LUMINANCE ENHANCEMENT STRUCTURE FOR REFLECTIVE DISPLAY DEVICES

• US 20100225999A1
• Filed: 03/08/2010
• Published: 09/09/2010
• Est. Priority Date: 03/09/2009
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: SiPix Imaging, Inc. (E Ink Holdings Incorporated)
• Inventors: Sprague, Robert A., Lin, Craig
• Granted Patent: US 8,120,836 B2
• Time in Patent Office: Days
• US Class Current: 359/296
• CPC Class Codes: G02F 1/133524 Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1677 Structural association of cells with optical devices, e.g. reflectors or illuminating devices

Abstract

The present invention is directed to luminance enhancement structures for reflective display devices. The structure comprises columns and grooves, wherein each of said grooves has a cross-section comprising an apex angle and two edge lines. The structure increases the overall reflectance by reducing the total internal reflection, and as a result, the brightness of a display device is increased.

Claims

1. A luminance enhancement structure comprising columns and grooves, wherein each of said grooves has a cross-section comprising an apex angle and two edge lines.

2. The structure of claim 1, which has a one dimensional configuration.

3. The structure of claim 1, which has a two dimensional configuration.

4. The structure of claim 2, wherein said two edge lines are straight lines and the apex angles of the grooves are not the same throughout the structure.

5. The structure of claim 4, wherein the two edge lines of the cross-section are substantially equal for all grooves.

6. The structure of claim 4, wherein the two edge lines are substantially equal for some of the grooves and the two edge lines are not equal for the remaining grooves.

7. The structure of claim 4, wherein the two edge lines are not equal for all grooves.

8. The structure of claim 4, wherein the heights of the grooves are substantially equal throughout the structure.

9. The structure of claim 4, wherein the heights of the grooves vary.

10. The structure of claim 4, wherein the pitches of the grooves are substantially equal for all grooves throughout the structure.

11. The structure of claim 4, wherein the pitches of the grooves vary.

12. The structure of claim 2, wherein each of the two edge lines comprise two or more segments of straight line and the different segments of the straight line have different edge line angles.

13. The structure of claim 12, wherein the apex angles of the grooves are substantially equal for all grooves throughout the structure.

14. The structure of claim 12, wherein the edge lines appear curved.

15. The structure of claim 14, wherein the curved edge lines have more than one curvature.

16. The structure of claim 12, wherein the two edge lines of a single groove have different numbers of segments of the straight line.

17. The structure of claim 2, wherein said apex angle is in the range of about 5°

to about 50°

.

18. The structure of claim 17, wherein said apex angle is in the range of about 20°

to about 40°

.

19. The structure of claim 2, wherein the surface of the grooves is not coated.

20. A display device assembly comprising

a) a display panel which comprises an array of display cells filled with a display fluid;

and

luminance enhancement structure of claim 1 on the viewing side of the display device.