LUMINANCE ENHANCEMENT STRUCTURE WITH MOIRE REDUCING DESIGN

• US 20100141573A1
• Filed: 11/30/2009
• Published: 06/10/2010
• Est. Priority Date: 12/05/2008
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: SiPix Imaging, Inc. (E Ink Holdings Incorporated)
• Inventors: Lin, Craig
• Granted Patent: US 8,441,414 B2
• Time in Patent Office: Days
• US Class Current: 345/107
• CPC Class Codes: G02B 17/006 Systems in which light light is reflected on a plurality of parallel surfaces, e.g. louvre mirrors, total internal reflection [TIR] lenses Fresnel mirrors G02B5/09, Fresnel lenses G02B3/08
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02F 1/133507 Films for enhancing the luminance

Abstract

The present invention is directed to luminance enhancement structure for reflective display devices. The structure not only can enhance the brightness of a display device, but also can reduce the Moiré effect of the display device. The present invention is also directed to a display device comprising an array of microcups and a luminance enhancement structure.

Claims

1. A luminance enhancement structure comprising columns and grooves wherein said columns have wavy edges.

2. The luminance enhancement structure of claim 1, wherein said grooves have a triangular cross-section.

3. The luminance enhancement structure of claim 2, wherein the surface of the grooves is optically flat and optionally coated with a metal layer.

4. The luminance enhancement structure of claim 1, which has a thickness in the range of about 10 μ

m to about 200 μ

m.

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

6. The luminance enhancement structure of claim 1, wherein said wavy edges shift in the X direction while the columns themselves extend in the Z direction.

7. The luminance enhancement structure of claim 1, wherein the widths of the top surface of the columns are equal when cross-sectioned by parallel lines.

8. The luminance enhancement structure of claim 1, wherein the grooves have the same apex angle.

9. The luminance enhancement structure of claim 1, wherein the variance of the shift of the wavy edges is within 15% of the nominal or average period of the variance in the Z direction.

10. The luminance enhancement structure of claim 1, wherein no column has a shift pattern of the wavy edges matching the shift pattern of another column within 10 or more columns.

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

12. The display device of claim 11, wherein said grooves have a triangular cross-section.

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

14. The display device of claim 11, wherein said luminance enhancement structure has a thickness in the range of about 10 μ

m to about 200 μ

m.

15. The display device of claim 11, wherein said luminance enhancement structure is formed from a material having a refractive index of about 1.4 to 1.7.

16. The display device of claim 11, wherein said wavy edges shift in the X direction while the columns themselves extend in the Z direction.

17. The display device of claim 11, wherein the widths of the top surface of the columns are equal when cross-sectioned by parallel lines.

18. The display device of claim 11, wherein the grooves have the same apex angle.

19. The display device of claim 11, wherein the variance of the shift of the wavy edges is within 15% of the nominal or average period of the variance in the Z direction.

20. The display device of claim 11, wherein no column has a shift pattern of the wavy edges matching the shift pattern of another column within 10 or more columns.

21. The display device of claim 11, wherein said microcups are filled with an electrophoretic fluid.

22. The display device of claim 11, further comprising two electrode layers.

23. The display device of claim 22, wherein one of the electrode layers comprises thin film transistor pixel electrodes.

24. The display device of claim 22, wherein one of the electrode layers is a patterned segment electrode layer.