Granted Patent B2

US 12,307,981 · App. 18/328,329 · Granted May 20, 2025

Inventors: Shereef Shehata (San Ramon, CA); Jim C Chou (San Jose, CA)

Assignee: Apple Inc.

G09G3/3291G09G2310/027G09G2320/0233

Abstract

Claims (72)

1. An electronic device, comprising:

a display panel comprising a plurality of display pixels;

an image source configured to provide image data; and

image processing circuitry configured to:

receive a brightness level of the display panel;

receive the image data configured to be displayed by the plurality of display pixels, wherein the image data comprises gray level data for a first display pixel of the plurality of display pixels;

convert the gray level data to voltage data based on the brightness level;

determine a compensation for the voltage data based on a global voltage compensation value and a local voltage compensation value, wherein the global voltage compensation value is configured to compensate for non-uniformities occurring at a first spatial frequency and the local voltage compensation value is configured to compensate for non-uniformities occurring at a second spatial frequency, and wherein the second spatial frequency is greater than the first spatial frequency;

apply the compensation to the voltage data to generate compensated voltage data; and

convert the compensated voltage data into compensated gray level data for the first display pixel, wherein converting the compensated voltage data comprises compressing a voltage domain range of the compensated voltage data.

2. The electronic device of claim 1 , wherein the image processing circuitry is configured to determine the compensation by:

retrieving a plurality of global compensation maps; and

determining the global voltage compensation value by interpolating or extrapolating between a first global compensation map of the plurality of global compensation maps and a second global compensation map of the plurality of global compensation maps.

3. The electronic device of claim 2 , wherein the image processing circuitry is configured to determine the compensation by:

determining a gain value based on the voltage data;

applying the gain value to a local compensation map; and

determining the local voltage compensation value based on the local compensation map and a portion of the display panel.

4. The electronic device of claim 3 , wherein the local compensation map comprises a higher resolution than the first global compensation map or the second global compensation map.

5. The electronic device of claim 1 , wherein the image processing circuitry is configured to convert the gray level data to the voltage data by:

determining a gray-to-voltage lookup table based on the brightness level, wherein the gray-to-voltage lookup table comprises a zero emission region, a first region, a second region, and a third region, and wherein each region comprises uniform spacing between entries.

6. The electronic device of claim 5 , wherein the image processing circuitry is configured to:

determine that the gray level data is within the first region, the second region, or the third region; and

interpolate within the first region, the second region, or the third region to generate the voltage data.

7. The electronic device of claim 1 , wherein the image processing circuitry is configured to receive the brightness level by:

receiving a temperature value of the display panel; or

receiving a current-to-voltage curve of the first display pixel from sensing circuitry.

8. The electronic device of claim 7 , wherein the image processing circuitry is configured to:

retrieve calibration data in response to receiving the temperature value, wherein the calibration data comprises one or more pre-characterized current-to-voltage curves at a respective anchor temperature;

fit the calibration data to a brightness-to-current curve using one or more segments;

convert the brightness-to-current curve to generate an additional current-to-voltage curve; and

update a gray level-to-voltage lookup table and a voltage-to-gray level lookup table based on the additional current-to-voltage curve.

9. The electronic device of claim 7 , wherein the image processing circuitry is configured to:

update a gray level-to-voltage lookup table and a voltage-to-gray level lookup table based on the received current-to-voltage curve.

10. The electronic device of claim 7 , wherein the image processing circuitry is configured to update a lookup table for converting the voltage data to the gray level data based on the current-to-voltage curve of the first display pixel.

11. The electronic device of claim 1 , wherein compressing the voltage domain range of the compensated voltage data comprises:

interpolating within a threshold voltage range to determine the compensated gray level data; or

extrapolating from the threshold voltage range to determine the compensated gray level data.

12. Processing circuitry, comprising:

first conversion circuitry configured to convert source image data corresponding to a display pixel of a plurality of display pixels of an electronic display from gray level data of the source image data to voltage data;

non-uniformity correction circuitry configured to generate compensated voltage data based on the voltage data, a global compensation map, and a local compensation map, wherein the global compensation map is configured to compensate for non-uniformities occurring at a first spatial frequency and the local compensation map is configured to compensate for non-uniformities occurring at a second spatial frequency, and wherein the second spatial frequency is greater than the first spatial frequency; and

second conversion circuitry configured to convert the compensated voltage data to digital code corresponding to the display pixel by:

receiving an indication of operating characteristics of a display panel;

compressing a voltage domain range of the compensated voltage data based on the operating characteristics of the display panel; and

converting the compensated voltage data to the digital code.

13. The processing circuitry of claim 12 , wherein the first conversion circuitry is configured to convert the source image data by:

receiving a temperature or current-to-voltage data from sensing circuitry;

updating a brightness-to-voltage relationship based on the temperature or the current-to-voltage data; and

determining the voltage data based on the brightness-to-voltage relationship.

14. The processing circuitry of claim 12 , wherein the non-uniformity correction circuitry is configured to generate the compensated voltage data by:

determining a global voltage compensation based on the global compensation map in a first compensation mode;

determining a local voltage compensation based on the local compensation map in a second compensation mode; and

determining a compensation based on the global compensation map and the local compensation map in a third compensation mode, wherein the global compensation map is a lower resolution than the local compensation map.

15. The processing circuitry of claim 12 , wherein the second conversion circuitry is configured to compress the voltage domain range by:

determining a threshold voltage range based on the operating characteristics.

16. A method comprising:

receiving, via processing circuitry, gray level data and operating characteristics of a display panel;

converting, via the processing circuitry, the gray level data to voltage data;

determining, via the processing circuitry, a compensation based on a global voltage compensation value and a local voltage compensation value, wherein the global voltage compensation value is configured to compensate for non-uniformities occurring at a first spatial frequency and the local voltage compensation value is configured to compensate for non-uniformities occurring at a second spatial frequency, and wherein the second spatial frequency is greater than the first spatial frequency;

generating, via the processing circuitry, compensated image data by applying the compensation to the gray level data; and

converting, via the processing circuitry, the compensated image data to compensated gray level data by compressing a voltage domain range of the compensated image data based on the operating characteristics of the display panel.

17. The method of claim 16 , wherein the operating characteristics of the display panel comprise a temperature value of the display panel, a current-to-voltage relationship of the display panel, a bit-depth of the display panel, and foveation data of the display panel.

18. The method of claim 16 , wherein compressing the voltage domain range comprises:

interpolating between voltage values within a threshold voltage range to convert the compensated image data to the compensated gray level data, wherein the threshold voltage range is determined based on the operating characteristics; or

extrapolating from the threshold voltage range to convert the compensated image data to the compensated gray level data.

19. The method of claim 16 , wherein determining, via the processing circuitry, the compensation comprises:

determining the compensation based a global compensation map based on a first compensation mode;

determining the compensation based on a local compensation map based on a second compensation mode; or

determining the compensation based on both the global compensation map and the local compensation map based on a third compensation mode.

20. The method of claim 19 , wherein determining the compensation based on the local compensation map comprises:

up-sampling the local compensation map based on the operating characteristics;

reading a first line of the local compensation map based on the operating characteristics; and

skipping a second line of the local compensation map based on the operating characteristics.

Assignments (1)

Continuity (1)

References Cited (11)