Wide Color Gamut Displays

• US 20080204479A1
• Filed: 12/24/2004
• Published: 08/28/2008
• Est. Priority Date: 12/23/2004
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Incorporated
• Inventors: Seetzen, Helge
• Granted Patent: US 8,164,602 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• 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 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/36 using liquid crystals

Abstract

A display has a modulator illuminated by a illuminator comprising an array of light sources. The array includes light sources of a plurality of colors. The light sources of different colors are individually controllable. Within each color, the light sources that illuminate different areas on the modulator are individually controllable. The display may provide a high dynamic range and a wide color gamut.

Claims

1. A display comprising:

an illuminator comprising an array of light sources, the light sources including light sources of a plurality of colors;

a modulator disposed to be illuminated by the illuminator, the modulator comprising a plurality of pixels, each having a plurality of elements;

an illuminator driver circuit, the illuminator driver circuit configured to independently control intensities of the light sources in each of a plurality of areas of the illuminator and, within each of the areas, independently control intensities of the light sources of each of the plurality of colors, wherein the light sources in each of the plurality of areas of the illuminator are arranged to illuminate a corresponding area of the modulator with light having a color and intensity controllable by the illuminator driver circuit; and

,

a modulator driver circuit connected to control modulation of the light from the illuminator by the pixel elements.

2. A display according to claim 1 wherein the modulator comprises a liquid crystal display panel.

3. A display according to claim 1 or 2 wherein the light sources comprise light-emitting diodes.

4. A display according to claim 1 wherein the illuminator includes first light sources that are capable of emitting light of a first color and second light sources that are capable of emitting light of a second color wherein individual ones of the first light sources are capable of providing greater light output than individual ones of the second light sources.

5. A display according to claim 4 wherein the first light sources are more widely spaced apart from one another in the array than the second light sources.

6. A display according to claim 5 wherein the first light sources have wider point spread functions than the second light sources.

7. A display according to claim 6 wherein a ratio of the spacing of the first light sources to the spacing of the second light sources is within 15% of a ratio of the width of the point spread function of the first light sources to the width of the point spread function of the second light sources.

8. A display according to claim 5 wherein, when operated at maximum light output, the light sources of each of the different colors illuminate the modulator with an average intensity that is within 15% of an average intensity of the light of each of the other colors.

9. A display according to claim 1 wherein the array includes a different number of discrete light sources of each of the plurality of colors.

10. A display according to claim 9 wherein a maximum light output of the light sources of one of the colors multiplied by the number of light sources of that color is substantially equal for each of the colors.

11. A display according to claim 1 wherein the elements of the modulator include elements having filters having a bandwidth of 150 nm or less.

12. A display according to claim 1 wherein the elements of the pixels of the modulator include elements corresponding to each of the plurality of colors wherein the elements each include a color filter that can pass light of the corresponding color but blocks light of other ones of the plurality of colors.

13. A display according to claim 12 wherein the color filters have bandwidths of 150 nm or less.

14. A display according to claim 12 wherein the elements of the pixels of the modulator include at least one broadband element, the broadband element capable of passing light of two or more of the plurality of colors.

15. A display according to claim 1 comprising a controller configured to control the modulator driver circuit based on both image data and a light pattern projected onto the modulator by the illuminator.

16. A display according to claim 15 wherein the controller comprises means for estimating a light pattern projected onto the modulator by the illuminator for each of the plurality of colors.

17. A display according to claim 16 wherein the controller comprises means for determining a modulator driving signal for each of the plurality of colors based, for each color, on the image data for the color and an estimated light pattern for the color.

18. Apparatus for displaying images at a viewing area, the apparatus comprising:

an array comprising a plurality of groups of individually-controllable light sources, the light sources of each group capable of emitting light of a corresponding one of a plurality of colors;

a modulator having an active area comprising a plurality of pixels, the active area arranged to be illuminated by the array, each pixel controllable to vary a proportion of light incident on the active area that is passed to the viewing area; and

,

a control circuit configured to drive each of the groups of the light sources according to a control signal to project a luminance pattern onto the active area of the modulator, the luminance pattern for each of the groups having a variation in intensity over the active area controlled by the control circuit.

19. A method for displaying images at a viewing area, the method comprising:

providing an array comprising a plurality of groups of individually-controllable light sources, the light sources of each group emitting light of a corresponding one of a plurality of colors;

driving the array in response to a control signal such that each of the groups projects a luminance pattern onto an active area of a modulator comprising a plurality of pixels, each luminance pattern having a variation in intensity with position on the active area determined by the control signal; and

,

controlling the pixels of the modulator to selectively allow light from the active area to pass to the viewing area.

20. A method according to claim 19 wherein each pixel of the modulator comprises a plurality of individually-controllable elements, the plurality of individually-controllable elements including basic elements that, for each of the plurality of colors, have a color filter that can pass light of the color but blocks light of other ones of the plurality of colors and wherein controlling the pixels of the modulator comprises controlling the basic elements of each pixel.

21. A method according to claim 20 wherein the individually-controllable elements include a broadband element that passes light of two or more colors, and the method comprises:

determining modulator values for the broadband elements, the modulator values controlling the transmission of light by the broadband elements, and,

determining modulator values for other ones of the elements based at least in part on the modulator values for the broadband elements.

22. A method according to claim 21 wherein the illuminator comprises light sources of an additional color not passed by any of the basic elements and wherein determining modulator values for the broadband elements comprises selecting modulator values to pass desired amounts of light of the additional color.

23. A method according to claim 21 wherein each pixel of the modulator comprises a plurality of elements, the elements for each pixel including at least basic elements corresponding to each of the plurality of colors, the method comprising:

generating illuminator values for each of the plurality of colors from image data defining an image to be displayed, the illuminator values for each color determining brightness of the light sources in the group of light sources of the color;

for each of the plurality of colors estimating a luminance pattern that would be produced on the modulator by driving the array according to the illuminator values;

for each of the plurality of colors, determining modulator values from the image data and the estimated luminance pattern for that color;

driving each of the groups of light sources in the array according to the corresponding illuminator values and driving the basic elements of the modulator according to the corresponding modulator values to reproduce the image.

24-25. -25. (canceled)