Axial LED source

• US 20030227774A1
• Filed: 06/10/2002
• Published: 12/11/2003
• Est. Priority Date: 06/10/2002
• Status: Active Grant

• 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
• Granted Patent: US 7,048,412 B2
• Time in Patent Office: Days
• US Class Current: 362/240
• 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, the post comprising a post facet; and

a monolithic LED die mounted on the post facet, wherein the monolithic LED die includes an array of LEDs and normal vectors to light emitting surfaces of the LEDs are approximately perpendicular to the lamp axis.

2. The lamp of claim 1, further comprising a reflector for guiding light generally along the lamp axis, the reflector comprising a plurality of reflective segments and one reflective segment is illuminated primarily by light from the post facet.

3. The lamp of claim 2, wherein each of the LEDs includes an optic-on-chip lens atop of its light emitting surface to control its solid angle of light emission so each of the LEDs primarily emits light onto said one reflective segment.

4. A lamp, comprising:

a post aligned along a lamp axis, the post comprising a plurality of post facets;

a plurality of LED sources each mounted on one of the post facets, 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 divided into reflective segments each illuminated primarily by light from one of the post facets.

5. The lamp of claim 4, wherein the reflective segments each comprises a focus located at one of the LED sources.

6. The lamp of claim 4, wherein the LED sources each comprises a monolithic LED die with an array of 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 light onto one of the reflective segments.

8. 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.

9. The lamp of claim 8, wherein the post comprises an inverted cone, an inverted stepped, or an inverted pyramid shape.

10. The lamp of claim 8, wherein one of the post facets is curved.

11. The lamp of claim 6, 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.

12. The lamp of claim 6, 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.

13. The lamp of claim 12, wherein the post comprises a cone, a stepped, or a pyramid shape.

14. The lamp of claim 6, wherein the post comprises a triangular, rectangular, pentagonal, or hexagonal cross-section along its length.

15. The lamp of claim 4, wherein the LED sources each comprises an array of individual LEDs of different colors.

16. The lamp of claim 15, wherein the reflector mixes different colors of the LEDs to project a far-field pattern that includes white light.

17. The lamp of claim 15, wherein the reflector partially mixes different colors of the LEDs.

18. The lamp of claim 4, 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.

19. The lamp of claim 17, 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.

20. The lamp of claim 15, wherein the LEDs of the same color on at least two different post facets are not placed in the same relative position along the post facet.

21. The lamp of claim 6, wherein the LED sources on different post facets comprise LEDs of different sizes.

22. The lamp of claim 4, wherein the reflector projects light from different post facets into non-overlapping parts of a far-field pattern.

23. The lamp of claim 4, wherein the reflector projects light from different post facets to overlay each other in a far-field pattern.

24. The lamp of claim 4, further comprising an optical structure on the post to direct light from one of the post facets to one of the reflector segments.

25. The lamp of claims 24, wherein the optical structure comprises a first reflector and a second reflector on the post.

26. The lamp of claim 11, further comprising a heat sink coupled to the axial heat pipe.

27. The lamp of claim 26, wherein the heat sink comprises a plurality of fins coupled to the axial heat pipe.

28. The lamp of claim 11, further comprising a lateral heat pipe coupled to the axial heat pipe.

29. The lamp of claim 28, wherein the axial heat pipe has a screw base and the lateral heat pipe has a threaded bore for receiving the screw base.

30. The lamp of claim 11, wherein the axial heat pipe has an incrementing cross-section along its length toward the base of the lamp.

31. A lamp, comprising:

a post aligned along a lamp axis, the post comprising a post facet; and

an LED source mounted on the post facet, the LED source comprising an optic-on-chip lens mounted on a light emitting surface of the LED source, wherein a normal vector to the light emitting surface is approximately perpendicular to the lamp axis.

32. The lamp of claim 31, wherein the LED source comprises a monolithic LED die with an array of LEDs, an array of individual LEDs, or an individual LED.

33. The lamp of claim 32, further comprising an optical element for guiding light primarily along the lamp axis, the optical element comprising a plurality of surfaces and one surface is illuminated primarily by light from the post facet.

34. A method for generating a far-field pattern with a lamp having a plurality of LED sources on post facets of a post aligned with a lamp axis and a reflector including reflective segments each illuminated primarily by light from one of the post facets, comprising:

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

35. The method of claim 34, 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.

36. The method of claim 34, wherein the first LED source and the second LED source generate at least partially overlapping patterns in the far-field pattern.

37. The method of claim 34, wherein the first LED source and the second LED source generate non-overlapping patterns in the far-field pattern.

38. The method of claim 34, wherein the first LED source and the second LED source generate lights of different colors.

39. The method of claim 38, wherein said independently controlling 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.

40. The method of claim 34, wherein the first LED and the second LED are of different sizes.

41. The method of claim 34, 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.

42. The method of claim 34, wherein the far-field pattern is at least a part of a narrow flood light pattern or a wide flood light pattern.

43. The method of claim 39, wherein the first LED source and the second LED source generate overlapping patterns in the far-field pattern.

44. The method of claim 39, wherein the first LED source and the second LED source generate non-overlapping patterns in the far-field pattern.

45. The method of claim 34, wherein the first LED source comprises a first LED and a second LED of different colors.

46. The method of claim 45, wherein said independent controlling comprises changing current levels to the first LED source and the second LED source.