Display rescan

• US 10,762,866 B2
• Filed: 08/30/2018
• Issued: 09/01/2020
• Est. Priority Date: 08/30/2018
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Morein, Stephen L.
• Primary Examiner(s): Earles, Bryan
• Application Number:
  US16/118,377
• Publication Number:
  US 20200074949A1
• Time in Patent Office: 733 Days
• CPC Class Codes: G09G 2310/0213 controlling the sequence of the scanning lines with respect to the patterns to be displayed, e.g. to save power
• CPC Class Codes: G09G 2310/0237 Switching ON and OFF the backlight within one frame
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

A method and apparatus for updating pixel elements of a display device. The display device comprises a pixel array including a plurality of pixel elements and one or more light sources to illuminate the pixel array at a first instance of time. A data driver is configured to receive a frame of display data corresponding to an image to be displayed on the pixel array at a first instance of time. The data driver scans each row of the pixel array, during a pixel adjustment period prior to the first instance of time, to drive a plurality of first voltages onto the plurality of pixel elements, respectively, based on the received frame. The data driver further rescans a subset of rows of the pixel array, during the pixel adjustment period, to drive second voltages onto respective pixel elements in the subset of rows based on the received frame.

Claims

1. A method, comprising:

receiving a frame of display data corresponding to an image to be displayed on a pixel array at a first instance of time, the pixel array including a plurality of pixel elements arranged in rows and columns;

determining a plurality of target pixel values for the plurality of pixel elements, respectively, based on the received frame;

for each pixel element in the pixel array, determining a target voltage that causes the pixel element to settle at its target pixel value;

selecting at least some of the pixel elements to receive overdrive voltages based on each of the selected pixel elements having at least a threshold change in pixel value between a current pixel value and its target pixel value, wherein the overdrive voltage for a pixel element is different than the target voltage for that pixel element;

scanning each row of the pixel array, during a pixel adjustment period prior to the first instance of time, to drive a plurality of first voltages onto the plurality of pixel elements, respectively, based on the received frame;

rescanning at least a subset of rows of the pixel array, during the pixel adjustment period, to drive second voltages onto respective pixel elements in the subset of rows based on the received frame, wherein the subset of rows to be rescanned is selected based at least in part on the pixel elements selected to receive overdrive voltages; and

activating one or more light sources to illuminate the pixel array at the first instance of time.

2. The method of claim 1, wherein the one or more light sources are deactivated during the pixel adjustment period.

3. The method of claim 1, wherein the scanning comprises:

driving the overdrive voltages onto respective pixel elements in the subset of rows of the pixel array; and

driving the target voltages onto respective pixel elements in each of the remaining rows of the pixel array.

4. The method of claim 1, wherein the rescanning comprises:

driving the target voltages onto respective pixel elements in the subset of rows of the pixel array.

5. The method of claim 1, wherein the image includes a full field-of-view (FFOV) image and a foveal image positioned within the FFOV image, the method further comprising:

for each pixel of the FFOV image, selecting a plurality of pixel elements of the pixel array to display the pixel of the FFOV image;

for each pixel of the foveal image, selecting a respective pixel element of the pixel array to display the pixel of the foveal image; and

selecting the subset of rows based at least in part on the pixel elements selected to display the foveal image.

6. The method of claim 5, wherein each of the first voltages is used to render the FFOV image on respective pixel elements of the pixel array, and wherein at least some of the second voltages are used to render the foveal image on respective pixel elements of the pixel array.

7. The method of claim 6, wherein the scanning comprises:

activating groups of pixel elements in succession, wherein each group of pixel elements includes a plurality of rows of the pixel array; and

driving the first voltages onto respective pixel elements in the plurality of rows, concurrently, for each activated group.

8. The method of claim 6, wherein the rescanning comprises:

activating each row of pixel elements in the subset of rows in succession; and

driving the second voltages onto respective pixel elements in each activated row.

9. The method of claim 6, wherein the scanning is performed at a faster rate than the rescanning.

10. A display device comprising:

a pixel array including a plurality of pixel elements arranged in rows and columns;

a display driver configured to;

receive a frame of display data corresponding to an image to be displayed on the pixel array at a first instance of time;

scan each row of the pixel array, during a pixel adjustment period prior to the first instance of time, to drive a plurality of first voltages onto the plurality of pixel elements, respectively, based on the received frame; and

rescan at least a subset of rows of the pixel array, during the pixel adjustment period, to drive second voltages onto respective pixel elements in the subset of rows based on the received frame;

overdrive circuitry configured to;

determine a plurality of target pixel values for the plurality of pixel elements, respectively, based on the received frame;

for each pixel element in the pixel array, determine a target voltage that causes the pixel element to settle at its target pixel value;

select at least some of the pixel elements to receive overdrive voltages based on each of the selected pixel elements having at least a threshold change in pixel value between a current pixel value and its target pixel value, wherein the overdrive voltage for a pixel element is different than the target voltage for that pixel element; and

select the subset of rows to be rescanned based at least in part on the pixel elements selected to receive overdrive voltages

one or more light sources configured to illuminate the pixel array at the first instance of time.

11. The display device of claim 10, wherein the one or more light sources are deactivated during the pixel adjustment period.

12. The display device of claim 10, wherein the display driver is to scan each row of the pixel array by:

driving the overdrive voltages onto respective pixel elements in the subset of rows of the pixel array; and

driving the target voltages onto respective pixel elements in each of the remaining rows of the pixel array.

13. The display device of claim 10, wherein the display driver is to rescan each row of the pixel array by:

driving the target voltages onto respective pixel elements in the subset of rows of the pixel array.

14. The display device of claim 13, wherein the image includes a full field-of-view (FFOV) image and a foveal image positioned within the FFOV image, wherein the display driver is further configured to:

for each pixel of the FFOV image, select a plurality of pixel elements of the pixel array to display the pixel of the FFOV image;

for each pixel of the foveal image, select a respective pixel element of the pixel array to display the pixel of the foveal image; and

select the subset of rows based at least in part on the pixel elements selected to display the foveal image.

15. The display device of claim 14, wherein each of the first voltages is used to render the FFOV image on respective pixel elements of the pixel array, and wherein at least some of the second voltages are used to render the foveal image on respective pixel elements of the pixel array.

16. The display device of claim 15, wherein the display driver is to scan each row of the pixel array by:

activating groups of pixel elements in succession, wherein each group of pixel elements includes a plurality of rows of the pixel array; and

driving the first voltages onto respective pixel elements in the plurality of rows, concurrently, for each activated group.

17. The display device of claim 15, wherein the display driver is to rescan each row of the pixel array by:

activating each row of pixel elements in the subset of rows in succession; and

driving the second voltages onto respective pixel elements in each activated row.

18. The display device of claim 15, wherein the scan is performed at a faster rate than the rescan.