Techniques for avoiding and remedying DC bias buildup on a flat panel variable refresh rate display

Patent metadata

Field	Value
Publication number	US-9711099-B2
Application number	US-201414190559-A
Country	US
Kind code	B2
Filing date	Feb 26, 2014
Priority date	Feb 26, 2014
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A method for driving a display panel having a variable refresh rate is disclosed. The method comprises receiving a current input frame from an image source. Next, it comprises determining a number of re-scanned frames to insert between the current input frame and a subsequent input frame, wherein the re-scanned frames repeat the input frame, and wherein the number of re-scanned frames depends on the minimum refresh interval (MRI) of the display panel. Further, it comprises calculating respective intervals at which to insert the re-scanned frames between the current input frame and the subsequent input frame. Subsequently, it comprises determining if a charge accumulation in pixels of the display panel has crossed over a predetermined threshold value. Finally, responsive to a determination that the charge accumulation has crossed over a predetermined threshold value, it comprises performing a counter-measure to remediate the charge accumulation.

First claim

What is claimed is:

1. A method for driving a display panel having a variable refresh rate, said method comprising:
receiving a current input frame from an image source;
determining a number of re-scanned frames to insert between said current input frame and a subsequent input frame, wherein said re-scanned frames repeat said input frame, and wherein said determining depends on a minimum refresh interval (MRI) of said display panel;
calculating respective intervals at which to insert said re-scanned frames between said current input frame and said subsequent input frame;
determining if a charge accumulation in pixels of said display panel has crossed over a predetermined threshold value; and
responsive to a determination that said charge accumulation has crossed over a predetermined threshold value, performing a counter-measure to remediate said charge accumulation.

2. The method of claim 1 , wherein said counter-measure is selected from a group consisting of: reducing said number of re-scanned frames by one, dropping said current input frame, and increasing said number of re-scanned frames by one.

3. The method of claim 2 , wherein said performing comprises:
performing said reducing;
performing said dropping instead of said reducing if said performing said reducing is not sufficient; and
performing said increasing instead of said dropping if said performing said dropping is not sufficient.

4. The method of claim 1 , further comprising:
responsive to a determination that said charge accumulation is below said predetermined threshold value, scanning said current input frame for display on said display panel and inserting said number of re-scanned frames at said respective intervals between said current input frame and said subsequent input frame, wherein said inserting is operable to prevent charge accumulation in said display panel.

5. The method of claim 1 , wherein said charge accumulation is a result of a frame pattern comprising alternating frames of differing polarities, wherein frames of positive polarity within said frame pattern are of a different time duration than frames of negative polarity, and wherein an imbalance in said frame pattern results in an accumulation of charge in pixels of said display panel, and wherein said counter-measure is operable to reverse a polarity pattern of said frame pattern in order to remedy said charge accumulation.

6. The method of claim 1 , wherein said performing comprises:
reducing said number of re-scanned frames by one;
scanning said current input frame for display on said display panel; and
inserting a reduced number of re-scanned frames between said current input frame and said subsequent input frame.

7. The method of claim 6 , further comprising:
determining if said reduced number of re-scanned frames is even;
responsive to a determination that said reduced number of re-scanned frames is even, enforcing an even number of re-scanned frames between said current input frame and said subsequent frame; and
responsive to a determination that said reduced number of re-scanned frames is odd, enforcing an odd number of re-scanned frames between said current input frame and said subsequent frame.

8. The method of claim 1 , wherein said performing further comprises:
dropping said current input frame; and
waiting to receive a subsequent input frame from said image source.

9. The method of claim 8 , further comprising:
re-scanning said current input frame for display on said display panel until said subsequent input frame is received from said image source.

10. The method of claim 1 , wherein said performing comprises:
increasing the number of re-scans by one;
scanning said current input frame for display on said display panel; and
inserting an increased number of re-scanned frames between said current input frame and said subsequent input frame.

11. The method of claim 10 , further comprising:
determining if said increased number of re-scanned frames is even;
responsive to a determination that said increased number of re-scanned frames is even, enforcing an even number of re-scanned frames between said current input frame and said subsequent frame; and
responsive to a determination that said increased number of re-scanned frames is odd, enforcing an odd number of re-scanned frames between said current input frame and said subsequent frame.

12. A non-transitory computer-readable storage medium having stored thereon, computer executable instructions that, if executed by a computer system cause the computer system to perform a method for driving a display panel having a variable refresh rate, said method comprising:
receiving a current input frame from an image source;
determining a number of re-scanned frames to insert between said current input frame and a subsequent input frame, wherein said re-scanned frames repeat said input frame, and wherein said determining depends on a minimum refresh interval (MRI) of said display panel;
calculating respective intervals at which to insert said re-scanned frames between said current input frame and said subsequent input frame;
determining if a charge accumulation in pixels of said display panel has crossed over a predetermined threshold value; and
responsive to a determination that said charge accumulation has crossed over a predetermined threshold value, performing a counter-measure to remediate said charge accumulation.

13. The computer-readable storage medium of claim 12 , wherein said counter-measure is selected from a group consisting of: reducing said number of re-scanned frames by one, dropping said current input frame, and increasing said number of re-scanned frames by one.

14. The computer-readable storage medium of claim 13 , wherein said performing comprises:
performing said reducing;
performing said dropping instead of said reducing if said performing said reducing is not sufficient; and
performing said increasing instead of said dropping if said performing said dropping is not sufficient.

15. The computer-readable storage medium of claim 12 , further comprising:
responsive to a determination that said charge accumulation is below said predetermined threshold value, scanning said current input frame for display on said display panel, and inserting said number of re-scanned frames at said intervals between said current input frame and said subsequent input frame, wherein said inserting is operable to prevent charge accumulation in said display panel.

16. The computer-readable storage medium of claim 12 , wherein said charge accumulation is a result of a frame pattern comprising alternating frames of differing polarities, wherein frames of positive polarity within said frame pattern are of a different time duration than frames of negative polarity, and wherein an imbalance in said frame pattern results in an accumulation of charge in pixels of said display panel, and wherein said counter-measure is operable to reverse a polarity pattern of said frame pattern in order to remedy said charge accumulation.

17. The computer-readable storage medium of claim 12 , wherein said performing comprises:
reducing said number of re-scanned frames by one;
scanning said current input frame for display on said display panel; and
inserting a reduced number of re-scanned frames between said current input frame and said subsequent input frame.

18. The computer-readable storage medium of claim 17 , wherein said performing further comprises:
determining if said reduced number of re-scanned frames is even;
responsive to a determination

Assignees

• Nvidia Corp

Inventors

• Bloks Rudolf
• Schutten Robert
• Verbeure Tom

Classifications

• G09G3/3614 Primary

  Control of polarity reversal in general · CPC title

• G09G2320/02

  Improving the quality of display appearance · CPC title

• G09G3/3618

  with automatic refresh of the display panel using sense/write circuits · CPC title

• G09G2320/0204

  Compensation of DC component across the pixels in flat panels · CPC title

• G09G2310/08

  Details of timing specific for flat panels, other than clock recovery · CPC title