Apparatus and method for using emitting diodes (LED) in a side-emitting device

• US 20050083699A1
• Filed: 08/11/2004
• Published: 04/21/2005
• Est. Priority Date: 08/12/2003
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Greg Rhoads, Ronald Garrison Holder
• Inventors: Rhoads, Greg, Holder, Ronald Garrison
• Granted Patent: US 7,246,917 B2
• Time in Patent Office: Days
• US Class Current: 362/296.70
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21V 7/0025 Combination of two or more reflectors for a single light source array of reflectors for a cluster of light sources F21V7/0083
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

An LED having a predetermined direction of radiation is combined with a first and second reflector. The first reflector opposes the LED and has a predetermined direction of reflection. The direction of reflection of the first reflector opposes the direction of radiation of the LED. The second reflector has a predetermined azimuthal direction of reflection. The second reflector positioned relative to the first reflector to receive light from the first reflector and redirect the light into the azimuthal direction of reflection. The LED, first and second reflectors collectively comprise an illumination unit. A plurality of illumination units are axially stacked. In one embodiment of the stack, at least one illumination unit comprises an LED and second reflector of one illumination unit and a first reflector of an adjacent illumination unit in the stack of illumination units.

Claims

1. An apparatus comprising:

an LED light source having a predetermined direction of radiation;

a first reflector opposing the LED light source having a predetermined direction of reflection, the direction of reflection of the first reflector opposing the direction of radiation of the LED light source; and

a second reflector having a predetermined azimuthal direction of reflection, the second reflector positioned relative to the first reflector to receive light from the first reflector and to redirect the light into the azimuthal direction of reflection.

2. The apparatus of claim 1 where the first reflector comprises a generally concave reflector.

3. The apparatus of claim 2 where the concave reflector comprises a parabolic reflector.

4. The apparatus of claim 1 where the second reflector comprises a generally conical reflector.

5. The apparatus of claim 2 where the second reflector comprises a generally conical reflector.

6. The apparatus of claim 1 where the LED light source, first and second reflectors each have an optical axis and where the optical axis of each are mutually aligned.

7. The apparatus of claim 1 further comprising a heat sink thermally coupled to the LED light source.

8. The apparatus of claim 7 where the heat sink positions the LED light source within the apparatus.

9. The apparatus of claim 7 where the heat sink comprises a hub coupled to the LED light source, at least one radially extending arm thermally coupled to the hub and a body thermally coupled to the arm.

10. The apparatus of claim 1 where the second reflector is coupled to the LED light source, is comprised of a thermally conductive material, and acts as a heat sink for the LED light source.

11. The apparatus of claim 1 where the LED light source, first and second reflectors collectively comprise an illumination unit and further comprising a plurality of illumination units axially arranged and configured with respect to each other to provide a stack of illumination units.

12. The apparatus of claim 11 where at least one illumination unit in the stack of illumination units comprises an LED light source and second reflector of one illumination unit and a first reflector of an adjacent illumination unit in the stack of illumination units.

13. The apparatus of claim 12 where the first and second reflectors comprise separate bodies.

14. The apparatus of claim 12 where the first and second reflectors comprise a common body with two surfaces, one surface providing the first reflector and the other surface providing the second reflector.

15. The apparatus of claim 12 where the stack of illumination units further comprises a first end element comprised of the first reflector and a second end element comprised of an LED light source and the second reflector.

16. The apparatus of claim 1 where the second reflector is arranged and configured to project central rays of light in an azimuthal pattern reflected from the first reflector and to project field rays of light in an azimuthal pattern reflected from the first reflector.

17. The apparatus of claim 16 where the LED light source, first and second reflectors are arranged and configured to provide a selected ratio of light intensity in the central rays to the field rays.

18. The apparatus of claim 16 where the LED light source, first and second reflectors are arranged and configured to provide the field rays with a selected degree of divergence.

19. The apparatus of claim 16 where the LED light source, first and second reflectors are arranged and configured to provide a beam of light in a 360 degree azimuthal pattern.

20. The apparatus of claim 1 further comprising a cylindrical transparent body azimuthally surrounding the second reflector through which the redirected light is transmitted.

21. The apparatus of claim 20 where the cylindrical body comprises a color filter.

22. The apparatus of claim 1 where the LED light source comprises an LED light source having a selected color of radiated light.

23. The apparatus of claim 11 where each of the LED light sources in the stack comprises an LED light source having a selected color of radiated light with at least two of the selected colors being different from each other.

24. A method comprising:

generating light from an LED light source in a predetermined direction of radiation;

reflecting light from a first reflector opposing the LED light source in a predetermined direction of reflection, the direction of reflection opposing the direction of radiation of the LED light source; and

reflecting light from a second reflector having a predetermined azimuthal direction of reflection, the second reflector positioned relative to the first reflector to receive light from the first reflector and to redirect the light into the azimuthal direction of reflection.

25. The method of claim 24 where reflecting light from the first reflector comprises a reflecting light from a generally concave reflector.

26. The method of claim 25 where reflecting light from the concave reflector comprises reflecting light from a parabolic reflector.

27. The method of claim 24 where reflecting light from the second reflector comprises reflecting light from a generally conical reflector.

28. The method of claim 25 where reflecting light from the second reflector comprises reflecting light from a generally conical reflector.

29. The method of claim 24 further comprising positioning the LED light source relative to the first and second reflectors using a thermal heat sink mechanically and thermally coupled to the LED light source.

30. The method of claim 29 where positioning the LED light source relative to the first and second reflectors using a thermal heat sink comprises using the second reflector as the heat sink.

31. The method of claim 24 further comprising combining the LED light source, first and second reflectors collectively as an illumination unit and axially stacking a plurality of illumination units.

32. The method of claim 31 where axially stacking a plurality of illumination units comprises employing an LED light source and second reflector of one illumination unit and a first reflector of an adjacent illumination unit as a replicated combination in the stack.

33. The method of claim 32 where employing an LED light source and second reflector of one illumination unit and a first reflector of an adjacent illumination unit comprises providing the first and second reflectors comprise separate bodies.

34. The method of claim 32 where employing an LED light source and second reflector of one illumination unit and a first reflector of an adjacent illumination unit comprises providing the first and second reflectors on a common body with two surfaces, one surface providing the first reflector and the other surface providing the second reflector.

35. The method of claim 32 further comprising providing a first end element of the stack comprised of the first reflector, and a second end element of the stack comprised of an LED light source and the second reflector.

36. The method of claim 24 where reflecting light from the second reflector projects central rays of light in an azimuthal pattern reflected from the first reflector and projects field rays of light in an azimuthal pattern reflected from the first reflector.

37. The method of claim 36 where reflecting light from the second reflector comprises projecting a selected ratio of light intensity in the central rays to the field rays.

38. The method of claim 36 where reflecting light from the second reflector comprises projecting the field rays with a selected degree of divergence.

40. The method of claim 36 where reflecting light from the second reflector comprises projecting a beam of light in a 360 degree azimuthal pattern.

41. The method of claim 24 further comprising a projecting light through a cylindrical transparent body azimuthally surrounding the second reflector.

42. The method of claim 41 where projecting light through the cylindrical transparent body comprises projecting light through a color filter.

43. The method of claim 24 where generating light from the LED light source comprises generating light in a selected color.

44. The method of claim 31 where generating light from the stack comprises generating at least two of the selected colors different from each other from different LED light sources.