PATENT DOCUMENT

Publication Number: US-11205363-B2
Application Number: US-202017016282-A
Country: US
Kind Code: B2

Title: Electronic display cross-talk compensation systems and methods

Abstract:
An electronic display may include pixel circuitry to display an image based on image data compensated for voltage variations within the pixel circuitry. Image processing circuitry may generate a compensation value to compensate the image data for cross-talk (e.g., electromagnetic coupling between an electrode of touch sensor circuitry and an electrode of the pixel circuitry) that may cause the voltage variations. Additionally or alternatively, the image processing circuitry may generate another compensation value to compensate the image data for another cross-talk (e.g., electromagnetic coupling between two electrodes of the pixel circuitry). The image processing circuitry may generate the compensated image data based on the first compensation value and/or the second compensation value.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 an electronic display comprising pixel circuitry and configured to display an image based at least in part on compensated image data; and 
 image processing circuitry configured to compensate input image data for voltage variations within the pixel circuitry of a plurality of pixels of the electronic display, wherein the image processing circuitry comprises:
 touch cross-talk compensation circuitry configured to generate a first compensation value to compensate the input image data for a first cross-talk causing, at least in part, the voltage variations, wherein the first cross-talk comprises a first electromagnetic coupling between a first electrode of touch sensor circuitry and a second electrode of the pixel circuitry, and wherein the image processing circuitry is configured to generate the compensated image data based at least in part on the first compensation value; or 
 reference voltage cross-talk compensation circuitry configured to generate a second compensation value to compensate the input image data for a second cross-talk causing, at least in part, the voltage variations, wherein the second cross-talk comprises a second electromagnetic coupling between a third electrode of the pixel circuitry and the second electrode, and wherein the image processing circuitry is configured to generate the compensated image data based at least in part on the second compensation value. 
 
 
     
     
       2. The electronic device of  claim 1 , wherein the first cross-talk comprises a change in a data line voltage signal of the second electrode based at least in part on a touch stimulus signal on the first electrode. 
     
     
       3. The electronic device of  claim 2 , wherein the first compensation value is generated based at least in part on a frequency of the touch stimulus signal. 
     
     
       4. The electronic device of  claim 1 , wherein the first compensation value for a given pixel of the plurality of pixels is generated based at least in part on a location of the given pixel on the electronic display. 
     
     
       5. The electronic device of  claim 1 , wherein the second cross-talk comprises a first change in a reference voltage of the third electrode in response to a second change in a data line voltage signal of the second electrode. 
     
     
       6. The electronic device of  claim 1 , wherein the reference voltage cross-talk compensation circuitry is configured to estimate an error in a reference voltage of the third electrode based at least in part on a change in voltage of the second electrode during a transition from programming of a first row of the electronic display to programming of a second row of the electronic display. 
     
     
       7. The electronic device of  claim 1 , wherein the reference voltage cross-talk compensation circuitry is configured to estimate an error in a reference voltage of the third electrode for a given pixel based at least in part on an aggregate of a plurality of individual errors associated with a row of pixels of the plurality of pixels. 
     
     
       8. The electronic device of  claim 7 , wherein the aggregate comprises a spatial average of the plurality of individual errors about the given pixel. 
     
     
       9. The electronic device of  claim 1 , wherein the reference voltage cross-talk compensation circuitry is configured to estimate an error in a reference voltage of the third electrode based at least in part by referencing a look-up-table configured to map a difference between a first data line voltage signal of the second electrode during programming of a first pixel of the plurality of pixels and a second data line voltage signal of the second electrode during programming of a second pixel of the plurality of pixels to the error.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/923,373, “ELECTRONIC DISPLAY CROSS-TALK COMPENSATION SYSTEMS AND METHODS,” filed Oct. 18, 2019, which is herein incorporated by reference in its entirety for all purposes. 
    
    
     SUMMARY 
     A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. 
     In general, the display of an electronic device may be compactly packaged with other components, for example, to reduce the size of the overall electronic device and/or allow space for additional components. Additionally, the density of pixels in the display may be increased for increased resolution and fidelity. However, the close proximity of electrical signals routed to and from the various components of the electronic device, including the pixels, may result in “cross-talk” (e.g., parasitic capacitance, current leakage, voltage variations, and other forms of electromagnetic interference) within the pixel circuitry (e.g., data lines, reference voltage lines, etc.) and/or between the pixel circuitry and other components of the electronic device, such as touch sensor circuitry. Such cross-talk may lead to variations in luminance of the pixels, which may manifest as perceivable artifacts on the display. The present disclosure generally relates to systems and methods for compensating the image data sent to the pixels of an electronic display for cross-talk within the pixel circuitry and/or between the pixel circuitry and the touch sensor circuitry. This may counteract the effect of cross-talk before the image data even reaches the display. 
     For example, in some embodiments, a touch stimulus signal may be employed in the touch sensor circuitry to facilitate detecting a user input (e.g., a finger or stylus touching the electronic device) and/or determining the placement of the user input relative to the electronic display. However, the touch stimulus signal may cross-talk with the pixel circuitry causing variations in the luminance output of the pixels. In some embodiments, the electronic device may compensate the image data to the pixels based on the frequency of the touch stimulus signal and/or the location of the pixels on the display panel. The compensation to the image data may increase or decrease the voltage of the data signal sent to a pixel to counter the cross-talk from the touch sensor circuitry (e.g., the touch stimulus signal). 
     Additionally or alternatively, cross-talk may occur between data lines, reference lines, or other conductive lines within the pixel circuitry. For example, a reference voltage (e.g., VDDEL or VSSEL) of the pixels may cross-talk with one or more data line voltage signals of the pixels causing the difference between the reference voltage and the data line voltage signal of a given pixel and, therefore, the apparent applied signal to the pixel to increase or decrease. In some embodiments, the electronic device may counter the cross-talk between the conductive lines within the pixel circuitry by anticipating an increase or decrease to the reference voltage and adjusting the image data accordingly to maintain the desired apparent applied signal (e.g., associated with the image data) to the pixel. Moreover, in some embodiments, the anticipated change in the reference voltage may be determined based on the aggregate of multiple pixel transitions (e.g., changes in the data line voltage signal from one row of pixels to the next). 
     Various refinements of the features noted above may exist in relation to various aspects of the present disclosure. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. The brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of embodiments of the present disclosure without limitation to the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which: 
         FIG. 1  is a block diagram of an electronic device including an electronic display, in accordance with an embodiment; 
         FIG. 2  is an example of the electronic device of  FIG. 1 , in accordance with an embodiment; 
         FIG. 3  is another example of the electronic device of  FIG. 1 , in accordance with an embodiment; 
         FIG. 4  is another example of the electronic device of  FIG. 1 , in accordance with an embodiment; 
         FIG. 5  is another example of the electronic device of  FIG. 1 , in accordance with an embodiment; 
         FIG. 6  is a block diagram of a portion of the electronic device of  FIG. 1  including a display pipeline that has cross-talk compensation circuitry, in accordance with an embodiment; 
         FIG. 7  is a block diagram of a portion of the display pipeline of  FIG. 6  including the cross-talk compensation block, in accordance with an embodiment; 
         FIG. 8  is a schematic diagram of pixel circuitry, in accordance with an embodiment; 
         FIG. 9  is a schematic diagram of a portion of an electronic display, in accordance with an embodiment; 
         FIG. 10  is a schematic diagram of a portion of the electronic device including a touch sensor sub-system, in accordance with an embodiment; 
         FIG. 11  is a schematic diagram of cross-talk between a touch layer and a display layer of the electronic device, in accordance with an embodiment; 
         FIG. 12  is a depiction of visual artifacts on an electronic display such as banded patterns, in accordance with an embodiment; 
         FIG. 13  is a flowchart of an example process for compensating image data for touch sensor cross-talk, in accordance with an embodiment; 
         FIG. 14  is a schematic diagram of cross-talk between electrodes of pixel circuitry, in accordance with an embodiment; 
         FIG. 15  is a graph of a reference voltage reaction to a change in a data line voltage signal, in accordance with an embodiment; 
         FIG. 16  is a graph of a data line voltage signal compensated for the reference voltage reaction, in accordance with an embodiment; and 
         FIG. 17  is a flowchart of an example process for compensating for cross-talk between a reference voltage supply line and data lines of the pixel circuitry, in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
     Numerous electronic devices—including televisions, portable phones, computers, wearable devices, vehicle dashboards, virtual-reality glasses, and more—display images on an electronic display. As electronic displays gain increasingly higher pixel density (e.g., for higher resolution) and/or are more compact (e.g., thinner), they may also become increasingly more susceptible to image display artifacts due to cross-talk between electrical signals within the electronic device. Indeed, the close proximity of electrical signals routed to and from the various components of the electronic device, including the pixels, may result in cross-talk such as parasitic capacitance, current leakage, voltage variations, and other forms of electromagnetic interference. The cross-talk may occur within the pixel circuitry (e.g., data lines, reference voltage lines, etc.) and/or between the pixel circuitry and other components of the electronic device, such as touch sensor circuitry. Such cross-talk may lead to variations in luminance of the pixels, which may manifest as visual artifacts on the display. 
     In some embodiments, in some embodiments, a touch stimulus signal may be employed in the touch sensor circuitry to facilitate detecting a user input (e.g., a finger or stylus touching the electronic device) and/or determining the placement of the user input relative to the electronic display. However, the touch stimulus signal may cross-talk with the pixel circuitry causing variations in the luminance output of the pixels. In some embodiments, the electronic device may compensate the image data to the pixels based on the frequency of the touch stimulus signal and/or the location of the pixels on the display panel. The compensation to the image data may increase or decrease the voltage of the data signal sent to a pixel to counter the cross-talk from the touch sensor circuitry (e.g., the touch stimulus signal). 
     Additionally or alternatively, cross-talk may occur between data lines, reference lines, or other conductive lines within the pixel circuitry. For example, a reference voltage (e.g., VDDEL or VSSEL) of the pixels may cross-talk with one or more data line voltage signals of the pixels causing the difference between the reference voltage and the data line voltage signal of a given pixel and, therefore, the apparent applied signal to the pixel to increase or decrease. In some embodiments, the electronic device may counter the cross-talk between the conductive lines within the pixel circuitry by anticipating an increase or decrease to the reference voltage and adjusting the image data accordingly to maintain the desired apparent applied signal (e.g., associated with the image data) to the pixel. Moreover, in some embodiments, the anticipated change in the reference voltage may be determined based on the aggregate of multiple pixel transitions (e.g., changes in the data line voltage signal from one row of pixels to the next). 
     In some embodiments, compensation of the image data for the pixel circuitry cross-talk and/or touch sensor cross-talk may be accomplished within image processing circuitry (e.g., a display pipeline) before being sent to a display driver of the electronic display and/or within the electronic display. In other words, image processing for the compensation of cross-talk may be accomplished within a display pipeline, at the display driver, or at any suitable point in the flow of image data from an image data source to the pixel to reduce the likelihood of perceivable artifacts (e.g., banding, color or luminance variations, etc.) on the electronic display. 
     To help illustrate, one embodiment of an electronic device  10  that utilizes an electronic display  12  is shown in  FIG. 1 . As will be described in more detail below, the electronic device  10  may be any suitable electronic device, such as a handheld electronic device, a tablet electronic device, a notebook computer, and the like. Thus, it should be noted that FIG.  1  is merely one example of a particular implementation and is intended to illustrate the types of components that may be present in the electronic device  10 . 
     In the depicted embodiment, the electronic device  10  includes the electronic display  12 , input devices  14 , input/output (I/O) ports  16 , a processor core complex  18  having one or more processors or processor cores, local memory  20 , a main memory storage device  22 , a network interface  24 , a power source  26 , and image processing circuitry  27 . The various components described in  FIG. 1  may include hardware elements (e.g., circuitry), software elements (e.g., a tangible, non-transitory computer-readable medium storing instructions), or a combination of both hardware and software elements. It should be noted that the various depicted components may be combined into fewer components or separated into additional components. For example, the local memory  20  and the main memory storage device  22  may be included in a single component. Additionally, the image processing circuitry  27  (e.g., a graphics processing unit, a display image processing pipeline) may be included in the processor core complex  18 , the electronic display  12 , or include standalone circuitry. 
     As depicted, the processor core complex  18  is operably coupled with local memory  20  and the main memory storage device  22 . In some embodiments, the local memory  20  and/or the main memory storage device  22  may include tangible, non-transitory, computer-readable media that store instructions executable by the processor core complex  18  and/or data to be processed by the processor core complex  18 . For example, the local memory  20  may include random access memory (RAM) and the main memory storage device  22  may include read only memory (ROM), rewritable non-volatile memory such as flash memory, hard drives, optical discs, and/or the like. 
     In some embodiments, the processor core complex  18  may execute instruction stored in local memory  20  and/or the main memory storage device  22  to perform operations, such as generating source image data. As such, the processor core complex  18  may include one or more general purpose microprocessors, one or more application specific processors (ASICs), one or more field programmable logic arrays (FPGAs), or any combination thereof. 
     As depicted, the processor core complex  18  is also operably coupled with the network interface  24 . Using the network interface  24 , the electronic device  10  may be communicatively coupled to a network and/or other electronic devices. For example, the network interface  24  may connect the electronic device  10  to a personal area network (PAN), such as a Bluetooth network, a local area network (LAN), such as an 802.11x Wi-Fi network, and/or a wide area network (WAN), such as a 4G or LTE cellular network. In this manner, the network interface  24  may enable the electronic device  10  to transmit image data to a network and/or receive image data from the network. 
     Additionally, as depicted, the processor core complex  18  is operably coupled to the power source  26 . In some embodiments, the power source  26  may provide electrical power to operate the processor core complex  18  and/or other components in the electronic device  10  such as the electronic display  12 . Thus, the power source  26  may include any suitable source of energy, such as a rechargeable lithium polymer (Li-poly) battery and/or an alternating current (AC) power converter. 
     Furthermore, as depicted, the processor core complex  18  is operably coupled with the I/O ports  16  and the input devices  14 . In some embodiments, the I/O ports  16  may enable the electronic device  10  to interface with various other electronic devices. Additionally, in some embodiments, the input devices  14  may enable a user to interact with the electronic device  10 . For example, the input devices  14  may include buttons, keyboards, mice, trackpads, and the like. Additionally or alternatively, the electronic display  12  may include touch sensing components that enable user inputs to the electronic device  10  by detecting occurrence and/or position of an object touching its screen (e.g., surface of the electronic display  12 ). As should be appreciated, touch sensor circuitry may be integrated into the electronic display  12  or be implemented as a separate “layer” of circuitry on the surface of the electronic display  12 . 
     In addition to enabling user inputs, the electronic display  12  may facilitate providing visual representations of information by displaying one or more images (e.g., image frames or pictures). For example, the electronic display  12  may display a graphical user interface (GUI) of an operating system, an application interface, text, a still image, or video content. To facilitate displaying images, the electronic display  12  may include a display panel with one or more display pixels. Additionally, each display pixel may include one or more sub-pixels that each control the luminance of one color component (e.g., red, blue, or green). As should be appreciated, a pixel may include any suitable grouping of sub-pixels such as red, blue, green, and white (RBGW), or other color sub-pixel, and/or may include multiple of the same color sub-pixel. For example, a pixel may include one blue sub-pixel, one red sub-pixel, and two green sub-pixels (GRGB). As used herein for simplicity, the term “pixel” may generally refer to a single sub-pixel or grouping of sub-pixels. 
     As described above, the electronic display  12  may display an image by controlling luminance of the pixels based at least in part on corresponding image data. In some embodiments, the image data may be received from another electronic device, for example, via the network interface  24  and/or the I/O ports  16 . Additionally or alternatively, the image data may be generated by the processor core complex  18  and/or the image processing circuitry  27 . 
     As described above, the electronic device  10  may be any suitable electronic device. To help illustrate, one example of a suitable electronic device  10 , specifically a handheld device  10 A, is shown in  FIG. 2 . In some embodiments, the handheld device  10 A may be a portable phone, a media player, a personal data organizer, a handheld game platform, and/or the like. For example, the handheld device  10 A may be a smart phone, such as any iPhone® model available from Apple Inc. 
     As depicted, the handheld device  10 A includes an enclosure  28  (e.g., housing). In some embodiments, the enclosure  28  may protect interior components from physical damage and/or shield them from electromagnetic interference. Additionally, as depicted, the enclosure  28  may surround and/or provide a structural frame for the electronic display  12 . In the depicted embodiment, the electronic display  12  is displaying a graphical user interface (GUI)  30  having an array of icons  32 . By way of example, when an icon  32  is selected either by an input device  14  or touch sensor circuitry of the electronic display  12 , an application program may launch. 
     Furthermore, as depicted, input devices  14  open through the enclosure  28 . As described above, the input devices  14  may enable a user to interact with the handheld device  10 A. For example, the input devices  14  may enable the user to activate or deactivate the handheld device  10 A, navigate a user interface to a home screen, navigate a user interface to a user-configurable application screen, activate a voice-recognition feature, provide volume control, and/or toggle between vibrate and ring modes. As depicted, the I/O ports  16  also open through the enclosure  28 . In some embodiments, the I/O ports  16  may include, for example, an audio jack to connect to external devices. 
     To further illustrate, another example of a suitable electronic device  10 , specifically a tablet device  10 B, is shown in  FIG. 3 . For illustrative purposes, the tablet device  10 B may be any iPad® model available from Apple Inc. A further example of a suitable electronic device  10 , specifically a computer  10 C, is shown in  FIG. 4 . For illustrative purposes, the computer  10 C may be any MacBook® or iMac® model available from Apple Inc. Another example of a suitable electronic device  10 , specifically a wearable electronic device  10 D, is shown in  FIG. 5 . For illustrative purposes, the wearable electronic device  10 D may be any Apple Watch® model available from Apple Inc. More generally, the wearable electronic device  10 D may be any wearable electronic device such as, for example, a wearable exercise monitoring device (e.g., pedometer, accelerometer, heart rate monitor), or other device by another manufacturer. As depicted, the tablet device  10 B, the computer  10 C, and the wearable electronic device  10 D each also includes an electronic display  12 , input devices  14 , I/O ports  16 , and an enclosure  28 . 
     As described above, the electronic display  12  may display images based at least in part on image data received, for example, from the processor core complex  18  and/or the image processing circuitry  27 . Additionally, as described above, the image data may be processed before being used to display a corresponding image on the electronic display  12 . In some embodiments, a display pipeline may process the image data, for example, to identify and/or compensate for cross-talk between the circuitry of the electronic device  10 . 
     To help illustrate, a portion  34  of the electronic device  10  including a display pipeline  36  is shown in  FIG. 6 . In some embodiments, the display pipeline  36  may be implemented by circuitry in the electronic device  10 , circuitry in the electronic display  12 , or a combination thereof. For example, the display pipeline  36  may be included in the processor core complex  18 , the image processing circuitry  27 , a timing controller (TCON) in the electronic display  12 , a display driver of the electronic display, or any combination thereof. 
     The depicted portion  34  of the electronic device  10  also includes an image data source  38 , a display panel  40 , and a controller  42 . In some embodiments, the display panel  40  of the electronic display  12  may include a light emitting diode (LED) display, organic light emitting diode (OLED) display, active-matrix organic light emitting diode (AMOLED) display, liquid crystal (LCD) display, or any other suitable type of display panel  40 . In some embodiments, the controller  42  may control operation of the display pipeline  36 , the image data source  38 , and/or the display panel  40 . To facilitate controlling operation, the controller  42  may include a controller processor and/or controller memory. In some embodiments, the controller processor may be included in the processor core complex  18 , the image processing circuitry  27 , a timing controller in the electronic display  12 , a separate processing module, or any combination thereof and execute instructions stored in the controller memory. Additionally, in some embodiments, the controller memory may be included in the local memory  20 , the main memory storage device  22 , a separate tangible, non-transitory, computer readable medium, or any combination thereof. 
     In the depicted embodiment, the display pipeline  36  is communicatively coupled to the image data source  38 . In this manner, the display pipeline  36  may receive input image data corresponding with an image to be displayed on the electronic display  12  from the image data source  38 . The input image data may indicate target characteristics (e.g., pixel data of target luminance values) corresponding to a desired image using any suitable source format, such as an 8-bit fixed point αRGB format, a 10-bit fixed point αRGB format, a signed 16-bit floating point αRGB format, an 8-bit fixed point YCbCr format, a 10-bit fixed point YCbCr format, a 12-bit fixed point YCbCr format, and/or the like. In some embodiments, the image data source  38  may be included in the processor core complex  18 , the image processing circuitry  27 , or a combination thereof. Furthermore, the input image data may reside in a linear color space, a gamma-corrected color space, or any other suitable color space. 
     As described above, the display pipeline  36  may operate to process image data received from the image data source  38 . The display pipeline  36  may include one or more image data processing blocks  44  (e.g., circuitry, modules, or processing stages) such as the cross-talk compensation block  46  and/or one or more other processing blocks  48 . As should be appreciated, multiple image data processing blocks may be incorporated into the display pipeline  36 , such as a color management block, a dither block, a burn-in compensation block, etc. Further, the functions (e.g., operations) performed by the display pipeline  36  may be divided or shared between various image data processing blocks and/or sub-blocks, and while the term “block” is used herein, there may or may not be a physical or logical separation between the image data processing blocks  48  and/or sub-blocks thereof. 
     After processing, the display pipeline  36  may output the image data to the display panel  40 , and, based on the processed image data, the display panel  40  may apply analog electrical signals to the pixels of the electronic display  12  to cumulatively display one or more corresponding images. In this manner, the display pipeline  36  may facilitate providing visual representations of information on the electronic display  12 . As should be appreciated, the display pipeline  36  may be implemented in dedicated circuitry and/or, in whole or in part, by executing instructions stored in a tangible non-transitory computer-readable medium, such as the controller memory, using processing circuitry, such as the controller processor. 
     The cross-talk compensation block  46  may include a touch sensor cross-talk compensation sub-block  52  and a reference voltage cross-talk compensation sub-block  54 , as shown in the block diagram of  FIG. 7 . The touch sensor cross-talk compensation sub-block  52  and the reference voltage cross-talk compensation sub-block  54  may assist in reducing the likelihood of perceivable artifacts such as banding and/or color/brightness inaccuracies that may be caused due to cross-talk between data lines of pixel circuitry and/or touch sensor circuitry. In general, the cross-talk compensation block  46  may receive input image data  56 , generate compensated image data  58  via the touch sensor cross-talk compensation sub-block  52  and/or the reference voltage cross-talk compensation sub-block  54 , and output the compensated image data  58  to the other processing blocks  48 , the display panel  40 , and/or the pixels. Moreover, in some embodiments, the touch sensor cross-talk compensation sub-block  52  and the reference voltage cross-talk compensation sub-block  54  may be implemented together (e.g., via a combined compensation), sequentially (e.g., a first compensation followed by a second compensation), or be implemented separately (e.g., the touch sensor cross-talk compensation sub-block  52  may be implemented without the reference voltage cross-talk compensation sub-block  54  and vice versa). 
     To help illustrate the effects on pixel circuitry  60  that are rectified by the cross-talk compensation block  46 ,  FIG. 8  is a simplified schematic diagram of pixel circuitry  60 . The pixel circuitry  60  may be controlled by a data line voltage signal  62  (e.g., on data line  64 ), a scan control signal  66  (e.g., on scan line  68 ), and/or an emission control signal  70 . For example, the data line voltage signal  62  may be an analog voltage signal indicative of the compensated image data  58  (e.g., compensated pixel data of luminance values), and the scan control signal  66  may be a selection signal to access a specific pixel by operating one or more switching devices  72 . Additionally, the emission control signal  70  may connect or disconnect a light emissive element  74  (e.g., an organic or micro light emitting diode) of the pixel circuitry  60  and/or a reference voltage supply line  76 , for example, to disconnect the light emissive element  74  when a new data line voltage signal  62  is being written (e.g., programmed) to the pixel circuitry  60  and to connect the light emissive element  74  for illumination. 
     The switching devices  72  may be of any suitable type of electrical switch (e.g., p-type metal-oxide-semiconductor (PMOS) transistors, n-type metal-oxide-semiconductor (NMOS) transistors, etc.). In the depicted example, a storage capacitor  78  is coupled between the reference voltage supply line  76  (e.g., supplying the reference voltage  80 ) and an internal (e.g., current control) node  82 . Additionally, the voltage at the internal node  82  may control a gate  84  of a switching device  72 . The light emission from the light emissive element  74  may be varied based on the magnitude of electrical current supplied to the light emissive element  74 , which may be controlled by the voltage at the internal node  82  applied to the gate  84 . Moreover, the switching device  72  controlled by the gate  84  may be operated in its linear mode (e.g., region) such that its channel width and, thus, permitted current flow varies proportionally with the voltage of the internal node  82 . Thus, to facilitate controlling light emission, the data line voltage signal  62  may be used to set the voltage at the internal node  82  and, therefore, regulate the current flow from the reference voltage supply line  76 . 
     As one of ordinary skill would appreciate, deviations of the data line voltage signal  62  and/or the reference voltage  80  may change the luminance output of the light emissive element  74 . As such, compensation for cross-talk that causes such deviations may assist in reducing visible artifacts. 
     In further illustration, a schematic diagram of a portion of the display panel  40 , including the data lines  64  to the pixel circuitry  60 , is shown in  FIG. 9 . In some embodiments, the display panel  40  may use one or more digital to analog converters (DACs)  86  to convert the compensated image data  58 , which may be digitally represented, into the data line voltage signals  62  to be supplied to the pixel circuitry  60 . Moreover, in some embodiments, data line voltage signal output from the DACs  86  may be buffered by one or more buffers  88  (e.g., operational amplifiers), for example, to stabilize the signal under the current draw of the pixel circuitry  60  and/or column drivers  90 . The display panel  40  may include column drivers  90 , also known as data drivers and/or display drivers, including source latches  92 , source amplifiers  94 , and/or any other suitable logic/circuitry, to select the appropriate data line voltage signal  62  and apply the signal to the appropriate pixel circuitry  60  to achieve the target luminance output from the light emissive element  74 . 
     As the data line voltage signals  62  are run to their corresponding pixel circuitry  60  in the display panel  40 , touch sensor circuitry  100  may be closely layered on top of or integrated into the display panel  40  as part of a touch sensor sub-system  102 , as illustrated in  FIG. 10 . In some embodiments, a touch controller  104  may generate (e.g., via touch drive logic  106  and/or a touch drive interface  108 ) a touch stimulus signal  110  via an array of touch drive electrodes  112 . Touch sense electrodes  114  may form a grid of touch areas  116  (e.g., capacitive sensing nodes) with the touch drive electrodes  112  such that when an object, such as a finger, is located near the confluence of a given touch drive electrode  112  and a given touch sense electrode  114 , touch sense logic (e.g., via a touch sense interface  120 ) may determine a placement of the object on the grid of touch areas  116 . It should be noted that the terms “lines” and “electrodes” as used herein simply refers to conductive pathways, and is not intended to be limited to structures that are strictly linear. Rather, the terms “lines” and “electrodes” may encompass pathways that change direction, are of different size, shape, materials, and/or span multiple regions. 
     In general, a finger or object may disrupt the electromagnetic fields of the touch stimulus signal  110  in the touch area(s)  116  that the touch occurs. The change in the electromagnetic fields may be registered by the touch sense interface  120  via the touch sense electrodes  114  and processed via the touch sense logic  118 . The touch controller  104  may communicate an occurrence and/or position of user touches or hovers to the processor core complex  18 , and the touch may be correlated to what is displayed on the electronic display  12 . 
     As electronic devices get smaller, the cross-talk between the touch sensor circuitry  100  (e.g., the touch stimulus signal on the touch drive electrodes  112 ) and the pixel circuitry  60  may cause noticeable artifacts in the luminance output of the light emissive elements  74 . Additionally, increased magnitude of the touch stimulus signal, while possibly providing increased fidelity and/or functionality (e.g., multi-touch sensing), may increase the cross-talk with the pixel circuitry  60 .  FIG. 11  is a schematic diagram of touch sensor circuitry  100 , pixel circuitry  60 , and cross-talk  122  between them. In some embodiments, a touch layer  124  of the touch sensor circuitry  100  may be directly adjacent a display layer  126  of the pixel circuitry  60 . Alternatively, an intermediate layer  128  of material or circuitry may exist between the touch layer  124  and the display layer  126 . 
     In one embodiment, the cross-talk  122  may occur between the touch drive electrodes  112  and the data lines  64  causing deviations in the data line voltage signals  62 . Although illustrated as a capacitive cross-talk, it should be appreciated that the cross-talk may be of any type of electromagnetic interference. To reduce or eliminate perceivable effects of the cross-talk  122 , the touch sensor cross-talk compensation sub-block  52  may compensate the input image data  56  such that the data line voltage signal  62  is adjusted to obtain the desired voltage at the internal node  82  controlling the gate  84  to supply the desired current to the light emissive element  74 . 
     The touch drive logic  106  and/or touch drive interface  108  may generate and transmit the touch stimulus signal  110  to the touch drive electrodes  112 . Depending on the frequency of the touch stimulus signal  110 , the cross-talk  122  may manifest differently at different locations in the display layer  126 . In some embodiments, the cross-talk  122  from the touch layer  124  to the display layer  126  may result in a banded pattern  130  across the electronic display  12 , which may be dependent upon the frequency of the touch stimulus signal  110 , as depicted in  FIG. 12 .  FIG. 12  includes a sampling  132  of banded patterns  130  at different frequencies of the touch stimulus signal  110 . The banded pattern  130  may include portions of the electronic display  12  that have increased luminance  134  and portions of the electronic display  12  that have decreased luminance  136 . Moreover, the magnitude of the increase and/or the decrease in luminance may trend with the magnitude of the touch stimulus signal  110 . Furthermore, the spatial frequency of the banded pattern  130  may vary based on the frequency of the touch stimulus signal  110 . 
     In some embodiments, the touch sensor cross-talk compensation sub-block  52  may determine and apply a compensation to decrease the luminance of pixels in portions of the electronic display  12  that would otherwise have increased luminance  134  due to the cross-talk and increase the luminance of pixels in portions of the electronic display  12  that would otherwise have decreased luminance  136  due to the cross-talk. Spatially the touch sensor cross-talk compensation sub-block  52  may compensate the pixels of the electronic display with the inverse equivalent of the banded pattern  130  at the spatial frequency determined by the time frequency of the touch stimulus signal  110 . 
       FIG. 13  is a flowchart  140  of an example process for compensating image data for touch sensor cross-talk  122 . The process may include receiving, for example via the cross-talk compensation block  46 , input image data  56  (process block  142 ). The touch sensor cross-talk compensation sub-block  52  of the cross-talk compensation block  46  may determine the frequency and/or magnitude of the touch stimulus signal  110  (process block  144 ), and, based on the determined frequency and/or magnitude, spatially determine image data compensation values for the pixels of the electronic display  12  (process block  146 ). The touch sensor cross-talk compensation sub-block  52  may also apply the compensation to the input image data  56  (process block  148 ) and output the compensated image data  58  (process block  150 ). 
     Additionally or alternatively, cross-talk  122  may also occur within the pixel circuitry  60 , as illustrated in  FIG. 14 . In some embodiments, pixels may be updated with new data (e.g., for a new frame) by row. For example, multiple pixels in a column may share the same data line  64 , and in some embodiments, the pixels may be activated by row (e.g., via the scan control signal  66 ). However, cross-talk  122  may exist between the reference voltage supply line  76  and the data line  64 . When a first row is deactivated, and a second subsequent row is activated, the change in data line voltage signal  62  from the signal of a first pixel in the first row to the signal of a corresponding pixel in the second row may cause fluctuations in the reference voltage  80  on the reference voltage supply line  76  due to the cross-talk  122 , as shown in the graph  152  of  FIG. 15 . As such, larger changes in the data line voltage signal  62  may lead to larger deviations of the reference voltage  80 . The graph  152  illustrates the reaction  154  of the affected reference voltage  80 B to the change  156  in data line voltage signal  62  as compared to the ideal reference voltage  80 A. The intended voltage difference  158  between the data line voltage signal  62  and the ideal reference voltage  80 A may yield the desired luminance from the light emissive element  74 , but during the programming period  160  of the pixel, the affected reference voltage  80 B may not have time to settle before the programming period  160  ends. As such, the pixel may be provided a programmed voltage difference  162  that deviates from the intended voltage difference  158  with some amount of error  164 . In some scenarios, increased refresh rates (e.g., shorter programming periods  160 ) and/or higher density display panels  40  (e.g., higher resolution and/or smaller display panels  40  that may increase the magnitude of the cross-talk) may induce increased amounts of error  164 . As such, the compensation for such error may allow for increased refresh rates and higher resolution displays with reduced likelihood of visual artifacts. 
       FIG. 16  is a graph  166  of the uncompensated data line voltage signal  62 A and the compensated data line voltage signal  62 B relative to the ideal reference voltage  80 A and the affected reference voltage  80 B. In the depicted embodiment, the compensated data line voltage signal  62 B has been decreased by a compensation amount  168  approximately equal to the error  164 . As such, at the end of the programming period  160 , the compensated voltage difference  170  is approximately equal to the intended voltage difference  158 , such that the likelihood of visual artifacts due to the cross-talk  122  is reduced or eliminated. 
     As discussed above, the deviation in the reference voltage  80  due to cross-talk  122  with the data line  64  may vary based on the change in data line voltage signal  62  from the access of one row to the next. Furthermore, as depicted in  FIG. 14 , multiple data lines  64  may exhibit cross-talk with a single reference voltage supply line  76 . As such, the sharing of a reference voltage supply line  76  amongst multiple pixels may cause the reaction  154  of the reference voltage  80  to depend, at least partially, on the aggregate of the content transitions (e.g., changes in data line voltage signal  62 ) for a given row. Accordingly, in one embodiment, the reference voltage cross-talk compensation sub-block  54  may determine a difference between the previous data line voltage signal  62  (e.g., for a corresponding pixel in the same column and a previous row) and a current data line voltage signal  62  for each pixel of the current row and aggregate the changes. For example, if a first data line voltage signal  62  decreased, and a second data line voltage signal  62  increased, the variations in the reference voltage  80  due to cross-talk with the first and second data line voltage signals  62  may, at least partially, cancel. Moreover, in some embodiments the estimated error  164  for a given pixel may be determined by aggregation of the individual errors in reference voltage  80  caused by each change in the data line voltage signals  62  on the same row of the given pixel. Furthermore, in some embodiments, the estimated error for the given pixel may be determined by aggregating the individual errors in reference voltage  80  caused by the transitions (e.g., from content of a previous row to the current row) of other pixels in the proximity of the given pixel. For example, the individual errors in reference voltage  80  may be spatially averaged, such that transitions causing error in the reference voltage  80  occurring closer to the given pixel are weighted more heavily than transitions further from the given pixel. Additionally or alternatively, the data line voltage signal changes  156  may be aggregated via a spatial average and used to determine the estimated error  164 . 
     As discussed above, the transition from one row to the next may cause changes in the data line voltage signals  62 , which, in turn, may cause error in the reference voltage  80  due to the cross-talk  122 . Furthermore, in some embodiments, some rows (e.g., the first row of the electronic display  12 ) may not have a specific transition from a previous row. As such, to estimate the error in the reference voltage  80 , the reference voltage cross-talk compensation sub-block  54  may utilize a preset data line parking voltage as the previous data line voltage signal  62  to determine the change  156  in the data line voltage signal  62 . 
     In some embodiments, the changes in the reference voltage  80  due to changes in the data line voltage signal  62  may be determined via calibration using a set of test images to determine a mapping from the change in data line voltage signal  62  to the estimated change in reference voltage  80 . During compensation, the mapping may be implemented via an estimation equation or via a look-up-table. Using the mapping, the reference voltage cross-talk compensation sub-block  54  may estimate the error induced in the reference voltage  80  from each pixel transition and compute the total error for a given pixel by accumulating (e.g., via spatial averaging) the error induced by the pixels in proximity to the given pixel. Furthermore, in some embodiments, a threshold may be set such that changes  156  and/or a spatial average of multiple changes  156  less than the threshold are ignored. For example, changes  156  less than the threshold may be likely to not result in perceivable artifacts. As such, changes  156  less than the threshold may not be compensated, which may increase available bandwidth in the display pipeline  36 . 
       FIG. 17  is a flowchart  172  of an example process for compensating for cross-talk  122  between the reference voltage supply line  76  and the data lines  64 . The process may include receiving, for example via the reference voltage cross-talk compensation sub-block  54 , input image data  56  (process block  174 ) and determining changes in the data line voltage signal  62  from a previous row of pixels of the display panel  40  to the current row (process block  176 ). The reference voltage cross-talk compensation sub-block  54  may also estimate the error in the reference voltage  80  due to each change in the data line voltage signal  62  (process block  178 ). The error from each change in data line voltage signal  62  may be aggregated (process block  180 ). For example, the total error for a given pixel may be a spatial average of the errors from each change in data line voltage signals  62  in proximity to the given pixel. The reference voltage cross-talk compensation sub-block  54  may determine the compensation value (process block  182 ), for example based on the estimated error in the reference voltage  80  at each pixel. The compensation value may then be applied to the image data (process block  184 ) and the compensated image data  58  may be output (process block  186 ). 
     As discussed herein, by compensating for the cross-talk  122  between components of the pixel circuitry  60  and between the display layer  126  and the touch layer  124 , an electronic display may include a higher density of pixels (e.g., higher resolution), a faster refresh rate, a small form factor when layered with touch sensor circuitry  100 , increased magnitude of a touch stimulus signal  110  (e.g., for increased fidelity/functionality of a touch sensor sub-system  102 ), and exhibit a reduced likelihood of visual artifacts. Moreover, although the above referenced flowcharts  140  and  172  are shown in a given order, in certain embodiments, process blocks may be reordered, altered, deleted, and/or occur simultaneously. Additionally, the referenced flowcharts  140  and  172  are given as illustrative tools and further decision and process blocks may also be added depending on implementation. 
     The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure. 
     The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ,” it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Metadata:
Filing Date: 20200909
Publication Date: 20211221
Grant Date: 20211221
Priority Date: 20191018
Inventors: CHOI, MYUNGJOON
BRAHMA, KINGSUK
CHUO, LI-XUAN
JANGDA, MOHAMMAD ALI
KIM, HYUNSOO
NHO, HYUNWOO
PAI, ALEX H.
RICHMOND, JESSE AARON
RYU, JIE WON
SHEN, Shiping
WANG, CHAOHAO
Assignee: APPLE INC
CPC Classifications: [{"code": "G09G3/3275", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G3/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2320/0209", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2354/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0209", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0443", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2320/0209", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 75447120