LIGHT TRANSMISSION CONTROL FOR MASKING APPEARANCE OF SOLID STATE LIGHT SOURCES

• US 20120018754A1
• Filed: 07/23/2010
• Published: 01/26/2012
• Est. Priority Date: 07/23/2010
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: LOWES, THEODORE DOUGLAS
• Granted Patent: US 10,546,846 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 14/00 Controlling the distribution of the light emitted by adjustment of elements reflectors with provision for adjusting the curvature F21V7/16; light filters or the like with provision for controlling the colour or intensity F21V9/40; screens using adjustable parallel laminae or strips F21V11/04; screens using iris-type diaphragms F21V11/10; screens using movable sheets without apertures F21V11/18; adjustable mountings for lighting devices F21V21/14
• CPC Class Codes: F21V 14/003 by interposition of elements with electrically controlled variable light transmissivity, e.g. liquid crystal elements or electrochromic devices
• CPC Class Codes: F21V 29/505 of reflectors
• CPC Class Codes: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 29/89 Metals
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21V 3/12 the coatings comprising photoluminescent substances
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02F 1/0147 based on thermo-optic effects G02F1/132 takes precedence
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/13718 based on a change of the texture state of a cholesteric liquid crystal
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 33/44 : characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/50 : Wavelength conversion elements

Abstract

A light emitter device, package, or lamp that comprises and light emitter and a light transmission control material to mask the appearance of at least the light emitter. In one embodiment, a light emitting diode (LED) based lamp is disclosed, comprising an LED light source. A phosphor is arranged remote to the light source such that light emitted from the light source passes through this phosphor and is converted by this phosphor. A light transmission control material is applied at least partially outside the LED light source and the phosphor to reversibly mask the appearance of the LED light source and the phosphor. The light transmission control material is less masking when the LED light source is active. A method for masking the appearance of inactive light emitters is also disclosed that comprising providing at least one light emitter. Each of the at least one light emitters is provided with a light transmission control material over the light emitters to reversibly mask the appearance of the light emitters while the light emitters are inactive. The light transmission control material is less masking when the LED light source is active.

Claims

1. A light emitting diode (LED) chip, comprising:

an LED; and

a coating at least partially covering said LED, said coating masking the appearance of said at least partially covered LED when said LED is inactive, and wherein said coating is less masking when said LED is active.

2. The LED chip of claim 1, wherein said coating becomes less masking in response to thermal changes.

3. The LED chip of claim 1, wherein said coating becomes less masking in response to an increase in temperature.

4. The LED chip of claim 3, wherein said coating is thermally coupled to said LED chip.

5. The LED chip of claim 1, wherein said coating becomes less masking in response to an electrical signal.

6. The LED chip of claim 5, wherein said coating is electrically coupled to said LED chip.

7. The LED chip of claim 1, wherein said coating comprises a polymer.

8. The LED chip of claim 2, wherein said coating causes less than 4% emission loss when said LED is active.

9. The LED chip of claim 1, wherein said coating becomes less masking in response to an optical stimulus.

10. A light emitting diode (LED) package comprising:

an LED chip;

package leads electrically connected to said LED chip;

encapsulation surrounding said LED chip and electrical connections; and

a light transmission control material at least partially covering said LED chip, wherein said light transmission control material masks said LED chip when said LED chip is inactive, and transmits at least some LED light when said LED chip is active.

11. The LED package of claim 10, wherein said light transmission control material is included within a coating at least partially on said encapsulation.

12. The LED package of claim 10, wherein said light transmission control material is within said encapsulation.

13. The LED package of claim 10, wherein said light transmission control material is less masking when said LED chip is active.

14. The LED package of claim 13, wherein said light transmission control material causes at most 4% emission loss when said LED chip is active.

15. The LED package of claim 10, wherein said light transmission control material changes from masking to transmitting in response to thermal changes.

16. The LED package of claim 15, wherein said light transmission control material is thermally coupled to said LED chip.

17. The LED package of claim 16, wherein said thermal coupling includes a conductive material in thermal contact with the light transmission control material.

18. The LED package of claim 17, wherein said conductive material is transparent.

19. The LED package of claim 10, wherein said light transmission control material changes from masking to light transmitting in response to an electrical signal.

20. The LED package of claim 19, wherein said light transmission control material is electrically coupled to said LED chip.

21. The LED package of claim 20, wherein said light transmission control material is electrically coupled to said LED chip using a transparent electrode.

22. The LED package of claim 10, wherein said light transmission control material changes from masking to light transmitting in response to light.

23. The LED package of claim 10, wherein said light transmission control material is applied to said encapsulation by molding.

31. The LED based lamp of claim 22, wherein said light transmission control material changes from masking to light transmitting in response to changes in temperature.

32. The LED based lamp of claim 31, wherein said light transmission control material is thermally coupled to said LED light source.

24. A light emitting diode (LED) based lamp, comprising:

an LED light source;

a phosphor arranged remote to said light source such that light emitted from said light source passes through said phosphor and is converted by said phosphor; and

a light transmission control material applied at least partially over said LED light source and said phosphor to mask the appearance of said LED light source and/or said phosphor when said LED is active and to transmit at least some of said light from said LED and/or said phosphor when said LED is active.

25. The LED based lamp of claim 24, wherein said light transmission control material comprises a coating at least partially on said phosphor.

26. The LED based lamp of claim 24, further comprising a cover over said LED light source and said phosphor.

27. The LED based lamp of claim 26, wherein said cover is coated with said light transmission control material.

28. The LED based lamp of claim 26, wherein said cover is comprised of said light transmission control material.

29. The LED based lamp of claim 24, wherein said light transmission control material is less masking when said LED light source is active.

30. The LED based lamp of claim 29, wherein said light transmission control material allows at least 96% of light emission when said LED light source is active.

33. The LED based lamp of claim 24, wherein said light transmission control material changes from masking to light transmitting in response to electricity.

34. The LED based lamp of claim 33, wherein said light transmission control material is electrically coupled to said LED light source.

35. The LED package of claim 24, wherein said light transmission control material is applied to said encapsulation by compression molding.

36. The LED package of claim 26, wherein said cover disperses light in a desired pattern.

37. The LED based lamp of claim 24, wherein said light transmission control material changes from masking to light transmitting in response to optical stimulus.

38. A method for masking the appearance of inactive light emitters, comprising;

providing at least one light emitter; and

providing a light transmission control material over said at least one light emitter to reversibly mask the appearance of said at least one light emitter while said at least one light emitter is inactive.

39. The method of claim 38, wherein said light transmission control material is less masking when said at least one light emitter is active.

40. The method of claim 39, wherein said light transmission control material allows at least 96% of light emission when said at least one light emitter is active.

41. The method of claim 38 further comprising providing an encapsulant over said light emitter.

42. The method of claim 41, wherein said providing of said light transmission control material comprises applying said light transmission control material as a coating over said encapsulant.

43. The method of claim 41, wherein said providing of said light transmission control material comprises applying said light transmission control material over said encapsulant by compression molding.

44. The method of claim 41, wherein said encapsulant is comprised of said light transmission control material.

45. The method of claim 38 further comprising providing phosphor remote to said light emitter.

46. The method of claim 45, wherein said phosphor is at least partially coated with said light transmission control material.

47. The method of claim 38, further comprising providing a cover over said at least one light emitter.

48. The method of claim 47, wherein said providing of said light transmission control material comprises applying said light transmission control material over said cover.

49. The method of claim 47, wherein said cover is comprised of said light transmission control material.

50. The method of claim 39, wherein said light transmission control material changes from masking to less masking in response to thermal changes.

51. The method of claim 50, further comprising thermally coupling said light transmission control material to said at least one light emitter.

52. The method of claim 51, wherein said thermal coupling comprises providing a conductive material in thermal contact with said light transmission control material and said at least one light emitter.

53. The method of claim 52, wherein said conductive material is transparent.

54. The method of claim 39, wherein said light transmission control material changes from masking to less masking in response to an electrical signal.

55. The method of claim 54, further comprising electrically coupling said light transmission control material to said at least one light emitter.

56. The method of claim 55, wherein said electrical coupling comprises providing a transparent electrode in contact with said light transmission control material and said at least one light emitter.

57. The method of claim 38, wherein said light transmission control material is applied to said encapsulation by molding.

58. The LED package of claim 47, wherein said cover disperses light in a desired pattern.

59. A light emitting device, comprising:

a light emitting diode (LED); and

a diffusing material at least at least partially covering said LED, wherein said diffusing material is less diffusing when said LED is active compared to when said LED is active.

60. The device of claim 59, wherein said diffusing material becomes less diffusing in response to thermal changes.

61. The device of claim 59, wherein said diffusing material becomes less diffusing in response to electricity.

62. The device of claim 59, wherein said diffusing material becomes less diffusing in response to light.

63. A light emitting device, comprising:

a light emitting diode (LED); and

a masking material optically coupled to said LED, said masking material changing from masking to light transmitting in response to light from said LED.