Projection displays

• US 9,804,487 B2
• Filed: 07/07/2016
• Issued: 10/31/2017
• 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:
  US15/204,735
• Publication Number:
  US 20160320694A1
• Time in Patent Office: 481 Days
• 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 screen;

a color projector operative to project spatially modulated light of each of a plurality of colors onto the screen;

the screen comprising an array of elements having variable optical properties; and

a controller connected to receive image data defining an image to be displayed and to control the optical properties of the elements of the screen based on the image data to provide an image to a viewing area having an increased dynamic range in comparison to a dynamic range of the spatially modulated light projected onto the screen by the projector.

2. A display area according to claim 1 wherein the elements of the screen provide variable light absorption properties controlled by the controller.

3. A display according to claim 2 wherein the elements of the screen are LCD elements.

4. A display according to claim 3 wherein the screen comprises a reflective backing and the LCD elements are in front of the reflective backing.

5. A display according to claim 1 wherein the elements of the screen comprise elements having variable retro-reflection properties.

6. A display according to claim 5 wherein the elements are prismatic.

7. A display according to claim 1 wherein the elements of the screen comprise electrophoretic elements.

8. A display according to claim 1 wherein the screen comprises a lens element arranged to direct light from the screen preferentially toward the viewing area.

9. A display according to claim 8 wherein the lens element comprises a Fresnel lens.

10. A display according to claim 8 wherein the lens element comprises a holographic lens.

11. A display according to claim 2 wherein the controller comprises a computer connected to process the image data and to generate driving signals for the projector and the elements of the screen on the fly based on the image data.

12. A display according to claim 2 wherein the controller supplies different data to drive the projector and the elements of the screen.

13. A display according to claim 1 wherein the projector comprises separate light sources for different colors.

14. A display according to claim 1 wherein the screen comprises a diffuser operative to scatter outgoing light through a range of directions.

15. A display according to claim 14 wherein the diffuser scatters light to different extents in horizontal and vertical directions.

16. A display according to claim 1 wherein the controller controls the elements of the screen based on a known intensity of light incident from the projector.

17. A display according to claim 2 wherein the projector and the elements of the screen provide different resolutions and the controller is operable to determine a value for each pixel of a lower-resolution one of the projector and the elements of the screen and to adjust the signals which control the higher-resolution one of the projector and the screen elements to reduce artefacts which result from the fact that each pixel of the lower-resolution one of the projector and the screen elements is common to a plurality of pixels of the higher-resolution one of the projector and the screen elements.

18. A display according to claim 17 wherein the controller is configured to set the lower-resolution one of the projector and the screen elements to provide an approximation of the desired image specified by the image data.

19. A display according to claim 18 wherein the controller is configured to set the pixels of the lower-resolution one of the projector and the screen elements to values determined based on an average or weighted average of desired luminance values for image areas corresponding to the pixels of the lower-resolution one of the projector and the screen elements.