LUMINANCE ENHANCEMENT STRUCTURE WITH VARYING PITCHES

• US 20100182351A1
• Filed: 01/20/2010
• Published: 07/22/2010
• Est. Priority Date: 01/22/2009
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink California, LLC (E Ink Corporation)
• Inventors: Lin, Craig
• Granted Patent: US 9,025,234 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G02B 27/60 Systems using moiré fringes
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133562 on the viewer side
• 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 structure for reflective display devices. The luminance enhancement structure comprises columns and grooves, wherein said grooves have a triangular cross-section and the pitches of the structure vary. The structure not only can enhance the brightness of a display device, but also can reduce the Moiré effect of the display device.

Claims

1. A luminance enhancement structure comprising columns and grooves, wherein said grooves have a triangular cross-section and the pitches of the structure vary.

2. The luminance enhancement structure of claim 1, wherein the apex angles of the triangular cross-section are substantially equal.

3. The luminance enhancement structure of claim 1, wherein the widths of the top surface of the columns are substantially equal.

4. The luminance enhancement structure of claim 1, wherein the widths of the open side of the triangular cross-section of the grooves vary.

5. The luminance enhancement structure of claim 1, wherein the surface of the grooves is optically flat and optionally coated with a metal layer.

6. The luminance enhancement structure of claim 1, which is formed from a material having a refractive index of about 1.4 to about 1.7.

7. The luminance enhancement structure of claim 1, which has a one dimensional configuration.

8. The luminance enhancement structure of claim 1, which has a two dimensional configuration.

9. The luminance enhancement structure of claim 1, wherein the pitch variance is of a fixed pattern.

10. The luminance enhancement structure of claim 1, wherein the pitch variance is random or pseudo-random.

11. The luminance enhancement structure of claim 1, wherein the pitch variance is a combination of random and fixed patterns.

12. A display device comprising an array of microcups and the luminance enhancement structure of claim 1 on the viewing side of the display device.

13. The display device of claim 12, wherein the apex angles of the triangular cross-section are substantially equal.

14. The display device of claim 12, wherein the widths of the top surface of the columns are substantially equal.

15. The display device of claim 12, wherein the widths of the open side of the triangular cross-section of the grooves vary.

16. The display device of claim 12, wherein the surface of the grooves is optically flat and optionally coated with a metal layer.

17. The display device of claim 12, wherein said microcups are filled with an electrophoretic fluid.

18. The display device of claim 17, further comprising two electrode layers.

19. The display device of claim 18, wherein one of the electrode layers comprises thin film transistor pixel electrodes.

20. The display device of claim 18, wherein one of the electrode layers is a patterned segment electrode layer.