Projection displays

• US 8,684,533 B2
• Filed: 02/03/2013
• Issued: 04/01/2014
• 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:
  US13/757,822
• Publication Number:
  US 20130148037A1
• Time in Patent Office: 422 Days
• Field of Search: 353/30, 353/31, 353/79, 353/85, 353/94, 353/121, 349/5, 349/7, 349/8, 349/9, 348/758
• 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 locally dimmed display has a spatial light modulator illuminated by a light source. 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. A digital projector, comprising:

an input configured to receive an image signal representative of a desired image;

a spatial light modulator;

a modulated light source configured to illuminate the spatial light modulator;

a controller configured to energize the modulated light source and the spatial light modulator based on the image signal;

wherein the controller is further configured to energize the light source according to a luminance of the desired image, and energize pixels of the spatial light modulator according to an amount of smoothly varying luminance illuminating the pixels of the spatial light modulator and a corresponding amount of luminance in the desired image.

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

3. The digital projector according to claim 1, wherein the modulated light source comprises laser light sources.

4. The digital projector according to claim 1, wherein the modulated light source comprises lasers.

5. The digital projector according to claim 1, wherein the modulated light source comprises one or more narrow-band light sources.

6. The digital projector according to claim 1, wherein the modulated light source is configured to produce modulated pixels of light, the digital projector arranged such that adjacent modulated pixels of light from the modulated light source spread into each other at the spatial light modulator.

7. The digital projector according to claim 6, wherein the spreading of the adjacent modulated pixels of light causes a smoothly varying pattern of light to illuminate the spatial light modulator.

8. The digital projector according to claim 6, wherein the spreading of the adjacent modulated pixels of light is characterized by a light spread function having a full width at half maximum of from 0.3 d2 to 3d2 where d2 is a spacing between the adjacent pixels.

9. The digital projector according to claim 1, wherein the modulated light source is configured to separately modulate light directed toward a plurality of portions of the spatial light modulator and the light directed at the each of the plurality of portions of the spatial light modulator spreads to illuminate adjacent ones of the portions.

10. The digital projector according to claim 1, further comprising at least one additional light modulator disposed in a light path of the projector.

11. The digital projector according to claim 7, wherein the modulated light source comprises laser light sources.

12. The digital projector according to claim 6, wherein the modulated light source comprises lasers.

13. The digital projector according to claim 6, wherein the modulated light source comprises one or more narrow-band light sources.

14. The digital projector according to claim 8, wherein the modulated light source comprises laser light sources.

15. The digital projector according to claim 7, further comprising a diffuser configured to contribute to the smoothly varying pattern of light.

16. The digital projector according to claim 1, wherein the modulated light source comprises a plurality of light sources and a plurality of light modulators each arranged to modulate a beam of light.

17. The digital projector according to claim 1, wherein the spatial light modulator comprises red, green, and blue light modulators.

18. A digital video projector, comprising:

a spatial light modulator comprising a plurality of modulation stages and an optical system configured to relay light from an upstream modulation stage to a downstream modulation stage;

a light source comprising a plurality of light sources;

a controller configured to energize the light source according to image data and energize the spatial light modulator according to the image data and amount of light illuminating pixels of the spatial light modulator.

19. The digital video projector according to claim 18, wherein the upstream modulation stage comprises optical elements configured to manage the relay of light to the downstream modulation stage in a manner that causes portions of light modulated by elements of the upstream modulation stage to spread into each other and vary smoothly across the downstream modulation stage.

20. The digital video projector according to claim 19, wherein the portions of light comprise a spread function having a full width at half maximum of from 0.3 d2 to 3d2 where d2 is a spacing between modulation elements of the upstream modulation stage.

21. The digital video projector according to claim 20, wherein the light source comprises lasers.

22. The digital video projector according to claim 21, wherein the spatial light modulator comprises a Digital Mirror Device (DMD).

23. The digital video projector according to claim 22, further comprising an additional modulator operating in conjunction with the DMD modulator to further modulate light from the light sources.

24. The digital video projector according to claim 22, further comprising an additional DMD modulator operating in conjunction with the DMD modulator to further modulate light from the light sources.

25. The digital video projector according to claim 18, wherein the light source comprises one or more narrow-band light sources.

26. The digital video projector according to claim 18, wherein the plurality of light sources comprises at least one red light source, one green light source, and one blue light source.

27. A laser projector, comprising:

a plurality of laser light sources configured to illuminate a plurality of downstream modulators;

a controller configured to control energization of the laser light sources according to image data;

the controller further configured to control energization of the plurality of downstream modulators according to image data and a luminance of light incident on the downstream modulator being energized; and

wherein at one or more of the downstream modulators, light modulated by elements of an upstream modulator spreads into light modulated by adjacent elements of the upstream modulator such that the light incident on the one or more of the downstream modulators varies smoothly.

28. The laser projector according to claim 27, wherein the smoothly varying light incident on at least one of the downstream modulators comprises a spread function between light modulated by adjacent elements of the upstream modulator comprising a full width at half maximum of 0.3 d2 to 3 d2 where d2 is a spacing between adjacent elements of the upstream modulator.

29. The laser projector according to claim 28, wherein the plurality of downstream modulators comprises a plurality of reflection-type spatial light modulators.

30. The laser projector according to claim 29, wherein the plurality of reflection-type spatial light modulators comprises a dual DMD device.

31. The laser projector according to claim 29, comprising an enlarging optical system downstream from the spatial light modulators and configured to project an image modulated by the spatial light modulators.

32. The laser projector according to claim 31, further comprising a front-projection screen onto which the enlarging optical system is configured to project the modulated image.

33. The laser projector according to claim 31, further comprising a screen configured to receive and display the projected image in a rear projection configuration.