JP7117671B2 - Display system and control method - Google Patents

Description

The present invention relates to a display system and control method having a touch detection function.

In recent years, a display input device equipped with a touch display that displays a GUI on a display screen and performs instruction input by directly touching the display screen with a user's finger or the like has become widespread (see, for example, Patent Documents 1 and 2). . This type of display/input device is widely used in mobile terminals and terminals with limited installation space because the configuration can be simplified compared to a display/input device that has a separate input unit such as a button or keyboard for the display device. ing.

JP 2014-132445 A JP 2016-200886 A

Further improvements are needed in display systems with touch displays.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object thereof is to provide a technique capable of realizing further improvement in a display system.

In order to solve the above problems, a display system according to one aspect of the present invention includes a first display device having a plurality of first sensor electrodes, and a plurality of second sensor electrodes arranged adjacent to the first display device. a first drive circuit for supplying a first touch drive signal varying between a first voltage and a second voltage to the plurality of first sensor electrodes; and a third voltage and a fourth voltage. a second drive circuit for supplying the plurality of second sensor electrodes with a second touch drive signal that varies between voltages and has a phase difference with respect to the first touch drive signal; acquiring a plurality of first detection values based on the capacitance of each of the plurality of first sensor electrodes at a first acquisition timing after a predetermined first time has elapsed from the first timing of the voltage change; A first touch detection circuit that detects a touch of an object to the first display device based on the first detection value of and a second timing that the second touch drive signal changes from the third voltage to the fourth voltage. acquiring a plurality of second detection values based on the capacitance of each of the plurality of second sensor electrodes at a second acquisition timing after the second time has elapsed, and performing a second display based on the plurality of acquired second detection values; a second touch detection circuit for detecting a touch of an object to the device. During the first period from the first timing to the first acquisition timing, and from the third timing when the first touch drive signal changes from the second voltage to the first voltage, the voltages of the plurality of first sensor electrodes are substantially the first voltage. The second period until the voltage becomes the timing is non-overlapping with the third period from the second timing to the second acquisition timing.

Another aspect of the invention is a control method. The method comprises: a first display device having a plurality of first sensor electrodes; a second display device disposed adjacent to the first display device and having a plurality of second sensor electrodes; a first voltage and a second voltage; a first drive circuit that supplies a first touch drive signal that varies between a plurality of first sensor electrodes to the plurality of first sensor electrodes; a second drive circuit for supplying a second touch drive signal having a phase difference to the plurality of second sensor electrodes; Acquiring a plurality of first detection values based on the capacitance of each of the plurality of first sensor electrodes at a first acquisition timing after a lapse of time, and based on the acquired plurality of first detection values, to the first display device a first touch detection circuit that detects a touch of an object; A second touch detection circuit that acquires a plurality of second detection values based on respective capacitances of the second sensor electrodes and detects a touch of an object to the second display device based on the acquired plurality of second detection values. and a first period from a first timing to a first acquisition timing, and a plurality of a first driving circuit, such that a second period until the timing at which the voltage of the first sensor electrode of is substantially the first voltage does not overlap with a third period from the second timing to the second acquisition timing; Controlling the second drive circuit, the first touch detection circuit and the second touch detection circuit.

The above aspects enable further improvements in display systems.

1 is a block diagram of a display system according to a first embodiment; FIG. 2 is a diagram schematically showing the circuit configuration of the display device of FIG. 1; FIG. 3 is a top view showing the arrangement of common electrodes in FIG. 2; FIG. FIG. 4 is a diagram showing timings of a first frame period in a first display device and a second frame period in a second display device; FIG. 5(a) is a diagram for explaining the operation of the display device during the first touch detection period T1a in FIG. 4, and FIG. 5(b) is a diagram for explaining the operation of the display device during the first touch detection period T2a. is. FIG. 6A is a diagram for explaining the operation of the display device during the first touch detection period T3a, and FIG. 6B is a diagram for explaining the operation of the display device during the first touch detection period T4a. FIG. 7A is a diagram showing the waveforms of the first touch drive signal and the voltage of the common electrode of the first display device in each touch detection period, and FIG. FIG. 4 is a diagram showing waveforms of a driving signal and a voltage of a common electrode of a second display device; FIG. 8(a) is a diagram showing another example of waveforms of the first touch drive signal and the voltage of the common electrode of the first display device in each touch detection period, and FIG. 8(b) shows each touch detection period. FIG. 12 is a diagram showing another example of the waveforms of the second touch drive signal and the voltage of the common electrode of the second display device in FIG. FIG. 9A is a diagram for explaining the operation of the display device in the first touch detection period T4a of the display system of the comparative example, and FIG. FIG. 9C is a diagram showing waveforms of signals, and FIG. 9C is a diagram showing waveforms of the second touch drive signal in each touch detection period of the comparative example. 2 is a flowchart showing activation processing of the display system of FIG. 1; FIG. 11(a) is a diagram showing the waveforms of the first touch drive signal and the voltage of the common electrode of the first display device in each touch detection period according to the second embodiment, and FIG. FIG. 10 is a diagram showing waveforms of a second touch drive signal and a voltage of a common electrode of the second display device in each touch detection period according to the second embodiment; FIG. 12(a) is a diagram showing the waveform of the first touch drive signal according to the third embodiment, and FIG. 12(b) is the waveform of the second touch drive signal according to the third embodiment. It is a figure which shows. FIG. 12 is a block diagram of a display system according to a fourth embodiment; FIG. FIG. 14 is a flowchart showing activation processing of the display system of FIG. 13; FIG.

(Findings on which this disclosure is based)
Prior to specifically describing the embodiments, the underlying knowledge will be described. In touch displays, it is desired to reduce the influence of noise from the viewpoint of operational stability. As a technique for reducing the influence of external noise derived from the operation of an external device or the like in a touch display, for example, the techniques described in Patent Documents 1 and 2 are known.

By the way, there is a case where two touch displays are arranged side by side. In this arrangement, the inventors have found a problem that the noise derived from the touch drive signals of the touch displays interferes with each other and affects the touch detection. In order to solve this problem, the display system according to the present disclosure is configured as follows.

Hereinafter, the same or equivalent constituent elements, members, and steps shown in each drawing are denoted by the same reference numerals, and redundant description will be omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding.

(First embodiment)
FIG. 1 is a block diagram of a display system 1 according to the first embodiment. Although the display system 1 is an in-vehicle display system 1 installed in a vehicle such as an automobile, the application is not particularly limited, and the display system 1 may be used in a portable device or the like.

The display system 1 comprises a host 10, a first display module 20a and a second display module 20b. Hereinafter, the first display module 20a and the second display module 20b are referred to as the display module 20 when not distinguished from each other. The display module 20 is also called a display panel.

The host 10 performs various functions such as radio, car navigation, Bluetooth (registered trademark) communication, and controls two display modules 20 . The host 10 has a controller 12 .

The control device 12 is, for example, a CPU and is also called a host CPU. The control device 12 supplies image data DD and control data CD to the two display modules 20, and controls the two display modules 20 based on these data.

The first display module 20a includes a first display device 22a and a first display control device 24a. The second display module 20b includes a second display device 22b and a second display control device 24b. Hereinafter, when the first display device 22a and the second display device 22b are not distinguished, they are called the display device 22, and when the first display control device 24a and the second display control device 24b are not distinguished, they are called the display control device 24. .

The two display devices 22 are used, for example, as a center display in a vehicle on which a car navigation screen or the like is displayed, and are arranged horizontally or vertically adjacent to each other. The two display devices 22 may each display a part of one screen, such as a car navigation screen, to constitute one screen with two screens, or one may display a first screen such as a car navigation screen. and a second screen, such as a television screen, that is different from the first screen.

The display device 22 is an in-cell type IPS (In Plane Switching) type liquid crystal display device, is configured as a touch display, and is capable of detecting a touch position. The configuration of the display device 22 is, for example, a well-known configuration described below.

FIG. 2 schematically shows the circuit configuration of the display device 22 of FIG. FIG. 2 also shows the schematic layout of each component. The display device 22 includes a plurality of gate lines G1, G2, . . . extending in the row direction, a plurality of source lines S1, S2, . It comprises an electrode 32 and a plurality of common electrodes 34 . Each pixel switching element 30 is a thin film transistor, and is provided near the intersection of the gate line and the source line to correspond to the pixel. In each pixel switching element 30, a gate line is connected to the gate, a source line is connected to the source, and a pixel electrode 32 is connected to the drain. A plurality of pixel switching elements 30 and a plurality of pixel electrodes 32 are arranged for one common electrode 34 . The electric field between the pixel electrode 32 and the common electrode 34 controls the liquid crystal layer. The common electrode 34 is shared for image display and touch detection. Therefore, the display device 22 can be made thin by reducing the number of electrode layers. The common electrode 34 of the first display device 22a can also be called a first sensor electrode. The common electrode 34 of the second display device 22b can also be called a second sensor electrode.

FIG. 3 is a top view showing the arrangement of the common electrode 34 of FIG. A plurality of common electrodes 34 are arranged in a matrix. Each common electrode 34 of the first display device 22a is connected by a signal line 36 to the first display controller 24a, and each common electrode 34 of the second display device 22b is connected by a signal line 36 to the second display controller 24b. be done.

The display device 22 detects a touch position by a self-capacitance method. When a finger approaches the display surface of the display device 22, a capacitance is generated between the common electrode 34 and the finger. When the capacitance is generated, the parasitic capacitance in the common electrode 34 increases, and the current when supplying the touch drive signal to the common electrode 34 increases. A touch position is detected based on the amount of change in this current.

Return to FIG. The first display control device 24a is configured as an IC, for example, and controls the first display device 22a according to control data CD and image data DD from the host 10. FIG. The first display control device 24a includes a first control circuit 70a, a third drive circuit 72a, a first drive circuit 74a, a first touch detection circuit 76a, and a first clock generation circuit 78a.

The first control circuit 70a is composed of, for example, a microcomputer, and controls signal generation of the first clock generation circuit 78a, the third drive circuit 72a, and the first drive circuit 74a, the operation timing of the first touch detection circuit 76a, and the like.

The first control circuit 70a controls the third drive circuit 72a, It controls the first drive circuit 74a and the first touch detection circuit 76a. The first frame period can also be called a first vertical synchronization period. Details of the first frame period will be described later.

The first clock generation circuit 78a generates the first reference clock signal CK1 under the control of the first control circuit 70a. The third drive circuit 72a generates the source signal SS based on the image data DD from the host 10 and the generated first reference clock signal CK1 under the control of the first control circuit 70a. The third drive circuit 72a generates the gate signal GS based on the generated first reference clock signal CK1 under the control of the first control circuit 70a.

The third drive circuit 72a sequentially supplies the source signal SS to the plurality of source lines of the first display device 22a and sequentially supplies the gate signal GS to the plurality of gate lines of the first display device 22a.

Under the control of the first control circuit 70a, the first drive circuit 74a generates a reference voltage VCOM which is a predetermined fixed voltage, and based on the generated first reference clock signal CK1, the first drive circuit 74a is a rectangular wave. A one-touch drive signal TX1 is generated. The first drive circuit 74a supplies the reference voltage VCOM or the first touch drive signal TX1 to the entire plurality of common electrodes 34 of the first display device 22a via the signal line 36 of FIG.

The first touch detection circuit 76a detects a touch of an object to the first display device 22a. Under the control of the first control circuit 70a, the first touch detection circuit 76a receives the touch detection signal RX from the common electrode 34 when the first touch drive signal TX1 is supplied to the common electrode 34, and outputs the touch detection signal RX. Based on this, the touch position is detected. The first touch detection circuit 76a outputs information on the detected touch position to the first control circuit 70a.

The first control circuit 70 a derives the coordinate data TD of the touch position based on the touch position information from the first touch detection circuit 76 a and outputs the coordinate data TD to the control device 12 of the host 10 . The control device 12 executes various processes according to the coordinate data TD.

The first clock generation circuit 78a generates a synchronization signal SY synchronized with the first reference clock signal CK1, and outputs the synchronization signal SY to the second display control device 24b, for example, at each start timing of the first frame period. The output timing of the synchronization signal SY is not particularly limited as long as the signals can be synchronized between the first display control device 24a and the second display control device 24b.

The second display control device 24b is configured, for example, as an IC, and controls the second display device 22b according to control data CD and image data DD from the host 10 and a synchronization signal SY from the first display control device 24a. The basic operation of the second display control device 24b is common to the operation of the first display control device 24a. The second display control device 24b includes a second control circuit 70b, a fourth drive circuit 72b, a second drive circuit 74b, a second touch detection circuit 76b, and a second clock generation circuit 78b.

The second control circuit 70b is composed of, for example, a microcomputer, and generates signals for the second clock generation circuit 78b, the fourth drive circuit 72b, and the second drive circuit 74b, and operates the second touch detection circuit 76b based on the synchronization signal SY. Control timing etc. The second control circuit 70b and the above-described first control circuit 70a can be collectively called a control circuit.

The second control circuit 70b controls the fourth drive circuit 72b so that one frame of the display image is drawn on the second display device 22b and the touch detection of one screen is performed at least once during the second frame period. It controls the second drive circuit 74b and the second touch detection circuit 76b. The second control circuit 70b controls the start timing of the second frame period to match the start timing of the first frame period based on the synchronization signal SY. The second frame period can also be called a second vertical synchronization period. Details of the second frame period will be described later.

The second clock generation circuit 78b generates a second reference clock signal CK2 synchronized with the first reference clock signal CK1 and having the same frequency as the first reference clock signal CK1 under the control of the second control circuit 70b. That is, the phase difference of the second reference clock signal CK2 with respect to the first reference clock signal CK1 is set to substantially zero. The fourth drive circuit 72b generates the source signal SS based on the image data DD from the host 10 and the generated second reference clock signal CK2 under the control of the second control circuit 70b. The fourth drive circuit 72b generates the gate signal GS based on the generated second reference clock signal CK2 under the control of the second control circuit 70b.

The fourth drive circuit 72b sequentially supplies the source signal SS to the plurality of source lines of the second display device 22b and sequentially supplies the gate signal GS to the plurality of gate lines of the second display device 22b.

The second drive circuit 74b generates the reference voltage VCOM under the control of the second control circuit 70b, and generates the rectangular wave second touch drive signal TX2 based on the generated second reference clock signal CK2. . The second drive circuit 74b supplies the reference voltage VCOM or the second touch drive signal TX2 to the entire plurality of common electrodes 34 of the second display device 22b via the signal line 36 of FIG.

The second touch detection circuit 76b detects a touch of an object to the second display device 22b. Under the control of the second control circuit 70b, the second touch detection circuit 76b receives the touch detection signal RX from the common electrode 34 when the second touch drive signal TX2 is supplied to the common electrode 34, and outputs the touch detection signal RX. Based on this, the touch position is detected. The second touch detection circuit 76b outputs information on the detected touch position to the second control circuit 70b.

The second control circuit 70 b derives the coordinate data TD of the touch position based on the information of the touch position from the second touch detection circuit 76 b and outputs the coordinate data TD to the control device 12 .

The configuration of the control device 12, the first control circuit 70a, and the second control circuit 70b can be realized by cooperation of hardware resources and software resources, or only by hardware resources. Analog devices, microcomputers, DSPs, ROMs, RAMs, FPGAs, and other LSIs can be used as hardware resources. Programs such as firmware can be used as software resources.

FIG. 4 shows the timing of the first frame period Fa in the first display device 22a and the second frame period Fb in the second display device 22b.

The first frame period Fa includes four first display periods Da and four first touch detection periods T1a, T2a, T3a, T4a. The first display periods Da and the first touch detection periods are alternately arranged. In the first frame period Fa, a first display period Da, a first touch detection period T1a, a first display period Da, a first touch detection period T2a, a first display period Da, a first touch detection period T3a, and a first display period Da and the first touch detection period T4a are arranged in this order.

The second frame period Fb includes four second display periods Db and four second touch detection periods T1b, T2b, T3b, T4b. The second display period Db and the second touch detection period are alternately arranged. In the second frame period Fb, a second display period Db, a second touch detection period T1b, a second display period Db, a second touch detection period T2b, a second display period Db, a second touch detection period T3b, a second display period Db and the second touch detection period T4b are arranged in this order.

The length of the first display period Da is equal to the length of the second display period Db. The first touch detection periods T1a to T4a and the second touch detection periods T1b to T4b have the same length. The length of the first frame period Fa is equal to the length of the second frame period Fb. The start timing (time t0) of the first frame period Fa coincides with the start timing of the second frame period Fb.

The number of first display periods Da and the number of first touch detection periods in the first frame period Fa, and the number of second display periods Db and the number of second touch detection periods in the second frame period Fb are set to "4". Not limited.

The first display device 22a displays 1/4 of one frame every first display period Da. One frame is displayed by the four first display periods Da of the first frame period Fa. Specifically, during the first display period Da, the third drive circuit 72a supplies the source signal SS to the plurality of source lines, supplies the gate signal GS to the target gate line, and the first drive circuit 74a supplies the plurality of source lines with the gate signal GS. A reference voltage VCOM is supplied to the common electrode 34 of the . The first drive circuit 74a stops supplying the first touch drive signal TX1 during the first display period Da.

The second display device 22b displays 1/4 of one frame every second display period Db. One frame is displayed by the four second display periods Db of the second frame period Fb. Specifically, during the second display period Db, the fourth drive circuit 72b supplies the source signal SS to the plurality of source lines, supplies the gate signal GS to the target gate line, and the second drive circuit 74b supplies the plurality of source lines with the gate signal GS. A reference voltage VCOM is supplied to the common electrode 34 of the . The second drive circuit 74b stops supplying the second touch drive signal TX2 during the second display period Db.

FIG. 5(a) is a diagram for explaining the operation of the display device 22 during the first touch detection period T1a of FIG. The first display device 22a and the second display device 22b are arranged horizontally adjacent to each other as viewed from the observer.

The first display device 22a includes first touch detection regions R4a, R3a, R2a, and R1a arranged in order in a direction approaching the second display device 22b. That is, the first touch detection areas R1a, R2a, R3a, and R4a are arranged in the horizontal direction, which is the direction along which the first display device 22a and the second display device 22b are arranged. The rightmost first touch detection region R1a is adjacent to the second display device 22b. A plurality of common electrodes 34 in the entire first display device 22a are arranged in each of the first touch detection regions R1a to R4a.

The second display device 22b includes second touch detection regions R1b, R2b, R3b, and R4b arranged in order in the direction away from the first display device 22a. That is, the second touch detection areas R1b, R2b, R3b, and R4b are arranged in the horizontal direction. The leftmost second touch detection region R1b is adjacent to the first display device 22a. A plurality of common electrodes 34 of the entire second display device 22b are arranged in each of the second touch detection regions R1b to R4b. The number of touch detection areas of one display device 22 is not limited to "4".

The first drive circuit 74a supplies the first touch drive signal TX1 to the plurality of common electrodes 34 of the entire first display device 22a during the first touch detection period T1a. During the first touch detection period T1a, the first touch detection circuit 76a receives the touch detection signals RX from the plurality of common electrodes 34 of the first touch detection region R4a to be detected, to the first touch detection region R4a. object touch.

The second drive circuit 74b supplies the second touch drive signal TX2 to the entire plurality of common electrodes 34 of the second display device 22b during the second touch detection period T1b. During the second touch detection period T1b, the second touch detection circuit 76b receives touch detection signals RX from the plurality of common electrodes 34 of the second touch detection region R1b to be detected, to the second touch detection region R1b. object touch.

FIG. 5B is a diagram for explaining the operation of the display device 22 during the first touch detection period T2a. Since the operations of the first drive circuit 74a and the second drive circuit 74b in each touch detection period are common, description thereof will be omitted. During the first touch detection period T2a, the first touch detection circuit 76a detects touch detection signals in the first touch detection region R3a based on the touch detection signals RX received from the plurality of common electrodes 34 of the first touch detection region R3a to be detected. Detect touch.

During the second touch detection period T2b, the second touch detection circuit 76b detects touch detection signals in the second touch detection region R2b based on the touch detection signals RX received from the plurality of common electrodes 34 of the second touch detection region R2b to be detected. Detect touch.

FIG. 6A is a diagram for explaining the operation of the display device 22 during the first touch detection period T3a. During the first touch detection period T3a, the first touch detection circuit 76a detects touch detection signals in the first touch detection region R2a based on the touch detection signals RX received from the plurality of common electrodes 34 of the first touch detection region R2a to be detected. Detect touch.

During the second touch detection period T3b, the second touch detection circuit 76b detects touch detection signals in the second touch detection region R3b based on the touch detection signals RX received from the plurality of common electrodes 34 of the second touch detection region R3b to be detected. Detect touch.

FIG. 6B is a diagram for explaining the operation of the display device 22 during the first touch detection period T4a. During the first touch detection period T4a, the first touch detection circuit 76a detects touch detection signals in the first touch detection region R1a based on the touch detection signals RX received from the plurality of common electrodes 34 of the first touch detection region R1a to be detected. Detect touch.

During the second touch detection period T4b, the second touch detection circuit 76b detects touch detection signals in the second touch detection region R4b based on the touch detection signals RX received from the plurality of common electrodes 34 of the second touch detection region R4b to be detected. Detect touch.

In this manner, the first touch detection circuit 76a detects a touch in a different first touch detection area for each first touch detection period. One touch detection for one screen is performed by four first touch detection periods in the first frame period Fa.

The second touch detection circuit 76b detects a touch in a different second touch detection area for each second touch detection period. The four second touch detection periods of the second frame period Fb perform one touch detection for one screen.

FIG. 7A shows waveforms of the first touch drive signal TX1 and the voltage Vc1 of the common electrode 34 of the first display device 22a in each touch detection period. FIG. 7B shows waveforms of the second touch drive signal TX2 and the voltage Vc2 of the common electrode 34 of the second display device 22b in each touch detection period.

Depending on the position of the common electrode 34 within the display device 22, ie, depending on the length of the signal line 36, the voltages Vc1 and Vc2 may have different waveforms for each common electrode 34. FIG. This is because the larger the resistance value of the signal line 36, the longer the charge time and the discharge time. The waveforms of the voltages Vc1 and Vc2 shown are for the common electrode 34 with the longest charging and discharging times, respectively.

The first touch drive signal TX1 varies between the first voltage V1 and the second voltage V2. Here, the first voltage V1 is at a low level and the second voltage V2 is at a high level higher than the first voltage V1, but the reverse is also possible.

A timing at which the first touch drive signal TX1 changes from the first voltage V1 to the second voltage V2 is defined as a first timing A1, and a timing at which the second voltage V2 changes to the first voltage V1 is defined as a third timing A3.

Charging of the common electrode 34 is started at the first timing A1, the voltage Vc1 increases from the first voltage V1, and substantially reaches the second voltage V2 at the fifth timing A5. The fifth timing A5 is the timing when the voltage Vc1 of the plurality of common electrodes 34 of the entire first display device 22a substantially becomes the second voltage V2. It is assumed that the voltage Vc1 substantially becomes the second voltage V2 when the voltages Vc1 of all the common electrodes 34 become equal to or greater than a first percentage of the second voltage V2. The first percentage is, for example, 95%, 98%, etc., and can be appropriately set through experiments or simulations.

Thereafter, discharge of the common electrode 34 is started at a third timing A3, the voltage Vc1 drops from the second voltage V2, and substantially reaches the first voltage V1 at a seventh timing A7. The seventh timing A7 is the timing when the voltage Vc of the plurality of common electrodes 34 of the entire first display device 22a substantially becomes the first voltage V1. It is assumed that the voltage Vc1 is substantially the first voltage V1 when the voltages Vc1 on all common electrodes 34 are less than or equal to a predetermined second percentage of the first voltage V1. The second percentage is, for example, 105%, 102%, etc., and can be appropriately set through experiments or simulations.

The first touch detection circuit 76a detects a first acquisition timing D1 when a predetermined first time t1 has passed since the first timing A1, and a third acquisition timing D3 when the first time t1 has passed since the third timing A3. , a plurality of first detection values based on respective capacitances of the plurality of common electrodes 34 are obtained. The first touch detection circuit 76a receives touch detection signals from each common electrode 34 between the first timing A1 and the first acquisition timing D1 and between the third timing A3 and the third acquisition timing D3. A first detection value is derived based on RX. A well-known technique can be used to derive the first detection value. Each first detection value represents the difference value between the capacitance of the corresponding common electrode 34 and the reference capacitance. The greater the amount of change in the capacitance of the common electrode 34 due to the touch of the object, the greater the first detection value. If there is no touch and the amount of change in capacitance of the common electrode 34 is zero, the first detection value is zero. The first touch detection circuit 76a detects a touch based on the acquired plurality of first detection values. The timing of detecting a touch is not particularly limited, and may be every first acquisition timing D1, every third acquisition timing D3, or every several acquisition timings. The first touch detection circuit 76a compares the first detection value of each common electrode 34 with a predetermined touch detection threshold, and determines that there is a touch at the position of the common electrode 34 when the first detection value is equal to or greater than the touch detection threshold. judge. The first time t1 can be appropriately set through experiments or simulations so that the first acquisition timing D1 comes after the fifth timing A5 and the third acquisition timing D3 comes after the seventh timing A7.

The second touch drive signal TX2 varies between the third voltage V3 and the fourth voltage V4. Here, the third voltage V3 is at low level and the fourth voltage V4 is at high level higher than the third voltage V3, but the reverse is also possible. The first voltage V1 and the third voltage V3 are substantially equal, but may be different. The second voltage V2 and the fourth voltage V4 are substantially equal, but may be different.

The timing at which the second touch drive signal TX2 changes from the third voltage V3 to the fourth voltage V4 is defined as a second timing A2, and the timing at which the fourth voltage V4 changes to the third voltage V3 is defined as a fourth timing A4.

The frequencies of the first touch drive signal TX1 and the second touch drive signal TX2 are substantially the same, and the duty ratios are also substantially the same. The second touch drive signal TX2 has a predetermined phase difference with respect to the first touch drive signal TX1. In this example, the second timing A2 is later than the first timing A1, and the fourth timing A4 is later than the third timing A3.

Charging of the common electrode 34 is started at the second timing A2, the voltage Vc2 increases from the third voltage V3, and substantially reaches the fourth voltage V4 at the sixth timing A6. The sixth timing A6 is the timing when the voltage Vc2 of the plurality of common electrodes 34 of the entire second display device 22b substantially becomes the fourth voltage V4. It is assumed that the voltage Vc2 substantially becomes the fourth voltage V4 when the voltages Vc2 of all the common electrodes 34 become equal to or greater than a first percentage of the fourth voltage V4.

The discharge of the common electrode 34 is started at the fourth timing A4, the voltage Vc2 drops from the fourth voltage V4, and substantially reaches the third voltage V3 at the eighth timing A8. The fourth timing A4 is the timing when the voltage Vc2 of the plurality of common electrodes 34 of the entire second display device 22b substantially becomes the third voltage V3. Suppose that the voltage Vc2 substantially becomes the third voltage V3 when the voltage Vc2 of all the common electrodes 34 becomes a second percentage of the third voltage V3.

The second touch detection circuit 76b detects a second acquisition timing D2 after a predetermined second time t2 has passed since the second timing A2, and a fourth acquisition timing D4 after a second time t2 has passed since the fourth timing A4. , a plurality of second detection values based on respective capacitances of the plurality of common electrodes 34 are obtained. The second touch detection circuit 76b receives touch detection signals from each common electrode 34 between the second timing A2 and the second acquisition timing D2 and between the fourth timing A4 and the fourth acquisition timing D4. A second sensed value is derived based on RX. Each second detection value represents the difference value between the capacitance of the common electrode 34 and the reference capacitance. The second touch detection circuit 76b detects a touch based on the acquired plurality of second detection values. The timing of detecting a touch is not particularly limited. The second touch detection circuit 76b compares the second detection value of each common electrode 34 with a predetermined touch detection threshold, and determines that there is a touch at the position of the common electrode 34 when the second detection value is equal to or greater than the touch detection threshold. judge. The second time t2 can be appropriately set through experiments or simulations so that the second acquisition timing D2 comes after the sixth timing A6 and the fourth acquisition timing D4 comes after the eighth timing A8.

In this manner, the touch detection circuit 76 detects a touch based on the rise timing and fall timing of the touch drive signal TX.

A first period P1 from the first timing A1 to the first acquisition timing D1 and a fifth period P5 from the third timing A3 to the third acquisition timing D3 are the second period from the second timing A2 to the second acquisition timing D2. 3 non-overlapping periods P3. The first period P1 and the fifth period P5 are also non-overlapping with the sixth period P6 from the fourth timing A4 to the fourth acquisition timing D4.

In the illustrated example, the third period P3 starts after the first acquisition timing D1 and ends before the third timing A3. The sixth period P6 starts after the third acquisition timing D3 and ends before the first timing A1. The second drive circuit 74b generates the second touch drive signal TX2 such that these conditions are satisfied.

FIG. 8A shows another example of waveforms of the first touch drive signal TX1 and the voltage Vc1 of the common electrode 34 of the first display device 22a in each touch detection period. FIG. 8B shows another example of waveforms of the second touch drive signal TX2 and the voltage Vc2 of the common electrode 34 of the second display device 22b in each touch detection period.

In this example, the second timing A2 is earlier than the first timing A1, and the fourth timing A4 is earlier than the third timing A3. The third period P3 starts after the third acquisition timing D3 and ends before the first timing A1. The sixth period P6 starts after the first acquisition timing D1 and ends before the third timing A3.

That is, if the first period P1 and the fifth period P5 do not overlap with the third period P3 and also do not overlap with the sixth period P6, the phase of the first touch drive signal TX1 is different from that of the second touch drive signal TX2. It may lead or lag the phase.

Here, a comparative example will be described. FIG. 9A is a diagram for explaining the operation of the display device 22 in the first touch detection period T4a of the display system of the comparative example. FIG. 9B shows the waveform of the first touch drive signal TX1 in each touch detection period of the comparative example, and FIG. 9C shows the waveform of the second touch drive signal TX2 in each touch detection period of the comparative example. show.

The comparative example differs from the present embodiment in that the phase difference between the first touch drive signal TX1 and the second touch drive signal TX2 is zero. That is, in the comparative example, the rising timings and the falling timings of the first touch drive signal TX1 and the second touch drive signal TX2 are the same.

During touch detection in the first touch detection region R1a, the second touch drive signal TX2 is supplied to the entire plurality of common electrodes 34 of the second display device 22b, and touch detection is also performed in the second touch detection region R4b. At this time, noise is generated due to the rise of the second touch drive signal TX2, and there is a possibility that the noise affects the charge of the common electrode 34 of the first touch detection region R1a that started charging in the first period P1. be. In addition, there is a possibility that noise is generated due to the fall of the second touch drive signal TX2, and that noise affects the charge of the common electrode 34 of the first touch detection region R1a that started discharging in the fifth period P5. be.

As a result, the touch detection signal RX of the first touch detection region R1a in the first period P1 and the fifth period P5 is affected, and the first touch detection circuit 76a detects the first acquisition timing D1 and the third acquisition timing D3. , there is a possibility that the first detection value is affected by noise, and therefore, there is a possibility of erroneously detecting contact with the first touch detection region R1a even if the object is not in contact with the first touch detection region R1a.

Although not shown, noise is generated by the first touch drive signal TX1 supplied to the common electrode 34 of the first display device 22a even during the second touch detection period T1b. The noise changes the touch detection signal RX of the second touch detection area R1b, and the second touch detection circuit 76b may erroneously detect that an object has touched the second touch detection area R1b even if the object does not touch the second touch detection area R1b. There is False detection is likely to occur in touch detection of the first touch detection area R1a and the second touch detection area R1b adjacent to the adjacent display device 22, which are most susceptible to noise from the adjacent display device 22. FIG.

In contrast to this comparative example, in the present embodiment, as described above, the first period P1 and the fifth period P5 do not overlap with the third period P3 and also do not overlap with the sixth period P6. Even if noise occurs due to the rise and fall of the touch drive signal TX of one display device 22, the common electrode 34 of the other display device 22 is neither charging nor discharging when the noise occurs. Therefore, the other display device 22 is less likely to be affected by the noise in touch detection.

Therefore, in the touch detection of the first touch detection area R1a adjacent to the second display device 22b and the second touch detection area R1b adjacent to the first display device 22a, erroneous detection can be suppressed more than in the comparative example.

Here, unlike the present embodiment, after the fifth timing A5 at which charging of the plurality of common electrodes 34 of the first display device 22a is substantially completed and before the first acquisition timing D1, the second touch is performed. When the driving signal TX2 rises and noise is generated, the noise can affect the charge of the common electrode 34. FIG. Therefore, the first detection value affected by noise may be acquired at the first acquisition timing D1, and as a result, touch may be erroneously detected. The same applies when the second touch drive signal TX2 rises after the seventh timing A7 and before the third acquisition timing D3. In this embodiment, such erroneous detection can also be suppressed.

Next, the overall operation of the display system 1 configured as above will be described. FIG. 10 is a flowchart showing activation processing of the display system 1 of FIG. The host 10 activates the first display control device 24a and the second display control device 24b (S10), and the first display control device 24a transmits a synchronization signal SY to the second display control device 24b (S12). The second display control device 24b sets the start timing of the second frame period Fb based on the received synchronization signal SY, and displays the second touch drive signal TX2 having a phase difference with respect to the first touch drive signal TX1. 2, the display device 22b is driven (S14), and the process ends.

According to the present embodiment, during the touch detection period, noise occurs in the touch drive signal TX of the other display device 22 from the start of charging or discharging of the common electrode 34 of the one display device 22 to the acquisition timing. Therefore, false detection can be suppressed.

In addition, since the first touch drive signal TX1 and the second touch drive signal TX2 have a phase difference, noise caused by the rise or fall of the first touch drive signal TX1 and noise caused by the rise or fall of the second touch drive signal TX2 occur at different times. Therefore, since these noises are less likely to be added, the radiation of electromagnetic waves from the two display devices 22 caused by the touch drive signal TX can be reduced more than in the comparative example.

(Second embodiment)
The second embodiment differs from the first embodiment in that touch detection is not executed based on the fall timing of the touch drive signal TX. The following description will focus on differences from the first embodiment.

FIG. 11A shows waveforms of the first touch drive signal TX1 and the voltage Vc1 of the common electrode 34 of the first display device 22a in each touch detection period according to the second embodiment. FIG. 11B shows waveforms of the second touch drive signal TX2 and the voltage Vc2 of the common electrode 34 of the second display device 22b in each touch detection period according to the second embodiment.

The first touch detection circuit 76a acquires the first detection value only at the first acquisition timing D1. The second touch detection circuit 76b acquires the second detection value only at the second acquisition timing D2.

The first period P1 and the second period P2 from the third timing A3 to the seventh timing A7 do not overlap with the third period P3. The first period P1 and the second period P2 are also non-overlapping in the fourth period P4 from the fourth timing A4 to the eighth timing A8. The second period P2 and the fourth period P4 can also be called discharge periods.

During the second period P<b>2 , noise may occur during discharging of the common electrode 34 , although the amount of noise decreases over time. The same is true for the fourth period P4. In the present embodiment, the third period P3 does not overlap with the second period P2, so noise generated in the second period P2 does not easily affect charging and touch detection in the third period P3. Since the first period P1 does not overlap with the fourth period P4, noise generated in the fourth period P4 does not easily affect charging and touch detection in the first period P1.

Therefore, erroneous detection can be suppressed when touch detection is performed based only on the rising timing of the touch drive signal TX.

Note that touch detection may be performed based only on the fall timing of the touch drive signal TX. In this case, the first voltage V1 is higher than the second voltage V2, and the third voltage V3 is higher than the fourth voltage V4. The second period P2 and the fourth period P4 can also be called charging periods. Noise may occur during charging of the common electrode 34, but does not easily affect touch detection as described above.

Furthermore, even if one display device 22 performs touch detection based only on the rise timing of the touch drive signal TX, and the other display device 22 performs touch detection based only on the fall timing of the touch drive signal TX, good. In these cases, the flexibility of the configuration of the display system 1 can be improved.

(Third Embodiment)
The third embodiment differs from the first embodiment in that the frequency of the touch drive signal TX is changed based on the detection result of external noise. The following description will focus on differences from the first embodiment.

If the frequency of external noise radiated from electronic devices around the display system 1 is equal to the frequency of the touch drive signal TX, there is a possibility that the accuracy and sensitivity of touch detection will decrease. Therefore, the display system 1 controls so-called frequency hopping according to the amount of external noise. A well-known technique can be used for frequency hopping.

When the supply of the first touch drive signal TX1 is stopped, that is, in the first display period Da, the first touch detection circuit 76a responds to the touch detection signal RX received from the plurality of common electrodes 34 of the first display device 22a. Measure the amount of noise at a plurality of predetermined frequencies included. The multiple frequencies include the frequency of the first touch drive signal TX1. When noise of the frequency of the first touch drive signal TX1 is detected to be at a predetermined level or higher, the first touch detection circuit 76a outputs noise detection information including information on the frequency at which the measured amount of noise is minimum to the first control circuit. 70a.

Based on the noise detection information, the first control circuit 70a controls the first drive circuit 74a to change the frequency of the first touch drive signal TX1 to a frequency that minimizes the amount of noise. The first control circuit 70a outputs, to the second control circuit 70b, a frequency change instruction including information on the frequency with the minimum amount of noise. The second control circuit 70b controls the second drive circuit 74b so as to change the frequency of the second touch drive signal TX2 to a frequency that minimizes the amount of noise based on the frequency change instruction output from the first control circuit 70a. Control.

Under the control of the first control circuit 70a, the first drive circuit 74a supplies the common electrode 34 with a first touch drive signal TX1 having a frequency with the smallest amount of noise, that is, a frequency different from the frequency of noise above a predetermined level. . The second drive circuit 74b supplies the common electrode 34 with a second touch drive signal TX2 having the same frequency as the changed frequency of the first touch drive signal TX1 under the control of the second control circuit 70b. This makes it possible to suppress deterioration in touch detection accuracy and sensitivity due to external noise.

FIG. 12(a) shows the waveform of the first touch drive signal TX1 according to the third embodiment. FIG. 12(b) shows the waveform of the second touch drive signal TX2 according to the third embodiment. These waveforms are waveforms in the first display period Da and are not supplied to the common electrode 34 .

In a state where the first touch drive signal TX1 has the frequency f1, when external noise of frequency f1 or higher is detected at time t10, after time t10, the frequency of the first touch drive signal TX1 is set to the minimum noise amount. is changed to the frequency f2. The lengths of the first period P1 and the fifth period P5 are the same before and after the frequency change, for example.

When the second control circuit 70b receives a frequency change instruction at time t11 while the second touch drive signal TX2 has the frequency f1, the frequency of the second touch drive signal TX2 is changed to the frequency f2 after time t11. The lengths of the third period P3 and the sixth period P6 are, for example, the same before and after the frequency is changed. The second drive circuit 74b performs the second touch driving such that the first period P1 and the fifth period P5 do not overlap with the second period P2 and do not overlap with the sixth period P6 even after the frequency is changed. Generate signal TX2.

According to the present embodiment, even when the frequency of the touch drive signal TX is changed due to detection of external noise, the first period P1 and the fifth period P5 do not overlap with the third period P3, and the third period P3 does not overlap. Since the six periods P6 are also non-overlapping, erroneous detection can be suppressed.

(Fourth embodiment)
The fourth embodiment differs from the first embodiment in that the control device 12 of the host 10 transmits the synchronization signal SY to the first display device 22a and the second display device 22b. The following description will focus on differences from the first embodiment.

FIG. 13 is a block diagram of the display system 1 according to the fourth embodiment. The control device 12 transmits a common synchronization signal SY to the first display control device 24a and the second display control device 24b, for example, at each start timing of the first frame period. The first display controller 24a does not send a synchronization signal to the second display controller 24b.

Based on the synchronization signal SY supplied from the control device 12, the first clock generation circuit 78a generates a first reference clock signal CK1 synchronized with the synchronization signal SY. Based on the synchronization signal SY supplied from the control device 12, the second clock generation circuit 78b generates a second reference clock signal CK2 synchronized with the synchronization signal SY.

FIG. 14 is a flowchart showing activation processing of the display system 1 of FIG. The host 10 activates the first display control device 24a and the second display control device 24b (S20), and transmits the synchronization signal SY to the first display control device 24a and the second display control device 24b (S22). The host 10 transmits the control data CD instructing the phase difference for the first display device 22a to the first display control device 24a (S24). The first display device 22a is driven with the first touch drive signal TX1 according to (S26), and the process ends. Also, in parallel with S24, the host 10 transmits control data CD for instructing the phase difference for the second display device 22b to the second display control device 24b (S28). The second display control device 24b drives the second display device 22b with the second touch drive signal TX2 according to the received control data CD and synchronization signal SY (S30), and ends the process.

According to this embodiment, the flexibility of the configuration of the display system 1 can be improved.

The present invention has been described above based on the embodiments. It should be understood by those skilled in the art that this embodiment is merely an example, and that various modifications can be made to combinations of each component or each treatment process, and such modifications are also within the scope of the present invention. By the way.

For example, the second reference clock signal CK2 is set to a phase difference other than zero with respect to the first reference clock signal CK1, and the second drive circuit 74b generates the second touch drive signal TX2 synchronized with the second reference clock signal CK2. You may In this case, the phase difference between the first reference clock signal CK1 and the second reference clock signal CK2 is set such that the phase difference between the first touch drive signal TX1 and the second touch drive signal TX2 satisfies the above-described relationship. be.

Also, the third embodiment may be combined with the second embodiment. The fourth embodiment may be combined with at least one of the second and third embodiments. A new embodiment resulting from combination has the effects of each of the combined embodiments.

Also, three or more display devices 22 may be arranged adjacently. Although the display controller 24 is included in the display module 20 in the embodiment, the display controller 24 may be included in the host 10 . A frame period may include twice or more touch detection periods as the number of touch detection areas of the display device 22 . In these modified examples, the flexibility of the configuration of the display system 1 can be improved.

Although the two display devices 22 are adjacent to each other in each embodiment of the present disclosure, the display devices 22a and 22b may be in contact with each other via a frame such as a bezel. Further, the display device 22a and the display device 22b may be arranged adjacent to each other with a space of several millimeters to several centimeters interposed therebetween. At this time, the display module 20a and the display module 20b may be arranged in different frames. Also, the display module 20a and the display module 20b may be arranged integrally via a frame. The same is true when three or more display devices 22 are arranged.

Although an in-cell type display device 22 has been described, the display device 22 may be an out-cell type. In this case, the display device 22 includes sensor electrodes dedicated to touch detection, and detects touches using the sensor electrodes in parallel with image display. Even in the case of the out-sell type display device 22, erroneous detection can be suppressed.

One aspect of the present invention is as follows.
[Item 1]
a first display device having a plurality of first sensor electrodes;
a second display device disposed adjacent to the first display device and having a plurality of second sensor electrodes;
a first drive circuit that supplies a first touch drive signal that varies between a first voltage and a second voltage to the plurality of first sensor electrodes;
a second drive circuit that supplies to the plurality of second sensor electrodes a second touch drive signal that varies between a third voltage and a fourth voltage and has a phase difference with respect to the first touch drive signal;
At a first acquisition timing after a predetermined first time has elapsed from a first timing at which the first touch drive signal changes from the first voltage to the second voltage, each of the plurality of first sensor electrodes is electrostatically charged. a first touch detection circuit that acquires a plurality of capacitance-based first detection values and detects a touch of an object to the first display device based on the acquired plurality of first detection values;
Each of the plurality of second sensor electrodes is electrostatically charged at a second acquisition timing after a second predetermined time has elapsed from a second timing at which the second touch drive signal changes from the third voltage to the fourth voltage. a second touch detection circuit that acquires a plurality of capacitance-based second detection values and detects a touch of an object to the second display device based on the acquired plurality of second detection values;
with
A first period from the first timing to the first acquisition timing, and voltages of the plurality of first sensor electrodes from a third timing at which the first touch drive signal changes from the second voltage to the first voltage. is substantially the first voltage, is non-overlapping with a third period from the second timing to the second acquisition timing.
According to this aspect, since the first period does not overlap with the third period, noise generated by the second touch drive signal changing from the third voltage to the fourth voltage in touch detection on the first display device less likely to be affected by Since the first period and the second period are non-overlapping with the third period, in touch detection on the second display device, the first touch drive signal changes from the first voltage to the second voltage or from the second voltage to the first voltage. It is possible to reduce the influence of noise generated by the change. Therefore, erroneous detection can be suppressed.

[Item 2]
A fourth period from a fourth timing at which the second touch drive signal changes from the fourth voltage to the third voltage to a timing at which the voltages of the plurality of second sensor electrodes substantially reach the third voltage, 2. The display system of claim 1, wherein the first time period and the second time period are non-overlapping.
In this case, in touch detection on the first display device, it is possible to reduce the influence of noise generated by the change of the second touch drive signal from the fourth voltage to the third voltage.

[Item 3]
The first touch detection circuit acquires the plurality of first detection values also at a third acquisition timing when the first time longer than the length of the second period has elapsed from the third timing,
3. The display system according to item 2, wherein the first period and a fifth period from the third timing to the third acquisition timing do not overlap with the third period.
In this case, erroneous detection can be suppressed when a touch is detected based on each of the rise and fall of the first touch drive signal.

[Item 4]
The second touch detection circuit acquires the plurality of second detection values also at a fourth acquisition timing after the second time longer than the length of the fourth period has elapsed from the fourth timing,
4. The display system according to item 3, wherein a sixth period from the fourth timing to the fourth acquisition timing does not overlap the first period and the fifth period.
In this case, erroneous detection can be suppressed when a touch is detected based on each of the rise and fall of the second touch drive signal.

[Item 5]
The first drive circuit generates the first touch drive signal based on a first reference clock signal,
5. Any one of items 1 to 4, wherein the second drive circuit generates the second touch drive signal based on a second reference clock signal set to have a phase difference with respect to the first reference clock signal. The display system described in .
In this case, the degree of freedom in configuring the display system can be improved.

[Item 6]
The display according to item 5, wherein the second drive circuit generates the second touch drive signal having the same frequency as that of the first touch drive signal based on the second reference clock signal. system.
In this case, the degree of freedom in configuring the display system can be improved.

[Item 7]
a first clock generation circuit that generates the first reference clock signal and a synchronization signal synchronized with the first reference clock signal;
a second clock generation circuit that generates the second reference clock signal based on the synchronization signal generated by the first clock generation circuit;
7. Display system according to item 5 or 6, characterized in that it comprises:
In this case, the degree of freedom in configuring the display system can be improved.

[Item 8]
a control device that outputs a synchronization signal;
a first clock generation circuit that generates the first reference clock signal based on the synchronization signal output from the control device;
a second clock generation circuit that generates the second reference clock signal based on the synchronization signal output from the control device;
7. Display system according to item 5 or 6, characterized in that it comprises:
In this case, the degree of freedom in configuring the display system can be improved.

[Item 9]
The first drive circuit supplies the first touch drive signal during a predetermined touch detection period and stops supplying the first touch drive signal outside the touch detection period,
The first touch detection circuit detects noise of the frequency of the first touch drive signal included in the signal received from the first sensor electrode when the supply of the first touch drive signal is stopped,
When noise is detected in the first touch detection circuit, the first drive circuit supplies the first touch drive signal with a frequency different from the frequency of the noise, and the second drive circuit is changed to providing the second touch drive signal having the same frequency as the frequency of the first touch drive signal;
9. The method according to any one of items 1 to 8, wherein the first period and the second period do not overlap with the third period even when noise is detected by the first touch detection circuit. display system.
In this case, even when noise is detected by the first touch detection circuit and the frequency of the touch drive signal is changed, erroneous detection can be suppressed.

[Item 10]
a first display device having a plurality of first sensor electrodes;
a second display device disposed adjacent to the first display device and having a plurality of second sensor electrodes;
a first drive circuit that supplies a first touch drive signal that varies between a first voltage and a second voltage to the plurality of first sensor electrodes;
a second drive circuit that supplies to the plurality of second sensor electrodes a second touch drive signal that varies between a third voltage and a fourth voltage and has a phase difference with respect to the first touch drive signal;
At a first acquisition timing after a predetermined first time has elapsed from a first timing at which the first touch drive signal changes from the first voltage to the second voltage, each of the plurality of first sensor electrodes is electrostatically charged. a first touch detection circuit that acquires a plurality of capacitance-based first detection values and detects a touch of an object to the first display device based on the acquired plurality of first detection values;
Each of the plurality of second sensor electrodes is electrostatically charged at a second acquisition timing after a second predetermined time has elapsed from a second timing at which the second touch drive signal changes from the third voltage to the fourth voltage. a second touch detection circuit that acquires a plurality of capacitance-based second detection values and detects a touch of an object to the second display device based on the acquired plurality of second detection values;
A control method in a display system comprising
A first period from the first timing to the first acquisition timing, and voltages of the plurality of first sensor electrodes from a third timing at which the first touch drive signal changes from the second voltage to the first voltage. substantially becomes the first voltage, and the third period from the second timing to the second acquisition timing does not overlap with the first driving circuit, the second A control method, comprising: controlling a drive circuit, the first touch detection circuit and the second touch detection circuit.
According to this aspect, erroneous detection can be suppressed.

REFERENCE SIGNS LIST 1 display system 12 control device 22 display device 22a first display device 22b second display device 74a first drive circuit 74b second drive circuit 76 touch detection circuit 76a 1st touch detection circuit 76b 2nd touch detection circuit 78a 1st clock generation circuit 78b 2nd clock generation circuit TX1 1st touch drive signal TX2 2nd touch drive signal.

Claims (10)

a first display device having a plurality of first sensor electrodes;
a second display device disposed adjacent to the first display device and having a plurality of second sensor electrodes;
a first drive circuit that supplies a first touch drive signal that varies between a first voltage and a second voltage to the plurality of first sensor electrodes;
a second drive circuit that supplies to the plurality of second sensor electrodes a second touch drive signal that varies between a third voltage and a fourth voltage and has a phase difference with respect to the first touch drive signal;
At a first acquisition timing after a predetermined first time has elapsed from a first timing at which the first touch drive signal changes from the first voltage to the second voltage, each of the plurality of first sensor electrodes is electrostatically charged. a first touch detection circuit that acquires a plurality of capacitance-based first detection values and detects a touch of an object to the first display device based on the acquired plurality of first detection values;
Each of the plurality of second sensor electrodes is electrostatically charged at a second acquisition timing after a second predetermined time has elapsed from a second timing at which the second touch drive signal changes from the third voltage to the fourth voltage. a second touch detection circuit that acquires a plurality of capacitance-based second detection values and detects a touch of an object to the second display device based on the acquired plurality of second detection values;
with
A first period from the first timing to the first acquisition timing, and voltages of the plurality of first sensor electrodes from a third timing at which the first touch drive signal changes from the second voltage to the first voltage. is substantially the first voltage, is non-overlapping with a third period from the second timing to the second acquisition timing. A fourth period from a fourth timing at which the second touch drive signal changes from the fourth voltage to the third voltage to a timing at which the voltages of the plurality of second sensor electrodes substantially reach the third voltage, 2. The display system of claim 1, wherein the first time period and the second time period are non-overlapping. The first touch detection circuit acquires the plurality of first detection values also at a third acquisition timing when the first time longer than the length of the second period has elapsed from the third timing,
3. The display system according to claim 2, wherein the first period and a fifth period from the third timing to the third acquisition timing do not overlap with the third period. The second touch detection circuit acquires the plurality of second detection values also at a fourth acquisition timing after the second time longer than the length of the fourth period has elapsed from the fourth timing,
4. The display system according to claim 3, wherein a sixth period from said fourth timing to said fourth acquisition timing does not overlap with said first period and said fifth period. The first drive circuit generates the first touch drive signal based on a first reference clock signal,
5. The second touch drive signal according to any one of claims 1 to 4, wherein the second drive circuit generates the second touch drive signal based on a second reference clock signal having a phase difference with respect to the first reference clock signal. a display system according to claim 1. 6. The method of claim 5, wherein the second drive circuit generates the second touch drive signal having the same frequency as that of the first touch drive signal based on the second reference clock signal. display system. a first clock generation circuit that generates the first reference clock signal and a synchronization signal synchronized with the first reference clock signal;
a second clock generation circuit that generates the second reference clock signal based on the synchronization signal generated by the first clock generation circuit;
7. A display system according to claim 5 or 6, comprising: a control device that outputs a synchronization signal;
a first clock generation circuit that generates the first reference clock signal based on the synchronization signal output from the control device;
a second clock generation circuit that generates the second reference clock signal based on the synchronization signal output from the control device;
7. A display system according to claim 5 or 6, comprising: The first drive circuit supplies the first touch drive signal during a predetermined touch detection period and stops supplying the first touch drive signal outside the touch detection period,
The first touch detection circuit detects noise of the frequency of the first touch drive signal included in the signal received from the first sensor electrode when the supply of the first touch drive signal is stopped,
When noise is detected in the first touch detection circuit, the first drive circuit supplies the first touch drive signal with a frequency different from the frequency of the noise, and the second drive circuit is changed to providing the second touch drive signal having the same frequency as the frequency of the first touch drive signal;
9. The method according to any one of claims 1 to 8, wherein the first period and the second period do not overlap with the third period even if noise is detected by the first touch detection circuit. display system. a first display device having a plurality of first sensor electrodes;
a second display device disposed adjacent to the first display device and having a plurality of second sensor electrodes;
a first drive circuit that supplies a first touch drive signal that varies between a first voltage and a second voltage to the plurality of first sensor electrodes;
a second drive circuit that supplies to the plurality of second sensor electrodes a second touch drive signal that varies between a third voltage and a fourth voltage and has a phase difference with respect to the first touch drive signal;
At a first acquisition timing after a predetermined first time has elapsed from a first timing at which the first touch drive signal changes from the first voltage to the second voltage, each of the plurality of first sensor electrodes is electrostatically charged. a first touch detection circuit that acquires a plurality of capacitance-based first detection values and detects a touch of an object to the first display device based on the acquired plurality of first detection values;
Each of the plurality of second sensor electrodes is electrostatically charged at a second acquisition timing after a predetermined second time has elapsed from a second timing at which the second touch drive signal changes from the third voltage to the fourth voltage. a second touch detection circuit that acquires a plurality of capacitance-based second detection values and detects a touch of an object to the second display device based on the acquired plurality of second detection values;
A control method in a display system comprising
A first period from the first timing to the first acquisition timing, and voltages of the plurality of first sensor electrodes from a third timing at which the first touch drive signal changes from the second voltage to the first voltage. substantially becomes the first voltage, and the third period from the second timing to the second acquisition timing does not overlap with the first driving circuit, the second A control method, comprising: controlling a drive circuit, the first touch detection circuit and the second touch detection circuit.

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