpix multiplexed on the image signal Vsig, and outputs it to the source selector 13S together with the pixel signal Vpix. The source selector 13S can reduce the number of wires between the source driver 13 and the display panel control unit 11F. The source selector 13S may not be provided. Further, a part of the source driver 13 may be controlled by the display panel control unit 11F, or only the source selector 13S may be arranged.

  The drive electrode driver 14 supplies a display drive signal Vcomd, which is a display voltage, to a drive electrode COML (to be described later) of the display unit 10 with a touch detection function based on a control signal supplied from the display panel control unit 11F.

  When the count value signal Count supplied from the counter 11E reaches a predetermined value in accordance with the mode signal Mode supplied from the host HOST, the touch detection control unit 40 uses the mutual capacitance method or the self-capacitance method. Based on the basic principle of touch detection, a touch drive signal Vcomtm, Vcomts 1 or Vcomts 2 is output to the touch detection device 30. The touch detection device 30 operates based on the basic principle of mutual capacitance type or self-capacitance type touch detection, and outputs a touch detection signal Vdetm, Vdets1 or Vdets2 to the touch detection control unit 40. The touch detection control unit 40 performs touch detection based on the touch detection signal Vdetm, Vdets1, or Vdets2 supplied from the touch detection device 30, and outputs a touch data signal TP-DATA including touch coordinates to the host HOST. The touch detection control unit 40 includes a self switch 40A, a selector 40B, a touch driver 40C, and a controller 40D. First, the basic principle of mutual capacitance type and self-capacitance type touch detection will be described, and then the self switch 40A, selector 40B, touch driver 40C and controller 40D will be described.

  With reference to FIG. 4 to FIG. 6, the basic principle of mutual capacitance type touch detection of the display device 1 with a touch detection function of the present embodiment will be described.

  FIG. 4 is an explanatory diagram illustrating an example of the capacitance generated in the touch detection device. FIG. 5 is an explanatory diagram illustrating an example of an equivalent circuit of the touch detection device. FIG. 6 is a diagram illustrating an example of waveforms of the drive signal and the touch detection signal. FIG. 5 also shows the detection circuit.

  For example, as shown in FIG. 4, the capacitive element C <b> 1 includes a pair of electrodes, a drive electrode E <b> 1, and a touch detection electrode E <b> 2 that are disposed to face each other with the dielectric D interposed therebetween. As shown in FIG. 5, one end of the capacitive element C1 is connected to an AC signal source (drive signal source) S, and the other end is connected to a voltage detector (touch detection unit) DET. The voltage detector DET is an integration circuit included in the touch detection control unit 40, for example.

  When an AC rectangular wave Sg having a predetermined frequency (for example, about several kHz to several hundred kHz) is applied from the AC signal source S to the drive electrode E1 (one end of the capacitive element C1), the touch detection electrode E2 (in addition to the capacitive element C1) An output waveform (touch detection signal Vdet) as shown in FIG. 6 appears through the voltage detector DET connected to the (end) side. The AC rectangular wave Sg corresponds to a touch drive signal Vcomtm, which will be described later, input from the touch detection control unit 40.

In a state where the finger is not in contact with or in close proximity (non-contact state), as shown in FIGS. 4 and 5, a current I ₀ corresponding to the capacitance value of the capacitive element C1 flows along with charging / discharging of the capacitive element C1. . The voltage detector DET shown in FIG. 5 converts the fluctuation of the current I ₀ corresponding to the AC rectangular wave Sg into a fluctuation of voltage (solid line waveform V ₀ (see FIG. 6)).

  On the other hand, in a state where the finger is in contact with or in proximity (contact state), the capacitance formed by the finger is in contact with or in the vicinity of the touch detection electrode E2, so that the drive electrode E1 and the touch detection electrode E2 Capacitance for the fringe in between is blocked. For this reason, the capacitive element C1 acts as a capacitive element having a capacitance value smaller than the capacitance value in the non-contact state. And the electric current which fluctuates according to the change of the capacitive element C1 flows.

As shown in FIG. 6, the voltage detector DET converts a current fluctuation according to the AC rectangular wave Sg into a voltage fluctuation (dotted line waveform V ₁ ). In this case, the waveform V ₁ has a smaller amplitude than the waveform V ₀ described above. As a result, the absolute value | ΔV | of the voltage difference between the waveform V ₀ and the waveform V ₁ changes according to the influence of a conductor that is in contact with or close to the outside such as a finger. Note that the voltage detector DET accurately detects the absolute value | ΔV | of the voltage difference between the waveform V ₀ and the waveform V ₁ , so that the capacitance of the capacitor is adjusted according to the frequency of the AC rectangular wave Sg by switching in the circuit. More preferably, the operation is provided with a period Res for resetting charging and discharging.

  The touch detection device 30 shown in FIG. 2 performs mutual electrostatic capacitance type touch detection by sequentially scanning one horizontal line at a time in accordance with the touch drive signal Vcomtm supplied from the touch detection control unit 40.

  With reference to FIG. 7 to FIG. 11, the basic principle of the self-capacitance type touch detection of the display device 1 with a touch detection function of the present embodiment will be described.

  7 and 8 are explanatory diagrams illustrating examples of capacitance generated in the touch detection device. FIG. 9 is an explanatory diagram illustrating a detection circuit. FIG. 10 is an explanatory diagram showing an equivalent circuit of the detection circuit of FIG. FIG. 11 is a diagram illustrating an example of a waveform of the detection circuit of FIG.

  First, as shown in FIG. 7, the electrode TL is connected to the power supply voltage Vcc by the switch 201. The electrode TL has a capacitance C3, a charge flows from the power supply potential Vcc to the electrode TL in the direction of the arrow 203, and the electrode TL is charged with a charge according to the capacitance C3.

  Next, as shown in FIG. 8, the electrode TL is connected to the detection circuit 202 by the switch 201, and the charge charged in the electrode TL flows to the detection circuit 202 in the direction of the arrow 204. The detection circuit 202 can detect the capacitance C3 of the electrode TL by measuring the charge flowing in from the electrode TL.

  Next, a case where a finger contacts or approaches the electrode TL will be described. As shown in FIG. 7, when the finger is in contact with or close to the electrode TL, the capacitance C2 of the finger is added to the capacitance C3 of the electrode TL. Therefore, when the electrode TL is connected to the power supply voltage Vcc by the switch 201, a charge flows from the power supply potential Vcc to the electrode TL in the direction of the arrow 203, and the electrode TL and the finger are charged according to the capacitances C3 and C2. Charged.

  Next, as shown in FIG. 8, the electrode TL is connected to the detection circuit 202 by the switch 201, and the charge charged in the electrode TL and the finger flows in the direction of the arrow 204 to the detection circuit 202. The detection circuit 202 can detect the capacitance between the electrode TL and the finger by measuring the charge flowing from the electrode TL and the finger.

  FIG. 9 is an explanatory diagram illustrating a detection circuit. Hereinafter, with reference to FIG. 9, the measurement procedure of the capacitance Cx of the electrode TL will be described.

  Step 1: First, the switch 207 is turned on, the switches 206 and 208 are turned off, and the series circuit of the resistor Rc and the capacitor Cc is connected between the power supply voltage Vcc and the ground potential to charge the capacitor Cc.

  Step 2: Next, all the switches 206 to 208 are turned off. The charge of the capacitor Cc is maintained.

  Step 3: Next, the switches 206 and 208 are turned on for a certain time, and the connection point between the capacitor Cx and the capacitor Cr and the connection point between the capacitor Cr and the resistor Rc are grounded. While all the charges in the capacitors Cx and Cr are discharged, a part of the charge in the capacitor Cc is discharged through the resistor Rc.

  Step 4: Next, all the switches 206 to 208 are turned off. The charge of the capacitor Cc moves to the capacitors Cx and Cr.

  Step 5: The comparator 205 compares the terminal voltage Vx of the capacitor Cx with the reference voltage Vref. As shown in FIG. 10, the terminal voltage Vc of the capacitor Cc at this time is the sum of the terminal voltage Vr of the capacitor Cr and the terminal voltage Vx of the capacitor Cx.

The relationship between the voltages Vc, Vr, Vx and the capacitors Cc, Cr, Cx can be expressed as the following equation.
Vc = Vr + Vx (1)
Vr: Vx = 1 / Cr: 1 / Cx (2)
Vx = Cr / (Cr + Cx) × Vc (3)

  Steps 3 to 5 are repeated until Vx <Vref. As indicated by the above formula (3), when the capacitance Cx increases as the finger contacts or approaches the electrode TL, the number of discharge cycles (the number of repetitions) until the condition Vx <Vref is satisfied decreases. Finger touch / non-touch can be determined by the number of discharge cycles.

  In FIG. 11, a period t20 is a period in which the finger is not in contact with or in proximity to the electrode TL, and a period t21 is a period in which the finger is in contact with or in proximity to the electrode TL. In FIG. 11, the bar graph represents the voltage Vx, and the line graph represents the voltage Vc.

  As Steps 3 to 5 are repeated, the voltage Vc gradually decreases. The voltage Vx is expressed by the above formula (3).

  When the finger contacts or approaches the electrode TL and the capacitance Cx increases, the number of discharge cycles (the number of repetitions) until Vx <Vref is reduced.

  When the finger is not in contact with or close to the electrode TL, the number of discharge cycles (repetition count) in the period t41 from the measurement start time t31 to t32 where Vx <Vref is eight. On the other hand, when the finger is in contact with or close to the electrode TL, the number of discharge cycles (the number of repetitions) in the period t42 from the measurement start time t33 to t34 where Vx <Vref is six.

  Thus, the detection circuit 202 can determine whether or not the finger is in contact with or close to the electrode TL by measuring the number of discharge cycles (the number of repetitions) until Vx <Vref.

  FIG. 12 is a diagram illustrating an example of a module on which the display device with a touch detection function is mounted. The display device with a touch detection function 1 includes a first substrate (for example, the pixel substrate 2) and a printed circuit board (for example, a flexible printed circuit board) T.

  The pixel substrate 2 has a first insulating substrate (for example, a TFT substrate 21). The TFT substrate 21 is, for example, a glass substrate or a film substrate. A driving IC chip (for example, COG (Chip On Glass) 19) is mounted on the TFT substrate 21. Further, the display area Ad of the liquid crystal display device 20 and the frame Gd are formed on the pixel substrate 2 (TFT substrate 21).

  The COG 19 is an IC chip that is a driver mounted on the TFT substrate 21, and is a control device that incorporates each circuit necessary for display operation, such as the display control unit 11 shown in FIG. The drive electrode driver 14 is formed on the TFT substrate 21.

  The display device with a touch detection function 1 may incorporate circuits such as the gate driver 12 and the drive electrode driver 14 in the COG 19. The COG 19 is merely a form of mounting and is not limited to this. For example, a configuration having the same function as the COG 19 may be mounted on the flexible printed circuit board T as COF (Chip On Film or Chip On Flexible).

  The display device with a touch detection function 1 is provided with a plurality of drive electrodes COML and a plurality of touch detection electrodes TDL in a region overlapping the display region Ad. The plurality of drive electrodes COML and the plurality of touch detection electrodes TDL are formed so as to cross three-dimensionally in the direction perpendicular to the surface of the TFT substrate 21. The plurality of drive electrodes COML extend, for example, in the X direction along the short side of the display area Ad, and the plurality of touch detection electrodes TDL extend, for example, in the Y direction along the long side of the display area Ad. ing.

  When performing the mutual capacitance type touch detection operation, the touch detection control unit 40 sequentially supplies the touch drive signal Vcomtm to each of the plurality of drive electrodes COML one horizontal line at a time. The touch detection electrodes TDL output the touch detection signal Vdetm to the touch detection control unit 40 each time the touch drive signal Vcomtm is supplied.

  When performing the self-capacitance type touch detection operation, the touch detection control unit 40 supplies the touch drive signal Vcoms1 to the plurality of drive electrodes COML all at once. The plurality of drive electrodes COML output the touch detection signal Vdets1 to the touch detection control unit 40 all at once.

  Further, when performing the self-capacitance type touch detection operation, the touch detection control unit 40 supplies the touch drive signal Vcoms2 to the plurality of touch detection electrodes TDL all at once. The plurality of touch detection electrodes TDL simultaneously output the touch detection signal Vdets2 to the touch detection control unit 40.

  The plurality of touch detection electrodes TDL and the plurality of drive electrodes COML are connected to a touch IC 49 mounted on the flexible printed circuit board T connected to the short side of the display device with a touch detection function 1. The touch IC 49 is an IC chip that is a driver mounted on the flexible printed circuit board T, and is a control device that incorporates each circuit necessary for the touch operation, such as the touch detection control unit 40 illustrated in FIG. As described above, the touch IC 49 is mounted on the flexible printed circuit board T, and is connected to the plurality of touch detection electrodes TDL and the plurality of drive electrodes COML. The flexible printed board T may be a terminal and is not limited to a board. In this case, the touch IC 49 is provided outside the module. The touch IC 49 is not limited to being disposed on the flexible printed circuit board T, but may be disposed on the TFT substrate 21 or the second insulating substrate 31 described later.

  In this configuration example, the touch IC 49 is a control device incorporating the touch detection control unit 40, but some functions of the touch detection control unit 40 may be provided as functions of other MPUs.

  Specifically, some functions (for example, noise removal) among various functions such as A / D conversion and noise removal that can be provided as functions of the IC chip that performs touch detection control are provided separately from the touch IC 49. It may be implemented by a circuit such as an MPU. Further, when one IC chip as a driver (one chip configuration) is used, for example, the detection signal may be transmitted to the IC chip on the TFT substrate 21 via a wiring such as the flexible printed board T. .

  The source selector 13S is formed using a TFT element in the vicinity of the display area Ad on the TFT substrate 21. A large number of pixels Pix, which will be described later, are arranged in a matrix (matrix) in the display area Ad. The frame Gd is an area where the pixel Pix is not arranged when the surface of the TFT substrate 21 is viewed from the vertical direction.

  In this configuration example, the source selector 13 </ b> S is formed on the TFT substrate 21. The source selector 13S may be built in the COG 19.

  FIG. 13 is a cross-sectional view illustrating a schematic cross-sectional structure of the display unit with a touch detection function. FIG. 14 is a circuit diagram illustrating a pixel arrangement of the display unit with a touch detection function. The display unit 10 with a touch detection function includes a pixel substrate 2, a second substrate (for example, a counter substrate 3) disposed in a direction perpendicular to the surface of the pixel substrate 2, the pixel substrate 2, and the counter substrate 3. And a display function layer (for example, a liquid crystal layer 6) inserted between the two.

  The pixel substrate 2 includes a TFT substrate 21 as a circuit substrate, a plurality of pixel electrodes 22 arranged in a matrix on the TFT substrate 21, and a plurality of drives formed between the TFT substrate 21 and the pixel electrodes 22. The electrode COML and the insulating layer 24 that insulates the pixel electrode 22 and the drive electrode COML are included.

  The TFT substrate 21 includes a thin film transistor (TFT) element Tr of each subpixel SPix shown in FIG. 14, a pixel signal line SGL for supplying a pixel signal Vpix to each pixel electrode 22 shown in FIG. 13, and each TFT element Tr. Wiring such as a scanning signal line GCL for driving is formed. The pixel signal line SGL extends in a plane parallel to the surface of the TFT substrate 21, and supplies a pixel signal Vpix for displaying an image to the sub-pixel SPix. The subpixel SPix indicates a structural unit controlled by the pixel signal Vpix. The subpixel SPix is a region surrounded by the pixel signal line SGL and the scanning signal line GCL, and indicates a structural unit controlled by the TFT element Tr.

  As shown in FIG. 14, the liquid crystal display device 20 has a plurality of subpixels SPix arranged in a matrix. The subpixel SPix includes a TFT element Tr and a liquid crystal element LC. The TFT element Tr is composed of a thin film transistor. In this example, the TFT element Tr is composed of an n-channel MOS (Metal Oxide Semiconductor) TFT.

  One of the source and drain of the TFT element Tr is coupled to the pixel signal line SGL, the gate is coupled to the scanning signal line GCL, and the other of the source and drain is coupled to one end of the liquid crystal element LC. For example, the liquid crystal element LC has one end coupled to the drain of the TFT element Tr and the other end coupled to the drive electrode COML. In FIG. 13, the pixel electrode 22, the insulating layer 24, and the drive electrode COML are stacked in this order on the TFT substrate 21, but the present invention is not limited to this. The driving electrode COML, the insulating layer 24, and the pixel electrode 22 may be laminated on the TFT substrate 21 in this order, or the driving electrode COML and the pixel electrode 22 may be formed in the same layer with the insulating layer 24 interposed therebetween. .

  The subpixel SPix is coupled to another subpixel SPix belonging to the same row of the liquid crystal display device 20 by the scanning signal line GCL. The scanning signal line GCL is coupled to the gate driver 12, and the scanning signal Vscan is supplied from the gate driver 12.

  The subpixel SPix is coupled to another subpixel SPix belonging to the same column of the liquid crystal display device 20 by the pixel signal line SGL. The pixel signal line SGL is coupled to the source driver 13, and the pixel signal Vpix is supplied from the source driver 13 (source selector 13S).

  Further, the subpixel SPix is coupled to another subpixel SPix belonging to the same row of the liquid crystal display device 20 by the drive electrode COML. The drive electrode COML is coupled to the drive electrode driver 14, and a display drive signal Vcomd is supplied from the drive electrode driver 14. That is, in this example, a plurality of subpixels SPix belonging to the same row share one drive electrode COML.

  The direction in which the drive electrode COML in this configuration example extends is parallel to the direction in which the scanning signal line GCL extends. The direction in which the drive electrode COML extends is not limited to this. For example, the direction in which the drive electrode COML extends may be a direction parallel to the direction in which the pixel signal line SGL extends. Further, the direction in which the touch detection electrode TDL extends is not limited to the direction in which the pixel signal line SGL extends. The direction in which the touch detection electrode TDL extends may be a direction parallel to the direction in which the scanning signal line GCL extends.

  The gate driver 12 shown in FIG. 2 is formed in a matrix form on the liquid crystal display device 20 by applying the scanning signal Vscan to the gate of the TFT element Tr of the pixel Pix via the scanning signal line GCL shown in FIG. One row (one horizontal line) among the sub-pixels SPix is sequentially selected as a display drive target.

  The source driver 13 shown in FIG. 2 supplies the pixel signal Vpix to each subpixel SPix configuring one horizontal line sequentially selected by the gate driver 12 via the pixel signal line SGL shown in FIG. In these sub-pixels SPix, one horizontal line is displayed in accordance with the supplied pixel signal Vpix.

  The drive electrode driver 14 shown in FIG. 2 applies a display drive signal Vcomd, and drives the drive electrode COML for each block including a predetermined number of drive electrodes COML.

  As described above, in the liquid crystal display device 20, one horizontal line is sequentially selected by driving the gate driver 12 so that the scanning signal lines GCL are line-sequentially scanned in a time division manner. In the liquid crystal display device 20, the source driver 13 supplies the pixel signal Vpix to the subpixels SPix belonging to one horizontal line, so that display is performed for each horizontal line. When performing this display operation, the drive electrode driver 14 applies the display drive signal Vcomd to the block including the drive electrode COML corresponding to the one horizontal line.

  The liquid crystal layer 6 modulates light passing therethrough according to the state of the electric field. When the drive electrode COML is driven, a voltage corresponding to the pixel signal Vpix supplied to the pixel electrode 22 is applied to the liquid crystal layer 6 and an electric field is generated, so that the liquid crystal constituting the liquid crystal layer 6 exhibits orientation corresponding to the electric field. Thus, the light passing through the liquid crystal layer 6 is modulated.

  Thus, the pixel electrode 22 and the drive electrode COML function as a first electrode and a second electrode that generate an electric field in the liquid crystal layer 6. That is, the liquid crystal display device 20 functions as a display unit in which the display output content changes according to the electric charge applied to the first electrode and the second electrode. The pixel electrode 22 is the first electrode and the drive electrode COML is the second electrode, but the reverse is also possible. The pixel electrode 22 is disposed at least for each pixel Pix or subpixel SPix, and the drive electrode COML is disposed for at least each of the plurality of pixels Pix or subpixel SPix.

  In the present configuration example, as the liquid crystal display device 20, for example, a liquid crystal display device using a liquid crystal in a transverse electric field mode such as IPS (in-plane switching) including FFS (fringe field switching) is used. Note that alignment films may be provided between the liquid crystal layer 6 and the pixel substrate 2 and between the liquid crystal layer 6 and the counter substrate 3 shown in FIG.

  The liquid crystal display device 20 has a configuration corresponding to the horizontal electric field mode, but may have a configuration corresponding to another display mode. For example, the liquid crystal display device 20 has a configuration corresponding to a mode that mainly uses a vertical electric field generated between the main surfaces of the substrate, such as a TN (Twisted Nematic) mode, an OCB (Optically Compensated Bend) mode, and a VA (Vertical Aligned) mode. You may do it. In the display mode using the vertical electric field, for example, a configuration in which the pixel electrode 22 is provided on the pixel substrate 2 and the drive electrode COML is provided on the counter substrate 3 is applicable.

  The counter substrate 3 includes a second insulating substrate 31 and a color filter 32 formed on one surface of the second insulating substrate 31. A touch detection electrode TDL, which is a detection electrode of the touch detection device 30, is formed on the other surface of the second insulating substrate 31, and a polarizing plate 35 is disposed on the touch detection electrode TDL. .

  The mounting method of the color filter 32 may be a so-called color filter on array (COA) method in which the color filter 32 is formed on the pixel substrate 2 which is an array substrate.

  The color filter 32 shown in FIG. 13 periodically arranges color regions of color filters colored, for example, red (R), green (G), and blue (B), so that each subpixel SPix has R. , G, and B color areas 32R, 32G, and 32B are associated with each other, and the color areas 32R, 32G, and 32B constitute a pixel Pix.

  The pixels Pix are arranged in a matrix along a direction parallel to the scanning signal line GCL and a direction parallel to the pixel signal line SGL, and forms a display area Ad. The color filter 32 faces the liquid crystal layer 6 in a direction perpendicular to the TFT substrate 21. In this way, the sub-pixel SPix can perform single color display.

  The color filter 32 may be a combination of other colors as long as it is colored in a different color. Further, the color filter 32 may be omitted. As described above, there may be a region where the color filter 32 does not exist, that is, a sub-pixel SPix that is not colored. Further, the number of subpixels SPix included in the pixel Pix may be four or more.

  FIG. 15 is a perspective view illustrating a configuration example of the drive electrodes and the touch detection electrodes of the display unit with a touch detection function. The drive electrode COML according to the present embodiment functions as a drive electrode of the liquid crystal display device 20 and also functions as a drive electrode of the touch detection device 30.

  The drive electrode COML faces the pixel electrode 22 in the direction perpendicular to the surface of the TFT substrate 21. The touch detection device 30 includes a plurality of drive electrodes COML provided on the pixel substrate 2 and a plurality of touch detection electrodes TDL provided on the counter substrate 3.

  The touch detection electrode TDL is composed of a striped electrode pattern extending in a direction crossing the extending direction of the electrode pattern of the drive electrode COML. The touch detection electrode TDL faces the drive electrode COML in a direction perpendicular to the surface of the TFT substrate 21. Each electrode pattern of the touch detection electrode TDL and the drive electrode COML is connected to the touch detection control unit 40.

  The electrode pattern in which the drive electrode COML and the touch detection electrode TDL intersect with each other generates capacitance at the intersection. The touch detection device 30 performs touch detection from the touch detection electrode TDL by applying a touch drive signal Vcomtm to the drive electrode COML from the touch detection control unit 40 when performing mutual electrostatic capacitance type touch detection. A signal Vdetm is output to the touch detection control unit 40 to perform touch detection.

  That is, the drive electrode COML corresponds to the drive electrode E1 in the basic principle of the mutual capacitance type touch detection shown in FIGS. 4 to 6, and the touch detection electrode TDL corresponds to the touch detection electrode E2. The touch detection device 30 detects a touch according to this basic principle.

  As described above, the touch detection device 30, when performing mutual electrostatic capacitance type touch detection, includes either the first electrode or the second electrode (for example, the drive electrode COML as the second electrode). It has a touch detection electrode TDL that forms a capacitance, and performs touch detection based on a change in mutual capacitance.

  The electrode pattern in which the drive electrode COML and the touch detection electrode TDL intersect each other constitutes a mutual capacitive touch sensor in a matrix. Therefore, the touch detection control unit 40 can detect the position and the contact area where the detection object contacts or approaches by scanning the entire input surface of the touch detection device 30.

  That is, in the touch detection device 30, when the mutual electrostatic capacitance type touch detection is performed, the touch detection control unit 40 drives the drive electrodes COML so as to scan the drive electrodes COML line-sequentially in time division. Accordingly, the drive electrodes COML are sequentially selected in the scan direction Scan. Then, the touch detection device 30 outputs a touch detection signal Vdetm from the touch detection electrode TDL.

  In the touch detection device 30, when performing self-capacitance type touch detection using the drive electrode COML, the touch detection signal is applied to the drive electrode COML from the touch detection controller 40, thereby driving the touch detection device 30. The touch detection signal Vdets1 is output from the electrode COML, and touch detection is performed.

  That is, the drive electrode COML corresponds to the electrode TL in the basic principle of the self-capacitance type touch detection shown in FIGS. The touch detection device 30 detects a touch according to this basic principle.

  As described above, when performing the self-capacitance type touch detection using the drive electrode COML, the touch detection device 30 performs touch detection based on the change in the self-capacitance of the drive electrode COML. The display device with a touch detection function 1 can detect the Y coordinate of an object to be detected in the self-capacitance type touch detection using the drive electrode COML.

  When performing self-capacitance type touch detection using the drive electrode COML, the touch detection control unit 40 can transmit the touch drive signal Vcomts1 to all the drive electrodes COML at the same time, and touch from all the drive electrodes COML. The detection signal Vdets1 can be received all at once. Accordingly, the time required for the display device 1 with a touch detection function to perform the self-capacitance type touch detection is relatively larger than the time required to perform the mutual capacitance type touch detection for scanning one horizontal line at a time. Short.

  In the touch detection device 30, when performing the self-capacitance type touch detection using the touch detection electrode TDL, the touch detection control unit 40 applies the touch drive signal Vcomts2 to the touch detection electrode TDL. A touch detection signal Vdets2 is output from the touch detection electrode TDL to perform touch detection.

  That is, the touch detection electrode TDL corresponds to the electrode TL in the basic principle of the self-capacitance type touch detection shown in FIGS. The touch detection device 30 detects a touch according to this basic principle.

  As described above, when performing the self-capacitance type touch detection using the touch detection electrode TDL, the touch detection device 30 performs touch detection based on the change in the self-capacitance of the touch detection electrode TDL. The display device with a touch detection function 1 can detect the X coordinate of an object to be detected in the self-capacitance type touch detection using the touch detection electrode TDL.

  When performing the self-capacitance type touch detection using the touch detection electrode TDL, the touch detection control unit 40 can transmit the touch drive signal Vcomts2 to all the touch detection electrodes TDL all at once, and all the touch detection electrodes The touch detection signal Vdets2 can be received simultaneously from the TDL. Accordingly, the time required for the display device 1 with a touch detection function to perform the self-capacitance type touch detection is relatively larger than the time required to perform the mutual capacitance type touch detection for scanning one horizontal line at a time. Short.

  The touch detection control unit 40 performs both the self-capacitance type touch detection using the drive electrode COML and the self-capacitance type touch detection using the touch detection electrode TDL, thereby detecting an object to be detected. X coordinate and Y coordinate can be detected.

  The touch detection control unit 40 may perform the self-capacitance type touch detection using the drive electrode COML and the self-capacitance type touch detection using the touch detection electrode TDL all at once or differently. It may be done at the timing. If the touch detection control unit 40 performs the self-capacitance touch detection using the drive electrode COML and the self-capacitance touch detection using the touch detection electrode TDL at the same time, The time required for capacitive touch detection can be shortened. If the touch detection control unit 40 performs self-capacitance touch detection using the drive electrode COML and self-capacitance touch detection using the touch detection electrode TDL at different timings, The peak of power used for self-capacitance touch detection can be kept low.

  Note that the touch detection electrode TDL or the drive electrode COML is not limited to a shape divided into a plurality of stripes. For example, the touch detection electrode TDL or the drive electrode COML may have a comb shape. Alternatively, the touch detection electrode TDL or the drive electrode COML may be divided into a plurality of pieces, and the shape of the slit dividing the drive electrode COML may be a straight line, a curve, or a polygonal shape.

  As an example of the operation method of the display device 1 with a touch detection function, the display device 1 with a touch detection function performs a touch detection operation (touch detection period) and a display operation (display operation period) in a time-sharing manner.

  The plurality of drive electrodes COML correspond to the first group of electrodes of the present invention, and the plurality of touch detection electrodes TDL correspond to the second group of electrodes of the present invention.

  FIG. 16 is a diagram illustrating a configuration of the touch detection control unit. The touch detection electrodes TDL-1, TDL-2,..., TDL-n are connected to the touch detection control unit 40. The drive electrodes COML-1, COML-2,..., COML-m are connected to the drive electrode driver 14 by an unillustrated switch or the like during an image display operation, and the switch or the like during a touch detection operation. Thus, the touch detection control unit 40 is connected.

  The above-described mode signal Mode is input to the touch detection control unit 40 from the host HOST shown in FIG. Based on the mode signal Mode, the touch detection control unit 40 switches between the mutual capacitance type touch detection operation and the self capacitance type touch detection operation. 1 is input to the touch detection control unit 40 from the display control unit 11 shown in FIG.

  As illustrated in FIG. 16, the touch detection control unit 40 applies the touch drive signal Vcomtm to the drive electrodes COML-1, COML-2,..., COML-m when performing mutual capacitance type touch detection. Each time a horizontal line is sequentially output and the touch drive signal Vcomtm is output, the touch detection signal Vdetm is received from the touch detection electrodes TDL-1, TDL-2, ..., TDL-n.

  When the touch detection control unit 40 performs the self-capacitance type touch detection using the drive electrodes COML-1, COML-2, ..., COML-m, the touch detection signal Vcomts1 is used as the drive electrode COML-1. , COML-2,..., COML-m are simultaneously output, and the touch detection signal Vdets1 is simultaneously received from the drive electrodes COML-1, COML-2,.

  When performing touch detection of the self-capacitance method using the touch detection electrodes TDL-1, TDL-2,..., TDL-n, the touch detection control unit 40 receives the touch drive signal Vcomts2 as the touch detection electrode TDL. -1, TDL-2,..., TDL-n are simultaneously output, and the touch detection signal Vdets2 is simultaneously received from the touch detection electrodes TDL-1, TDL-2,.

  The touch detection control unit 40 includes a self switch 40A, a selector 40B, a touch driver 40C, and a controller 40D.

  The operation of each part in the touch detection control unit 40 at the time of self-capacitance type touch detection using the drive electrodes COML-1, COML-2,..., COML-m will be described.

  When the mode signal Mode supplied from the host HOST represents the second operation mode (for example, high level), the controller 40D represents the self-capacitance type touch detection (for example, high level). -Control is output to the self switch 40A.

  Self switch 40A includes self block 40A1 and mutual block 40A2. The drive electrodes COML-1, COML-2,..., COML-m are branched and connected to the self block 40A1 and the mutual block 40A2.

  Self block 40A1 includes a plurality of switches. The plurality of switches are turned on when the self-control signal Self-Control supplied from the controller 40D represents a self-capacitance type touch detection operation (for example, high level). When the plurality of switches in the self block 40A1 are turned on, the touch driver 40C and the drive electrodes COML-1, COML-2, ..., COML-m are brought into conduction.

  The controller 40D outputs a synchronization signal TSVD to the touch driver 40C. Upon receiving the synchronization signal TSVD, the touch driver 40C outputs a plurality of touch drive signals Vcomts1 to the self block 40A1 all at once.

  The plurality of switches in the self block 40A1 simultaneously transmit a plurality of touch drive signals Vcomts1 supplied from the touch driver 40C to the drive electrodes COML-1, COML-2,. A plurality of touch detection signals Vdets1 supplied from COML-1, COML-2,..., COML-m are simultaneously transmitted to the touch driver 40C.

  The touch driver 40C generates a touch data signal TP-DATA based on the plurality of touch detection signals Vdets1 supplied from the self block 40A1, and outputs the touch data signal TP-DATA to the controller 40D.

  The operation of each part in the touch detection control unit 40 at the time of touch detection of the self-capacitance method using the touch detection electrodes TDL-1, TDL-2,..., TDL-n will be described.

  When the mode signal Mode supplied from the host HOST represents the second operation mode (for example, high level), the controller 40D represents the self-capacitance type touch detection (for example, high level). -Control is output to the self switch 40A. This is to prevent the mutual capacitance type touch detection operation.

  The controller 40D outputs a synchronization signal TSVD to the touch driver 40C. When the touch driver 40C receives the synchronization signal TSVD, the touch driver 40C outputs a plurality of touch drive signals Vcomts2 to the touch detection electrodes TDL-1, TDL-2,.

  The touch driver 40C generates a touch data signal TP-DATA based on a plurality of touch detection signals Vdets2 supplied from the touch detection electrodes TDL-1, TDL-2,. Output to 40D.

  The operation of each unit in the touch detection control unit 40 at the time of mutual capacitance type touch detection will be described.

  When the mode signal Mode supplied from the host HOST represents the first operation mode (for example, low level), the controller 40D represents the mutual capacitance type touch detection (for example, low level). -Control is output to the self switch 40A. As a result, the plurality of switches in the self block 40A1 are turned off.

  Mutual block 40A2 includes a plurality of switches. The plurality of switches are turned on when the self-control signal Self-Control supplied from the controller 40D indicates a mutual capacitance type touch detection operation (for example, at a low level). When the plurality of switches in the mutual block 40A2 are turned on, the plurality of output terminals of the selector 40B and the drive electrodes COML-1, COML-2, ..., COML-m are brought into conduction.

  The controller 40D outputs a transmission electrode control signal Tx-Control designating one of the drive electrodes COML-1, COML-2, ..., COML-m to the input terminal of the selector 40B. As a result, the selector 40B conducts the specified one of the drive electrodes COML-1, COML-2,..., COML-m and the touch driver 40C.

  The touch driver 40C outputs a touch drive signal Vcomtm to the selector 40B. As a result, the touch drive signal Vcomtm is supplied to one designated electrode among the drive electrodes COML-1, COML-2, ..., COML-m.

  The touch driver 40C receives the touch detection signal Vdetm from the touch detection electrodes TDL-1, TDL-2, ..., TDL-n.

  The controller 40D sequentially designates one of the drive electrodes COML-1, COML-2, ..., COML-m. The touch driver 40C outputs a touch drive signal Vcomtm to the selector 40B and receives the touch detection signal Vdetm from the touch detection electrodes TDL-1, TDL-2,..., TDL-n each time. The touch driver 40C generates a touch data signal TP-DATA based on the touch detection signal Vdetm supplied from the touch detection electrodes TDL-1, TDL-2,..., TDL-n, and outputs the touch data signal TP-DATA to the controller 40D. .

<Outline of operation of display device with touch detection function>
In the in-cell type display device with a touch detection function, since some members are used for both image display and touch detection, it is necessary to separate the image display period and the touch detection period. Therefore, in the in-cell type display device with a touch detection function, the image display period needs to be shortened by the touch detection period.

  In an on-cell type display device with a touch detection function, it is desirable to divide an image display period and a touch detection period in order to prevent noise in image display from affecting touch detection. Therefore, it is desirable to shorten the image display period by the touch detection period even in the on-cell type display device with a touch detection function.

  When the image display period is shortened, the image quality is lowered or the power consumption is increased. Therefore, it is preferable to lengthen the image display period from the viewpoint of suppressing image quality deterioration or power consumption. In order to lengthen the image display period, it is necessary to shorten the touch detection period.

  Further, when the image display period and the touch detection period are divided, the current or voltage is switched at the boundary between the image display period and the touch detection period, so that sound is generated from a member (for example, a capacitor) that supplies the current or voltage. Invite so-called sound. Therefore, it is preferable that a plurality of image display periods are continued from the viewpoint of suppressing sound generation.

  The mutual capacitance type touch detection is compared with the self-capacitance type touch detection. In the mutual capacitance type touch detection, the electrodes are driven while scanning one horizontal line at a time, so that even if there are a plurality of detection objects, the coordinates of each of the plurality of detection objects can be detected appropriately. There are benefits. That is, the mutual capacitance type touch detection has an advantage of enabling multi-touch. On the other hand, the mutual capacitance type touch detection is driven while scanning the electrodes one horizontal line at a time. Has the disadvantage of becoming longer.

  Since the self-capacitance type touch detection drives a plurality of electrodes all at once, the time is relatively short compared to the mutual capacitance type touch detection in which the electrodes are driven while scanning one horizontal line at a time. There is a merit that On the other hand, the self-capacitance type touch detection drives a plurality of electrodes all at once, and therefore has a demerit that when there are a plurality of objects to be detected, the coordinates of the plurality of objects to be detected cannot be detected appropriately. . For example, when the first detected object touches the coordinates (X1, Y1) and the second detected object touches the coordinates (X2, Y2), the coordinates (X1, Y1) and (X2 , Y2), the touch is detected not only at the coordinates (X1, Y2) and (X2, Y1). That is, a ghost touch is detected at the coordinates (X1, Y2) and (X2, Y1). Accordingly, the self-capacitance type touch detection has a demerit that multi-touch cannot be made possible.

  Electronic devices using a display device with a touch detection function include applications that require multi-touch and applications that do not require multi-touch. The electronic device is exemplified by a smartphone or a tablet. An application requiring multi-touch is exemplified by a game application. Examples of applications that do not require multi-touch include a calculator application, a calendar application, an address book application, and a moving image reproduction application.

  Therefore, the display device with a touch detection function 1 according to the present embodiment performs mutual capacitance type touch detection in the first operation mode, and performs self-capacitance type touch detection in the second operation mode. The display device with a touch detection function 1 executes an application that requires multi-touch in the first operation mode, and executes an application that does not require multi-touch in the second operation mode. Thereby, the display device with a touch detection function 1 makes it possible to lengthen the image display period.

  Note that the display device with a touch detection function 1 shifts to the second operation mode when no touch is detected for a predetermined period in the first operation mode, and first when the touch is detected in the second operation mode. The operation mode may be changed to.

<Operation in First Operation Mode of Display Device with Touch Detection Function>
FIG. 17 is a diagram illustrating an operation sequence in the first operation mode of the display device with a touch detection function. FIG. 17 shows an operation sequence for one frame. As illustrated in FIG. 17, the display device with a touch detection function 1 sequentially performs control on ten units from the first unit to the tenth unit.

Display device with a touch detection function 1, during a period from the timing t ₀ to time t _1, the image display in the 30 horizontal lines included in the first unit starts, during a period from the timing t ₁ to timing t ₂ Then, the mutual capacitive touch detection is started on 30 horizontal lines included in the first unit.

Display device with a touch detection function 1, during a period from the timing t ₂ to time t _3, the image display in the 30 horizontal lines included in the second unit to start, during a period from the timing t ₃ to time t ₄ The touch detection of the mutual capacitance method at the 30 horizontal lines included in the second unit is started.

  Thereafter, similarly, the display device with a touch detection function 1 performs image display and touch detection up to the tenth unit.

  FIG. 18 is a diagram illustrating operation timings in the first operation mode of the display device with a touch detection function.

  In the present embodiment, the frame frequency in the first operation mode is 59.94 Hz, but is not limited to this.

One frame period T1, one starts at a timing _{t 10} of the falling of a vertical synchronization signal Vsync, a ends at timing _{t 17} of the falling edge of the next vertical synchronization signal Vsync. There is a start pouch period VBP at the beginning of the frame period T1, and an end pouch period VFP at the end of the frame period T1.

The host HOST at the timing _{t 10,} asserts a vertical synchronization signal Vsync. The host HOST at the timing _{t 11} after the start porch period VBP elapsed from the timing _{t 10,} it starts outputting the image signals Vdisp of 30 horizontal line included in the first unit. The host HOST outputs the image signal Vdisp to the memory 11A for each horizontal line in synchronization with the horizontal synchronization signal Hsync, and the memory 11A receives and stores the image signal Vdisp supplied from the host HOST. The period T2 is a transfer period of image signals Vdisp for 30 horizontal lines included in the first unit, and the period T3 is a transfer period of image signals Vdisp for 30 horizontal lines included in the second unit.

The delay circuit 11C at the timing _{t 11} after the delay time Delay elapses from the timing _{t 10,} asserts the internal vertical synchronizing signal Int-Vsync.

  In the first operation mode, the internal horizontal synchronization signal generation unit 11B generates and outputs an internal horizontal synchronization signal Int-Hsync having a frequency twice that of the horizontal synchronization signal Hsync. In addition, 2 times is an illustration and it is not limited to this. The frequency of the internal horizontal synchronization signal Int-Hsync may be 1.5 times or 2.5 times the frequency of the horizontal synchronization signal Hsync. The image display period needs to be shortened by as much as the touch detection period is secured. Therefore, it is exemplified that the frequency of the internal horizontal synchronization signal Int-Hsync is higher than the frequency of the horizontal synchronization signal Hsync.

Reset signal output unit 11D at a timing _{t 11} to the internal vertical synchronizing signal Int-Vsync is asserted, asserts the reset signal Reset. The counter 11E is reset to 0 when the reset signal Reset is asserted. Thereafter, the counter 11E counts the horizontal synchronization signal Hsync.

The display panel controller 11F, once turned A1 count value of the counter 11E is a predetermined value, at the timing t _12, starts the 30 image display of a horizontal line included in the first unit. The display panel control unit 11F displays an image for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 11} to the timing _{t 12} is the internal initiation porch period Int-VBP.

Touch detection control unit 40, once turned A2 count value of the counter 11E is a predetermined value at the timing t _13, the touch detection of the mutual capacitance method in 30 horizontal lines included in the first unit To start. The touch detection control unit 40 performs touch detection for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 12} to the timing _{t 13} is an image display period T5 of the first unit.

The display panel controller 11F, once turned A3 count value of the counter 11E is a predetermined value, at a timing t _14, starts the 30 image display of a horizontal line included in the second unit. The display panel control unit 11F displays an image for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 13} to the timing _{t 14} is a touch detection period T6 of the first unit. Further, the period from the timing _{t 12} to the timing _{t 14} is a control period T4 of the first unit.

  When the image display period T5 of the first unit is the same as the touch detection period T6 of the first unit, the frequency of the internal horizontal synchronization signal Int-Hsync is preferably twice the frequency of the horizontal synchronization signal Hsync. When the image display period T5 of the first unit is longer than the touch detection period T6 of the first unit, the frequency of the internal horizontal synchronization signal Int-Hsync is greater than and twice the frequency of the horizontal synchronization signal Hsync. It is better to make it smaller. When the image display period T5 of the first unit is shorter than the touch detection period T6 of the first unit, the frequency of the internal horizontal synchronization signal Int-Hsync is preferably larger than twice the frequency of the horizontal synchronization signal Hsync.

Touch detection control unit 40, once turned A4 count value of the counter 11E is a predetermined value, at a timing t _15, the touch detection of the mutual capacitance method in 30 horizontal lines included in the second unit To start.

Period from the timing _{t 14} to the timing _{t 15} is an image display period T8 of the second unit.

The display panel controller 11F, once turned A5 count value of the counter 11E is a predetermined value at the timing t _16, starts the 30 image display of a horizontal line included in the third unit. The display panel control unit 11F displays an image for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 15} to the timing _{t 16} is a touch detection period T9 of the second unit. Further, the period from the timing _{t 14} to the timing _{t 16} is the control period T7 of the second unit.

At the timing _{t 16,} the third unit control period T10 and the image display period T11 of the third unit starts, and at the timing _{t 17,} the touch detection period control period T12 and 10 units of the 10 units of T13 Ends.

Period from the timing _{t 17} to the timing _{t 18} to the internal vertical synchronizing signal Int-Vsync is asserted, the internal ends porch period Int-VFP.

  FIG. 19 is a flowchart showing the operation in the first operation mode of the display device with a touch detection function. In step S100, the display device with a touch detection function 1 selects one unit from the first unit to the tenth unit.

  In step S101, the display panel control unit 11F performs image display on one unit selected in step S100.

  In step S102, the touch detection control unit 40 performs touch detection in one unit selected in step S100.

  Next, the display device with a touch detection function 1 performs a process of returning the process to step S100 when the processes of all the units from the first unit to the tenth unit have not been completed (No in step S103). . In step S100, the display device with a touch detection function 1 selects the next unit. The display device with a touch detection function 1 ends the operation process in the first operation mode when the processes of all the units from the first unit to the tenth unit have been completed (Yes in step S103). .

<Operation in Second Operation Mode of Display Device with Touch Detection Function>
Next, the operation in the second operation mode of the display device with a touch detection function 1 will be described. FIG. 20 is a diagram illustrating an operation sequence in the second operation mode of the display device with a touch detection function. FIG. 20 shows an operation sequence for one frame. As shown in FIG. 20, the display device with a touch detection function 1 sequentially displays images on ten units from the first unit to the tenth unit, and the first unit to the tenth unit. After the image display of the 10 units up to is completed, the self-capacitance type touch detection is performed.

Display device with a touch detection function 1, during a period from the timing t ₂₀ to the timing t _21, starts image display of 30 horizontal lines included in the first unit.

Display device with a touch detection function 1, during a period from the timing t ₂₁ to the timing t _22, starts image display of 30 horizontal lines included in the second unit.

Display device with a touch detection function 1, at a timing t ₂₃ to the image display of the first 10 units is completed, performing a touch detection self capacitive. At this time, the display device with a touch detection function 1 supplies the touch drive signal Vcomts1 to the drive electrodes COML all at once to perform touch detection in the Y direction, and simultaneously supplies the touch drive signal Vcomts2 to the touch detection electrodes TDL. You may perform the touch detection of a X direction. Thereby, the display device 1 with a touch detection function can shorten the time required for the self-capacitance type touch detection.

The display device with a touch detection function 1 may perform touch detection in the X direction and touch detection in the Y direction at different timings. FIG. 21 is a diagram illustrating an operation sequence in the second operation mode of the display device with a touch detection function. FIG. 21 shows an operation sequence for one frame. As shown in FIG. 21, a touch detection function display device 1, at a timing t ₂₃ to the image display of the first 10 units is completed, performing a touch detection self capacitive in the X direction (or Y direction). Next, display device with a touch detection function 1, in the X direction (or Y direction) self capacitive touch detection timing t ₂₄ to the image display has been completed in the self-capacitance of the Y-direction (or X-direction) Perform touch detection. Thereby, the display device with a touch detection function 1 can suppress the peak of power used for the self-capacitance type touch detection to a low level.

<First Operation Timing of Second Operation Mode of Display Device with Touch Detection Function>
The operation timing in the second operation mode of the display device 1 with a touch detection function will be described. First, the operation timing when the frame frequency of the second operation mode is lower than the frame frequency of the first operation mode (for example, 59.94 Hz) (for example, 29.97 Hz) will be described first. The operation timing when the frame frequency of the second operation mode is higher than the frame frequency of the first operation mode (for example, 119.88 Hz) will be described.

  The application executed at the frame frequency (for example, 29.97 Hz) of the second operation mode is exemplified by a calculator application, a calendar application, or an address book application, but is not limited thereto.

  FIG. 22 is a diagram illustrating operation timings in the second operation mode of the display device with a touch detection function. FIG. 22 is a diagram illustrating operation timing when the frame frequency in the second operation mode is lower than the frame frequency (for example, 59.94 Hz) in the first operation mode (for example, 29.97 Hz). .

One frame period T21 is one starts at a timing _{t 30} of the falling of a vertical synchronization signal Vsync, a ends at timing _{t 37} of the falling edge of the next vertical synchronization signal Vsync. There is a start porch period VBP at the beginning of the frame period T21, and an end porch period VFP at the end of the frame period T21.

The host HOST at the timing _{t 30,} asserts a vertical synchronization signal Vsync. The host HOST at the timing _{t 31} after the start porch period VBP elapsed from the timing _{t 30,} it starts outputting the image signals Vdisp of 30 horizontal line included in the first unit. The host HOST outputs the image signal Vdisp to the memory 11A for each horizontal line in synchronization with the horizontal synchronization signal Hsync, and the memory 11A receives and stores the image signal Vdisp supplied from the host HOST. The period T22 is a transfer period of image signals Vdisp for 30 horizontal lines included in the first unit, and the period T23 is a transfer period of image signals Vdisp for 30 horizontal lines included in the second unit.

The delay circuit 11C at the timing _{t 31} after the delay time Delay elapses from the timing _{t 30,} asserts the internal vertical synchronizing signal Int-Vsync.

  In the second operation mode, the internal horizontal synchronization signal generation unit 11B generates and outputs an internal horizontal synchronization signal Int-Hsync having the same frequency as the horizontal synchronization signal Hsync. Note that the frequency of the internal horizontal synchronization signal Int-Hsync is the same as the frequency of the horizontal synchronization signal Hsync, and is not limited thereto. The frequency of the internal horizontal synchronization signal Int-Hsync may be 0.75 times or 0.8 times the frequency of the horizontal synchronization signal Hsync. The frequency of the internal horizontal synchronization signal Int-Hsync is exemplified as not more than one time the frequency of the horizontal synchronization signal Hsync.

Reset signal output unit 11D at a timing _{t 31} to the internal vertical synchronizing signal Int-Vsync is asserted, asserts the reset signal Reset. The counter 11E is reset to 0 when the reset signal Reset is asserted. Thereafter, the counter 11E counts the horizontal synchronization signal Hsync.

The display panel controller 11F, once turned B1 count value of the counter 11E is a predetermined value at the timing t _32, starts the 30 image display of a horizontal line included in the first unit. The display panel control unit 11F displays an image for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 31} to the timing _{t 32} is the internal initiation porch period Int-VBP.

The display panel controller 11F, once turned B2 count value of the counter 11E is a predetermined value, at a timing t _33, starts the 30 image display of a horizontal line included in the second unit. The display panel control unit 11F displays an image for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 32} to the timing _{t 33} is an image display period T24 of the first unit.

The display panel controller 11F, once turned B3 count value of the counter 11E is a predetermined value, at a timing t _34, starts the 30 image display of a horizontal line included in the third unit. The display panel control unit 11F displays an image for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 33} to the timing _{t 34} is an image display period T25 of the second unit.

At timing _{t 34,} the image display period T26 of the third unit starts at a timing _{t 35,} the image display period T27 of the first 10 units are completed.

Touch detection control unit 40, once turned B4 count value of the counter 11E is a predetermined value, at a timing t _35, performing a touch detection self capacitive. The touch detection control unit 40 supplies the touch drive signal Vcomts1 to the drive electrodes COML all at once to perform touch detection in the Y direction, and simultaneously supplies the touch drive signal Vcomts2 to the touch detection electrodes TDL to detect touch in the X direction. May be performed. Alternatively, the touch detection control unit 40 performs self-capacitance type touch detection in the X direction (or Y direction), and when the self-capacitance type touch detection in the X direction (or Y direction) ends, the Y direction. Self-capacitive touch detection in the (or X direction) may be performed.

Period from the timing _{t 35,} to the timing _{t 36} to the touch detection is completed, a touch detection period T28.

From the timing _{t 36,} the period from the timing _{t 38} to the internal vertical synchronizing signal Int-Vsync is asserted, the internal ends porch period Int-VFP.

  The length of the first unit image display period T24 (see FIG. 22) in the second operation mode and the length of the first unit image display period T5 (see FIG. 18) in the first operation mode. May be different. The length of the image display period T24 of the first unit in the second operation mode may be longer than the length of the image display period T5 of the first unit in the first operation mode.

  FIG. 23 is a flowchart showing an operation in the second operation mode of the display device with a touch detection function. In step S200, the display device with a touch detection function 1 selects one unit from the first unit to the tenth unit.

  In step S201, the display panel control unit 11F performs image display on one unit selected in step S200.

  Next, the display device with a touch detection function 1 performs a process of returning the process to step S200 when the processes of all the units from the first unit to the tenth unit have not been completed (No in step S202). . In step S200, the display device with a touch detection function 1 selects the next unit.

  When the processing of all the units from the first unit to the tenth unit has been completed (step S202, Yes), the touch detection control unit 40 performs self-capacitance type touch detection in step S203. .

  In the display device with a touch detection function 1, when the frequency of the internal horizontal synchronization signal Int-Hsync is the same as the horizontal synchronization signal Hsync, the internal end porch period Int-VFP is shortened by the touch detection period T28. Become. If the internal end porch period Int-VFP has a margin corresponding to the touch detection period T28, the display device with a touch detection function 1 shortens the internal end porch period Int-VFP by the touch detection period T28. Thus, the frequency of the internal horizontal synchronization signal Int-Hsync can be made the same as that of the horizontal synchronization signal Hsync.

  In the display device with a touch detection function 1, the transfer period of the image signal Vdisp of the first to tenth units is the same as the period obtained by adding the touch detection period to the image display period of the first to tenth units. Anyway.

  For example, the display device with a touch detection function 1 may make the frequency of the internal horizontal synchronization signal Int-Hsync relatively higher than the horizontal synchronization signal Hsync. In this way, the image display period T24 of the first unit is relatively shorter than the transfer period T22 of the image signal Vdisp of the first unit, and the image display period T25 of the second unit is the second unit. Becomes relatively shorter than the transfer period T23 of the image signal Vdisp. That is, the image display period of the first to tenth units is relatively shorter than the transfer period of the image signal Vdisp of the first to tenth units. Therefore, the display device with a touch detection function 1 assigns the difference between the transfer period of the image signal Vdisp of the first to tenth units and the image display period of the first to tenth units to the touch detection period T28. be able to.

  In order to make the frequency of the internal horizontal synchronization signal Int-Hsync relatively higher than the horizontal synchronization signal Hsync, the display device with a touch detection function 1 keeps the frequency of the horizontal synchronization signal Hsync as it is and maintains the internal horizontal synchronization signal. The frequency of Int-Hsync may be increased. Alternatively, the display device with a touch detection function 1 may leave the frequency of the internal horizontal synchronization signal Int-Hsync as it is in order to make the frequency of the internal horizontal synchronization signal Int-Hsync relatively higher than the horizontal synchronization signal Hsync. The frequency of the horizontal synchronization signal Hsync may be lowered. Alternatively, the display device with a touch detection function 1 lowers the frequency of the horizontal synchronization signal Hsync and sets the internal horizontal synchronization so that the frequency of the internal horizontal synchronization signal Int-Hsync is relatively higher than the horizontal synchronization signal Hsync. The frequency of the signal Int-Hsync may be increased.

  The display device with a touch detection function 1 shifts to the second operation mode when a predetermined application (for example, a calculator application, a calendar application, or an address book application) is executed, and an application other than the predetermined application (for example, , A game application) may be executed to transit to the first operation mode.

  Alternatively, the display device with a touch detection function 1 shifts to the second operation mode when no touch is detected for a predetermined period in the first operation mode, and first when the touch is detected in the second operation mode. The operation mode may be changed to.

[effect]
The display device 1 with a touch detection function has the following effects. The display device with a touch detection function 1 performs mutual capacitance type touch detection in the first operation mode, and performs self-capacitance type touch detection in the second operation mode. The time required for the self-capacitance type touch detection is relatively short compared to the mutual capacitance type touch detection. Accordingly, the display device with a touch detection function 1 can extend the image display period of each of the first to tenth units in the second operation mode. Thereby, the display device with a touch detection function 1 can suppress deterioration in image quality.

  In addition, when a plurality of touch detection periods are provided between the plurality of image display periods for the first to tenth units, the sound generated due to the change in the current or voltage of each part is large, and the first to the tenth When a plurality of image display periods for the unit are provided in succession, sound generation is small. In the second operation mode, the display device with a touch detection function 1 can continuously provide a plurality of image display periods for the first to tenth units. Therefore, the display device with a touch detection function 1 can suppress sounding in the second operation mode.

  Further, the display device with a touch detection function 1 can suppress power consumption in the second operation mode. FIG. 24 is a diagram illustrating a configuration of a source driver, a source selector, and a liquid crystal display device.

  The source driver 13 is supplied with a potential higher than a reference potential Vss (for example, the ground potential GND) from the first power supply 61 and supplied with a potential lower than the reference potential Vss from the second power supply 62.

  The source driver 13 includes switches SW1 and SW2 that select one of the output potential of the first power supply 61, the output potential of the second power supply 62, and the reference potential Vss and output the selected potential to the source selector 13S. The source driver 13 includes an image signal output unit 64 that outputs the time-division multiplexed image signal Vsig received from the display panel control unit 11F to the source selector 13S. The source driver 13 includes a switch control unit 63 that controls the switches SW1 and SW2 based on the mode signal Mode. The potential selected by the switch SW1 is output to the source selector 13S as the switch control signal VselA. The potential selected by the switch SW2 is output to the source selector 13S as the switch control signal VselB.

  The liquid crystal display device 20 includes a first pixel row 70 and a second pixel row 80. The first pixel row 70 includes, in the horizontal direction (X direction), an R (red) subpixel 71, a G (green) subpixel 72, a B (blue) subpixel 73, and R ( Red) sub-pixel 74. The second pixel row 80 includes, in the horizontal direction (X direction), an R (red) subpixel 81, a G (green) subpixel 82, a B (blue) subpixel 83, and an R ( Red) sub-pixel 84.

  The R (red) subpixel 71 and the R (red) subpixel 81 are connected to the pixel signal line SGL-1. The G (green) sub-pixel 72 and the G (green) sub-pixel 82 are connected to the pixel signal line SGL-2. The B (blue) subpixel 73 and the B (blue) subpixel 83 are connected to the pixel signal line SGL-3. The R (red) sub-pixel 74 and the R (red) sub-pixel 84 are connected to the pixel signal line SGL-4.

  The source selector 13S includes a wiring 91 to which the switch control signal VselA is applied, a wiring 92 to which the switch control signal VselB is applied, a first group of switches 93, and a second group of switches 94. The first group of switches 93 are controlled to open and close by a switch control signal VselA supplied from the source driver 13. The second group of switches 94 is controlled to open and close by a switch control signal VselB supplied from the source driver 13.

  The image signal Vsig-1 is supplied from the source driver 13 to one end of the switch 93A in the switch 93 of the first group. The other end of the switch 93A is connected to the subpixels 71 and 81 via the pixel signal line SGL-1. The image signal Vsig-1 is supplied from the source driver 13 to one end of the switch 94A in the second group of switches 94. The other end of the switch 94A is connected to the sub-pixels 73 and 83 via the pixel signal line SGL-3. The image signal Vsig-2 is supplied from the source driver 13 to one end of the switch 93B in the first group of switches 93. The other end of the switch 93B is connected to the sub-pixels 72 and 82 via the pixel signal line SGL-2. The image signal Vsig-2 is supplied from the source driver 13 to one end of the switch 94B in the second group of switches 94. The other end of the switch 94B is connected to the subpixels 74 and 84 via the pixel signal line SGL-4.

  With this configuration, the source selector 13S can sequentially switch the first group of switches 93 and the second group of switches 94 in the time division manner according to the switch control signals VselA and VselB. . Thus, the source selector 13S separates the pixel signals Vpix-1, Vpix-2, Vpix-3, and Vpix-4 from the multiplexed image signals Vsig-1 and Vsig-2. The source selector 13S supplies pixel signals Vpix-1, Vpix-2, Vpix-3, and Vpix-4 to the subpixels 71 to 74 and 81 to 84, respectively.

  When the switch control signal VselA is at a high level, the pixel signal Vpix-1 is supplied to the pixel signal line SGL-1, and the pixel signal Vpix-2 is supplied to the pixel signal line SGL-2. When the switch control signal VselB is at a high level, the pixel signal Vpix-1 is supplied to the pixel signal line SGL-3 connected to the B (blue) subpixel 73 and the B (blue) subpixel 83, The pixel signal Vpix-2 is supplied to the pixel signal line SGL-4 connected to the R (red) sub-pixel 74 and the R (red) sub-pixel 84.

  FIG. 25 is a diagram illustrating the timing of writing a pixel signal to a sub-pixel. FIG. 25A shows the writing timing of the pixel signal to the sub-pixel in the first operation mode, and FIG. 25B shows the writing timing of the pixel signal to the sub-pixel in the second operation mode. Show. FIGS. 25A and 25B show the write timings for two horizontal lines.

Figure 25 Referring to (A), in 1 write period of the horizontal line from the timing _{t 40} to the timing _{t 43,} the image signal Vsig-1 and Vsig-2 is written in the sub-pixels in the first pixel row 70 In the writing period for one horizontal line from timing t ₄₃ to timing t ₄₄ , the image signals Vsig-1 and Vsig-2 are written to the sub-pixels in the second pixel row 80.

Figure 25 Referring to (B), in 1 write period of the horizontal line from the timing _{t 50} to the timing _{t 55,} the image signal Vsig-1 and Vsig-2 is written in the sub-pixels in the first pixel row 70 , 1 write period of the horizontal line from the timing _{t 55} to the timing _{t 56,} the image signal Vsig-1 and Vsig-2 is written to the sub-pixel of the second pixel rows 80.

As described above, the display device with a touch detection function 1 can extend the image display period of each of the first to tenth units in the second operation mode. Therefore, one horizontal line of the writing period from the timing _{t 50} to the timing _{t 55} is longer than 1 write period of the horizontal line from the timing _{t 40} to the timing _{t 43.}

As shown in FIG. 25 (A), the switch control unit 63, in a first mode of operation, the writing period for one horizontal line is short, the switch control signal VselA, to rise steeply at timing t _41, the timing it is necessary to reduce sharply Standing in t _42. Accordingly, in the first operation mode, the first power supply 61 and the second power supply 62 realize a large potential change in a short time, and thus power consumption increases. In a first mode of operation, the switch control unit 63, at a timing _{t 41,} and connects the switch SW1 to the first power supply 61, the wires 91 to the high level. The switch control unit 63, at a timing _{t 42,} and connects the switch SW1 to the second power supply 62, the wires 91 to the low level.

  As described above, in the first operation mode, the switch control unit 63 switches between the output potential of the first power supply 61 and the output potential of the second power supply 62 without using the reference potential Vss. It is necessary to make the rising edge and falling edge of the control signal VselA steep.

On the other hand, as shown in FIG. 25B, in the second operation mode, the switch control unit 63 has a long writing period for one horizontal line, so that the switch control signal VselA is gradually raised and gently raised. It is possible to lower. Accordingly, in the second operation mode, the first power supply 61 and the second power supply 62 realize a relatively small potential change as compared with the first operation mode, so that the power consumption is relatively low. it can. The switch control unit 63, at a timing _{t 51,} and connects the switch SW1 to the reference potential Vss, and to precharge the lines 91 to the reference potential Vss. The switch control unit 63, at a timing _{t 52,} and connects the switch SW1 to the first power supply 61, the wires 91 to the high level. The switch control unit 63, at a timing _{t 53,} and connects the switch SW1 to the reference potential Vss, and to precharge the lines 91 to the reference potential Vss. The switch control unit 63, at a timing _{t 54,} and connects the switch SW1 to the second power supply 62, the wires 91 to the low level.

  As described above, in the second operation mode, the switch control unit 63 can precharge the wiring 91 using the reference potential Vss, so that the rising edge and the falling edge of the switch control signal VselA can be moderated. Therefore, the bias currents of the first power supply 61 and the second power supply 62 are relatively small compared to the first operation mode, and the power consumption is relatively low compared to the first operation mode.

Incidentally, the high level period of the switch control signals VselA from the timing _{t 52} in the second operation mode to the timing _{t 53,} the high-level switch control signal VselA from the timing _{t 41} of the first mode of operation until the timing _{t 42} It may be the same as the period. Alternatively, the potential change can be suppressed, the high level period of the switch control signals VselA from the timing _{t 52} in the second operation mode to the timing _{t 53,} from the timing _{t 41} of the first mode of operation until the timing _{t 42} The switch control signal VselA may be shorter than the high level period. Period from the timing _{t 51} to the timing _{t 54} in the second operation mode may be longer than the period from the timing _{t 41} of the first mode of operation until the timing _{t 42.}

  As described above, the display device with a touch detection function 1 performs mutual capacitance type touch detection in the first operation mode, and performs self-capacitance type touch detection in the second operation mode. The power consumption in the second operation mode can be suppressed.

<Second Operation Timing of Second Operation Mode of Display Device with Touch Detection Function>
The second display device 1 with a touch detection function when the frame frequency of the second operation mode is higher than the frame frequency of the first operation mode (for example, 59.94 Hz) (for example, 119.88 Hz). The operation timing in the operation mode will be described.

  The application executed at the frame frequency (for example, 119.88 Hz) in the second operation mode is exemplified by a moving image reproduction application, but is not limited thereto.

  FIG. 26 is a diagram illustrating operation timings in the second operation mode of the display device with a touch detection function. FIG. 26 is a diagram illustrating the operation timing when the frame frequency in the second operation mode is higher than the frame frequency (for example, 59.94 Hz) in the first operation mode (for example, 119.88 Hz). .

One frame period T31 is one starts at a timing _{t 60} of the falling of a vertical synchronization signal Vsync, a ends at timing _{t 65} of the falling edge of the next vertical synchronization signal Vsync. There is a start porch period VBP at the beginning of the frame period T31, and an end porch period VFP at the end of the frame period T31.

The host HOST at the timing _{t 60,} asserts a vertical synchronization signal Vsync. The host HOST at the timing _{t 61} after the start porch period VBP elapsed from the timing _{t 60,} it starts outputting the image signals Vdisp of 30 horizontal line included in the first unit. The host HOST outputs the image signal Vdisp to the memory 11A for each horizontal line in synchronization with the horizontal synchronization signal Hsync, and the memory 11A receives and stores the image signal Vdisp supplied from the host HOST. The period T32 is a transfer period of image signals Vdisp for 30 horizontal lines included in the first unit, and the period T33 is a transfer period of image signals Vdisp for 30 horizontal lines included in the second unit.

The delay circuit 11C at the timing _{t 62} after the delay time Delay elapses from the timing _{t 60,} asserts the internal vertical synchronizing signal Int-Vsync.

  In the second operation mode, the internal horizontal synchronization signal generation unit 11B generates and outputs an internal horizontal synchronization signal Int-Hsync having the same frequency as the horizontal synchronization signal Hsync. Note that the frequency of the internal horizontal synchronization signal Int-Hsync is the same as the frequency of the horizontal synchronization signal Hsync, and is not limited thereto. The frequency of the internal horizontal synchronization signal Int-Hsync may be 0.75 times or 0.8 times the frequency of the horizontal synchronization signal Hsync. The frequency of the internal horizontal synchronization signal Int-Hsync is exemplified as not more than one time the frequency of the horizontal synchronization signal Hsync.

Reset signal output unit 11D at a timing _{t 62} to the internal vertical synchronizing signal Int-Vsync is asserted, asserts the reset signal Reset. The counter 11E is reset to 0 when the reset signal Reset is asserted. Thereafter, the counter 11E counts the horizontal synchronization signal Hsync.

The display panel controller 11F, once turned D1 count value of the counter 11E is a predetermined value, at a timing t _63, starts the 30 image display of a horizontal line included in the first unit. The display panel control unit 11F displays an image for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 62} to the timing _{t 63} is the internal initiation porch period Int-VBP.

The display panel controller 11F, once turned D2 count value of the counter 11E is a predetermined value, at a timing t _64, starts the 30 image display of a horizontal line included in the second unit. The display panel control unit 11F displays an image for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 63} to the timing _{t 64} is an image display period T34 of the first unit.

The display panel controller 11F, once turned D3 count value of the counter 11E is a predetermined value, at a timing t _65, starts the 30 image display of a horizontal line included in the third unit. The display panel control unit 11F displays an image for each horizontal line in synchronization with the internal horizontal synchronization signal Int-Hsync.

Period from the timing _{t 64} to the timing _{t 65} is an image display period T35 of the second unit.

At timing _{t 65,} the image display period T36 of the third unit starts at a timing _{t 66,} the image display period T37 of the first 10 units are completed.

Touch detection control unit 40, once turned D4 count value of the counter 11E is a predetermined value, at a timing t _66, performing a touch detection self capacitive. The touch detection control unit 40 supplies the touch drive signal Vcomts1 to the drive electrodes COML all at once to perform touch detection in the Y direction, and simultaneously supplies the touch drive signal Vcomts2 to the touch detection electrodes TDL to detect touch in the X direction. May be performed. Alternatively, the touch detection control unit 40 performs self-capacitance type touch detection in the X direction (or Y direction), and when the self-capacitance type touch detection in the X direction (or Y direction) ends, the Y direction. Self-capacitive touch detection in the (or X direction) may be performed.

A period from timing t ₆₆ to timing t ₆₇ when the touch detection ends is a touch detection period T38.

From the timing _{t 67,} the period from the timing _{t 68} to the internal vertical synchronizing signal Int-Vsync is asserted, the internal ends porch period Int-VFP.

  The length of the first unit image display period T34 (see FIG. 26) in the second operation mode and the length of the first unit image display period T5 (see FIG. 18) in the first operation mode. May be different. The length of the image display period T34 of the first unit in the second operation mode may be shorter than the length of the image display period T5 of the first unit in the first operation mode.

  The display device with a touch detection function 1 shifts to the second operation mode when executing a predetermined application (for example, a video playback application), and executes an application (for example, a game application) other than the predetermined application. Sometimes, the mode may transition to the first operation mode.

  When the present inventor executed a moving image playback application on a commercially available electronic device, it was confirmed that multi-touch is not supported during the execution of the moving image playback application. In other words, it has been confirmed that the consumer accepts that multi-touch is not supported while the video playback application is being executed.

  Alternatively, the display device with a touch detection function 1 shifts to the second operation mode when no touch is detected for a predetermined period in the first operation mode, and first when the touch is detected in the second operation mode. The operation mode may be changed to.

[effect]
The display device 1 with a touch detection function has the following effects. The display device with a touch detection function 1 performs mutual capacitance type touch detection in the first operation mode, and performs self-capacitance type touch detection in the second operation mode. The time required for the self-capacitance type touch detection is relatively short compared to the mutual capacitance type touch detection. Accordingly, the display device with a touch detection function 1 can extend the image display period of each of the first to tenth units in the second operation mode. Thereby, the display device with a touch detection function 1 can suppress deterioration in image quality.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to such embodiments. The content disclosed in the embodiment is merely an example, and various modifications can be made without departing from the spirit of the present invention. Appropriate changes made without departing from the spirit of the present invention naturally belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Display device with a touch detection function 2 Pixel substrate 3 Counter substrate 6 Liquid crystal layer 10 Display unit with a touch detection function 11 Display control unit 11A Memory 11B Internal horizontal synchronization signal generation unit 11C Delay circuit 11D Reset signal output unit 11E Counter 12 Gate driver 13 Source driver 13S Source selector 14 Drive electrode driver 19 COG
DESCRIPTION OF SYMBOLS 20 Liquid crystal display device 21 TFT substrate 22 Pixel electrode 30 Touch detection device 31 2nd insulating substrate 32 Color filter 40 Touch detection control part 40A Self switch 40B Selector 40C Touch driver 40D Controller CG Cover member COML Drive electrode CTRL Control part DSP Display part GCL Scan signal line HOST Host IS input surface Pix pixel SE touch detection unit SGL pixel signal line SPix sub pixel TDL touch detection electrode T flexible printed circuit board Tr TFT element

Claims (20)

A touch detection unit including a first group of electrodes extending along a first direction and a second group of electrodes extending along a second direction intersecting the first direction;
A display for displaying an image;
An image is displayed at a first frame frequency and a first operation mode for performing touch detection for detecting contact or proximity of an object to be detected, and an image at a second frame frequency different from the first frame frequency. And a second operation mode for performing touch detection;
With
The controller is
In the touch detection period of the first operation mode, a touch detection drive signal is sequentially supplied to the first group of electrodes, and the mutual capacitance between the first group of electrodes and the second group of electrodes is increased. Based on the self-capacitance of the first group of electrodes by supplying a touch detection drive signal all at once to the first group of electrodes during the touch detection period of the second operation mode. A display device with a touch detection function that performs touch detection, supplies a touch detection drive signal to the second group of electrodes all at once, and performs touch detection based on the self-capacitance of the second group of electrodes. The display device with a touch detection function according to claim 1, wherein the first group of electrodes is shared by the touch detection unit and the display unit. Each of the touch detection unit and the display unit includes a plurality of units each including a plurality of lines.
In the first operation mode, a plurality of touch detection periods for the plurality of units are provided between a plurality of image display periods for the plurality of units,
The display device with a touch detection function according to claim 2, wherein in the second operation mode, a plurality of image display periods for the plurality of units are continuously provided. The display device with a touch detection function according to claim 1, wherein a length of the image display period in the first operation mode is different from a length of the image display period in the second operation mode. The display device with a touch detection function according to claim 1, wherein the second frame frequency is lower than the first frame frequency. The display device with a touch detection function according to claim 1, wherein the second frame frequency is higher than the first frame frequency. The controller is
Including a display control unit for displaying an image;
The display control unit
A source driver that outputs an image signal in which a pixel signal supplied to a pixel in the display unit is time-division multiplexed and a control signal for separating the pixel signal multiplexed in the image signal;
A source selector that separates the pixel signal multiplexed into the image signal based on the control signal and outputs the separated pixel signal;
Including
The source driver is
In the second operation mode, when the control signal is changed from a low level to a high level, the control signal is changed from a low level to an intermediate level between a low level and a high level, and then the control signal is changed. When the signal is changed from the intermediate level to the high level and the control signal is changed from the high level to the low level, the control signal is changed from the high level to the intermediate level, and then the control signal is changed from the intermediate level to the low level. The display device with a touch detection function according to any one of claims 1 to 6. The controller is
Including a touch detection control unit for detecting contact or proximity of an object to be detected;
The touch detection control unit includes:
When performing touch detection based on the mutual capacitance between the first group of electrodes and the second group of electrodes, sequentially output touch detection signals directed to the first group of electrodes, When touch detection is performed based on the self-capacitance of the first group of electrodes, touch detection signals directed to the first group of electrodes are output all at once, and the self-capacitance of the second group of electrodes is output. A touch driver that outputs touch detection signals for the second group of electrodes all at once,
When performing touch detection based on the self-capacitance of the first group of electrodes, a self-block that conducts the touch driver and the first group of electrodes;
When performing touch detection based on the mutual capacitance between the first group of electrodes and the second group of electrodes, one electrode of the first group of electrodes and the touch driver are used. The display device with a touch detection function according to claim 1, comprising: a selector that conducts. The controller is
In the touch detection period of the second operation mode, a touch detection drive signal is supplied to the first group of electrodes and the second group of electrodes all at once, and the self-capacitance of the first group of electrodes and the first group of electrodes are supplied. The display device with a touch detection function according to any one of claims 1 to 8, wherein touch detection is performed based on self-capacitance of two groups of electrodes. The controller is
In the touch detection period of the second operation mode, a touch detection drive signal is simultaneously supplied to a group of the first group of electrodes and the second group of electrodes, and the first group of electrodes and the second group Touch detection is performed based on the self-capacitance of one group of the electrodes of the group, and then the touch detection driving signal is supplied to the other group of the first group of electrodes and the second group of electrodes all at once. The touch detection function according to claim 1, wherein touch detection is performed based on a self-capacitance of another group of the first group of electrodes and the second group of electrodes. Display device. A touch detection unit including a first group of electrodes extending along a first direction and a second group of electrodes extending along a second direction intersecting the first direction; A method for controlling a display device with a touch detection function comprising a display unit for displaying,
In the touch detection period of the first operation mode in which an image is displayed at the first frame frequency and touch detection for detecting contact or proximity of an object to be detected is performed, touch detection drive signals are sequentially supplied to the first group of electrodes. And performing touch detection based on the mutual capacitance between the first group of electrodes and the second group of electrodes,
In the touch detection period of the second operation mode in which an image is displayed at a second frame frequency different from the first frame frequency and touch detection is performed, touch detection drive signals are supplied to the first group of electrodes all at once. Then, touch detection is performed based on the self-capacitance of the first group of electrodes, and a touch detection drive signal is simultaneously supplied to the second group of electrodes, so that the self-capacitance of the second group of electrodes is obtained. Control method that performs touch detection based on. The control method according to claim 11, wherein the first group of electrodes is shared by the touch detection unit and the display unit. Each of the touch detection unit and the display unit includes a plurality of units each including a plurality of lines.
In the first operation mode, a plurality of touch detection periods for the plurality of units are arranged between a plurality of image display periods for the plurality of units,
The control method according to claim 12, wherein in the second operation mode, a plurality of image display periods for the plurality of units are continuously arranged. 14. The control method according to claim 11, wherein a length of the image display period in the first operation mode is different from a length of the image display period in the second operation mode. The control method according to any one of claims 11 to 14, wherein the second frame frequency is lower than the first frame frequency. The control method according to any one of claims 11 to 14, wherein the second frame frequency is higher than the first frame frequency. In the second operation mode, when the control signal for separating the image signal obtained by time-division multiplexing the pixel signal supplied to the pixel in the display unit is changed from the first level to the second level. Changing the control signal from the first level to a third level between the first level and the second level, and then changing the control signal from the third level to the second level. When the control signal is changed from the second level to the first level, the control signal is changed from the second level to the third level, and then the control signal is changed. The control method according to any one of claims 11 to 16, wherein a signal is changed from the third level to the first level. When performing touch detection based on the self-capacitance of the first group of electrodes, a touch driver that simultaneously outputs touch detection signals directed to the first group of electrodes and the first group of electrodes Conducting,
When performing touch detection based on the mutual capacitance between the first group of electrodes and the second group of electrodes, one electrode of the first group of electrodes and the touch driver are used. The control method according to any one of claims 11 to 17. In the touch detection period of the second operation mode, a touch detection drive signal is supplied to the first group of electrodes and the second group of electrodes all at once, and the self-capacitance of the first group of electrodes and the first group of electrodes are supplied. The control method according to any one of claims 11 to 18, wherein touch detection is performed based on self-capacitance of two groups of electrodes. In the touch detection period of the second operation mode, a touch detection drive signal is simultaneously supplied to a group of the first group of electrodes and the second group of electrodes, and the first group of electrodes and the second group Touch detection is performed based on the self-capacitance of one group of the electrodes of the group, and then the touch detection driving signal is supplied to the other group of the first group of electrodes and the second group of electrodes all at once. The control method according to claim 11, wherein touch detection is performed based on a self-capacitance of another group of the first group of electrodes and the second group of electrodes.

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