Source output voltage compensation for display noise

Abstract

To provide an input-display device that reduces noise, a touch display driver integrated (TDDI) circuit, and a method for driving a display of the input-display device.SOLUTION: An input-display device includes a display screen disposed on a display substrate, the display screen including a multitude of display pixels. The input-display device further includes a multitude of capacitive sensing electrodes for capacitive sensing in a sensing region of the display screen. The input-display device also includes a source driver circuit configured to generate a data voltage for driving a pixel circuit associated with one display pixel of the multitude of display pixels and determine a timing for a compensatory modulation of the data voltage. The timing for the compensatory modulation of the data voltage is determined using a sensing waveform of the capacitive sensing. The source driver circuit is also configured to determine an amplitude of the compensatory modulation, generate a modulated data voltage by applying the compensatory modulation to the data voltage, and drive the pixel circuit using the modulated data voltage.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This application claims the benefit of U.S. Patent Law § 119(e) to U.S. Provisional Patent Application No. 63 / 125,344, filed December 14, 2020. U.S. Provisional Patent Application No. 63 / 125,344 is hereby incorporated by reference in its entirety.

[0002] The described embodiments relate generally to electronic devices, and more specifically, to noise reduction in input display devices.

Background Art

[0003] Input devices that include proximity sensor devices (e.g., touch pads or touch sensor devices) are widely used in various electronic systems. Proximity sensor devices typically include a sensing region that is often demarcated on a surface, in which the proximity sensor device detects the presence, position, and / or movement of one or more input objects. Proximity sensor devices may be used to provide an interface for an electronic system. For example, proximity sensor devices are often used as input devices for larger computer systems (e.g., an opaque touch pad incorporated into or provided peripherally to a notebook or desktop personal computer). Proximity sensor devices are often combined with a display device to operate as an input display device (such as a touch screen incorporated into a mobile phone).

[0004] In an input display device, the proximity sensor device and the display device can be highly integrated. High integration can cause parasitic capacitance between the components of the proximity sensor device and the components of the display device. As a result, the sensing waveform emitted from the proximity sensor device can capacitively couple to the signals of the display device, thereby causing display distortion.

Summary of the Invention

[0005] Overall, in one respect, one or more embodiments relate to an input display device comprising a display screen provided on a display substrate. The display screen comprises a plurality of display pixels, capacitive sensing electrodes for capacitive sensing in the sensing area of ​​the display screen, and a source driver circuit. The source driver circuit is configured to generate a data voltage for driving a pixel circuit corresponding to one of the plurality of display pixels, determine the timing of compensatory modulation of the data voltage using the sensing waveform of capacitive sensing, determine the amplitude of the compensatory modulation, generate a modulated data voltage by performing compensatory modulation on the data voltage, and drive the pixel circuit using the modulated data voltage.

[0006] Overall, in one respect, one or more embodiments relate to a Touch Display Driver Integration (TDDI) circuit. The TDDI circuit includes a source driver circuit configured to generate a data voltage for driving pixel circuits corresponding to pixels on a display screen based on a post-processed image signal, determine the timing of compensatory modulation of the data voltage using a sensing waveform of capacitive sensing, determine the amplitude of the compensatory modulation, generate a modulated data voltage by performing compensatory modulation on the data voltage, and drive the pixel circuits using the modulated data voltage.

[0007] Overall, in one respect, one or more embodiments relate to a method for driving a display of an input display device. The method includes generating a data voltage for driving a pixel circuit of the display; determining the timing of compensatory modulation of the data voltage using a sensing waveform of capacitive sensing; determining the amplitude of the compensatory modulation; generating a modulated data voltage by performing compensatory modulation on the data voltage; and driving the pixel circuit using the modulated data voltage. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 illustrates an input device according to one or more embodiments.

[0009] [Figure 2A] Figure 2A illustrates an input device according to one or more embodiments.

[0010] [Figure 2B] Figure 2B illustrates an input device according to one or more embodiments.

[0011] [Figure 2C] Figure 2C illustrates an input device according to one or more embodiments.

[0012] [Figure 3A] Figure 3A illustrates uncompensated display driving.

[0013] [Figure 3B] Figure 3B illustrates a compensated display drive according to one or more embodiments.

[0014] [Figure 4] Figure 4 illustrates a flowchart according to one or more embodiments. [Modes for carrying out the invention]

[0015] The following detailed descriptions are essentially illustrative and are not intended to limit the disclosed technology or its uses and applications. Furthermore, they are not intended to be bound by the technical fields, backgrounds, or any express or implied theories presented in the descriptions below.

[0016] The detailed descriptions of the embodiments below include many specific details to provide a deeper understanding of the disclosed technology. However, it will be apparent to those skilled in the art that the disclosed technology can be implemented even without these specific details. In other examples, well-known mechanisms are not described in detail to avoid unnecessarily complicating the description.

[0017] Throughout the application, ordinal numbers (e.g., 1st, 2nd, 3rd, etc.) may be used as adjectives for elements (i.e., any noun in the application). The use of ordinal numbers does not suggest or produce a particular ordering of elements, nor does it limit any element to being a single element, unless explicitly disclosed by the use of words such as “before,” “after,” “single,” or other similar terms. Rather, the use of ordinal numbers is for distinguishing elements from one another. For example, the 1st element is distinguished from the 2nd element, the 1st element may encompass more than one element, and in the ordering of elements, it may follow (or precede) the 2nd element.

[0018] Input display devices, such as touchscreens, are widely used in various electronic systems. Input display devices often have a sensing area demarcated by a surface. Within this sensing area, the input display device detects the presence, position, movement, and / or force of one or more input objects. Touch sensing as used here includes proximity (e.g., no contact), touch (e.g., contact with an input surface), and force-applied contact. Touch sensing is performed using touch sensors. Touch sensors are electrodes used when performing touch sensing. Examples of touch sensing include mutual or transformer-capacitance sensing and absolute or self-capacitance sensing. In one or more embodiments, the input display device includes a display screen. The display screen may be used to display content or information to a user, and touch sensing may allow the user to interact with the displayed content. Touch sensing may include driving the touch sensor with a sensing waveform, such as a square wave. The presence of a sensing waveform on the touch sensor may cause interference on the display screen. This interference can cause display distortion, such as dark and / or bright areas on a display screen that appear as a striped pattern. In one or more embodiments, the display screen is driven in a manner that compensates for the interference so that the distortion is reduced or avoided.

[0019] FIG. 1 is a block diagram of an example of an input display device (100) according to one or more embodiments. The input display device (100) may be configured to supply an input to an electronic system (not shown). As used in this document, the term "electronic system" (or "electronic device") broadly refers to any system capable of electronically processing information. Some non-limiting examples of electronic systems include personal computers such as desktop computers, laptop computers, netbook computers, tablets, web browsers, e-book readers, smartphones, personal digital assistants (PDAs), automotive infotainment devices, game consoles, and the like.

[0020] In FIG. 1, the input display device (100) includes a proximity and / or force sensor device (e.g., a "touchpad" or "touch sensor device") configured to detect an input provided by one or more input objects in a detection area (120). Exemplary input objects include a stylus, an active pen, and a finger.

[0021] The detection area (120) encompasses any space above, around, and / or near the input display device (100) in which the input device (100) can detect a user input (e.g., a user input provided by one or more input objects). The specific size, shape, and location of the detection area can vary widely depending on the embodiment.

[0022] The input display device (100) may detect a user input in the detection area (120) using any combination of sensor components and sensing technologies. The input display device (100) includes one or more detection elements for detecting a user input. As a non-limiting example, the input display device (100) may use capacitive technology.

[0023] In some capacitive implementations of the input display device (100), a voltage or current is applied to generate an electric field. A nearby input object causes a change in the electric field, resulting in a detectable change in the capacitive coupling, which can be detected as a change in voltage, current, etc.

[0024] Some capacitive implementations use an array of capacitive sensing elements or other regular or irregular patterns to generate an electric field. In some capacitive implementations, separate sensing elements may be ohmic short-circuited to form a large sensor electrode.

[0025] Some capacitive implementations employ a “self-capacitance” (or “absolute capacitance”) sensing method based on changes in the capacitive coupling between the sensor electrode and the input object. In various embodiments, an input object near the sensor electrode changes the electric field near the sensor electrode, thereby changing the measured capacitive coupling. In one implementation, the absolute capacitance sensing method works by modulating the sensor electrode with respect to a reference voltage (e.g., system ground) and detecting the capacitive coupling between the sensor electrode and the input object. The reference voltage may be substantially constant, a variable voltage, or, in various embodiments, system ground. The measurement obtained using the absolute capacitance sensing method is sometimes called an absolute capacitance measurement.

[0026] Some capacitive implementations employ a “mutual capacitance” (or “trans-capacitance”) sensing method based on changes in the capacitive coupling between sensor electrodes. In various embodiments, an input object near the sensor electrodes alters the electric field between the sensor electrodes, thereby altering the measured capacitive coupling. In one implementation, the mutual capacitance sensing method operates by detecting the capacitive coupling between one or more transmitter sensor electrodes (also known as “transmitter electrodes” or “transmitters,” TX) and one or more receiver sensor electrodes (also known as “receiver electrodes” or “receivers,” RX). The transmitter sensor electrodes may be modulated with respect to a reference voltage (e.g., system ground) to transmit a transmitter signal. The receiver sensor electrodes may be held substantially constant with respect to the reference voltage to facilitate the reception of the resulting signal. The reference voltage may be a substantially constant voltage, and in various embodiments, the reference voltage may be system ground. In some embodiments, both the transmitter sensor electrodes and the receiver sensor electrodes may be modulated. The transmitter electrodes transmit a transmitter signal and are modulated with respect to the receiver electrodes to facilitate the reception of the resulting signal. The resulting signal may include effects corresponding to one or more transmitted signals and / or effects corresponding to one or more sources of interference from the environment (e.g., other electromagnetic signals). These effects may be the transmitter signal, changes in the transmitter signal caused by interference from one or more input objects and / or the environment, or other such effects. The sensor electrodes may be dedicated transmitters or receivers, or they may be configured to both transmit and receive. Measurements obtained using the mutual capacitance sensing method may be called mutual capacitance measurements.

[0027] Absolute capacitance measurements and / or mutual capacitance measurements may be used to determine when at least one input object is present in the detection area, to determine the signal-to-noise ratio, to determine the positional information of the input object, to identify a gesture, to determine an action to be taken based on the gesture, a combination of gestures, or other information, or to take other actions.

[0028] In Figure 1, the processing system (110) is shown as part of the input display device (100). The processing system (100) is configured to operate the hardware of the input display device (100) to detect input in the sensing area (120). The processing system (110) comprises one or more integrated circuits (ICs) and / or some and / or all of other circuit components. For example, the processing system may include circuitry for mutual and / or absolute capacitance sensing. In some embodiments, the processing system (110) may also include electronically readable instructions, such as firmware code, software code and / or similar. In some embodiments, the components constituting the processing system (110) are located together, for example, near the sensing element of the input display device (100). In other embodiments, the components of the processing system (110) are physically separated, with one or more components of the input display device (100) located near the sensing element and one or more components located elsewhere. For example, the input display device (100) may be a peripheral device coupled to a computing device, and the processing system (110) may comprise software running on the central processing unit of the computing device and one or more ICs (possibly with associated firmware) located away from the central processing unit. In another example, the input display device (100) may be physically integrated into a portable device, and the processing system (110) may comprise circuits and firmware that are part of the main processor of the portable device. In some embodiments, the processing system (110) is dedicated solely to the implementation of the input display device (100). In other embodiments, the processing system (110) may also perform other functions, such as driving a tactile actuator.

[0029] In some embodiments, the processing system (110) directly responds to user input (or lack thereof) in the detection area (120) by performing one or more actions. Exemplary actions include changes in operating mode, along with graphical user interface (GUI) actions such as cursor movement, selection, menu navigation, and other functions. In some embodiments, the processing system (110) provides information about the input (or lack thereof) to a part of the electronic system (for example, if there is a separate central processing system from the processing system (110) of the electronic system, such a separate central processing system). In some embodiments, the part of the electronic system processes the information received from the processing system (110) and operates according to the user input to facilitate a range of actions, including, for example, mode change actions and GUI actions.

[0030] In some embodiments, the input display device (100) is implemented with additional input components operated by a processing system (110) or some other processing system. These additional input components may provide redundant functionality for input in the sensing region (120), or some other functionality.

[0031] In some embodiments, the input display device (100) includes a touchscreen interface, and the sensing area (120) overlaps with at least a portion of the active area of ​​the display screen (155). For example, the input display device (100) may include substantially transparent sensor electrodes that overlap the display screen and provide a touchscreen interface for the associated electronic system. The display screen may be any type of dynamic display capable of displaying a visual interface to the user and may include any type of light-emitting diode (LED), organic light-emitting diode (OLED), micro-LED, liquid crystal display (LCD) or other display technology. The proximity and / or force sensor device of the input display device (100) and the display screen may share physical elements. For example, in some embodiments, some of the same electrical components may be used for display and sensing. In various embodiments, one or more display electrodes of the display device may be used for both display updating and input sensing. In another example, the display screen may be operated in part or entirely by a processing system (110).

[0032] Figure 1 illustrates the configuration of the components, but other configurations may be used without departing from the scope of the invention. For example, various components may be combined to form a single component. In other examples, a function performed by a single component may be performed by two or more components.

[0033] Figure 2A illustrates an input display device (200) according to one or more embodiments. As shown in Figure 2A, the input display device (200) comprises a detection display module (220) and a touch display driver integration (TDDI) circuit (250) coupled to the detection display module via wiring (205). The detection display module (220) may operate all or part of the detection area (120) and all or part of the display screen (155), as discussed above with reference to Figure 1.

[0034] In one or more embodiments, the detection display module (220) comprises a plurality of layers including a laminate of display layers (230), one or more capacitive sensing layers (232), and a display substrate (222). The display layers (230) constitute a display screen. In one embodiment, the display screen is an OLED display. Therefore, the laminate of display layers (230) may include OLED display layers such as one or more conductive layers that may include an organic light-emitting layer, an anode layer, a cathode layer, a thin-film transistor (TFT) layer, etc. The laminate of display layers (230) may be provided on a display substrate (222). In one embodiment, the display substrate (222) is a flexible plastic substrate so as to realize a flexible, rollable, and / or foldable OLED display.

[0035] The laminate of the display layer (230) may include a micro-LED layer, such as an LED layer, provided on a thin-film transistor (TFT) layer on a display substrate (222).

[0036] The laminate of the display layer (230) may include a color filter glass layer, a liquid crystal layer, and an LCD display layer such as a TFT layer formed on a display substrate (222) which may be glass.

[0037] The detection display module (220) may have additional layers and components. In one or more embodiments, a plurality of transmitter (TX) electrodes (234) and / or receiver (RX) electrodes (236) are provided on one or more capacitive sensing layers (232) in the detection area of ​​the display screen. The detection area may extend over the entire or a portion of the display screen. The TX electrodes (234) and / or RX electrodes (236) may be used in capacitive sensing (e.g., absolute capacitance sensing, mutual capacitance sensing, etc.) as described above with reference to Figure 1.

[0038] Figure 2A illustrates that the capacitive sensing layer (232) is provided on top of the display layer (230) laminate, but these layers may be provided at any position relative to the display layer (230) laminate. For example, one layer with an RX electrode (236) may be located at the upper end of the display layer (230) laminate, and another layer with a TX electrode (234) may be located in or below the display layer (230) laminate. Alternatively, there may be no layer with a TX electrode. In one or more embodiments, the sensing module (220) comprises a matrix pad sensor comprising many sensing pads and wiring connecting the sensing pads in a metal mesh layer spanning the sensing area. The matrix pad sensor may comprise at least one such metal mesh layer. Instead of using a dedicated metal mesh layer, a display layer, such as the cathode layer of an OLED display, may be molded to function as a metal mesh layer.

[0039] In one or more embodiments, the TX electrode (234) and the RX electrode (236) work together to perform mutual capacitance sensing. In other words, a waveform is applied to the TX electrode (234), and a resulting signal is received from the RX electrode (236). The resulting signal is a function of the waveform and the change in capacitance between the TX electrode and the RX electrode (234, 236) due to the presence of an input object.

[0040] In one or more embodiments, the RX electrode (236) is operated to perform absolute capacitance sensing independently of the TX electrode (234). In one or more embodiments, the transmitter electrode (234) is operated to perform absolute capacitance sensing independently of the receiver electrode (236).

[0041] In one or more embodiments, the laminate of the display layer (230) comprises one or more layers, such as a thin-film transistor (TFT) layer having source lines, gate lines and transistors for controlling individual OLED, LCD, or microLED units of display pixels (or pixels) of a display screen. In one or more embodiments, one or more source lines and / or one or more gate lines are also operated to perform absolute capacitance sensing.

[0042] In one or more embodiments, the touch display driver integration (TDDI) circuit (250) includes a source driver circuit (252) that drives transistors controlling pixels on a display screen. Each pixel may be an OLED pixel, a microLED pixel, a microOLED pixel, an LCD pixel, etc. The TDDI circuit (250) may receive an image signal from a host application processor (e.g., a video processor) or any other component (not shown) that provides image content to be displayed on the display screen (155). The received image signal may be in digital format. An image processing circuit (254) may process the received image signal and output a processed image signal. For example, the image processing circuit (254) may perform uniformity correction and / or other image processing operations. According to one or more embodiments, the processed image signal is supplied to the source driver circuit (252), where an analog signal may be generated to drive transistors corresponding to pixels on the display screen. The image processing circuit (254) may be integrated into the TDDI circuit (250), or the image processing circuit (254) may be located elsewhere. Without departing from this disclosure, any additional circuitry of any kind related to image display may be included in the TDDI circuit (250).

[0043] In one or more embodiments, the TDDI circuit (250) is further configured to perform capacitive sensing. The TDDI circuit (250) may drive a capacitive sensing electrode (e.g., a TX electrode (234) or a subset of TX electrodes (234)) and receive a result signal from the capacitive sensing electrode (e.g., from an RX electrode (236) or a subset of RX electrodes (236)) to detect the presence and / or location of an input object (e.g., an input object (140) discussed above with reference to Figure 1). The TDDI circuit (250) may comprise various components. In one embodiment, the TDDI circuit (250) includes an analog front-end (256) configured to perform capacitive sensing by driving a capacitive sensing electrode, receiving a result signal, and performing analog-to-digital conversion on the result signal. Digital processing may be performed elsewhere by a touch processing circuit (258), such as a microprocessor or a digital signal processor. In one embodiment, the TDDI circuit (250) comprises some or all elements of the touch processing circuit (258). Alternatively, the touch processing circuit (258) may be located elsewhere.

[0044] In one or more embodiments, the TDDI circuit (250) may be housed in a single semiconductor package, such as an application-specific integrated circuit (ASIC). The source driver circuit (252), image processing circuit (254), analog front-end (256), and / or touch processing circuit (258) may be on separate dies or on a single die in the semiconductor package. The semiconductor package may be mounted on the display substrate (222) or elsewhere. Furthermore, embodiments of the present disclosure may comprise a plurality of TDDI circuits, each corresponding to a different area of ​​the display of the sensing display module (220).

[0045] Figures 2B and 2C illustrate input display devices (260A, 260B) according to one or more embodiments, respectively. The input display devices (260A, 260B) include a display panel (272A, 272B) driven by a display chip (270A, 270B) and a touch panel (282A, 282B) driven by a touch chip (280A, 280B). The display chips (270A, 270B) may include components such as a source driver circuit and an image processing circuit, as described above. The touch chips (280A, 280B) may include components such as an analog front end and a touch processing circuit, as described above. Unlike the embodiments described with reference to Figure 2A, the display chips (270A, 270B) and the touch chips (280A, 280B) are not integrated into the TDDI circuit. The touch chips (280A, 280B) provide sensing waveforms (284A, 284B) for touch sensing. In one or more embodiments, the data of the sensing waveforms (284A, 284B) is shared with the display chips (270A, 270B). In the input display device (260A), the sensing waveform (284A) itself is supplied to the display chip (270A). Therefore, the display chip (270A) is informed of the timing, polarity, and amplitude of the sensing waveform (284A) by receiving it. In the input display device (260B), amplitude information (286B) and timing information (288B) are supplied separately. The timing (and polarity) information may be supplied by a pulse train supplied using general-purpose input / output (GPIO) pins. The amplitude information may be provided using a separate digital interface.

[0046] Referring to Figure 3A, an uncompensated display driver (300) is illustrated. A data line (302) transmits a data voltage (304) for driving a pixel, for example, a single OLED (306). The data voltage (304) may be a square wave signal emitted from the source driver circuit of the TDDI circuit, as described with reference to Figure 2A. Due to the resistance and capacitance associated with the wiring that transmits the data voltage (304) to the pixel circuit (308), the data voltage (304) includes an initial transient response. When the gate line (310) of the pixel circuit (308) is activated, the data voltage (304) on the data line (302) charges the capacitor Cst, causing a current based on the data voltage (304) to flow through the OLED (306). Since higher data voltages generally increase the light output, the output of the OLED (306) can thus be dominated by the data voltage (304). Although only a single OLED is illustrated, driving of the OLED can be performed for all OLEDs on the display screen. Various pixel circuits may be used, without departing from this disclosure. Furthermore, other display techniques mentioned above may be used, without departing from this disclosure.

[0047] In one or more embodiments, touch sensing occurs at least partially simultaneously with the driving of the display. As a result, the sensing waveform (312) may capacitively couple to the data voltage (304) in the pixel circuit (308) via an interference path (314) (gray arrow). Specifically, as shown, the sensing waveform (312) modulates the cathode potential (318), for example, R TRx and C TRx Based on the corresponding RC time constant, a cathode potential waveform as shown in Figure 3A is generated. Interference capacitance C between the cathode layer of the display (display cathode (316)) and the data line (302) interfFurthermore, the sensing waveform (312) may be coupled to the data voltage (304), thereby generating a degraded data voltage (320). The degraded data voltage (320) thus includes distortion of the data voltage (322) caused by the sensing waveform (312) (e.g., voltage fluctuations illustrated in Figure 3A). Distortion in the degraded data voltage (320) may cause fluctuations in the output of the OLED (306).

[0048] In Figure 3A, the skewed exemplary display output (330) illustrates the distortion that may be present in the display output. In this example, the distortion includes a non-uniform display output with rows of pixels that are brighter than specified and rows of pixels that are darker than specified. As a result of the distortion (322) at the degraded data voltage (320), the capacitor C of the OLED in the dark and bright regions of the display output is affected. st Based on the fact that the elements are charged to different voltages, some rows of pixels become brighter and some rows of pixels become darker. The effect described can occur in any sensing display module, but (as illustrated in Figure 2A) the layers are highly integrated with minimal spacing, and thus capacitive coupling between conductive elements (e.g., C interf This effect is particularly noticeable and therefore undesirable in large OLED-based sensing and display modules (e.g., flexible, rollable, and / or foldable OLED sensing and display modules). Furthermore, the described effect is particularly pronounced when absolute capacitance sensing is used, because all capacitance sensing electrodes involved in absolute capacitance touch sensing are modulated in the same phase. However, this effect can also be noticeable in transformer capacitance sensing configurations where only some of the capacitance sensing electrodes are modulated, or where opposite-phase modulation may be used to reduce the effect. Similarly, this effect can also be noticeable in hybrid sensing configurations that combine absolute capacitance sensing and transformer capacitance sensing.

[0049] Referring to Figure 3B, a compensated display driver (350) according to one or more embodiments is illustrated. The various elements illustrated in Figure 3B are substantially similar to or identical to the corresponding elements illustrated in Figure 3A. In one or more embodiments, the data voltage emitted by the source driver circuit is a modulated data voltage (354). The modulated data voltage (354) may be subjected to compensatory modulation (358). Compensatory modulation (358) may be selected to eliminate, or at least reduce, the degradation in the degraded data voltage (320) illustrated in Figure 3A. Since the modulated data voltage (354) is compensated, an undegraded data voltage (356) may exist in the pixel circuit (308) rather than a degraded data voltage (356).

[0050] The modulated data voltage (354) may be based on the data voltage (304) with compensatory modulation (358) superimposed. In one or more embodiments, the compensatory modulation (358) is selected to eliminate, or at least reduce, the distortion (322) of the degraded data voltage (320) in Figure 3A. To reduce or eliminate the distortion (322), the source driver circuit superimposes the compensatory modulation (358) on the data voltage to obtain the modulated data voltage (354). Characteristics of the compensatory modulation (358) include the timing and amplitude of the compensatory modulation (358). The characteristics of the compensatory modulation (358) may be selected to effectively cancel the effect that the sensing waveform (312) has on the data voltage via the interference path (314).

[0051] Figure 3B illustrates a complete cancellation operation with no distortion in the non-degraded data voltage (356). In partial cancellation, reduced distortion may remain (compared to the distortion (322) in Figure 3A). The timing of the compensatory modulation (358) may be available from the analog front-end emitting the sensing waveform. This timing may then be supplied from the analog front-end to the source driver circuit. In other configurations where the source driver circuit and analog front-end are not integrated in the TDDI circuit, the timing of the source driver circuit may be supplied externally to the source driver circuit for synchronization. The amplitude of the amplitude modulation (358) may be obtained by experimental measurement and optimization, and / or by circuit modeling of the input display device, including the capacitance and resistance of the input display device. The magnitude of the distortion (322) may not be fixed and may depend, for example, on the amplitude of the touch sensing waveform (312). Therefore, different amplitudes of compensatory modulation (358) may be used depending on the amplitude of the touch sensing waveform (312). In this scenario, the amplitude of the touch sensing waveform (312) is obtained from the analog front-end (256). In a configuration where the analog front-end (256) and the source driver circuit (252) are integrated into the TDDI circuit (250) (for example, Figure 2A), the source driver circuit (252) may obtain the amplitude of the touch sensing waveform directly from the analog front-end (256). In a configuration where the analog front-end (256) and the source driver circuit (252) are not integrated (for example, Figures 2B and 2C), the amplitude of the touch sensing waveform may be transmitted, for example, using general-purpose input / output pins.

[0052] In one embodiment, the source driver circuit performs compensatory modulation (358) on the data voltage using a modified gamma transform. The gamma transform may convert the gradation specified by the input image data for each pixel circuit into a voltage value (i.e., data voltage) that specifies the output voltage level at which the pixel circuit is updated. The modified gamma transform further applies compensatory modulation (358) as an amplitude increment (positive or negative) to the data voltage output to the pixel circuit (308) using the timing.

[0053] Figure 4 illustrates a flowchart according to one or more embodiments. While the various steps in this flowchart are presented and described sequentially, those skilled in the art will understand that some or all of the steps may be performed in a different order, combined, or omitted, and some or all of the steps may be performed in parallel. Additional steps may be performed. Therefore, the scope of this disclosure should not be considered limited to the specific sequence of steps illustrated in Figure 4.

[0054] The flowchart in Figure 4 illustrates a method for driving the display of an input display device according to one or more embodiments. The following description pertains to driving a single pixel circuit corresponding to a single display pixel, but the same steps may be performed to drive additional pixel circuits of the input display device.

[0055] In step 402, a data voltage is generated to drive the pixel circuit. The data voltage may be generated based on an image signal. For example, the image signal may be received by an image processing circuit. The image signal may be received from a host application processor. The image processing circuit may generate a processed image signal by performing various operations as described above. The source driver circuit may operate based on the processed image signal and generate a data voltage as described above.

[0056] In step 404, the timing of the compensatory modulation of the data voltage is determined. This timing may be obtained from an analog front-end that emits a sensing waveform related to capacitive sensing. For example, the analog front-end may use a control signal to trigger the emission of the sensing waveform, which may be obtained by a source driver circuit to identify the start of the emission of the sensing waveform.

[0057] In step 406, the amplitude of the compensatory modulation of the data voltage is determined. The amplitude may be described by a variable or constant stored in memory. The amplitude of the compensatory modulation may be obtained empirically. Alternatively, the amplitude of the compensatory modulation may be obtained by modeling and / or simulation.

[0058] In step 408, a modulated data voltage is generated by performing compensatory modulation on the data voltage. Compensatory modulation may be performed in addition to the data voltage. In one embodiment, the source driver performs a gamma transform to obtain the data voltage from the grayscale specified by the image data. Compensatory modulation may be performed as part of the gamma transform.

[0059] In step 410, the pixel circuit is driven using the modulated data voltage. During the driving of the pixel circuit, the storage capacitor may be charged with the modulated data voltage. The modulated data voltage of the storage capacitor may specify the light emission intensity of the pixel.

[0060] Embodiments of the present disclosure can suppress or reduce display distortion without changing the voltage or frequency of the sensing waveform. Therefore, embodiments of the present disclosure enable the parameters of touch sensing relating to the sensing waveform to be determined based on other considerations (for example, determining the sensing frequency based on the RC bandwidth of the touch sensor to avoid display noise or the frequency of a noisy charger), thereby making the input display device easier to set up and more stable.

[0061] Embodiments of this disclosure may be suitable for implementations using a TDDI architecture that combines source driver circuitry related to image display with an analog front-end related to touch sensing. Embodiments of this disclosure may also be used when the source driver circuitry is separated from the analog front-end.

[0062] Although the invention is described in relation to a limited number of embodiments, a person skilled in the art who has an interest in this disclosure will understand that other embodiments can be devised that do not deviate from the scope of the invention disclosed herein. Therefore, the scope of the invention should be limited only by the claims.

Claims

1. An input display device, A display screen formed on a display substrate and having multiple display pixels, Multiple capacitance sensing electrodes for capacitance sensing in the detection area of ​​the display screen, A data voltage is generated to drive a pixel circuit corresponding to one of the multiple display pixels. The timing of the compensation modulation of the data voltage is determined using the sensing waveform of the capacitance sensing. Determine the amplitude of the compensation modulation, The modulated data voltage is generated by performing the aforementioned compensation modulation on the data voltage. The pixel circuit is driven using the modulated data voltage. A source driver circuit configured as follows, Equipped with, The amplitude of the compensation modulation is at least partially based on the measured capacitance in the input display device and the amplitude of the sensing waveform. Different amplitudes of the compensation modulation are used depending on the amplitude of the sensing waveform. Input display device.

2. An image processing circuit configured to generate a processed image signal based on a received image signal acquired from a host application processor, The source driver circuit and, An analog front end for the capacitance sensing, which operates as an interface with the capacitance sensing electrode to acquire a plurality of touch signals and generate the sensing waveform, It further includes a touch display driver integrated circuit (TDDI) equipped with, The source driver circuit is configured to generate the data voltage based on the processed image signal. The input display device according to claim 1.

3. The TDDI circuit further comprises a touch processing circuit configured to generate a touch output signal by processing the plurality of touch signals. The input display device according to claim 2.

4. Determining the timing of the compensated modulation includes obtaining the timing from the analog front end. The input display device according to claim 2.

5. The amplitude of the compensation modulation is selected to at least partially compensate for the distortion of the data voltage in the pixel circuit related to the sensing waveform coupled to the data voltage via parasitic capacitance. The input display device according to claim 1.

6. Performing the compensation modulation on the data voltage includes additionally superimposing the compensation modulation on the data voltage. The input display device according to claim 1.

7. The source driver circuit is further configured to perform gamma conversion to obtain the data voltage from the grayscale specified by the input image data. The gamma conversion includes performing the compensation modulation on the data voltage as an amplitude increment. The input display device according to claim 1.

8. The aforementioned display screen is an OLED display screen. The input display device according to claim 1.

9. The aforementioned display screen is equipped with a display cathode, The display cathode is one of the plurality of capacitive sensing electrodes. The input display device according to claim 1.

10. A touch display driver integrated circuit (TDDI), Generate data voltages to drive the pixel circuits corresponding to the pixels of the display screen. The timing of the compensation modulation of the data voltage is determined using the sensing waveform of the capacitive sensing. Determine the amplitude of the compensation modulation, The modulated data voltage is generated by performing the aforementioned compensation modulation on the data voltage. The pixel circuit is driven using the modulated data voltage. It includes a source driver circuit configured as follows: The amplitude of the compensation modulation is at least partially based on the measured capacitance and the amplitude of the sensing waveform in the input display device equipped with the TDDI circuit. Different amplitudes of the compensation modulation are used depending on the amplitude of the sensing waveform. TDDI circuit.

11. The analog front end for the capacitance sensing further comprises an analog front end that acts as an interface with a plurality of capacitance sensing electrodes to acquire a plurality of touch signals and generate the sensing waveform. The TDDI circuit according to claim 10.

12. An image processing circuit configured to generate a processed image signal based on a received image signal acquired from a host application processor, A touch processing circuit configured to generate a touch output signal by processing the aforementioned plurality of touch signals, Furthermore, The source driver circuit is configured to generate the data voltage based on the processed image signal. The TDDI circuit according to claim 11.

13. Determining the timing of the compensated modulation includes obtaining the timing from the analog front end. The TDDI circuit according to claim 11.

14. The amplitude of the compensation modulation is selected to at least partially compensate for the distortion of the data voltage in the pixel circuit related to the sensing waveform coupled to the data voltage via parasitic capacitance. The TDDI circuit according to claim 10.

15. Performing the compensation modulation on the data voltage includes additionally superimposing the compensation modulation on the data voltage. The TDDI circuit according to claim 10.

16. The source driver circuit is further configured to perform gamma conversion to obtain the data voltage from the grayscale specified by the input image data. The gamma conversion includes performing the compensation modulation on the data voltage as an amplitude increment. The TDDI circuit according to claim 10.

17. A method for driving the display of an input display device, To generate a data voltage for driving the pixel circuit of the aforementioned display, The timing of the compensation modulation of the aforementioned data voltage is determined using the sensing waveform of the capacitive sensing, Determining the amplitude of the aforementioned compensation modulation, The modulated data voltage is generated by performing the aforementioned compensation modulation on the data voltage, The pixel circuit is driven using the modulated data voltage, Includes, The amplitude of the compensation modulation is at least partially based on the measured capacitance in the input display device and the amplitude of the sensing waveform. Different amplitudes of the compensation modulation are used depending on the amplitude of the sensing waveform. method.

18. Determining the timing of the compensation modulation is An analog front end for proximity detection, comprising acquiring the timing from the analog front end configured to generate the sensing waveform. The method according to claim 17.

19. Performing the compensation modulation on the data voltage includes additionally superimposing the compensation modulation on the data voltage. The method according to claim 17.

20. The method further includes performing a gamma conversion to obtain the data voltage from the grayscale specified by the input image data, The gamma conversion includes performing the compensation modulation on the data voltage as an amplitude increment. The method according to claim 17.

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