Patent Publication Number: US-11386839-B2

Title: Systems and methods for management of organic light-emitting diode display degradation

Description:
TECHNICAL FIELD 
     The present disclosure relates in general to information handling systems, and more particularly to managing degradation of organic light-emitting diode displays in an information handling system. 
     BACKGROUND 
     As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. 
     Organic light-emitting diode (OLED) displays are increasing in use in information handling systems, televisions, and other video display applications, due to their advantages over more traditional liquid crystal displays. An OLED display, in contrast to a liquid crystal display, operates without a backlight because it emits visible light. Thus, it can display deep black levels and may be thinner and lighter than a liquid crystal display. In low ambient light conditions (e.g., such as a dark room), an OLED screen may achieve a higher contrast ratio than a liquid crystal display. 
     However, due to the thinner designs of OLED displays, localized thermal conditions within an OLED display may lead to non-homogenous degradation of the OLED display, with some portions suffering a greater loss in luminosity than other portions of the OLED display. Further, when displaying different colors, due to the emissive nature of OLEDs, some colors (e.g., blue) may degrade more than others (e.g., red). 
     SUMMARY 
     In accordance with the teachings of the present disclosure, one or more disadvantages and problems associated with managing degradation of organic light-emitting diode displays may be reduced or eliminated. 
     In accordance with embodiments of the present disclosure, an information handling system may include a display comprising an organic light-emitting diode (OLED) panel and an OLED degradation management subsystem configured to, responsive to a condition for initiating a calibration of the OLED panel, logically divide the OLED panel into a plurality of non-overlapping test windows of a defined size, measure a physical quantity for a pixel of at least one of the plurality of non-overlapping test windows to determine a deviation of the at least one test window from a linear degradation profile, and correct for non-linear degradation occurring in the at least one test window based on the deviation. 
     In accordance with these and other embodiments of the present disclosure, a method may include logically dividing an organic light-emitting diode (OLED) panel into a plurality of non-overlapping test windows of a defined size, measuring a physical quantity for a pixel of at least one of the plurality of non-overlapping test windows to determine a deviation of the at least one test window from a linear degradation profile, and correcting for non-linear degradation occurring in the at least one test window based on the deviation. 
     In accordance with these and other embodiments of the present disclosure, an article of manufacture may include a non-transitory computer-readable medium and computer-executable instructions carried on the computer-readable medium, the instructions readable by a processor, the instructions, when read and executed, for causing the processor to, logically divide an organic light-emitting diode (OLED) panel into a plurality of non-overlapping test windows of a defined size, measure a physical quantity for a pixel of at least one of the plurality of non-overlapping test windows to determine a deviation of the at least one test window from a linear degradation profile, and correct for non-linear degradation occurring in the at least one test window based on the deviation. 
     Technical advantages of the present disclosure may be readily apparent to one skilled in the art from the figures, description and claims included herein. The objects and advantages of the embodiments will be realized and achieved at least by the elements, features, and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are examples and explanatory and are not restrictive of the claims set forth in this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein: 
         FIG. 1  illustrates a block diagram of an example information handling system, in accordance with certain embodiments of the present disclosure; 
         FIG. 2  illustrates an example graph of luminosity versus time over an expected life span of an OLED panel for two different pixels of the OLED panel, in accordance with embodiments of the present disclosure; 
         FIG. 3  illustrates a block diagram of selected components that may be used for degradation management of an OLED panel, in accordance with embodiments of the present disclosure; and 
         FIG. 4  illustrates a flow chart of an example method for management of degradation of an OLED panel, in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Preferred embodiments and their advantages are best understood by reference to  FIGS. 1 through 4 , wherein like numbers are used to indicate like and corresponding parts. 
     For the purposes of this disclosure, an information handling system may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, entertainment, or other purposes. For example, an information handling system may be a personal computer, a personal digital assistant (PDA), a consumer electronic device, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include memory, one or more processing resources such as a central processing unit (“CPU”) or hardware or software control logic. Additional components of the information handling system may include one or more storage devices, one or more communications ports for communicating with external devices as well as various input/output (“I/O”) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communication between the various hardware components. 
     For the purposes of this disclosure, computer-readable media may include any instrumentality or aggregation of instrumentalities that may retain data and/or instructions for a period of time. Computer-readable media may include, without limitation, storage media such as a direct access storage device (e.g., a hard disk drive or floppy disk), a sequential access storage device (e.g., a tape disk drive), compact disk, CD-ROM, DVD, random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), and/or flash memory; as well as communications media such as wires, optical fibers, microwaves, radio waves, and other electromagnetic and/or optical carriers; and/or any combination of the foregoing. 
     For the purposes of this disclosure, information handling resources may broadly refer to any component system, device or apparatus of an information handling system, including without limitation processors, service processors, basic input/output systems (BIOSs), buses, memories, I/O devices and/or interfaces, storage resources, network interfaces, motherboards, and/or any other components and/or elements of an information handling system. 
       FIG. 1  illustrates a block diagram of an example information handling system  102 , in accordance with embodiments of the present disclosure. In some embodiments, information handling system  102  may be a mobile device sized and shaped to be readily transported and carried on a person of a user of information handling system  102  (e.g., a notebook or laptop computer, etc.). As depicted in  FIG. 1 , information handling system  102  may include a processor  103 , a memory  104  communicatively coupled to processor  103 , a battery  106 , an alternating current (AC) source  107 , a power interface  108 , a display  109 , and a voltage regulator tree  110 . 
     Processor  103  may include any system, device, or apparatus configured to interpret and/or execute program instructions and/or process data, and may include, without limitation, a microprocessor, microcontroller, digital signal processor (DSP), application specific integrated circuit (ASIC), or any other digital or analog circuitry configured to interpret and/or execute program instructions and/or process data. In some embodiments, processor  103  may interpret and/or execute program instructions and/or process data stored in memory  104  and/or another component of information handling system  102 . 
     Memory  104  may be communicatively coupled to processor  103  and may include any system, device, or apparatus configured to retain program instructions and/or data for a period of time (e.g., computer-readable media). Memory  104  may include RAM, EEPROM, a PCMCIA card, flash memory, magnetic storage, opto-magnetic storage, or any suitable selection and/or array of volatile or non-volatile memory that retains data after power to information handling system  102  is turned off. 
     As shown in  FIG. 1 , memory  104  may have stored thereon an OLED degradation manager  118 . OLED degradation manager  118  may comprise a program of instructions that may be read and executed by processor  103  to perform management of OLED controller  120  and/or OLED panel  116  to determine a level of degradation of certain portions of OLED panel  116  and to correct for such degradation. In particular, OLED degradation manager  118  may employ a linear model that assumes a linear degradation of individual OLEDs of OLED panel  116  over time, but also corrects such linear adaptation to account for non-linear degradation, as described in greater detail below. In some embodiments, OLED degradation manager  118  may be implemented in firmware or a display driver of display  109 . In other embodiments, OLED degradation manager  118  may be implemented as an application configured to execute within an operating system of information handling system  102 . 
     Battery  106  may comprise any system, device, or apparatus configured to store energy which may be used by information handling system  102  to power components of information handling system  102  to perform the functionality thereof. In some embodiments, battery  106  may comprise an electrochemical cell configured to convert stored chemical energy into electrical energy. 
     AC source  107  may comprise any system, device, or apparatus configured to provide a direct current (DC) power source derived from an AC power source (e.g., an AC adapter configured to receive an AC input and convert such AC input to a DC voltage). 
     Power interface  108  may comprise any system, device, or apparatus configured to serve as an electrical interface between power sources (e.g., battery  106  and AC source  107 ) and voltage regulator tree  110 . Accordingly, power interface  108  may include any suitable combination of connectors, cabling, cabling harnesses, and/or other components to provide such an electrical interface. In some embodiments, power interface  108  may be configured to, when an AC input is present, output a voltage V PWR  which is provided by AC source  107 , and when an AC input is not present, output a voltage V PWR  which is provided by battery  106 , in order to provide electrical energy to components of information handling system  102 . 
     Display  109  may comprise any instrumentality or aggregation of instrumentalities by which a user may interact with information handling system  102 . For example, display  109  may permit a user to input data and/or instructions into information handling system  102 , and/or otherwise manipulate information handling system  102  and its associated components. Display  109  may also permit information handling system  102  to communicate data to a user, e.g., by way of a display device. In some embodiments, display  109  may comprise a touch-screen display. When implemented as a touch-screen display, display  109  may comprise touch sensor  112 , touch sensor controller  114 , OLED panel  116 , and LED controller  120 . 
     As known in the art, touch sensor  112  may include any system, device, or apparatus configured to detect tactile touches (e.g., by a human finger, a stylus, etc.) on touch sensor  112  and generate one or more signals indicative of the occurrence of such touches and/or the locations of such touches on the touch sensor  112 . In some embodiments, touch sensor  112  may be a capacitive touch sensor configured to detect changes in capacitance induced by tactile touches. In these and other embodiments, touch sensor  112  may be constructed from substantially optically transparent material and placed over OLED panel  116  or another display apparatus, allowing a user to view graphical elements of the touch display while interacting with touch sensor  112 . 
     Touch sensor controller  114  may be communicatively coupled between touch sensor  112  and processor  103 , and comprise any system, device, or apparatus configured to process signals indicative of touches received from touch sensor  112  and translate such signals into signals which may be processed by processor  103 . In addition, touch sensor controller  114  may control one or more operating conditions associated with touch sensor  112 , including the rate of sampling touches, whether touch sensor  112  is powered on or enabled, and/or other operating conditions. 
     OLED panel  116  may comprise any suitable system, device, or apparatus configured to display human-perceptible graphical data and/or alphanumeric data to display  109 . As is known in the art, OLED panel  116  may include an array of light-emitting diodes (LED), wherein each LED comprises an emissive electroluminescent layer which is a film of organic compound that emits light in response to an electric current. 
     OLED controller  120  may be communicatively coupled between OLED panel  116  and processor  103 , and may comprise any system, device, or apparatus configured to, based on graphical data communicated from processor  103  to OLED controller  120 , control individual LEDs of OLED panel  116  in order to display graphical data and/or alphanumeric data on OLED panel  116 . 
     Voltage regulator tree  110  may comprise any suitable system, device, or apparatus configured to receive a voltage as an input, and generate from such voltage one or more regulated output voltages to power components of information handling system  102  that may have varying input voltage requirements from each other. Accordingly, voltage regulator tree  110  may include one or more direct current-to-direct current voltage converters, including without limitation one or more buck converters, one or more buck-boost converters, and one or more boost converters. 
     In addition to processor  103 , memory  104 , battery  106 , interface  108 , display  109 , and voltage regulator tree  110 , information handling system  102  may include one or more other information handling resources. An information handling resource may include any component, system, device or apparatus of an information handling system, including without limitation, a processor (e.g., processor  103 ), bus, memory (e.g., memory  104 ), I/O device and/or interface, storage resource (e.g., hard disk drives), network interface, electro-mechanical device (e.g., fan), display, power supply, and/or any portion thereof. 
     In operation, OLED degradation manager  118  may, at defined instances of time, perform a calibration operation wherein OLED panel  116  is divided into a plurality of non-overlapping test windows (e.g., 120 pixels by 120 pixels, 40 pixels by 40 pixels) much smaller than the resolution of OLED panel  116 . During the calibration operation, OLED degradation manager  118  may measure a physical quantity (e.g., pixel luminosity) for a pixel of each test window (e.g., bottom-right pixel, randomly-selected pixel, etc.), to determine the test window&#39;s deviation, if any, from a linear degradation profile. OLED degradation manager  118  may further correct for the deviation by correcting the linear adaption for each test window. For example, OLED degradation manager  118  may modify a frame buffer for display data to brighten or darken certain areas of an image to account for the non-linear degradation, or may control brightness of OLED panel  116  (e.g., via OLED controller  120 ), such that each test window of OLED panel  116  displays in accordance with its own brightness level. 
     To illustrate,  FIG. 2  illustrates an example graph of luminosity versus time over an expected life span of OLED panel  116  for two different pixels of OLED panel, in accordance with embodiments of the present disclosure. For example, the solid-line graph may represent luminosity over time for a center pixel of OLED panel  116  while the dashed-line graph may represent luminosity over time for a bottom left corner pixel of OLED panel  116 . As shown in  FIG. 2 , over the lifetime of OLED panel  116 , the pixel represented by the dashed-line graph may experience more degradation due to temperature and/or other effects. Accordingly, OLED degradation manager  118  may correct for such non-homogenous degradation by applying different corrections to the respective test windows comprising the pixel represented by the dashed-line graph and the pixel represented by the solid-line graph. 
     Further, as shown in  FIG. 2 , degradation of pixels may be highly non-linear, and in some cases, as indicated by circles in  FIG. 2 , may be non-monotonic with respect to time, with periods of time in which luminosity may increase before again decreasing. Accordingly, existing approaches which assume linear degradation do not accurately track actual degradation, and thus attempts by existing approaches to correct for degradation based on an assumption of linear degradation will fail to correct for such non-linearities and non-monoticities. However, OLED degradation manager  118  may correct for such non-linearities by applying corrections over time that make it appear to a user of OLED panel  116  that degradation is occurring linearly with respect to time. 
     In some instances, the sizes of test windows may be reduced over the lifetime of display  109 , to increase image granularity used to perform calibration over the lifetime of display  109 . 
     The defined instances of time in which OLED degradation manager  118  may initiate a calibration may be defined in any suitable manner, including on a periodic basis (e.g., every three months). In addition to or in lieu of performing calibrations on a periodic basis, OLED degradation manager  118  may limit calibrations to times in which particular conditions are present. For example, due to the fact that calibrations may use significant processing resources, OLED degradation manager  118  may limit calibrations to times at which the workload of processor  103  is below a threshold level. Also, to prevent calibration from consuming limited energy from battery  106 , OLED degradation manager  118  may limit calibrations to times at which components of information handling system  102  are powered from AC source  107 . Further, to ensure OLED degradation manager  118  performs calibration based on representative physical characteristics of OLED panel  116 , OLED degradation manager  118  may limit calibrations to times at which particular applications (e.g., those with higher levels of graphics acceleration) are executing on processor  103 . 
     In these and other embodiments, only particular test windows may be calibrated. For instance, OLED degradation manager  118  may use telemetry data to identify a set of test windows that are proximate to sources of heat in OLED panel  116  and/or are used more frequently than other test windows in displaying images, and limit calibration to those identified sets of test windows. Thus, in some embodiments, OLED degradation manager  118  may calibrate all test windows on a regular periodic basis (e.g., once every three months) but may calibrate particular identified test windows that may be more susceptible to degradation (e.g., those test windows having frequently-used pixels and/or are proximate to heat sources) on a more frequent basis. 
     In these or other embodiments, OLED degradation manager  118  may at times perform dynamic derating of OLED panel  116 . For example, when detecting a large decrease with respect to time in luminosity of a test window, OLED degradation manager  118  may derate the luminosity of test windows of OLED panel  116  to lower than the degraded luminosity still available in OLED panel  116 . Such dynamic derating may in some instances cause degradation to appear more linear to a user and/or may reduce a number of instances in which OLED degradation manager  118  may need to correct for non-linear degradation. 
     Although the foregoing contemplates correcting for degradation of OLED panel  116  based on a time-thermal and acceleration model, in some embodiments, OLED degradation manager  118  may correct for degradation of OLED panel  116  based on an application-level model which takes in account degradation of OLED panel  116  as a function of applications executing on information handling system  102 .  FIG. 3  illustrates a block diagram of selected components that may be used for degradation management of OLED panel  116 , including degradation management based on a time-thermal and acceleration model and an application-level model, in accordance with embodiments of the present disclosure. 
       FIG. 4  illustrates a flow chart of an example method  400  for management of degradation of OLED panel  116 , in accordance with embodiments of the present disclosure. According to some embodiments, method  400  may begin at step  402 . As noted above, teachings of the present disclosure may be implemented in a variety of configurations of information handling system  102 . As such, the preferred initialization point for method  400  and the order of the steps comprising method  400  may depend on the implementation chosen. 
     At step  402 , OLED degradation manager  118  may determine if conditions are present for initiating a calibration for OLED panel  116 . Such conditions may include one or more of passage of a period of time, whether components of information handling system  102  are drawing energy from AC source  107 , whether the workload of processor  103  is below a threshold, and/or which applications are executing on processor  103 . If conditions are present for initiating a calibration of OLED panel  116 , method  400  may proceed to step  404 . 
     At step  404 , OLED degradation manager  118  may logically divide OLED panel  116  into a plurality of non-overlapping test windows of defined size (e.g., 120 pixels by 120 pixels, 40 pixels by 40 pixels, etc.). In some instances, the sizes of the test windows may decrease over the lifespan of OLED panel  116 . 
     At step  406 , OLED degradation manager  118  may measure a physical quantity (e.g., pixel luminosity) for a pixel of each test window (e.g., bottom-right pixel, randomly-selected pixel, etc.), to determine the test window&#39;s deviation, if any, from a linear degradation profile. In some instances, OLED degradation manager  118  may measure such physical quantity for all test windows. In other instances, OLED degradation manager  118  may measure such physical quantity for each test window of a subset of the test windows identified to be at greater risk of degradation (e.g., test windows near a source of heat and/or test windows with frequently-used pixels). 
     At step  408 , OLED degradation manager  118  may correct for non-linear degradation occurring in any test window, as indicated by a test window&#39;s deviation, if any, from a linear degradation profile. For example, OLED degradation manager  118  may modify a frame buffer for display data to brighten or darken certain areas of an image to account for the non-linear degradation, or may control brightness of OLED panel  116  (e.g., via OLED controller  120 ), such that each test window of OLED panel  116  displays in accordance with its own brightness level. After completion of step  408 , method  400  may proceed again to step  402 . 
     Although  FIG. 4  discloses a particular number of steps to be taken with respect to method  400 , method  400  may be executed with greater or fewer steps than those depicted in  FIG. 4 . In addition, although  FIG. 4  discloses a certain order of steps to be taken with respect to method  400 , the steps comprising method  400  may be completed in any suitable order. 
     Method  400  may be implemented using information handling system  102 , and/or any other system operable to implement method  400 . In certain embodiments, method  400  may be implemented partially or fully in software and/or firmware embodied in computer-readable media. 
     As used herein, when two or more elements are referred to as “coupled” to one another, such term indicates that such two or more elements are in electronic communication or mechanical communication, as applicable, whether connected indirectly or directly, with or without intervening elements. 
     This disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Similarly, where appropriate, the appended claims encompass all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Moreover, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, or component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Accordingly, modifications, additions, or omissions may be made to the systems, apparatuses, and methods described herein without departing from the scope of the disclosure. For example, the components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses disclosed herein may be performed by more, fewer, or other components and the methods described may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order. As used in this document, “each” refers to each member of a set or each member of a subset of a set. 
     Although exemplary embodiments are illustrated in the figures and described below, the principles of the present disclosure may be implemented using any number of techniques, whether currently known or not. The present disclosure should in no way be limited to the exemplary implementations and techniques illustrated in the drawings and described above. 
     Unless otherwise specifically noted, articles depicted in the drawings are not necessarily drawn to scale. 
     All examples and conditional language recited herein are intended for pedagogical objects to aid the reader in understanding the disclosure and the concepts contributed by the inventor to furthering the art, and are construed as being without limitation to such specifically recited examples and conditions. Although embodiments of the present disclosure have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the disclosure. 
     Although specific advantages have been enumerated above, various embodiments may include some, none, or all of the enumerated advantages. Additionally, other technical advantages may become readily apparent to one of ordinary skill in the art after review of the foregoing figures and description. 
     To aid the Patent Office and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants wish to note that they do not intend any of the appended claims or claim elements to invoke 35 U.S.C. § 112(f) unless the words “means for” or “step for” are explicitly used in the particular claim.