Projection displays

• US 9,412,337 B2
• Filed: 02/07/2014
• Issued: 08/09/2016
• 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:
  US14/175,046
• Publication Number:
  US 20140152713A1
• Time in Patent Office: 914 Days
• US Class Current: 1/1
• 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 display comprising:

a projector arranged to project light which has been spatially modulated according to image data onto a screen comprising a diffuser, the projector comprising separate light sources for each of a plurality of colors;

a monochrome light modulator arranged in a path of the light projected by the projector;

a control system configured to adjust luminance of the light at points on the diffuser by adjusting the modulation of the light by the projector and the modulation of the light by the monochrome light modulator.

2. The display according to claim 1 wherein the projector comprises a digital video projector.

3. The display according to claim 1 wherein the projector is higher in resolution than the monochrome spatial light modulator.

4. The display according to claim 1 wherein the projector comprises a deformable mirror device.

5. The display according to claim 1 wherein the monochrome spatial light modulator comprises a number of addressable elements which can be individually controlled to affect the luminance of corresponding areas of the screen.

6. The display according to claim 1 wherein the monochrome spatial light modulator comprises an array of elements having variable retro-reflection properties.

7. The display according to claim 6 wherein the elements of the monochrome spatial light modulator are prismatic.

8. The display according to claim 1 wherein the monochrome spatial light modulator comprises an array of electrophoretic display elements.

9. The display according to claim 1 wherein the monochrome spatial light modulator has fewer controllable elements than the projector.

10. The display according to claim 1 wherein the monochrome spatial light modulator has a lower resolution than the projector.

11. The display according to claim 10 wherein the control system is configured to determine a value for each pixel of the monochrome spatial light modulator and adjust the signals which control the projector to reduce artefacts which result from the fact that each pixel of the monochrome spatial light modulator is common to a plurality of pixels of the projector.

12. The display according to claim 10 wherein the control system is configured to set the pixels of the monochrome spatial light modulator to provide an approximation of the desired image.

13. The display according to claim 12 wherein the controller is configured to determine an average or weighted average of desired luminance values specified by the image data for image areas corresponding to each pixel of the monochrome spatial light modulator.

14. The display according to claim 1 wherein the screen comprises a lens element which functions to direct light preferentially toward the eyes of viewers.

15. The display according to claim 14 wherein the lens element comprises a Fresnel lens.

16. The display according to claim 14 wherein the lens element comprises a holographic lens.

17. The display according to claim 1 wherein the display is capable of displaying a luminance of 10⁵ cd/m².

18. The display according to claim 1 wherein the projector has over 1000 pixels in each direction.

19. The display according to claim 1 wherein the monochrome spatial light modulator has the same number of addressable elements as the projector.

20. The display according to claim 1 wherein a ratio of a luminance of points on the screen for which corresponding controllable elements of each of the projector and monochrome spatial light modulator are both set to provide a maximum illumination and a luminance points on the screen for which corresponding controllable elements of each of the projector and monochrome spatial light modulators are both set to provide a minimum illumination have a ratio exceeding 1000:

1.