LIGHT EMITTING DEVICES AND APPLICATIONS THEREOF

• US 20100321952A1
• Filed: 05/03/2010
• Published: 12/23/2010
• Est. Priority Date: 05/01/2009
• Status: Active Grant

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.), Fusion Optix Inc.
• Original Assignee: Massachusetts Development Finance Agency (STATE OF MASSACHUSETTS)
• Inventors: Morin, David, Ngai, Peter Yi Yan, Coleman, Zane, Tran, Michael Trung, Yeo, Terence
• Granted Patent: US 8,783,898 B2
• Time in Patent Office: Days
• US Class Current: 362/607
• CPC Class Codes: F21S 8/04 intended only for mounting on a ceiling or the like overhead structures F21S8/02 takes precedence; details of ceiling bases F21V21/03
• CPC Class Codes: F21S 8/06 by suspension
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0063 for extracting light out both the major surfaces of the light guide

Abstract

In one aspect, the present invention provides light emitting devices, including light fixtures and luminaires. In some embodiments, a light emitting device comprises at least one light source, a lightguide operable to receive light from the at least one light source at a first location on the lightguide, at least one light extraction region optically coupled to the lightguide and a substantially non-scattering region along a portion of the lightguide.

Claims

1. A light emitting device comprising:

at least one light source;

a lightguide operable to receive light from the at least one light source at a first location on the lightguide;

at least one light extraction region optically coupled to the lightguide, and

a substantially non-scattering region along a portion of the lightguide.

2. The light emitting device of claim 1, wherein the light guide is curved.

3. The light emitting device of claim 2, wherein the lightguide is a panel.

4. The light emitting device of claim 3, wherein the panel has a radius of curvature of at least about 7.5 inches.

5. The light emitting device of claim 1, wherein the lightguide has a width of at least about 0.5 inches.

6. The light emitting device of claim 5, wherein the lightguide has a length of at least about 1 inch.

7. The light emitting device of claim 1, comprising a plurality of light sources, wherein the lightguide is operable to receive light from the plurality of light sources at a plurality of locations on the lightguide.

8. The light emitting device of claim 7, wherein the plurality of locations are along at least a first edge of the lightguide.

9. The light emitting device of claim 7, wherein the plurality of locations are along at least a first edge and a second edge of the lightguide.

10. The light emitting device of claim 9, wherein the first edge and the second edge are in facing opposition.

11. The light emitting device of claim 1, wherein the substantially non-scattering region is disposed between the at least one light source and the at least one light extraction region.

12. The light emitting device of claim 7, wherein the substantially non-scattering region is disposed between the plurality of light sources and the at least one light extraction region.

13. The light emitting device of claim 9, wherein the substantially non-scattering region is disposed between the plurality of light sources and the at least one light extraction region.

14. The light emitting device of claim 1, wherein the substantially non-scattering region is visible to an observer of the light emitting device.

15. The light emitting device of claim 1, wherein the substantially non-scattering region has a haze according to ASTM D1003 less than 5%.

16. The light emitting device of claim 1, wherein the substantially non-scattering region has a clarity of greater than 95%.

17. The light emitting device of claim 1, wherein the at least one light extraction region is disposed between the light source and the substantially non-scattering region.

18. The light emitting device of claim 1, wherein the at least one light extraction region comprises a volumetric light scattering element, a surface relief light scattering element or a combination thereof.

19. The light emitting device of claim 18, wherein the volumetric light scattering element comprises light scattering phase domains or voids dispersed in a matrix.

20. The light emitting device of claim 18, wherein the volumetric light scattering element or the surface relief light scattering element isotropically scatters light received from the lightguide.

21. The light emitting device of claim 18, wherein the volumetric light scattering element or the surface relief light scattering element anisotropically scatters light received from the lightguide.

22. The light emitting device of claim 18, wherein the volumetric light scattering element or the surface relief light scattering element has a haze of greater than 50% according to ASTM D1003.

23. The light emitting device of claim 19, wherein the light scattering domains or voids have an asymmetric shape.

24. The light emitting device of claim 18, wherein the volumetric light scattering element has an angular full width at half maximum intensity when illuminated with collimated light in a first output plane of at least 5°

.

25. The light emitting device of claim 18, wherein the volumetric light scattering element has a first angular full width at half maximum intensity when illuminated with collimated in a first plane substantially the same as a second angular full width at half maximum intensity when illuminated with collimated light in a second plane normal to the first plane.

26. The light emitting device of claim 1 further comprising a light emitting region positioned to receive at least a portion of light extracted from the lightguide by the light extraction region.

27. The light emitting device of claim 26, wherein the light emitting region is in facing opposition to the light extraction region.

28. The light emitting device of claim 26, wherein the light emitting region comprises at least one optical element.

29. The light emitting device of claim 28, wherein the optical element comprises a lens.

30. The light emitting device of claim 28, wherein the optical element is a light redirecting optical element.

31. The light emitting device of claim 30, wherein the light redirecting optical element comprises a scattering element, a diffractive element, a refractive element, a reflective element, a re-emitting element, a holographic element or a combination thereof.

32. The light emitting device of claim 30, wherein the light redirecting element is a lenticular lens.

33. The light emitting device of claim 32, wherein the lenticular lens is a one-dimensional or a two-dimensional array of lens structures.

34. The light emitting device of claim 33, wherein the lens structures have one or more profiles or cross-sectional profiles selected from the group consisting of hemispherical, aspherical, arcuate, elliptical, conical, triangular, prismatic, rectangular and polygonal.

35. The light emitting device of claim 32, wherein the lenticular lens has a pitch of up to about 300 μ

m.

36. The light emitting device of claim 32, wherein the lenticular lens has a pitch of at least 100 μ

m.

37. The light emitting device of claim 33, wherein at least one of the lens structures has a radius of curvature up to about 500 μ

m.

38. The light emitting device of claim 33, wherein at least one of the lens structures has a sagittal depth of at least 5 μ

m.

39. The light emitting device of claim 30 having a ratio of luminous intensity at 40°

from nadir to luminous intensity at the nadir greater than or equal to 1.2.

40. The light emitting device of claim 30 having a luminous intensity at 55°

or greater from nadir less than or equal to 300 candelas.

41. The light emitting device of claim 30 having a luminous intensity at 65°

from nadir less than or equal to 220 candelas.

42. The light emitting device of claim 30 having a luminous intensity at 75°

from nadir less than or equal to 135 candelas.

43. The light emitting device of claim 30 having a luminous intensity at 85°

from nadir less than or equal to 45 candelas.

44. The light emitting device of claim 30 having a luminous intensity at 65°

from nadir less than or equal to 300 candelas.

45. The light emitting device of claim 30 having a luminous intensity at 75°

from nadir less than or equal to 185 candelas.

46. The light emitting device of claim 30 having a luminous intensity at 85°

from nadir less than or equal to 60 candelas.

47. The light emitting device of claim 30 having a ratio of peak luminance to luminance at nadir in a first output plane greater than or equal to 1.2.

48. The light emitting device of claim 30, having a ratio of luminance at 40°

from nadir to luminance at the nadir in a first output plane greater than or equal to 1.2.

49. The light emitting device of claim 26 having an angular luminance uniformity of the light emitting region greater than 40% over an angular range of 0°

to 55°

from nadir in a first output plane.

50. The light emitting device of claim 30, wherein the light emitting region has a spatial luminance uniformity of at least 50% at the angle of peak luminance.

51. The light emitting device of claim 26 further comprising at least one light blocking region at least partially covering a surface of the lightguide.

52. The light emitting device of claim 51 wherein the light blocking region is positioned between the light source and the light emitting region.

53. The light emitting device of claim 51, wherein the light blocking region comprises a reflector, a light absorbing material or a combination thereof.

54. The light emitting device of claim 51, wherein the light blocking region comprises a reflective metal frame, the metal frame comprising a recess operable to receive the lightguide.

55. The light emitting device of claim 54, wherein the light source is disposed within the recess.

56. The light emitting device of claim 55, further comprising a light absorbing material disposed between the lightguide and the reflective metal frame.

57. The light emitting device of claim 56, wherein the light absorbing material has d/8 diffuse reflectance less than 70%.

58. The light emitting device of claim 56, wherein the light absorbing material has a luminous transmittance measured according to ASTM D1003 less than 10%.

59. The light emitting device of claim 56, wherein the light absorbing material has a reflectance less than 20%.

60. The light emitting device of claim 51, wherein the light blocking region is not optically coupled to the lightguide.

61. The light emitting device of claim 60, wherein an airgap or low refractive index material is disposed between the light blocking region and the lightguide.

62. The light emitting device of claim 51, wherein the light blocking region is optically coupled to the lightguide.

63. A method of lighting a surface comprising:

providing a light emitting device comprising at least one light source, a lightguide operable to receive light from the at least one light source at a first location on the lightguide, at least one light extraction region optically coupled to the lightguide, a light emitting region and a substantially non-scattering region along a portion of the lightguide;

transmitting light from the light source into the into the lightguide;

extracting at least a portion of the light from the lightguide for emission from the light emitting device through the light emitting region.