HIGH DYNAMIC RANGE DISPLAY DEVICES HAVING COLOR LIGHT SOURCES

• US 20090180078A1
• Filed: 03/24/2009
• Published: 07/16/2009
• Est. Priority Date: 02/27/2001
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Seetzen, Helge, Stuerzlinger, Wolfgang, Ward, Greg, Whitehead, Lorne
• Granted Patent: US 7,801,426 B2
• Time in Patent Office: Days
• US Class Current: 353/30
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
• CPC Class Codes: G03B 21/14 Details
• CPC Class Codes: G03B 21/2053 Intensity control of illuminating light controlled by video signal processing H04N5/74 or H04N9/31
• CPC Class Codes: G03B 21/26 Projecting separately subsidiary matter simultaneously with main image
• CPC Class Codes: G03B 21/56 Projection screens
• CPC Class Codes: G03B 21/567 for colour projection G03B21/58, G03B21/60 take precedence
• CPC Class Codes: G03B 21/60 characterised by the nature of the surface
• CPC Class Codes: G03B 21/625 Lenticular translucent screens
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• 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 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 5/10 Intensity circuits
• CPC Class Codes: H04N 5/7416 : involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• CPC Class Codes: H04N 9/31 : Projection devices for colour picture display , e.g. using electronic spatial light modulators [ESLM]
• CPC Class Codes: H04N 9/3126 : for spatial light modulators in series
• CPC Class Codes: H04N 9/3138 : using arrays of modulated light sources electroluminescent display devices G09G3/30
• CPC Class Codes: H04N 9/3188 : Scale or resolution adjustment scaling in general G06T3/40; resolution modifying circuits for displays in general G09G5/391

Abstract

A display has a screen which incorporates a light modulator. The screen may be a front projection screen or a rear-projection screen. Elements of the light modulator may be controlled to adjust the intensity of light emanating from corresponding areas on the screen. The display may provide a high dynamic range.

Claims

1. A device, comprising:

a modulated light source;

a modulator having a higher resolution than a resolution of the modulated light source;

an optical arrangement comprising an alignment of the modulated light source and the higher resolution modulator that causes pixels of the modulated light source to be projected onto the higher resolution modulator;

wherein;

the modulated light source is configured to cause the pixels of the modulated light source to form a low resolution version of an image;

the pixels of the modulated light source projected onto the higher resolution modulator each correspond to a plurality of pixels of the higher resolution modulator; and

the pixels of the modulated light source are diffuse and spread into adjacent pixels so as to cause a smoothly varying light intensity from one pixel of the modulated light source to other pixels of the modulated light source.

2. The device according to claim 1, wherein the modulated light source comprises red, green, and blue light sources.

3. The device according to claim 1, wherein the pixels of the modulated light source comprise an intensity profile comprising a full width at half maximum in the range of 0.3d2 to 3d2 where d2 is a center-to-center inter-pixel spacing of the modulated light source.

4. The device according to claim 3, wherein the intensity profile further comprises a Gaussian spread function having a width approximately equal to d2.

5. The device according to claim 3, wherein the intensity profile further comprises an approximation of a Gaussian spread function convolved with a rectangular profile having a width equal to an active width of the pixel.

6. The device according to claim 1, wherein the higher resolution modulator is configured to be operable in response to differences between the low resolution version of the image and the image determined by dividing desired luminance values by a known intensity of light incident from the modulated light source on the corresponding pixels of the higher resolution light modulator.

7. The device according to claim 1, wherein the higher resolution modulator is configured to be operable in a manner that reduces artifacts.

8. The device according to claim 1, configured so that artifacts caused by pixels of the modulated light source corresponding to a plurality of pixels of the higher resolution modulator are reduced by a manner in which the higher resolution modulator is controlled.

9. The device according to claim 1, wherein the modulated light source comprises at least one light source and at least one light modulator.

10. The device according to claim 1, wherein the modulated light source comprises a plurality of light sources and a mechanism for modulating the plurality of light sources.

11. The device according to claim 1, wherein the modulated light source comprises a spatially modulated light source.

12. The device according to claim 1, wherein the modulated light source comprises a plurality of different color light sources and a mechanism for causing the plurality of different color light sources to be spatially modulated.

13. The device according to claim 1, wherein the high resolution modulator comprises a color modulator.

14. The device according to claim 1, wherein the high resolution modulator comprises an LCD screen.

15. The device according to claim 1, wherein the modulated light source comprises individual red, green, and blue lights.

16. The device according to claim 1, wherein the modulated light source comprises red, green, and blue (RGB) lights and individual RGB modulators.

17. The device according to claim 1, wherein the modulated light source comprises a first light comprising a red light emission, a second light comprising a green light emission, and a third light comprising a blue light emission.

18. The device according to claim 1, wherein the modulated light source comprises a first color light, a second color light, and a third color light.

19. The device according to claim 1, wherein the modulated light source comprises a light comprising a red light emission.

20. The device according to claim 1, wherein the modulated light source comprises a light comprising a blue light emission.

21. The device according to claim 1, wherein the device comprises a high dynamic range display having a contrast ratio greater than 1000:

1.

22. A display, comprising:

a modulated light source comprising red, green, and blue (RGB) lights;

a modulator having relatively high resolution compared to a resolution of the modulated light source;

an optical arrangement comprising an alignment of the modulated light source and the high resolution modulator that causes pixels of the modulated light source to be projected onto the high resolution modulator;

wherein;

pixels of the modulated light source comprises an intensity profile comprising a full width at half maximum in the range of 0.3d2 to 3d2 where d2 is a center-to-center inter-pixel spacing of the modulated light source;

the intensity profile further comprising a Gaussian spread function having a width approximately equal to d2 and a Gaussian spread function convolved with a rectangular profile having a width equal to an active width of the pixel;

the modulated light source is configured to cause the pixels of the modulated light source to form a low resolution version of an image;

pixels of the modulated light source projected onto the high resolution modulator each correspond to a plurality of pixels of the high resolution modulator;

pixels of the modulated light source are diffuse and spread into adjacent pixels so as to cause a smoothly varying light intensity from one pixel of the modulated light source to other pixels of the modulated light source;

artifacts caused by pixels of the modulated light source corresponding to a plurality of pixels of the higher-resolution spatial light modulator are reduced by a manner in which the high resolution modulator is energized;

the high resolution modulator is configured to be controlled differences between the low resolution version of the image and the image obtained by dividing desired luminance values by a known intensity of light incident from the modulated light source on the corresponding pixels of the higher-resolution light modulator; and

the display is a high dynamic range display having a contrast ratio of greater than 1000 to one.

23. A display, comprising:

an LCD panel;

a locally dimmed RGB backlight; and

a controller configured to produce a local dimming signal configured to control the locally dimmed RGB backlight with an approximation of a desired image;

wherein;

each pixel of the locally dimmed backlight corresponding to and illuminating a plurality of pixels of the LCD panel;

the locally dimmed RGB backlight comprises pixels that spread into each other so as to produce a diffuse and smoothly varying low resolution version of the desired image on a non-viewing side of the LCD panel; and

the local dimming signal is further configured to reduce artifacts caused by pixels of the locally dimmed RGB backlight corresponding to a plurality of pixels of the LCD panel.

24. The display according to claim 23, wherein the LCD panel is energized by differences between the approximation of the desired image and the desired image by dividing desired luminance values by a known intensity of light incident from the locally dimmed RGB backlight on the corresponding pixels of the LCD panel.

25. The display according to claim 24, wherein pixels of the locally dimmed RGB backlight comprise an intensity profile comprising a full width at half maximum in the range of 0.3d2 to 3d2 where d2 is a center-to-center inter-pixel spacing of the locally dimmed RGB backlight.

26. The display according to claim 25, wherein the display comprises a high dynamic range display having a contrast ratio of at least 1000:

1.

27. A display comprising:

a spatial light modulator;

a backlight arranged to illuminate the spatial light modulator, the backlight comprising a plurality of sources of spatially-modulated, colored light, each of the sources of spatially-modulated colored light comprising pixels operable to illuminate the backlight with light of a color corresponding to the source of spatially-modulated colored light wherein light output by the pixels spreads onto adjacent pixels so as to produce a smoothly varying light intensity;

a controller configured to set the pixels of the backlight to provide an approximation of a desired image and to set the pixels of the spatial light modulator to cause a resulting image to approach the desired image.

28. The display according to claim 27 wherein the controller is configured to determine differences between the approximation of the desired image and the desired image by dividing desired luminance values by an intensity of light incident from the backlight on the corresponding pixels of the spatial light modulator.

29. The display according to claim 28 wherein the controller is configured to adjust signals which control the spatial light modulator to reduce artefacts in the resulting image.

30. The display according to claim 27 wherein the sources of spatially-modulated, colored light comprise sources of red, green, and blue light.

31. The display according to claim 27, wherein the display comprises a high dynamic range display having a contrast ratio greater than 1000:

1.

32. The display according to claim 27, wherein the spatial light modulator comprises an LCD screen.

33. The display according to claim 27, wherein light output by the pixels of the backlight is characterized by an intensity profile comprising a full width at half maximum in the range of 0.3d2 to 3d2 where d2 is a center-to-center inter-pixel spacing of the pixels of the backlight.

34. The display according to claim 33, wherein the intensity profile comprises a Gaussian spread function having a full-width-at-half-maximum in the range of 0.3d2 to 3d2.

35. The display according to claim 33, wherein a maximum luminance of the resulting image is on the order of 10⁵ cd/m².

36. The display according to claim 27, wherein the spatial light modulator has a resolution higher than that of the spatial modulation of the backlight.