Waveguide and method of smoothing optical surfaces

• US 6,895,158 B2
• Filed: 12/09/2002
• Issued: 05/17/2005
• Est. Priority Date: 12/09/2002
• Status: Expired due to Fees

• Current Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Original Assignee: Eastman Kodak Company
• Inventors: Ram, Arunachalam T., Smith, Thomas M., Aylward, Peter T., Slater, Daniel A.
• Primary Examiner(s): Palmer, Phan T. H.
• Application Number:
  US10/314,661
• Publication Number:
  US 20040109659A1
• Time in Patent Office: 890 Days
• Field of Search: 385/15, 385/116, 385120-121, 385129-133, 385/901
• US Class Current: 385/133
• CPC Class Codes: G02B 6/08 with fibre bundle in form of plate
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

Disclosed is a waveguide having a light inlet surface and a viewing surface comprising stacked core layers separated by clad layers to form channels and bearing a smoothing layer on at least one of the light inlet surface or the viewing surface thereof.

Claims

1. A waveguide having a light inlet surface and a viewing surface comprising stacked core layers separated by clad layers to form channels and bearing a smoothing layer on at least one of the light inlet surface or the viewing surface thereof.

2. The waveguide of claim 1 wherein said smoothing layer comprises epoxy.

3. The waveguide of claim 2 wherein said epoxy is essentially fully crosslinked.

4. The waveguide of claim 1 wherein said smoothing layer further comprises material to modify its refractive index.

5. The waveguide of claim 4 wherein said material comprises at least one material selected from the group consisting of fluorinated polymer and transparent inorganic particles.

6. The waveguide of claim 1 wherein said surface bearing a smoothing layer is a light inlet surface.

7. The waveguide of claim 6 wherein said light inlet smoothing layer further provides adhesion to a light directing film.

8. The waveguide of claim 1 wherein said smoothing layer comprises a radiation curable compound.

9. The waveguide of claim 1 wherein said surface bearing a smoothing layer has a surface roughness of less than 1 Ra.

10. The waveguide of claim 1 wherein said surface bearing a smoothing layer has a roughness of between 0.001 and 0.5 Ra.

11. The waveguide of claim 1 wherein said inlet smoothing layer has a thickness of less than 200 micrometers.

12. The waveguide of claim 1 wherein said waveguide has a luminous flux of between 70 and 99%.

13. The waveguide of claim 1 wherein said smoothing layer further provides adhesion to a light directing film.

14. The waveguide of claim 1 wherein said surface bearing a smoothing layer is a light viewing surface.

15. The waveguide of claim 1 wherein said smoothing layer has a refractive index that is within ±

0.1 different from the refractive index of the core layer.

16. The waveguide of claim 1 wherein said smoothing layer comprises at least one material selected from the group consisting of epoxy and a radiation curable polymer.

17. The waveguide of claim 1 wherein said core layers comprise one material selected from the group consisting of polyolefin, polyester, polycarbonate, polyamide, polymethylmethacrylate, and their copolymer derivatives and glass.

18. The waveguide of claim 1 wherein said core layers comprise a polycarbonate polymer or copolymer.

19. The waveguide of claim 1 wherein said core layers comprise a polymethlymethacrylate compound.

20. The waveguide of claim 1 wherein said core layers comprise a glass.

21. The waveguide of claim 1 wherein said core layers have a gradient refractive index.

22. The waveguide of claim 1 wherein said clad layers are opaque.

23. The waveguide of claim 1 that is a planar waveguide.

24. The waveguide of claim 1 that is a fiber waveguide.

25. A display screen comprising the wavequide of claim 1.