The disclosure relates to a display device, and in particular, to a processor and a pixel degradation compensation method thereof.
For organic light-emitting diode (OLED) displays, pixel degradation (or burn-in) is one of the many technical issues. Different operating temperatures, OLED materials, and driving currents may cause sub-pixels to suffer different degradation effects. A lookup table (LUT) established based on optical measurements for accumulation of decay factor (DF) and data compensation may overcome such a problem. In the case where the brightness of the sub-pixel is attenuated due to degradation, the brightness attenuation may be improved by appropriately increasing/compensating the digital value (grayscale value) of the sub-pixel data. For the degraded sub-pixels, the more severe the brightness attenuation, the greater the compensation value of the sub-pixel data (the additional compensation current applied to the degraded sub-pixels), so as to maintain the degraded sub-pixels at the target brightness. However, the upscaling space (compensation region) of sub-pixel data is limited.
However, the degradation speeds of red sub-pixels, green sub-pixels, and blue sub-pixels are different.
It should be noted that the content of the paragraph of “description of related art” is used to help understand the disclosure. Some (or all) of the content disclosed in the paragraph of “description of related art” may not be known to those with ordinary skill in the art. The content disclosed in the paragraph of “description of related art” does not mean that the content has been known to those with ordinary skill in the art prior to the application of the present application.
The disclosure provides a processor and a pixel degradation compensation method thereof to compensate sub-pixel degradation.
In an embodiment of the disclosure, the above-mentioned processor includes a processing circuit and a pixel degradation compensation circuit. The pixel degradation compensation circuit is coupled to the processing circuit to receive a sub-pixel data stream. The pixel degradation compensation circuit is configured to compensate the sub-pixel data stream so as to generate a compensated sub-pixel data stream to the display module. The pixel degradation compensation circuit generates a current degradation value corresponding to current sub-pixel data based on the current sub-pixel data in the sub-pixel data stream. The current degradation value represents the degradation effect of the current sub-pixel data on a sub-pixel corresponding to the current sub-pixel data in the display module. The pixel degradation compensation circuit selectively adjusts the current degradation value to generate an adjusted degradation value. The pixel degradation compensation circuit accumulates the adjusted degradation value to the total degradation value corresponding to the current sub-pixel data. The pixel degradation compensation circuit compensates the current sub-pixel data based on the total degradation value corresponding to the current sub-pixel data so as to generate compensated current sub-pixel data in the compensated sub-pixel data stream to the display module.
In an embodiment of the disclosure, the above pixel degradation compensation method includes the following steps. A current degradation value corresponding to current sub-pixel data is generated based on the current sub-pixel data in a sub-pixel data stream. The current degradation value represents the degradation effect of the current sub-pixel data on a sub-pixel corresponding to the current sub-pixel data in a display module. The current degradation value is selectively adjusted to generate an adjusted degradation value. The adjusted degradation value is accumulated to a total degradation value corresponding to the current sub-pixel data. The current sub-pixel data is compensated based on the total degradation value corresponding to the current sub-pixel data so as to generate compensated current sub-pixel data in a compensated sub-pixel data stream to the display module.
Based on the above, the pixel degradation compensation circuit according to the embodiment of the disclosure may compensate the sub-pixel data stream of the processing circuit to generate the compensated sub-pixel data stream to the display module. In an embodiment, the pixel degradation compensation circuit may apply “dynamic decay factor accumulate speed” to compensate the sub-pixel degradation of the display module so as to overcome the technical issue of color shift. In detail, after the pixel degradation compensation circuit generates the current degradation value based on the current sub-pixel data, the pixel degradation compensation circuit may determine whether to adjust the current degradation value to be added to the total degradation value based on a margin of the compensation value in the compensation region (and/or based on a margin of the total degradation value in the total degradation value range) so as to slow down the accumulation speed of the degradation value before the compensation region is saturated (and/or before the total degradation value range is saturated). Based on this, the pixel degradation compensation circuit may slow down the saturation time of the compensation region (and/or the total degradation value range) to avoid the occurrence of color shift. In addition, the pixel degradation compensation circuit may slow down the accumulation speed of the total degradation value (reduce the additional compensation current for the sub-pixel) according to the situation to prolong the life of the sub-pixel.
In order to make the above-mentioned features and advantages of the disclosure clearer and easier to understand, the following embodiments are given and described in details the accompanying drawings as follows.
The term “coupled (or connected)” used throughout the specification (including the claims) may refer to any direct or indirect means of connection. For example, if a first device is described as being coupled (or connected) to a second device, it should be interpreted that the first device may be directly connected to the second device, or the first device may be indirectly connected to the second device through other devices or some connection means. Terms such as “first” and “second” used throughout the specification (including the claims) are used to name elements, or to distinguish different embodiments or ranges, rather than to restrict the upper limit or the lower limit of the number of elements, nor are they intended to restrict the order of the elements. In addition, wherever possible, elements/components/steps using the same reference numerals in the drawings and embodiments represent the same or similar parts. Elements/components/steps that have the same reference numerals or names in different embodiments may serve as reference for each other.
In the embodiment shown in
In terms of hardware, the processor 200, the processing circuit 210, and (or) the pixel degradation compensation circuit 220 may be implemented as a logic circuit on an integrated circuit. For example, the relevant functions of the processor 200, the processing circuit 210, and (or) the pixel degradation compensation circuit 220 may be implemented in one or more controllers, a microcontroller, a microprocessor, an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a field programmable gate array (FPGA), a central processing unit (CPU), and/or various logic blocks, modules, and circuits in other processing units. The relevant functions of the processor 200, the processing circuit 210, and (or) the pixel degradation compensation circuit 220 may be implemented as hardware circuits by using hardware description languages (such as Verilog HDL or VHDL) or other suitable programming languages, such as various logic blocks, modules, and circuits in integrated circuits.
In terms of software and/or firmware, the related functions of the processor 200, the processing circuit 210, and (or) the pixel degradation compensation circuit 220 may be implemented as programming codes. For example, the processor 200, the processing circuit 210, and (or) the pixel degradation compensation circuit 220 are implemented by using general programming languages (such as C, C++, or combination language) or other suitable programming languages. The programming code may be recorded/stored in a “non-transitory machine-readable storage medium”. In some embodiments, the non-transitory machine-readable storage medium includes, for example, a semiconductor memory and/or a storage device. An electronic device (such as a computer, a CPU, a controller, a processor, a microcontroller, or a microprocessor) may read and execute the programming code from the non-transitory machine-readable storage medium, thereby implementing the related functions of the processor 200, the processing circuit 210, and (or) the pixel degradation compensation circuit 220.
The pixel degradation compensation circuit 220 is coupled to the processing circuit 210 to receive a sub-pixel data stream D2. The pixel degradation compensation circuit 220 may compensate the sub-pixel data stream D2 to generate a compensated sub-pixel data stream D3 to the display module 10. The pixel degradation compensation circuit 220 may apply the technology of “dynamic decay factor accumulate speed” to compensate the sub-pixel degradation of the display module 10 so as to overcome the technical issue of color shift. A specific example of the technology of “dynamic decay factor accumulate speed” may be described below.
The driving value range (total grayscale range) of the display module 10 may be divided into an image region and a compensation region. For example, assuming that the driving value range of the display module 10 is 0 to N, the grayscale range 0 to n may be defined as the image region, and the grayscale range n+1 to N may be defined as the compensation region, where n and N are integers determined according to actual design, and 0<n<N. In step S320, the pixel degradation compensation circuit 220 may selectively adjust the current degradation value to generate an adjusted degradation value. The operation may be dynamically performed. For example (but not limited thereto), in the case that the compensation region has a sufficient margin (and/or a total degradation value range has a sufficient margin), the pixel degradation compensation circuit 220 may decide not to adjust the current degradation value. That is, the current degradation value is directly used as the adjusted degradation value. In the case where the margin of the compensation region is small (and/or the margin of the total degradation value range is small), the pixel degradation compensation circuit 220 may generate the adjusted degradation value that is less than the current degradation value.
In step S330, the pixel degradation compensation circuit 220 may accumulate the adjusted degradation value to the total degradation value corresponding to the current sub-pixel data. The pixel degradation compensation circuit 220 may save the total degradation value corresponding to each sub-pixel of the display module 10. For example, assuming that the display module 10 has x*y pixels and each pixel has three sub-pixels of different colors, the pixel degradation compensation circuit 220 may store x*y*3 total degradation values in a total degradation value lookup table (LUT). Each total degradation value represents the current degradation degree of a certain corresponding sub-pixel.
In step S340, based on the total degradation value corresponding to the current sub-pixel data, the pixel degradation compensation circuit 220 may compensate the current sub-pixel data to generate compensated current sub-pixel data in the compensated sub-pixel data stream D3 to the display module 10. For example, a compensation value lookup table prepared in advance based on the actual design may be configured in the pixel degradation compensation circuit 220. The pixel degradation compensation circuit 220 may search the compensation value lookup table based on the total degradation value corresponding to the current sub-pixel data so as to obtain a compensation value corresponding to the total degradation value. The pixel degradation compensation circuit 220 may use the compensation value to compensate the current sub-pixel data so as to generate the compensated current sub-pixel data. Therefore, when the brightness of the sub-pixel is attenuated due to degradation, the degraded sub-pixel may be maintained at the target brightness by appropriately increasing/compensating the digital value (grayscale value) of the sub-pixel data.
To sum up, the pixel degradation compensation circuit 220 of the embodiment may compensate the sub-pixel data stream D2 of the processing circuit 210 to generate the compensated sub-pixel data stream D3 to the display module 10. After the pixel degradation compensation circuit 220 generates the current degradation value based on the current sub-pixel data, the pixel degradation compensation circuit 220 may determine whether to adjust the current degradation value to be added to the total degradation value based on the margin of the compensation value in the compensation region (and/or the margin of the total degradation value in the total degradation value range) so as to slow down the accumulation speed of the degradation value before the compensation region is saturated (and/or before the total degradation value range is saturated). Therefore, the pixel degradation compensation circuit 220 may apply the technology of “dynamic attenuation factor accumulation speed” to compensate the sub-pixel degradation of the display module. Based on this, the pixel degradation compensation circuit 220 may slow down the saturation time of the compensation region (and/or the total degradation value range) to avoid the occurrence of color shift. In addition, the pixel degradation compensation circuit 220 may slow down the accumulation speed of the total degradation value (reduce the increase in the additional compensation current for the sub-pixel) according to the situation to prolong the life of the sub-pixel.
Please refer to
The multiplication circuit 222 is coupled to the degradation value generation circuit 221 to receive the current degradation value DF41. The multiplication circuit 222 may adjust the current degradation value DF41 based on an accumulation speed weight W to generate an adjusted degradation value DF42 corresponding to the current sub-pixel data. For example (but not limited thereto), when the total degradation value range has a sufficient margin, the accumulation speed weight W is “1”, so the multiplication circuit 222 directly uses the current degradation value DF41 as the adjusted degradation value DF42. When there is little margin in the total degradation value range, the accumulation speed weight W is less than 1, so the multiplication circuit 222 may generate an adjusted degradation value DF42 that is less than the current degradation value DF41.
The degradation value accumulation circuit 223 is coupled to the multiplication circuit 222 to receive the adjusted degradation value DF42. The degradation value accumulation circuit 223 may accumulate the adjusted degradation value DF42 corresponding to the current sub-pixel data to a total degradation value TDF4 corresponding to the current sub-pixel data. The degradation value accumulation circuit 223 may save the total degradation value TDF4 corresponding to each sub-pixel of the display module 10. For example, assuming that the display module 10 has x*y pixels and each pixel has three sub-pixels of different colors, the degradation value accumulation circuit 223 may store x*y*3 total degradation values in the total degradation value lookup table. Each total degradation value represents the current degradation degree of a certain corresponding sub-pixel.
The accumulation speed adjustment circuit 224 is coupled to the degradation value accumulation circuit 223 to receive the total degradation value TDF4. In any case, the total degradation value range of the total degradation value TDF4 is limited. For example, the memory used to store the total degradation value lookup table is limited, so the limited value range of the total degradation value TDF4 may be saturated. For another example, the number of bits of the total degradation value TDF4 is limited, so the limited value range of the total degradation value TDF4 may be saturated. In step S530, the accumulation speed adjustment circuit 224 of the pixel degradation compensation circuit 220 may check the margin in the total degradation value range of the total degradation value TDF4 corresponding to each sub-pixel data in an image frame of the sub-pixel data stream D2 so as to obtain the check result. In step S540, the accumulation speed adjustment circuit 224 may adjust the accumulation speed weight W corresponding to the current sub-pixel data based on the check result of the total degradation value TDF4.
In an embodiment, the accumulation speed adjustment circuit 224 may adjust the accumulation speed weight W to be the first weight value, in response to the check result indicating that the margin of the total degradation value TDF4 in the total degradation value range corresponding to any sub-pixel data in the image frame is greater than the first threshold value. The first threshold value may be determined according to actual design. The accumulation speed adjustment circuit 224 may adjust the accumulation speed weight W to the second weight value less than the first weight value, in response to the check result indicating that the margin of the total degradation value TDF4 in the total degradation value range corresponding to any sub-pixel data in the image frame is less than the first threshold value. The first weight value the second weight value may be determined according to actual design. For example, the first weight value is 1, and the second weight value is a positive number less than 1.
In another embodiment, the accumulation speed adjustment circuit 224 may adjust the accumulation speed weight W to be the second weight value, in response to the check result indicating that the margin of the total degradation value TDF4 in the total degradation value range corresponding to any sub-pixel data in the image frame is less than the first threshold value and greater than the second threshold value. The first threshold value and the second threshold value may be determined according to actual design. The first threshold value is greater than the second threshold value. The accumulation speed adjustment circuit 224 may adjust the accumulation speed weight W to be the third weight value less than the second weight value, in response to the check result indicating that the margin of the total degradation value TDF4 in the total degradation value range corresponding to any sub-pixel data in the image frame is less than the second threshold value. The second weight value and the third weight value may be determined according to actual design.
For example,
Please refer to
The compensation value circuit 225 is coupled to the degradation value accumulation circuit 223 to receive the total degradation value TDF4. In step S560, the compensation value circuit 225 generates a compensation value CV4 corresponding to the current sub-pixel data based on the total degradation value TDF4. The embodiment does not limit the calculation algorithm of the compensation value. For example, the compensation value circuit 225 may use a known algorithm or other algorithms to convert the total degradation value TDF4 into the compensation value CV4. For another example, the compensation value circuit 225 can obtain the compensation value CV4 from a lookup table based on the total degradation value TDF4. The compensation circuit 226 is coupled to the processing circuit 210 to receive the sub-pixel data stream D2. The compensation circuit 226 is coupled to the compensation value circuit 225 to receive the compensation value CV4. In step S560, the compensation circuit 226 compensates the current sub-pixel data in the sub-pixel data stream D2 based on the compensation value CV4 to generate the compensated current sub-pixel data to the display module 10. For example, the compensation circuit 226 may add the compensation value CV4 to the current sub-pixel data in a compensated sub-pixel data stream D2 to generate the compensated current sub-pixel data to the display module 10.
The compensation value circuit 225 generates the compensation value CV4 corresponding to the current sub-pixel data based on the total degradation value TDF4. The accumulation speed adjustment circuit 227 adjusts the accumulation speed weight W to the multiplication circuit 222 based on the compensation value CV4. The compensation circuit 226 compensates the current sub-pixel data in the sub-pixel data stream D2 based on the compensation value CV4 to generate the compensated current sub-pixel data to the display module 10. For example, the compensation circuit 226 may add the compensation value CV4 to the current sub-pixel data in the compensated sub-pixel data stream D2 so as to generate the compensated current sub-pixel data to the display module 10. That is, the compensated sub-pixel data stream D3 may use the compensation region CR for the additional compensation current applied to the degraded sub-pixel. However, the upscaling space (compensation region CR) of the compensated current sub-pixel data is limited.
In an embodiment, the accumulation speed adjustment circuit 227 adjusts the accumulation speed weight W to be the first weight value, in response to the check result indicating that the margin of the compensation value CV4 in the compensation region CR corresponding to any sub-pixel data in the image frame is greater than the first threshold value. The first threshold value may be determined according to actual design. The accumulation speed adjustment circuit 227 adjusts the accumulation speed weight W to be the second weight value less than the first weight value, in response to the check result indicating that the margin of the compensation value CV4 in the compensation region CR corresponding to any sub-pixel data in the image frame is less than the first threshold value. The first weight value and the second weight value may be determined according to actual design. For example, the first weight value is 1, and the second weight value is a positive number less than 1.
In another embodiment, the accumulation speed adjustment circuit 227 adjusts the accumulation speed weight W to be the second weight value, in response to the check result indicating that the margin of the compensation value CV4 in the compensation region CR corresponding to any sub-pixel data in the image frame is less than the first threshold value and greater than the second threshold value. The first threshold value and the second threshold value may be determined according to actual design. The first threshold value is greater than the second threshold value. The accumulation speed adjustment circuit 227 adjusts the accumulation speed weight W to be the third weight value less than the second weight value, in response to the check result indicating that the margin of the compensation value CV4 in the compensation region CR corresponding to any sub-pixel data in the image frame is less than the second threshold value. The second weight value and the third weight value may be determined according to actual design.
For example,
In the implementation example of “Local”, the accumulation speed weight W corresponding to different sub-pixel data in the same image frame may be different. In an embodiment, the accumulation speed adjustment circuit 224 may adjust the accumulation speed weight W corresponding to the current sub-pixel data to be the first weight value, in response to the check result indicating that the margin of the total degradation value TDF4 in the total degradation value range corresponding to the current sub-pixel data is greater than the first threshold value. The first threshold value may be determined according to actual design. The accumulation speed adjustment circuit 224 may adjust the accumulation speed weight W corresponding to the current sub-pixel data to be the second weight value less than the first weight value, in response to the check result indicating that the margin of the total degradation value TDF4 in the total degradation value range corresponding to the current sub-pixel data is less than the first threshold value. The first weight value and the second weight value may be determined according to actual design. For example, the first weight value is 1, and the second weight value is a positive number less than 1. The accumulation speed weight W corresponding to at least one adjacent sub-pixel data near the current sub-pixel data in the image frame is adjusted to be the third weight value less than the first weight value and greater than the second weight value, in response to the accumulation speed weight W corresponding to the current sub-pixel data being adjusted to the second weight value.
Please refer to
In the implementation example of “local”, the accumulation speed weight W corresponding to the different sub-pixel data in the same image frame may be different. In an embodiment, the accumulation speed adjustment circuit 227 may adjust the accumulation speed weight W corresponding to the current sub-pixel data to be the first weight value, in response to the check result indicating that the margin of the compensation value CV4 in the compensation region CR corresponding to the current sub-pixel data is greater than the first threshold value. The first threshold value may be determined according to actual design. The accumulation speed adjustment circuit 227 may adjust the accumulation speed weight W corresponding to the current sub-pixel data to be the second weight value less than the first weight value, in response to the check result indicating that the margin of the compensation value CV4 in the compensation region CR corresponding to the current sub-pixel data is less than the first threshold value. The first weight value and the second weight value may be determined according to actual design. For example, the first weight value is 1, and the second weight value is a positive number less than 1. The accumulation speed weight W corresponding to at least one adjacent sub-pixel data near the current sub-pixel data in the image frame is adjusted to be the third weight value less than the first weight value and greater than the second weight value, in response to the accumulation speed weight W corresponding to the current sub-pixel data being adjusted to the second weight value. For example, referring to
To sum up, the above-mentioned embodiments apply “dynamic decay factor accumulate speed” to overcome the technical issue of color shift in general compensation algorithms. If the accumulation speed weight W is “1” (the accumulation speed is 100%), the sub-pixel degradation may be compensated to return the brightness of the sub-pixel to the target brightness. The above-mentioned embodiments may continuously check the margin of the total degradation value TDF4 in the total degradation value range and/or continuously check the margin of the compensation region CR. Based on the check results, the accumulation speed weight W (the accumulation speed of the degradation value) may be adjusted to slow down the saturation of the compensation region CR (and/or slow down the saturation of the total degradation value range of the total degradation value TDF4). In addition, the pixel degradation compensation circuit may slow down the accumulation speed of the total degradation value (reduce the additional compensation current for the sub-pixel) according to the situation to prolong the life of the sub-pixel.
Although the disclosure has been described with reference to the embodiments above, the embodiments are not intended to limit the disclosure. Any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the disclosure. Therefore, the scope of the disclosure shall be defined in the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
9230472 | Bae | Jan 2016 | B2 |
9779655 | Bae | Oct 2017 | B2 |
9898961 | Jeong et al. | Feb 2018 | B2 |
10163389 | An | Dec 2018 | B2 |
10943541 | Tan | Mar 2021 | B1 |
11164543 | Gao | Nov 2021 | B1 |
11244612 | Ok | Feb 2022 | B2 |
11398173 | Han | Jul 2022 | B2 |
11670231 | Ok | Jun 2023 | B2 |
20150187259 | Jeong et al. | Jul 2015 | A1 |
20170162103 | An | Jun 2017 | A1 |
20200372861 | Ok et al. | Nov 2020 | A1 |
20210150964 | Li | May 2021 | A1 |
20220130332 | Ok et al. | Apr 2022 | A1 |
20220208056 | Baek | Jun 2022 | A1 |
Number | Date | Country |
---|---|---|
104751785 | Jul 2017 | CN |
111986618 | Nov 2020 | CN |
Entry |
---|
“Office Action of Taiwan Counterpart Application”, issued on Apr. 3, 2024, p. 1-p. 8. |