Light redirecting films and film systems

• US 6,752,505 B2
• Filed: 07/19/2001
• Issued: 06/22/2004
• Est. Priority Date: 02/23/1999
• Status: Expired due to Fees

• Current Assignee: Delaware Display Group LLC (Acacia Research Corporation)
• Original Assignee: Solid State Opto Limited (Global Lighting Technologies Inc.)
• Inventors: McCollum, Timothy A., Ezell, Robert M., Parker, Jeffery R.
• Primary Examiner(s): Sember, Thomas M.
• Application Number:
  US09/909,318
• Publication Number:
  US 20010053075A1
• Time in Patent Office: 1,069 Days
• Field of Search: 362/31, 362/330, 362/328, 362/329, 362/26, 362/331, 362/339, 362/337, 362/336, 362/335, 362/332, 349/62, 349/64, 349/65, 349/113
• US Class Current: 362/627
• CPC Class Codes: A61B 2090/309 using white LEDs
• CPC Class Codes: A61M 2021/0044 by the sight sense
• CPC Class Codes: A61M 21/02 for inducing sleep or relaxation, e.g. by direct nerve stimulation, hypnosis, analgesia for massage A61H; electrotherapy A61N, e.g. applying alternating or intermittent electric currents for producing anaesthesia A61N1/36021
• CPC Class Codes: A61N 2005/063 comprising light transmitting means, e.g. optical fibres
• CPC Class Codes: A61N 2005/0652 Arrays of diodes
• CPC Class Codes: A61N 5/0621 Hyperbilirubinemia, jaundice treatment
• CPC Class Codes: F21V 11/00 Screens not covered by groups F21V1/00, F21V3/00, F21V7/00 or F21V9/00 characterised by cooling arrangements F21V29/502
• CPC Class Codes: F21V 5/10 comprising photoluminescent material
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/006 to produce indicia, symbols, texts or the like
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02B 6/0068 : Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: H01H 2219/062 : Light conductor
• CPC Class Codes: H01H 2221/07 : transparent

Abstract

Light redirecting films include a pattern of individual optical elements of well defined shape on the light exit surface of the films for refracting the light entering the entrance surface of the films from a backlight toward a direction normal to the exit surface. The individual optical elements overlap and intersect each other. Also, the orientation, size and/or shape of the optical elements may be tailored to redirect more of the incident light from the backlight within a desired viewing angle.

Claims

1. A light redirecting film comprising a thin optically transparent substrate having opposite sides, individual optical elements of well defined shape on or in the substrate for redirecting at least some light passing through one side and out the other side in a predetermined beam pattern, the optical elements being quite small in relation to a width and length of the substrate, at least some of the optical elements having at least two sloping surfaces that intersect each other to form a ridge having ends that intersect the substrate or another optical element where the ridge ends, the optical elements overlapping, intersecting or interlocking each other such that the optical elements substantially cover at least one of the sides of the substrate.

2. The film of claim 1 wherein the size of at least some of the optical elements varies across the film.

3. The film of claim 1 wherein the density of at least some of the optical elements varies across the film.

4. The film of claim 1 wherein at least some of the optical elements have an angled surface that varies in area across the film.

5. The film of claim 1 wherein at least some of the optical elements vary in depth or height across the film.

6. The film of claim 1 wherein the orientation of at least some of the optical elements varies across the film.

7. The film of claim 1 wherein at least some of the optical elements have angled surfaces that vary in height or depth across the film.

8. The film of claim 1 wherein at least some of the optical elements are arranged in groupings across the film, at least some of the optical elements in each of the groupings having at least one different shape characteristic that collectively produces an average shape characteristic for each of the groupings.

9. The film of claim 8 wherein the average shape characteristic of at least some of the groupings varies across the film.

10. The film of claim 8 wherein at least some of the optical elements in each of the groupings have a different depth or height that collectively produce an average depth or height characteristic for each of the groupings.

11. The film of claim 10 wherein the average depth or height characteristic for at least some of the groupings varies across the film.

12. The film of claim 8 wherein at least some of the optical elements in each of the groupings have a different slope angle that collectively produce an average slope angle for each of the groupings.

13. The film of claim 12 wherein the average slope angle for each of the groupings varies across the film.

14. The film of claim 8 wherein at least some of the optical elements in each of the groupings have a different orientation that collectively produce an average orientation for each of the groupings.

15. The film of claim 14 wherein the average orientation for at least some of the groupings varies across the film.

16. The film of claim 1 wherein at least some of the optical elements in each of the groupings have a different width or length that collectively produce an average width or length for each of the groupings.

17. The film of claim 16 wherein the average width or length for at least some of the groupings varies across the film.

18. The film of claim 1 wherein at least some of the optical elements are oriented at different angles across the substrate for redirecting light along different axes.

19. The film of claim 1 wherein at least the one side of the substrate is smooth.

20. The film of claim 1 wherein at least the one side of the substrate is coated with an optical coating.

21. The film of claim 1 wherein at least the one side of the substrate has a matte or texture finish.

22. The film of claim 1 wherein the ridge of the optical elements is in a single plane.

23. The film of claim 1 wherein at least some of the optical elements intersect the substrate at different angles.

24. The film of claim 1 wherein the light that enters the one side of the substrate is received from a backlight, and at least some of the optical elements differ in size, shape, angle or orientation to redistribute more of the light emitted by the backlight in a desired viewing angle.

25. The film of claim 1 wherein at least some of the optical elements only have one ridge.

26. The film of claim 1 wherein the ridge has a maximum height intermediate the ends of the ridge.

27. The film of claim 1 wherein the ridge has a maximum depth intermediate the ends of the ridge.

28. The film of claim 1 wherein at least some of the optical elements are on or in the one side, the other side or both sides of the substrate.

29. The film of claim 1 wherein at least some of the optical elements have at least one planar surface and at least one curved surface.

30. The film of claim 29 wherein the ratio of the planar surface to the curved surface of the optical elements is selected to produce a desired viewing angle.

31. The film of claim 29 wherein the curvature of the curves surface of the optical elements is selected to produce a desired viewing angle.

32. The film of claim 1 wherein at least same of the optical elements have at least two planar surfaces.

33. The film of claim 1 wherein at least some of the optical elements have at least two curved surfaces.

34. The film of claim 1 wherein at least some of the optical elements have at least two sloping surfaces that intersect the substrate or another optical element.

35. The film of claim 1 wherein at least some of the optical elements or the optical element surfaces are rotated or intersect the substrate at different angles.

36. The film of claim 1 which comprises two layers of the film that are rotated with respect to each other.

38. The film of claim 1 wherein the optical elements randomly overlap, intersect or interlock each other.

37. A light redirecting film comprising a thin optically transparent substrate having opposite sides, individual optical elements of well defined shape on or in the substrate to redistribute at least some light entering one side and exiting the other side toward a direction normal to the substrate, the optical elements being quite small in relation to a width and length of the substrate, at least some of the optical elements having at least two sloping surfaces that intersect each other to form a ridge having ends, the ridge of at least some of the optical elements being in generally the same direction, the optical elements overlapping, intersecting or interlocking each other such that the optical elements substantially cover at least one of the sides of the substrate.

39. The film of claim 37 wherein at least some of the optical elements are on or an the one side, the other side or both sides of the substrate.

40. The film of claim 37 wherein the ridge of at least some of the optical elements is in the same plane.

41. A light redirecting film comprising a thin optically transparent substrate having opposite sides, individual optical elements of well defined shape on or in the substrate to redistribute at least some light entering one side and exiting the other side toward a direction normal to the substrate, at least some of the optical elements having a greater length than width, the optical elements being quite small in relation to a width and length of the substrate, at least some of the optical elements having at least two sloping surfaces that intersect each other to form a ridge with end points, the ridge of at least some of the optical elements being generally parallel to the length direction of the optical elements, at least some of the optical elements overlapping, intersecting or interlocking each other.

42. The film of claim 41 wherein at least some of the optical elements are on or in the one side, the other side or both sides of the substrate.

43. A light redirecting film comprising a thin optically transparent substrate having opposite sides, individual optical elements of well defined shape on or in the substrate to redistribute at least some light entering one side and exiting the other side toward a direction normal to the substrate, at least some of the optical elements having a greater length than width, the optical elements being quite small in relation to a width and length of the substrate, a least some of the optical elements having at least two sloping surfaces that intersect each other to form a ridge with and points, the ridge of at least some of the optical elements being generally parallel to the length direction of the optical elements, the optical elements overlapping, intersecting or interlocking each other to substantially cover at least one of the sides of the substrate.

44. The film of claim 43 wherein the optical elements randomly overlap, intersect or interlock each other.