Light emitting diode package element with internal meniscus for bubble free lens placement

• US 7,804,147 B2
• Filed: 07/31/2006
• Issued: 09/28/2010
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Yadev, Praveen, Yuan, Thomas C., Becerra, Maryanne, Tarsa, Eric
• Primary Examiner(s): Thai; Luan C
• Application Number:
  US11/496,918
• Publication Number:
  US 20080026498A1
• Time in Patent Office: 1,520 Days
• Field of Search: 257431-435, 257/51.018, 257/E51.02, 257/E33.073
• US Class Current: 257/433
• 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 33/52 Encapsulations
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A method for fabricating a light emitting diode (LED) package comprising providing an LED chip and covering at least part of the LED chip with a liquid encapsulant having a radius of curvature. An optical element is provided having a bottom surface with at least a portion having a radius of curvature larger than the liquid encapsulant. The larger radius of curvature portion of the optical element is brought into contact with the liquid encapsulant. The optical element is then moved closer to the LED chip, growing the contact area between said optical element and said liquid encapsulant. The liquid encapsulant is then cured. A light emitting diode comprising a substrate with an LED chip mounted to it. A meniscus ring is on the substrate around the LED chip with the meniscus ring having a meniscus holding feature. An inner encapsulant is provided over the LED chip with the inner encapsulant having a contacting surface on the substrate, with the meniscus holding feature which defines the edge of the contacting surface. An optical element is included having a bottom surface with at least a portion that is concave. The optical element is arranged on the substrate with the concave portion over the LED chip. A contacting encapsulant is included between the inner encapsulant and optical element.

Claims

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

a substrate with an LED chip mounted to it;

a meniscus forming feature on said substrate around said LED chip, said meniscus forming feature comprising an edge defined by the intersection of an upper surface of said meniscus forming feature opposite said substrate and a side surface of said meniscus forming feature facing away from said LED chip;

an inner encapsulant over said LED chip and having a contacting surface on said substrate, said meniscus forming feature defining the edge of said contacting surface;

an optical element having a bottom surface with at least a portion that is concave, said optical element on said substrate with said concave portion over said LED chip; and

a contacting encapsulant between said inner encapsulant and said optical element.

2. The LED package of claim 1, wherein said optical element comprises a substantially hemispheric lens.

3. The LED package of claim 1, wherein said LED chip is at least partially within said concave portion of said optical element.

4. The LED package of claim 1, wherein the inner encapsulant has a radius of curvature and said optical element concave portion has a radius of curvature, said concave portion having a larger radius of curvature than said inner encapsulant.

5. The LED package of claim 1, wherein there is substantially no air trapped between said optical element and said contacting encapsulant.

6. The LED package of claim 1, wherein said meniscus forming feature further comprises an optical element retention feature.

21. The LED package of claim 1, wherein said inner encapsulant extends over at least a portion of said upper surface of said meniscus forming feature.

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

an LED chip;

a meniscus forming feature disposed around said LED chip, said meniscus forming feature comprising an edge defined by the intersection of an upper surface of said meniscus forming feature and a side surface of said meniscus forming feature facing away from said LED chip;

an encapsulant over said LED chip; and

an optical element with a bottom surface, said bottom surface having at least a portion with a radius of curvature larger than a radius of curvature of said encapsulant prior to curing, said bottom surface arranged to conformally contact an exposed surface of said encapsulant such that substantially no air is trapped between the two.

8. The LED package of claim 7, wherein said bottom surface of said optical element comprises a concave portion, said LED chip at least partially within said concave portion.

9. The LED package of claim 7, wherein said optical element is a substantially hemispheric lens.

10. The LED package of claim 7, further comprising a substrate, said LED chip mounted to said substrate.

11. The LED package of claim 7, wherein said encapsulant is held in a substantially hemispheric shape by said meniscus forming feature prior to curing.

12. The LED package of claim 7, wherein said encapsulant comprises an inner encapsulant and a contacting encapsulant, said inner encapsulant held in a substantially hemispheric shape by said meniscus forming feature prior to curing and said contacting encapsulant being on said inner encapsulant.

13. The LED package of claim 7, wherein said meniscus forming feature further comprises an optical element retention feature.

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

a substrate with a plurality of LED chips;

an inner encapsulant over each of said LED chips, said inner encapsulant having a contacting surface on said substrate;

a meniscus forming feature on said substrate around each of said LED chips, said meniscus forming feature comprising an edge defined by the intersection of an upper surface of said meniscus forming feature opposite said substrate and a side surface of said meniscus forming feature facing away from said LED chip;

an optical element over each of said LED chips, each optical element having a bottom surface with at least a portion that is concave, with said concave portion over said LED chip; and

a contacting encapsulant between each said inner encapsulant and said optical element associated therewith.

15. The LED array package of claim 14, wherein said LED chips are mounted to said substrate so that electrical signals applied to said substrate are conducted from said substrate to said LED chips.

16. The LED array package of claim 14, wherein each said meniscus forming feature has a meniscus holding feature defined by an edge of each said inner encapsulant contacting surface.

17. The LED array package of claim 14, wherein each of said LED chips is at least partially within said concave portion of its said optical element.

18. The LED array package of claim 14, wherein the inner encapsulant has a radius of curvature and said optical element concave portion has a radius of curvature, said concave portion having a larger radius of curvature than said inner encapsulant.

19. The LED array package of claim 14, wherein substantially no air is trapped between each said optical element and its said contacting encapsulant.

20. The LED array package of claim 16, wherein said meniscus forming feature further comprises an optical element retention feature.