Axial LED source

• US 7,048,412 B2
• Filed: 06/10/2002
• Issued: 05/23/2006
• Est. Priority Date: 06/10/2002
• Status: Expired due to Fees

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Martin, Paul S., Steigerwald, Daniel A., West, R. Scott
• Primary Examiner(s): Alavi, Ali
• Application Number:
  US10/166,853
• Publication Number:
  US 20030227774A1
• Time in Patent Office: 1,443 Days
• Field of Search: 362/507, 362/510, 362516-517, 362543-545, 362235-240, 362/241, 362/247, 362/245, 362/348, 362/215
• US Class Current: 362/247
• CPC Class Codes: F21K 9/68 Details of reflectors forming part of the light source
• CPC Class Codes: F21S 41/148 the main emission direction of the LED being perpendicular to the optical axis
• CPC Class Codes: F21S 41/151 arranged in one or more lines
• CPC Class Codes: F21S 41/335 with continuity at the junction between adjacent areas
• CPC Class Codes: F21S 45/47 Passive cooling, e.g. using fins, thermal conductive elements or openings
• CPC Class Codes: F21V 29/51 using condensation or evaporation of a fluid, e.g. heat pipes
• CPC Class Codes: F21V 29/77 with essentially identical diverging planar fins or blades, e.g. with fan-like or star-like cross-section
• CPC Class Codes: F21V 7/09 with a combination of different curvatures
• CPC Class Codes: F21Y 2101/00 Point-like light sources
• CPC Class Codes: F21Y 2107/30 on the outer surface of cylindrical surfaces, e.g. rod-shaped supports having a circular or a polygonal cross section
• CPC Class Codes: F21Y 2107/40 on the sides of polyhedrons, e.g. cubes or pyramids
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A lamp has LED sources that are placed about a lamp axis in an axial arrangement. The lamp includes a post with post facets where the LED sources are mounted. The lamp includes a segmented reflector for guiding light from the LED sources. The segmented reflector includes reflective segments each of which is illuminated primarily by light from one of the post facets (e.g., one of the LED sources on the post facet). The LED sources may be made up of one or more LED dies. The LED dies may include optic-on-chip lenses to direct the light from each post facet to a corresponding reflective segment. The LED dies may be of different sizes and colors chosen to generate a particular far-field pattern.

Claims

1. A lamp, comprising:

a post aligned along a lamp axis;

a plurality of LED sources mounted on the post, wherein normal vectors to light emitting surfaces of the LED sources are approximately perpendicular to the lamp axis; and

a reflector for guiding light primarily along the lamp axis, wherein the reflector is comprises reflective segments each optimized for a different LED source, so that each LED source primarily illuminates a different reflective segment.

2. The lamp of claim 1, wherein the post has an incrementing cross- section along its length toward a base of the lamp to conduct heat away from the LED sources and to the base.

3. The lamp of claim 2, wherein the post comprises a cone, a stepped, or a pyramid shape.

4. The lamp of claim 1, wherein the post comprises a triangular, rectangular, pentagonal, or hexagonal cross-section along its length.

5. The lamp of claim 1, wherein the reflective segments each comprises a focus located at a different LED source.

6. The lamp of claim 1, wherein the LED sources each comprises a monolithic LED die with an array LEDs, an array of individual LEDs, or an individual LED.

7. The lamp of claim 6, wherein each LED includes an optic-on-chip lens atop of its light emitting surface to control its solid angle of light emission so each LED primarily emits ligt onto only one of the reflective segments.

8. The lamp of claim 6, wherein the LED sources comprise LEDs of different sizes.

9. The lamp of claim 7, wherein the post has a decrementing cross-section along its length toward a base of the lamp so the LED sources are angled from the lamp axis.

10. The lamp of claim 9, wherein the post comprises an inverted cone, an inverted stepped shape, or an inverted pyramid shape.

11. The lamp of claim 9, wherein the post comprises curved post facets.

12. The lamp of claim 1, wherein the post includes an axial heat pipe along its length to conduct heat away from the LED sources and to a base of the lamp.

13. The lamp of claim 12, further comprising a heat sink coupled to the axial heat pipe.

14. The lamp of claim 13, wherein the heat sink comprises a plurality of fins coupled to the axial heat pipe.

15. The lamp of claim 12, further comprising a lateral heat pipe coupled to the axial heat pipe.

16. The lamp of claim 15, wherein the axial heat pipe has a screw base and the lateral heat pipe has a threaded bore for receiving the screw base.

17. The lamp of claim 12, wherein the axial heat pipe has an incrementing cross-section along its length toward the base of the lamp.

18. The lamp of claim 1, wherein each the LED sources each comprises an array of individual LEDs of different colors.

19. The lamp of claim 18 wherein the reflector mixes the different colors to project a far-field pattern that includes white light.

20. The lamp of claim 18, wherein the reflector partially mixes the different colors.

21. The lamp of claim 18, wherein the LEDs of the same color on at least two different LED sources are not placed in the same relative position along the post.

22. The lamp of claim 1, wherein the reflector projects light from different LED sources into non-overlapping parts of a far-field pattern.

23. The lamp of claim 1, wherein the reflector projects light from different LED sources to overlay each other in a far-field pattern.

24. The lamp of claim 1, wherein the LED sources are of different colors and the reflector at least partially mixes different colors of the LED sources to project a far-field pattern.

25. The lamp of claim 1, wherein the LED sources are of different colors and the reflector does not mix the different colors of the LED sources to project a far-field.

26. The lamp of claim 1, further comprising an optical structure on the post to direct light from one of the LED sources to one of the reflector segments.

27. The lamp of claim 26, wherein the optical structure comprises a first reflector and a second reflector on the post.

28. A method for generating a far-field pattern with a lamp having a plurality of LED sources on a post aligned with a lamp axis and a reflector including reflective segments each optimized for a different LED source so that each LED source primarily illuminates a different reflective segment the method comprising:

independently controlling (1) a first LED source and (2) a second LED source to generate the far-field pattern.

29. The method of claim 28, wherein said independently controlling comprises:

independently changing current levels to (1) the first LED source and (2) the second LED source to shape the far-field pattern.

30. The method of claim 28, whrein the first LED source and the second LED source generate at least partially overlapping patterns in the far-field pattern.

31. The method of claim 28, wherein the first LED source and the second LED source generate non-overlapping patterns in the far-field pattern.

32. The method of claim 28, wherein the first LED and the second LED are of different sizes.

33. The method of claim 28, wherein the far-field pattern is at least a part of a low beam pattern, a high beam pattern, a spread light pattern, or a sign light pattern.

34. The method of claim 28, wherein the far-field pattern is at least a part of a beam pattern, a high beam patttern, a spread light pattern, or a sight light pattern.

35. The method of claim 28, wherein the first LED source and the second LED source generate lights of different colors.

36. The method of claim 35, wherein said independently controling comprises:

independently changing current levels to (1) the first LED source and (2) the second LED source to generate the far-field pattern including a desired color.

37. The method of claim 36, wherein the first LED source and the second LED source generate overlapping patterns in the far-field pattern.

38. The method of claim 36, wherein the first LED source and the second LED source generate non-overlapping patterns in the far-field pattern.

39. The method of claim 28, wherein the first LED source comprises a first LED and a second LED of different colors.

40. The method of claim 39, wherein said independent controlling comprises changing current levels to the first LED source and the second LED source.