JP7373797B2 - Display system, control device, control method and display device - Google Patents

Description

The present disclosure relates to a display system, a control device, a control method, and a display device having a touch detection function.

An in-cell display device is known in which a touch sensor for detecting a user's touch position is built into a display panel (for example, see Patent Document 1). In this display device, a common electrode for supplying a common voltage to pixels of a liquid crystal display panel is divided into a plurality of parts, and these common electrodes are also used as touch sensor electrodes. A common voltage is supplied to the plurality of common electrodes during the image display period, and a touch drive signal for touch detection is supplied to the plurality of common electrodes during the touch detection period.

International Publication No. 2018/123813

Further improvements are required in in-cell display devices.

In order to solve the above problems, a display system according to an aspect of the present disclosure includes a display device having a plurality of common electrodes that are shared for image display and touch detection, and a touch drive signal is supplied to each of the plurality of common electrodes. The display device includes a drive circuit and a touch detection circuit that detects a touch of an object to the display device based on touch detection signals received from each of the plurality of common electrodes. In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which a touch detection circuit detects a touch are arranged alternately, and the display device has a plurality of common electrodes arranged in a plurality of groups. It includes a divided first touch detection area and a plurality of second touch detection areas. The touch detection circuit detects a touch in the same first touch detection area and in a different second touch detection area for each touch detection period in a plurality of touch detection periods.

Another aspect of the present disclosure is a control device. This device is a control device that controls a display device that has a plurality of common electrodes that are shared for image display and touch detection, and includes a drive circuit that supplies touch drive signals to each of the plurality of common electrodes, and a drive circuit that supplies touch drive signals to each of the plurality of common electrodes. A touch detection circuit detects a touch of an object to the display device based on a touch detection signal received from each of the electrodes. In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which a touch detection circuit detects a touch are arranged alternately, and the display device has a plurality of common electrodes arranged in a plurality of groups. It includes a divided first touch detection area and a plurality of second touch detection areas. The touch detection circuit detects a touch in the same first touch detection area and in a different second touch detection area for each touch detection period in a plurality of touch detection periods.

Yet another aspect of the present disclosure is a control method. This method is a control method for a display device having a plurality of common electrodes that are shared for image display and touch detection, and includes the steps of supplying a touch drive signal to each of the plurality of common electrodes; and detecting a touch of an object on the display device based on a touch detection signal received from the display device. In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which a touch is detected are arranged alternately, and the display device has a plurality of common electrodes divided into a plurality of groups. It includes a first touch detection area and a plurality of second touch detection areas. In the step of detecting a touch, a touch is detected in the same first touch detection area and a different second touch detection area for each touch detection period in a plurality of touch detection periods.

A display system according to another aspect of the present disclosure includes a display device having a plurality of common electrodes shared for image display and touch detection, a drive circuit that supplies touch drive signals to each of the plurality of common electrodes, and a plurality of common electrodes. A touch detection circuit detects a touch of an object to the display device based on a touch detection signal received from each of the electrodes. In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which a touch detection circuit detects a touch are arranged alternately, and the display device has a plurality of common electrodes arranged in a plurality of groups. It includes a plurality of divided touch detection areas. When a touch is not detected, the touch detection circuit detects a touch in a different touch detection area for each touch detection period, and when a touch is detected in one of the plurality of touch detection areas, the touch detection circuit detects a touch when a touch is detected. A touch is detected continuously in the area in a plurality of touch detection periods.

Another aspect of the present disclosure is a control device. This device is a control device that controls a display device that has a plurality of common electrodes that are shared for image display and touch detection, and includes a drive circuit that supplies touch drive signals to each of the plurality of common electrodes, and a drive circuit that supplies touch drive signals to each of the plurality of common electrodes. A touch detection circuit detects a touch of an object to the display device based on a touch detection signal received from each of the electrodes. In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which a touch detection circuit detects a touch are arranged alternately, and the display device has a plurality of common electrodes arranged in a plurality of groups. It includes a plurality of divided touch detection areas. When a touch is not detected, the touch detection circuit detects a touch in a different touch detection area for each touch detection period, and when a touch is detected in one of the plurality of touch detection areas, the touch detection circuit detects a touch when a touch is detected. A touch is detected continuously in the area in a plurality of touch detection periods.

Yet another aspect of the present disclosure is a control method. This method is a control method for a display device having a plurality of common electrodes that are shared for image display and touch detection, and includes the steps of supplying a touch drive signal to each of the plurality of common electrodes; and detecting a touch of an object on the display device based on a touch detection signal received from the display device. In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which a touch is detected are arranged alternately, and the display device has a plurality of common electrodes divided into a plurality of groups. Contains multiple touch detection areas. In the step of detecting a touch, if a touch is not detected, a touch is detected in a different touch detection area for each touch detection period, and if a touch is detected in one of the plurality of touch detection areas, a touch is detected. A touch is continuously detected in a touch detection area in a plurality of touch detection periods.

Further improvements can be achieved by the above aspects.

FIG. 1 is a block diagram of a display system according to a first embodiment. 2 is a diagram schematically showing a circuit configuration of the display device in FIG. 1. FIG. FIG. 3 is a top view showing the arrangement of the common electrode in FIG. 2; 2 is a diagram illustrating the operation of the display device in FIG. 1. FIG. 5(a) shows the timing of the unit frame period and the waveform of the touch drive signal in the display device of FIG. 1, and FIG. 5(b) shows the rotary operation position of the dial at each timing of FIG. 5(a). It is a diagram. FIG. 6(a) is a diagram explaining the operation of the display device of the first comparative example, FIG. 6(b) is a diagram showing the timing of the unit frame period of the first comparative example, and FIG. 6(c) is a diagram illustrating the operation of the display device of the first comparative example. 6(b) is a diagram showing the rotational operation position of the dial at each timing in FIG. 6(b). 2 is a flowchart showing touch detection processing of the display system of FIG. 1. FIG. FIG. 8(a) is a diagram illustrating the operation of the display device according to the second embodiment, and FIG. 8(b) is a diagram illustrating the timing of a unit frame period in the display device of FIG. 8(a). It is. 7 is a flowchart showing touch detection processing of the display system according to the second embodiment. FIG. 10(a) is a diagram explaining the operation of the display device according to the third embodiment, and FIG. 10(b) shows the timing of a unit frame period in the display device of FIG. 10(a), FIG. 10(c) is a diagram showing the operation position of the handle of the slide bar at each timing in FIG. 10(b). 12 is a flowchart illustrating touch detection processing of a display system according to a third embodiment. FIG. 7 is a diagram illustrating the operation of the display device according to the fifth embodiment. FIG. 13(a) shows the timing of the unit frame period and the waveform of the touch drive signal when no touch is detected in the display device according to the fifth embodiment, and FIG. 13(b) shows the waveform of the touch drive signal in the display device according to the fifth embodiment. FIG. 4 is a diagram showing the timing of a unit frame period and the waveform of a touch drive signal when a touch is detected in the display device according to the embodiment. It is a flowchart which shows the touch detection process of the display system concerning a 5th embodiment. It is a flowchart which shows the touch detection process of the display system based on 6th Embodiment. It is a flowchart which shows the touch detection process of the display system concerning a 7th embodiment. FIG. 2 is a longitudinal cross-sectional view of the display device of FIG. 1;

(Findings that formed the basis of this disclosure)
Before specifically explaining the embodiments, the basic knowledge will be explained. In an in-cell touch display, one frame period is time-divided into a plurality of image display periods and a plurality of touch detection periods. Then, by dividing one screen into multiple touch detection areas (also called scan blocks) and detecting touches in different touch detection areas for each touch detection period, touch detection for one screen is executed in one frame period. . By repeating touch detection for one screen multiple times in one frame period, the time between consecutive touch detections at one position within the screen can be shortened.

In such a configuration, the higher the resolution of the display, the more limited the time that can be allocated to the touch detection period in a frame period of a certain length. Therefore, it is difficult to increase the number of repetitions of touch detection for one screen in one frame period, and it is necessary to shorten the time between consecutive touch detections at a certain position on the screen, in other words, to speed up the response of touch detection. The inventor of the present invention has discovered that it is difficult to make a difference. In order to solve this problem, a display system according to the present disclosure is configured as follows.

Hereinafter, the same or equivalent components, members, and steps shown in each drawing will be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. Further, the dimensions of members in each drawing are shown enlarged or reduced as appropriate to facilitate understanding.

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

The display system 1 includes a host 10 and a display module 20. The host 10 executes various functions such as radio, car navigation, and Bluetooth (registered trademark) communication, and also controls the display module 20. The host 10 includes a control device 12 .

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

The display module 20 includes a display device 22 and a control device 24. The display device 22 is used, for example, as a center display in the vehicle interior on which a car navigation screen or the like is displayed.

The display device 22 is an in-cell IPS (In Plane Switching) type liquid crystal display device, configured as a touch display, and 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. 1. FIG. 2 also shows the schematic arrangement 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, . . . extending in the column direction, a plurality of pixel switching elements 30, and a plurality of pixels. It includes 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, corresponding 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 liquid crystal layer is controlled by the electric field between the pixel electrode 32 and the common electrode 34. The common electrode 34 is shared for image display and touch detection. Therefore, the number of electrode layers can be reduced to make the display device 22 thinner. The common electrode 34 can also be called a sensor electrode.

FIG. 3 is a top view showing the arrangement of the common electrode 34 of FIG. 2. The plurality of common electrodes 34 are arranged in a matrix. Each common electrode 34 is connected to the control device 24 by a signal line 36.

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

Return to Figure 1. The control device 24 is configured as an IC, for example, and controls the display device 22 according to control data CD and image data DD from the host 10. The control device 24 includes a control circuit 70 , a first drive circuit 72 , a second drive circuit 74 , and a touch detection circuit 76 .

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

The control circuit 70 controls the first drive circuit 72 so that one frame of the display image is drawn on the display device 22 in a unit frame period (one frame period), and touch detection for one screen is executed at least once. The second drive circuit 74 and touch detection circuit 76 are controlled. The unit frame period can also be called a vertical synchronization period. Details of the unit frame period will be described later.

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

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

The first drive circuit 72 supplies a reference clock signal to the second drive circuit 74. The second drive circuit 74 generates a reference voltage VCOM, which is a predetermined fixed voltage, and a touch drive signal TX synchronized with the reference clock signal under the control of the control circuit 70. Note that the touch drive signal TX may be a rectangular wave or a sine wave. The second drive circuit 74 supplies the reference voltage VCOM or the touch drive signal TX to the plurality of common electrodes 34 throughout the display device 22 via the signal line 36 in FIG.

The touch detection circuit 76 detects a touch of an object to the display device 22. Under the control of the control circuit 70, the touch detection circuit 76 responds to each common electrode 34 based on the touch detection signal RX received from the common electrode 34 when the touch drive signal TX is supplied to each common electrode 34. Detects the touch of an object at the location.

The touch detection circuit 76 integrates the touch detection signal RX received from each common electrode 34, and derives the difference between the integrated value and the reference value as a detected value at each pulse timing of the touch drive signal TX. Regarding the touch detection signal RX received from one common electrode 34 in one touch detection period, a number of detection values equal to the number of pulses of the touch drive signal TX in one touch detection period is obtained. Each detected value represents a difference value between the capacitance of the common electrode 34 and the reference capacitance. The larger the amount of change in the capacitance of the common electrode 34 due to the touch of the object, the larger the detected value. If there is no touch and the amount of change in capacitance of the common electrode 34 is zero, the detected value is zero. The touch detection circuit 76 derives the sum of a plurality of detection values in one touch detection period for each touch detection signal RX received from the common electrode 34.

The touch detection circuit 76 compares the sum of detection values based on the touch detection signal RX received from each common electrode 34 with a predetermined touch detection threshold, and when the sum of the detection values is equal to or greater than the touch detection threshold, the touch detection circuit 76 detects the common electrode 34. It is determined that there is a touch at the position. This corresponds to a touch being detected. The touch detection circuit 76 detects the touch position within the screen based on the position of the common electrode 34 determined to be touched. Touch detection circuit 76 outputs information about the detected touch position to control circuit 70 .

The control circuit 70 derives coordinate data TD of the touch position based on the touch position information from the touch detection circuit 76 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 configuration of the control device 12 and the control circuit 70 can be realized by cooperation of hardware resources and software resources, or by only hardware resources. Analog elements, microcomputers, DSPs, ROMs, RAMs, FPGAs, and other LSIs can be used as hardware resources. Programs such as firmware can be used as software resources.

The control of the display device 22 by the control circuit 70 and the operation of the display device 22 will be specifically described below. The control circuit 70 alternately displays a partial image on one of the plurality of display areas on the screen and performs partial touch detection on a part of the plurality of touch detection areas on the screen, thereby controlling the image display and the display area. Control touch detection in a time-sharing manner.

FIG. 4 is a diagram illustrating the operation of the display device 22 of FIG. 1. The display device 22 includes two first touch detection areas R5, R5 and four second touch detection areas R1, R2, R3, R4 in which a plurality of common electrodes 34 in the screen are divided into a plurality of groups.

One first touch detection area R5 is located at the lower left corner of the screen, and the other first touch detection area R5 is located at the lower right corner of the screen. The second touch detection areas R1, R2, R3, and R4 are lined up in order from left to right in the horizontal direction when viewed from the viewer. A plurality of common electrodes 34 throughout the display device 22 are arranged in each of the first touch detection regions R5, R5 and the second touch detection regions R1 to R4. The number of common electrodes 34 arranged in each touch detection area shown in FIG. 4 is an example. The number of first touch detection areas of the display device 22 is not limited to "2", and the number of second touch detection areas is not limited to "4".

The display system 1 includes a rotatable dial 100 arranged in each of the first touch detection areas R5, R5 on the display surface of the display device 22. The dial 100 is, for example, a dial for setting the temperature of a vehicle's air conditioner.

Each of the dials 100 is rotatable about a rotation axis fixed to the display surface of the display device 22 in response to a user's operation. A conductor (not shown) is arranged in a portion of the dial 100 facing the display surface of the display device 22. As the dial 100 rotates, the conductor also rotates around the rotation axis. The touch detection circuit 76 detects the rotational operation position of the dial 100, which is the position of the conductor, as a touch position.

The touch detection circuit 76 includes an A/D converter 761 and switches SW1, SW2, SW3, SW4, and SW5. Although not shown, each switch has multiple sets of input terminals and output terminals. In FIG. 4, the connection between the common electrode 34 and the signal line 36 is omitted to simplify the drawing.

A plurality of input terminals of the switch SW1 are connected one-to-one to a plurality of common electrodes 34 included in the second touch detection region R1 via a signal line 36. A plurality of input terminals of the switch SW2 are connected one-to-one to a plurality of common electrodes 34 included in the second touch detection region R2 via a signal line 36. A plurality of input terminals of the switch SW3 are connected one-to-one to a plurality of common electrodes 34 included in the second touch detection region R3 via a signal line 36. A plurality of input terminals of the switch SW4 are connected one-to-one to a plurality of common electrodes 34 included in the second touch detection region R4 via a signal line 36. A plurality of input terminals of the switch SW5 are connected one-to-one to a plurality of common electrodes 34 included in the first touch detection region R5 via a signal line 36.

The output terminals of switches SW1 to SW5 are connected to the input port of A/D converter 761. Since the number of input ports of the A/D converter 761 is smaller than the number of common electrodes 34 in the screen, the common electrodes 34 connected to the input ports of the A/D converter 761 are switched by a switch. The number of input ports of the A/D converter 761 is equal to the number of input signals that the A/D converter 761 can process simultaneously, and can also be called the number of input channels.

5(a) shows the timing of the unit frame period Fa in the display device 22 of FIG. 1 and the waveform of the touch drive signal TX, and FIG. 5(b) shows the rotation of the dial 100 at each timing of FIG. 5(a). Indicates the operating position.

The example shown in FIG. 5A is an example in which one image is displayed in a unit frame period (one frame period) Fa, and touch detection for one screen is executed twice. In this embodiment, since the display device 22 is assumed to display images driven at 60 Hz, the unit frame period Fa is set to approximately 16.7 (=1/60) ms. Since touch detection for one screen is executed twice in the unit frame period Fa, it is executed at a cycle of approximately 8.3 (=1/120) ms.

The unit frame period Fa is divided into two subframe periods Fb. Each subframe period Fb includes four display periods Da and four touch detection periods T1a, T2a, T3a, and T4a. The display period Da and the touch detection period are arranged alternately. In each subframe period Fb, a display period Da, a touch detection period T1a, a display period Da, a touch detection period T2a, a display period Da, a touch detection period T3a, a display period Da, and a touch detection period T4a are arranged in this order. The number of display periods Da and the number of touch detection periods in the unit frame period Fa are not limited to "8".

The display device 22 displays 1/8 of one frame every display period Da. One frame is displayed by eight display periods Da of the unit frame period Fa. Specifically, during the display period Da, the first drive circuit 72 supplies a source signal SS to a plurality of source lines, supplies a gate signal GS to a target gate line, and the second drive circuit 74 supplies a plurality of common source lines with a gate signal GS. A reference voltage VCOM is supplied to the electrode 34. The second drive circuit 74 stops supplying the touch drive signal TX during the display period Da.

The second drive circuit 74 supplies a touch drive signal TX to the plurality of common electrodes 34 in the first touch detection region R5 and the second touch detection regions R1 to R4 during each touch detection period. The second drive circuit 74 stops supplying the reference voltage VCOM during the touch detection period.

The control circuit 70 makes a different one of the switches SW1, SW2, SW3, and SW4 conductive for each touch detection period while keeping the switch SW5 conductive. The touch detection signal RX input to the conductive switch is output to the A/D converter 761. The A/D converter 761 converts the analog touch detection signal RX input via the switch into a digital touch detection signal.

During the touch detection period T1a, the touch detection circuit 76 detects the first touch detection area R5 and the second touch detection area R1 based on the touch detection signals RX received from the plurality of common electrodes 34 of the first touch detection area R5 and the second touch detection area R1. A touch of an object to the second touch detection area R1 is detected.

During the touch detection period T2a, the touch detection circuit 76 detects the first touch detection area R5 and the second touch detection area R2 based on the touch detection signals RX received from the plurality of common electrodes 34 of the first touch detection area R5 and the second touch detection area R2. A touch of an object to the second touch detection area R2 is detected.

During the touch detection period T3a, the touch detection circuit 76 detects the first touch detection area R5 and the second touch detection area R3 based on the touch detection signals RX received from the plurality of common electrodes 34 of the first touch detection area R5 and the second touch detection area R3. A touch of an object to the second touch detection area R3 is detected.

During the touch detection period T4a, the touch detection circuit 76 detects the first touch detection area R5 and the second touch detection area R4 based on the touch detection signals RX received from the plurality of common electrodes 34 of the first touch detection area R5 and the second touch detection area R4. A touch of an object to the second touch detection area R4 is detected.

In this way, the touch detection circuit 76 detects a touch in the same first touch detection area R5 in each of the plurality of touch detection periods and in the second touch detection area that is different for each touch detection period. That is, the touch detection circuit 76 fixes the first touch detection area R5 to be detected, and sequentially changes the second touch detection area to be detected. Touch detection for one screen is executed twice during the eight touch detection periods of the unit frame period Fa. Note that the display device 22 may include the same number of touch detection areas as the number of touch detection periods in the unit frame period Fa, and in this case, touch detection for one screen is performed by a plurality of touch detection periods in the unit frame period Fa. Executed once.

Here, a first comparative example will be explained. FIG. 6(a) is a diagram illustrating the operation of the display device 22 of the first comparative example, and FIG. 6(b) shows the timing of the unit frame period Fa of the first comparative example. c) shows the rotational operation position of the dial 100 at each timing in FIG. 6(b).

In the first comparative example, the first touch detection area R5 is not provided, and the entire plurality of common electrodes 34 in the display device 22 are grouped into second touch detection areas R1 to R4. Different from the form. That is, the common electrode 34 that overlaps with the dial 100 on the left side is included in the second touch detection area R1, and the common electrode 34 that overlaps with the dial 100 on the right side is included in the second touch detection area R4.

In each of the plurality of touch detection periods, touch detection is performed in a second touch detection area that is different for each touch detection period. Touch detection on the left dial 100 is performed during the touch detection period T1a, and is performed every 8.3 ms during the subframe period Fb. The same applies to touch detection on the dial 100 on the right side. As shown in FIG. 6(c), for example, after the rotary operation position "25" of the left dial 100 is detected during the touch detection period T1a, the rotary operation position moves to "28" within 8.3 ms. , rotational operation positions "26" and "27" are not detected, and rotational operation position "28" is detected in the next touch detection period T1a. Therefore, when the rotation operation of the dial 100 is performed at a relatively high speed, it may not be possible to detect a plurality of consecutive rotation operation positions.

In contrast to this first comparative example, in the present embodiment, since a touch is detected in the first touch detection region R5 in each of the plurality of touch detection periods as described above, the first touch detection region R5 in which the dial 100 is arranged is The response of touch detection in the touch detection area R5 can be made faster than in the first comparative example. In this example, touch detection in the first touch detection area R5 is performed at approximately 2.1 ms intervals. Therefore, as shown in FIG. 5(b), if the rotary operation position of the dial 100 moves from "25" to "28" during the subframe period, the rotary operation positions "25", "26", "27" ” and “28” are detected. Therefore, it is easier to detect a plurality of consecutive rotation operation positions than in the first comparative example.

Next, the overall operation of the display system 1 with the above configuration will be explained. FIG. 7 is a flowchart showing touch detection processing of the display system 1 of FIG. 1. The touch detection circuit 76 detects a touch in the first touch detection area R5 and the second touch detection area R1 (S10), detects a touch in the first touch detection area R5 and the second touch detection area R2 (S12), A touch is detected in the first touch detection area R5 and the second touch detection area R3 (S14), and a touch is detected in the first touch detection area R5 and the second touch detection area R4 (S16). The control circuit 70 calculates the coordinates (S18) and returns to S10. The control circuit 70 may calculate the coordinates in each of S10 to S16.

According to this embodiment, the touch detection response of the first touch detection area R5 can be made faster than that of the second touch detection area. Therefore, the response of detecting the rotational operation position of the dial 100 can be sped up.

Note that FIG. 4 shows an example in which the number of common electrodes 34 in the second touch detection area R1 is smaller than the number of common electrodes 34 in the second touch detection area R2 by the number of common electrodes 34 in the first touch detection area R5. However, the number of common electrodes 34 in each of the second touch detection regions R1 to R4 may be equal or approximately equal. In this case, the number of common electrodes 34 of the first touch detection area R5 and the second touch detection area R2 that are connected to the A/D converter 761 at the same time, the number of common electrodes 34 of the first touch detection area R5 and the second touch detection area R3 Since the number of input ports of the A/D converter 761 can be reduced compared to the embodiment, it is possible to cope with a case where the number of input ports of the A/D converter 761 is smaller.

(Second embodiment)
The second embodiment differs from the first embodiment in that the first touch detection area is set at the position where a touch is detected. Hereinafter, differences from the first embodiment will be mainly explained.

The control circuit 70 switches the division pattern of the plurality of common electrodes 34 to set different touch detection areas until a touch is detected and when a touch is detected.

When a touch is not detected, the control circuit 70 sets second touch detection regions R1 to R4 in which the plurality of common electrodes 34 in the screen are equally divided into four groups. If a touch is not detected, the touch detection circuit 76 detects a touch in a second touch detection area that is different for each touch detection period in each of the plurality of touch detection periods T1a to T4a.

FIG. 8(a) is a diagram explaining the operation of the display device 22 according to the second embodiment, and FIG. 8(b) is a diagram illustrating the timing of the unit frame period Fa in the display device 22 of FIG. 8(a). shows. FIGS. 8A and 8B show an example in which a touch is detected within the second touch detection region R2 during the touch detection period T2a.

When a touch is detected, the control circuit 70 sets a first touch detection region R5 that includes the common electrode 34 at the position where the touch was detected. The control circuit 70 may set a first touch detection area R5 that also includes a predetermined number of common electrodes 34 around the common electrode 34 at the position where the touch is detected. The predetermined number can be appropriately determined by experiment or simulation depending on the size of the common electrode 34, etc. so that sliding of the touched object can be detected. In the illustrated example, a first touch detection region R5 including four common electrodes 34 is set within the second touch detection region R2. The control circuit 70 removes the common electrode 34 included in the set first touch detection area R5 from the second touch detection area R2.

When a touch is detected, the touch detection circuit 76 detects the touch in the same first touch detection area R5 in each of the plurality of touch detection periods and in a second touch detection area that is different for each touch detection period. In the illustrated example, the touch detection circuit 76 detects a touch in the first touch detection area R5 and the second touch detection area R3 in the next touch detection period T3a after the touch detection period T2a in which the touch was detected, and then In the touch detection period T4a, a touch is detected in the first touch detection area R5 and the second touch detection area R4. The touch detection circuit 76 detects a touch in the first touch detection area R5 and the second touch detection area R1 in the next touch detection period T1a, and in the next touch detection period T2a, the touch detection circuit 76 detects a touch in the first touch detection area R5 and the second touch detection area R1. A touch is detected in the second touch detection area R2.

Therefore, touch detection is performed in the first touch detection area R5 at a shorter cycle than in the second touch detection area R1 and the like. Therefore, when the touched finger is released or the touched finger is slid, it can be detected at an earlier timing than in the first comparative example described above.

When the control circuit 70 sets the first touch detection area R5 including the common electrode 34 at the position where the touch is detected, when the detection of the touch in the first touch detection area R5 is interrupted, the control circuit 70 sets the first touch detection area R5. is released, the common electrode 34 of the first touch detection area R5 is included in the original second touch detection area, and a touch is detected in a different second touch detection area for each touch detection period. That is, when the detection of a touch in the first touch detection area R5 is interrupted, the control circuit 70 performs the same control as when no touch is detected. Thereby, when touch detection is interrupted, the number of touch detection signals RX processed by the touch detection circuit 76 in one touch detection period can be reduced.

Next, the overall operation of the display system 1 with the above configuration will be explained. FIG. 9 is a flowchart showing touch detection processing of the display system 1 according to the second embodiment. If no touch is detected (N in S20), the control circuit 70 returns to S20. When a touch is detected (Y in S20), the control circuit 70 sets a first touch detection area R5 (S22). The subsequent processes from S10 to S18 are the same as in the first embodiment.

According to this embodiment, it is possible to speed up the response of touch detection near the position where a touch is detected.

Note that in FIG. 8A, the number of common electrodes 34 in the second touch detection area R2 is smaller than the number of common electrodes 34 in the second touch detection area R1 by the number of common electrodes 34 in the first touch detection area R5. Although an example has been shown, the number of common electrodes 34 in each of the second touch detection regions R1 to R4 may be equal or approximately equal. In this case, when the control circuit 70 sets the first touch detection area R5 including the common electrode 34 at the position where the touch is detected, the control circuit 70 evenly divides the common electrodes 34 other than the first touch detection area R5 into a plurality of groups. After dividing, a plurality of second touch detection regions R1 to R4 are reset. As a result, the maximum number of common electrodes 34 connected to the A/D converter 761 during one touch detection period can be reduced compared to the second embodiment, so when the number of input ports of the A/D converter 761 is smaller, can also be handled. When the detection of a touch in the first touch detection area R5 is interrupted, the control circuit 70 cancels the setting of the first touch detection area R5 and returns it to the plurality of second touch detection areas R1 to R4 before being reset.

Furthermore, the control circuit 70 does not need to cancel the setting of the first touch detection area R5 even if touch detection in the first touch detection area R5 is interrupted. In this case, if a new touch is detected after touch detection in the first touch detection area R5 is interrupted, the control circuit 70 cancels the setting of the existing first touch detection area R5 and detects a touch. What is necessary is to reset the first touch detection area R5 including the common electrode 34 at the position where the touch detection area has been moved. In this case, control can be simplified.

(Third embodiment)
The third embodiment differs from the first embodiment in that a GUI (Graphical User Interface) is displayed in the first touch detection area R5. Hereinafter, differences from the first embodiment will be mainly explained.

FIG. 10(a) is a diagram for explaining the operation of the display device 22 according to the third embodiment, and FIG. 10(b) is a diagram illustrating the timing of the unit frame period Fa in the display device 22 of FIG. 10(a). 10(c) shows the operating position of the handle 104 of the slide bar 102 at each timing in FIG. 10(b).

The first touch detection area R5 is a rectangular area extending in the horizontal direction. The display device 22 displays a slide bar 102, which is a GUI, in the first touch detection area R5. The slide bar 102 has a handle 104 that moves in response to a sliding operation of a user's finger. The GUI is not particularly limited as long as it accepts a sliding operation of the user's finger, and may be a dial.

The display device 22 may be able to switch between displaying and non-displaying the GUI. In this case, when the GUI is displayed, the control circuit 70 sets a first touch detection area R5 that includes the common electrode 34 in the display area of the GUI. When the GUI is hidden, the control circuit 70 cancels the setting of the first touch detection area R5 and starts from the second touch detection area R1 in which the plurality of common electrodes 34 in the screen are evenly divided into four groups. R4 is set, and a touch is detected in a different second touch detection area for each touch detection period.

As in the first embodiment, touch detection is performed in the first touch detection area R5 at a shorter cycle than in each of the second touch detection areas. Therefore, as shown in FIG. 10(c), when the operating position of the handle 104 moves relatively largely during the subframe period Fb, the operating position is detected approximately every 2.1 ms. Therefore, it is easier to detect a plurality of consecutive operation positions on the slide bar 102 than in the control of the first comparative example described above.

Next, the overall operation of the display system 1 with the above configuration will be explained. FIG. 11 is a flowchart showing touch detection processing of the display system 1 according to the third embodiment. The control circuit 70 sets a first touch detection area R5 on the common electrode 34 in the display area of the GUI (S30). The subsequent processes from S10 to S18 are the same as in the first embodiment.

According to this embodiment, it is possible to speed up the response for detecting the operating position of the GUI.

(Fourth embodiment)
The fourth embodiment differs from the third embodiment in that the presence or absence of a touch in the first touch detection area R5 is determined based on the touch detection signal RX in a plurality of touch detection periods. Hereinafter, differences from the third embodiment will be mainly explained.

The touch detection circuit 76 detects a touch in the first touch detection area R5 for each of the plurality of touch detection periods based on the touch detection signal RX received from the common electrode 34 of the first touch detection area R5 during the plurality of touch detection periods. To detect. The plurality of touch detection periods may be, for example, three touch detection periods, and can be appropriately determined by experiment or simulation depending on the number of touch detection periods within the unit frame period Fa.

The touch detection circuit 76 integrates the touch detection signal RX received from each common electrode 34 of the first touch detection region R5 during a plurality of touch detection periods, and calculates an integrated value and a reference value at each pulse timing of the touch drive signal TX. The difference between the two is derived as a detected value, and a touch is detected based on the sum of the plurality of detected values. Specifically, the touch detection circuit 76 compares the sum of detection values based on the touch detection signals RX received from each common electrode 34 of the first touch detection region R5 during a plurality of touch detection periods with a predetermined touch detection threshold. However, when the sum of the detected values is equal to or greater than the touch detection threshold, it is determined that there is a touch at the position of the common electrode 34 . When the touch detection circuit 76 determines that there is a touch, it outputs information on the touch position.

For example, the touch detection circuit 76 determines that there is a touch if the sum of detection values based on the touch detection signals RX during the touch detection periods T1a to T3a is equal to or greater than the touch detection threshold. Thereafter, the presence or absence of a touch is similarly determined every three touch detection periods.

In the second touch detection area, touch detection is performed in the same manner as in the first embodiment. That is, the touch detection circuit 76 detects a touch in the second touch detection area to be detected based on the touch detection signal received from the common electrode 34 in the second touch detection area to be detected during each touch detection period.

That is, the touch detection in the first touch detection area R5 is performed based on the touch detection signal RX of a longer period than the touch detection in the second touch detection area. Therefore, the touch detection sensitivity of the first touch detection area R5 can be made higher than the sensitivity of the second touch detection area. Therefore, even when the GUI is touched with a glove or the like with a relatively small amount of change in capacitance, the touch position can be detected with high sensitivity.

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

Further, although the control device 24 is included in the display module 20 in the first to fourth embodiments, the control device 24 may be included in the host 10. In the first to fourth embodiments, the first drive circuit 72 generates the reference clock signal, but the second drive circuit 74 may generate the reference clock signal. The frame period may include three or more touch detection periods as the number of touch detection areas of the display device 22. In these modified examples, the degree of freedom in the configuration of the display system 1 can be improved.

(Fifth embodiment)
In the fifth embodiment, when a touch is detected in one of a plurality of touch detection areas, the touch is continuously detected in the touch detection area where the touch was detected in a plurality of touch detection periods. The control of the display device 22 by the control circuit 70 and the operation of the display device 22 will be specifically described below, focusing on the differences from the first embodiment. The control circuit 70 alternately displays a partial image on one of the plurality of display areas on the screen and performs partial touch detection on one of the plurality of touch detection areas on the screen, thereby displaying the image and displaying the image. Control touch detection in a time-sharing manner.

FIG. 12 is a diagram illustrating the operation of the display device 22 according to the fifth embodiment. The display device 22 includes four touch detection areas R10, R20, R30, and R40 in which a plurality of common electrodes 34 within the screen are divided into a plurality of groups. Touch detection regions R10, R20, R30, and R40 are lined up in order from left to right in the horizontal direction when viewed from the viewer. A plurality of common electrodes 34 throughout the display device 22 are arranged in each of the touch detection regions R10 to R40. The number of common electrodes 34 arranged in each touch detection area shown in FIG. 12 is an example. The number of touch detection areas is not limited to "4".

The touch detection circuit 76 includes an A/D converter 761 and switches SW1, SW2, SW3, and SW4. Although not shown, each switch has multiple sets of input terminals and output terminals. In FIG. 12, the connection between the common electrode 34 and the signal line 36 is omitted to simplify the drawing.

The plurality of input terminals of the switch SW1 are connected one-to-one to a plurality of common electrodes 34 included in the touch detection region R10 via signal lines 36. A plurality of input terminals of the switch SW2 are connected one-to-one to a plurality of common electrodes 34 included in the touch detection region R20 via a signal line 36. The plurality of input terminals of the switch SW3 are connected one-to-one to a plurality of common electrodes 34 included in the touch detection region R30 via a signal line 36. A plurality of input terminals of the switch SW4 are connected one-to-one to a plurality of common electrodes 34 included in the touch detection region R40 via a signal line 36.

The output terminals of switches SW1 to SW4 are connected to the input port of A/D converter 761. Since the number of input ports of the A/D converter 761 is smaller than the number of common electrodes 34 in the screen, the common electrodes 34 connected to the input ports of the A/D converter 761 are switched by a switch. The number of input ports of the A/D converter 761 is equal to the number of input signals that the A/D converter 761 can process simultaneously, and can also be called the number of input channels.

The control circuit 70 performs different controls until a touch is detected and when a touch is detected.

First, the operation when no touch is detected will be explained. FIG. 13A shows the timing of the unit frame period Fa and the waveform of the touch drive signal TX when no touch is detected on the display device 22 according to the fifth embodiment.

The example shown in FIG. 13A is an example in which one image is displayed in a unit frame period (one frame period) Fa, and touch detection for one screen is executed twice. In this embodiment, since the display device 22 is assumed to display images driven at 60 Hz, the unit frame period Fa is set to approximately 16.7 (=1/60) ms. Since touch detection for one screen is executed twice in the unit frame period Fa, it is executed at a cycle of approximately 8.3 (=1/120) ms.

The unit frame period Fa is divided into two subframe periods Fb. Each subframe period Fb includes four display periods Da and four touch detection periods T1a, T2a, T3a, and T4a. The display period Da and the touch detection period are arranged alternately. In each subframe period Fb, a display period Da, a touch detection period T1a, a display period Da, a touch detection period T2a, a display period Da, a touch detection period T3a, a display period Da, and a touch detection period T4a are arranged in this order. The number of display periods Da and the number of touch detection periods in the unit frame period Fa are not limited to "8".

The display device 22 displays 1/8 of one frame every display period Da. One frame is displayed by eight display periods Da of the unit frame period Fa. Specifically, during the display period Da, the first drive circuit 72 supplies a source signal SS to a plurality of source lines, supplies a gate signal GS to a target gate line, and the second drive circuit 74 supplies a plurality of common source lines with a gate signal GS. A reference voltage VCOM is supplied to the electrode 34. The second drive circuit 74 stops supplying the touch drive signal TX during the display period Da.

The second drive circuit 74 supplies the touch drive signal TX to the plurality of common electrodes 34 in the touch detection regions R10 to R40 during each touch detection period. The second drive circuit 74 stops supplying the reference voltage VCOM during the touch detection period.

When a touch is not detected, the control circuit 70 turns on a different one of the switches SW1 to SW4 for each touch detection period. The touch detection signal RX input to the conductive switch is output to the A/D converter 761. The A/D converter 761 converts the analog touch detection signal RX input via the switch into a digital touch detection signal.

The touch detection circuit 76 detects the touch of an object to the touch detection region R10 during the touch detection period T1a based on the touch detection signals RX received from the plurality of common electrodes 34 in the touch detection region R10. The touch detection circuit 76 detects the touch of an object on the touch detection region R20 during the touch detection period T2a based on the touch detection signals RX received from the plurality of common electrodes 34 in the touch detection region R20.

The touch detection circuit 76 detects the touch of an object on the touch detection region R30 during the touch detection period T3a based on the touch detection signals RX received from the plurality of common electrodes 34 in the touch detection region R30. The touch detection circuit 76 detects the touch of an object on the touch detection region R40 during the touch detection period T4a based on the touch detection signals RX received from the plurality of common electrodes 34 in the touch detection region R40.

In this manner, when a touch is not detected, the touch detection circuit 76 detects a touch in a different touch detection area for each touch detection period in each of a plurality of touch detection periods. In other words, the touch detection circuit 76 sequentially changes the touch detection area to be detected. Touch detection for one screen is executed twice during the eight touch detection periods of the unit frame period Fa. Note that the display device 22 may include the same number of touch detection areas as the number of touch detection periods in the unit frame period Fa, and in this case, touch detection for one screen is performed by a plurality of touch detection periods in the unit frame period Fa. Executed once.

Next, the operation when a touch is detected in one of the plurality of touch detection regions R10 to R40 will be described. FIG. 13B shows the timing of the unit frame period Fa and the waveform of the touch drive signal TX when a touch is detected on the display device 22 according to the fifth embodiment.

When a touch is detected, the control circuit 70 continues to make the switches SW1 to SW4 conductive that were conductive at the time the touch was detected. When a touch is detected, the touch detection circuit 76 continuously detects the touch in a plurality of touch detection periods in the touch detection area where the touch was detected.

When the touch detection circuit 76 continuously detects a touch in the touch detection area where the touch is detected, the touch detection circuit 76 detects the touch in each of a plurality of touch detection periods, and outputs touch position information each time a touch is detected. do. That is, information on the touch position is output for each touch detection period.

In the examples shown in FIGS. 12 and 13(b), a touch is detected in the touch detection region R20 during the touch detection period T2a. Therefore, the touch detection circuit 76 continuously detects touches in the touch detection region R20 during touch detection periods T3a, T4a, T1a, T2a, and T4a following the touch detection period T2a.

When the touch detection circuit 76 continuously detects a touch in the touch detection area where the touch was detected, when the touch detection is interrupted, the touch detection circuit 76 returns to the operation when no touch is detected, and performs different touch detection for each touch detection period. Detect a touch in the area. As a result, if the touch is interrupted, the touch can be detected again on the entire screen.

A second comparative example will now be described. The second comparative example differs from the present embodiment in that a touch is detected in a different touch detection area for each touch detection period, as shown in FIG. 13A, regardless of whether a touch is detected. Touch detection for a certain touch detection area is performed every 8.3 ms of the subframe period Fb. Therefore, for example, if a touched object slides or leaves the screen within 8.3 ms after a touch is detected in the touch detection area R20 during the touch detection period T2a, this will not be detected immediately. In the next touch detection period T2a, the position of the slide destination of the object or the interruption of the touch is detected.

In contrast to this second comparative example, this embodiment continuously detects touches in the touch detection area where the touch was detected as described above, so the response of touch detection is faster than that of the second comparative example. can be converted into In the example of FIG. 13(b), touch detection in the touch detection area R20 where a touch has been detected is performed at a cycle of about 2.1 ms. Therefore, it is possible to detect that the touched object slides or leaves the screen at an earlier timing than in the second comparative example.

Next, the overall operation of the display system 1 with the above configuration will be explained. FIG. 14 is a flowchart showing touch detection processing of the display system 1 according to the fifth embodiment. The touch detection circuit 76 detects a touch in a different touch detection area for each touch detection period (S110), and if a touch is not detected (N in S112), the process returns to S112. If a touch is detected (Y in S112), the touch detection circuit 76 detects a touch in the touch detection area where the touch was detected (S114), and if a touch is detected (Y in S116), the control circuit 76 calculates the coordinates (S118) and returns to S114. If no touch is detected in S116 (N in S116), the process returns to S110.

According to this embodiment, since a touch is detected continuously in a plurality of touch detection periods in a touch detection area where a touch is detected, the response of touch detection can be sped up. Furthermore, it is possible to increase the frequency of outputting touch position information.

(Another detection example in the fifth embodiment)
In the second comparative example, there is a possibility that a touch has been erroneously detected even if the object has not been touched due to noise or the like. To deal with this, a third comparative example is also known in which touch position information is output only when a touch is continuously detected at the same position during a plurality of touch detection periods. In this case, even if a touch is detected only once due to noise or the like, information on the touch position is not output, so that erroneous detection can be suppressed. However, when outputting touch position information when two consecutive touches are detected, for example, the time required to output the touch position information is twice that of the second comparative example, resulting in a slow response.

Therefore, in the fifth embodiment, the touch detection circuit 76 detects a touch in each of a plurality of touch detection periods in a touch detection area where a touch is detected, and detects a touch continuously a predetermined number of times. In this case, information on the touch position may be output. The predetermined number of times is a plurality of times, and can be appropriately determined by experiment or simulation depending on the number of touch detection periods within the unit frame period Fa. Thereby, while suppressing false detections, the response can be made faster than in the third comparative example.

(Sixth embodiment)
The sixth embodiment differs from the fifth embodiment in that a touch is detected based on the sum of detection values of a plurality of touch detection periods in a touch detection area where a touch is detected. Hereinafter, differences from the fifth embodiment will be mainly explained.

Similarly to the fifth embodiment, when a touch is not detected, the touch detection circuit 76 compares the sum of detection values based on the touch detection signal RX received from each common electrode 34 with the first touch detection threshold. , when the sum of the detected values is greater than or equal to the first touch detection threshold, it is determined that there is a touch at the position of the common electrode 34. The first touch detection threshold is set to be smaller than the sum of the detected values obtained in that case, so that when a glove, etc., whose capacitance changes less than a finger, is touched, it is determined that there is a touch. Ru. At this point, the touch detection circuit 76 does not output information on the touch position because there is a possibility that it will be erroneously determined that there is a touch due to the influence of noise. Therefore, output of incorrect touch positions due to noise can be suppressed.

When continuously detecting a touch in a touch detection area where a touch has been detected, the touch detection circuit 76 detects a touch for each of the plurality of touch detection periods based on the touch detection signal RX received during the plurality of touch detection periods. To detect. The plurality of touch detection periods may be, for example, three touch detection periods, and can be appropriately determined by experiment or simulation depending on the number of touch detection periods within the unit frame period Fa.

In this case, the touch detection circuit 76 integrates the touch detection signal RX received from each common electrode 34 during a plurality of touch detection periods, and detects the difference between the integrated value and the reference value at each pulse timing of the touch drive signal TX. A touch is detected based on the sum of multiple detected values. Specifically, the touch detection circuit 76 compares the sum of detection values based on the touch detection signals RX received from each common electrode 34 during a plurality of touch detection periods with a predetermined second touch detection threshold, and determines the detection value. When the sum is equal to or greater than the second touch detection threshold, it is determined that there is a touch at the position of the common electrode 34 . When the touch detection circuit 76 determines that there is a touch, it outputs information on the touch position. The second touch detection threshold is greater than the first touch detection threshold.

In the example of FIG. 13(b), when a touch is detected in the touch detection period T2a, the touch detection circuit 76 determines that the sum of the detection values based on the touch detection signals RX of the three touch detection periods T2a to T4a is the second touch. If it is greater than or equal to the detection threshold, it is determined that there is a touch. Thereafter, the presence or absence of a touch is similarly determined every three touch detection periods until the touch detection is interrupted.

FIG. 15 is a flowchart showing touch detection processing of the display system 1 according to the sixth embodiment. The processing in S110 and S112 is the same as in the fifth embodiment. If a touch is detected in S112 (Y in S112), the touch detection circuit 76 receives the touch detection signal RX from the touch detection area where the touch was detected during the touch detection period (S130), and performs the next touch detection. In the period, the touch detection signal RX is received from the touch detection area where the touch was detected (S132), and in the next touch detection period, the touch detection signal RX is received from the touch detection area where the touch was detected (S134). ). If a touch is detected based on these touch detection signals RX (Y in S136), the control circuit 70 calculates coordinates based on the touch detection signals RX of the three touch detection periods (S138), and returns to S130. . If no touch is detected in S136 (N in S136), the process returns to S110.

In the second comparative example described above, similarly to the fifth embodiment, the presence or absence of a touch is determined based on the sum of detection values equal to the number of pulses of the touch drive signal TX within one touch detection period. is determined. Therefore, as the number of pulses of the touch drive signal TX within one touch detection period is increased, the sum of the detected values can be made larger, and the touch sensitivity can be improved. However, since there is a limit to the length of one touch detection period, it is difficult to increase the number of pulses of the touch drive signal TX in the second comparative example.

In contrast to the second comparative example, in this embodiment, the sum of detected values can be made large without increasing the number of pulses of the touch drive signal TX within one touch detection period, and the sensitivity of touch detection It is possible to speed up the response by improving the In the display device 22 for in-vehicle use, a resin cover is often used instead of glass as a protective layer on the front side of the display device 22 from the viewpoint of safety and the increasing demand for curved displays. In the case of a resin cover, the dielectric constant is lower than that of glass, which leads to a decrease in touch sensitivity. In this embodiment, sensitivity can be improved even in the case of a resin cover.

Furthermore, in the second comparative example, the radiation caused by the touch drive signal TX can be reduced by reducing the amplitude of the touch drive signal TX, but the sensitivity is reduced. In contrast to the second comparative example, in this embodiment, the amplitude of the touch drive signal TX can be reduced while maintaining the detection sensitivity. Therefore, radiation can be reduced while suppressing a decrease in sensitivity.

(Seventh embodiment)
In the seventh embodiment, the touch detection method for continuously detecting touches in the touch detection area where the touch is detected is switched according to the sum of detection values when the touch is detected. This is different from the embodiment of . Hereinafter, differences from the fifth embodiment will be mainly explained.

Similarly to the fifth embodiment, when a touch is not detected, the touch detection circuit 76 compares the sum of detection values based on the touch detection signal RX received from each common electrode 34 with the first touch detection threshold. , when the sum of the detected values is greater than or equal to the first touch detection threshold, it is determined that there is a touch at the position of the common electrode 34.

When a touch is detected, the touch detection circuit 76 detects the touch in each of the plurality of touch detection periods if the sum of the detection values of the common electrode 34 where the touch was detected is equal to or greater than the determination threshold, and the touch is detected. Outputs touch position information each time the button is touched. That is, the touch detection circuit 76 executes the touch detection process of the fifth embodiment. The sum total of the detection values of the common electrode 34 where a touch was detected corresponds to a value related to the difference value between the capacitance of the common electrode 34 where a touch was detected and the reference capacitance.

If the sum of the detection values is smaller than the determination threshold, the touch detection circuit 76 detects a touch for each of the plurality of touch detection periods based on the touch detection signal RX received during the plurality of touch detection periods. In other words, the touch detection circuit 76 executes the touch detection process of the sixth embodiment. As described above, the touch detection circuit 76 compares the sum of detection values based on the touch detection signals RX received from each common electrode 34 during a plurality of touch detection periods with the second touch detection threshold, and determines the sum of the detection values. is greater than or equal to the second touch detection threshold, it is determined that there is a touch at the position of the common electrode 34.

The determination threshold is set to be smaller than the sum of detected values obtained when a finger or the like with a relatively large amount of change in capacitance touches. The determination threshold is greater than the first touch detection threshold.

FIG. 16 is a flowchart showing touch detection processing of the display system 1 according to the seventh embodiment. If a touch is detected in S112 (Y in S112), and if the sum of the detection values of the common electrodes 34 where a touch was detected is equal to or greater than the determination threshold (Y in S140), the process moves to S114. The processing from S114 to S118 is the same as in the fifth embodiment. If the sum of the detection values of the common electrode 34 where a touch was detected is less than the determination threshold (N in S140), the process moves to S130. The processing from S130 to S138 is the same as in the sixth embodiment.

According to this embodiment, when a finger or the like having a relatively large amount of change in capacitance is touched, the touch is detected in each of a plurality of touch detection periods, so that the touch detection response can be sped up. Furthermore, when a glove or the like with a relatively small amount of change in capacitance is touched, the touch is detected every multiple touch detection periods, so detection sensitivity can be improved. Therefore, touch detection suitable for the touched object can be performed.

The present disclosure has been described above based on the embodiments. Those skilled in the art will understand that this embodiment is merely an example, and that various modifications can be made to the combinations of these components or processing processes, and that such modifications are also within the scope of the present disclosure. By the way.

For example, in the seventh embodiment, if the sum of the detection values of the common electrode 34 where a touch was detected is smaller than the determination threshold, processing of another detection example of the fifth embodiment may be executed. In this case, the degree of freedom in configuring the display system 1 can be improved.

Further, although the control device 24 is included in the display module 20 in the fifth to seventh embodiments, the control device 24 may be included in the host 10. In the fifth to seventh embodiments, the first drive circuit 72 generates the reference clock signal, but the second drive circuit 74 may generate the reference clock signal. The frame period may include three or more touch detection periods as the number of touch detection areas of the display device 22. In these modified examples, the degree of freedom in the configuration of the display system 1 can be improved.

The display device 22 may have the configuration described below, for example. FIG. 17 is a longitudinal cross-sectional view of the display device 22 of FIG. The display device 22 includes a backlight unit 40, a lower polarizing plate 42, a thin film transistor substrate (hereinafter referred to as a TFT substrate) 44, a liquid crystal layer 52, a color filter substrate 54, and an upper polarizing plate, which are arranged one on top of the other in the thickness direction. It includes a plate 56, a bonding layer 58, and a protective layer 60.

In the following description, in the thickness direction of the display device 22, the side where the protective layer 60 is located with respect to the TFT substrate 44 will be referred to as the front side, and the opposite side will be referred to as the back side.

The display device 22 uses the light emitted from the backlight unit 40 to emit image light toward the front side, that is, toward the viewer.

The TFT substrate 44 includes a glass substrate 46 , a plurality of gate electrodes 48 arranged on the front side of the glass substrate 46 , a plurality of source electrodes 50 , and a plurality of common electrodes 34 . Although not shown, the TFT substrate 44 includes the plurality of gate lines G1, G2, ..., the plurality of source lines S1, S2, ..., the plurality of pixel electrodes 32, and the plurality of pixel switching elements 30 in FIG. It also has The liquid crystal layer 52 disposed on the front side of the TFT substrate 44 is controlled by a lateral electric field generated between the pixel electrode 32 and the common electrode 34.

The bonding layer 58 has translucency and bonds the upper polarizing plate 56 and the protective layer 60. The bonding layer 58 is, for example, a liquid transparent resin such as OCR (Optically Clear Resin) or a cured transparent adhesive sheet such as OCA (Optically Clear Adhesive).

The protective layer 60 is a transparent layer for protecting the display device 22, and is made of a glass substrate, a plastic substrate, or the like. The protective layer 60 is also called a cover lens or the like.

A display system according to one aspect of the present disclosure is as follows.
a display device having a plurality of common electrodes shared for image display and touch detection;
a drive circuit that supplies a touch drive signal to each of the plurality of common electrodes;
a touch detection circuit that detects a touch of an object to the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which the touch detection circuit detects a touch are arranged alternately,
The display device includes a first touch detection area and a plurality of second touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The touch detection circuit detects a touch in the same first touch detection area and a different second touch detection area for each touch detection period in a plurality of touch detection periods.
According to this aspect, the touch detection response of the first touch detection area can be made faster than that of the second touch detection area.

In the display system according to one aspect of the present disclosure, for example,
It may also include a control circuit that, when a touch is detected, sets the first touch detection area including the common electrode at the position where the touch is detected.
In this case, it is possible to speed up the touch detection response at the position where the touch is detected.

In the display system according to one aspect of the present disclosure, for example,
When the control circuit sets the first touch detection area including a common electrode at a position where a touch is detected, when touch detection in the first touch detection area is interrupted, the control circuit changes the setting of the first touch detection area. Alternatively, a touch may be detected in a different second touch detection area for each touch detection period.
In this case, if touch detection is interrupted, the number of touch detection signals processed by the touch detection circuit in one touch detection period can be reduced.

In the display system according to one aspect of the present disclosure, for example,
When the control circuit sets the first touch detection area including a common electrode at a position where a touch is detected, the control circuit divides the common electrodes other than the first touch detection area into a plurality of groups and divides the common electrodes into the plurality of second touch detection areas. The touch detection area may also be reset.
In this case, the number of common electrodes in each of the second touch detection areas can be made close to equal.

In the display system according to one aspect of the present disclosure, for example,
comprising a rotatable dial arranged in the first touch detection area on the display surface of the display device,
The touch detection circuit may detect a rotational operation position of the dial as a touch position.
In this case, the response for detecting the rotational operation position of the dial can be made faster.

In the display system according to one aspect of the present disclosure, for example,
The display device may display a GUI (Graphical User Interface) in the first touch detection area.
In this case, the response time for detecting the operating position of the GUI can be sped up.

In the display system according to one aspect of the present disclosure, for example,
The touch detection circuit detects a touch in the first touch detection area for each of the plurality of touch detection periods based on the touch detection signal received from the common electrode of the first touch detection area during the plurality of touch detection periods. It's fine if you do.
In this case, the touch detection sensitivity of the first touch detection area can be made higher than that of the second touch detection area.

A control device according to one aspect of the present disclosure includes:
A control device that controls a display device having a plurality of common electrodes shared for image display and touch detection,
a drive circuit that supplies a touch drive signal to each of the plurality of common electrodes;
a touch detection circuit that detects a touch of an object to the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which the touch detection circuit detects a touch are arranged alternately,
The display device includes a first touch detection area and a plurality of second touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The touch detection circuit detects a touch in the same first touch detection area and a different second touch detection area for each touch detection period in a plurality of touch detection periods.
According to this aspect, the touch detection response of the first touch detection area can be made faster than that of the second touch detection area.

A control method according to one aspect of the present disclosure includes:
A control method in a display device having a plurality of common electrodes shared for image display and touch detection, the method comprising:
providing a touch drive signal to each of the plurality of common electrodes;
detecting a touch of an object on the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
Display periods in which the display device displays an image and touch detection periods in which a touch is detected are arranged alternately in a unit frame period in the display device,
The display device includes a first touch detection area and a plurality of second touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
In the step of detecting a touch, a touch is detected in the same first touch detection area and a different second touch detection area for each touch detection period in a plurality of touch detection periods.
According to this aspect, the touch detection response of the first touch detection area can be made faster than that of the second touch detection area.

A display system according to one aspect of the present disclosure is as follows.
a display device having a plurality of common electrodes shared for image display and touch detection;
a drive circuit that supplies a touch drive signal to each of the plurality of common electrodes;
a touch detection circuit that detects a touch of an object to the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which the touch detection circuit detects a touch are arranged alternately,
The display device includes a plurality of touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The touch detection circuit detects a touch in a different touch detection area for each touch detection period when a touch is not detected, and determines that a touch has been detected when a touch is detected in one of the plurality of touch detection areas. A touch is continuously detected in a touch detection area in a plurality of touch detection periods.
According to this aspect, the response of touch detection can be sped up.

In the display system according to one aspect of the present disclosure, for example,
When the touch detection circuit continuously detects touches in the touch detection area where the touch was detected, the touch detection circuit may detect the touch in each of a plurality of touch detection periods.
In this case, the touch detection response can be sped up.

In the display system according to one aspect of the present disclosure, for example,
The touch detection circuit may output touch position information each time a touch is detected.
In this case, the frequency of outputting touch position information can be increased.

In the display system according to one aspect of the present disclosure, for example,
The touch detection circuit may output touch position information when a touch is detected a plurality of times in succession.
In this case, false detection can be suppressed.

In the display system according to one aspect of the present disclosure, for example,
When the touch detection circuit continuously detects a touch in the touch detection area where the touch is detected, the touch detection circuit detects the touch for each of the plurality of touch detection periods based on the touch detection signal received during the plurality of touch detection periods. It's fine if you do.
In this case, since a touch is detected based on a touch detection signal of a longer period, detection sensitivity can be improved. Furthermore, the amplitude of the touch drive signal can be reduced while maintaining detection sensitivity. Therefore, radiation can be reduced.

In the display system according to one aspect of the present disclosure, for example,
When the touch detection circuit continuously detects a touch in the touch detection area where the touch is detected, the touch detection circuit determines the capacitance of the common electrode and the reference capacitance based on the touch detection signals received during a plurality of touch detection periods. It is also possible to derive a plurality of detection values each representing a difference value between the two and detect a touch based on the sum of the plurality of detection values.
In this case, detection sensitivity can be improved.

In the display system according to one aspect of the present disclosure, for example,
When a touch is detected in one of the plurality of touch detection areas, the touch detection circuit (1) determines a value related to a difference value between the capacitance of the common electrode where the touch was detected and a reference capacitance; If it is equal to or greater than the threshold, a touch is detected in each of the plurality of touch detection periods, and (2) if the value related to the difference value is smaller than the determination threshold, based on the touch detection signal received in the plurality of touch detection periods, A touch may be detected for each of the plurality of touch detection periods.
In this case, touch detection suitable for the touched object can be performed.

In the display system according to one aspect of the present disclosure, for example,
When the touch detection circuit continuously detects a touch in the touch detection area where the touch was detected, when the touch detection is interrupted, the touch detection circuit may detect the touch in a different touch detection area for each touch detection period.
In this case, if the touch is interrupted, the touch can be detected on the entire screen.

A control device according to one aspect of the present disclosure includes:
A control device that controls a display device having a plurality of common electrodes shared for image display and touch detection,
a drive circuit that supplies a touch drive signal to each of the plurality of common electrodes;
a touch detection circuit that detects a touch of an object to the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
In a unit frame period of the display device, a display period in which the display device displays an image and a touch detection period in which the touch detection circuit detects a touch are arranged alternately,
The display device includes a plurality of touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The touch detection circuit detects a touch in a different touch detection area for each touch detection period when a touch is not detected, and determines that a touch has been detected when a touch is detected in one of the plurality of touch detection areas. A touch is continuously detected in a touch detection area in a plurality of touch detection periods.
According to this aspect, the response of touch detection can be sped up.

A control method according to one aspect of the present disclosure includes:
A control method in a display device having a plurality of common electrodes shared for image display and touch detection, the method comprising:
providing a touch drive signal to each of the plurality of common electrodes;
detecting a touch of an object on the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
Display periods in which the display device displays an image and touch detection periods in which a touch is detected are arranged alternately in a unit frame period in the display device,
The display device includes a plurality of touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
In the step of detecting a touch, if a touch is not detected, a touch is detected in a different touch detection area for each touch detection period, and if a touch is detected in one of the plurality of touch detection areas, a touch is detected. A touch is detected continuously in a plurality of touch detection periods in the touch detection area.
According to this aspect, the response of touch detection can be sped up.

A display device according to one aspect of the present disclosure includes:
A display device in a display system according to one aspect of the present disclosure, comprising:
It includes a plurality of common electrodes that are shared for image display and touch detection.
According to this aspect, a display device used in a display system can be provided.

DESCRIPTION OF SYMBOLS 1... Display system, 12... Control device, 22... Display device, 24... Control device, 34... Common electrode, 70... Control circuit, 76... Touch detection circuit, 100... Dial, 102... Slide bar.

Claims (20)

a display device having a plurality of common electrodes shared for image display and touch detection;
a drive circuit that supplies a touch drive signal to each of the plurality of common electrodes;
a touch detection circuit that detects a touch of an object to the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
A plurality of display periods in which the display device displays an image and a plurality of touch detection periods in which the touch detection circuit detects a touch are arranged alternately in a unit frame period in the display device,
The display device includes a first touch detection area and a plurality of second touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The plurality of touch detection periods include a first touch detection period and a second touch detection period,
The plurality of second touch detection areas include a third touch detection area and a fourth touch detection area different from the third touch detection area,
In the first touch detection period , the touch detection circuit detects a touch in the first touch detection area and the third touch detection area , does not detect a touch in the fourth touch detection area, and detects a touch in the second touch detection area. A display system characterized in that during a touch detection period, a touch is detected in the first touch detection area and the fourth touch detection area, and a touch is not detected in the third touch detection area. The display system according to claim 1, further comprising a control circuit that, when a touch is detected, sets the first touch detection area including a common electrode at a position where the touch is detected. When the control circuit sets the first touch detection area including a common electrode at a position where a touch is detected, when touch detection in the first touch detection area is interrupted, the control circuit changes the setting of the first touch detection area. 3. The display system according to claim 2, wherein the display system detects a touch in a different second touch detection area for each touch detection period. When the control circuit sets the first touch detection area including a common electrode at a position where a touch is detected, the control circuit divides the common electrodes other than the first touch detection area into a plurality of groups and divides the common electrodes into the plurality of second touch detection areas. 4. The display system according to claim 2, further comprising resetting a touch detection area. comprising a rotatable dial arranged in the first touch detection area on the display surface of the display device,
The display system according to claim 1, wherein the touch detection circuit detects a rotational operation position of the dial as a touch position. The display system according to claim 1, wherein the display device displays a GUI (Graphical User Interface) in the first touch detection area. The touch detection circuit detects a touch in the first touch detection area for each of the plurality of touch detection periods based on the touch detection signal received from the common electrode of the first touch detection area during the plurality of touch detection periods. The display system according to any one of claims 1 to 6, characterized in that: A control device that controls a display device having a plurality of common electrodes shared for image display and touch detection,
a drive circuit that supplies a touch drive signal to each of the plurality of common electrodes;
a touch detection circuit that detects a touch of an object to the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
A plurality of display periods in which the display device displays an image and a plurality of touch detection periods in which the touch detection circuit detects a touch are arranged alternately in a unit frame period in the display device,
The display device includes a first touch detection area and a plurality of second touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The plurality of touch detection periods include a first touch detection period and a second touch detection period,
The plurality of second touch detection areas include a third touch detection area and a fourth touch detection area different from the third touch detection area,
In the first touch detection period , the touch detection circuit detects a touch in the first touch detection area and the third touch detection area , does not detect a touch in the fourth touch detection area, and detects a touch in the second touch detection area. A control device characterized in that during a touch detection period, a touch is detected in the first touch detection area and the fourth touch detection area, and a touch is not detected in the third touch detection area. A control method in a display device having a plurality of common electrodes shared for image display and touch detection, the method comprising:
providing a touch drive signal to each of the plurality of common electrodes;
detecting a touch of an object on the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
A plurality of display periods in which the display device displays an image and a plurality of touch detection periods in which a touch is detected are arranged alternately in a unit frame period in the display device,
The display device includes a first touch detection area and a plurality of second touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The plurality of touch detection periods include a first touch detection period and a second touch detection period,
The plurality of second touch detection areas include a third touch detection area and a fourth touch detection area different from the third touch detection area,
In the step of detecting a touch, in the first touch detection period , a touch is detected in the first touch detection area and the third touch detection area, a touch is not detected in the fourth touch detection area, and the touch is detected in the fourth touch detection area. A control method characterized in that, in a second touch detection period, a touch is detected in the first touch detection area and the fourth touch detection area, and a touch is not detected in the third touch detection area. a display device having a plurality of common electrodes shared for image display and touch detection;
a drive circuit that supplies a touch drive signal to each of the plurality of common electrodes;
a touch detection circuit that detects a touch of an object to the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
A plurality of display periods in which the display device displays an image and a plurality of touch detection periods in which the touch detection circuit detects a touch are arranged alternately in a unit frame period in the display device,
The display device includes a plurality of touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The plurality of touch detection periods include a first touch detection period and a second touch detection period following the first touch detection period,
The plurality of touch detection areas include a first touch detection area and a second touch detection area different from the first touch detection area,
The touch detection circuit detects a touch in the first touch detection area during the first touch detection period,
If a touch is not detected in the first touch detection period , the touch detection circuit detects a touch in the second touch detection area and detects a touch in the first touch detection area in the second touch detection period. Without,
If a touch is detected in the first touch detection period , the touch detection circuit detects a touch in the first touch detection area and detects a touch in the second touch detection area in the second touch detection period. A display system characterized by not detecting touch . When a touch is detected in the first touch detection period , the touch detection circuit continuously detects a touch in the first touch detection area in each of one or more touch detection periods including the second touch detection period. The display system according to claim 10, wherein the display system detects a touch. 12. The display system according to claim 11, wherein the touch detection circuit outputs touch position information every time a touch is detected. 12. The display system according to claim 11, wherein the touch detection circuit outputs touch position information when a touch is detected a plurality of times in succession. When a touch is detected in the first touch detection period , the touch detection circuit detects the first touch in each of the plurality of touch detection periods based on the touch detection signals received in the plurality of touch detection periods. 11. The display system according to claim 10, wherein a touch is detected continuously in the area . When a touch is detected in the first touch detection period , the touch detection circuit calculates the difference between the capacitance of the common electrode and the reference capacitance based on the touch detection signals received in the plurality of touch detection periods. 15. The display system according to claim 14, wherein a plurality of detection values each representing a value are derived, and a touch is detected based on the sum of the plurality of detection values. When a touch is detected in the first touch detection period , the touch detection circuit determines that (1) a value related to a difference value between the capacitance of the common electrode where the touch was detected and a reference capacitance is equal to or greater than a determination threshold; If there is, a touch is detected continuously in the first touch detection area in each of one or more touch detection periods including the second touch detection period, and (2) a value related to the difference value is less than the determination threshold. If the touch detection signal is smaller, the touch detection area is continuously detected in the first touch detection area for each of the plurality of touch detection periods based on the touch detection signal received during the plurality of touch detection periods. The display system described in. When a touch is detected in the first touch detection period, the touch detection circuit detects the first touch detection area in one or more touch detection periods including the second touch detection period until touch detection is interrupted. 17. The display system according to claim 10, wherein the display system detects a touch in a continuous manner , and when the detection of a touch is interrupted, a touch is detected in a different touch detection area for each touch detection period. A control device that controls a display device having a plurality of common electrodes shared for image display and touch detection,
a drive circuit that supplies a touch drive signal to each of the plurality of common electrodes;
a touch detection circuit that detects a touch of an object to the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
A plurality of display periods in which the display device displays an image and a plurality of touch detection periods in which the touch detection circuit detects a touch are arranged alternately in a unit frame period in the display device,
The display device includes a plurality of touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The plurality of touch detection periods include a first touch detection period and a second touch detection period following the first touch detection period,
The plurality of touch detection areas include a first touch detection area and a second touch detection area different from the first touch detection area,
The touch detection circuit detects a touch in the first touch detection area during the first touch detection period,
If a touch is not detected in the first touch detection period , the touch detection circuit detects a touch in the second touch detection area and detects a touch in the first touch detection area in the second touch detection period. Without,
If a touch is detected in the first touch detection period , the touch detection circuit detects a touch in the first touch detection area and detects a touch in the second touch detection area in the second touch detection period. A control device characterized in that it does not detect touch . A control method in a display device having a plurality of common electrodes shared for image display and touch detection, the method comprising:
providing a touch drive signal to each of the plurality of common electrodes;
detecting a touch of an object on the display device based on a touch detection signal received from each of the plurality of common electrodes;
Equipped with
A plurality of display periods in which the display device displays an image and a plurality of touch detection periods in which a touch is detected are arranged alternately in a unit frame period in the display device,
The display device includes a plurality of touch detection areas in which the plurality of common electrodes are divided into a plurality of groups,
The plurality of touch detection periods include a first touch detection period and a second touch detection period following the first touch detection period,
The plurality of touch detection areas include a first touch detection area and a second touch detection area different from the first touch detection area,
In the step of detecting a touch, detecting a touch in the first touch detection area during the first touch detection period;
If a touch is not detected in the first touch detection period , in the step of detecting a touch, a touch is detected in the second touch detection area in the second touch detection period , and a touch is not detected in the first touch detection area. is not detected,
If a touch is detected in the first touch detection period , the step of detecting a touch includes detecting a touch in the first touch detection area in the second touch detection period , and detecting a touch in the second touch detection period. A control method characterized by not detecting touch in the area . A display device in the display system according to claim 1 or 10,
A display device comprising a plurality of common electrodes used for image display and touch detection.

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