LIGHT EMITTER DEVICES AND METHODS FOR LIGHT EMITTING DIODE (LED) CHIPS

• US 20140217433A1
• Filed: 01/30/2014
• Published: 08/07/2014
• Est. Priority Date: 11/22/2010
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Hussell, Christopher P., Abare, Amber C., Andrews, Peter Scott, Joo, Sung Chul, Tudorica, Florin A.
• Granted Patent: US 9,000,470 B2
• Time in Patent Office: Days
• US Class Current: 257/89
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48228 the bond pad being disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83447 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/83 using a layer connector
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/00014 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 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/10156 at the periphery
• CPC Class Codes: H01L 2924/12035 Zener diode
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2933/0041 : relating to wavelength conversion elements
• CPC Class Codes: H01L 2933/005 : relating to encapsulations
• CPC Class Codes: H01L 33/505 : characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/507 : the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/52 : Encapsulations
• CPC Class Codes: H01L 33/54 : having a particular shape
• CPC Class Codes: H01L 33/56 : Materials, e.g. epoxy or silicone resin

Abstract

Light emitter devices for light emitting diodes (LED chips) and related methods are disclosed. In one embodiment a light emitter device includes a substrate and a chip on board (COB) array of LED chips disposed over the substrate. A layer having wavelength conversion material provided therein is disposed over the array of LED chips for forming a light emitting surface from which light is emitted upon activation of the LED chips. In some aspects, the wavelength conversion material includes phosphoric or lumiphoric material that is settled and/or more densely concentrated within one or more predetermined portions of the layer. In some aspects, the devices and methods provided herein can comprise a lumen density of approximately 30 lm/mm² or greater.

Claims

1. A light emitter device comprising:

a substrate;

an emission area comprising an array of light emitting diode (LED) chips disposed over a planar surface of the substrate; and

a layer of material disposed over the array of LED chips, the layer comprising a non-uniform distribution of one or more wavelength conversion materials provided therein; and

the device having a lumen density of at least 30 lm/mm² or more.

2. The device of claim 1, wherein the device comprises a lumen density of at least 60 lm/mm² or more.

3. The device of claim 1, wherein the device comprises a lumen density of at least 90 lm/mm² or more.

4. The device of claim 1, wherein a packing density of the LED chips over a floor of the emission area is between approximately 25% and 50%.

5. The device of claim 1, wherein the emission area comprises a diameter of approximately 6 mm or more.

6. The device of claim 1, wherein the emission area comprises a diameter of approximately 9 mm or more.

7. The device of claim 1, wherein the emission area comprises a diameter of approximately 19 mm or more.

8. The device of claim 1, wherein the wavelength conversion material comprises phosphor for converting light emitted by at least one LED chip to a peak wavelength in a red color.

9. The device of claim 1, wherein the wavelength conversion material comprises phosphor for converting light emitted by at least one LED chip to a peak wavelength in a yellow color.

10. The device of claim 1, wherein the wavelength conversion material comprises phosphor for converting light emitted by at least one LED chip to a peak wavelength in a green color.

11. The device of claim 1, wherein a higher density of wavelength conversion material is provided proximate a bottom of the layer, and wherein a lower density of wavelength conversion material is provided proximate a top of the layer.

12. The device of claim 1, comprising two or more wavelength conversion materials provided in the layer.

13. The device of claim 1, wherein the layer comprises silicone encapsulant.

14. The device of claim 1, wherein a retention dam is provided about the emission area.

15. The device of claim 1, wherein the substrate comprises ceramic.

16. The device of claim 1, wherein the array of LED chips is arranged in multiple different patterns.

17. The device of claim 1, wherein each LED chip in the array of LED chips is configured to emit a same color of light.

18. The device of claim 1, wherein at least two LED chips in the array of LED chips are configured to emit different colors of light.

19. The device of claim 1, wherein each LED chip in the array of LED chips is spaced apart from a next closest LED chip by at least approximately 50 μ

m or more.

20. The device of claim 1, wherein each LED chip in the array of LED chips is spaced apart from a next closest LED chip by at least approximately 200 μ

m or more.

21. The device of claim 1, wherein each LED chip in the array of LED chips is spaced apart from a next closest LED chip by at least approximately 300 μ

m or more.

22. A light emitter device comprising:

a substrate;

an emission area comprising an array of light emitting diode (LED) chips disposed over the substrate; and

a layer of material disposed over the array of LED chips, the layer comprising a non-uniform distribution of wavelength conversion material provided therein; and

wherein the array of LED chips occupies approximately 25% or more of the light emission area.

23. The device of claim 22, wherein the device comprises a lumen density of at least 30 lm/mm² or more.

24. The device of claim 22, wherein the device comprises a lumen density of at least 60 lm/mm² or more.

25. The device of claim 22, wherein the device comprises a lumen density of at least 90 lm/mm² or more.

26. The device of claim 22, wherein the emission area comprises a diameter of approximately 6 mm or more.

27. The device of claim 22, wherein the emission area comprises a diameter of approximately 9 mm or more.

28. The device of claim 22, wherein the emission area comprises a diameter of approximately 19 mm or more.

29. The device of claim 22, wherein the wavelength conversion material comprises a phosphor for converting light emitted by at least one LED chip to a peak wavelength in a red color, a yellow color, a green color, a blue color, a white color, or combinations thereof.

30. The device of claim 22, wherein the amount of wavelength conversion material gradually increases towards a floor of the emission area.

31. The device of claim 22, wherein the layer comprises silicone encapsulant.

32. The device of claim 22, wherein a retention dam is provided about the emission area.

33. The device of claim 22, wherein the substrate comprises ceramic.

34. The device of claim 22, wherein chip spacing between two adjacent LED chips in the array of LED chips is approximately 50 μ

m or more.

35. The device of claim 22, wherein chip spacing between two adjacent LED chips in the array of LED chips is approximately 200 μ

m or more.

36. The device of claim 22, wherein chip spacing between two adjacent LED chips in the array of LED chips is approximately 300 μ

m or more.

37. A method of providing a light emitter device, the method comprising:

providing an array of light emitting diode (LED) chips over a substrate, wherein chip spacing between any two adjacent LED chips in the array of LED chips is at least approximately 50 μ

m or more;

providing a viscous material over the array of LED chips, wherein at least one wavelength conversion material is dispersed therein; and

causing the wavelength conversion material to settle within a predefined portion of the viscous material over the array of LED chips.

38. The method of claim 37, wherein chip spacing between any two adjacent LED chips in the array of LED chips is at least approximately 200 μ

m or more.

39. The method of claim 37, wherein the chip spacing between any two adjacent LED chips in the array of LED chips is at least approximately 300 μ

m or more.

40. The method of claim 37, wherein providing the viscous material over the array of LED chips comprises dispensing silicone encapsulant over the LED chips.

41. The method of claim 37, wherein the wavelength conversion material comprises a phosphor for converting light emitted by at least one LED chip of the array of LED chips to a peak wavelength in a red color, a yellow color, a green color, a blue color, a white color, or combinations thereof.

42. The method of claim 37, wherein the array of LED chips forms a light emission area, and wherein a packing density of the LED chips over a floor of the emission area is between approximately 25% and 50%.

43. The method of claim 37, wherein the array of LED chips forms a light emission area having a diameter of approximately 6 mm or more.

44. The method of claim 37, wherein the array of LED chips forms a light emission area having a diameter of approximately 9 mm or more.

45. The method of claim 37, wherein the array of LED chips forms a light emission area having a diameter of approximately 19 mm or more.

46. The method of claim 37, wherein the wavelength conversion material comprises at least two different types of phosphor.

47. The method of claim 37, wherein the wavelength conversion material comprises at least three different types of phosphor.

48. The method of claim 37, wherein causing the wavelength conversion material to settle within a predefined portion of the viscous material comprises changing a viscosity of the viscous material.

49. The method of claim 37, wherein causing the wavelength conversion material to settle within a predefined portion of the viscous material comprises heating the viscous material.

50. The method of claim 37, wherein causing the wavelength conversion material to settle within a predefined portion of the viscous material comprises centrifuging the viscous material.

51. The method of claim 37, wherein causing the wavelength conversion material to settle within a predefined portion of the viscous material comprises vibrating the viscous material.

52. The method of claim 37, wherein causing the wavelength conversion material to settle within a predefined portion of the viscous material comprises causing a first layer of predominantly red phosphor to settle adjacent a second layer of predominantly yellow phosphor.

53. A light emitter device comprising:

a planar substrate;

at least one light emitting diode (LED) chip disposed over the substrate; and

an encapsulant comprising a first encapsulant portion predominantly comprising at least a first wavelength conversion material and also comprising a second wavelength conversion material, and the encapsulant comprising a second encapsulant portion disposed over the first encapsulant portion and comprising the second wavelength conversion material.

54. The device of claim 53, further comprising a raised barrier disposed over the substrate at least partially around the LED chip.

55. The device of claim 53, wherein the first and second encapsulant portions each comprise silicone.

56. The device of claim 53, wherein the second encapsulant portion comprises the second wavelength conversion material as well as some of the first wavelength conversion material, wherein an amount of the second wavelength conversion material is more than an amount of the first wavelength conversion material.

57. The device of claim 53, wherein the first wavelength conversion material comprises yellow phosphor and the second wavelength conversion material comprise a non-yellow phosphor.

58. The device of claim 57, wherein the non-yellow phosphor comprises a red or green phosphor.

59. The device of claim 53, wherein a particle size of the first wavelength conversion material is larger than a particle size of the second wavelength conversion material.

60. The device of claim 59, wherein the first and second wavelength conversion materials comprise a same phosphor color.

61. The device of claim 59, wherein the first and second wavelength conversion materials comprise different phosphor colors.

62. The device of claim 53, wherein the at least one LED chip comprises an array of LED chips.

63. The device of claim 53, wherein the second encapsulant portion comprising the second wavelength conversion material is devoid of the first wavelength conversion material.