Side emitting light emitting device

• US 6,598,998 B2
• Filed: 05/04/2001
• Issued: 07/29/2003
• Est. Priority Date: 05/04/2001
• Status: Expired due to Term

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: West, Robert S., Sasser, Gary D., Stewart, James W.
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Alavi, Ali
• Application Number:
  US09/849,042
• Publication Number:
  US 20020163810A1
• Time in Patent Office: 816 Days
• Field of Search: 362/307, 362/308, 362/309, 362/326, 362/327, 362/328, 362/329, 362/31, 362/800, 362/556, 362/555, 362/582, 313/500, 313/512
• US Class Current: 362/307
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 19/0071 adapted to illuminate a complete hemisphere or a plane extending 360 degrees around the source
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A lens mounted to a light emitting diode package internally redirects light within the lens so that a majority of light is emitted from the lens approximately perpendicular to a package axis of the light emitting diode package. In one embodiment, the light emitted by the light emitting diode package is refracted by a sawtooth portion of the lens and reflected by a total internal reflection portion of the lens.

Claims

1. A light-emitting device comprising:

a light-emitting semiconductor device; and

a lens comprising;

a bottom surface;

a reflecting surface; and

a refracting surface obliquely angled with respect to a central axis of the lens;

wherein light emitted by the semiconductor device, entering the lens through the bottom surface, and directly incident on the reflecting surface is reflected from the reflecting surface to the refracting surface and refracted by the refracting surface to exit the lens in a direction substantially perpendicular to the central axis of the lens.

2. The device of claim 1, wherein the lens is diamond turned.

3. The device of claim 1, wherein the lens is injection molded.

4. The device of claim 1, wherein the lens is cast.

5. The device of claim 1, wherein the lens is made of a transparent material.

6. The device of claim 1, wherein the lens is colored.

7. The device of claim 1, wherein the light-emitting semiconductor device is disposed in a package, and wherein the lens is bonded to the package.

8. The device of claim 1, wherein the light-emitting semiconductor device is disposed in a package, and wherein the lens is snap-fit to the package.

9. The light-emitting device of claim 1, wherein the bottom surface of the lens is perpendicular to the central axis of the tens.

10. The device of claim 1, wherein the light-emitting semiconductor device is disposed in a package, and wherein the lens is heat staked to the package.

11. The device of claim 1, wherein the light-emitting semiconductor device is disposed in a package, and wherein the lens is ultra-sonically welded to the package.

12. The device of claim 1, wherein the lens has an index of refraction in the range of approximately 1.45 to 1.6.

13. The device of claim 1, wherein the lens has an index of refraction of approximately 1.53.

14. The device of claim 1, wherein the lens is made of a material selected from the group consisting of PC, PMMA, PEI, Pc/PMMA and COC.

15. The light-emitting device of claim 1, wherein the reflecting surface reflects by total internal reflection.

16. The device of claim 1, wherein the refractive surface further comprises:

a sawtooth lens portion whereby the sawtooth lens portion refracts light entering the sawtooth lens portion such that a majority of light emitted from the sawtooth lens portion is generally perpendicular to the central axis of the lens.

17. The device of claim 1, wherein the reflective surface further comprises:

a funnel-shaped lens portion whereby the funnel-shaped lens portion reflects light entering the funnel-shaped lens portion such that a majority of light emitted from the funnel-shaped lens portion is generally perpendicular to the central axis of the lens.

18. The device of claim 17, wherein a surface of said funnel-shaped lens portion curves away from the central axis of the lens.

19. The device of claim 17, wherein a surface of said funnel-shaped lens portion includes at least two linear portions angled with respect to each other and the central axis of the lens.

20. The device of claim 17, wherein a surface of said funnel-shaped lens portion is a straight line at an angle with respect to the central axis of the lens.

21. The device of claim 1, wherein the refractive surface further comprises a sawtooth lens portion;

and the reflective surface further comprises a funnel-shaped lens portion whereby the sawtooth and funnel-shaped lens each direct light entering the sawtooth and funnel-shaped lens portions such that a majority of light emitted from each of the sawtooth and funnel-shaped lens portions is generally perpendicular to the central axis of the lens.

22. The device of claim 1, wherein there is a sealed space between the light-emitting semiconductor device and the lens.

23. The device of claim 1, wherein there is a sealed space filled with a resin between the light-emitting semiconductor device and the lens.

24. The device of claim 23, wherein the resin is optically transparent.

25. The device of claim 23, wherein the resin is silicone.

26. The device of claim 1, further comprising a sealed space between the light-emitting semiconductor device and the lens wherein the sealed space is filled with an epoxy.

27. The device of claim 1, wherein there is a sealed space filled with an optically transparent material between the light-emitting semiconductor device and the lens.

28. The device of claim 1, wherein there is a sealed space filled with a material with an index of refraction ranging approximately between 1.4 to 1.6 located between the light-emitting semiconductor device and the lens.

29. The device of claim 1, further comprising:

a light guide whereby light emitted from the lens enters the light guide.

30. The device of claim 29, wherein the lens is mounted along the perimeter of the light guide.

31. The device of claim 29, wherein the lens is mounted within at least one hole in the light guide.

32. The device of claim 31, wherein said hole further comprises an inner surface roughly parallel to a first surface of the lens.

33. The device of claim 32, wherein the inner surface is linear.

34. The device of claim 32, wherein the inner surface is funnel-shaped.

35. The device of claim 32, wherein the inner surface is V-shaped.

36. The device of claim 29, wherein the light guide is made a material selected from the group consisting of PC and PMMA.

37. The device of claim 29, wherein the light guide ranges in thickness from approximately 2 to 8 mm.

38. The device of claim 29, wherein the light guide has a thickness greater than a length of the lens.

39. The device of claim 29, wherein the light guide has a thickness less than a length of the lens.

40. The device of claim 29, wherein the light guide has a thickness at least equal to a length of the lens.

41. The device of claim 31, wherein the hole in the light guide has a depth approximately equal to a length of the lens.

42. The device of claim 31, wherein the hole in the light guide has a depth less than a length of the lens.

43. The device of claim 31, wherein the hole in the light guide has a depth greater than a length of the lens.

44. The device of claim 29, wherein the light-emitting semiconductor device is located at a center of the light guide.

45. The device of claim 29, wherein a surface finish is applied to the light guide whereby the surface finish reflects light.

46. The device of claim 29, wherein a surface coating is applied to the light guide whereby the surface coating reflects light.

47. The device of claim 1, further comprising:

a reflector mounted to the light-emitting semiconductor device whereby the light emitted from the lens is redirected by the reflector to an intended target.

48. The device of claim 47, wherein the intended target is substantially perpendicular to the central axis of the lens.

49. The device of claim 47, wherein the light-emitting semiconductor device is mounted within at least one hole in the reflector.

50. The device of claim 47, wherein a height of the reflector is less than or equal to a length of the lens.

51. The device of claim 47, wherein a height of the reflector is greater than or equal to a length of the lens.

52. The device of claim 47, wherein a height of the reflector is approximately equal to a length of the lens.

53. The device of claim 47, wherein a surface coating is applied to the reflector.

54. The light-emitting device of claim 1, wherein the reflecting surface is a surface of a funnel-shaped portion of the lens.

55. The light-emitting device of claim 1, wherein the lens further comprises a second refracting surface and light emitted by the semiconductor device, entering the lens through the bottom surface, and directly incident on the second refracting surface is refracted by the second refracting surface to exit the lens in a direction substantially perpendicular to the central axis.

56. The light-emitting device of claim 1, wherein the second refractive surface is a surface of a saw tooth portion of the lens.

57. The light-emitting device of claim 1, wherein the reflecting and refracting surfaces of the lens are each portions of surfaces having cylindrical symmetry about the central axis.

58. The device of claim 1, further comprising a sealed space between the light-emitting semiconductor device and the lens wherein the sealed space is filled with a transparent material.

59. The device of claim 58, wherein the transparent material is colored.

60. The device of claim 1, wherein there is substantially no light emitted from the lens along the central axis of the lens.

61. A method of emitting light from a light emitting diode, comprising:

generating a light output from a light emitting diode package, said package containing a light emitting diode for emitting light; and

redirecting light from the light emitting diode using a lens comprising a bottom surface, a reflecting surface, and a refracting surface obliquely angled with respect to a central axis of the lens, wherein redirecting light from the light emitting diode comprises;

receiving light through the bottom surface;

refracting light incident on the refracting surface such that the refracted light exits the lens in a direction substantially perpendicular to the central axis of the lens; and

reflecting light incident on the reflecting surface such that the reflected light exits the lens in a direction substantially perpendicular to the central axis of the lens.

62. The method of claim 61, wherein:

the refracting surface comprises a sawtooth portion of the lens whereby the sawtooth portion refracts light such that a majority of light emitted from the sawtooth portion is substantially perpendicular to the central axis of the lens.

63. The method of claim 61, wherein:

the reflecting surface comprises a funnel-shaped portion of the lens whereby the funnel-shaped portion reflects light such that a majority of light emitted from the funnel-shaped portion is substantially perpendicular to the central axis of the lens.