Edge lit LED based locally dimmed display

• US 8,446,351 B2
• Filed: 01/25/2012
• Issued: 05/21/2013
• Est. Priority Date: 03/13/2002
• Status: Expired due to Term

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Stuerzlinger, Wolfgang, Seetzen, Helge, Graham, Don, Whitehead, Lorne A., WARD, Gregory John
• Primary Examiner(s): Bolotin, Dmitriy
• Application Number:
  US13/358,311
• Publication Number:
  US 20120120131A1
• Time in Patent Office: 482 Days
• Field of Search: 345/3.1, 345/5, 345/84, 345/85, 345/87, 345/204, 345/214, 345629-641, 349/24, 349/25, 349/27, 349/29, 349/30, 349/149, 349/5, 349/7, 353/31, 353/79, 353/85, 353/121, 348/771, 315/307, 359443-461
• US Class Current: 345/87
• CPC Class Codes: G02F 1/133524 Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133613 characterized by the sequence of light sources
• 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: 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• 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 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2330/08 Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/34 by control of light from an independent source
• CPC Class Codes: G09G 3/3426 : the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3611 : Control of matrices with row and column drivers
• CPC Class Codes: H01J 63/06 : Lamps with luminescent screen excited by the ray or stream
• CPC Class Codes: H04N 9/3102 : using two-dimensional electronic spatial light modulators micromechanical modulators as such G02B26/0833; liquid crystal modulators as such G02F1/13
• CPC Class Codes: H04N 9/3126 : for spatial light modulators in series
• CPC Class Codes: H04N 9/3155 : for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406
• CPC Class Codes: H04N 9/3194 : including sensor feedback
• CPC Class Codes: H04N 9/3197 : using light modulating optical valves
• CPC Class Codes: H05B 45/20 : Controlling the colour of the light

Abstract

A display has a screen which incorporates a light modulator. The screen may be a front projection screen or a rear-projection screen. The screen is illuminated with light from a light source comprising an array of controllable light-emitters. The controllable-emitters and 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. An edge lit locally dimmed display, comprising:

a spatial light modulator;

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

wherein;

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

the illumination comprises a series of lighting elements having a spread function causing the illumination to vary smoothly at the spatial light modulator; and

the illumination comprises a low resolution version of a desired image.

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

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

8. 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.

9. The edge lit locally dimmed display according to claim 8, 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.

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 the light from the light source is redirected to a direction that is substantially perpendicular to the plane of the spatial light modulator.

11. The edge lit locally dimmed display according to claim 10, wherein the redirecting of light from the light source comprises reflection and diffusion.

12. The edge lit locally dimmed display according to claim 11, wherein the spread function comprises a spread function of 0.3d2 to 3d2 where d2 is a spacing between the lighting elements.

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

energizing a lighting device;

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

modulating the reflected light to produce a desired image;

wherein;

the reflected light comprises a low resolution version of a the desired image;

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

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

14. The locally dimmed display method according to claim 13, wherein the light source projects light in a direction substantially parallel to a plane of the spatial light modulator and the light from the light source is reflected to a direction that is substantially perpendicular to the plane of the spatial light modulator.

15. The locally dimmed display method according to claim 13, wherein the smoothly varying lighting elements comprise a spread function having a full width at half maximum of 0.3d2 to 3d2 where d2 is a spacing between the lighting elements at their origin.

16. The locally dimmed display method according to claim 14, wherein the smoothly varying lighting elements comprise a spread function having a full width at half maximum of 0.3d2 to 3d2 where d2 is a spacing between the lighting elements at their origin.