Non-uniform diffuser to scatter light into uniform emission pattern

Patent metadata

Field	Value
Publication number	US-9310030-B2
Application number	US-90140510-A
Country	US
Kind code	B2
Filing date	Oct 8, 2010
Priority date	Mar 3, 2010
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

A lighting device comprising a light source and a diffuser spaced from the light source. The lighting device further comprises a wavelength conversion material disposed between the light source and the diffuser and spaced from the light source and the diffuser, wherein the diffuser is shaped such that there are different distances between the diffuser and said conversion material at different emission angles. In other embodiments the diffuser includes areas with different diffusing characteristics. Some lamps are arranged to meet A19 and Energy Star lighting standards.

First claim

We claim:

1. A lamp, comprising:
a solid state light source emitting a substantially forward emission pattern;
a diffuser to alter said forward emission pattern so that said lamp emits an emission pattern comprising greater uniformity than said forward emission pattern;
wherein the diffuser comprises a plurality of diffuser attributes that are used to control a desired emission profile for the lamp; and
wherein said diffuser comprises varying scattering properties over its surface based on the desired emission profile for the lamp.

2. The lamp of claim 1 , wherein said substantially forward emission pattern comprises a substantially Lambertian emission pattern.

3. The lamp of claim 1 , wherein said light source is substantially planar.

4. The lamp of claim 1 , wherein said substantially uniform emission pattern is substantially omnidirectional.

5. The lamp of claim 1 , wherein said diffuser comprises varying scattering properties along at least one dimension of the diffuser.

6. The lamp of claim 5 , wherein said varying scattering properties comprises varying scattering surface properties, or varying volume of scattering materials.

7. The lamp of claim 5 , wherein said varying scattering properties comprise higher diffuser scattering power in the axis of said light source emission comprising a higher light intensity, and lower diffuser scattering power in the axis of said light source emission comprising a lower light intensity.

8. The lamp of claim 1 , wherein said light source is a solid state light source.

9. The lamp of claim 1 , further comprising a wavelength conversion element in the light path between said light source and diffuser.

10. The lamp of claim 9 , wherein said conversion element comprises a transparent phosphor carrier.

11. The lamp of claim 9 , wherein said wavelength conversion element comprises a phosphor carrier comprising a transparent, thermally conductive material.

12. The lamp of claim 9 , wherein said conversion element is three-dimensional.

13. The lamp of claim 12 , wherein said conversion element is substantially rotationally symmetric.

14. The lamp of claim 12 , wherein said conversion element is a substantially linear diffuser dome.

15. The lamp claim 9 , wherein said conversion element is planar.

16. The lamp of claim 1 , wherein said diffuser comprises a diffuser dome.

17. The lamp of claim 1 , wherein said diffuser comprises a rotationally symmetric diffuser dome.

18. The lamp of claim 1 , wherein said diffuser comprises a substantially linear diffuser dome.

19. The lamp of claim 1 , wherein said diffuser comprises a diffusing material, wherein said diffuser comprises one or more areas covered by a greater amount of diffusing material.

20. The lamp of claim 1 , further comprising heat dissipation elements to conduct conversion heat away from said wavelength conversion material.

21. The lamp of claim 1 , wherein said light source comprises a plurality of co-planar light emitting diodes (LEDs).

22. The lamp of claim 1 , wherein the light emitted from the diffuser comprises a spatial uniformity that is within 40% of a mean value within a range of viewing angles.

23. The lamp of claim 1 , wherein the light emitted from the diffuser comprises a spatial uniformity that is within 20% of a mean value within a range of viewing angles.

24. A lamp, comprising:
a light source; and
an optical element at least partially covering said light source so that at least some light from said light source passes through said optical element, said optical element comprising scattering properties that vary along at least one dimension of the element to modify the emission distribution of the light emitted by said light source, said optical element comprising a plurality of diffuser attributes including said scattering properties, wherein said diffuser attributes are used to control a desired emission profile for the lamp.

25. The lamp of claim 24 , wherein said optical element modifies angular distribution of light emitted by said light source.

26. The lamp of claim 24 , wherein said light source emits light with a substantially non-uniform emission distribution, said optical element modifying said substantially non-uniform distribution to a substantially uniform distribution.

27. The lamp of claim 24 , wherein said light source emits a substantially Lambertian emission pattern, said optical element modifying said substantially Lambertian emission pattern to a substantially uniform emission pattern.

28. The lamp of claim 24 wherein said optical element comprises a diffuser comprising varying scattering properties.

29. The lamp of claim 28 , wherein said diffuser comprises varying scattering properties along one dimension of the diffuser.

30. The lamp of claim 24 , wherein said light source is a solid state light source.

31. The lamp of claim 24 , further comprising a wavelength conversion element in the light path between said light source and diffuser.

32. The lamp of claim 31 , wherein said conversion element comprises a phosphor carrier.

33. The lamp of claim 31 , wherein said conversion element is three-dimensional.

34. The lamp claim 31 , wherein said conversion element is planar.

35. The lamp of claim 31 , wherein said conversion element is substantially rotationally symmetric.

36. The lamp of claim 24 , wherein said optical element comprises a diffuser.

37. The lamp of claim 36 , wherein said diffuser is substantially rotationally symmetric.

38. The lamp of claim 24 , wherein the light emitted from the optical element comprises a spatial uniformity that is within 40% of a mean value within a range of viewing angles.

39. The lamp of claim 24 , wherein the light emitted from the optical element comprises a spatial uniformity that is within 20% of a mean value within a range of viewing angles.

40. The lamp of claim 24 , wherein said varying scattering properties comprise higher diffuser scattering power in the axis of said light source emission comprising a higher light intensity, and lower diffuser scattering power in the axis of said light source emission comprising a lower light intensity.

41. A lighting device comprising:
a light source;
a diffuser spaced from and in the light path of the light source; and
a wavelength conversion element between the light source and the diffuser and spaced from the light source and the diffuser, wherein said diffuser is shaped such that there are different distances between said diffuser and said conversion material at different emission angles;
wherein said diffuser comprises diffusing properties that vary across one or more areas of the diffuser based on the desired emission profile for the lighting device.

42. The lighting device of claim 41 , wherein said light source is a solid state light source.

43. The lighting device of claim 41 , wherein said wavelength conversion element comprises a phosphor carrier comprising a thermally conductive material.

44. The lighting device of claim 41 , wherein said diffuser comprises a diffuser dome.

45. The lighting

Assignees

• Tong Tao
• Letoquin Ronan
• Keller Bernd
• Tarsa Eric
• Youmans Mark
• Lowes Theodore
• Medendorp Jr Nicholas W
• Van De Ven Antony
• Negley Gerald
• Guschl Peter
• Yuan Zongjie
• Cree Inc

Inventors

• Tong Tao
• Letoquin Ronan
• Keller Bernd
• Tarsa Eric
• Youmans Mark
• Lowes Theodore
• Medendorp Jr Nicholas W
• Van De Ven Antony
• Negley Gerald
• Guschl Peter
• Yuan Zongjie

Classifications

• F21V5/10

  comprising photoluminescent material · CPC title

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• H10W74/00

  Encapsulations, e.g. protective coatings · CPC title

• H10W72/884

  Die-attach connectors and bond wires · CPC title

• F21K9/60

  Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction · CPC title