Light extraction layer

• US 20070058391A1
• Filed: 09/14/2005
• Published: 03/15/2007
• Est. Priority Date: 09/14/2005
• Status: Abandoned Application

• Current Assignee: Rohm and Haas Denmark Finance A/S (Dow, Inc.)
• Original Assignee: Rohm and Haas Denmark Finance A/S (Dow, Inc.)
• Inventors: Wilson, Randall, Lee, Junwon
• Application Number:
  US11/226,141
• Publication Number:
  US 20070058391A1
• Time in Patent Office: Days
• US Class Current: 362/606
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer

Abstract

A light extraction layer and a display having a light extraction layer are described.

Claims

1. A light extraction layer, comprising:

a first end portion and a central portion;

a first side and a second side; and

a plurality of light extraction features disposed over the first side, wherein at least two of the light extraction features have different lengths and an optical contact ratio is greater at the central portion than at the first end portion.

2. A light extraction layer as recited in claim 1, further comprising a second end portion, wherein the optical contact ratio is greater at the central portion than at the second end portion.

3. A light extraction layer as recited in claim 1, wherein the light extraction features have a pitch and the pitch is substantially constant across the layer.

4. A light extraction layer as recited in claim 1, wherein each of the light extracting features has a contact width and the contact widths of at least two of the light extracting features are not the same.

5. A light extraction layer as recited in claim 1, wherein the length of at least another two of the light extraction features is the same.

6. A light extraction layer as recited in claim 1, wherein a length of at least one of the light extraction features disposed at the central portion is greater than a length of at least one of the light extraction features at the first end portion.

7. A light extraction layer as recited in claim 1, wherein the optical contact ratio further varies in the direction of the length of the light extraction features.

8. A light extraction layer as recited in claim 1, wherein each of the plurality of light extraction features has curved surfaces.

9. A light extraction layer as recited in claim 8, wherein the curved surfaces are substantially parabolic.

10. A light extraction layer as recited in claim 8, wherein the curved surfaces are substantially aspheric.

11. A light extraction layer as recited in claim 8, wherein the curved surfaces are substantially composite in cross-section.

12. A light extraction layer as recited in claim 1, wherein each of the light extraction features has a lower surface that includes a base portion, which is adapted to be disposed in a material and the lower surface is substantially in a plane of a surface of the material.

13. A light extraction layer as recited in claim 12, wherein the material is an adhesive.

14. A light extraction layer as recited in claim 1, further comprising a substrate that is integral with the plurality of light extraction features and each of the light extraction features reflects light in a direction that is substantially orthogonal to the substrate.

15. A light extraction layer as recited in claim 1, further comprising a substrate that is integral with the plurality of light extraction features and each of the light extraction features reflects light in a direction that is not substantially orthogonal to the substrate.

16. A light extraction layer as recited in claim 1, further comprising a substrate that is integral with the plurality of light extraction features, wherein the substrate has a thickness in the range of approximately 10.0 micrometers to approximately 1.0 mm.

17. A light extraction layer as recited in claim 1, wherein at least two of the plurality of light extraction features have a random distribution in at least one portion of the layer.

18. A display device, comprising:

a light modulator;

a light guide having a first end, a second end, a top surface, and a bottom surface;

at least one light source coupled to the first end, or the second end, or both;

a light extraction layer disposed over the top surface, wherein the light extraction layer comprises;

a first end portion, a second end portion and a central portion;

a first side and a second side; and

a plurality of light extraction features disposed over the top surface, wherein at least two of the light extraction features have different lengths and an optical contact ratio between the light extraction layer and the light guide is greater at the central portion than at the first end portion.

19. A display device as recited in claim 18, wherein the light extraction features have a pitch and the pitch is substantially constant across the layer.

20. A display device as recited in claim 19, wherein the optical contact ratio between the light extraction layer and the light guide is greater at the central portion than at the second end portion.

21. A display device as recited in claim 20, wherein each of the light extraction features has a contact width and the contact widths of at least two of the plurality of light extraction features are not the same.

22. A display device as recited in claim 21, wherein the length of at least another two of the light extraction features is the same.

23. A display device as recited in claim 18, wherein a length of at least one of the light extraction features disposed at the central portion is greater than a length of at least one of the light extraction features at the first end portion.

24. A display device as recited in claim 18, wherein the optical contact ratio further varies in the direction of the length of the light extraction features.

25. A display device as recited in claim 18, wherein each of the plurality of light extraction features has curved surfaces.

26. A display device as recited in claim 18, wherein the curved surfaces are substantially parabolic.

27. A display device as recited in claim 18, wherein the curved surfaces are substantially aspheric.

28. A display device as recited in claim 18, wherein the curved surfaces are composite in cross-sectional shape.

29. A display device as recited in claim 18, wherein each of the light extraction features has a lower surface that includes a base portion, which is adapted to be disposed in a material and the lower surface is substantially in a plane of a surface of the material.

30. A display device as recited in claim 29, wherein the material is an adhesive.

31. A display device as recited in claim 18, further comprising a substrate that is integral with the plurality of light extraction features and each of the light extraction features reflects light in a direction that is substantially orthogonal to the substrate.

32. A display device as recited in claim 18, further comprising a substrate that is integral with the plurality of light extraction features and each of the light extraction features reflects light in a direction that is not substantially orthogonal to the substrate.

33. A display device as recited in claim 18, further comprising a substrate that is integral with the plurality of light extraction features, wherein the substrate has a thickness in the range of approximately 10.0 μ

m to approximately 1.0 mm.

34. A display device as recited in claim 18, wherein at least two of the plurality of light extraction features have a random distribution in at least one portion of the layer.

35. A display device as recited in claim 18, wherein the light guide has a plurality of microstructures disposed over the bottom surface.

36. A display device as recited in claim 35, wherein the microstructures are substantially elongated in shape in a direction perpendicular to the first end of the light guide.

37. A display device as recited in claim 35, wherein at least one of the microstructures has a finite length that is less than the length of the light guide.

38. A display device as recited in claim 35, wherein the microstructures are disposed randomly, staggered, or overlapped.

39. A display device as recited in claim 35, wherein the microstructures are prismatic, arc, semi-circular, conic, aspherical, trapezoidal, or a composite of at least two shapes in cross-section.