IP Library › Granted Patent US 11,699,377
Granted Patent B2
US 11,699,377 · App. 17/321,073 · Granted Jul 11, 2023

Temperature-based pixel drive compensation

Inventor: Mahesh B. Chappalli (San Jose, CA)
Assignee: Apple Inc.
G09G3/2007G09G5/06G09G5/10G09G5/393G09G2320/041G09G2320/0626G09G2320/0693G09G2330/021G09G2340/16G09G2350/00G09G2360/122
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Quick Facts
Patent No.
US 11,699,377
App. No.
17/321,073
Granted
Jul 11, 2023
Kind
B2
Abstract

Image data for a current image frame may be compensated for transient response variations due to variations in display panel temperatures at various positions of the display panel by performing pixel drive compensation. The pixel drive compensation may be performed based at least in part upon display panel temperatures at various portions of the display panel. In this way, drive compensation corresponding to various temperature variations in a display panel may be implemented.

Claims (51)

1. Pixel drive compensation circuitry, comprising:

pixel modification circuitry, wherein the pixel modification circuitry is configured to:

modify first input pixel data based at least in part on second input pixel data and a temperature associated with the first input pixel data to produce a multi-frame history; and

perform a write-back of the multi-frame history to memory communicatively coupled to the pixel modification circuitry; and

drive compensation circuitry, wherein the drive compensation circuitry is configured to:

retrieve the multi-frame history from the memory; and

determine a drive compensation value based at least in part on third input pixel data, a temperature associated with the third input pixel data, and the multi-frame history, wherein an electronic display is configured to drive a pixel of a display panel based at least in part on the drive compensation value.

2. The pixel drive compensation circuitry of claim 1 , wherein the first input pixel data corresponds to a first image frame displayed on the display panel at a first time, wherein the second input pixel data corresponds to a second image frame displayed on the display panel at a second time before the first time, and wherein the third input pixel data corresponds to a third image frame displayed on the display panel at a third time after the first time.

3. The pixel drive compensation circuitry of claim 1 , wherein the first input pixel data comprises a gray level of the pixel of the display panel.

4. The pixel drive compensation circuitry of claim 1 , wherein the pixel modification circuitry comprises a plurality of sets of lookup tables, each of the plurality of sets of lookup tables associated with a temperature value of a vector of temperatures, wherein the pixel modification circuitry is configured to modify the first input pixel data based at least in part on an interpolation of the first input pixel data, the second input pixel data, and an output of a particular set of pixel modification lookup tables of plurality of sets of lookup tables that corresponds to a temperature value of the vector of temperatures that is closest to the temperature associated with the first input pixel data.

5. The pixel drive compensation circuitry of claim 4 , wherein each of plurality of sets of lookup tables comprises a first set of lookup tables and a second set of lookup tables, wherein the first set of lookup tables comprises first pixel modification values calibrated based at least in part on a first range of a characteristic of the display panel, wherein the second set of lookup tables comprises second pixel modification values calibrated based at least in part on a second range of the characteristic of the display panel.

6. The pixel drive compensation circuitry of claim 5 , wherein the characteristic comprises a brightness of the display panel.

7. The pixel drive compensation circuitry of claim 1 , wherein the drive compensation circuitry comprises a plurality of sets of lookup tables, each of the plurality of sets of lookup tables associated with a temperature value of a vector of temperatures, wherein the drive compensation circuitry is configured to determine the drive compensation value based at least in part on an interpolation of the third input pixel data, the multi-frame history, and an output of a particular set of drive compensation lookup tables of the plurality of sets of lookup tables that corresponds to a temperature value of the vector of temperatures that is closest to the temperature associated with the third input pixel data.

8. The pixel drive compensation circuitry of claim 7 , wherein the interpolation comprises a Barycentric interpolation, a hybrid Barycentric-bilinear interpolation, or a combination thereof.

9. The pixel drive compensation circuitry of claim 1 , wherein the pixel modification circuitry is configured to perform the write-back in response to determining that a pixel modification mode of the pixel drive compensation circuitry is enabled and that the second input pixel data corresponds to a gray level of zero.

10. The pixel drive compensation circuitry of claim 9 , wherein the pixel modification circuitry is configured to, in response to determining that the pixel modification mode of the pixel drive compensation circuitry is disabled or that the second input pixel data corresponds to a non-zero gray level or in response to a starting condition, perform a write-back of the first input pixel data to the memory without modification, wherein the starting condition corresponds to a first frame to begin generation of the multi-frame history.

11. The pixel drive compensation circuitry of claim 1 , wherein the pixel modification circuitry is configured to modify the first input pixel data in response to determining that a pixel modification mode of the pixel drive compensation circuitry is enabled and that the second input pixel data corresponds to a gray level of zero.

12. The pixel drive compensation circuitry of claim 1 , comprising temperature identification circuitry, configured to:

identify a grid of temperature values spanning the display panel; and

identify the temperature associated with the first input pixel data and the temperature associated with the third input pixel data based upon the grid of temperature values.

13. The pixel drive compensation circuitry of claim 12 , wherein the temperature identification circuitry is configured to:

identify a tile made up of four grid points of the grid of temperature values;

interpolate, from temperature values associated with the four grid points, a tile temperature for the tile; and

use the tile temperature as the temperature associated with the first input pixel data, the temperature associated with the third input pixel data, or both.

14. The pixel drive compensation circuitry of claim 12 , wherein the grid is defined by two independent arrays of grid points and the grid points are non-uniformly spaced to enable finer resolution at various positions within the grid.

15. A method for operating a pixel drive compensation circuitry implemented in an electronic device, comprising:

modifying first input pixel data based at least in part on second input pixel data and a temperature associated with the first input pixel data to produce a multi-frame history; and

performing a write-back of the multi-frame history to memory communicatively coupled to the pixel drive compensation circuitry;

retrieving the multi-frame history from the memory; and

determining a drive compensation value based at least in part on third input pixel data, a temperature associated with the third input pixel data, and the multi-frame history, wherein an electronic display is configured to drive a pixel of a display panel based at least in part on the drive compensation value.

16. The method of claim 15 , comprising:

identifying a grid of grid points spatially spanning an electronic display panel, each grid point associated with a temperature value;

identifying tiles within the grid, each tile made up of four of the grid points;

interpolating, from temperature values associated with grid points making up each tile, tile temperature values for each tile in the grid; and

performing pixel drive compensation based at least in part upon the tile temperature values for each tile in the grid, by selecting compensation data derived from one or more lookup tables of a plurality of lookup tables, wherein the one or more lookup tables are selected based upon at least one of the tile temperature values.

17. The method of claim 16 , comprising:

dynamically selecting the compensation data for each tile based upon a temperature corresponding to that tile.

18. An electronic device comprising:

a display panel;

a memory; and

a display pipeline coupled between the memory and the display panel, wherein the display pipeline comprises:

pixel drive compensation circuitry, comprising pixel modification circuitry, wherein the pixel modification circuitry is configured to:

modify first input pixel data based at least in part on second input pixel data and a temperature associated with the first input pixel data to produce a multi-frame history and a temperature associated with the first input pixel data to produce a multi-frame history; and

perform a write-back of the multi-frame history to memory

communicatively coupled to the pixel modification circuitry; and

drive compensation circuitry, wherein the drive compensation circuitry is configured to:

retrieve the multi-frame history from the memory; and

determine a drive compensation value based at least in part on third input pixel data, a temperature associated with the third input pixel data, and the multi-frame history, wherein an electronic display is configured to drive a pixel of a display panel based at least in part on the drive compensation value;

wherein the display pipeline is configured to provide the modified first input pixel data for rendering at the display panel.

19. The electronic device of claim 18 , wherein the temperature associated with the first input pixel data comprises a tile temperature interpolated from temperature values associated with four grid points of a grid of grid points spanning a display panel.

20. The electronic device of claim 19 , wherein the pixel drive compensation circuitry is configured to select particular compensation values from a plurality of available compensation values based upon a comparison of temperatures associated with sets of lookup tables used to derive the plurality of available compensation values and the tile temperature.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded May 18, 2021
From: CHAPPALLI, MAHESH B.
To: APPLE INC.
Reel/Frame 056271/0776 →
Continuity (2)
Provisional Application 63078284 · Sep 14, 2020
Related Publication 20220084454A1 · Mar 17, 2022