Edge lit locally dimmed display

• US 8,172,401 B2
• Filed: 04/29/2011
• Issued: 05/08/2012
• Est. Priority Date: 02/27/2001
• Status: Expired due to Term

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Whitehead, Lorne A., WARD, Gregory John, Stuerzlinger, Wolfgang, Seetzen, Helge
• Primary Examiner(s): Dowling, William C
• Application Number:
  US13/097,823
• Publication Number:
  US 20110216387A1
• Time in Patent Office: 375 Days
• Field of Search: 353/30, 353/31, 353/79, 353/85, 353/121, 348/771, 349/5, 349/7, 315/307, 359443-461
• 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

An edge lit locally dimmed display has a spatial light modulator illuminated by a light source. The light source is positioned at an edge and behind the spatial light modulator. The spatial light modulator is illuminated with a low resolution version of a desired image. The illumination may comprise a series of lighting elements that vary smoothly from one element to another at the spatial light modulator.

Claims

1. An edge lit locally dimmed display, comprising:

a spatial light modulator;

a light source configured to cause an illumination of the spatial light modulator;

wherein;

the light source is at an edge and behind a viewing side of the spatial light modulator;

the illumination is based on image data defining a desired image, and

the illumination comprises a series of lighting elements that vary smoothly from one element to another at the spatial light modulator.

2. The edge lit locally dimmed display according to claim 1, wherein the series of lighting elements comprises lighting elements having a spread function of 0.3d2 to 3d2 where d2 is a spacing between the lighting elements.

3. The edge lit locally dimmed display according to claim 1, wherein the series of lighting elements comprises lighting elements having a spread function comprising a full width at half maximum of 0.3d2 to 3d2 where d2 is a spacing between the lighting elements.

4. The edge lit locally dimmed display according to claim 1, wherein the series of lighting elements comprises lighting elements having a spread function comprising a convolution of a rectangular function having a full width at half maximum of 0.3d2 to 3d2 where d2 is a center-to-center spacing between the lighting elements.

5. The edge lit locally dimmed display according to claim 1, wherein the illumination comprises a series of lighting elements, and wherein the illumination comprises an illumination pattern configured to reduce artifacts due to a disparity in resolution between the lighting elements and the spatial light modulator.

6. The edge lit locally dimmed display according to claim 1, wherein the illumination is provided at least in part by reflection from the light source to the spatial light modulator.

7. The edge lit locally dimmed display according to claim 1, wherein the illumination is provided by at least redirecting light from the light source to the spatial light modulator.

8. The edge lit locally dimmed display according to claim 7, wherein the redirecting of light from the light source comprises reflection and diffusion.

9. The edge lit locally dimmed display according to claim 1, wherein the light source projects light in a direction substantially parallel to a plane of the spatial light modulator and is redirected to a direction that is substantially perpendicular to the plane of the spatial light modulator.

10. The edge lit locally dimmed display according to claim 1, wherein:

the light source projects light in a direction substantially parallel to a plane of the spatial light modulator and is redirected to a direction that is substantially perpendicular to the plane of the spatial light modulator;

the illumination comprises an illumination pattern configured to reduce artifacts due to a disparity in resolution between the lighting elements and the spatial light modulator;

the illumination comprises a series of lighting elements having a spread function of 0.3d2 to 3d2 where d2 is a spacing between the lighting elements at their origin.

11. The edge lit locally dimmed display according to claim 1, wherein the spatial light modulator is configured to cause a resulting image on the spatial light modulator to approach the desired image by setting the spatial light modulator based on the approximation of the desired image which comprises a known intensity of light incident on the spatial light modulator and includes light from the lighting elements spreading into light of adjacent lighting elements.

12. The edge lit locally dimmed display according to claim 1, wherein the illumination comprises luminance values of a known intensity of light incident on the spatial light modulator caused in part by spreading of light from areas of the illumination into adjacent areas of the illumination according to said spread function, and, the spatial light modulator is configured to cause the illumination to approach a desired image based at least in part on the luminance values of known intensity.

13. The edge lit locally dimmed display according to claim 1, wherein the spatial light modulator is configured to further modulate the illumination incident on the spatial light modulator to approach the desired image by setting modulation values of the spatial light modulator in consideration of the illumination that includes spreading of light from the lighting elements into light of adjacent lighting elements and image data of the desired image.

14. The edge lit locally dimmed display according to claim 1, wherein the illumination on the spatial light modulator includes spreading of light from each of the lighting elements into light from adjacent lighting elements, the display further comprising a controller configured to set the spatial light modulator to produce a resulting image that approaches the desired image in consideration of the illumination and spread light.

15. The edge lit locally dimmed display according to claim 1, further comprising a controller configured to set the spatial light modulator in consideration of known intensity values of light incident on the spatial light modulator to produce a resulting image that approaches the desired image.

16. The edge lit locally dimmed display according to claim 15, wherein the known intensity values of light incident on the spatial light modulator include spreading of light from the lighting elements into light of adjacent lighting elements according to said spread function.

17. The edge lit locally dimmed display according to claim 1, wherein the illumination is provided on a plane adjacent to a non-viewing side of the spatial light modulator.

18. The edge lit locally dimmed display according to claim 1, wherein the illumination is provided on a plane adjacent to a non-viewing side of the spatial light modulator and directed toward the spatial light modulator.

19. The edge lit locally dimmed display according to claim 1, wherein the illumination is formed on a plane adjacent the spatial light modulator and projected onto the spatial light modulator.

20. The edge lit locally dimmed display according to claim 1, wherein the illumination is provided on a plane behind the spatial light modulator and in a position to project onto the spatial light modulator.

21. The edge lit locally dimmed display according to claim 1, wherein the elements of the illumination are formed behind the spatial light modulator and comprise light redirected from the light source to the spatial light modulator.

22. The edge lit locally dimmed display according to claim 21, wherein the elements of the illumination are formed in a plane behind the spatial light modulator and then redirected to the spatial light modulator.

23. The edge lit locally dimmed display according to claim 21, wherein the redirected light comprises reflected light.

24. The edge lit locally dimmed display according to claim 21, wherein the redirected light comprises reflected and diffused light.

25. The edge lit locally dimmed display according to claim 22, wherein the elements of the illumination have spread function that causes the illumination to vary smoothly from one element to the next at the spatial light modulator.

26. The edge lit locally dimmed display according to claim 25, the light source projects light in a direction substantially parallel to a plane of the spatial light modulator and is redirected to a direction that is substantially perpendicular to the plane of the spatial light modulator.

27. The edge lit locally dimmed display according to claim 26, wherein the lighting elements having a spread function of 0.3d2 to 3d2 where d2 is a spacing between lighting elements.

28. A locally dimmed display method, comprising the steps of:

energizing a lighting device;

redirecting light from the energized lighting device onto a spatial light modulator; and

modulating the reflected light to produce a desired image;

wherein;

the redirected light is based on image data defining a desired image;

the lighting device is located at an edge and behind the spatial light modulator; and

the redirected light comprises a series of lighting elements that vary smoothly from one element to another at the spatial light modulator.

29. The locally dimmed display method according to claim 28, wherein the series of lighting elements comprises lighting elements having a spread function of 0.3d2 to 3d2 where d2 is a spacing between the lighting elements at their origin.

30. The locally dimmed display method according to claim 28, wherein the series of lighting elements comprises lighting elements having a spread function comprising a full width at half maximum of 0.3d2 to 3d2 where d2 is a spacing between the lighting elements at their origin.

31. The locally dimmed display method according to claim 28, wherein the series of lighting elements comprises lighting elements having a spread function comprising a convolution of a rectangular function having a full width at half maximum of 0.3d2 to 3d2 where d2 is a center-to-center spacing between the lighting elements at their origin.

32. The locally dimmed display method according to claim 28, wherein the reflected light comprises an illumination pattern configured to reduce artifacts due to a disparity in resolution between the lighting elements and the spatial light modulator.

33. The locally dimmed display method according to claim 28, wherein the light source projects light in a direction substantially parallel to a plane of the spatial light modulator and is reflected to a direction that is substantially perpendicular to the plane of the spatial light modulator.

34. The locally dimmed display method according to claim 28, wherein:

the light source projects light in a direction substantially parallel to a plane of the spatial light modulator and is reflected to a direction that is substantially perpendicular to the plane of the spatial light modulator;

the reflected light comprises an illumination pattern configured to reduce artifacts due to a disparity in resolution between the lighting elements and the spatial light modulator;

the reflected light comprises a series of lighting elements having a spread function of 0.3d2 to 3d2 where d2 is a spacing between the lighting elements at their origin.

35. The locally dimmed display method according to claim 28, wherein the redirected light originates from an edge of the display.

36. The locally dimmed display method according to claim 28, wherein the display comprises an edge lit locally dimmed display.

37. The locally dimmed display method according to claim 28, wherein the lighting device projects light in a direction substantially parallel to a plane of the spatial light modulator and is redirected to a direction that is substantially perpendicular to the plane of the spatial light modulator.

38. The locally dimmed display method according to claim 37, wherein the step of redirecting light comprises reflection and diffusion.

39. The locally dimmed display method according to claim 28, wherein the step of modulating comprises a spatial light modulator configured to cause a resulting image on the spatial light modulator to approach the desired image by setting the spatial light modulator based on the approximation of the desired image which comprises a known intensity of light incident on the spatial light modulator and includes light from the lighting elements spreading into light of adjacent lighting elements.

40. The locally dimmed display method according to claim 28, wherein the redirected light comprises luminance values of a known intensity of light incident on the spatial light modulator caused in part by spreading of light from areas of the illumination into adjacent areas of the illumination according to said spread function, and, the spatial light modulator is configured to cause the illumination to approach a desired image based at least in part on the luminance values of known intensity.

41. The locally dimmed display method according to claim 28, wherein the spatial light modulator is configured to further modulate the redirected light incident on the spatial light modulator to approach the desired image by setting modulation values of the spatial light modulator in consideration of the illumination that includes spreading of light from the lighting elements into light of adjacent lighting elements and image data of the desired image.

42. The locally dimmed display method according to claim 28, wherein the redirected light on the spatial light modulator includes spreading of light from each of the lighting elements into light from adjacent lighting elements, the display further comprising a controller configured to set the spatial light modulator to produce a resulting image that approaches the desired image in consideration of the redirected spread light.

43. The locally dimmed display method according to claim 28, further comprising a controller configured to set the spatial light modulator in consideration of known intensity values of light incident on the spatial light modulator to produce a resulting image that approaches the desired image.

44. The locally dimmed display method according to claim 43, wherein the known intensity values of light incident on the spatial light modulator include spreading of light from the lighting elements into light of adjacent lighting elements according to said spread function.