PIXEL SIGNAL COMPENSATION FOR A DISPLAY PANEL

• US 20170018219A1
• Filed: 12/17/2015
• Published: 01/19/2017
• Est. Priority Date: 07/16/2015
• Status: Active Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: FAN JIANG, Shih-Chyuan, BROWN, James E. C., WANG, Chaohao, SACCHETTO, Paolo, ALBRECHT, Marc, TANN, Christopher P., TANG, Howard H., GE, Zhibing
• Granted Patent: US 10,276,085 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G09G 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165

Abstract

This application relates to systems, methods, and apparatus for compensating voltage for pixels of a display panel based on the location of the pixels within the display panel. An amount of voltage compensation is assigned to each pixel or a group of pixels within the display panel in accordance with a calibration of the display panel. During operation of the display panel, pixel data is generated for a location of the display panel, and the pixel data is modified according to the amount of voltage compensation corresponding to the location. By modifying the pixel data in this way, spatial variations in voltage across the display panel can be mitigated in order to reduce the occurrence of certain display artifacts at the display panel.

Claims

1. A method for compensating a pixel signal based on a location of a pixel within a pixel array of a display panel, the method comprising:

by a logic component of the display panel;

selecting a compensation value for the pixel signal according to a location of the pixel within the pixel array, wherein the compensation value is selected from a plurality of compensation values that correspond to different locations within the pixel array; and

compensating the pixel signal according to the compensation value.

2. The method of claim 1, wherein selecting the compensation value comprises:

identifying a voltage compensation value for a voltage buffer connected to the pixel within the pixel array, wherein the voltage compensation value is selected from a plurality of voltage compensation values.

3. The method of claim 1, wherein selecting the compensation value comprises:

identifying a gray level adjustment value for the pixel within the pixel array, wherein the gray level adjustment value is selected from a plurality of gray level adjustment values.

4. The method of claim 1, wherein each compensation value of the plurality of compensation values correspond to a segment of the pixel array that includes multiple pixels.

5. The method of claim 1, wherein the compensation value of the plurality of compensation values is selected based on a pixel polarity value.

6. The method of claim 1, wherein the pixel array includes one or more organic light emitting diodes.

7. A display controller, comprising:

a memory configured to store correspondence data between pixel compensation values and different locations on a display panel;

a pixel input configured to sequentially receive a first pixel signal and a second pixel signal for a first pixel and a second pixel, respectively, of the display panel; and

a logic component configured to (i) access the correspondence data and (ii) compensate the first pixel signal and the second pixel signal differently based on a location of each of the first pixel and the second pixel on the display panel.

8. The display controller of claim 7, wherein the first pixel signal and the second pixel signal correspond to reference voltage signals for a voltage buffer of the display panel.

9. The display controller of claim 7, wherein the pixel compensation values are gray level adjustment values for the first pixel signal and the second pixel signal.

10. The display controller of claim 7, wherein the different locations on the display panel correspond to groups of pixels within a pixel array of the display panel.

11. The display controller of claim 7, wherein the memory is further configured to store a correspondence between the pixel compensation values and different types of inversion schemes that can be employed by the display controller.

12. The display controller of claim 7, wherein the memory is further configured to store correspondence between the pixel compensation values and different polarities for the first pixel and the second pixel on the display panel.

13. The display controller of claim 7, wherein the logic component includes:

a position tracker for determining a location of the first pixel and the second pixel based in part on a pixel clock input to the position tracker.

14. A computing device, comprising:

a display panel comprising a pixel array;

a graphics processor configured to generate a pixel signal for each pixel of the pixel array; and

a display driver configured to determine a location of each pixel in the pixel array and compensate a voltage of the pixel signal according to the location of the pixel in the pixel array to reduce flicker occurring at the display panel.

15. The computing device of claim 14, further comprising:

a memory configured to store at least one lookup table that includes a correspondence between locations of pixels in the pixel array and a voltage compensation value for each location.

16. The computing device of claim 15, wherein the at least one lookup table includes a plurality of locations in the pixel array, and each location of the plurality of locations corresponds to a group of pixels on the display panel.

17. The computing device of claim 14, wherein the display driver is further configured to compensate the voltage of the pixel signal according to a polarity of the pixel.

18. The computing device of claim 14, wherein the display driver is further configured to compensate the voltage of the pixel signal according to a type of inversion scheme executing at the display panel.

19. The computing device of claim 14, wherein the display driver is further configured to compensate the voltage of the pixel signal according to a type of inversion scheme executing at the display panel.

20. The computing device of claim 14, wherein the pixel includes an organic light emitting diode that is operable in the display panel at different polarities.