Touch display driving apparatus

Abstract

A touch display driver according to one aspect of this disclosure is capable of maintaining a constant touch report rate in a variable refresh rate mode where the display refresh rate changes. The touch display driver includes: a timing controller that generates a first touch synchronization signal including a first touch scan period and a display drive period when operating in a default mode where the display refresh rate is a first frequency, and generates a second touch synchronization signal including a first touch scan period, a display drive period, a second touch scan period, and a dummy blank period when operating in a variable refresh rate mode where the display refresh rate decreases from the first frequency to a second frequency; a touch driver that performs touch scanning to generate raw touch data during the first and second touch scan periods; and a touch microcontroller unit that generates touch coordinates based on the raw touch data and reports the generated touch coordinates according to the touch report rate.

Description

Technical Field

[0001] This disclosure relates to display devices, and more specifically, to an embedded touch display. Background Technology

[0002] With the development of information technology, various display devices capable of visualizing information are being developed. Liquid crystal displays (LCDs), organic light-emitting diode (OLED) displays, and plasma display panel (PDP) displays are examples of displays that have been developed or are under development. These display devices are evolving to be able to appropriately display high-resolution images.

[0003] Display panels in various electronic devices (e.g., televisions, laptops, mobile devices, etc.) often employ touch functionality. In such cases, the display panel can be implemented as a flat panel display, and touch functionality can be achieved through a touch panel combined with the display panel. A touch panel refers to a panel that has the function of operating electronic devices or executing programs when a user presses text, images, icons, etc., with their fingers or a stylus.

[0004] For example, a touch panel can be configured to perform touch recognition capacitively; an example of a touch panel implementing capacitive touch recognition has been proposed as a "mutual capacitance type touch sensing device." For instance, the touch panel may have a configuration independent of the display panel and can be manufactured separately and combined with the display panel. As mentioned above, the configuration of combining the touch panel and the display panel leads to various difficulties such as process complexity and increased manufacturing costs.

[0005] To this end, the development of devices in which components for display and components for touch recognition can be shared is being promoted, with the embedded method being a representative example. The embedded method refers to implementing touch recognition using a configuration that implements touch functionality through pixels of a display panel. Pixels implemented using the embedded method perform both display and touch recognition. For example, in a device that provides both touch and display functionality (hereinafter referred to as a "touch display device"), touch operations and display operations can be operated in a time-division manner via display drive signals and touch drive signals.

[0006] According to one embodiment, the touch display device can operate in a variable refresh rate (VRR) mode that reduces power consumption or changes the display refresh rate (or display frame rate) depending on the type of image output by the touch display device.

[0007] However, there is a problem that when the display refresh rate of the touch display device changes, the touch report rate (or touch scan rate) changes, which may degrade the touch performance. Summary of the Invention

[0008] This disclosure aims to solve the above-mentioned problems and to provide a touch display driver device and touch display driver method that can maintain the touch report rate at a constant level in a variable refresh rate mode where the display refresh rate changes.

[0009] Furthermore, this disclosure aims to provide a touch display driver device and a touch display driver method that can stably maintain the touch report rate even when the degree of change in the display refresh rate is small.

[0010] A touch display driving device according to one aspect of the present disclosure for addressing the aforementioned technical problem includes: a timing controller that generates a first touch synchronization signal including a first touch scan period and a display driving period when operating in a default mode with a display refresh rate of a first frequency, and generates a second touch synchronization signal including a first touch scan period, a display driving period, a second touch scan period, and a dummy blank period when operating in a variable refresh rate mode with a display refresh rate decreasing from the first frequency to a second frequency; a touch driver that performs touch scanning to generate raw touch data during the first touch scan period and the second touch scan period; and a touch microcontroller unit that generates touch coordinates based on the raw touch data and reports the generated touch coordinates according to a touch report rate.

[0011] A touch display driving method according to one aspect of this disclosure for addressing the aforementioned technical problem includes the following steps: generating a first touch synchronization signal including a first touch scan period and a display driving period when operating in a default mode with a display refresh rate of a first frequency; performing a touch scan to generate touch coordinates during the first touch scan period and reporting the touch coordinates according to a touch report rate; generating a second touch synchronization signal including a first touch scan period, a display driving period, a second touch scan period, and a dummy blank period when operating in a variable refresh rate mode where the display refresh rate changes from the first frequency to a second frequency; and performing a touch scan to generate touch coordinates during the first touch scan period and the second touch scan period and reporting the touch coordinates according to a touch report rate. Attached Figure Description

[0012] The accompanying drawings are included to provide a further understanding of this disclosure and are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the disclosure and, together with the description, serve to illustrate the principles of the disclosure. In the drawings:

[0013] Figure 1 This is a block diagram of a touch display system including a touch display driving device according to one embodiment of the present disclosure;

[0014] Figure 2 This is a schematic diagram illustrating an example of an embedded touch panel using the mutual capacitance method;

[0015] Figure 3 This is a schematic diagram illustrating an example of an embedded touch panel using a self-capacitance method;

[0016] Figure 4 It is shown schematically. Figure 1 The block diagram shown illustrates the configuration of the timing controller;

[0017] Figure 5 This is a diagram showing the timing of the touch synchronization signal when the display refresh rate is the first frequency;

[0018] Figure 6 This is a diagram illustrating the timing of the touch synchronization signal when the display refresh rate changes from a first frequency to a second frequency;

[0019] Figure 7 This is a diagram illustrating the timing of the first touch synchronization signal according to the first embodiment of the present disclosure when the display refresh rate is the first frequency;

[0020] Figure 8 This is a diagram illustrating the timing of the second touch synchronization signal according to the second embodiment of the present disclosure when the display refresh rate changes from a first frequency to a second frequency;

[0021] Figure 9 This is a diagram illustrating the timing of the second touch synchronization signal according to the third embodiment of this disclosure when the display refresh rate changes from a first frequency to a second frequency;

[0022] Figure 10 This is a diagram showing the timing of the second touch synchronization signal according to the fourth embodiment of this disclosure when the display refresh rate changes from a first frequency to a second frequency;

[0023] Figure 11 This is a diagram illustrating the timing of the second touch synchronization signal according to the fifth embodiment of this disclosure when the display refresh rate changes from a first frequency to a second frequency; and

[0024] Figure 12 This is a diagram showing the timing of the second touch synchronization signal according to the sixth embodiment of this disclosure when the display refresh rate changes from a first frequency to a second frequency. Detailed Implementation

[0025] The advantages and features of this disclosure and its implementation methods will be illustrated by the following exemplary embodiments described with reference to the accompanying drawings. However, this disclosure may be embodied in various forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. Furthermore, this disclosure is limited only by the scope of the claims.

[0026] Throughout this disclosure, the same reference numerals denote substantially the same elements. In the following description, detailed descriptions of relevant known functions or configurations will be omitted where it is determined that such descriptions would unnecessarily obscure the essence of this disclosure. Furthermore, the element names used in the following description are illustrative and may differ from the names of the actual products corresponding to those elements.

[0027] In the context of the use of “comprising,” “having,” and “including” as described in this disclosure, an additional part may be added. Unless otherwise stated, singular terms may include plural forms.

[0028] When interpreting components, even if not explicitly described, the components are interpreted as including a range of error.

[0029] It will be understood that although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. Therefore, without departing from the scope of this disclosure, the first element referred to below may be called the second element.

[0030] The term "at least one" should be understood to include any and all combinations of one or more of the related listed items. For example, "at least one of the first, second, and third items" means each of the first, second, and third items, as well as all combinations of two or more items derived from the first, second, and third items.

[0031] Those skilled in the art will fully understand that the features of the various exemplary embodiments of this disclosure may be partially or wholly linked or combined with each other, and may interoperate or be combined and technically driven with each other in various ways. The exemplary embodiments of this disclosure may be implemented independently of each other, or may be implemented together in a mutually dependent manner.

[0032] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0033] Figure 1 This is a block diagram of a touch display system including a touch display driving device according to one embodiment of the present disclosure. Figure 1 The touch display system 100 shown performs display and touch scanning (or touch sensing) in a time-division manner. Although the components for display and the components for touch scanning can be shared in an embedded manner, this embodiment is not limited to a time-division method or an embedded method. For example, the touch display driver device of the following embodiment can also be implemented according to an external method or an embedded method of the overlay surface method.

[0034] According to various embodiments, the display and touch scanning of the touch display driving device can be implemented as separate operations. Here, display means representing a desired image by driving pixels on the display panel, and touch scanning means identifying the touch position on the display panel. Furthermore, the time-division method means that display and touch recognition are performed sequentially in an alternating manner according to the time domain. In one embodiment, touch scanning can be performed during a vertical blank period within a frame time period.

[0035] An embedded method refers to an implementation that enables simultaneous display and touch scanning of pixels in a display panel. For this purpose, a shared component capable of providing capacitance for touch scanning can be used, and at least connection points of the component may be included. Examples of connection points could be nodes (COM) that apply a common voltage, but are not limited to this; various components may be used as connection points depending on the manufacturer's intent.

[0036] Furthermore, the touch display system 100 according to this disclosure can be used in smartphones, tablet computers, laptops, etc., and can provide a thin and lightweight design while achieving high-definition images. According to an embodiment, the touch display system 100 according to this disclosure can be a vertical blanking (VBS) system.

[0037] The touch display system 100 disclosed herein can operate in a default mode with a fixed frequency and in a variable refresh rate (VRR) mode that varies between multiple frequencies depending on the type of image data Idata input from the host. The variable refresh rate mode can be primarily used to prevent screen tearing or stuttering in tasks with inconsistent graphics loads, such as gaming and video playback.

[0038] In one embodiment, the touch display system 100 according to embodiments of the present disclosure can display general image data, such as TV images, at a fixed frequency in a default mode, and display special image data, such as game images or movies, at varying frequencies in a variable refresh rate mode. However, the image data output in the default mode and the image data output in the variable refresh rate mode can be changed in various ways, and the image data mentioned herein correspond to some examples.

[0039] Besides the default mode and variable refresh rate mode, operating modes that are distinguished by whether the frequency of the displayed image data changes can be represented by various terms.

[0040] Furthermore, when the touch display system 100 of this disclosure changes from the default mode to the variable refresh rate mode, a horizontal time interval (1H) is fixed to the same value to display a stable image, and the length of one frame (1 frame) can be adjusted by changing the vertical blank time interval Vblank. In this case, the vertical blank time interval before the change is described as vertical blank, and the vertical blank time interval increased due to the change in the vertical blank time interval is described as dummy blank time interval.

[0041] According to one embodiment of the present disclosure, a touch display system 100 performs display functions and touch scanning functions, and can be implemented as a flat panel display such as a liquid crystal display (LCD) or an organic light-emitting diode display (OLED).

[0042] like Figure 1 As shown, a touch display system 100 according to one embodiment of this disclosure includes a touch display driver 110 and a panel 120 (hereinafter, described as a concept including a touch screen and a display panel). The touch display driver 110 may include a timing controller 210, a gate driver 220, a data driver 230, a touch driver 235, and a touch microcontroller unit 240. Although Figure 1 The touch microcontroller unit 240 and the touch driver 235 are shown as separate components, but the touch driver 235 and the touch microcontroller unit 240 can be implemented as a single chip.

[0043] Panel 120 displays a specific grayscale image or receives touch input from a hand (or finger) or a stylus (or electronic pen). Multiple data lines D1 to Dn connected to data driver 230 and multiple gate lines G1 to Gm connected to gate driver 220 may be formed on panel 120. For example, the multiple data lines D1 to Dn may be arranged in rows or columns, and the multiple gate lines G1 to Gm may be arranged in columns or rows. In the following description, for ease of description, it is assumed that the multiple data lines D1 to Dn are arranged in rows and the multiple gate lines G1 to Gm are arranged in columns.

[0044] Furthermore, multiple pixels P can be defined at the intersection of multiple data lines D1 to Dn and multiple gate lines G1 to Gm.

[0045] Each pixel P can be composed of red (R), green (G), blue (B), and white (W) sub-pixels. In one embodiment, the sub-pixels can be repeatedly formed in the row direction, or they can be formed in a 2*2 matrix form. In this case, a color filter corresponding to each color is provided in each of the red (R), green (G), and blue (B) sub-pixels, while no separate color filter is provided in the white (W) sub-pixels. In one embodiment, the red (R), green (G), blue (B), and white (W) sub-pixels can be formed with the same area ratio, but the red (R), green (G), blue (B), and white (W) sub-pixels can also be formed with different area ratios.

[0046] Each of the multiple pixels P can be a liquid crystal display (LCD) pixel or an organic light-emitting diode (OLED) pixel, but is not limited thereto.

[0047] In one embodiment, panel 120 may be a panel with an embedded touch-type structure using a capacitive method. According to the embodiment, components for display and components for touch scanning may be shared in an embedded manner. For example, a touch electrode TE for detecting touches on a touchscreen may be used as a common voltage electrode to supply a common voltage from the display panel to it. Although embedded panels are known to be an integrated form of a display panel and a touchscreen combination, this is merely an example of the panel 120 described above, and panels applying this disclosure are not limited to embedded panels.

[0048] In one embodiment, panel 120 may be an embedded touch panel using a self-capacitance method or an embedded touch panel using a mutual capacitance method.

[0049] In the following text, refer to Figure 2 and Figure 3 The following will describe in more detail the in-wall touch panel using the mutual capacitance method and the in-wall touch panel using the self-capacitance method.

[0050] Figure 2 This is a schematic diagram illustrating an example of an embedded touch panel using the mutual capacitance method.

[0051] like Figure 2 As shown, panel 120 includes touch driving lines TX1 to TXm (m is a natural number greater than or equal to 2), a plurality of touch electrodes TE, and touch sensing lines RX1 to RXn (n is a natural number greater than or equal to 2).

[0052] Touch drive lines TX1 to TXm transmit touch drive signals to each touch electrode TE. Each touch electrode TE may include mutual capacitors. Touch sensing lines RX1 to RXn transmit the voltage (or charge) of each touch electrode TE to the touch driver 235.

[0053] The touch sensing lines RX1 to RXn can refer to the sensing lines of panel 120, or they can also be called touch sensing channels.

[0054] Figure 3 This diagram schematically illustrates an example of an embedded touch panel using a self-capacitance method. In the self-capacitance touch method, which is another type of capacitive touch method, the supply of the touch drive signal and the reception of the capacitance generated by the user's touch or the touch of a stylus are achieved through one of the touch lines T1 to Tk.

[0055] In this self-capacitance touch method, the value sensed at the corresponding touch electrode (TE) changes according to the touch or proximity of an object such as a finger or pen, and the self-capacitance touch method can use the sensed value to detect the presence or absence of a touch, touch coordinates, etc.

[0056] Refer to Figure 1 Panel 120 can operate in display driving mode and touch scanning mode. Panel 120 can display images during display driving mode and be used as a touch panel for touch scanning during touch scanning mode.

[0057] The timing controller 210 controls the operation of the data driver 230, the gate driver 220, the touch driver 235, and the touch microcontroller unit 240 to enable display and touch scanning to be performed in a time-division manner.

[0058] The timing controller 210 starts scanning according to the timing implemented in each frame, converts the externally input image data Idata into the data signal format used by the data driver 230, outputs the converted image data (R / G / B), and drives the scan control data according to the timing.

[0059] The timing controller 210 controls the data driver 230 and the gate driver 220 for display. The timing controller 210 can control the data driver 230 and the gate driver 220 by supplying various control signals DCS and GCS required for the driving operation of the data driver 230 and the gate driver 220.

[0060] The timing controller 210 receives various timing signals TS from an external source (e.g., a host system) along with image data (R / G / B), including vertical synchronization signal Vsync, horizontal synchronization signal Hsync, input data enable (DE) signal, clock signal CLK, etc.

[0061] The timing controller 210 converts externally input image data Idata into the data signal format used by the data driver 230 and outputs the converted image data (R / G / B). In addition, in order to control the data driver 230 and the gate driver 220, the timing controller 210 receives timing signals TS such as vertical synchronization signal Vsync, horizontal synchronization signal Hsync, input data enable (DE) signal, clock signal CLK, etc., generates various control signals, and outputs various control signals to the data driver 230 and the gate driver 220.

[0062] The timing controller 210 can be implemented as a component separate from the data driver 230, or it can be integrated with the data driver 230 and implemented as an integrated circuit.

[0063] The timing controller 210 generates a touch synchronization signal Tsync and sends it to the touch driver 235 and the touch microcontroller unit 240 to control touch operations. The touch synchronization signal Tsync defines the display driving period for displaying the image and the touch scanning period for performing the touch scan. In one embodiment, the period during which the touch synchronization signal Tsync is maintained at a first level (e.g., low level L) can be defined as the touch scanning period TST, and the period during which the touch synchronization signal Tsync is maintained at a second level (e.g., high level H) can be defined as the display driving period DDT.

[0064] In particular, according to this disclosure, the timing controller 210 can selectively generate either a first touch synchronization signal Tsync1 or a second touch synchronization signal Tsync2 based on the operating mode of the touch display system 100. Specifically, when the touch display system 100 operates in a default mode with a display refresh rate DRR of a first frequency (e.g., 120Hz), the timing controller 210 can generate the first touch synchronization signal Tsync1; when the touch display system 100 operates in a variable refresh rate mode where the display refresh rate decreases from the first frequency to a second frequency (e.g., 119Hz, 60Hz, 30Hz, 20Hz, etc.), the second touch synchronization signal Tsync2 is generated.

[0065] According to an implementation, the first touch synchronization signal Tsync1 may include a first touch scan period TST1 and a display drive period DDT. In addition to the first touch scan period TST1 and the display drive period DDT, the second touch synchronization signal Tsync2 may also include a second touch scan period TST2 and a dummy blank period DBLANK. In this case, as described above, the dummy blank period DBLANK refers to a vertical blank period added before the display refresh rate changes to stably display the image.

[0066] Since when the touch display system 100 operates in variable refresh rate mode, the timing controller 210 of this disclosure generates a second touch synchronization signal Tsync2 that includes a second touch scan period TST2, and touch coordinates can be generated by performing a touch scan during the second touch scan period TST2, the touch report rate can be maintained at the first frequency as in the default mode even when the display report rate decreases from the first frequency to the second frequency.

[0067] Furthermore, the timing controller 210 according to this disclosure may also include a leading period PA that is maintained at the second level for a predetermined period of time before the first touch scan period TST1 or the second touch scan period TST2 included in the first touch synchronization signal Tsync1 or the second touch synchronization signal Tsync2.

[0068] To generate the first touch synchronization signal Tsync1 and the second touch synchronization signal Tsync2 mentioned above, the timing controller 210 may include a detection circuit 212 and a touch synchronization signal generation circuit 214, such as... Figure 4 As shown. Although in Figure 4 The detection circuit 212 and the touch synchronization signal generation circuit 214 are shown as hardware configurations, but the detection circuit 212 and the touch synchronization signal generation circuit 214 can also be implemented in software form as executed by the timing controller 210.

[0069] also, Figure 4 The diagram only shows the configuration required to generate the touch synchronization signal; the timing controller 210 may also include other configurations for controlling the gate driver 220 and the data driver 230.

[0070] The detection circuit 212 detects the display refresh rate based on the vertical synchronization signal Vsync and generates a detection signal DET. In one embodiment, the detection signal DET may include at least one of information about a display refresh rate having a first frequency or information about a display refresh rate having a second frequency, which may be processed by the touch synchronization signal generation circuit 214.

[0071] In addition, in order to determine whether the leading period PA is included, the detection circuit 212 can calculate the difference between the first frequency and the second frequency and send the calculation result to the touch synchronization signal generation circuit 214.

[0072] The touch synchronization signal generation circuit 214 generates a touch synchronization signal Tsync based on the detection signal DET. Specifically, when the display refresh rate is determined to be a first frequency based on the detection signal DET, the touch synchronization signal generation circuit 214 generates a first touch synchronization signal Tsync1, and when the display refresh rate is determined to decrease from the first frequency to the second frequency, a second touch synchronization signal Tsync2 is generated.

[0073] The touch synchronization signal generation circuit 214 generates a second touch synchronization signal Tsync2, which is different from the first touch synchronization signal Tsync1, based on the detection signal DET, so that the touch report rate can be maintained at the first frequency even when the display refresh rate decreases from the first frequency to the second frequency.

[0074] like Figures 5 to 12As shown, the first touch synchronization signal Tsync1 sequentially includes a first touch scan period TST1 and a display drive period DDT, and the second touch synchronization signal Tsync2 sequentially includes the first touch scan period TST1, the display drive period DDT, the second touch scan period TST2, and a dummy blank period DBLANK. In this case, the first touch scan period TST1 and the second touch scan period TST2 can refer to periods corresponding to or synchronized with the vertical blank period, and the dummy blank period DBLANK can correspond to the period when the image is displayed at a first frequency. During the vertical blank period (e.g., the period corresponding to the first touch scan period TST1 and the second touch scan period TST2) and the dummy blank period DBLANK, the previously displayed image can be maintained.

[0075] Available Figure 5 and Figure 7 As seen in the diagram, during the first touch scan period TST1, the first touch synchronization signal Tsync1 can be at a first level (e.g., low level), and the display drive period DDT can be at a second level (e.g., high level). Furthermore, it is possible to... Figure 6 and Figures 8 to 12 As seen in the diagram, during the first touch scan period TST1 and the second touch scan period TST2, the second touch synchronization signal Tsync2 may be at a first level (e.g., low level), and the display drive period DDT and the dummy blank period DBLANK may be at a second level (e.g., high level).

[0076] In addition, such as Figures 7 to 12 As shown, the second touch synchronization signal Tsync2 may also include a leading period PA that remains at the second level for a predetermined time period before the first touch scan period TST1 and the second touch scan period TST2. Although Figures 7 to 12 The second touch synchronization signal Tsync1 is shown to always include a leading period PA, but this is only an example; the leading period PA may be optionally included in the second touch synchronization signal Tsync2.

[0077] In one embodiment, when the difference between the first frequency and the second frequency is less than or equal to a reference value, the preamble period PA may be included in the second touch synchronization signal Tsync2. In this disclosure, the preamble period PA is included in the second touch synchronization signal Tsync2 when the difference between the first frequency and the second frequency is less than or equal to the reference value because when the difference between the first frequency and the second frequency is small, the dummy blank period DBLANK is set to be very short, so the second touch scan period TST2 of the current frame and the first touch scan period TST1 of the next frame may not be distinguishable.

[0078] For example, when the display refresh rate changes from 120Hz to 119Hz, the dummy blank period DBLANK is set to be very short because the difference between the first frequency and the second frequency is small. Therefore, the touch synchronization signal generation circuit 214 includes a preamble period PA before the first touch scan period TST1 and the second touch scan period TST2 to distinguish the second touch scan period TST2 of the current frame from the first touch scan period TST1 of the next frame.

[0079] In another example, when the display refresh rate changes from 120Hz to 60Hz or from 120Hz to 30Hz, the dummy blank period DBLANK can be set to a sufficient length because the difference between the first and second frequencies is large. Therefore, since the second touch scan period TST2 of the current frame and the first touch scan period TST1 of the next frame are clearly distinguishable due to the dummy blank period DBLANK, the touch synchronization signal generation circuit 214 can exclude the preamble period PA from the second touch synchronization signal Tsync2.

[0080] The leading period PA can be shorter than the first touch scan period TST1 and the second touch scan period TST2, and the first touch scan period TST1 and the second touch scan period TST2 can be shorter than the display driving period DDT.

[0081] Furthermore, during the lead time PA, the image corresponding to the new image data is not output, and the image of the previous frame being output to panel 120 can be maintained.

[0082] The touch synchronization signal generation circuit 214 can send a first touch synchronization signal Tsync1 and a second touch synchronization signal Tsync2 to the touch microcontroller unit 240 or the touch driver 235.

[0083] In one embodiment, the touch synchronization signal generation circuit 214 can send a first touch synchronization signal Tsync1 and a second touch synchronization signal Tsync2 via a general-purpose input / output (GPIO) pin. According to the embodiment, at least one of the timing controller 210, the touch driver 235, and the touch microcontroller unit 240 may include a GPIO pin for sending or receiving the first touch synchronization signal Tsync1 and the second touch synchronization signal Tsync2.

[0084] Refer to Figure 1 Gate driver 220 supplies scan signals to gate lines G1 to Gm to turn switches (e.g., transistors) located at each pixel P on and off. Depending on the driving method, gate driver 220 may be configured as follows: Figure 1 The image shown is located only on one side of panel 120, or it can be divided into two and located on both sides of panel 120.

[0085] Gate driver 220 may include at least one gate driver integrated circuit. The at least one gate driver integrated circuit may be connected to bonding pads of panel 120 using a tape-on-board (TAB) method or a chip-on-glass (COG) method, or may be implemented as a gate-in-panel (GIP) type and formed directly on panel 120, and in some cases, may be formed by integration into panel 120. Furthermore, gate driver 220 may be implemented using a chip-on-film (COF) method.

[0086] Gate driver 220 can receive a gate control signal GCS, generate a gate drive signal corresponding to the gate control signal GCS, and provide the gate drive signal to pixel P of panel 120. According to one embodiment, gate driver 220 may include an input buffer, a shift register, a level shifter, and an output buffer. The input buffer can receive the gate control signal GCS and output the gate control signal GCS to the shift register, and the shift register can control the sequential generation of scan pulses as gate signals sent through the input buffer, column by column, of panel 120. The level shifter has the function of changing the output voltage level of the shift register to a level that enables thin-film transistors (TFTs) configured as switches to be turned on and off, and the output buffer can change the signal output from the level shifter and output the signal as a gate drive signal capable of driving gate lines G1 to Gm with RC loads.

[0087] Data driver 230 supplies data voltage to data line DL to display images on individual pixels P of panel 120. Data driver 230 may include at least one source driver integrated circuit (SDIC). At least one SDIC may be connected to bonding pads of panel 120 using tape auto-bonding (TAB) or chip-on-glass (COG) methods, or may be formed directly on panel 120, and in some cases, may be formed by integration into panel 120. Furthermore, data driver 230 may be implemented using chip-on-film (COF) methods.

[0088] At least one SDIC can be configured to generate a source drive signal based on the data control signal (DCS) and provide the source drive signal to the pixel P of the panel 120. The SDIC typically includes a latch, a digital-to-analog converter (DAC), and an output buffer. Here, the latch stores image data according to the display control signal and provides the image data to the DAC, and the DAC can output an analog signal of the voltage corresponding to the input image data. The output buffer can transmit the output of the DAC as a source drive signal to the pixel P of the panel 120 via data lines D1 to Dn.

[0089] In one embodiment, when the touch display system 100 operates in default mode with a display refresh rate of a first frequency, the SDIC displays an image corresponding to the image data (R / G / B) input from the timing controller 210 during the display drive period DDT when the first touch synchronization signal Tsync1 is at a second level (high level) within a one-frame time period. During the first touch scan period TST1 when the first touch synchronization signal Tsync1 is at a first level (low level) within a one-frame time period, the SDIC maintains the image output in the previous frame.

[0090] Subsequently, when the touch display system 100 operates in a variable refresh rate mode where the display refresh rate is reduced to a second frequency, the SDIC displays an image corresponding to the image data (R / G / B) input from the timing controller 210 during the display drive period DDT when the second touch synchronization signal Tsync2 is at the second level (high level) within a one-frame period. During the prelude period PA and the dummy blank period DBLANK when the second touch synchronization signal Tsync2 is at the second level (high level) within a one-frame period, the SDIC maintains the image output in the previous frame. Furthermore, during the first touch scan period TST1 and the second touch scan period TST2 when the second touch synchronization signal Tsync2 is at the first level (low level) within a one-frame period, the SDIC maintains the image output in the previous period.

[0091] The touch driver 235 processes response signals (e.g., performs analog-to-digital conversion) output from the plurality of touch electrodes TE included in the panel 120 during the first touch scan period TST1 and the second touch scan period TST2 based on the control signal CTL sent from the touch microcontroller unit 240 to generate touch raw data RawD. The touch driver 235 sends the generated touch raw data RawD to the touch microcontroller unit 240.

[0092] The touch microcontroller unit 240 can generate a control signal CTL for controlling the operation of the touch driver 235 based on the first touch synchronization signal Tsync1 and the second touch synchronization signal Tsync2. Furthermore, the touch microcontroller unit 240 can use the raw touch data RawD sent from the touch driver 235 to calculate the touch coordinates RTC and send the calculated touch coordinates RTC to the host according to the touch report rate.

[0093] In one embodiment, regardless of changes in the display refresh rate, the touch microcontroller unit 240 according to this disclosure can send the touch coordinate RTC to the host based on a constant touch report rate. That is, when the display refresh rate is a first frequency, the touch microcontroller unit 240 sends the touch coordinate RTC to the host based on a touch report rate based on the first frequency. Furthermore, even when the display refresh rate changes from the first frequency to a second frequency, since the touch driver 235 performs touch scanning according to the first frequency, the touch microcontroller unit 240 can still send the touch coordinate RTC to the host based on a touch report rate based on the first frequency.

[0094] In the following text, refer to Figures 5 to 12 This section will describe the waveform of the touch synchronization signal and an example of the touch report rate as the display refresh rate changes.

[0095] Figure 5 This diagram illustrates the timing of the touch synchronization signal when the display refresh rate is at its first frequency. Figure 6 This is a diagram illustrating the timing of the touch synchronization signal when the display refresh rate changes from a first frequency to a second frequency. Figure 5 In this context, assuming the first frequency is 120Hz, Figure 6 In this context, we assume the second frequency is 60Hz.

[0096] Reference Figure 5 and Figure 6 In a typical embedded touch display system, since display and touch scanning can be performed simultaneously on pixels within the panel 120, the first touch scan period TST1 and the display drive period DDT are divided and operated at a specific ratio within one frame. Therefore, the first touch synchronization signal Tsync1 includes the first touch scan period TST1 maintained at a first level and the display drive period DDT maintained at a second level.

[0097] like Figure 6 As shown, when the display refresh rate decreases from the first frequency to the second frequency, the second touch synchronization signal Tsync2 also includes a dummy blanking period DBLANK maintained at the second level (high level) to replace the first touch scan period TST1 and the display drive period DDT that output the image according to the first frequency. Therefore, as the drive frequency of the first touch scan period TST1 decreases from the first frequency to the second frequency, the touch report rate also decreases from the first frequency to the second frequency.

[0098] Therefore, in order to solve the above problems, such as Figure 8 and Figure 9As shown, the touch display system 200 according to this disclosure can generate a second touch synchronization signal Tsync2, which includes a second touch scan period TST2 maintained at the first level in addition to a first touch scan period TST1 maintained at the first level, so that even when the display refresh rate decreases from the first frequency to the second frequency, the touch report rate can be maintained at the first frequency.

[0099] Figure 7 This is a diagram illustrating the timing of the first touch synchronization signal according to the first embodiment of the present disclosure when the display refresh rate is the first frequency.

[0100] exist Figure 7 In, with Figure 5 Unlike other signals, the first touch synchronization signal Tsync1 generated by the touch synchronization signal generation circuit 214 may include a leading period PA maintained at the second level before the first touch scan period TST1 maintained at the first level. As described above, when the dummy blank period DBLANK is set to a shorter value, a leading period PA is provided to distinguish the first touch scan period TST1 from the second touch scan period TST2, but if... Figure 7 As shown, the first touch synchronization signal Tsync1 may include a preamble period PA maintained at a second level before the first touch scan period TST1. According to the first embodiment, the touch driver 235 can maintain the touch scan period at a constant level regardless of the display frame rate, thereby enhancing the ease of touch control.

[0101] In addition, such as Figure 7 As shown, the touch microcontroller unit 240 can generate a control signal CTL that enables the operation of the touch electrode TE of the control panel 120 during the first touch scan period TST1 included in the first touch synchronization signal Tsync1, and output the control signal CTL to the touch driver 235. The touch driver 235 can use the response signal corresponding to the user's touch on the touch electrode TE to generate touch raw data RawD and output the touch raw data RawD to the touch microcontroller unit 240.

[0102] The touch microcontroller unit 240 can generate touch coordinate RTC based on the raw touch data RawD and send the touch coordinate RTC to the host according to the touch report rate with a first frequency.

[0103] Reference Figure 7 The processing time PT is the time when the touch driver 235 generates the raw touch data RawD or the time when the touch microcontroller unit 240 calculates the touch coordinates RTC. The touch microcontroller unit 240 reports the touch coordinates RTC to the host at each time point of the elapsed processing time PT after the end of the first touch scan period TST1, according to the touch report rate with a first frequency.

[0104] Figure 8 This is a diagram illustrating the timing of the second touch synchronization signal according to a second embodiment of the present disclosure when the display refresh rate changes from a first frequency to a second frequency. Figure 8 In this context, we assume the first frequency is 120Hz and the second frequency is 60Hz.

[0105] like Figure 8 As shown, when the display refresh rate decreases from 120Hz to 60Hz, the touch synchronization signal generation circuit 214 generates a second touch synchronization signal Tsync2. The second touch synchronization signal Tsync2 includes a preamble period PA with a second level (high level), a first touch scan period TST1 with a first level (low level), a display drive period DDT with a second level (high level), a preamble period PA with a second level (high level), a second touch scan period TST2 with a first level (low level), and a dummy blank period DBLANK with a second level (high level).

[0106] Therefore, the touch driver 235 performs a touch scan during the first touch scan period TST1 and the second touch scan period TST2 to generate raw touch data (RawD), and the touch microcontroller unit 240 generates touch coordinates (RTC) based on the raw touch data and outputs the touch coordinates RTC to the host. In this case, since the touch scan is performed during the first touch scan period TST1 and the second touch scan period TST2 to generate touch coordinates, the touch microcontroller unit 240 can output the touch coordinates RTC to the host according to a touch report rate of 120Hz.

[0107] exist Figure 8 The image shows the second touch synchronization signal Tsync2 including a preamble period PA, but this is just an example. Since the difference between the first frequency and the second frequency is large (i.e., 60Hz), the preamble period PA can be omitted.

[0108] Figure 9 This is a diagram illustrating the timing of the second touch synchronization signal according to a third embodiment of the present disclosure when the display refresh rate changes from a first frequency to a second frequency. Figure 9 In this context, we assume the first frequency is 120Hz and the second frequency is 30Hz.

[0109] like Figure 9As shown, when the display refresh rate decreases from 120Hz to 30Hz, the touch synchronization signal generation circuit 214 generates a second touch synchronization signal Tsync2. The second touch synchronization signal Tsync2 includes a preamble period PA with a second level (high level), a first touch scan period TST1 with a first level (low level), a display drive period DDT with a second level (high level), a preamble period PA with a second level (high level), multiple second touch scan periods TST2 with a first level (low level), and a dummy blank period DBLANK with a second level (high level).

[0110] That is, in Figure 9 In the example shown, since the second touch synchronization signal according to the third embodiment of this disclosure includes three second touch scan periods TST2 within a dummy blank period DBLANK, the touch report rate can be maintained regardless of changes in the display frame rate.

[0111] Specifically, the touch driver 235 performs a touch scan during the first touch scan period TST1 and the second touch scan period TST2 to generate raw touch data (RawD), and the touch microcontroller unit 240 generates touch coordinates (RTC) based on the raw touch data and outputs the touch coordinates RTC to the host. In this case, since the touch scan can be performed during the first touch scan period TST1 and the second touch scan period TST2 to generate touch coordinates, the touch microcontroller unit 240 can output the touch coordinates RTC to the host according to a touch report rate of 120Hz.

[0112] exist Figure 9 The image shows the second touch synchronization signal Tsync2 including a preamble period PA, but this is just an example. Since the difference between the first frequency and the second frequency is large (i.e., 90Hz), the preamble period PA can be omitted.

[0113] Figure 10 This is a diagram illustrating the timing of the second touch synchronization signal according to the fourth embodiment of this disclosure when the display refresh rate changes from a first frequency to a second frequency. Figure 11 This is a diagram illustrating the timing of the second touch synchronization signal according to the fifth embodiment of this disclosure when the display refresh rate changes from a first frequency to a second frequency. Figure 12 This is a diagram illustrating the timing of the second touch synchronization signal according to the sixth embodiment of this disclosure when the display refresh rate changes from a first frequency to a second frequency. Figures 10 to 12 In this context, we assume the first frequency is 120Hz and the second frequency is a frequency within the range of less than 120Hz and greater than 120Hz - (1 / Tμs). In this case, Tμs refers to a predetermined margin period.

[0114] Reference Figure 10 Since the difference between the first frequency and the second frequency is very small, the dummy blank period DBLANK is set to be very short, and the margin period Tμs is set to be shorter than the first touch scan period TST1. That is, the touch synchronization signal generation circuit 214 generates a second touch synchronization signal Tsync2, which includes the first touch scan period TST1 maintained at the first level, the display drive period DDT maintained at the second level, the margin period Tμs maintained at the first level, and the dummy blank period DBLANK that transitions to the second level in a very short time.

[0115] exist Figure 10 In this case, because the margin period Tμs is set to be shorter than the first touch scan period TST1, the touch driver 235 cannot perform touch scans on all touch electrodes TE included in the panel 120 during the margin period Tμs. However, because the dummy blank period DBLANK is set to be very short, the touch microcontroller unit 240 reports the touch coordinate RTC according to the touch report rate with a second frequency, but since the difference between the first frequency and the second frequency is not large, the degradation of touch performance may not be significant.

[0116] However, in Figure 10 In this case, because the dummy blank period DBLANK is set to be very short, the touch driver 235 may not be able to accurately recognize the first touch scan period TST1 of the next frame.

[0117] Therefore, in order to solve this problem, such as Figure 11 As shown, the touch synchronization signal generation circuit 214 generates a second touch synchronization signal Tsync2. The second touch synchronization signal Tsync2 includes a preamble period PA with a second level (high level), a first touch scan period TST1 with a first level (low level), a display drive period DDT with a second level (high level), a preamble period PA with a second level (high level), a margin period Tμs with a first level (low level), and a dummy blank period DBLANK that transitions to the second level in a very short time.

[0118] Therefore, the touch microcontroller unit 240 can report the touch coordinate RTC according to the touch report rate with a second frequency. In addition, the touch driver 235 can accurately identify the first touch scan period TST1 of the next frame through the preamble period PA.

[0119] In addition, Figure 10 and Figure 11In this case, because the margin period Tμs is set shorter than the first touch scan period TST1, the touch driver 235 may not be able to perform a touch scan for all touch electrodes TE included in the panel 120 during the margin period Tμs. However, as Figure 12 As shown, when the margin period Tμs is set to be longer than or equal to the length of the first touch scan period TST1, the touch driver 235 can perform touch scanning even during the margin period Tμs. According to an embodiment, the margin period Tμs can be operated as the second touch scan period TST2.

[0120] Specifically, refer to Figure 12 Since the difference between the first frequency and the second frequency is very small, the dummy blank period DBLANK is set to be very short, and the margin period Tμs is set to be longer than or equal to the first touch scan period TST1. That is, the touch synchronization signal generation circuit 214 generates a second touch synchronization signal Tsync2, which includes a preamble period PA with a second level (high level), a first touch scan period TST1 with a first level (low level), a display drive period DDT with a second level (high level), a preamble period PA with a second level (high level), a margin period Tμs (or the second touch scan period TST2) with a first level (low level), and a dummy blank period DBLANK that transitions to the second level in a very short time.

[0121] In this scenario, a delay time Td may occur when the touch microcontroller unit 240 calculates the touch coordinates RTC for each of the first touch scan periods TST1. The delay time Td can be a concept included in the processing time PT.

[0122] exist Figure 12 Since the margin period Tμs is set to be longer than or equal to the first touch scan period TST1, the touch driver 235 can perform touch scans on all touch electrodes TE included in the panel 120 during the margin period Tμs. Therefore, the touch microcontroller unit 240 can report the touch coordinate RTC according to a touch reporting rate having a frequency twice that of the second frequency.

[0123] In addition, the touch driver 235 can also accurately identify the first touch scan period TST1 of the next frame through the leading period PA.

[0124] According to this disclosure, since a touch synchronization signal that allows additional touch scanning to be added when the display refresh rate changes is generated, there is an effect that the touch report rate can be maintained at a constant level even in a variable refresh rate mode where the display refresh rate changes.

[0125] Furthermore, according to this disclosure, since a touch synchronization signal including a leading period distinct from the touch scanning period is generated, the touch report rate can be stably maintained even when the display refresh rate changes very little, thus enhancing touch sensing performance.

[0126] It will be apparent to those skilled in the art that various modifications and variations can be made to this disclosure without departing from the spirit or scope thereof. Therefore, this disclosure is intended to cover such modifications and variations.

[0127] The various embodiments described above can be combined to provide further embodiments. Based on the above description, these and other changes can be made to the embodiments. Generally, the terminology used in the following claims should not be construed as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be interpreted to include all possible embodiments and the full scope of equivalents enjoyed by these claims. Therefore, these claims are not limited by this disclosure.

[0128] Cross-references to related applications

[0129] This application claims the benefit of Korean Patent Application No. 10-2025-0003748, filed on January 9, 2025, which is incorporated herein by reference as fully set forth herein.

Claims

1. A touch display driving device, the touch display driving device comprising: A timing controller generates a first touch synchronization signal including a first touch scan period and a display drive period when operating in a default mode with a display refresh rate of a first frequency, and generates a second touch synchronization signal including the first touch scan period, the display drive period, the second touch scan period, and a dummy blank period when operating in a variable refresh rate mode where the display refresh rate decreases from the first frequency to the second frequency. A touch driver that performs a touch scan during the first touch scan period and the second touch scan period to generate raw touch data; as well as A touch microcontroller unit that generates touch coordinates based on the raw touch data and reports the generated touch coordinates according to the touch reporting rate.

2. The touch display driving device according to claim 1, wherein, The timing controller includes: A detection circuit that detects changes in the display refresh rate based on a vertical synchronization signal and generates a detection signal; and A touch synchronization signal generation circuit generates the first touch synchronization signal and the second touch synchronization signal based on the detection signal.

3. The touch display driving device according to claim 1, wherein, The first touch scanning period is the period during which the first touch synchronization signal and the second touch synchronization signal are maintained at a first level. The display driving period is the period during which the first touch synchronization signal and the second touch synchronization signal are maintained at a second level different from the first level. The second touch scanning period is the period during which the second touch synchronization signal remains at the first level, and The dummy blank period is the period during which the second touch synchronization signal remains at the second level.

4. The touch display driving device according to claim 3, wherein, When operating in the variable refresh rate mode, the timing controller generates a second touch synchronization signal that includes a preamble period maintained at the second level for a predetermined time before the first touch scan period and the second touch scan period.

5. The touch display driving device according to claim 4, wherein, When the difference between the first frequency and the second frequency is less than or equal to a reference value, the timing controller includes the preamble period in the second touch synchronization signal.

6. The touch display driving device according to claim 4, wherein, The leading period is set to be shorter than the first touch scan period and the second touch scan period.

7. The touch display driving device according to claim 1, wherein, In both the default mode and the variable refresh rate mode, the touch report rate remains at the first frequency.

8. The touch display driving device according to claim 1, further comprising a data driver that outputs an image based on image data received from the timing controller during the display driving period, and maintains the previously output image during the first touch scan period, the second touch scan period, and the dummy blank period.

9. The touch display driving device according to claim 8, wherein, The touch driver and the data driver are implemented as a single chip.

10. The touch display driving device according to claim 1, wherein, The touch driver generates the raw touch data for each of the first touch scan period and the second touch scan period based on response signals output from a plurality of touch electrodes included in the embedded panel.

Images