Capacitive touch display device and touch sensing method

Abstract

The invention discloses a capacitive touch display device and a touch sensing method. The capacitive touch display device comprises a touch panel, a display panel, a touch sensing control circuit and a time sequence controller, the touch panel comprises a cover plate and a touch electrode layer. A plurality of first electrodes arranged in the first direction and a plurality of second electrodes arranged in the second direction are formed on the touch electrode layer. The touch sensing control circuit is electrically connected with the first electrode and the second electrode. In the touch sensing stage, one of the first electrode and the second electrode serves as a driving electrode, and the other serves as a sensing electrode. The touch sensing control circuit performs synchronous processing on a plurality of driving signals and a synchronous control signal output by the time schedule controller in a touch sensing stage, provides the plurality of driving signals to the plurality of driving electrodes at the same time, and receives sensing capacitance generated by each sensing electrode. In this way, the display panel stops refreshing the display picture in the touch sensing stage. The plurality of driving signals are in-phase signals.

Description

Capacitive touch display device and touch sensing method Technical Field

[0001] The present invention relates to the field of touch display technology, and in particular to a capacitive touch display device and a touch sensing method. Background Art

[0002] A capacitive touch display device includes a display screen. The touch display device includes a cover plate, a touch electrode layer, a first display electrode layer, a dielectric layer, a light-emitting layer, and a second display electrode layer, which are stacked in sequence. The first display electrode layer, the dielectric layer, the light-emitting layer, and the second display electrode layer constitute a display structure. Because the first display electrode layer is relatively close to the touch electrode layer, applying a driving voltage to the touch electrode layer for touch sensing generates a large capacitance between the touch electrode in the touch electrode layer and the first display electrode in the first display electrode layer, interfering with the first display electrode. This in turn causes interference with the display structure's display image, resulting in flickering or streaking, which negatively impacts the display structure.

[0003] Summary of the Invention

[0004] The main purpose of the present invention is to provide a capacitive touch display device and a touch sensing method, aiming to solve the problem in the prior art of how to prevent the touch electrodes from negatively affecting the display structure when loading a driving signal.

[0005] A capacitive touch display device comprises a touch panel, a display panel, a touch sensing control circuit and a timing controller; the touch panel is stacked with a cover plate and a touch electrode layer in sequence from top to bottom; the touch electrode layer is patterned to form a plurality of first electrodes arranged along a first direction and a plurality of second electrodes arranged along a second direction; the touch sensing control circuit is electrically connected to the first electrode and the second electrode; in a touch sensing stage, one of the first electrode and the second electrode serves as a driving electrode and the other serves as a sensing electrode; the touch sensing control circuit is used to provide a driving signal to the plurality of driving electrodes in the touch sensing stage and receive a sensing capacitance generated by each of the sensing electrodes; the timing controller The sequence controller outputs a synchronization control signal, wherein the synchronization control signal includes a display synchronization signal and a line synchronization signal. The display panel completes scanning of one line of image within one cycle of the line synchronization signal, and completes scanning of images of all lines of the display panel once within one cycle of the display synchronization signal. The touch sensing control circuit is further used to synchronize the drive signal with the synchronization control signal so that the display panel stops refreshing the display screen during the touch sensing phase, and the touch sensing control circuit simultaneously provides multiple drive signals to the drive electrodes. The multiple drive signals are in-phase signals, which are pulse signals with the same frequency, phase and amplitude.

[0006] In addition, to achieve the above-mentioned objectives, the present invention further provides a touch sensing method, which is applied to a capacitive touch display device; the capacitive touch display device includes a touch panel, a display panel, a touch sensing control circuit, and a timing controller; the touch panel includes a cover plate and a touch electrode layer stacked sequentially from top to bottom; the touch electrode layer is patterned to form a plurality of first electrodes arranged along a first direction and a plurality of second electrodes arranged along a second direction; the touch sensing control circuit is electrically connected to the first electrodes and the second electrodes; in a touch sensing phase, one of the first electrode and the second electrode serves as a drive electrode and the other serves as a sensing electrode; the touch sensing control circuit is configured to provide a drive signal to the plurality of drive electrodes during the touch sensing phase; the touch sensing method includes:

[0007] Acquire a synchronization control signal from the timing controller; the synchronization control signal includes a display synchronization signal and a line synchronization signal, wherein the display panel completes scanning of one line of image within one cycle of the line synchronization signal, and completes scanning of all lines of image on the display panel once within one cycle of the display synchronization signal;

[0008] Synchronously processing the driving signal and the synchronization control signal so that the display panel stops refreshing a display image during the touch sensing phase;

[0009] Simultaneously providing a plurality of the driving signals to the driving electrodes, receiving the sensing capacitance of the sensing electrodes, and converting the sensing capacitance into a digital signal; wherein the driving signal is a periodic in-phase signal, and the in-phase signal is a pulse signal having the same frequency, phase, and amplitude;

[0010] The digital signal is analyzed to obtain a touch position of the touch object on the capacitive touch display device.

[0011] The above-mentioned capacitive touch display device and touch sensing method synchronize the driving signal with the synchronization control signal output by the timing controller, so that the display image of the display panel remains unchanged during the touch sensing stage, thereby reducing the signal interference between the touch electrode layer and the display panel during the touch sensing stage, thereby avoiding flickering or stripes on the display image of the capacitive touch display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0013] FIG1 is a schematic diagram of a capacitive touch display device according to a preferred embodiment of the present invention.

[0014] FIG. 2 is a schematic diagram of a module of the capacitive touch display device shown in FIG. 1 .

[0015] FIG3 is a schematic cross-sectional view of the capacitive touch display device shown in FIG1 along the III-III direction.

[0016] FIG. 4 is a schematic diagram of digital signals corresponding to a plurality of sensing electrodes in a no-touch state in FIG. 2 .

[0017] FIG. 5 is a schematic diagram of digital signals corresponding to a plurality of sensing electrodes in a touch-sensitive state in FIG. 2 .

[0018] FIG. 6 is a waveform diagram of the display synchronization signal and the plurality of driving signals shown in FIG. 2 .

[0019] FIG. 7 is a waveform diagram of the horizontal synchronization signal and a plurality of the driving signals in FIG. 2 .

[0020] FIG8 is a waveform diagram of the display synchronization signal, the row synchronization signal, and a plurality of the driving signals in FIG2 .

[0021] FIG9 is a flow chart of a touch sensing method according to a preferred embodiment of the present invention.

[0022] FIG10 is a detailed flowchart of S92 in FIG9 .

[0023] Description of Main Component Symbols Capacitive Touch Display Device 1 Touch Panel 10 Display Panel 20 Cover Plate 11 Touch Electrode Layer 12 First Display Electrode Layer 21 Light Emitting Layer 22 Second Display Electrode Layer 23 Dielectric Layer 24 First Electrodes 121_1 to 121_m Second Electrodes 123_1 to 123_n Driving Electrodes TX_1 to TX_5 Sensing Electrodes RX_1 to RX_10 Touch Display Area 101 Non-Display Area 103 Touch Sensing Control Circuit 30 Touch Sensing Line 301 Synchronous Signal Processing Module 31 Control Module 32 First Multiplexing Module 33 Second Multiplexing Module 34 Touch Driving Module 35 Touch Sensing Module 36 Digital Signal Processing Module 37 Timing Controller 40 Touch Sensing Phase Ts Predetermined Time Period T Steps S91-S94

[0024] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0026] The terms "first," "second," and "third" in the specification of the present invention and the accompanying drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "include" and any variations thereof are intended to cover non-exclusive inclusions.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] Specific embodiments of the capacitive touch display device and the touch sensing method of the present invention are described below with reference to the accompanying drawings.

[0029] Please refer to Figure 1, which is a schematic diagram of a capacitive touch display device 1. The capacitive touch display device 1 can be a portable device such as a personal computer, tablet computer, smartphone, personal digital assistant (PDA), game console, interactive Internet Protocol Television (IPTV), smart wearable device, navigation device, etc., or a fixed device such as a desktop computer, server, digital television, etc. The capacitive touch display device 1 can further include a combination of one or more of fingerprint recognition, display, and camera functions.

[0030] The capacitive touch display device 1 includes a touch panel 10 and a display panel 20 .

[0031] The touch panel 10 is used to sense a user's touch operation and includes a cover plate 11 and a touch electrode layer 12 stacked sequentially from top to bottom.

[0032] The cover plate 11 may be a glass substrate or other transparent substrate with high strength and hardness. In at least one embodiment of the present invention, the cover plate 11 may be made of a material such as polycarbonate (PC), polyester (PET), polymethylmethacrylate (PMMA), cycloolefin copolymer (COC), or polyether sulfone (PES).

[0033] Please also refer to Figure 2, which is a schematic diagram of the touch electrode layer 12 module. The touch electrode layer 12 is made of a conductive material and can be patterned to form a plurality of first electrodes 121_1 to 121_m and a plurality of second electrodes 123_1 to 123_n. m and n are positive integers and can be the same or different. The plurality of first electrodes 121_1 to 121_m extend along a first direction X and are arranged parallel to each other. The plurality of second electrodes 123_1 to 123_n extend along a second direction Y and are arranged parallel to each other. In at least one embodiment of the present invention, the first direction X is perpendicular to the second direction Y. In other embodiments, the first direction X and the second direction Y can intersect at other angles. At any time during the touch sensing stage Ts (as shown in Figures 4-6), one of the first electrodes 121_1 to 121_m and the second electrodes 123_1 to 123_n serves as a drive electrode, and the other serves as a sensing electrode. When a ground conductor (e.g., a finger or stylus) is placed on the cover plate 11, an inductive capacitance is generated between the sensing electrode and the ground conductor. In at least one embodiment of the present invention, the touch electrode layer 12 can be a single-layer conductive structure to form a self-capacitive touch sensing structure. In other embodiments, the touch electrode layer 12 can also be a multi-layer conductive structure to form a mutual-capacitive touch sensing structure.

[0034] Please also refer to Figure 3, which is a schematic cross-sectional view of the display panel 20 along the III-III direction. The display panel 20 is located below the touch panel 10 and is used to display images. The display panel 20 includes a first display electrode layer 21, a light-emitting layer 22, a second display electrode layer 23, and a dielectric layer 24. In at least one embodiment of the present invention, the display panel 20 is a flexible active matrix organic light emitting diode (AMOLED) display panel. In other embodiments, the display panel 20 can also be other types of display panels, such as a liquid crystal display panel, a field emission display panel, a plasma display panel, and an electrophoretic display panel.

[0035] The first display electrode layer 21 is arranged on a side of the dielectric layer 24 away from the touch electrode layer 12. The first display electrode layer 21 can be patterned to form a plurality of first display electrodes (e.g., cathodes). The light-emitting layer 22 is arranged between the first display electrode layer 21 and the second display electrode layer 23, and is located on a side of the first display electrode layer 21 away from the dielectric layer 24. The light-emitting layer 22 is used to emit light when a driving voltage is applied to the first display electrode layer 21 and the second display electrode layer 23. In at least one embodiment of the present invention, the light-emitting layer 22 may further include a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting layer (EML), and an electron transport layer (ETL). The second display electrode layer 23 is arranged on a side of the light-emitting layer 22 away from the first display electrode layer 21. The second display electrode layer 23 can be patterned to form a plurality of second display electrodes (e.g., anodes).

[0036] 1 and 2 , the capacitive touch display device 1 defines a touch display area 101 and a non-display area 103 surrounding the touch display area 101. A plurality of first electrodes 121_1 to 121_m and a plurality of second electrodes 123_1 to 123_n are located within the touch display area 101 and may extend into the non-display area 103.

[0037] Referring to Figure 2, the capacitive touch display device 1 also includes a touch sensing control circuit 30 and a timing controller 40. The touch sensing control circuit 30 can be arranged in the non-display area 103 and electrically connected to the plurality of first electrodes 121_1~121_m and the plurality of second electrodes 123_1~123_n through the touch sensing line 301. The touch sensing control circuit 30 is used to provide a driving signal to the plurality of driving electrodes in the touch sensing phase Ts (as shown in Figures 6 to 8) and receive the sensing capacitance generated by each of the sensing electrodes. Furthermore, the touch sensing control circuit 30 performs synchronization processing with the driving signal according to the synchronization control signal output by the timing controller 40. After the synchronization processing, the display panel 20 stops refreshing the display screen in one of the touch sensing phases Ts.

[0038] The touch sensing control circuit 30 includes a synchronous signal processing module 31 , a control module 32 , a first multiplex selection module 33 , a second multiplex selection module 34 , a touch driving module 35 , a touch sensing module 36 and a digital signal processing module 37 .

[0039] The synchronization signal processing module 31 is electrically connected to the timing controller 40 and the control module 32. The synchronization signal processing module 31 identifies the start and end times of the synchronization control signal output by the timing controller 40 within a cycle and provides them to the control module 32. The synchronization control signal is a periodic pulse signal, wherein the start time is the time when the rising edge of the synchronization control signal is generated within a cycle, and the end time is the time when the falling edge of the synchronization control signal is generated within the same cycle. In at least one embodiment of the present invention, the synchronization control signal may include a display synchronization signal Vsync and a row synchronization signal Hsync. Within one cycle of the display synchronization signal Vsync, the display panel 20 completes the scanning of one frame of image; within one cycle of the row synchronization signal Hsync, the display panel 20 completes the scanning of one row of image. Within one cycle of the display synchronization signal Vsync, the number of cycles of the row synchronization signal Hsync is consistent with the number of rows of the display panel 20. That is, within one cycle of the display synchronization signal Vsync, the image scanning of all rows of the display panel 20 is completed. The synchronization signal processing module 31 identifies the start time and the end time of one of the display synchronization signal Vsync and the horizontal synchronization signal Hsync.

[0040] The control module 32 is electrically connected to the synchronization signal processing module 31, the first multiplexer module 33, and the second multiplexer module 34. After a predetermined time period T from the start time, the control module 32 outputs a state setting signal to the first multiplexer module 33 and the second multiplexer module 34 to control one of the first multiplexer module 33 and the second multiplexer module 34 to switch to the first state and the other to the second state. In at least one embodiment of the present invention, the control module 32 controls the first multiplexer module 33 and the second multiplexer module 34 to alternately maintain the first state based on the state setting signal. For example, the touch sensing phase Ts may include at least one first time period and at least one second time period, which are alternately arranged. During the first time period, the control module 32 controls the first multiplexer module 33 to switch to the first state and the second multiplexer module 34 to switch to the second state based on the state setting signal, so that the first electrodes 121_1-121_m function as the driving electrodes and the second electrodes 123_1-123_n function as the sensing electrodes. During the second time period, the control module 32 switches the first multiplexer module 33 to the second state and switches the second multiplexer module 34 to the first state, so that the first electrodes 121_1 to 121_m serve as the sensing electrodes and the second electrodes 123_1 to 123_n serve as the driving electrodes.

[0041] The first multiplexing module 33 is electrically connected to the first electrodes 121_1-121_m, the control module 32, the touch driving module 35, and the touch sensing module 36. The first multiplexing module 33 can switch between a first state and a second state. In the first state, the first multiplexing module 33 establishes an electrical connection between the touch driving module 35 and the first electrodes 121_1-121_m to set the first electrodes 121_1-121_m as the driving electrodes. In the second state, the first multiplexing module 33 establishes an electrical connection between the touch sensing module 36 and the first electrodes 121_1-121_m to set the first electrodes 121_1-121_m as the sensing electrodes.

[0042] The second multiplexing module 34 is electrically connected to the second electrodes 123_1-123_n, the control module 32, the touch driving module 35, and the touch sensing module 36. The second multiplexing module 34 can switch between a first state and a second state. In the first state, the second multiplexing module 34 establishes an electrical connection between the touch driving module 35 and the second electrodes 123_1-123_n to set the second electrodes 123_1-123_n as the driving electrodes. In the second state, the second multiplexing module 34 establishes an electrical connection between the touch sensing module 36 and the second electrodes 123_1-123_n to set the second electrodes 123_1-123_n as the sensing electrodes.

[0043] The touch driver module 35 is electrically connected to the first multiplexer module 33 and the second multiplexer module 34. The touch driver module 35 is configured to provide the plurality of drive signals to the drive electrodes via the first multiplexer module 33 or the second multiplexer module 34 in the first state. The plurality of drive signals are periodic in-phase signals. In at least one embodiment of the present invention, the in-phase signals are pulse signals having the same frequency, amplitude, and phase. It is understood that the amplitude and phase of the in-phase signals may slightly deviate due to signal loss or other reasons, but the frequency of the in-phase signals must remain consistent.

[0044] The touch sensing module 36 is electrically connected to the first multiplexer module 33 and the second multiplexer module 34. The touch sensing module 36 is configured to receive the sensing capacitance transmitted by the first multiplexer module 33 or the second multiplexer module 34 in the second state, convert the sensing capacitance into a digital signal, and then provide the digital signal to the digital signal processing module 37.

[0045] The digital signal processing module 37 is electrically connected to the touch sensing module 36. The digital signal processing module 37 is used to analyze the digital signal to obtain the touch position of the touch object on the capacitive touch display device 1. In at least one embodiment of the present invention, the digital signal processing module 37 calculates the difference between the digital signal and the reference signal, and calculates the touch position of the touch object on the capacitive touch display device 1 based on the difference through a centroid algorithm or the like. The reference signal is the value of the sensing capacitance of the first electrodes 121_1 to 121_m or the second electrodes 123_1 to 123_n converted into a digital signal in the absence of touch. The centroid algorithm is a weighted average based on the arrangement sequence number of the first electrodes 121_1 to 121_m or the second electrodes 123_1 to 123_n and the difference.

[0046] Please refer to Figures 4 and 5, which are schematic diagrams of the digital signals corresponding to the sensing electrodes RX_1-RX_10 in both the no-touch and touch conditions. In the no-touch condition, the digital signals corresponding to the sensing electrodes RX_1-RX_10 show little difference. In the touch condition, the digital signals corresponding to the sensing electrodes RX_5-RX_8 increase significantly. Therefore, the touch position of the touching object on the capacitive touch display device 1 is the position corresponding to the sensing electrodes RX_5-RX_8.

[0047] Specifically, when the first multiplexer selection module 33 is in the first state and the second multiplexer selection module 34 is in the second state, the touch driving module 35 is used to output the plurality of driving signals to the first electrodes 121_1 to 121_m, the touch sensing module 36 receives the sensing capacitance of the second electrodes 123_1 to 123_n, and the digital signal processing module 37 calculates the capacitance change of the sensing capacitance of the plurality of second electrodes 123_1 to 123_n, and obtains the coordinates of the touch object in the first direction X based on the capacitance change.

[0048] When the first multiplexer selection module 33 is in the second state and the second multiplexer selection module 34 is in the first state, the touch driving module 35 is used to output the multiple driving signals to the second electrodes 123_1 to 123_n, the touch sensing module 36 receives the sensing capacitance of the first electrodes 121_1 to 121_m, and the digital signal processing module 37 calculates the capacitance changes of the sensing capacitances of the multiple first electrodes 121_1 to 121_m, and obtains the coordinates of the touch object in the second direction Y based on the capacitance changes.

[0049] The digital signal processing module 37 uses the coordinates in the first direction X and the second direction Y as the two-dimensional coordinates of the touching object on the capacitive touch display device 1 to obtain the touch position of the touching object on the capacitive touch display device 1 .

[0050] In some embodiments, a portion of the plurality of driving electrodes may be grounded or in a suspended state, while the other driving electrodes continue to receive the plurality of driving signals. The driving electrodes in the grounded or suspended state do not affect the functions of the other driving electrodes or the sensing electrodes.

[0051] In some embodiments, the touch sensing control circuit 30 can receive the sensing capacitance generated by multiple sensing electrodes in a time-sharing manner. In this mode, the cost of the capacitive touch sensing device 1 is low, but the signal sensing time is slow. At the same time, a small portion of the multiple sensing electrodes can also be grounded, receive the drive signal, or be in a suspended state. The sensing electrodes that are grounded, receive the drive signal, or are in the suspended state do not affect the functions of the other driving electrodes or the sensing electrodes.

[0052] The capacitive touch display device 1 described above synchronizes the driving signal with the synchronization control signal output by the timing controller 40, so that the display image of the display panel 20 remains unchanged during the touch sensing stage Ts, thereby reducing the signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing stage Ts, thereby avoiding flickering or stripes on the display image of the capacitive touch display device 1.

[0053] Example 1

[0054] Please also refer to Figure 6, which is a schematic diagram of the waveforms of the display synchronization signal Vsync and the drive signals corresponding to the drive electrodes TX_1 to TX_5. In the first embodiment, the synchronization signal processing module 31 identifies the start time and the end time of the display synchronization signal Vsync and provides them to the control module 32. The control module 32 is configured to output the state setting signal to the first multiplexer module 33 and the second multiplexer module 34 after a predetermined time period T has passed since the start time, thereby controlling one of the first multiplexer module 33 and the second multiplexer module 34 to switch to the first state and the other to the second state. The time period Ta between the start time and the end time is greater than the predetermined time period T. That is, during the time period Ta between the start time and the end time, the display synchronization signal Vsync remains at a high level. After the predetermined time period T, the touch sensing control circuit 30 provides the multiple drive signals to the drive electrodes, and before the end time of the display synchronization signal Vsync, the touch sensing control circuit 30 stops providing the drive signals to the drive electrodes. The multiple driving signals are output simultaneously and have the same frequency, phase and amplitude, forming an in-phase signal. During the touch sensing stage Ts, the display synchronization signal Vsync is not refreshed, so that the display screen of the display panel 20 remains unchanged. Therefore, the capacitive touch display device 1 reduces the signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing stage Ts, thereby avoiding flickering or stripes on the display screen of the capacitive touch display device 1. In addition, in the time period Ta between the start time and the end time, the touch driving module 35 improves the touch sensing efficiency of the capacitive touch display device 1 by transmitting the driving signal twice to obtain the coordinates of the touch position, so that it has lower response delay and lower power consumption.

[0055] Example 2

[0056] Please also refer to Figure 7, which is a schematic diagram of the waveforms of the horizontal synchronization signal Hsync and the drive signals corresponding to the drive electrodes TX_1 to TX_5. In the second embodiment, the synchronization signal processing module 31 identifies the start and end times of the horizontal synchronization signal Hsync and provides them to the control module 32. The control module 32 is configured to output the state setting signal to the first multiplexer module 33 and the second multiplexer module 34 after the predetermined time period T has elapsed from the start time, thereby controlling one of the first multiplexer module 33 and the second multiplexer module 34 to switch to the first state and the other to the second state. The time period Ta between the start and end times is less than the predetermined time period T. That is, during the touch sensing phase Ts, the horizontal synchronization signal Hsync remains at a low level. In other words, during the touch sensing phase Ts, the horizontal synchronization signal Hsync is not refreshed, causing the display image of the display panel 20 to remain unchanged. Furthermore, within a cycle T1 of the horizontal synchronization signal Hsync, the touch driver module 35 only transmits the drive signal once. After the predetermined time period T, the touch sensing control circuit 30 provides the plurality of drive signals to the drive electrodes, and before the next start time of the horizontal synchronization signal Hsync, the touch sensing control circuit 30 stops providing the drive signals to the drive electrodes. When the frequency of the display synchronization signal Vsync changes, the capacitive touch display device 1 synchronizes the drive signals with the horizontal synchronization signal Hsync, thereby reducing the difficulty of synchronizing the drive signals with the synchronization control signal and reducing signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing phase Ts, thereby preventing flickering or stripes on the display screen of the capacitive touch display device 1.

[0057] Example 3

[0058] Please also refer to Figure 8, which is a schematic diagram of the waveforms of the display synchronization signal Vsync, the row synchronization signal Hsync, and the drive signals corresponding to the drive electrodes TX_1 to TX_5. In the third embodiment, the synchronization signal processing module 31 identifies the start and end times of the display synchronization signal Vsync and provides them to the control module 32. The control module 32 is configured to output the state setting signal to the first multiplexer module 33 and the second multiplexer module 34 after the predetermined time period T has passed since the start time, thereby controlling one of the first multiplexer module 33 and the second multiplexer module 34 to switch to the first state and the other to the second state. The time period Ta between the start and end times is less than the predetermined time period T. That is, during the time period Ta between the start and end times, the display synchronization signal Vsync remains at a high level. During the touch sensing phase Ts, both the display synchronization signal Vsync and the row synchronization signal Hsync remain at a low level. That is, during the touch sensing phase Ts, the row synchronization signal Hsync is not refreshed, so that the display screen of the display panel 20 remains unchanged. After the predetermined time period T, the touch sensing control circuit 30 provides multiple drive signals to the drive electrodes, and before the next starting moment of the display synchronization signal Vsync, the touch sensing control circuit 30 stops providing the drive signals to the drive electrodes. The multiple drive signals are output simultaneously and have the same frequency, phase, and amplitude, forming in-phase signals. In the third embodiment, within the predetermined time period T, the display panel 20 completes the scanning of a frame of image; after the predetermined time period T, the display panel 20 maintains the current display screen and does not perform the scanning of the next frame of image. Therefore, the capacitive touch display device 1 reduces the signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing phase Ts, thereby avoiding flickering or striping of the display screen of the capacitive touch display device 1. In addition, within any period T2 of the display synchronization signal Vsync, the touch driving module 35 transmits the synchronous driving signal, thereby improving the touch sensing efficiency of the capacitive touch display device 1 and enabling it to have lower response delay and lower power consumption.

[0059] Please refer to FIG9 , which is a flow chart of a touch sensing method. In at least one embodiment of the present invention, the touch sensing method is applied to the capacitive touch display device 1. The touch sensing method comprises the following steps:

[0060] Step S91 : obtaining a synchronization control signal from the timing controller 40 .

[0061] In at least one embodiment of the present invention, the synchronization control signal may include a display synchronization signal Vsync and a line synchronization signal Hsync. Within one cycle of the display synchronization signal Vsync, the display panel 20 completes scanning of one frame of an image; within one cycle of the line synchronization signal Hsync, the display panel 20 completes scanning of one line of an image. Within one cycle of the display synchronization signal Vsync, the number of cycles of the line synchronization signal Hsync matches the number of rows of the display panel 20. That is, within one cycle of the display synchronization signal Vsync, images of all rows of the display panel 20 are scanned. The synchronization signal processing module 31 identifies the start time and the end time of one of the display synchronization signal Vsync and the line synchronization signal Hsync.

[0062] Step S92: Synchronize the driving signal and the synchronization control signal.

[0063] Please also refer to FIG. 10 . In at least one embodiment of the present invention, the step of synchronizing the driving signal with the synchronization control signal includes:

[0064] S921: Identify the start time and end time of the synchronization control signal.

[0065] In at least one embodiment of the present invention, the start time is the time when the rising edge of the synchronization control signal is generated in one cycle, and the end time is the time when the falling edge of the synchronization control signal is generated in the same cycle.

[0066] S922 , setting the state setting signal to be output after a predetermined time period T has passed since the start time, so as to set one of the first electrodes 121_1 ˜ 121_m and the second electrodes 123_1 ˜ 123_n as a driving electrode and the other as a sensing electrode.

[0067] In the first embodiment, when the synchronization control signal is the display synchronization signal Vsync, the time period Ta between the start moment and the end moment is greater than the predetermined time period T. That is, in the time period Ta between the start moment and the end moment, the display synchronization signal Vsync maintains a high level unchanged. After the predetermined time period T, a plurality of drive signals are provided to the drive electrodes, and before the end moment of the display synchronization signal Vsync, the drive signal is stopped from being provided to the drive electrodes. The plurality of drive signals are output simultaneously and have the same frequency, phase, and amplitude, constituting in-phase signals, that is, in the touch sensing stage Ts, the display synchronization signal Vsync is not refreshed, so that the display screen of the display panel 20 remains unchanged. Therefore, the capacitive touch display device 1 reduces the signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing stage Ts, thereby avoiding flickering or stripes on the display screen of the capacitive touch display device 1. In addition, in the time period Ta between the start time and the end time, the touch driving module 35 transmits the driving signal multiple times, thereby improving the touch sensing efficiency of the capacitive touch display device 1 and enabling it to have lower response delay and lower power consumption.

[0068] In a second embodiment, when the synchronization control signal is the horizontal synchronization signal Hsync, the time period Ta between the start time and the end time is less than the predetermined time period T. That is, during the touch sensing phase Ts, the horizontal synchronization signal Hsync remains unchanged at a low level. In other words, during the touch sensing phase Ts, the horizontal synchronization signal Hsync is not refreshed, so that the display image of the display panel 20 remains unchanged. After the predetermined time period T, the plurality of drive signals are provided to the drive electrodes, and before the next start time of the horizontal synchronization signal Hsync, the supply of the drive signals to the drive electrodes is stopped. The plurality of drive signals are output simultaneously and have the same frequency, phase, and amplitude, forming in-phase signals. In addition, within one cycle T1 of the horizontal synchronization signal Hsync, the touch drive module 35 transmits the drive signal only once. When the frequency of the display synchronization signal Vsync changes, the capacitive touch display device 1 synchronizes the drive signal with the horizontal synchronization signal Hsync, thereby reducing the difficulty of synchronizing the drive signal with the synchronization control signal and reducing signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing stage Ts, thereby avoiding flickering or stripes on the display screen of the capacitive touch display device 1.

[0069] In a third embodiment, when the synchronization control signal is the display synchronization signal Vsync, the time period Ta between the start time and the end time is less than the predetermined time period T. That is, during the time period Ta between the start time and the end time, the display synchronization signal Vsync remains at a high level. After the predetermined time period T, multiple drive signals are provided to the drive electrodes, and before the next start time of the display synchronization signal Vsync, the supply of the drive signals to the drive electrodes ceases. The multiple drive signals are output simultaneously and have the same frequency, phase, and amplitude, forming in-phase signals. During the touch sensing phase Ts, the display synchronization signal Vsync and the horizontal synchronization signal Hsync remain at a low level. That is, during the touch sensing phase Ts, the horizontal synchronization signal Hsync is not refreshed, so that the display image of the display panel 20 remains unchanged. In the third embodiment, within the predetermined time period T, the display panel 20 completes scanning of one frame of image; after the predetermined time period T, the display panel 20 maintains the current display image and does not scan the next frame of image. Therefore, the capacitive touch display device 1 reduces signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing phase Ts, thereby preventing flickering or streaking on the display screen of the capacitive touch display device 1. Furthermore, within any period T2 of the display synchronization signal Vsync, the touch driver module 35 transmits the synchronized drive signal, thereby improving the touch sensing efficiency of the capacitive touch display device 1, resulting in lower response delay and lower power consumption.

[0070] S93 , providing the driving signal to the driving electrode, receiving the sensing capacitance of the sensing electrode, and converting the sensing capacitance into a digital signal.

[0071] The drive signals corresponding to the different drive electrodes are all periodic in-phase signals. In at least one embodiment of the present invention, the in-phase signals are pulse signals having the same frequency, amplitude, and phase. It is understood that the amplitude and phase of the in-phase signals may slightly deviate due to signal loss or other reasons, but the frequency of the in-phase signals must remain consistent.

[0072] S94 , analyzing the digital signal to obtain a touch position of the touching object on the capacitive touch display device 1 .

[0073] In at least one embodiment of the present invention, the touch position of the touch object on the capacitive touch display device 1 is determined by calculating the difference between the digital signal and a reference signal, and applying a centroid algorithm based on the difference. The reference signal is the value of the sensed capacitance corresponding to the sensing electrode converted into a digital signal in the absence of touch. The centroid algorithm performs a weighted average based on the arrangement sequence of the sensing electrodes and the difference.

[0074] The above-mentioned touch sensing method synchronizes the driving signal with the synchronization control signal output by the timing controller 40, so that the display image of the display panel 20 remains unchanged during the touch sensing stage Ts, thereby reducing the signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing stage Ts, thereby avoiding flickering or stripes on the display image of the capacitive touch display device 1.

[0075] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A capacitive touch display device, comprising a touch panel, a display panel, a touch sensing control circuit and a timing controller; the touch panel is stacked with a cover plate and a touch electrode layer in sequence from top to bottom; the touch electrode layer is patterned to form a plurality of first electrodes arranged along a first direction and a plurality of second electrodes arranged along a second direction; the touch sensing control circuit is electrically connected to the first electrodes and the second electrodes; characterized in that: In the touch sensing stage, one of the first electrode and the second electrode is used as a driving electrode, and the other is used as a sensing electrode; the touch sensing control circuit is used to provide a driving signal to the multiple driving electrodes in the touch sensing stage, and receive the sensing capacitance generated by each of the sensing electrodes; the timing controller outputs a synchronization control signal, and the synchronization control signal includes a display synchronization signal and a line synchronization signal. The display panel completes the scanning of a line of image in one cycle of the line synchronization signal, and completes the image scanning of all lines of the display panel once in one cycle of the display synchronization signal; the touch sensing control circuit is also used to synchronize the driving signal with the synchronization control signal, so that the display panel stops refreshing the display screen in the touch sensing stage, and the touch sensing control circuit simultaneously provides multiple driving signals to the driving electrodes; wherein the multiple driving signals are periodic in-phase signals, and the in-phase signal is a pulse signal with the same frequency, phase and amplitude.

2. The capacitive touch display device according to claim 1, wherein: The touch sensing control circuit includes a synchronous signal processing module, a control module, a first multi-way selection module, a second multi-way selection module, a touch driving module and a touch sensing module; the synchronous signal processing module identifies the starting time and the ending time of the synchronous control signal in a cycle and provides them to the control module; the control module outputs a state setting signal to the first multi-way selection module and the second multi-way selection module after a predetermined time period from the starting time, so as to control one of the first multi-way selection module and the second multi-way selection module to switch to the first state and the other to switch to the second state; wherein, in the first state, the first multi-way selection module establishes In the second state, the first multi-way selection module establishes an electrical connection between the touch driving module and the first electrode to set the first electrode as the driving electrode; in the second state, the first multi-way selection module establishes an electrical connection between the touch sensing module and the first electrode to set the first electrode as the sensing electrode; in the first state, the second multi-way selection module establishes an electrical connection between the touch driving module and the second electrode to set the second electrode as the sensing electrode; in the second state, the second multi-way selection module establishes an electrical connection between the touch sensing module and the second electrode to set the second electrode as the driving electrode.

3. The capacitive touch display device according to claim 2, wherein: The synchronization signal processing module identifies the start time and the end time of the display synchronization signal; wherein the time period between the start time and the end time is greater than the predetermined time period; within the time period between the start time and the end time, the display synchronization signal maintains a high level unchanged, after the predetermined time period, the touch sensing control circuit provides a plurality of the drive signals to the drive electrodes, and before the end time of the display synchronization signal, the touch sensing control circuit stops providing the drive signals to the drive electrodes.

4. The capacitive touch display device according to claim 2, wherein: The synchronization signal processing module identifies the start time and the end time of the row synchronization signal; wherein the time period between the start time and the end time is less than the predetermined time period; within the time period between the start time and the end time, the row synchronization signal maintains a low level unchanged, after the predetermined time period, the touch sensing control circuit provides a plurality of the drive signals to the drive electrodes, and before the next start time of the row synchronization signal, the touch sensing control circuit stops providing the drive signals to the drive electrodes.

5. The capacitive touch display device according to claim 2, wherein: The synchronization signal processing module identifies the start time and the end time of the display synchronization signal; wherein the time period between the start time and the end time is less than the predetermined time period; within the time period between the start time and the end time, the display synchronization signal maintains a high level unchanged; within the touch sensing stage, the display synchronization signal and the row synchronization signal are maintained at a low level state, and after the predetermined time period, the touch sensing control circuit provides a plurality of the drive signals to the drive electrodes, and before the next start time of the display synchronization signal, the touch sensing control circuit stops providing the drive signals to the drive electrodes.

6. The capacitive touch display device according to claim 2, wherein: The touch sensing stage includes at least one first time period and at least one second time period, and the two are alternately arranged; in the first time period, the control module controls the first multi-way selection module to switch to the first state and the second multi-way selection module to switch to the second state according to the state setting signal, so that the first electrode serves as the driving electrode and the second electrode serves as the sensing electrode; In the second time period, the control module switches the first multi-way selection module to the second state, and switches the second multi-way selection module to the first state, so that the first electrode serves as the sensing electrode and the second electrode serves as the driving electrode.

7. A touch sensing method, applied to a capacitive touch display device; the capacitive touch display device comprises a touch panel, a display panel, a touch sensing control circuit and a timing controller; the touch panel is stacked with a cover plate and a touch electrode layer in sequence from top to bottom; the touch electrode layer is patterned to form a plurality of first electrodes arranged along a first direction and a plurality of second electrodes arranged along a second direction; the touch sensing control circuit is electrically connected to the first electrode and the second electrode; in a touch sensing stage, one of the first electrode and the second electrode is used as a driving electrode, and the other is used as a sensing electrode; The touch sensing control circuit is used for providing a driving signal to the plurality of driving electrodes during the touch sensing phase; The touch sensing method comprises: Acquire a synchronization control signal from the timing controller; the synchronization control signal includes a display synchronization signal and a line synchronization signal, the display panel completes scanning of a line of image within one cycle of the line synchronization signal, and completes scanning of images of all lines of the display panel once within one cycle of the display synchronization signal; The driving signal and the synchronization control signal are synchronously processed so that the display panel stops refreshing the display image during the touch sensing phase; At the same time, a plurality of driving signals are provided to the driving electrodes, and a sensing signal of the sensing electrodes is received. capacitance, and converting the sensing capacitance into a digital signal; wherein the driving signal is a periodic in-phase signal, and the in-phase signal is a pulse signal with the same frequency, phase and amplitude; The digital signal is analyzed to obtain a touch position of the touch object on the capacitive touch display device.

8. The touch sensing method according to claim 7, wherein: The step of synchronously processing the driving signal and the synchronous control signal comprises: Identifying the start time and the end time of the synchronization control signal; The state setting signal is set to be output after a predetermined period of time has passed since the start time, so as to set one of the first electrode and the second electrode as a driving electrode and the other as a sensing electrode.

9. The touch sensing method according to claim 7, wherein: When the synchronization control signal is a display synchronization signal, the start time and the end time of the display synchronization signal are identified; wherein the time period between the start time and the end time is greater than the predetermined time period; within the time period between the start time and the end time, the display synchronization signal is maintained at a high level so that the display panel stops refreshing the display screen, provides a plurality of the drive signals to the drive electrodes after the predetermined time period, and stops providing the drive signals to the drive electrodes before the end time of the display synchronization signal.

10. The touch sensing method according to claim 7, wherein: When the synchronization control signal is a line synchronization signal, the start time and the end time of the line synchronization signal are identified; wherein the time period between the start time and the end time is less than the predetermined time period; within the time period between the start time and the end time, the line synchronization signal is maintained at a low level so that the display panel stops refreshing the display screen, provides a plurality of the drive signals to the drive electrodes after the predetermined time period, and stops providing the drive signals to the drive electrodes before the next start time of the line synchronization signal.

11. The touch sensing method according to claim 7, wherein: The synchronization control signal includes a display synchronization signal and a row synchronization signal; the synchronization signal processing module identifies the start time and the end time of the display synchronization signal; wherein the time period between the start time and the end time is less than the predetermined time period; within the time period between the start time and the end time, the display synchronization signal maintains a high level unchanged; within the touch sensing stage, the display synchronization signal and the row synchronization signal are maintained in a low level state, so that the display panel stops refreshing the display screen, provides a plurality of the drive signals to the drive electrodes after the predetermined time period, and stops providing the drive signals to the drive electrodes before the next start time of the display synchronization signal.

12. The touch sensing method according to claim 7, wherein: The touch sensing stage includes at least one first time period and at least one second time period, and the two are alternately arranged; in the first time period, the first electrode serves as the driving electrode, and the second electrode serves as the sensing electrode; During the second time period, the first electrode serves as the sensing electrode, and the second electrode serves as the driving electrode.

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