Area active backlight with steerable light source

• US 20100188610A1
• Filed: 01/28/2009
• Published: 07/29/2010
• Est. Priority Date: 01/28/2009
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Feng, Xiao-fan
• Granted Patent: US 7,982,822 B2
• Time in Patent Office: Days
• US Class Current: 349/65
• CPC Class Codes: G02F 1/133601 for spatial active dimming
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 2201/06 integrated waveguide
• CPC Class Codes: G02F 2203/026 attenuated or frustrated internal reflection
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines

Abstract

A liquid crystal display includes a backlight. The backlight includes a plurality of waveguides to selectively direct light. A set of selection elements in combination with the backlight selectively direct light to the front of the display.

Claims

1. A display comprising:

(a) a liquid crystal layer;

(b) a backlight that provides light to said liquid crystal layer;

(c) said liquid crystal layer selectively modifying the transmission of light from said backlight to the front of said display;

(d) said backlight includes a plurality of spaced apart light waveguides;

(e) said display includes a plurality of selection elements associated with said light waveguides that selectively direct light toward said liquid crystal layer;

(f) wherein the combination of said waveguides and said selection elements provide light to said front of said display in a temporal manner.

2. The display of claim 1 wherein said backlight includes a plurality of light emitting diodes that provides light to respective said waveguides.

3. The display of claim 1 wherein said backlight includes a plurality of one-dimensional said waveguides.

4. The display of claim 1 wherein said selection elements are light extractors.

5. The display of claim 1 wherein said selection elements use frustrated total internal reflection.

6. The display of claim 1 wherein said selection elements include micro optical structures.

7. The display of claim 6 wherein said micro optic structures include a thin film layer forming a lens and shutter.

8. The display of claim 1 wherein said temporal aspect of said combination results in a decrease in motion blur.

9. The display of claim 1 wherein a plurality of said waveguides extend across the entire said display.

10. The display of claim 9 wherein said plurality of said waveguides are arranged in a parallel arrangement with respect to one another.

11. The display of claim 1 further including a light steering mechanism that selectively directs light to at least one, and less than all, of said light waveguides at any particular time.

12. The display of claim 11 wherein said light steering mechanism is scanned from top to bottom of said display.

13. The display of claim 1 wherein at least one of said selection elements is associated with a respective one of said plurality of waveguides.

14. The display of claim 13 wherein for a respective one of said plurality of waveguides that light is only substantially emitted from said respective guide at a position associated with a selected respective one of said selection elements.

15. The display of claim 11 wherein said light steering mechanism includes a mechanical shutter.

16. The display of claim 1 wherein said combination results in a temporal multiplexed illumination of said display.

17. The display of claim 1 wherein regions of an image to be displayed that is determined not to have motion have a slower rate of providing light to said waveguides than regions of said image to be display that is determined to have motion.

18. A display comprising:

(a) a liquid crystal layer;

(b) a backlight that provides light to said liquid crystal layer;

(c) said liquid crystal layer selectively modifying the transmission of light from said backlight to the front of said display;

(d) said backlight includes a plurality of spaced apart light waveguides arranged in a one-dimensional parallel array extending from one side to the other side of said display;

(e) said backlight includes at least one light source associated with each of said waveguides;

(f) said display includes a plurality of selection elements associated with each of said waveguides such that selective activation of one of said selection elements causes light to pass through said associated waveguide that is directed direct light toward said liquid crystal layer while light does not similarly pass through said associated waveguide where one of said selection element is not selected;

(g) each of said waveguides are provided with light in a sequential manner while a plurality of associated selection elements for each of said waveguides are selected so that light is selectively emitted from each of said respective waveguide.

19. The display of claim 18 wherein regions of an image to be displayed that is determined not to have motion have a slower rate of providing light to said waveguides than regions of said image to be display that is determined to have motion.