PATENT DOCUMENT

Publication Number: US-10878747-B1
Application Number: US-201916506986-A
Country: US
Kind Code: B1

Title: Optical uniformity compensation

Abstract:
Methods and systems for compensating a display of an electronic device using internal sensing and external compensation. The external compensation uses a generated compensation map that then is used to compensate for variations that occur outside of display circuitry. The internal sensing compensation is used to compensate for internally sensed parameters (e.g., aging) of the display.

Claims:
What is claimed is: 
     
       1. A method comprising:
 retrieving one or more external compensation values from a compensation map for a display of an electronic device, wherein the one or more external compensation values are configured to compensate for one or more variations from one or more expected values associated with the display, wherein the one or more external compensation values are based on image data captured from outside of the electronic device, wherein the one or more external compensation values are configured to correct one or more non-uniform properties of the display comprising a curvature of a screen of the display at manufacture of the display; 
 applying the one or more external compensation values to input image data, thereby compensating the input image data for the one or more variations; 
 internally sensing a sensing current of an emissive element of the display internal to the electronic device based at least in part on the input image data after applying the one or more external compensation values to the input image data; 
 calculating a driving current compensation for the emissive element based at least in part on the sensing current and the one or more external compensation values; and 
 driving the emissive element based at least in part the driving current compensation. 
 
     
     
       2. The method of  claim 1 , wherein the one or more non-uniform properties of the display comprise a fine metal mask misalignment during manufacture of the display. 
     
     
       3. The method of  claim 1 , wherein internally sensing the sensing current is configured to offset one or more effects of aging on the emissive element. 
     
     
       4. The method of  claim 3 , wherein the emissive element comprises a self-emissive element. 
     
     
       5. The method of  claim 1 , wherein the compensation map is configured to compensate for the one or more variations at multiple temperatures. 
     
     
       6. The method of  claim 1 , wherein the one or more variations are captured using an image sensor. 
     
     
       7. The method of  claim 6 , wherein the image sensor comprises a camera or a photometer. 
     
     
       8. The method of  claim 1 , wherein the compensation map comprises a lower resolution than a resolution of the display. 
     
     
       9. Non-transitory, computer-readable, and tangible medium storing instructions thereon, that when executed, are configured to cause one or more processors to:
 retrieve one or more external compensation values from one or more generated compensation maps for a display of an electronic device storing the instructions, wherein the one or more external compensation values compensate for one or more variations from one or more expected values associated with the display, wherein the one or more external compensation values are determined based on image data captured from outside of the electronic device, wherein each of the one or more generated compensation maps comprises a lower resolution than a display resolution of the display, wherein the one or more external compensation values are configured to correct one or more non-uniform properties of the display comprising a fine metal mask misalignment during manufacture of the display; 
 apply the one or more external compensation values to input image data to compensate for the one or more variations; 
 after applying the one or more external compensation values to the input image data, internally sense a sensed parameter of an emissive element of the display internal to the electronic device; and 
 causing the emissive element to be driven based at least in part on a sensed parameter compensation that is based at least in part on the sensed parameter. 
 
     
     
       10. The non-transitory, computer-readable, and tangible medium of  claim 9 , wherein the instructions are configured to receive one or more linear scaling values and one or more constant scaling values that scale the input image data based at least in part on a brightness setting or gray level of the input image data. 
     
     
       11. The non-transitory, computer-readable, and tangible medium of  claim 9 , wherein the one or more generated compensation maps are divided into a linear parameter lookup table configured to store one or more gain factors to be applied based at least in part on the one or more variations and a constant parameter lookup table configured to store one or more offset values to be applied based at least in part on the one or more variations. 
     
     
       12. The non-transitory, computer-readable, and tangible medium of  claim 9 , wherein the instructions are configured to cause the one or more processors to up-sample the one or more generated compensation maps. 
     
     
       13. The non-transitory, computer-readable, and tangible medium of  claim 12 , wherein the instructions are configured to cause the one or more processors to smooth the one or more externally compensated values due to a resolution mismatch of the input image data and the one or more generated compensation maps. 
     
     
       14. The non-transitory, computer-readable, and tangible medium of  claim 9 , wherein the instructions are configured to cause the one or more processors to generate an indication of a reference parameter used in deriving the sensed parameter compensation. 
     
     
       15. The non-transitory, computer-readable, and tangible medium of  claim 9 , wherein the one or more non-uniform properties of the display comprises a curvature of the display at manufacture. 
     
     
       16. A system, comprising:
 a display having sensing circuitry configured to sense one or more parameters of the display during an off state of the display; 
 panel optical uniformity compensation (POUC) block circuitry comprising:
 a constant parameter adjustment configured to output offset image data based at least in part on received image data and a constant parameter map indicating an offset to be applied to the image data to be displayed on the display to at least partially offset a variation of an appearance of the display that is not internally sensed in the display, wherein the variation of the appearance of the display is based at least in part on a curvature of the display at manufacture or a fine metal mask misalignment during manufacture; and 
 a linear parameter adjustment configured to output externally compensated image data based at least in part on the offset image data and a linear parameter map, wherein the linear parameter map indicates a scaling factor to be applied to image data to be displayed on the display to at least partially offset the variation; and 
 
 a sensing loop configured to sense aging of the display from within the display using a sensing current and to apply aging compensation to the externally compensated image data. 
 
     
     
       17. The system of  claim 16 , comprising a processor, wherein the POUC block circuitry comprises instructions executed in the processor. 
     
     
       18. The system of  claim 16 , wherein the linear parameter map and the constant parameter map are generated based at least in part on one or more optical variations captured during manufacture of the display. 
     
     
       19. The system of  claim 16 , wherein the linear parameter map and the constant parameter map are generated for the display using another display representative of the display. 
     
     
       20. The system of  claim 16 , wherein the linear parameter adjustment and the constant parameter adjustment are based at least in part on at least one of a global brightness value and a temperature.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/696,970, entitled “Optical Uniformity Compensation,” filed on Jul. 12, 2018, which is incorporated herein by reference in its entirety for all purposes. 
    
    
     BACKGROUND 
     The present disclosure relates generally to techniques to sensing non-uniformity in a display. More specifically, the present disclosure relates generally to techniques for sensing and compensating for non-uniformity in a display. 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Electronic display panels are used in a plethora of electronic devices. These display panels typically include multiple pixels that emit light. The pixels may be formed using self-emissive units (e.g., light emitting diode) or pixels that utilize units that are backlit (e.g., liquid crystal display). The displays may be compensated for non-uniformity. However, sensing circuitry in the electronic device sensing for non-uniformity may detect some sources of non-uniformity and not detect other sources of non-uniformity. 
     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. 
     Display panel uniformity may be negatively impacted by various parameters (e.g., aging, curvature, aperture defects) of the display panel. The display panel uniformity may be improved by externally sensing non-uniformity properties in a display from outside the display panel (and its electronic device) during and/or after manufacture before use. The external sensing may detect and be used to compensate for static causes (e.g., screen curvature, aperture defects, etc.). The results of the initial external sensing may be stored in the device. However, the external sensing may be performed less frequently (e.g., only once) than is suitable to track dynamic causes (e.g., aging of the display). Instead, internal sensing may be used to track such changes more frequently than the external sensing. The internal and external sensing operations may be combined together to compensate the externally sensed constant causes and the internally sensed dynamic causes. 
    
    
     
       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 a display with sensing and compensation circuitry, in accordance with an embodiment; 
         FIG. 2  is one example of the electronic device of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 3  is another example of the electronic device of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 4  is another example of the electronic device of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 5  is another example of the electronic device of  FIG. 1 , in accordance with an embodiment of the present disclosure; 
         FIG. 6  illustrates a schematic diagram view of a unit pixel of the display of  FIG. 1 , in accordance with an embodiment; 
         FIG. 7  illustrates a block diagram of the display of  FIG. 1 , in accordance with an embodiment; 
         FIG. 8  illustrates an example emission map for the display of  FIG. 1 , in accordance with an embodiment; 
         FIG. 9  illustrates an example emission map of the display of  FIG. 1  due to misalignment of a fine metal mask during manufacture of the display, in accordance with an embodiment; 
         FIG. 10  illustrates a block diagram of circuitry that includes a panel optical uniformity compensation (POUC) block, in accordance with an embodiment; 
         FIG. 11  illustrates a block diagram view of the POUC block of  FIG. 10 , in accordance with an embodiment; 
         FIG. 12  illustrates a flow diagram view of a calibration process for the display of  FIG. 1 , in accordance with an embodiment; 
         FIG. 13  illustrates a block diagram view of a calibration system used to obtain compensation values for the display of  FIG. 1 , in accordance with an embodiment; and 
         FIG. 14  illustrates a flow diagram of a process for compensating driving of a display to account for variations in the display, 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. 
     Display panel uniformity can be improved by externally sensing non-uniformity properties or characteristics in a display at or around a time of manufacture of the electronic device. The external sensing may detect and be used to compensate for static causes (e.g., screen curvature, aperture defects, etc.) of the non-uniform display properties. The results of the initial external sensing may be stored in the device. However, the external sensing may be performed less frequently (e.g., only once) than is suitable to track dynamic causes (e.g., aging of the display). Instead, an internal sensing circuit may be used to track such changes more frequently than the external sensing. The internal and external sensing operations may be combined together to compensate the externally sensed constant causes and the internally sensed dynamic causes by passing the results of the external sensing to the internal sensing circuit that causing cumulative compensation for non-uniformity properties (e.g., luminance, color) detected using the external and internal sensing results. 
     A general description of suitable electronic devices that may include a self-emissive display, such as an LED (e.g., an OLED) display, and corresponding circuitry of this disclosure are provided. To help illustrate, an electronic device  10  including 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 computer, a mobile phone, a portable media device, a tablet, a television, a virtual-reality headset, a vehicle dashboard, and the like. Thus, it should be noted that  FIG. 1  is merely an 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 , one or more input device(s)  14 , one or more input/output (I/O) ports  16 , a processor core complex  18  having one or more processor(s) or processor cores, local memory  20 , main memory storage device(s)  22 , a network interface  24 , a power source  25 , and compensation circuitry  26 . 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, in some embodiments, 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  26  (e.g., a graphics processing unit (GPU)) may be at least partially included in the processor core complex  18  and/or the display. 
     Using pixels containing LEDs (e.g., OLEDs), the display  12  may show images. The display  12  may include touchscreen functionality for users to interact with a user interface appearing on the display  12 . The display  12  may include sensing circuitry  13  that is used to sense non-uniformity of the display  12  by sensing changes in one or more parameters (e.g., voltage/current) through thin-film transistors (TFTs) and/or emissive elements in the display  12 . 
     The sensing circuitry  13  may utilize inputs from the compensation circuitry  24  that stores and compensates for externally sensed non-uniformity. In some embodiments, functions of the compensation circuitry  26  may be embodied in the processor core complex  12 . Similarly, in certain embodiments, the compensation circuitry  26  may store the compensation values in the storage device(s)  22  and/or locally within the compensation circuitry  26 . The inputs from the compensation circuitry  26  to the sensing circuitry  13  may include compensated image data that compensates image data for externally sensed non-uniformity. Additionally or alternatively, the inputs from the compensation circuitry  26  to the sensing circuitry  13  may include a reference current that is utilized by the sensing circuitry  13  to internally sense non-uniformity in the display  12  (e.g., aging of TFTs and/or emissive elements). 
     As depicted, the processor core complex  18  is operably coupled to the local memory  20  and the main memory storage device(s)  22 . Thus, 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 and/or transmitting 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. Furthermore, as previously noted, the processor core complex  18  may include one or more separate processing logical cores that each process data according to executable instructions. 
     In addition to the executable instructions, the local memory  20  and/or the main memory storage device  22  may store the data to be processed by the cores of the processor core complex  18 . Thus, in some embodiments, the local memory  20  and/or the main memory storage device  22  may include one or more tangible, non-transitory, computer-readable media. 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 the like. 
     As depicted, the processor core complex  18  is also operably coupled to the network interface  24 . In some embodiments, the network interface  24  may facilitate communicating data with other electronic devices via network connections. For example, the network interface  24  (e.g., a radio frequency system) may enable the electronic device  10  to communicatively couple 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. 
     Additionally, as depicted, the processor core complex  18  is operably coupled to the power source  25 . In some embodiments, the power source  25  may provide electrical power to one or more component in the electronic device  10 , such as the processor core complex  18  and/or the electronic display  12 . Thus, the power source  25  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 to the I/O ports  16 . In some embodiments, the I/O ports  16  may enable the electronic device  10  to receive input data and/or output data using port connections. For example, a portable storage device may be connected to an I/O port  16  (e.g., universal serial bus (USB)), thereby enabling the processor core complex  18  to communicate data with the portable storage device. 
     As depicted, the electronic device  10  is also operably coupled to input devices  14 . In some embodiments, the input device  14  may facilitate user interaction with the electronic device  10  by receiving user inputs. For example, the input devices  14  may include one or more buttons, keyboards, mice, trackpads, microphones, and/or the like. Additionally, in some embodiments, the input devices  14  may include touch-sensing components in the electronic display  12 . In such embodiments, the touch sensing components may receive user inputs by detecting occurrence and/or position of an object touching the surface of the electronic display  12 . 
     In addition to enabling user inputs, the electronic display  12  may include a display panel with one or more display pixels. As described above, the electronic display  12  may control light emission from the display pixels to present visual representations of information, such as a graphical user interface (GUI) of an operating system, an application interface, a still image, or video content, by display image frames based at least in part on corresponding image data. In some embodiments, the electronic display  12  may be a display using liquid crystal display (LCD), a self-emissive display, such as an organic light-emitting diode (OLED) display, or the like. Moreover, in some embodiments, the electronic display  12  may refresh display of an image and/or an image frame, for example, at 60 Hz (corresponding to refreshing 60 frames per second), 120 Hz (corresponding to refreshing 120 frames per second), and/or 240 Hz (corresponding to refreshing 240 frames per second). 
     As depicted, the electronic display  12  is operably coupled to the processor core complex  18  and the image processing circuitry  26 . In this manner, the electronic display  12  may display image frames based at least in part on image data generated by the processor core complex  18  and/or the image processing circuitry  26 . Additionally or alternatively, the electronic display  12  may display image frames based at least in part on image data received via the network interface  24  and/or the I/O ports  16 . 
     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  surrounds 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 a touch-sensing component of the electronic display  12 , an application program may launch. 
     Furthermore, as depicted, input devices  14  may extend 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 an audio jack to connect to external devices. In some embodiments, the I/O ports  16  may include a speaker that outputs sounds from the handheld device  10 A and/or a microphone that captures sounds at the handheld device  10 A. 
     To further illustrate an 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 device  10 D, is shown in  FIG. 5 . For illustrative purposes, the wearable device  10 D may be any APPLE WATCH® model available from Apple Inc. As depicted, the tablet device  10 B, the computer  10 C, and the wearable device  10 D each also includes an electronic display  12 , input devices  14 , and an enclosure  28 . 
     Although the following discusses sensing current through an OLED as a pixel, some embodiments may include measuring other parameters suitable for other pixel types. For example, voltage may be sensed at LED/LCD pixels in the display. 
       FIG. 6  illustrates a schematic diagram of a pixel  100  that includes an emissive element  102 . The pixel  100  also includes a transistor  104  (e.g., TFT) that controls whether the pixel  100  is in an emissive or sensing state. In the emissive state, the transistor  104  directs an emissive current  106  through the emissive element  102  to emit light from the emissive element. In the sensing state, the transistor  104  directs voltages to create a sensing current  108 . 
     An amount of the current determines luminance of the emissive element  102  is based at least in part on a data voltage  110 . The data voltage  110  creates a voltage differential across a capacitor  112  that is equivalent to a gate-to-source voltage (VGs) of a transistor  114  that also sets a level of a reference voltage  116 . Differences in the transistor  104  and/or transistors  114  may impact driving conditions of the emissive element  102  potentially causing non-uniformity of different pixels in the display  12 . Furthermore, emission elements  102  of different pixels may have different emission efficiencies that may also cause different luminance levels of different pixels using a same driving current. 
     The display  12  may also be subject to other causes of non-uniformity. For example, as illustrated in  FIG. 7 , the display  12  may include a surface layer  120 . The surface layer  120  may include an enclosure of the display  12  that has a substantially flat portion  122  that and curved portions  124 . The surface layer  120  is located atop a display stack-up  126  (e.g., array of pixels  100 ). Light emitted from emissive elements  102  under the curved portions  124  may exit the surface layer  120  differently than light emitted from emissive elements  102  under the substantially flat portion  122 . For example,  FIG. 8  shows an emission map  130  that may result from having a surface layer  120  that has the substantially flat portion  122  and the curved portions  124 . As illustrated, light emitted in a flat zone  132  corresponding to the substantially flat portion  122  is substantially homogenous within the flat zone  132  but may be non-uniform with respect to light emitted (e.g., luminance, brightness) in a curved zone  134  at edges of the display  12 . The non-uniformity properties may include a percentage change of output luminance of light in the curved zone  134  relative to the flat zone  132 , a constant change of output luminance of light in the curved zone  134  relative to the flat zone  132 , and/or may include color changes of light emitted in the curved zone  134  relative to the flat zone  132 . Since these changes occur independent of what is occurring in the display stack-up  126  (i.e., has no effect on the sensing current  108 ), internal sensing using the sensing circuitry  13  may not be able to detect the non-uniformity attributable to the surface layer  120 . 
     The display  12  may also be subject to device aperture non-uniformity. For example, the display  12  may utilize one or more production components (e.g., a fine metal mask (FMM)) that may enable production and/or use of the display stack-up  126 . However, the production components and/or their applications may lead to variations (e.g., due to misalignment of the FMM) from a design of the display stack-up  126 . For example, a variation of a shape/size of an aperture of the FMM used to produce the display stack-up  126  may lead to more or less light being emitted from a respective portion of the display stack-up  126  corresponding to the aperture. This variation, when uncompensated for, may result in color drift and/or brightness variations in emitted light from the respective portion of the display  12 . For example,  FIG. 9  illustrates an emission map  140  that may result from a misaligned FMM for at least one color (e.g., red) of the display stack-up  126 . As illustrated, the emission map  140  shows a portion  142  that includes a color/brightness variation. Furthermore, since these variations may be independent of the sensing current  108 , internal sensing using the sensing circuitry  13  may not be able to detect the non-uniformity attributable to the surface layer  120 . 
     Since the light emission variations due to curvature of the surface layer  120 , aperture variations, and/or other artifacts may be undetectable via internal sensing, other sensing (e.g., external sensing) may be performed to detect such light emission variations. The other sensing (e.g., external sensing) may provide information that may enable the compensation circuitry  26 , the sensing circuitry  13 , or other suitable component to compensate for the various features (e.g., curvature) of the display  12  that may result in non-uniform properties of the display  12 . For instance,  FIG. 10  illustrates an embodiment of a block diagram of circuitry  150  that includes first compensation portion  152  (e.g., compensation circuitry  26 ) and a second compensation portion  154  (e.g., sensing circuitry  13 ). For example, the first compensation portion  152  may be used to implement compensation based at least in part on externally sensed variations, and the second compensation portion  154  may be used to implement looping compensation based on internally sensed variations. Furthermore, in some embodiments, the internal sensing may be iterated through a loop repeatedly compensating for such internally sensed variations. 
     The circuitry  150  receives input image data  156  that is then processed using color/content processing circuitry  158  that processes the input image data  156  for color and content. For example, the color/content processing circuitry  158  may set various parameters (e.g., tint, contrast, etc.) of image data for each image frame using one or more settings (e.g., user settings). The processed image data is then compensated using the first compensation portion  152  and the second compensation portion  154 . As illustrated, the first compensation portion  152  may include a generated compensation map  160 . The generated compensation map  160  may be stored in the storage device(s)  22 , or any other suitable medium. The generated compensation map  160  may be loaded from the storage device(s)  22  when the display  12  and/or the electronic device  10  are powered on. The generated compensation map  160  may be generated using one or more externally captured emission maps that captures deviations from expected outputs and may be used by panel optical uniformity compensation (POUC) block circuitry  162  to compensate for the captured deviations. The POUC block circuitry  162  may be implemented using dedicated hardware, instructions executed by the processor(s)/processor core complex  12  and/or other data processing circuitry, or a combination thereof. For example, the generated compensation map  160  may compensate for image data variations for a variety of different temperatures for the display  12 . 
     The POUC block circuitry  162  may be located in a display pipeline to apply compensation to each image frame to be displayed on the display  12 . The POUC block circuitry  162  then passes externally compensated image data  163  to the second compensation portion  154 . Specifically, the externally compensated image data  163  is passed to electrical compensation circuitry for driving current  164  to perform compensation of a driving current using internally sensed values  165  from electrical sensing circuitry for driving current  166  that senses the internally sensed values  165  from a panel  168 . The electrical sensing circuitry for driving current  166  and the POUC block circuitry  162  may both utilize one or more parameters  167 , and therefore, may share such parameters. For example, the one or more parameters  167  may include temperature and/or other parameters that may be used to determine compensation values in both the first compensation portion  152  and the second compensation portion  154 . Additionally or alternatively, the one or more parameters  167  may be generated by the POUC block circuitry  162  or the electrical sensing circuitry for driving current  166  and used by the other. 
       FIG. 11  illustrates a block diagram of an embodiment of the POUC block circuitry  162 . In some embodiments, the POUC block circuitry  162  may be implemented in the processor(s)/processor core complex  12 , compensation circuitry  26 , or the like. For example, the POUC block circuitry  162  may be implemented in a CPU, a GPU, and/or a display controller for the display  12 . The POUC block circuitry  162  may include a linear scaling lookup table (LUT)  170  and a constant scaling LUT  172  that may be used to adjust optical compensation information according to brightness settings and image contents. The linear scaling LUT  170  may be applied as a gain while the constant scaling LUT  172  may be applied as an offset. Similarly, data from the generated compensation map  160  may be bifurcated into a linear parameter map  174  and a constant parameter map  176 . In some embodiments, to save storage space and/or processing, the linear parameter map  174  and/or the constant parameter map  176  may not store information for each individual pixel in the display  12  as map(s) of lower resolution of which the display  12  is capable. Instead, the POUC block circuitry  162  may utilize up-samplers  178  to upconvert the data from the linear parameter map  174  and/or the constant parameter map  176 . 
     The values from the constant scaling LUT  172  and the constant parameter map  176  are passed to constant parameter adjustment circuitry  180  to apply offset factors from the constant scaling LUT  172  and the constant parameter map  176  to the input image data  156  to form offset input data  182 . Similarly, the values from the linear scaling LUT  170  and the linear parameter map  174  are passed to linear parameter adjustment circuitry  184  that applies the gain factors from the linear scaling LUT  170  and the linear parameter map  174  to the offset input data  182  to generate gained input data  186 . A global brightness setting (DBV)  188  and a temperature  190  may be used by constant parameter adjustment circuitry  180  and the linear parameter adjustment circuitry  184  to generate the offset input data  182  and the gained input data  186 . In other words, the offset input data  182  may be based at least in part on the input image data  156 , the constant scaling LUT  172 , the constant parameter map  176 , the DBV  188 , and the temperature  190 . 
     In some embodiments, low-resolution maps upconverted using up-samplers  178  may cause some artifacts. Accordingly, the POUC block circuitry  162  may include data smoothing  192  that smooths the gained input data  186  to reduce/remove such artifacts from the externally compensated image data  163 . For example, the smoothing may include dithering, interpolation, and/or filtering to smooth between regions of the low-resolution maps. 
     The POUC block circuitry  162  may also include reference map extraction circuitry  194  that generates a reference current  196  that is passed (e.g., as the one or more parameters  167 ) to the electrical sensing circuitry for driving current  166 . The reference current  196  is used by the electrical sensing circuitry for driving current  166  as a baseline to start with rather than assuming an ideal current. In other words, the reference current  196  enables the electrical sensing circuitry for driving current  166  to quickly refine the driving current properly. 
       FIG. 12  illustrates a flow diagram  200  of a calibration process that may be performed during or after manufacture of the display  12  in accordance with the embodiments described herein. A non-compensated panel  202  is submitted to external electrical sensing that electrically senses values in the non-compensated panel  202  (block  204 ). The panel then undergoes color adjustment based on the external electrical sensing (block  206 ). Then, an appearance of the display  12  is externally and optically captured for use by the POUC block circuitry  162  (block  208 ). This optical capture is used to generate the generated compensation map  160  that is used by the POUC block circuitry  162 . In some embodiments, the optical capture may be captured at multiple temperatures. Furthermore, in certain embodiments, each panel may be individually tested. Additionally or alternatively, a panel may be used to represent multiple panels as a representative sample. Thus, a single panel may be used to represent a batch of panels. 
       FIG. 13  illustrates a block diagram of a capture system  220 . The capture system  220  includes a computing device  222  that utilizes a display controller  224  to control a panel  226  under testing. For instance, the computing device  222  may instruct the display controller  224  to cause the panel  226  to display a calibration image that is captured by an image sensor  228 . For example, the image sensor  228  may include a high-resolution imaging capture device, such as a camera or a photometer. In some embodiments, the panel  226  may be tested under multiple temperatures using a temperature control  230 . For instance, the temperature control  230  may include heating elements that change a temperature of the panel  226  under testing. Furthermore, in some embodiments, the image sensor  228  and the panel  226  may have a fixed relative position in a capture fixture  232  that enables rapid successive testing of multiple panels  226 . 
       FIG. 14  is a flow diagram of a process  260  for adjusting certain parameters (e.g., driving current) of various pixels  100  to present image data with more uniform properties across the display  12 . The process  260  may include storing external compensation values in a generated compensation map  160  for the display  12  (block  262 ). The external compensation values compensate for variations from expected values captured from outside of the electronic device  10 . The generated compensation map  160  may be stored in the storage device(s)  22  or other suitable medium. The generated compensation map  160  may include multiple sub-maps. For example, each sub-map may correspond to various values of a parameter (e.g., temperature, global brightness setting, etc.). The generated compensation map  160  may be used to compensate for artifacts that are not detectable using internal sensing. For example, the artifacts may be attributed to curvature of a screen of the display  12 , fine metal mask misalignment, and/or other factors. 
     The processor(s)/processor core complex  12  then applies the external compensation values using the POUC block circuitry  162  to compensate for the externally captured variations (block  264 ). The POUC block circuitry  162  may include dedicated circuitry and/or the processor(s)/processor core complex  12  implementing specific software instructions from the storage device(s)  22  or other suitable medium. After applying the external compensation values, the processor(s)/processor core complex  12  internally senses a sensing current of the emissive element  102  (block  266 ). Based at least in part on the sensing current, the processor(s)/processor core complex  12  calculates a driving current compensation for the emissive element  102  (block  268 ). The sensing current may be indicative of aging of the display  12 , and the calculated driving current may compensation for aging of the display  12 . The processor(s)/processor core complex  12  then cause the emissive element  102  to be driven based at least in part on image data and the driving current (block  270 ). 
     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. Furthermore, it should be further understood that each of the embodiments disclosed above may be used with any and all of the other embodiments disclosed herein. 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: 20190709
Publication Date: 20201229
Grant Date: 20201229
Priority Date: 20180712
Inventors: GAO, SHENGKUI
WANG, CHAOHAO
LIN, HUNG SHENG
KIM, HYUNSOO
NHO, HYUNWOO
HWANG, INJAE
RICHMOND, JESSE AARON
RYU, JIE WON
TAN, JUNHUA
BRAHMA, KINGSUK
CHO, Myung-Je
CHOI, MYUNGJOON
SHEN, Shiping
CHANG, SUN-IL
YAO, WEI H.
QIAO, YI
Assignee: APPLE INC
CPC Classifications: [{"code": "G09G5/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2320/0285", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/3233", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/006", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2320/0233", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2330/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0242", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/043", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2340/0407", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G5/39", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2320/041", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G5/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/3216", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2320/041", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2340/0407", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/043", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G5/39", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/3216", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G5/003", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 74039647