Hybrid lightguide backlight

• US 20050135117A1
• Filed: 12/23/2003
• Published: 06/23/2005
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Watson, Philip E., Lamb, David J., O'Neill, Mark B., Epstein, Kenneth A., Gardiner, Mark E., Marushin, Patrick H., Kotchick, Keith M.
• Granted Patent: US 7,223,005 B2
• Time in Patent Office: Days
• US Class Current: 362/615
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area

Abstract

Backlighting systems are disclosed, which include a lightguide with at least one light source optically connected to an edge of the lightguide for supplying light into its interior and a reflective cavity with at least one light source optically connected to the reflective cavity for supplying light into its interior. The reflective cavity may include a first reflector and a second reflector and at least one source may be disposed at an edge of the reflective cavity. Alternatively, the reflective cavity may include a back reflector portion and light sources may be disposed at the back reflector portion.

Claims

1. A backlighting system, comprising:

a lightguide having an interior;

at least one light source optically connected to an edge of the lightguide for supplying light into the interior thereof;

a reflective cavity having an interior; and

at least one light source optically connected to the reflective cavity for supplying light into the interior thereof.

2. The backlighting system as recited in claim 1, wherein at least one light source optically connected to the reflective cavity is disposed at an edge of the reflective cavity.

3. The backlighting system as recited in claim 1, wherein at least one light source optically connected to the reflective cavity is disposed in the interior of the reflective cavity.

4. The backlighting system as recited in claim 1, wherein at least one light source optically connected to the reflective cavity is disposed at an edge of the reflective cavity and at least one light source optically connected to the reflective cavity is disposed in the interior of the reflective cavity.

32. The backlighting system as recited in claim 1, 5 or 20, further comprising a first recycling enhancement structure disposed at a surface of the lightguide.

33. The backlighting system as recited in claim 1, 5 or 20, further comprising a first recycling enhancement structure disposed at a surface of the lightguide, said first recycling enhancement structure comprising a reflective polarizer.

34. The backlighting system as recited in claim 1, 5 or 20, further comprising a first recycling enhancement structure disposed at a surface of the lightguide, said first recycling enhancement structure comprising a reflective polarizer and a diffuser.

35. The backlighting system as recited in claim 1, 5 or 20, further comprising a first recycling enhancement structure disposed at a surface of the lightguide, said first recycling enhancement structure comprising a reflective polarizer and a prismatic structure.

36. The backlighting system as recited in claim 1, 5 or 20, further comprising a first recycling enhancement structure attached to a surface of the lightguide.

37. The backlighting system as recited in claim 1, 5 or 20, further comprising a second recycling enhancement structure disposed between the lightguide and the reflective cavity.

38. The backlighting system as recited in claim 1, 5 or 20, further comprising a second recycling enhancement structure disposed between the lightguide and the reflective cavity, said second recycling enhancement structure comprising a prismatic structure.

39. The backlighting system as recited in claim 1, 5 or 20, further comprising a second recycling enhancement structure disposed between the lightguide and the reflective cavity, said second recycling enhancement structure comprising a first prismatic structure and a second prismatic structure.

40. The backlighting system as recited in claim 1, 5 or 20, further comprising a second recycling enhancement structure attached to a surface of the lightguide.

5. A backlighting system, comprising:

a lightguide having an interior;

at least one light source optically connected to a first edge of the lightguide for supplying light into the interior thereof;

a reflective cavity having an interior; and

at least one light source optically connected to a first edge of the reflective cavity for supplying light into the interior thereof.

6. The backlighting system as recited in claim 5, wherein the first edge of the first lightguide is substantially aligned with the first edge of the reflective cavity.

7. The backlighting system as recited in claim 5, wherein the first edge of the first lightguide is not aligned with the first edge of the reflective cavity.

8. The backlighting system as recited in claim 5, further comprising a collimating structure disposed over a light source optically connected to the reflective cavity.

9. The backlighting system as recited in claim 5, further comprising a diffuse extractor for extracting light from the reflective cavity.

10. The backlighting system as recited in claim 5, wherein the reflective cavity comprises a first reflector and a second semi-transparent reflector disposed between the lightguide and the first reflector, the first reflector and the second semi-transparent reflector defining the interior of the reflective cavity.

11. The backlighting system as recited in claim 10, wherein the first reflector is semi-transparent.

12. The backlighting system as recited in claim 10, wherein the reflective cavity further comprises at least one light source optically connected to a second edge of the reflective cavity for supplying light into the interior thereof.

13. The backlighting system as recited in claim 12, further comprising a first collimating structure disposed over the at least one light source optically connected to the first edge of the reflective cavity and a second collimating structure over the at least one light source optically connected to the second edge of the reflective cavity.

14. The backlighting system as recited in claim 13, wherein the first and second collimating structures comprise prismatic structures having grooves generally parallel to the first and second reflectors and having prism apexes generally facing the interior of the reflective cavity.

15. The backlighting system as recited in claim 13, wherein the first and second collimating structures each comprise a two-dimensional Fresnel lens having a focal line.

16. The backlighting system as recited in claim 15, wherein the light sources are disposed near the focal lines of the two-dimensional Fresnel lenses.

17. The backlighting system as recited in claim 16, wherein the light sources include a linear array of LEDs.

18. The backlighting system as recited in claim 13, wherein the second semi-transparent reflector comprises prismatic structures having prism apexes facing generally away from the reflective cavity, and the first and second collimating structures are configured so that they transmit light substantially within a numerical aperture of the prismatic structures.

19. The backlighting system as recited in claim 13, wherein the first and second collimating structures each include a reflective polarizer having a pass axis and the second semi-transparent reflector includes a reflective polarizer having a pass axis generally orthogonal to the pass axes of the reflective polarizers included into the collimating structures.

20. A backlighting system, comprising:

a lightguide having an interior;

at least one light source optically connected to a first edge of the lightguide for supplying light into the interior thereof;

a reflective cavity having an interior; and

at least one light source disposed in the interior of the reflective cavity.

21. The backlighting system as recited in claim 20, wherein the reflective cavity comprises a back reflector portion and at least one light source is disposed at the back reflector portion.

22. The backlighting system as recited in claim 21, further comprising a side reflector portion.

23. The backlighting system as recited in claim 21, further comprising a diffuser disposed between the reflective cavity and the lightguide.

24. The backlighting system as recited in claim 23, wherein the diffuser comprises a rigid optically clear plate and a diffuser sheet attached thereto.

25. The backlighting system as recited in claim 20, wherein at least one light source disposed in the interior of the reflective cavity is an array of light sources.

26. The backlighting system as recited in claim 20, wherein at least one light source disposed in the interior of the reflective cavity is an extended light source.

27. The backlighting system as recited in claim 20, wherein at least one light source disposed in the interior of the reflective cavity is an array of linear light sources substantially parallel to each other.

28. The backlighting system as recited in claim 27, wherein the first edge of the lightguide is substantially orthogonal to the linear light sources.

29. The backlighting system as recited in claim 27, wherein the first edge of the lightguide is substantially parallel to the linear light sources.

30. The backlighting system as recited in claim 20, wherein the lightguide comprises surface structures disposed on a surface of the lightguide that faces the reflective cavity.

31. The backlighting system as recited in claim 30, wherein the surface structures include a plurality of prismatic structures substantially symmetrical about a horizontal axis.