Liquid crystal display with temporal black point

• US 20050248520A1
• Filed: 10/15/2004
• Published: 11/10/2005
• Est. Priority Date: 05/04/2004
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Daly, Scott J., Feng, Xiao-fan
• Granted Patent: US 7,872,631 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0613 The adjustment depending on the type of the information to be displayed
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0653 Controlling or limiting the speed of brightness adjustment of the illumination source
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/10 Dealing with defective pixels
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/2081 with combination of amplitude modulation and time modulation space and time error diffusion G09G3/2066
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A backlit display with improved dynamic range.

Claims

1. A method for displaying an image on a liquid crystal display comprising:

(a) illuminating a first pixel at a first non-zero illumination level during an initial frame;

(b) illuminating said first pixel at a second non-zero illumination level during a subsequent frame, wherein said subsequent frame is temporally later than said initial frame;

(c) wherein said first pixel is selectively decreased in illumination to an intermediate illumination level, based upon an estimation of temporal blur of said first pixel, after illuminating said first pixel during said initial frame and before illuminating said first pixel during said subsequent frame.¹

¹ Novelty resides in the use of temporal blur.

2. The method of claim 1 wherein said intermediate illumination level is less than that which said first pixel is otherwise illuminated to achieve said second illumination level.

3. The method of claim 1 wherein said intermediate illumination level is substantially zero.

4. The method of claim 1 wherein said liquid crystal display includes a plurality of addressable light emitting elements.

5. The method of claim 1 wherein said temporal blur is based upon moving edges.

6. The method of claim 1 wherein said temporal blur is based upon content of at least one of said frames.

7. A method for displaying an image on a liquid crystal display comprising:

(a) illuminating a first pixel at non-zero illumination levels during a plurality of different frames;

(b) wherein said first pixel is decreased in illumination to a decreased illumination level based upon an estimation of temporal blur of said first pixel.²

² The novelty resides in the use of temporal blur as a measure.

8. The method of claim 7 wherein said liquid crystal display includes a plurality of addressable light emitting elements.

9. The method of claim 7 wherein said decreased illumination level is substantially zero.

10. The method of claim 7 wherein said temporal blur is based upon moving edges.

11. The method of claim 7 wherein said temporal blur is based upon content of at least one of said frames.

12. A method for displaying an image on a liquid crystal display comprising:

(a) illuminating a first pixel at non-zero illumination levels during a plurality of different frames;

(b) wherein said first pixel is periodically decreased in illumination to a value substantially near zero based upon an estimation of the temporal blur of said first pixel.³

³ The novelty resides in the use of temporal blur as a measure.

13. The method of claim 12 wherein said value is less than that which said first pixel is otherwise illuminated to achieve a next frame.

14. The method of claim 12 wherein said value is substantially zero.

15. The method of claim 12 wherein said liquid crystal display includes a plurality of addressable light emitting elements.

16. The method of claim 12 wherein said temporal blur is based upon moving edges.

17. The method of claim 12 wherein said temporal blur is based upon content of at least one of said frames.

18. A method for displaying an image on a liquid crystal display comprising:

(a) illuminating a first pixel at a first non-zero illumination level during an initial frame;

(b) illuminating said first pixel at a second non-zero illumination level during a subsequent frame, wherein said subsequent frame is temporally later than said initial frame;

(c) wherein said first pixel is selectively decreased in illumination to an intermediate illumination level, based upon the content of a portion of said image, after illuminating said first pixel during said initial frame and before illuminating said first pixel during said subsequent frame.⁴

⁴ The novelty resides in the use of image content as a measure.

19. The method of claim 18 wherein said content includes texture of said image.

20. The method of claim 18 wherein said content includes spatial frequency of said image.

21. The method of claim 18 wherein said content includes motion estimation of said image.

22. The method of claim 18 wherein said content includes segmentation of said image.

23. The method of claim 18 wherein said content includes moving edges of said image.

24. The method of claim 18 wherein said content includes high frequency aspects of said image.

25. A method for displaying an image on a liquid crystal display comprising:

(a) illuminating a first pixel at non-zero illumination levels during a plurality of different frames;

(b) wherein said first pixel is decreased in illumination to a decreased illumination level based upon the content of a portion of said image.⁵

⁵ The novelty resides in the use of content as a measure.

26. A method for displaying an image on a liquid crystal display comprising:

(a) illuminating a first pixel at non-zero illumination levels during a plurality of different frames;

(b) wherein said first pixel is periodically decreased in illumination to a value substantially near zero based upon the content of a portion of said image.⁶

⁶ The novelty resides in the use of content as a measure.

27. A method for displaying an image on a liquid crystal display comprising:

(a) illuminating a first pixel at a first non-zero illumination level during an initial frame;

(b) illuminating said first pixel at a second non-zero illumination level during a subsequent frame, wherein said subsequent frame is temporally later than said initial frame;

(c) wherein said first pixel is selectively decreased in illumination to another illumination level, based upon both the spatial frequency content of a portion of said image and the temporal frequency content of a portion of a video including said image, after illuminating said first pixel during said initial frame and before illuminating said first pixel during said subsequent frame.