Light emitting diode package with optical element

• US 8,735,920 B2
• Filed: 07/31/2006
• Issued: 05/27/2014
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Ibbetson, James, Tarsa, Eric, Leung, Michael, Becerra, Maryanne, Keller, Bernd
• Primary Examiner(s): HUBER, ROBERT T
• Application Number:
  US11/496,922
• Publication Number:
  US 20080023711A1
• Time in Patent Office: 2,857 Days
• Field of Search: 257/88, 257/89, 257/98, 257/100, 257/E33.068, 257/E33.07, 257/E33.073, 438/26, 438/27, 438/29
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2933/005 relating to encapsulations
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A light emitting diode (LED) package comprising a substrate with an LED chip mounted to the substrate and in electrical contact with it. An inner material covers the LED chip, and a lens covers the inner material with the lens material being harder than the inner material. An adhesive is arranged between the substrate and the lens to hold the lens to the substrate and to compensate for different coefficients of thermal expansion (CTE) between the lens and the remainder of the package. A method for forming an LED package comprises providing a substrate with a first meniscus ring on a surface of the substrate. An LED chip is mounted to the substrate, within the meniscus ring. An inner material is deposited over the LED chip, and a lens material in liquid form is deposited over the inner material. The lens material held in a hemispheric shape by the first meniscus feature and the lens material is cured making it harder than the inner material.

Claims

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

a substrate;

at least one LED chip on said substrate;

an inner material covering said at least one LED chip;

a lens covering said inner material, said lens being harder than said inner material;

a first meniscus holding feature having a top surface and at least one outer side surface that faces away from said lens, said lens on said first meniscus holding feature and extending out to a falling edge defined by the intersection of said top surface and said at least one outer side surface of said meniscus holding feature, wherein a shape of said lens is at least partially defined by a meniscus formed by said first meniscus holding feature, wherein said meniscus holds the shape of said lens over said inner material; and

an adhesive between said first meniscus holding feature and said lens, said adhesive holding said lens to said substrate, said adhesive disposed such that said lens and the remainder of said package can readily expand and contract even though said lens and said package may have different coefficients of thermal expansion.

2. The LED package of claim 1, wherein said at least one LED chip is in electrical contact with said substrate.

3. The LED package of claim 1, further comprising a second meniscus holding feature having a top surface and an outer side surface, said inner material extending out to a falling edge defined by the intersection of said top and side surfaces of said second meniscus holding feature.

4. The LED package of claim 1, wherein said inner material comprises a silicone.

5. The LED package of claim 1, wherein said inner material has a lower Shore durometer reading than said lens.

6. The LED package of claim 1, wherein said lens comprises silicone.

7. The LED package of claim 1, wherein said inner material further comprises light conversion materials.

8. The LED package of claim 1, further comprising at least one wire bond to apply an electrical signal to said at least one LED, at least part of said at least one wire bond covered by said inner material.

9. The LED package of claim 1, wherein said inner material and said lens are hemispheric shaped.

10. The LED package of claim 1, wherein said meniscus is formed at said first meniscus holding feature.

11. The LED package of claim 1, wherein said adhesive has a higher durometer reading than said inner material and has a lower durometer reading than said lens.

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

a substrate;

at least one LED chip mounted to said substrate;

an inner material covering said at least one LED chip;

a first meniscus holding feature on said substrate, said first meniscus holding feature having a top surface and at least one outer side surface that faces away from a lens;

said lens made of a material that is harder than said inner material, said lens having a substrate contacting surface and mounted on said substrate and said first meniscus holding feature and over said inner material, said lens extending out to a falling edge defined by the intersection of said top surface and said at least one outer side surface of said first meniscus holding feature, said lens at least partially defined by a first meniscus, wherein said first meniscus holds a shape of said lens over said inner material;

an adhesive between said substrate and said lens, said adhesive holding said lens to said substrate, wherein said adhesive is between said first meniscus holding feature and said lens; and

a second meniscus holding feature having a top surface and an outer side surface that faces away from said inner material, said inner material having a top surface defined by a second meniscus extending on said top surface out to a falling edge defined by the intersection of said top surface and outer side surface of said second meniscus holding feature;

wherein an inner surface of said lens is at least partially defined by said second meniscus.

13. The LED package of claim 12, wherein said adhesive further compensates for different coefficients of thermal expansion between said lens and the remainder of said package.

14. The LED package of claim 12, wherein said inner material further comprises light conversion materials.

15. The LED package of claim 12, further comprising at least one wire bond to apply an electrical signal to said at least one LED chip, at least part of said at least one wire bond covered by said inner material.

16. The LED package of claim 12, wherein said inner material has a hardness measuring less than 50 on Shore durometer 00 Scale.

17. The LED package of claim 12, wherein said lens has a hardness measuring greater than 30 on Shore durometer A Scale.

18. The LED package of claim 12, wherein said meniscus is formed at said first meniscus holding feature.

19. The LED package of claim 12, wherein said adhesive has a higher durometer reading than said inner material and has a lower durometer reading than said lens.

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

a substrate;

at least one LED chip on said substrate;

an inner material covering said at least one LED chip;

a lens covering said inner material, said lens being harder than said inner material;

a first meniscus holding feature having a top surface and at least one outer side surface that faces away from said lens, said lens on said first meniscus holding feature and extending out to a falling edge defined by the intersection of said top surface and said at least one outer side surface of said meniscus holding feature, wherein a shape of said lens is at least partially defined by a meniscus formed by said first meniscus holding feature, wherein said meniscus holds the shape of said lens over said inner material; and

an adhesive between said substrate and said lens, said adhesive holding said lens to said substrate, said adhesive directly contacting said lens, said adhesive disposed such that said lens and the remainder of said package can readily expand and contract even though said lens and said package may have different coefficients of thermal expansion.

21. The LED package of claim 20, wherein said at least one LED chip is in electrical contact with said substrate.

22. The LED package of claim 20, further comprising a second meniscus holding feature having a top surface and an outer side surface, said inner material extending out to a falling edge defined by the intersection of said top and side surfaces of said second meniscus holding feature.

23. The LED package of claim 20, wherein said inner material comprises a silicone.

24. The LED package of claim 20, wherein said inner material has a lower Shore durometer reading than said lens.

25. The LED package of claim 20, wherein said lens comprises silicone.

26. The LED package of claim 20, wherein said inner material further comprises light conversion materials.

27. The LED package of claim 20, further comprising at least one wire bond to apply an electrical signal to said at least one LED, at least part of said at least one wire bond covered by said inner material.

28. The LED package of claim 20, wherein said inner material and said lens are hemispheric shaped.

29. The LED package of claim 20, wherein said meniscus is formed at said first meniscus holding feature.

30. The LED package of claim 20, wherein said adhesive has a higher durometer reading than said inner material and has a lower durometer reading than said lens.

31. The LED package of claim 20, wherein said adhesive is between said first meniscus holding feature and said lens.

32. The LED package of claim 20, wherein said meniscus is formed at said first meniscus holding feature.

33. The LED package of claim 20, wherein said adhesive has a higher durometer reading than said inner material and has a lower durometer reading than said lens.

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

a substrate;

at least one LED chip mounted to said substrate;

a first meniscus holding feature on said substrate, said first meniscus holding feature having a top surface and at least one outer side surface that faces away from a lens;

an inner material covering said at least one LED chip;

said lens made of a material that is harder than said inner material, said lens having a substrate contacting surface and mounted on said substrate and said first meniscus holding feature and over said inner material, said lens extending out to a falling edge defined by the intersection of said top surface and said at least one outer side surface of said first meniscus holding feature, said lens at least partially defined by a meniscus, wherein said meniscus holds a shape of said lens over said inner material;

a second meniscus holding feature having a top surface and an outer side surface that faces away from said inner material, said inner material extending on said top surface out to a falling edge defined by the intersection of said top surface and outer side surface of said second meniscus holding feature; and

adhesive between said substrate and said lens, said adhesive holding said lens to said substrate, said adhesive directly contacting the lens.

35. The LED package of claim 34, wherein said adhesive is between said first meniscus holding feature and said lens.

36. The LED package of claim 34, wherein said adhesive further compensates for different coefficients of thermal expansion between said lens and the remainder of said package.

37. The LED package of claim 34, wherein said inner material further comprises light conversion materials.

38. The LED package of claim 34, further comprising at least one wire bond to apply an electrical signal to said at least one LED chip, at least part of said at least one wire bond covered by said inner material.

39. The LED package of claim 34, wherein said inner material has a hardness measuring less than 50 on Shore durometer 00 Scale.

40. The LED package of claim 34, wherein said lens has a hardness measuring greater than 30 on Shore durometer A Scale.

41. The LED package of claim 34, wherein said meniscus is formed at said first meniscus holding feature.

42. The LED package of claim 34, wherein said adhesive has a higher durometer reading than said inner material and has a lower durometer reading than said lens.