Aging compensation for displays

Abstract

Disclosed is an aging compensation method and a computing device configured for aging compensation. Aging compensation can minimize or eliminate aging of an OLED display having regions with different pixel densities. Each region of the OLED display can be divided into multiple partitions including one or more pixels, and an aging factor can be calculated for these partitions. The extreme aging factor can be determined based on the extreme partition that exhibits the highest aging. Other partitions having aging factors significantly different from the extreme aging factor can be adjusted so that the pixels in the adjusted partitions can be driven to emit similar light at a power similar to that of the extreme partition. Aging compensation can be performed for each region, and transition regions can be created between regions to minimize light artifacts after aging compensation.

Description

Technical Field

[0001] The present disclosure relates to flat panel displays, and more particularly to an aging compensation method for an organic light emitting diode (OLED) display. Background Art

[0002] OLED displays include pixels that emit light when responding to an applied current. Each pixel may include an electroluminescent layer (e.g., an organic thin film) disposed between an anode and a cathode. One or both of the electrodes may be transparent to allow light generated by the electroluminescent layer to propagate through the (one or more) electrodes from the electroluminescent layer. The pixels of an OLED may be addressed using a thin film transistor (TFT) that may be controlled by a driver integrated circuit (i.e., a driver IC) so that each pixel receives (i.e., is driven) a current corresponding to an intensity specified by a pixel level. For example, the intensity may be a level selected from a possible range of pixel levels (e.g., 0-255). In order to represent a color image, a separate color channel (e.g., red, green, blue) may be specified for each pixel.

[0003] OLED displays may be more popular than other display technologies for a variety of reasons. For example, OLED displays can be made thinner and more efficient than other display technologies. Because each pixel of an OLED display emits light, an OLED display does not require a backlight and may not require a color filter such as that required by a liquid crystal display (LCD). The thin nature of an OLED display can contribute to flexibility (and in some cases transparency). For example, in some embodiments, an OLED display can be foldable. In addition, the light-emitting pixels of an OLED can result in higher contrast, high brightness, wider viewing angles, and faster refresh rates than other display technologies. But despite these advantages, OLED displays still have problems that can limit their use.

[0004] One problem with OLED displays is related to degradation of visible light intensity (i.e., brightness) with use. For example, the brightness of a pixel produced by the current specified by the pixel level can decrease with use. This can lead to a phenomenon (i.e., burn-in) in which more used pixels appear different (e.g., darker) than less used pixels. To compensate for aging, more used pixels can be driven differently than less used pixels. Embodiments of the present disclosure are conceived in this context. Summary of the invention

[0005] In at least one aspect, the present disclosure generally describes a technique for reducing the (harmful) effects of aging of an organic light emitting diode (i.e., OLED) display. For example, an aging factor of a sub-area in a region of the OLED display is estimated. A limit aging factor can be determined based on the (estimated) aging factor, and an aging factor that is significantly different from the (estimated) aging factor can be adjusted to update the aging factor of the sub-area in the region. A driver integrated circuit (i.e., driver IC) can then be controlled based on the updated aging factor to minimize the effects of aging in the region of the OLED display.

[0006] In a possible implementation, each partition can include one or more pixels, and each of the one or more pixels in the partition can be driven according to the updated aging factor of each partition.

[0007] In possible implementations, these techniques can be applied to other regions (eg, at least one other region) of the OLED display because the OLED display has multiple regions of different pixel densities.

[0008] In another possible implementation, these techniques can be applied over the lifetime of the display to minimize aging of the OLED display over time.

[0009] In at least one aspect, the present disclosure generally describes a method for reducing the effects of aging in an OLED display. The method includes: estimating aging factors for a plurality of sub-areas in a first region of the OLED display; determining a limit aging factor based on the estimated aging factors; adjusting the estimated aging factors that are significantly different from the limit aging factors; updating the aging factors for the plurality of sub-areas in the first region in a memory to include the adjusted aging factors; and controlling a driver IC based on the updated aging factors to reduce the effects of aging in the first region of the OLED display.

[0010] The aging factor of a partition may indicate the pixel efficiency of the partition. A relatively low aging factor of a region may correspond to a region with relatively low pixel efficiency. A relatively high aging factor of a region may correspond to a region with relatively high pixel efficiency.

[0011] The estimated aging factor that is significantly different from the limiting aging factor may be an estimated aging factor that satisfies a threshold, for example, is greater than the threshold. The threshold may be determined based on the limiting aging factor.

[0012] Controlling the driver IC according to the updated aging factor may include adjusting a drive signal for a pixel corresponding to the digital count of the pixel, the adjustment being based on the updated aging factor.

[0013] The method may further include: estimating aging factors of multiple partitions in a second area of ​​the OLED display, wherein the second area has a pixel density different from a pixel density of the first area of ​​the OLED display; determining a limit aging factor based on the estimated aging factors of the multiple partitions in the second area; adjusting the estimated aging factors of the multiple partitions in the second area that are significantly different from the limit aging factor of the second area; updating the aging factors of the multiple partitions in the second area in a memory to include the adjusted aging factor of the second area; and controlling a driver IC based on the updated aging factor to reduce the effects of aging in the second area of ​​the OLED display.

[0014] The method may further include repeating the estimating, the determining, the adjusting, the updating, and the controlling for the first region of the OLED display to minimize the effects of aging over time in the first region of the OLED display.

[0015] An OLED display may have high pixels per inch (high PPI) areas and low pixels per inch (low PPI) areas. For example, a high PPI area has a higher number of pixels per inch than a low PPI area.

[0016] The method may further include: specifying a transition region between the high PPI region and the low PPI region; and calculating an aging factor for the transition region, the aging factor gradually changing from the high PPI region to the low PPI region.

[0017] Each of the plurality of partitions may include one or more pixels. Each of the one or more pixels in the partition may be driven according to the updated aging factor of each partition.

[0018] Estimating aging factors for partitions in a region of an OLED display may include, for each partition: calculating a representative pixel level for the partition; determining a short-term usage for the partition; determining a cumulative usage for the partition; and correlating the cumulative usage with an estimate of the aging factor. The short-term usage for the partition may be determined based on the representative pixel level for the partition. The cumulative usage for the partition may be determined based on the short-term usage for the partition.

[0019] The short-term usage of a partition may be the average pixel level of the partition over the window period.

[0020] Cumulative usage can be a running total of short-term usage over time.

[0021] An estimate of the aging factor can be derived from a statistical analysis of a group of OLED displays similar to this OLED display.

[0022] Determining the limit aging factor according to the aging factor may include determining a minimum aging factor of the aging factors. For example, the limit aging factor may be an aging factor indicating a partition having the lowest pixel efficiency.

[0023] Adjusting an aging factor that is significantly different from a limit aging factor may include: determining an aging factor difference between an aging factor of a partition and a limit aging factor; comparing the aging factor difference to a threshold; and when the aging factor difference is above the threshold, adjusting the aging factor of the partition to match the limit aging factor; and repeating the determination, the comparison, and the adjustment for other partitions in the region.

[0024] The method may further include not adjusting the aging factor of the partition to match the limit aging factor when the aging factor is below the threshold.

[0025] In at least one aspect, the present disclosure generally describes a mobile computing device including an OLED display panel, a driver integrated circuit (IC), and an application processor configured by software instructions to implement the above method.

[0026] In at least one aspect, the present disclosure generally describes a mobile computing device. The mobile computing device includes an OLED display panel including a plurality of regions with different pixel densities, each region in the plurality of regions having a plurality of partitions, each of the plurality of partitions having a plurality of pixels; a driver integrated circuit (IC) configured to, for each of the plurality of partitions in each of the plurality of regions, convert a digital count into a drive signal, the drive signal causing the plurality of pixels of the partition to emit light at a level corresponding to the digital count; an application processor configured by software instructions to reduce the effects of aging in each of the plurality of regions of the OLED display by: estimating an aging factor for the plurality of partitions in the region of the OLED display; determining a limit aging factor based on the estimated aging factor; adjusting the estimated aging factor that is significantly different from the limit aging factor; updating the aging factor for the plurality of partitions in the region in a memory to include the adjusted aging factor; and controlling the driver IC to adjust the drive signal for the plurality of pixels in each of the partitions of the region based on the updated aging factor to reduce aging in the region of the OLED display.

[0027] The application processor can be further configured by the software instructions to minimize aging of each region of the OLED display by repeating the estimating, determining, adjusting, updating, and controlling for multiple regions of the OLED display to minimize aging of regions of the OLED display over time.

[0028] The application processor can be further configured by software instructions to estimate aging factors for multiple partitions in an area of ​​the OLED display by, for each partition, calculating a representative pixel level for the partition; determining a short-term usage of the partition; determining a cumulative usage of the partition; and correlating the cumulative usage with an estimate of the aging factor.

[0029] The application processor may be further configured by the software instructions to correlate the accumulated usage with an estimate of an aging factor by retrieving the estimate of the aging factor from a memory, the estimate of the aging factor derived from a statistical analysis of a group of OLED displays similar to the OLED display.

[0030] The application processor can be further configured by software instructions to adjust an estimated aging factor that is significantly different from a limit aging factor by the following steps: determining an aging factor difference between an aging factor of a partition and a limit aging factor; comparing the aging factor difference with a threshold; and when the aging factor difference is above the threshold, adjusting the aging factor of the partition to match the limit aging factor; and repeating the determination, the comparison, and the adjustment for other partitions in the region.

[0031] In another aspect, the present disclosure generally describes a mobile computing device that includes an OLED display panel having regions of different pixel densities and each region is subdivided into partitions of pixels. The mobile computing device further includes a driver IC configured to convert (for each partition) a digital count (i.e., a pixel level) into a drive signal that causes the pixels in the partition to emit light at a level corresponding to the digital count. The mobile computing device further includes an application processor configured by software instructions to reduce the effects of aging in each region of the OLED display by performing the following method, the method comprising: estimating an aging factor for a partition in a region of the OLED display; determining a limit aging factor based on the estimated aging factor; adjusting the estimated aging factor that is significantly different from the limit aging factor; updating the aging factor for the partition in the region; and controlling the driver IC to adjust the drive signal for the pixels in each partition of the region based on the corresponding updated aging factor to minimize the effects of aging in the region of the OLED display.

[0032] In another aspect, the present disclosure generally describes a non-transitory computer-readable storage medium (e.g., memory) containing program code, which, when executed by a processor (e.g., an application processor) of a computing device, causes the computing device to perform a method of reducing the effects of aging of an OLED display of the computing device. The method includes: estimating aging factors for partitions in a region of the OLED display; determining a limit aging factor based on the aging factors; adjusting aging factors that are significantly different from the limit aging factor; updating aging factors for partitions in the region; and controlling a driver IC based on the updated aging factors to minimize aging in the region of the OLED display.

[0033] Optional features of one aspect (such as a method) may be combined with any other aspect.

[0034] The above illustrative summary as well as other exemplary objects and / or advantages of the present disclosure and the manner of achieving the same are further explained in the following detailed description and its accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a front view of an OLED display showing residual images caused by aging.

[0036] Figure 2 is a front view of a mobile computing device having an OLED display having areas of varying pixel density.

[0037] Figure 3 is a system block diagram of a portion of a mobile computing device including an OLED display with aging compensation.

[0038] Figure 4 is a flow chart of an aging compensation method according to an embodiment of the present invention.

[0039] Figure 5 is a schematic diagram of an example OLED display divided into regions and zones according to an embodiment of the present disclosure.

[0040] Figure 6 It is estimated that Figure 4 Flow chart of the aging factors used in the method.

[0041] Figure 7 is the digital count for the partition (D C ) versus time.

[0042] Figure 8 is an example of an estimate of the aging factor and the accumulated years of use.

[0043] Fig. 9 is used to determine the applicable Figure 4Flowchart of the minimum aging factor of the method.

[0044] Fig.10 Is applicable to Figure 4 A flow chart of a method for updating aging factors for multiple partitions.

[0045] Fig.11 Graphically illustrates updating the aging factor for multiple partitions.

[0046] Fig.12 It is mathematically shown that it applies to Figure 4 A flow chart of a possible calculator of a method for updating an aging factor for multiple partitions.

[0047] Fig.13 A driver IC for an OLED display having a gain configured according to an updated aging factor according to possible implications of the present disclosure.

[0048] Fig.14 is a schematic diagram of an example OLED display divided into regions and zones according to an embodiment of the present disclosure.

[0049] Fig.15 Schematic diagram of the calculation of the aging factor of the transition area between the low pixel density area and the high pixel density area.

[0050] Fig.16 Examples of computer devices and mobile computer devices that can be used to implement the techniques described herein are shown.

[0051] The components in the drawings are not necessarily to scale relative to each other. In all the figures, the same reference numerals indicate corresponding parts. DETAILED DESCRIPTION

[0052] The present disclosure describes aging compensation for OLED displays having regions of different pixel densities (i.e., multiple resolution regions) in the same display. The disclosed aging compensation can manage the aging compensation of each resolution region based on its usage over time, and can minimize or eliminate boundary effects between resolution regions caused by their individual aging compensations. For example, visible defects (e.g., lines) between regions can be minimized or eliminated by the disclosed method. In this manner, the disclosed subject matter solves technical problems associated with aging effects on displays.

[0053] Burn-in can be a problem with OLED displays. Burn-in is due to uneven degradation of pixel efficiency and can manifest as a residual image (i.e., a shadow image) on the display (i.e., screen). Burn-in can be caused by pixel usage and / or a defective manufacturing process. Unlike burn-in on LCD displays, burn-in on OLED displays is irreversible and there is no compensation.

[0054] Figure 1 A mobile computing device 100 (e.g., a mobile phone, tablet computer, etc.) is illustrated having an OLED display 110 that includes pixels that exhibit aging. The pixels of the OLED display 110 shown are driven substantially at this level. Despite this uniform driving condition, a residual image 120 of a previously displayed user interface (UI) is still visible. The residual image caused by aging may appear to be a negative of a normally displayed image. For example, a bright pixel in a normally displayed image may be darker in the corresponding residual image. This relationship is caused because the efficiency of the OLED pixel decreases as it is used. Therefore, the OLED pixel may become darker over time.

[0055] The use of OLED pixels can correspond to the energy of the light generated by the OLED pixels (i.e., the power of the light generated by the pixel integrated over time). The power of the light generated by the OLED pixel at a particular time depends on the drive signal corresponding to the pixel level specified for the pixel. The specified higher pixel level configures the circuit to drive the pixel with a higher voltage and / or current in order to generate more light. Therefore, pixels driven (on average) with a higher pixel level are used more than pixels driven (on average) with a lower pixel level. Therefore, the display can have pixels of various efficiencies (i.e., aging levels). When pixels with different efficiencies (i.e., aging levels) are driven similarly, the pixels will transmit light with different powers (i.e., intensity, brightness). When the differences between the aging levels of pixels become significant (e.g., due to extended image display time), aging artifacts such as residual images may become visible.

[0056] To compensate for uneven pixel usage (i.e., pixel aging), more used pixels can be driven at a different current than less used pixels. For example, to have the same brightness, a first current can be used to drive more used pixels, while a second current can be used to drive less used pixels. For example, a more used (i.e., less efficient) pixel can be driven with a first current that is higher than a second current so as to increase the brightness of the more used pixel so that its brightness is the same as that of the less used (i.e., more efficient) pixel. In other words, aging compensation can be based on increasing (i.e., boosting) the driving point of the more used (i.e., darker) pixel. Alternatively, the less used pixel can be driven by a second current that is lower than the first current so as to reduce the brightness of the less used pixel so that its brightness is the same as that of the more used pixel. In other words, aging compensation can be based on reducing (i.e., compensating) the driving point of the less used (i.e., brighter) pixel. The present disclosure can be applied to either type of aging compensation, but aging compensation based on reducing brighter pixels (i.e., less aged pixels) to match darker pixels (i.e., more aged pixels) will be considered because this type can provide some advantages (e.g., power consumption) in certain embodiments.

[0057] OLED displays can be used in a variety of applications (e.g., televisions, mobile phones, tablet computers, etc.). The resolution of an OLED display is related to the number of pixels per inch (i.e., pixel density). In some applications (e.g., smartphones, tablet computers), it may be desirable for a single display panel (i.e., display) to have different pixel densities in different regions within the same display panel. In general, a display panel can have any number of different regions and any number of different pixel densities (i.e., pixel resolution, pixels per inch) corresponding to the different regions.

[0058] Figure 2 A multi-region OLED display according to an embodiment of the present disclosure is illustrated. As shown, a multi-region OLED display can occupy a large portion of the front surface of a mobile computing device 200 (e.g., a mobile phone). The OLED display of the mobile computing device 200 in the illustrated embodiment includes a high pixel per inch (i.e., high PPI) region 210 and a low pixel per inch (low PPI) region 220 (i.e., high relative to low and low relative to high). One possible motivation for such a display configuration can be based on one or more optical devices (e.g., light sensors, light sources) located behind the low PPI region 220 of the OLED display. The low PPI region 220 can allow enough light to propagate through the area where the optical device (or multiple optical devices) can function. Therefore, the operating display (although at a lower resolution) can be extended to the area that was once dedicated to one or more optical devices.

[0059] Pixels in regions of an OLED display with different pixel densities can be driven differently. For example, for a given pixel level, for a given pixel value, each pixel in a low PPI region 220 (i.e., a low pixel density region) can be driven brighter than each pixel in a high PPI region 210 (i.e., a high pixel density region). In other words, for a given pixel level, each pixel in a lower pixel density region 220 can be made brighter than a pixel in a higher pixel density region 210 to compensate for a smaller number of pixels. When such an adjustment is made, the brightness per unit area from a low PPI region 220 (i.e., a portion) of the display can be made equal to the brightness per unit area from a high PPI region 210 (i.e., a portion) of the display. In other words, these regions appear to have the same brightness.

[0060] The disclosed aging compensation techniques are described for an OLED display having two regions (eg, a high PPI region and a low PPI region), such as Figure 2 As shown. However, the present disclosure is not limited to this embodiment. The disclosed technology can be applied to OLED displays with additional areas of the same or different pixel density. In addition, the areas of different pixel density can be of any shape, any size, and any relative spatial configuration.

[0061] The disclosed aging compensation may be implemented as software, firmware, and / or hardware of a computing device (eg, a mobile computing device). Figure 33 is a system block diagram of a portion of a mobile computing device (e.g., a mobile phone, a tablet) configured with aging compensation. The mobile computing device 300 includes a graphics chip (i.e., a graphics accelerator) 310 and an application processor 330 to handle the processing necessary for controlling the driver IC 340 to configure the current provided to the pixels on the OLED display panel 350 (i.e., the OLED display) to generate a visible image. For example, a digital image (e.g., a JPEG image) can be stored in the memory 320 and can be processed (e.g., by the graphics accelerator and / or the application processor) to assign pixel values ​​from a possible pixel value range (e.g., 0-255) to corresponding pixels in the OLED display. The driver IC 340 is configured to convert the pixel value into the necessary signal to control the brightness of each pixel. For example, the driver IC can control one of a plurality of transistors corresponding to a pixel in a particular row and column of the OLED display panel 350 to provide a current to the pixel, wherein the level of the current is related to the pixel value. In other words, the driver IC 340 can act as an amplifier (e.g., a voltage-controlled current source) to provide a signal (e.g., a current) having an amplitude (e.g., a current level) corresponding to the pixel level to each pixel. For example, a higher pixel level corresponds to a larger amplitude signal at the corresponding output of the driver IC. In addition, as described below, the amplitude of the signal provided to each pixel can be further adjusted to compensate for aging corresponding to the pixel of the OLED display panel.

[0062] like Figure 3 As shown, an application processor (AP) can be configured to perform aging compensation 335. For example, the AP can be configured by software instructions retrieved from a non-volatile computer-readable memory (e.g., memory 320) to perform a method for aging compensation. When configured for aging compensation, the AP 330 can adjust a signal from the graphics chip 310 so as to control the driver IC to increase or decrease the signal amplitude for a given pixel level. Therefore, the disclosed aging compensation 335 can operate without affecting the operation of the graphics accelerator 310 or the driver IC 340. In other words, it is not necessary to adjust the display process or circuit in the mobile computing device 300 to implement the disclosed aging compensation.

[0063] Figure 4 4 is a flow chart of an aging compensation method according to an embodiment of the present invention. Method 400 can be performed on different regions of an OLED display having multiple regions. For example, method 400 can be performed for a first region having a first pixel density and for a second region having a second pixel density. The method performed for the first region can be performed in parallel or sequentially (i.e., performed) with the method performed for the second region.

[0064] Each region may be subdivided into partitions to simplify the computational requirements for the method. A partition can include one or more pixels. The size of each partition may be set so that a single pixel level and aging factor can represent all pixels within the partition, and so that the pixels in the partition may have similar physical and electrical properties due to their proximity. Furthermore, the pixels in the partition may have similar usage characteristics because the pixel density of the partition is typically much higher than the spatial frequency of the displayed image.

[0065] The method 400 can be performed periodically over the life of the OLED display so that the aging compensation can be modified as the OLED display is used. Each iteration of the method 400 can use short-term statistical information as well as accumulated information from previous iterations. Thus, the method 400 can store and retrieve the results of the iterations to and from the memory 320 of the mobile computing device.

[0066] The method may also store and retrieve OLED panel data to and from the memory 320 of the mobile computing device. The OLED panel data may include information about regions, partitions, and pixels of the OLED display. In addition to the region and partition designation, the OLED panel data may include statistical operational data associated with the OLED panel. The OLED panel data 401 may be obtained by statistical analysis (e.g., design of experiments) performed on a representative sample group of multiple OLED displays similar to the OLED display analyzed by the method 400. This step of obtaining 401 OLED panel data may occur at a different time (e.g., earlier) and a different location (e.g., a factory) than the other steps of performing the method 400. Therefore, the OLED panel data may be stored (e.g., factory settings) in the memory 320 of the mobile computing device. In a possible embodiment, the OLED panel data can be updated based on the results of the method 400.

[0067] The method for aging compensation includes calculating 410 an aging adjustment necessary to compensate for changes in light output from a partition in a region. The calculation 410 includes estimating 420 an aging factor for the partitions in the region (e.g., for each partition). In a possible embodiment, each partition is assigned an aging factor to represent the aging of all pixels in the partition. The aging factor corresponds to a representative pixel efficiency estimated for the partition based on the use of the partition. As a pixel (or pixels) in a partition is used, the efficiency pixel (or pixels) of the partition decreases. Therefore, in a possible embodiment, the aging factor of each partition decreases as the partition is used.

[0068] The calculation 410 of aging adjustment also includes determining 440 the limiting aging factors of the partitions in the region. In other words, the limiting partitions of the region can be determined. The limiting partition can be the partition with the most extreme aging factor (i.e., the limiting aging factor) among all the partitions in the region. Each partition can be used differently and therefore can have different luminescence for a specific pixel level. In order to adjust the pixels to have similar luminescence for a given pixel level, the output of the brighter pixels can be reduced to match the darker pixels. The limiting partition can have a limiting aging factor that is the minimum aging factor of all partitions. The minimum aging factor can correspond to the least efficient (i.e., the darkest partition for a specific pixel level) pixel and can serve as a baseline against which all other partitions can be compared and / or adjusted.

[0069] The calculation 410 of the aging adjustment can also include adjusting 460 the aging factor of the partitions having aging factors that are significantly different from the limiting aging factor. The adjustment 460 can include comparing the aging factor of the partition (e.g., each partition) with the limiting aging factor and determining the aging factor (partition) that is significantly different from the limiting aging factor (limiting partition). The adjustment can affect the drive signal of the pixels of the partition so that for a given pixel level, when the limiting partition is driven at the same pixel level, the partition outputs similar (e.g., the same) luminescence as the limiting partition. For example, if the brighter partition and its drive signal are calibrated (e.g., reduced) according to the limiting partition, then a (brighter) partition with an efficiency of 90% can be made to appear to have the same efficiency as a (darker) limiting partition with an efficiency of 30%.

[0070] The method 400 further includes outputting (480) the updated aging adjustment (i.e., the maintained or adjusted aging factor) to the driver IC. For example, one or more pixels in each partition can receive the same aging factor. The driver IC receives the aging factor and is configured with the aging factor to minimize the variation in pixels output for the same pixel level. In addition, the method can also output intermediate and / or final results of the aging adjustment calculation (410) to the memory 320. In this way, the aging factor can be updated as the OLED panel is used. Therefore, the method can include periodically performing aging compensation by repeating 490 the aging adjustment for the partition after a period of time.

[0071] In order to better understand the above method, Figure 5The example OLED display shown is an example, and an example implementation of the main steps of aging adjustment is described in detail. The example OLED display 500 is divided into a first area 510 (e.g., a high PPI area) and a second area 520 (e.g., a low PPI area). Each area is further subdivided into partitions (i.e., indicated by dotted lines). Each partition can contain one or more pixels. For example, a given partition 530 (i.e., the i-th partition) of the first area 510 includes a pixel 540 (i.e., five points indicating a pixel).

[0072] Each pixel in a partition may be driven at a different pixel level at any given time. Therefore, to calculate the aging factor for a partition, a representative pixel level for the partition may be derived. The representative pixel level may be any mathematical representation of the pixel levels. For example, the representative pixel level may correspond to the average (mean) of the pixel levels, the median pixel level, or any other statistically meaningful representation of the pixel levels. Furthermore, the representative pixel level for a partition may be referred to as a digital count (i.e., D ) of the partition. C ), because pixel levels typically correspond to a digital representation (e.g., indicated in an image file).

[0073] Figure 6 Including an estimated 420 Figure 4 Possible details of the step of estimating 420 the aging factor of the method shown. The step of estimating 420 comprises calculating 421 the digital count (D C ). For example, for Figure 5 For the i-th partition 530 shown in FIG. C ) can be the average of the five pixel levels of the partition at a given time (t).

[0074] The aging factor estimated (420) also includes the use of the digital count (D C ) determines (423) the short-term usage of each partition. The digital count (ie, pixel level) of each partition changes over time (ie, D C (t)). Figure 7 is an example plot of digital counts (ie, pixel levels) versus time for a partition. Short-term usage can be calculated as the short-term average of the digital counts for the partition (ie, E(D) over the window period). C (t)). In other words, it is possible to D The short-term average of the digit counts is calculated using the corresponding window, as shown in the following equation:

[0075]

[0076] For example, Figure 7 As shown, short-term use (e.g., at time t 1) can be in the window period 710 (ie, T D ) collected (i.e., sampled) on the five D C The average of the values.

[0077] like Figure 6 As shown, estimating 420 the aging factor also includes determining 425 the cumulative usage (ie, long-term usage) of each partition. The cumulative usage of a partition can be calculated as a running total of short-term usage over time, as shown in the following equation:

[0078]

[0079] For example, Figure 7 As shown, the accumulated usage can be at the first time (t 1 ), the second time (t 2 ) and the third time (t 3 ) is calculated in the window for short-term usage (i.e., average D C ). It can be used in the short-term use window period (T D ) cumulative usage can be calculated over a much longer duration. For example, cumulative usage can be calculated over the lifetime of an OLED panel. Thus, short-term usage can be calculated periodically, and the period 720 between short-term usage calculations can be selected based on a balance between calculation efficiency and the ability to capture efficiency drops that require aging compensation. Figure 7 As shown, the short-term usage samples may be periodic, wherein the period 720 between the short-term usage samples is longer than the short-term window period (T D )710.

[0080] like Figure 6 As shown, estimating 420 the aging factor also includes correlating 427 the accumulated usage with the aging factor (i.e., pixel efficiency) of each partition. As described above, the aging factor of a partition may be correlated with the pixel efficiency of the partition. For example, the aging factor of a given (i) partition in a high PPI region may have an aging factor f between zero (e.g., 0% efficiency) and 1 (e.g., 100% efficiency). H(i) Likewise, the aging factor for a given (i-th) region in the low PPI region may have an aging factor f between zero (eg, 0% efficiency) and 1 (eg, 100% efficiency). L(i) The aging factor (i.e., f H(i) , f L(i) ) may generally decrease with time. For example, as time extends to infinity (i.e., t→∞), the aging factor has a limit of zero.

[0081] The cumulative usage of a partition corresponds to time (i.e., increases over time). Therefore, the aging factor (i.e., f H(i) , f L(i)) decreases with increasing cumulative use. The details of how the aging factor decreases with cumulative use can be described by a function or curve. For example, the aging factor can decrease linearly with cumulative use, as shown in the following equation:

[0082]

[0083] Functions or curves can be determined theoretically or empirically. For example, Figure 4 As shown, determining a function or curve may be determined as part of the step of obtaining 401 OLED panel data. Figure 8 is an estimate of a possible aging factor versus cumulative usage. As shown, the estimate of the aging factor (e.g., for a partition) has a linear profile 820 that decreases with cumulative usage. The linear profile can be represented by a function having a slope (α) and an initial value (β). The parameters (α, β) of the function (i.e., estimate) can be derived based on a statistical analysis of a group of OLED displays similar to the OLED display. The results of the statistical analysis can be stored in a memory for use in estimating the aging factor based on the cumulative usage data. As Figure 8 As shown, the aging factor of a zone can be a value between 0 and 1, and can decrease (i.e., have a negative slope α) from an initial value (β=1) with usage until it reaches zero (i.e., until it extinguishes). The cumulative usage of each partition can be correlated (i.e., mapped) to an estimate of the aging factor (810), as shown in FIG. Figure 8 Correlation may also include (but is not limited to) curve fitting, extrapolation, interpolation, lookup or any similar operation to perform Figure 8 One or more parameters, values, or equations of the function or curve (i.e., estimation of aging versus usage) may be stored in memory and retrieved from memory 320 and may be part of the OLED panel data obtained 401 at an earlier time. The function or curve may be the same or different for each region of the display and may be any function, including but not limited to a linear function such as Figure 8 shown.

[0084] like Figure 6 As shown, the estimation 420 may be repeated (429) for each partition of each region. Thus, the step of estimating (420) the aging factor for the partitions may output a vector for the region (e.g., each region). The vector for the region (e.g., F H or F L ) includes an aging factor (ie, f) for a partition (eg, each partition) in the region H(i) , f L(i) ).

[0085] Fig. 9 Including for Figure 4The method shown in FIG. 4 shows details of the step of determining 440 a limiting aging factor for a region. The limiting aging factor corresponds to a partition of the region most affected by aging (i.e., a limiting partition). For example, the limiting partition may be a partition with the lowest efficiency light emission for a given digital count. Thus, the limiting aging factor may be a minimum aging factor. To determine the minimum aging factor for each region, the minimum aging factor may be analyzed (e.g., min(F H ), min(F L ))Aging factor vector (e.g., F H and F L ) to determine the minimum value (e.g., f Hmin , f Lmin ).

[0086] Fig.10 Includes adjustments (460) and Figure 4 Details of the steps for determining the aging factor of the method shown in the example are as follows: Figure 4 As shown, the processing step can receive 475 an aging factor vector (e.g., F H and F L ), and can also receive a limiting (eg, minimum) aging factor (eg, f) for region 477 Hmin , f Lmin )). Based on these inputs, the aging factor of the partition may be adjusted if the aging factor of the partition is significantly different from the limit aging factor, or the aging factor of the partition may be maintained if the aging factor of the partition is not significantly different from the limit aging factor. The output of adjustment 460 is the updated aging factor of the partition. The updated aging factor of the partition may include the adjusted aging factor (e.g., adjusted according to the previous iteration (time)), and may also include the maintained aging factor (i.e., not adjusted according to the previous iteration (time)). The updated aging factor can be represented as an undated aging factor vector 473 (e.g., F' H and F' L ).

[0087] like Fig.10 As shown, the aging factor of the partition can be updated 469 for each partition in each region. For a given partition in a region (e.g., f H(i) , f L(i) ), the updating 460 process includes determining 461 (eg, based on a comparison) an aging factor of the partition and an aging factor of a limit partition of the region (eg, f Hmin or Lmin). The significance of the aging factor difference is evaluated and a determination is made based on the significance 463. For example, the significance determination may include comparing the aging factor difference to a significance threshold (i.e., a threshold value). Further, if the aging factor difference exceeds the threshold value, then the aging factor difference may be determined to be significant. In one possible implementation, a difference between the aging factor of the partition and the aging factor of the limit partition that is greater than 10% of the limit aging factor can be considered significant. If the aging factor difference is significant, then the aging factor of the partition may be adjusted 465, and if the aging factor difference is not significant, then the aging factor of the partition may be maintained 467. Adjusting the aging factor may include reducing the aging factor of the partition by an amount based on the aging difference (e.g., f H(i) -f Hmin , f L(i) -f Lmin ). The process may be repeated 471 for other partitions (eg, each partition) in the region, and similarly, the process may be repeated for other regions (eg, each region).

[0088] Fig.11 Details of an example update of aging factors for partitions (e.g., 1, 2, 3, 4, ... N) in a region (e.g., a low PPI region (L)) are graphically illustrated. Prior to the update, the partitions had widely varying aging factors. The aging factors of a partition can correspond to the radiative efficiency of the partition. Thus, a larger aging factor can correspond to a high-efficiency partition compared to a smaller aging factor. In order to make the partitions appear to radiate with similar efficiency, the higher-efficiency regions can be calibrated to radiate with lower power. In other words, for a particular digital count, the optical power transmitted by the partition can be reduced to match the optical power transmitted by the extreme partition for the same particular digital count. Fig.11 The limit of the partition shown is the partition with the lowest aging factor (f Lmin ) partition (f L(2) ). The aging factor of a partition can be compared to the minimum aging factor to determine the aging factor difference (e.g., f L(1) –f Lmin ) is greater than the threshold (δ th ), as shown in the following equation:

[0089] |f L(i) -f Lmin |≥δ th_L

[0090] Out of Fig.11 For the purpose of the illustrated example, one region is shown, but generally all regions can be compared. In this case, each region can have the same threshold, or can have a different threshold.

[0091] like Fig.11 As shown, the aging factors fL(1), fL(3), and fL(N) can be considered to be significantly different from the aging factor fL(2) of the extreme partition. Therefore, the aging factors of these partitions can be adjusted by an amount (i.e., B L(1) , B L(3) , B L(N) ), so that the updated aging factor is closer to (e.g., matches) the aging factor of the limit partition. Mathematically, the adjustment can be expressed by the following equation:

[0092] f′ L(i) =f L(i) -E L(i)

[0093] B L(i) = k·(f L(i) -f Lmin )

[0094] 0≤k≤1

[0095] for Fig.11 In the example shown, the factor k is equal to 1. However, in general, a factor k less than 1 can be used. For example, a factor k less than 1 can be used to allow the aging factor to be adjusted iteratively to a limit aging factor. This method can be used to adapt to a changing aging factor. Fig.12 The results for high and low PPI regions are summarized mathematically in Figure 5 ) possible adjustment of the aging factor.

[0096] As described above, the method 400 for aging compensation outputs 480 an updated aging factor (ie, a maintained or adjusted aging factor) to the driver IC. Fig.13 1 shows a possible implementation of a driver IC. The driver IC may include multiple channels. For example, the driver IC may include a channel for each pixel in the display. Each channel can be configured to receive a digital count (D C ). For example, the digital count may correspond to an 8-bit digital representation of an illumination level in the range of 0 to 255. The driver IC may be further configured to convert the digital count into a signal for driving the pixel. For example, the driver IC may convert the digital count into a voltage (e.g., using a digital-to-analog converter), and may convert the voltage into a current for driving the pixel to emit light at a particular level (e.g., using a voltage-controlled current source).

[0097] In other words, the driver IC can be viewed as a multi-channel amplifier where the gain of each channel can be controlled by an updated aging factor. When each channel of the multi-channel amplifier controls a pixel, all amplifiers for the pixel in the partition can receive the same updated aging factor for control. The driver IC can have a portion of the channels corresponding to each region of the OLED display.

[0098] Aging compensation can be viewed as a calibration of the drive signal corresponding to the digital counts. Fig.13 As shown, the updated aging factor (f' H(i) , f' L(i) ) can be adjusted with the digital count of pixels (D CH(i) , D CH(i) )The corresponding pixel driving signal (Pixel H(i) ,Pixel L(i) ). For example, the updated aging factor can adjust the maximum current delivered to the pixel for the maximum digital count. In this case, the minimum drive signal can be kept at zero, while all other drive signals can be adjusted to span the digital count range equally.

[0099] Aging compensation can be derived and applied independently for each region. Figure 5 In the display shown, a first region (eg, a high PPI region) can have a first aging factor (f Hmin ), while the second region (e.g., the low PPI region) can have a second aging factor (f Lmin ) partitions. Such differences can (in some cases) result in intensity variations at the boundaries between regions (i.e., visible artifacts). Thus, in some embodiments, transition regions can be defined between regions where the aging factor of a region can be transitioned.

[0100] Fig.14 9 is a front view of an OLED display, including a low PPI region 910, a high PPI region 930, and a transition region 920 therebetween. The low PPI region, the high PPI region, and the transition region are each divided into partitions (i.e., designated by dashed lines). The i-th partition in the low PPI region can be designated as L(i) and can have a value designated as f L(i) The jth partition in the high PPI region can be designated as H(j) and has an aging factor designated as f H(j) The aging factor of the nth partition in the transition region can be designated as T(n). The aging factor of the transition region can be designated as f T(n), and can be calculated according to an equation including a weighting function (i.e., w(n)) to provide a smooth aging factor variation across the partition of the transition region between the low PPI region and the high PPI region, as shown in the following equation:

[0101] f T(n) =w(n)f H(j) +(1-w(n))f L(i)

[0102] against Fig.14 , Fig.15 The transition region partitions shown (i.e., T(1), T(2), T(3) between the low PPI partition (L(i)) and the high PPI partition (H(i))) can calculate three aging factors, illustrating an example aging calculation. As shown, as the partitions progress from the low PPI partition 910 to the high PPI partition 930 through the partitions in the transition region 920, the weighting function gradually changes (i.e., increases). Based on the above equation, the transition partition (i.e., T(3)) adjacent to the high PPI partition (H(j)) can have the same aging factor as the high PPI partition (i.e., f T(3) =f H(j) Likewise, the transition partition (ie, T(1)) adjacent to the low PPI partition (L(i)) can have the same aging factor (ie, f T(1) =f L(i) ). Partitions between adjacent partitions can have aging factors between these aging factors (f T(2) ). For example, the partition could be the average of the other partitions. Fig.15 The examples shown are non-limiting.In general, the transition region 920 can include any number of partitions between the first region and the second region.

[0103] The transition region 920 may be designated as part of a high PPI region or may be designated as part of a low PPI region. In other words, the transition region may have a pixel density (ie, pixel resolution) that matches the high PPI region or the low PPI region.

[0104] Fig.16Examples of a general purpose computer device 1600 and a general purpose mobile computer device 1650 are shown that can be used with the techniques described herein. Computing device 1600 is intended to represent various forms of digital computers, such as laptops, desktops, tablet computers, workstations, personal digital assistants, televisions, servers, blade servers, mainframes, and other appropriate computing devices. Computing device 1650 is intended to represent various forms of mobile devices, such as personal digital assistants, cellular phones, smart phones, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are intended to be exemplary only and are not intended to limit the embodiments of the inventions described and / or claimed in this document.

[0105] The computing device 1600 includes a processor 1602, a memory 1604, a storage device 1606, a high-speed interface 1608 connected to the memory 1604 and a high-speed expansion port 1610, and a low-speed interface 1612 connected to a low-speed bus 1614 and the storage device 1606. The processor 1602 can be a semiconductor-based processor. The memory 1604 can be a semiconductor-based memory. Each component 1602, 1604, 1606, 1608, 1610, and 1612 are interconnected using various buses and can be installed on a common motherboard or installed in other ways as appropriate. The processor 1602 can process instructions 1600 for execution within the computing device 1600, including instructions stored on the memory 1604 or the storage device 1606, for displaying graphical information for a GUI on an external input / output device, such as a display 1616 coupled to the high-speed interface 1608. In other embodiments, multiple processors and / or multiple buses can be used together with multiple memories and multiple types of memories as appropriate. Furthermore, multiple computing devices 1600 may be connected, with each device providing a portion of the necessary operations (eg, as a server bank, a group of blade servers, or a multi-processor system).

[0106] Memory 1604 stores information within computing device 1600. In one implementation, memory 1604 is a volatile memory unit or units. In another implementation, memory 1604 is a non-volatile memory unit or units. Memory 1604 may also be another form of computer-readable medium, such as a magnetic disk or optical disk.

[0107] Storage device 1606 can provide mass storage for computing device 1600. In one embodiment, storage device 1606 can be or include a computer readable medium, such as a floppy disk device, a hard disk device, an optical disk device, or a magnetic tape device, a flash memory or other similar solid-state memory device, or an array of devices, including devices in a storage area network or other configuration. A computer program product can be tangibly embodied in an information carrier. The computer program product can also include instructions that, when executed, perform one or more methods, such as those described above. The information carrier is a computer or machine readable medium, such as memory 1604, storage device 1606, or memory on processor 1602.

[0108] The high-speed controller 1608 manages bandwidth-intensive operations of the computing device 1600, while the low-speed controller 1612 manages less bandwidth-intensive operations. This allocation of functions is exemplary only. In one embodiment, the high-speed controller 1608 is coupled to the memory 1604, the display 1616 (e.g., through a graphics processor or accelerator), and to the high-speed expansion port 1610, which can receive various expansion cards (not shown). In this embodiment, the low-speed controller 1612 is coupled to the storage device 1606 and the low-speed expansion port 1614. The low-speed expansion port, which can include various communication ports (e.g., USB, Bluetooth, Ethernet, wireless Ethernet), can be coupled to one or more input / output devices, such as a keyboard, a pointing device, a scanner, or a network device such as a switch or router, for example, through a network adapter.

[0109] The computing device 1600 can be implemented in a variety of different forms, as shown in the figures. For example, it can be implemented as a standard server 1620, or multiple times in such a server group. It can also be implemented as part of a rack server system 1624. In addition, it can be implemented in a personal computer such as a laptop computer 1622. Alternatively, components from the computing device 1600 can be combined with other components (not shown) in a mobile device such as device 1650. Each of these devices can contain one or more of the computing devices 1600, 1650, and the entire system can be composed of multiple computing devices 1600, 1650 that communicate with each other.

[0110] Computing device 1650 includes, among other components, a processor 1652, a memory 1664, an input / output device such as a display 1654, a communication interface 1666, and a transceiver 1668. Device 1650 may also be provided with a storage device such as a microdrive or other device to provide additional storage. Each of components 1650, 1652, 1664, 1654, 1666, and 1668 are interconnected using various buses, and several components may be mounted on a common motherboard or otherwise as appropriate.

[0111] Processor 1652 is capable of executing instructions within computing device 1650, including instructions stored in memory 1664. The processor may be implemented as a chipset of chips that includes separate multiple analog and digital processors. For example, the processor may provide coordination of other components of device 1650, such as control of a user interface, applications running on device 1650, and wireless communications through device 1650.

[0112] The processor 1652 can communicate with the user through the control interface 1658 and the display interface 1656 coupled to the display 1654. The display 1654, for example, can be a TFT LCD (thin film transistor liquid crystal display) or an OLED (organic light emitting diode) display, or other appropriate display technology. The display interface 1656 may include appropriate circuits for driving the display 1654 to present graphics and other information to the user. The control interface 1658 can receive commands from the user and convert them for submission to the processor 1652. In addition, an external interface 1662 that communicates with the processor 1652 can be provided to enable near-area communication of the device 1650 with other devices. The external interface 1662, for example, can provide wired communication in some embodiments, or wireless communication in other embodiments, and multiple interfaces can also be used.

[0113] Memory 1664 stores information within computing device 1650. Memory 1664 can be implemented as one or more of a computer-readable medium or medium, a volatile memory unit, or a non-volatile memory unit. An expansion memory 1674 may also be provided and connected to device 1650 via an expansion interface 1672, which may include, for example, a SIMM (single in-line memory module) card interface. Such expansion memory 1674 may provide additional storage space for device 1650, or may also store applications or other information of device 1650. Specifically, expansion memory 1674 may include instructions to implement or supplement the above-mentioned processing, and may also include security information. Thus, for example, expansion memory 1674 may be provided as a security module for device 1650, and may be programmed with instructions that permit secure use of device 1650. In addition, a security application may be provided via a SIMM card together with additional information, such as placing identification information on a SIMM card in a non-invasive manner.

[0114] The memory may include, for example, flash memory and / or NVRAM memory, as described below. In one embodiment, a computer program product is tangibly embodied in an information carrier. The computer program product includes instructions that, when executed, perform one or more methods, such as those described above. The information carrier is a computer or machine readable medium, such as memory 1664, expansion memory 1674, or memory on processor 1652, which may be received, for example, via transceiver 1668 or external interface 1662.

[0115] Device 1650 can communicate wirelessly via communication interface 1666, which can include digital signal processing circuitry as necessary. Communication interface 1666 can provide communication under various modes or protocols, such as GSM voice calls, SMS, EMS or MMS messages, CDMA, TDMA, PDC, WCDMA, CDMA2000 or GPRS, etc. Such communication can occur, for example, via radio frequency transceiver 1668. In addition, short-range communication can occur, such as using Bluetooth, WiFi or other such transceivers (not shown). In addition, GPS (global positioning system) receiver module 1670 can provide additional navigation and location-related wireless data to device 1650, which can be used as appropriate by applications running on device 1650.

[0116] Device 1650 may also communicate audibly using audio codec 1660, which may receive voice information from a user and convert it into usable digital information. Audio codec 1660 may likewise generate audible sounds for the user, such as through a speaker, e.g., in an earpiece of device 1650. Such sounds may include sounds from voice phone calls, may include recorded sounds (e.g., voice messages, music files, etc.), and may also include sounds generated by applications operating on device 1650.

[0117] The computing device 1650 can be implemented in many different forms, as shown in the drawings. For example, it can be implemented as a cellular phone 1680. It can also be implemented as part of a smart phone 1682, a personal digital assistant, or other similar mobile devices.

[0118] Various implementations of the systems and techniques described herein can be implemented in digital electronic circuitry, integrated circuitry, specially designed ASICs (application specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementations in one or more computer programs executable and / or interpretable on a programmable system, the programmable system comprising at least one programmable processor, which can be special purpose or general purpose, coupled to receive data and instructions from and transmit data and instructions to a storage system, at least one input device, and at least one output device.

[0119] These computer programs (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and may be implemented in high-level procedural and / or object-oriented programming languages ​​and / or in assembly / machine language. As used herein, the terms "machine-readable medium," "computer-readable medium" refer to any computer program product, device, and / or device (e.g., disk, optical disk, memory, programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including a machine-readable medium that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal for providing machine instructions and / or data to a programmable processor.

[0120] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user, and a keyboard and pointing device (e.g., a mouse or trackball) from which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, voice, or tactile input.

[0121] The systems and techniques described herein can be implemented in a computing system that includes a back-end component (e.g., as a data server) or includes a middleware component (e.g., an application server) or includes a front-end component (e.g., a client computer with a graphical user interface or a web browser through which a user can interact with an implementation of the systems and techniques described herein), or any combination of these back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), and the Internet.

[0122] A computing system can include clients and servers. Clients and servers are generally remote from each other and usually interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.

[0123] A number of embodiments have been described, but it will be appreciated that various modifications can be made without departing from the spirit and scope of the invention.

[0124] In addition, the logic flows shown in the accompanying drawings do not require the specific order or sequential order shown to achieve the desired results. In addition, other steps can be provided, or steps can be eliminated from the described processes, and other components can be added to the system, or other components can be removed from the system. Therefore, other embodiments are within the scope of the following claims.

[0125] The use of the term "and / or" includes any and all combinations of one or more of the associated listed items. The accompanying drawings are schematic representations and are not necessarily drawn to scale. Unless otherwise indicated, specific terms are used in a generic and descriptive sense and not for purposes of limitation.

[0126] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art. Methods and materials similar or equivalent to the methods and materials described herein can be used in the practice or testing of the present disclosure. As used in the specification and the appended claims, the singular forms "a", "an", "the" include plural indications unless the context clearly dictates otherwise. As used herein, the term "includes" and its variants are used synonymously with the term "includes" and its variants, and are open, non-restrictive terms. The term "optional" or "optionally" used herein means that the features, events or situations described subsequently may or may not occur, and the description includes situations where the features, events or situations occur and situations where they do not occur. In this article, the range can be expressed as from "about" a specific value, and / or to "about" another specific value. When expressing such a range, the aspect includes from a specific value and / or to another specific value. Similarly, when a value is expressed as an approximation, by using the antecedent "about", it will be understood that the specific value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant relative to the other endpoints, and independent of the other endpoints.

[0127] Although certain features of the embodiments have been described as described herein, many modifications, substitutions, changes and equivalents will be expected by those skilled in the art. It should therefore be understood that the appended claims are intended to cover all such modifications and changes that fall within the scope of the embodiments. It should be understood that they are presented by way of example and not limitation, and that various changes in form and detail may be made. Any part of the apparatus and / or method described herein may be combined in any combination, except mutually exclusive combinations. The embodiments described herein can include various combinations and / or sub-combinations of the functions, components and / or features of different embodiments.

Claims

1. A method for reducing the effects of aging of an OLED display, the method comprising: estimating aging factors for a plurality of subareas in a first region of the OLED display, wherein the aging factor of a region corresponds to a pixel efficiency of the region; Determining a limit aging factor according to the aging factor; adjusting the aging factor that is significantly different from the limiting aging factor; updating, in a memory, the aging factors of the plurality of partitions in the first region to include the adjusted aging factors; controlling a driver IC according to the updated aging factor to reduce the effects of aging in the first region of the OLED display; estimating aging factors for a plurality of subareas in a second region of the OLED display, wherein the second region has a pixel density different from a pixel density of the first region of the OLED display; determining a limit aging factor based on the aging factors of the plurality of subareas in the second area; adjusting the aging factors of the plurality of subareas in the second region that are significantly different from a limiting aging factor of the second region; updating, in memory, the aging factors of the plurality of partitions in the second region to include the adjusted aging factor of the second region; and A driver IC is controlled according to the updated aging factor to reduce the effects of the aging in the second area of ​​the OLED display.

2. The method according to claim 1, further comprising: The operations of estimating, determining, adjusting, updating, and controlling are repeated for the first region of the OLED display to minimize effects of aging over time in the first region of the OLED display.

3. The method according to claim 1, wherein: The OLED display has high pixels per inch (high PPI) areas and low pixels per inch (low PPI) areas.

4. The method according to claim 3, further comprising: specifying a transition region between the high PPI region and the low PPI region; as well as An aging factor of the transition region gradually changing from the high PPI region to the low PPI region is calculated.

5. The method according to claim 1, wherein: Each of the plurality of partitions includes one or more pixels; and Each pixel of the one or more pixels in each partition is driven according to the updated aging factor for the partition.

6. The method according to claim 1, wherein: Estimating aging factors for sub-regions in a region of the OLED display includes, for each sub-region: calculating a representative pixel level of the partition; determining a short-term use of the partition; determining a cumulative usage of the partition; as well as The accumulated usage is correlated to an estimate of the aging factor.

7. The method according to claim 6, wherein: The short term usage of the partition is the average pixel level of the partition over the window period.

8. The method according to claim 6, wherein: The cumulative usage is a running total of the short-term usage over time.

9. The method according to claim 1, wherein: The estimating of the aging factor includes obtaining OLED panel data derived from a statistical analysis of a group of OLED displays similar to the OLED display.

10. The method according to claim 1, wherein: Determining the limit aging factor according to the aging factor includes: A minimum aging factor of the aging factors is determined.

11. The method according to any one of claims 1 to 10, wherein: Adjusting aging factors that differ significantly from the limiting aging factors includes: determining an aging factor difference between an aging factor of a partition and the limit aging factor; comparing the aging factor difference to a threshold value; and When the aging factor difference is above the threshold, adjusting the aging factor of the partition to match the limit aging factor; and The operations of determining, comparing and adjusting are repeated for other partitions in the region.

12. The method according to claim 11, further comprising: When the aging factor is below the threshold, the aging factor of the partition is not adjusted to match the limit aging factor.

13. A mobile computing device comprising: An OLED display panel, the OLED display panel comprising a plurality of regions with different pixel densities, each of the plurality of regions having a plurality of partitions, each of the plurality of partitions having a plurality of pixels; a driver integrated circuit IC configured to convert the digital count into a drive signal for each of the plurality of partitions in each of the plurality of regions, the drive signal causing the plurality of pixels of the partition to emit light at a level corresponding to the digital count; An application processor configured by software instructions to reduce the effects of aging in each of the plurality of regions of the OLED display by performing the method according to any one of claims 1-12.

14. A non-transitory computer-readable storage medium containing program code, which, when executed by a processor of a computing device, causes the computing device to perform the method according to any one of claims 1-12.

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