Capacitive touch display device and touch sensing method

Abstract

A capacitive touch display device and a touch sensing method. 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. The touch electrode layer forms 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 with the first electrodes and the second electrodes. In a touch sensing stage, one of the first electrodes and the second electrodes is a driving electrode and the other is a sensing electrode. The touch sensing control circuit synchronously processes a plurality of driving signals with a synchronous control signal output by the timing controller in the touch sensing stage, simultaneously provides the plurality of driving signals to the plurality of driving electrodes, and receives a sensing capacitance generated by each sensing electrode, so that the display panel stops refreshing a display image in the touch sensing stage. The plurality of driving signals are synchronous signals.

Description

Technical Field

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

[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 sequentially. The first display electrode layer, dielectric layer, light-emitting layer, and second display electrode layer constitute the display structure. Because the first display electrode layer and the touch electrode layer are close together, when a driving voltage is applied to the touch electrode layer for touch sensing, a large capacitance is generated between the touch electrode in the touch electrode layer and the first display electrode in the first display electrode layer. This interferes with the first display electrode, causing the displayed image to flicker or exhibit stripes, thus negatively impacting the display structure. Summary of the Invention

[0003] The main objective of this 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 avoid the negative impact of touch electrodes on the display structure when a driving signal is applied.

[0004] A capacitive touch display device includes a touch panel, a display panel, a touch sensing control circuit, and a timing controller. The touch panel has 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 and second electrodes. During the touch sensing phase, one of the first and second electrodes serves as a driving electrode, and the other as a sensing electrode. The touch sensing control circuit provides a driving signal to the plurality of driving electrodes during the touch sensing phase and receives the sensing capacitance generated by each of the sensing electrodes. The sequence controller outputs a synchronization control signal, which includes a display synchronization signal and a row synchronization signal. Within one cycle of the row synchronization signal, the display panel completes a scan of one row of images. Within one cycle of the display synchronization signal, it completes a scan of all rows of images on the display panel. 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 during the touch sensing phase. The touch sensing control circuit also provides multiple driving signals to the driving electrodes simultaneously. The multiple driving signals are in-phase signals, which are pulse signals with the same frequency, phase, and amplitude.

[0005] Furthermore, to achieve the above objectives, the present invention also proposes a touch sensing method 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 has 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; during the touch sensing stage, one of the first electrodes and the second electrodes serves as a driving electrode, and the other serves as a sensing electrode; the touch sensing control circuit is used to provide driving signals to the plurality of driving electrodes during the touch sensing stage; the touch sensing method includes:

[0006] The synchronization control signal is obtained from the timing controller; the synchronization control signal includes a display synchronization signal and a row synchronization signal. Within one cycle of the row synchronization signal, the display panel completes a scan of one row of images, and within one cycle of the display synchronization signal, it completes a scan of all rows of images on the display panel once.

[0007] The driving signal and the synchronization control signal are synchronized so that the display panel stops refreshing the display screen during the touch sensing phase;

[0008] Simultaneously, multiple driving signals are provided to the driving electrode, the sensing capacitance of the sensing electrode is received, and the sensing capacitance is converted 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;

[0009] The touch position of the object on the capacitive touch display device is obtained by analyzing the digital signal.

[0010] The above-described 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 screen of the display panel remains unchanged during the touch sensing stage, thereby reducing signal interference between the touch electrode layer and the display panel during the touch sensing stage and thus avoiding flickering or stripe phenomena in the display screen of the capacitive touch display device. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of a capacitive touch display device according to a preferred embodiment of the present invention.

[0013] Figure 2 for Figure 1 A schematic diagram of the capacitive touch display device described herein.

[0014] Figure 3 for Figure 1 A cross-sectional view of the capacitive touch display device described herein along the III-III direction.

[0015] Figure 4 for Figure 2 A schematic diagram of the digital signals corresponding to the multiple sensing electrodes in the absence of touch.

[0016] Figure 5 for Figure 2 A schematic diagram of the digital signals corresponding to the multiple sensing electrodes in the case of touch.

[0017] Figure 6 for Figure 2 The diagram shows the waveforms of the synchronization signal and the multiple drive signals.

[0018] Figure 7 for Figure 2 The waveform diagrams of the line synchronization signal and the multiple drive signals are shown in the figure.

[0019] Figure 8 for Figure 2 The waveform diagrams of the display synchronization signal, the line synchronization signal, and the plurality of drive signals are shown in the figure.

[0020] Figure 9 This is a flowchart of a preferred embodiment of the touch sensing method of the present invention.

[0021] Figure 10 for Figure 9 Detailed flowchart of S92.

[0022] Explanation of main component symbols

[0023] Capacitive touch display device 1

[0024] Touch panel 10

[0025] Display panel 20

[0026] Cover plate 11

[0027] Touch electrode layer 12

[0028] First display electrode layer 21

[0029] Light-emitting layer 22

[0030] Second display electrode layer 23

[0031] Dielectric layer 24

[0032] First electrode 121_1~121_m

[0033] Second electrode 123_1~123_n

[0034] Drive electrodes TX_1~TX_5

[0035] Sensing electrodes RX_1~RX_10

[0036] Touch display area 101

[0037] Non-display area 103

[0038] Touch sensing control circuit 30

[0039] Touch sensing line 301

[0040] Synchronous signal processing module 31

[0041] Control module 32

[0042] First multi-way selection module 33

[0043] Second multiplexing module 34

[0044] Touch driver module 35

[0045] Touch sensing module 36

[0046] Digital signal processing module 37

[0047] Timing controller 40

[0048] Touch sensing stage Ts

[0049] Scheduled time period T

[0050] Steps S91-S94

[0051] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0052] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0053] The terms "first," "second," and "third," etc., used in the specification and accompanying drawings of this invention are for distinguishing different objects, not for describing a specific order. Furthermore, the term "comprising," and any variations thereof, are intended to cover non-exclusive inclusion.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0055] The specific embodiments of the capacitive touch display device and touch sensing method of the present invention will be described below with reference to the accompanying drawings.

[0056] Please see Figure 1 This is a schematic diagram of a capacitive touch display device 1. The capacitive touch display device 1 can be a mobile device such as a personal computer, tablet computer, smartphone, personal digital assistant (PDA), game console, interactive network 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 may further include one or more of the following functions: fingerprint recognition, display function, and camera function.

[0057] The capacitive touch display device 1 includes a touch panel 10 and a display panel 20.

[0058] The touch panel 10 is used to sense the user's touch operation. The touch panel 10 includes a cover plate 11 and a touch electrode layer 12 stacked from top to bottom.

[0059] The cover plate 11 can be a glass substrate or other transparent substrate with high strength and high hardness. In at least one embodiment of the present invention, the cover plate 11 can be made of materials such as polycarbonate (PC), polyester (PET), polymethyl methacrylate (PMMA), cycloolefin copolymer (COC), or polyether sulfone (PES).

[0060] Please refer to the following: Figure 2 This is a schematic diagram of the touch electrode layer 12. 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. Here, 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, and 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 may intersect at other angles. During the touch sensing stage Ts (e.g. Figure 4-6 At any given time within the range shown, one of the first electrodes 121_1 to 121_m and the second electrodes 123_1 to 123_n serves as a driving electrode, and the other serves as a sensing electrode. When a grounded conductor (e.g., a finger or stylus) is present on the cover plate 11, an induced capacitance is generated between the sensing electrode and the grounded 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 mutually capacitive touch sensing structure.

[0061] Please refer to the following: Figure 3This is a 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 may also be other types of display panels, such as liquid crystal display panels, field emission display panels, plasma display panels, and electrophoretic display panels.

[0062] The first display electrode layer 21 is disposed on the side of the dielectric layer 24 away from the touch electrode layer 12. The first display electrode layer 21 may be patterned to form a plurality of first display electrodes (e.g., cathodes). The light-emitting layer 22 is disposed between the first display electrode layer 21 and the second display electrode layer 23, and is located on the 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), an emissive layer (EML), and an electron transport layer (ETL). The second display electrode layer 23 is disposed on the side of the light-emitting layer 22 away from the first display electrode layer 21. The second display electrode layer 23 may be patterned to form a plurality of second display electrodes (e.g., anodes).

[0063] Further, refer to Figure 1 and Figure 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 can extend into the non-display area 103.

[0064] refer to Figure 2 The capacitive touch display device 1 further includes a touch sensing control circuit 30 and a timing controller 40. The touch sensing control circuit 30 can be disposed within the non-display area 103 and is electrically connected to a plurality of first electrodes 121_1 to 121_m and a plurality of second electrodes 123_1 to 123_n via touch sensing lines 301. The touch sensing control circuit 30 is used during the touch sensing phase Ts (e.g., Figures 6 to 8The touch sensing control circuit 30 provides a driving signal to the plurality of driving electrodes and receives the sensing capacitance generated by each of the sensing electrodes. Further, 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 synchronization processing, within one touch sensing phase Ts, the display panel 20 stops refreshing the display screen.

[0065] The touch sensing control circuit 30 includes a synchronous signal processing module 31, a control module 32, a first multiplexing module 33, a second multiplexing module 34, a touch driving module 35, a touch sensing module 36, and a digital signal processing module 37.

[0066] 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 this information to the control module 32. The synchronization control signal is a periodic pulse signal; the start time is the time when the rising edge of the synchronization control signal occurs within a cycle, and the end time is the time when the falling edge of the synchronization control signal occurs 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 line 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 line synchronization signal Hsync, the display panel 20 completes the scanning of one line of image. Within one cycle of the display synchronization signal Vsync, the number of cycles of the line synchronization signal Hsync is consistent with the number of lines of the display panel 20. That is, within one cycle of the display synchronization signal Vsync, the image scanning of all lines 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 line synchronization signal Hsync.

[0067] The control module 32 is electrically connected to the synchronization signal processing module 31, the first multiplexing module 33, and the second multiplexing module 34. After a predetermined time period T from the start time, the control module 32 outputs a state setting signal to the first multiplexing module 33 and the second multiplexing module 34 to control one of them to switch to a first state and the other to switch to a second state. In at least one embodiment of the present invention, the control module 32 controls the first multiplexing module 33 and the second multiplexing module 34 to alternately be in the first state according to 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 set. During the first time period, the control module 32 controls the first multiplexing module 33 to switch to the first state and the second multiplexing module 34 to switch to the second state according to the state setting signal, so that the first electrodes 121_1 to 121_m serve as the driving electrodes, and the second electrodes 123_1 to 123_n serve as the sensing electrodes. During the second time period, the control module 32 switches the first multiplexing module 33 to the second state and switches the second multiplexing 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.

[0068] The first multiplexing module 33 is electrically connected to the first electrodes 121_1 to 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 to 121_m to set the first electrodes 121_1 to 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 to 121_m to set the first electrodes 121_1 to 121_m as the sensing electrodes.

[0069] The second multiplexing module 34 is electrically connected to the second electrodes 123_1 to 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 to 123_n to set the second electrodes 123_1 to 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 to 123_n to set the second electrodes 123_1 to 123_n as the sensing electrodes.

[0070] The touch driving module 35 is electrically connected to the first multiplexer module 33 and the second multiplexer module 34. The touch driving module 35 is used to provide multiple driving signals to the driving electrode through the first multiplexer module 33 or the second multiplexer module 34 in the first state. These multiple driving 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 have slight deviations due to signal loss or other reasons, but the frequency of the in-phase signals must remain consistent.

[0071] 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 used to receive the sensing capacitance transmitted by the first multiplexer module 33 or the second multiplexer module 34 in the second state, and convert the sensing capacitance into a digital signal and provide it to the digital signal processing module 37.

[0072] The digital signal processing module 37 is electrically connected to the touch sensing module 36. The digital signal processing module 37 analyzes the digital signal to obtain the touch position of the 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 a reference signal, and calculates the touch position of the object on the capacitive touch display device 1 based on the difference using a centroid algorithm, etc. The reference signal is the value of the sensing capacitance of the first electrodes 121_1~121_m or the second electrodes 123_1~123_n converted into a digital signal when there is no touch. The centroid algorithm is a weighted average based on the sequence number of the first electrodes 121_1~121_m or the second electrodes 123_1~123_n and the difference.

[0073] Please refer to the following: Figure 4 and Figure 5 This diagram illustrates the digital signals corresponding to the sensing electrodes RX_1-RX_10 under both touch-free and touch-enabled conditions. Under touch-free conditions, the differences in the digital signals corresponding to the multiple sensing electrodes RX_1-RX_10 are not significant. Under touch-enabled conditions, the digital signals corresponding to the sensing electrodes RX_5-RX_8 are significantly increased. Therefore, the touch position of the object on the capacitive touch display device 1 is the position corresponding to the sensing electrodes RX_5-RX_8.

[0074] Specifically, when the first multiplexing module 33 is in the first state and the second multiplexing module 34 is in the second state, the touch driving module 35 is used to output multiple 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, the digital signal processing module 37 calculates the capacitance change of the sensing capacitance of the multiple second electrodes 123_1 to 123_n, and obtains the coordinates of the touched object in the first direction X based on the capacitance change.

[0075] When the first multiplexing module 33 is in the second state and the second multiplexing module 34 is in the first state, the touch driving module 35 is used to output 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, the digital signal processing module 37 calculates the capacitance change of the sensing capacitance of the multiple first electrodes 121_1 to 121_m, and obtains the coordinate of the touched object in the second direction Y based on the capacitance change.

[0076] 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 touch object on the capacitive touch display device 1, thereby obtaining the touch position of the touch object on the capacitive touch display device 1.

[0077] In some embodiments, a small subset of the plurality of drive electrodes may be grounded or in a floating state, while the other drive electrodes continue to receive the plurality of drive signals. The drive electrodes that are grounded or in the floating state do not affect the functionality of the other drive electrodes or the sensing electrodes.

[0078] In some embodiments, the touch sensing control circuit 30 can receive the sensing capacitance generated by multiple sensing electrodes in a time-division multiplexing manner. In this mode, the capacitive touch sensing device 1 has a lower cost, but the signal sensing time is slower. Meanwhile, a small portion of the multiple sensing electrodes can also be grounded, receive the drive signal, or be in a floating state. The sensing electrodes that are grounded, receive the drive signal, or are in the floating state do not affect the function of the other drive electrodes or sensing electrodes.

[0079] 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 screen of the display panel 20 remains unchanged during the touch sensing phase Ts. This reduces signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing phase Ts, thereby preventing flickering or stripes from occurring on the display screen of the capacitive touch display device 1.

[0080] Example 1

[0081] Please refer to the following: Figure 6This is a waveform diagram of the display synchronization signal Vsync and the driving signals corresponding to the driving electrodes TX_1 to TX_5. In Embodiment 1, 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 sets that after a predetermined time period T from the start time, it outputs the state setting signal to the first multiplexing module 33 and the second multiplexing module 34 to control one of the first multiplexing module 33 and the second multiplexing 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 multiple driving signals to the driving electrodes, and before the end time of the display synchronization signal Vsync, the touch sensing control circuit 30 stops providing driving signals to the driving electrodes. The multiple driving signals are output simultaneously with identical frequency, phase, and amplitude, forming in-phase signals. During the touch sensing phase Ts, the display synchronization signal Vsync is not refreshed, ensuring that the display screen of the display panel 20 remains unchanged. 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 stripe phenomena on the display screen of the capacitive touch display device 1. Furthermore, during the time period Ta between the start and end times, the touch driving module 35 obtains the coordinates of the touch position by emitting the driving signals twice, improving the touch sensing efficiency of the capacitive touch display device 1 and resulting in lower response latency and lower power consumption.

[0082] Example 2

[0083] Please refer to the following: Figure 7This is a waveform diagram of the horizontal synchronization signal Hsync and the driving signals corresponding to the driving electrodes TX_1 to TX_5. In Embodiment 2, the synchronization signal processing module 31 identifies the start time and the end time of the horizontal synchronization signal Hsync and provides them to the control module 32. The control module 32 sets that after a predetermined time period T from the start time, it outputs the state setting signal to the first multiplexing module 33 and the second multiplexing module 34 to control one of the first multiplexing module 33 and the second multiplexing 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 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, so the display screen of the display panel 20 remains unchanged. Furthermore, within one cycle T1 of the horizontal synchronization signal Hsync, the touch driving module 35 only emits the driving signal once. After the predetermined time period T, the touch sensing control circuit 30 provides multiple driving signals to the driving electrodes. Before the next start time of the horizontal synchronization signal Hsync, the touch sensing control circuit 30 stops providing the driving signals to the driving electrodes. When the frequency of the display synchronization signal Vsync changes, the capacitive touch display device 1 synchronizes the driving signals with the horizontal synchronization signal Hsync, reducing the difficulty of synchronizing the driving 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 striping on the display screen of the capacitive touch display device 1.

[0084] Example 3

[0085] Please refer to the following: Figure 8This is a waveform diagram of the display synchronization signal Vsync, the horizontal synchronization signal Hsync, and the driving signals corresponding to the driving electrodes TX_1 to TX_5. In Embodiment 3, 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 sets that after a predetermined time period T from the start time, it outputs the state setting signal to the first multiplexing module 33 and the second multiplexing module 34 to control one of the first multiplexing module 33 and the second multiplexing 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 horizontal synchronization signal Hsync remain at a low level. In other words, during the touch sensing phase Ts, the horizontal synchronization signal Hsync is not refreshed, so the display screen of the display panel 20 remains unchanged. After the predetermined time period T, the touch sensing control circuit 30 provides multiple driving signals to the driving electrodes. Before the next start time of the display synchronization signal Vsync, the touch sensing control circuit 30 stops providing driving signals to the driving electrodes. The multiple driving signals are output simultaneously with the same frequency, phase, and amplitude, forming in-phase signals. In Embodiment 3, within the predetermined time period T, the display panel 20 completes the scanning of one 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 stripe phenomena in 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 emits the synchronized driving signal, improving the touch sensing efficiency of the capacitive touch display device 1, resulting in lower response latency and lower power consumption.

[0086] Please see Figure 9 This is a flowchart illustrating 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 includes the following steps:

[0087] Step S91: Obtain a synchronization control signal from the timing controller 40.

[0088] 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 the scanning of one frame of image; within one cycle of the line synchronization signal Hsync, the display panel 20 completes the scanning of one line of image. Within one cycle of the display synchronization signal Vsync, the number of cycles of the line synchronization signal Hsync is consistent with the number of lines of the display panel 20. That is, within one cycle of the display synchronization signal Vsync, all lines of image scanning of the display panel 20 are performed. 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.

[0089] Step S92: Synchronize the drive signal and the synchronization control signal.

[0090] Please refer to the following: Figure 10 In at least one embodiment of the present invention, the step of synchronizing the drive signal with the synchronization control signal includes:

[0091] S921, identify the start and end times of the synchronization control signal.

[0092] 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 within one cycle, and the end time is the time when the falling edge of the synchronization control signal is generated within the same cycle.

[0093] S922, the state setting signal is output after a predetermined time period T from 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 the driving electrode and the other as the sensing electrode.

[0094] In Example 1, when the synchronization control signal is the display synchronization signal Vsync, 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, multiple driving signals are provided to the driving electrodes, and before the end time of the display synchronization signal Vsync, the provision of driving signals to the driving electrodes is stopped. The multiple driving signals are output simultaneously with the same frequency, phase, and amplitude, forming in-phase signals. That is, during the touch sensing phase 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 phase Ts, thereby avoiding flickering or stripe phenomena on the display screen of the capacitive touch display device 1. In addition, during the time period Ta between the start time and the end time, the touch driving module 35 transmits the driving signal multiple times, which improves the touch sensing efficiency of the capacitive touch display device 1, giving it lower response latency and lower power consumption.

[0095] In Example 2, 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 at a low level. In other words, during the touch sensing phase Ts, the horizontal synchronization signal Hsync is not refreshed, ensuring that the display screen 20 remains unchanged. After the predetermined time period T, multiple driving signals are provided to the driving electrodes, and the provision of driving signals to the driving electrodes stops before the next start time of the horizontal synchronization signal Hsync. The multiple driving signals are output simultaneously with the same frequency, phase, and amplitude, forming in-phase signals. Furthermore, within one cycle T1 of the horizontal synchronization signal Hsync, the touch driving module 35 transmits the driving signal only once. When the frequency of the display synchronization signal Vsync changes, the capacitive touch display device 1 synchronizes the driving signal with the horizontal synchronization signal Hsync, reducing the difficulty of synchronizing the driving 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 stripe phenomena in the display screen of the capacitive touch display device 1.

[0096] In Embodiment 3, 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 driving signals are provided to the driving electrodes, and before the next start time of the display synchronization signal Vsync, the provision of driving signals to the driving electrodes is stopped. The multiple driving signals are output simultaneously with 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 screen of the display panel 20 remains unchanged. In Embodiment 3, during the predetermined time period T, the display panel 20 completes the scanning of one 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 signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing phase Ts, thereby preventing flickering or striping on the display screen of the capacitive touch display device 1. Furthermore, within any period T2 of the display synchronization signal Vsync, the touch driving module 35 emits the synchronized driving signal, improving the touch sensing efficiency of the capacitive touch display device 1, resulting in lower response latency and lower power consumption.

[0097] S93, provide the driving signal to the driving electrode, receive the sensing capacitance of the sensing electrode, and convert the sensing capacitance into a digital signal.

[0098] In this invention, the driving signals corresponding to different driving electrodes are all periodic in-phase signals. In at least one embodiment of the invention, the in-phase signal is a pulse signal with the same frequency, amplitude, and phase. It is understood that the amplitude and phase of the in-phase signal may have slight deviations due to signal loss or other reasons, but the frequency of the in-phase signal must remain consistent.

[0099] S94, Analyze the digital signal to obtain the touch position of the object on the capacitive touch display device 1.

[0100] In at least one embodiment of the present invention, the touch position of the touch object on the capacitive touch display device 1 is obtained by calculating the difference between the digital signal and the reference signal, and by using a centroid algorithm based on the difference. The reference signal is the value of the sensing capacitance corresponding to the sensing electrode converted into a digital signal in the absence of touch. The centroid algorithm is a weighted average based on the arrangement sequence of the sensing electrodes and the difference.

[0101] The above-described touch sensing method synchronizes the driving signal with the synchronization control signal output by the timing controller 40, so that the display screen of the display panel 20 remains unchanged during the touch sensing stage Ts. This reduces signal interference between the touch electrode layer 12 and the display panel 20 during the touch sensing stage Ts, thereby preventing flickering or stripes from occurring on the display screen of the capacitive touch display device 1.

[0102] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate 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 provided with 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 disposed along a first direction and a plurality of second electrodes disposed along a second direction; the touch sensing control circuit is electrically connected to the first electrodes and the second electrodes; characterized in that: During the touch sensing phase, 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 provides driving signals to the plurality of driving electrodes during the touch sensing phase and receives the sensing capacitance generated by each sensing electrode. The timing controller outputs a synchronization control signal, which includes a display synchronization signal and a row synchronization signal. Within one cycle of the row synchronization signal, the display panel completes a scan of one row of images, and within one cycle of the display synchronization signal, it completes a scan of all rows of images on the display panel. The touch sensing control circuit also synchronizes the driving signals 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 driving signals to the driving electrodes. The multiple driving signals are periodic in-phase signals, which are pulse signals with the same frequency, phase, and amplitude.

2. The capacitive touch display device as described in claim 1, characterized in that, The touch sensing control circuit includes a synchronization signal processing module, a control module, a first multiplexer module, a second multiplexer module, a touch driving module, and a touch sensing module. The synchronization signal processing module identifies the start and end times of the synchronization control signal within a cycle and provides them to the control module. The control module outputs a state setting signal to the first and second multiplexer modules after a predetermined time period from the start time, controlling one of the first and second multiplexer modules to switch to a first state and the other to switch to a second state. In the first state, the first multiplexer module establishes... In the first state, the first multiplexing 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 second multiplexing module establishes an electrical connection between the touch sensing module and the second electrode to set the second electrode as the sensing electrode; in the second state, the second multiplexing 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 as described in claim 2, characterized in that, The synchronization signal processing module identifies the start and end times of the display synchronization signal; wherein the time period between the start and end times is longer than the predetermined time period; during the time period between the start and end times, the display synchronization signal remains at a high level; after the predetermined time period, the touch sensing control circuit provides multiple driving signals to the driving electrodes; and before the end time of the display synchronization signal, the touch sensing control circuit stops providing the driving signals to the driving electrodes.

4. The capacitive touch display device as described in claim 2, characterized in that, The synchronization signal processing module identifies the start and end times of the line synchronization signal; wherein the time period between the start and end times is less than the predetermined time period; during the time period between the start and end times, the line synchronization signal remains at a low level; after the predetermined time period, the touch sensing control circuit provides multiple driving signals to the driving electrodes, and before the next start time of the line synchronization signal, the touch sensing control circuit stops providing the driving signals to the driving electrodes.

5. The capacitive touch display device as described in claim 2, characterized in that, The synchronization signal processing module identifies the start and end times of the display synchronization signal; wherein the time period between the start and end times is less than the predetermined time period; during the time period between the start and end times, the display synchronization signal remains at a high level; during the touch sensing phase, the display synchronization signal and the line synchronization signal remain at a low level; after the predetermined time period, the touch sensing control circuit provides multiple driving signals to the driving electrodes, and before the next start time of the display synchronization signal, the touch sensing control circuit stops providing the driving signals to the driving electrodes.

6. The capacitive touch display device as described in claim 2, characterized in that, The touch sensing phase includes at least one first time period and at least one second time period, which are alternately set; during the first time period, the control module controls the first multiplexing module to switch to the first state and the second multiplexing 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. During the second time period, the control module switches the first multiplexing module to the second state and switches the second multiplexing 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 in 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 is provided with 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 the touch sensing stage, one of the first electrodes and the second electrodes serves as a driving electrode, and the other serves as a sensing electrode; The touch sensing control circuit is used to provide driving signals to the plurality of driving electrodes during the touch sensing phase; The touch sensing method includes: The synchronization control signal is obtained from the timing controller; the synchronization control signal includes a display synchronization signal and a row synchronization signal. Within one cycle of the row synchronization signal, the display panel completes a scan of one row of images, and within one cycle of the display synchronization signal, it completes a scan of all rows of images on the display panel once. The driving signal and the synchronization control signal are synchronized so that the display panel stops refreshing the display screen during the touch sensing phase; Simultaneously, multiple driving signals are provided to the driving electrode, the sensing capacitance of the sensing electrode is received, and the sensing capacitance is converted 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 touch position of the object on the capacitive touch display device is obtained by analyzing the digital signal.

8. The touch sensing method as described in claim 7, characterized in that, The step of synchronizing the drive signal and the synchronization control signal includes: Identify the start and end times of the synchronization control signal; A state setting signal is output after a predetermined time period starting from the start time, so as to set one of the first electrode and the second electrode as the driving electrode and the other as the sensing electrode.

9. The touch sensing method as described in claim 8, characterized in that, When the synchronization control signal is a display synchronization signal, the start time and end time of the display synchronization signal are identified; wherein, the time period between the start time and the end time is longer than the predetermined time period; during the time period between the start time and the end time, the display synchronization signal is kept at a high level so that the display panel stops refreshing the display screen, multiple drive signals are provided to the drive electrodes after the predetermined time period, and the provision of drive signals to the drive electrodes is stopped before the end time of the display synchronization signal.

10. The touch sensing method as described in claim 8, characterized in that, When the synchronization control signal is a horizontal synchronization signal, the start time and end time of the horizontal synchronization signal are identified; wherein, the time period between the start time and the end time is less than the predetermined time period; during the time period between the start time and the end time, the horizontal synchronization signal is kept at a low level so that the display panel stops refreshing the display screen, multiple driving signals are provided to the driving electrodes after the predetermined time period, and the provision of driving signals to the driving electrodes is stopped before the next start time of the horizontal synchronization signal.

11. The touch sensing method as described in claim 8, characterized in that, The synchronization control signal includes a display synchronization signal and a line synchronization signal; the synchronization signal processing module identifies the start time and 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; during the time period between the start time and the end time, the display synchronization signal remains at a high level; during the touch sensing phase, the display synchronization signal and the line synchronization signal remain at a low level so that the display panel stops refreshing the display screen, provides multiple driving signals to the driving electrodes after the predetermined time period, and stops providing driving signals to the driving electrodes before the next start time of the display synchronization signal.

12. The touch sensing method as described in claim 7, characterized in that, The touch sensing phase includes at least one first time period and at least one second time period, which are alternately set; during 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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