LED PACKAGE WITH MULTIPLE ELEMENT LIGHT SOURCE AND ENCAPSULANT HAVING CURVED AND/OR PLANAR SURFACES

• US 20150179903A1
• Filed: 12/18/2014
• Published: 06/25/2015
• Est. Priority Date: 06/11/2012
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Nevins, Jeremy, Reiherzer, Jesse, Clark, Joseph, PUN, ARTHUR
• Granted Patent: US 10,468,565 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49113 the connectors connecting different bonding areas on the semiconductor or solid-state body to a common bonding area outside the body, e.g. converging wires
• CPC Class Codes: H01L 2224/49175 Parallel arrangements
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 24/49 of a plurality of wire connectors
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

LED packages are disclosed that are compact and efficiently emit light, and can comprise encapsulants with planar surfaces that refract and/or reflect light within the package encapsulant. The LED package are also directed to features or arrangements that allow for improved or tailored emission characteristic for LED packages according to the present invention. Some of these features or arrangements include, but are not limited to, higher ratio of light source size to submount size, the used of particular materials (e.g. different silicones) for the LED package layers, improved arrangement of a reflective layer, improved composition and arrangement of the phosphor layer, tailoring the shape of the encapsulant, and/or improving the bonds between the layers. There are only some of the improvements disclosed herein, with some of these resulting in LED packages the emit light with a higher luminous intensity over conventional LED packages.

Claims

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

a submount with a plurality of LED chips mounted on the submount, wherein the ratio of the area covered by the LED chips to the area covered by said submount is greater than 0.18.

2. The LED package of claim 1, wherein said one or more LED chips comprise four LED chips.

3. The LED package of claim 1, further comprising an encapsulant with planar surfaces.

4. The LED package of claim 1, further comprising an encapsulant with planar and curved surfaces.

5. The LED package of claim 1, further comprising a phosphor layer over at least some of said plurality of LED chips.

6. The LED package of claim 1, further comprising a reflective layer around at least one of said plurality of LEDs.

7. A light emitting diode (LED) package, comprising:

a submount with one LED chip mounted on the submount, wherein the ratio of the area covered by the LED chip to the area covered by said submount is greater than 0.431.

8. The LED package of claim 7, further comprising an encapsulant with planar surfaces.

9. The LED package of claim 7, further comprising an encapsulant with planar and curved surfaces

10. The LED package of claim 7, further comprising a phosphor layer over at least some of said plurality of LED chips.

11. The LED package of claim 7, further comprising a reflective layer around at least one of said plurality of LEDs.

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

a submount with a plurality of LED chips mounted on said submount with a space between adjacent LED chips; and

a phosphor layer covering at least two of said LED chips and comprising a bridge spanning the space said two LED chips.

13. The LED package of claim 12, comprising an air gap between the bottom of said bridge and said submount.

14. The LED package of claim 12, further comprising a filler in said space between said LED chips and below said bridge.

15. The LED package of claim 14, wherein the top surface of said filler is aligned with the top surface of said adjacent LED chips.

16. The LED package of claim 14, wherein the top surface of said filler is higher than the top surface of said adjacent LED chips.

17. The LED package of claim 12, wherein said bridge is in the direct emission path of light from said adjacent LED chips.

18. The LED package of claim 12, wherein said phosphor layer is dispensed on said adjacent LEDs and over said space, said phosphor layer having a viscosity in the range of 1-75 Pa·

S when dispensed.

19. The LED package of claim 12, wherein said phosphor layer comprises a phosphor in a binder, wherein the phosphor to binder ratio is 3 to 1 or greater.

20. The LED package of claim 12, wherein said phosphor layer comprises a phosphor in a binder, wherein the phosphor to binder ratio is 4 to 1 or greater.

21. The LED package of claim 12, wherein said phosphor layer has a thickness in the range of 40 to 50 μ

m.

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

a submount with a one or more LED chips on said submount; and

a phosphor layer covering at least one of said LED chips and the surface of said submount adjacent said one of said LED chips, said phosphor layer comprising a fillet portion at the corner of said submount and said at least one of said LED chips, said fillet portion covering the edge of said LED chip and having a curved surface.

23. The LED package of claim 23, wherein said phosphor layer is continuous from said submount to the top surface of said LED chip.

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

a submount with a one or more LED chips on said submount; and

a phosphor layer covering at least one of said LED chips and the surface of said submount adjacent said one of said LED chips;

a smoothing layer on said phosphor layer; and

a reflective layer on said smoothing layer and around said LED chip.

26. The LED package of claim 24, comprising a chemical bond between two or more of said layers.

27. The LED package of claim 24, comprising a chemical bond between said reflective layer and said encapsulant.

28. The LED package of claim 24, wherein said reflective layer is on said one or more LED chips.

29. The LED package of claim 24, wherein said smoothing layer is between said phosphor layer and said reflective layer.

32. The LED package of claim 24, wherein said reflective layer comprises a silicone, and said phosphor layer and said smoothing layer comprises a silicone, wherein there is a functional group mismatch between the reflective layer silicone and the silicone in said phosphor layer and/or said smoothing layer.

25. The LED package of claim 25, wherein said smoothing layer comprises silicone.

30. The LED package of 25, further comprising an encapsulant with planar and curved surfaces.

31. The LED package of claim 30, wherein said encapsulant comprises silicone and said phosphor layer and/or smoothing layer comprises a different silicone.

33. A light emitting diode (LED) package, comprising:

a light source mounted on a submount, wherein said LED packages with source sizes greater that 49 mm² emit light with an intensity greater than 35 lm/mm², source sizes between 25 and 49 mm² emit light with an intensity greater than 50 lm/mm², and source sizes less than 25 mm²;

emit light with an intensity greater than 70 lm/mm².

34. The LED package of claim 33, having source sizes greater than 49 mm² emitting light with an intensity greater than 50 lm/mm².

35. The LED package of claim 33, having a source size between 25 and 49 mm² and emitting light with an intensity greater than 70 lm/mm².

36. The LED package of claim 33, having a source size less than 25 mm² and emitting light with an intensity greater than 100 lm/mm².

37. The LED package of claim 33, wherein said light source comprises one or more LEDs.

38. The LED package of claim 37, wherein said light source comprises four LEDs.

39. The LED package of claim 33, further comprising a phosphor layer and encapsulant both comprising a methyl silicone.

40. The LED package of claim 33, further comprising a reflective layer and a phosphor layer and/or a smoothing layer, wherein there is a functional group mismatch between the reflective layer silicone and the silicone in said phosphor layer and/or said smoothing layer.

41. The LED package of claim 33, further comprising a phosphor layer, wherein said phosphor layer comprises a phosphor in a binder, wherein the phosphor to binder ratio is 3 to 1 or greater.

42. The LED package of claim 41, wherein the phosphor to binder ratio is 4 to 1 or greater.

43. The LED package of claim 41, wherein said phosphor layer has a thickness in the range of 40 to 50 μ

m.

44. The LED package of claim 33, further comprising an encapsulant with planar surfaces.

45. The LED package of claim 33, further comprising an encapsulant with planar and curved surfaces.

46. The LED package of claim 33, wherein said source comprises a plurality of LED chips and wherein the ratio of the area covered by said LED chips to the area covered by said submount is greater than 0.18.

47. The LED package of claim 33, wherein said light source one LED chip and wherein the ratio of the area covered by said LED chip to the area covered by said submount is greater than 0.431.