Liquid crystal display system and method

• US 9,805,666 B2
• Filed: 11/02/2007
• Issued: 10/31/2017
• Est. Priority Date: 11/09/2006
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Hoppenbrouwers, Jurgen Jean Louis, Jak, Martin Jacobus Johan, Van Beek, Wilhelmus Henricus Maria
• Primary Examiner(s): Leiby, Christopher E
• Application Number:
  US12/513,517
• Publication Number:
  US 20100060672A1
• Time in Patent Office: 3,651 Days
• Field of Search: 345204-206, 345211-215, 345 30, 345 50- 55, 345 87-102
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

A display system (1) for generating a picture in accordance with image information (10) derived from a video signal has a light modulation device (20), an illumination device (30) and a control circuit (40) for driving both devices. The algorithm implemented in the control circuit (40) distributes the image information (10) over the light modulation device (20) and the illumination device (30) in order to minimize the power consumption of the display system.

Claims

1. A method for displaying image information in a display system comprising:

determining, from the image information, a maximum pixel luminance in a region of a light modulation device, wherein a light source of an illumination device is configured to illuminate the region of the light modulation device;

selecting a distribution factor based on a predetermined distribution factor function that is configured to select a given distribution factor for a plurality of pixel luminances below a predetermined maximum pixel luminance and is configured to select which one of a plurality of distribution factors larger than the given distribution factor corresponds to the maximum pixel luminance when the maximum pixel luminance is above the predetermined maximum pixel luminance;

calculating a luminance of the light source by applying the selected distribution factor to the maximum pixel luminance and calculating a transmission of the light modulation device for a pixel corresponding to the maximum pixel luminance; and

displaying the maximum pixel luminance at the pixel by configuring the light source of the illumination device to output said luminance of the light source and by configuring the light modulation device to implement the calculated transmission at the pixel.

2. The method of claim 1, wherein the light source is a first light source, wherein the region of the light modulation device is a first region, wherein the maximum pixel luminance is a first maximum pixel luminance, wherein the luminance of the light source is a first light source luminance and wherein the method further comprises:

selecting a second distribution factor, which corresponds to a second maximum pixel luminance in a second region of the light modulation device, based on the predetermined distribution factor function, wherein the second distribution factor is different from the first distribution factor;

calculating a second light source luminance of a second light source of the illumination system that is configured to illuminate the second region by applying the selected second distribution factor to the second maximum pixel luminance and calculating a second transmission of the light modulation device for an other pixel corresponding to the second maximum pixel luminance,

wherein the displaying further comprises displaying the second maximum pixel luminance at the other pixel by configuring the second light source of the illumination device to output said second light source luminance and by configuring the light modulation device to implement the calculated second transmission at the other pixel.

3. The method of claim 1, wherein the applying the selected distribution factor to the maximum pixel luminance comprises scaling a contribution of the maximum pixel luminance to the luminance of the light source with the selected distribution factor.

4. The method of claim 1, wherein the calculating the luminance of the light source and the function are configured such that the luminance of the light source increases with increasing values of the maximum pixel luminance for at least a subset of the plurality of distribution factors.

5. The method of claim 1, wherein the applying comprises applying the selected distribution factor as a power of a fraction of the maximum pixel luminance.

6. The method of claim 1, wherein the applying comprises applying the selected distribution factor as a power of Lr/Lp, wherein Lr is the maximum pixel luminance in said region of the light modulation device and wherein Lp is a maximum pixel luminance of all regions in the light modulation device.

7. The method of claim 5, wherein the applying comprises applying the distribution factor as:

8. The method of claim 1, wherein a majority of distribution factor variances in said function occur only for a subrange of pixel luminances displayable by the light source.

9. The method of claim 8, wherein a substantial majority of said pixel luminances displayable by the light source are outside of said subrange.

10. The method of claim 9, wherein said substantial majority of said pixel luminances is at least about 98% of said pixel luminances displayable by the light source.

11. A system for displaying image information comprising:

a light modulation device including a pixel region;

an illumination device including a light source that is configured to illuminate the pixel region of the light modulation device; and

a control circuit configured to

determine, from the image information, a maximum pixel luminance in the pixel region of the light modulation device,

select a distribution factor based on a predetermined distribution factor function that is configured to select a given distribution factor for a plurality of pixel luminances below a predetermined maximum pixel luminance and is configured to select which one of a plurality of distribution factors larger than the given distribution factor corresponds to the maximum pixel luminance when the maximum pixel luminance is above the predetermined maximum pixel luminance,

calculate a luminance of the light source by applying the selected distribution factor to the maximum pixel luminance and calculate a transmission of the light modulation device for a pixel corresponding to the maximum pixel luminance, and

configure the light source of the illumination device to output said luminance of the light source and configure the light modulation device to implement the calculated transmission at the pixel such that the maximum pixel luminance is displayed at the pixel.

12. The system of claim 11, wherein the light source is a first light source, wherein the pixel region of the light modulation device is a first region, wherein the maximum pixel luminance is a first maximum pixel luminance, wherein the luminance of the light source is a first light source luminance and wherein the control circuit is further configured to;

select a second distribution factor that corresponds to a second maximum pixel luminance in a second region of the light modulation device based on the predetermined distribution factor function, wherein the second distribution factor is different from the first distribution factor;

calculate a second light source luminance of a second light source of the illumination system that is configured to illuminate the second region by applying the selected second distribution factor to the second maximum pixel luminance and calculate a second transmission of the light modulation device for an other pixel corresponding to the second maximum pixel luminance, and

configure the second light source of the illumination device to output said second light source luminance of the second light source and configure the light modulation device to implement the calculated second transmission at the other pixel such that the second maximum pixel luminance is displayed at the second pixel.

13. The system of claim 11, wherein the applying the selected distribution factor to the maximum pixel luminance comprises scaling a contribution of the maximum pixel luminance to the luminance of the light source with the selected distribution factor.

14. The system of claim 11, wherein the calculation of the luminance of the light source and the function are configured such that the luminance of the light source increases with increasing values of the maximum pixel luminance for at least a subset of the plurality of distribution factors.

15. The system of claim 11, wherein the applying comprises applying the selected distribution factor as a power of a fraction of the maximum pixel luminance.

16. The system of claim 11, wherein the applying comprises applying the selected distribution factor as a power of Lr/Lp, wherein Lr is the maximum pixel luminance in said region of the light modulation device and wherein Lp is a maximum pixel luminance of all regions in the light modulation device.

17. The system of claim 11, wherein a majority of distribution factor variances in said function occur only for a subrange of pixel luminances displayable by the light source.

18. The system of claim 17, wherein a substantial majority of said pixel luminances displayable by the light source are outside of said subrange.

19. The system of claim 18, wherein said substantial majority of said pixel luminances is at least about 98% of said pixel luminances displayable by the light source.

20. A method for displaying image information in a display system comprising:

determining, from the image information, a maximum pixel luminance in a region of a light modulation device;

selecting a distribution factor, which corresponds to the maximum pixel luminance, based on a predetermined distribution factor function that associates a plurality of distribution factors with a plurality of pixel luminances;

calculating a luminance of a light source of an illumination device configured to illuminate the region of the light modulation device by applying the selected distribution factor to the maximum pixel luminance and calculating a transmission of the light modulation device for a pixel corresponding to the maximum pixel luminance, wherein the applying comprises applying the selected distribution factor as a power of a fraction of the maximum pixel luminance; and

displaying the maximum pixel luminance at the pixel by configuring the light source of the illumination device to output said luminance of the light source and by configuring the light modulation device to implement the calculated transmission at the pixel.

21. The method of claim 20, wherein the applying comprises applying the selected distribution factor as the power of the fraction corresponding to Lr/Lp, wherein Lr is the maximum pixel luminance in said region of the light modulation device and wherein Lp is a maximum pixel luminance of all regions in the light modulation device.

22. The method of claim 20, wherein the applying comprises applying the selected distribution factor as the power of the fraction corresponding to

23. A method for displaying image information in a display system comprising:

determining, from the image information, a maximum pixel luminance in a region of a light modulation device, wherein a light source of an illumination device is configured to illuminate the region of the light modulation device;

selecting a distribution factor, which corresponds to the maximum pixel luminance, based on a predetermined distribution factor function that associates a plurality of distribution factors with a plurality of pixel luminances, wherein a majority of distribution factor variances in said function occur only for a subrange of pixel luminances displayable by the light source;

calculating a luminance of the light source by applying the selected distribution factor to the maximum pixel luminance and calculating a transmission of the light modulation device for a pixel corresponding to the maximum pixel luminance; and

displaying the maximum pixel luminance at the pixel by configuring the light source of the illumination device to output said luminance of the light source and by configuring the light modulation device to implement the calculated transmission at the pixel.

24. The method of claim 23, wherein a substantial majority of said pixel luminances displayable by the light source are outside of said subrange.

25. The method of claim 24, wherein said substantial majority of said pixel luminances is at least about 98% of said pixel luminances displayable by the light source.

26. A system for displaying image information comprising:

a light modulation device including a pixel region;

an illumination device including a light source that is configured to illuminate the pixel region of the light modulation device; and

a control circuit configured to

determine, from the image information, a maximum pixel luminance in the pixel region of the light modulation device,

select a distribution factor, which corresponds to the maximum pixel luminance, based on a predetermined distribution factor function that associates a plurality of distribution factors with a plurality of pixel luminances,

calculate a luminance of the light source by applying the selected distribution factor to the maximum pixel luminance and calculate a transmission of the light modulation device for a pixel corresponding to the maximum pixel luminance, wherein the applying comprises applying the selected distribution factor as a power of a fraction of the maximum pixel luminance, and

configure the light source of the illumination device to output said luminance of the light source and configure the light modulation device to implement the calculated transmission at the pixel such that the maximum pixel luminance is displayed at the pixel.

27. The system of claim 26, wherein the applying comprises applying the selected distribution factor as the power of the fraction corresponding to Lr/Lp, wherein Lr is the maximum pixel luminance in said region of the light modulation device and wherein Lp is a maximum pixel luminance of all regions in the light modulation device.

28. The system of claim 26, wherein the applying comprises applying the selected distribution factor as the power of the fraction corresponding to

29. A system for displaying image information comprising:

a light modulation device including a pixel region;

an illumination device including a light source that is configured to illuminate the pixel region of the light modulation device; and

a control circuit configured to

determine, from the image information, a maximum pixel luminance in the pixel region of the light modulation device,

select a distribution factor, which corresponds to the maximum pixel luminance, based on a predetermined distribution factor function that associates a plurality of distribution factors with a plurality of pixel luminances, wherein a majority of distribution factor variances in said function occur only for a subrange of pixel luminances displayable by the light source,

calculate a luminance of the light source by applying the selected distribution factor to the maximum pixel luminance and calculate a transmission of the light modulation device for a pixel corresponding to the maximum pixel luminance, and

configure the light source of the illumination device to output said luminance of the light source and configure the light modulation device to implement the calculated transmission at the pixel such that the maximum pixel luminance is displayed at the pixel.

30. The system of claim 29, wherein a substantial majority of said pixel luminances displayable by the light source are outside of said subrange.

31. The system of claim 30, wherein said substantial majority of said pixel luminances is at least about 98% of said pixel luminances displayable by the light source.