Light enhancing structures with multiple arrays of elongate features of varying characteristics

• US 7,674,028 B2
• Filed: 11/08/2006
• Issued: 03/09/2010
• Est. Priority Date: 01/13/2006
• Status: Active Grant

• Current Assignee: Avery Dennison Corporation
• Original Assignee: Avery Dennison Corporation
• Inventors: Chapman, Steven R., Cassarly, William J.
• Primary Examiner(s): Peng; Charlie
• Assistant Examiner(s): LAM, HUNG Q
• Application Number:
  US11/594,699
• Publication Number:
  US 20070091616A1
• Time in Patent Office: 1,217 Days
• Field of Search: 385/14, 385/15, 385/16, 385/17, 385/18, 385/31, 385/36, 385/122, 385/129, 385/130, 385/131, 385/132, 385/146, 362/341, 362/600, 362/339, 362/627
• US Class Current: 362/600
• CPC Class Codes: G02B 3/0025 Machining, e.g. grinding, polishing, diamond turning, manufacturing of mould parts
• CPC Class Codes: G02B 3/0031 Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
• CPC Class Codes: G02B 5/021 the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
• CPC Class Codes: G02B 5/0236 the diffusion taking place within the volume of the element
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/045 Prism arrays
• 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
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses

Abstract

Various embodiments comprise light recycling films comprising an array of parallel ridges and grooves that form prisms that selectively reflect or transmit light. In some embodiments, the light recycling film may be used in displays that include spatial light modulators comprising a plurality of pixels. The light recycling film can limit the field-of-view of the display and enhance the luminance within that field-of-view. Various embodiments comprising multiple arrays of ridges and/or grooves can enhance uniformity of illumination of the pixels in the spatial light modulator and reduce Moiré effects.

Claims

1. An optical member comprising an array of total internal reflection structures, said optical member comprising:

a substantially optically transmissive film having a surface;

a first plurality of non-intersecting elongate features in said surface; and

a second plurality of non-intersecting elongate features in said surface, said first plurality of non-intersecting elongate features angled with respect to said second plurality of non-intersecting elongate features,

wherein each of said non-intersecting elongate features in said first plurality extends across said non-intersecting elongate features in said second plurality of non-intersecting elongate features thereby forming said total internal reflection structures, and

wherein said non-intersecting elongate features comprise grooves and the depth of at least a portion of said second plurality of non-intersecting elongate features is smaller than the depth of at least a portion of said first plurality of non-intersecting elongate features but that is greater than 50% of the depth of said portion of said first plurality of non-intersecting elongate features.

2. The optical member of claim 1, wherein the depth of at least some non-intersecting elongate features in said first plurality are unequal.

3. The optical member of claim 1, wherein the depth of at least some non-intersecting elongate features in said second plurality are unequal.

4. The optical member of claim 1, wherein the depth of at least some non-intersecting elongate features in said first plurality increases and decreases across a portion of said surface.

5. The optical member of claim 1, wherein at least one of said non-intersecting elongate features varies in depth along its length.

6. The optical member of claim 1, wherein at least two of said non-intersecting elongate features comprise substantially parallel linear features.

7. The optical member of claim 1, wherein said non-intersecting elongate features comprise a non-linear feature.

8. The optical member of claim 7, wherein said non-linear feature undulates laterally.

9. The optical member of claim 1, wherein at least one of said total internal reflection structures comprises a prism having planar facets.

10. The optical member of claim 9, wherein said prism comprises a pyramid.

11. The optical member of claim 9, wherein said planar facets have rounded edges.

12. The optical member of claim 9, wherein each of said facets has substantially the same projected area.

13. The optical member of claim 1, wherein at least two of said total internal reflection structures have different heights.

14. The optical member of claim 1, wherein at least one of said total internal reflection structures comprises curved surfaces that totally internally reflect light.

15. The optical member of claim 1, further comprising a third plurality of non-intersecting elongate features in said surface, said third plurality of non-intersecting elongate features angled with respect to said first plurality of non-intersecting elongate features and said second plurality of non-intersecting elongate features.

16. The optical member of claim 15, wherein at least a portion of said third plurality of non-intersecting elongate features has a height or depth that is the same as the height or depth of one of said first and second pluralities of non-intersecting elongate features.

17. The optical member of claim 15, wherein at least a portion of said third plurality of non-intersecting elongate features has a height or depth that is different than said heights or depths of both of said first and second pluralities of non-intersecting elongate features.

18. The optical member of claim 1, wherein at least one of said non-intersecting elongate features has a vertex angle of about 90°

.

19. The optical member of claim 1, further comprising a diffuser on either side of said surface.

20. The optical member of claim 1, wherein at least one of said non-intersecting elongate features is linear.

21. An optical apparatus comprising the optical member of claim 1 and an illumination apparatus that backlights said optical member.

22. The optical member of claim 1, wherein each of said non-intersecting elongate features in said first plurality intersect each of said non-intersecting elongate features in said second plurality only once.

23. The optical member of claim 1, wherein said first plurality of non-intersecting elongate features are oriented at an acute angle with respect to said second plurality of non-intersecting elongate features.

24. An optical member comprising an array of total internal reflection structures, said optical member comprising:

a substantially optically transmissive film having a surface;

a first plurality of non-intersecting elongate features in said surface; and

a second plurality of non-intersecting elongate features in said surface, said first plurality of non-intersecting elongate features angled with respect to said second plurality of non-intersecting elongate features,

wherein each of said non-intersecting elongate features in said first plurality extends across said non-intersecting elongate features in said second plurality of non-intersecting elongate features thereby forming said total internal reflection structures, and

wherein said non-intersecting elongate features comprise ridgelines and the height of at least a portion of said second plurality of non-intersecting elongate features is smaller than the height of at least a portion of said first plurality of non-intersecting elongate features but that is greater than 50% of the height of said portion of said first plurality of non-intersecting elongate features.

25. The optical member of claim 24, wherein the height of at least some non-intersecting elongate features in said first plurality are unequal.

26. The optical member of claim 24, wherein the height of at least some non-intersecting elongate features in said second plurality are unequal.

27. The optical member of claim 24, wherein the height of at least some non-intersecting elongate features in said first plurality increases and decreases across a portion of said surface.

28. The optical member of claim 24, wherein at least one of said non-intersecting elongate features varies in height along its length.

29. The optical member of claim 24, wherein at least two of said non-intersecting elongate features comprise substantially parallel linear features.

30. The optical member of claim 24, wherein said non-intersecting elongate features comprise a non-linear feature.

31. The optical member of claim 30, wherein said non-linear feature undulates laterally.

32. The optical member of claim 24, wherein at least one of said total internal reflection structures comprises a prism having planar facets.

33. The optical member of claim 32, wherein said prism comprises a pyramid.

34. The optical member of claim 32, wherein said planar facets have rounded edges.

35. The optical member of claim 32, wherein each of said facets has substantially the same projected area.

36. The optical member of claim 24, wherein at least two of said total internal reflection structures have different heights.

37. The optical member of claim 24, wherein at least one of said total internal reflection structures comprises curved surfaces that totally internally reflect light.

38. The optical member of claim 24, further comprising a third plurality of non-intersecting elongate features in said surface, said third plurality of non-intersecting elongate features angled with respect to said first plurality of non-intersecting elongate features and said second plurality of non-intersecting elongate features.

39. The optical member of claim 38, wherein at least a portion of said third plurality of non-intersecting elongate features has a height or depth that is the same as the height or depth of one of said first and second pluralities of non-intersecting elongate features.

40. The optical member of claim 38, wherein at least a portion of said third plurality of non-intersecting elongate features has a height or depth that is different than said heights or depths of both of said first and second pluralities of non-intersecting elongate features.

41. The optical member of claim 38, wherein at least one of said non-intersecting elongate features has a vertex angle of about 90°

.

42. The optical member of claim 38, further comprising a diffuser on either side of said surface.

43. The optical member of claim 38, wherein at least one of said non-intersecting elongate features is linear.

44. An optical apparatus comprising the optical member of claim 38 and an illumination apparatus that backlights said optical member.

45. The optical member of claim 38, wherein each of said non-intersecting elongate features in said first plurality intersect each of said non-intersecting elongate features in said second plurality only once.