Method of uniform phosphor chip coating and led package fabricated using method

• US 20080079017A1
• Filed: 07/27/2007
• Published: 04/03/2008
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Laughner, Micheal, Andrews, Peter, Fu, Yankun, Letoquin, Ronan, Medendorp, Nicholas, Loh, Ban
• Granted Patent: US 7,943,952 B2
• Time in Patent Office: Days
• 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 2924/19107 off-chip wires
• 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 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

Methods for fabricating LED packages comprising providing an LED chip and covering at least part of it with a liquid medium. An optical element is provided and placed on the liquid medium. The optical element is allowed to settle to a desired level and the liquid medium is cured. LED packages are also disclosed that are fabricated using the disclosed methods.

Claims

1. A method for fabricating an LED package, comprising:

providing an LED chip;

covering at least part of said LED chip with a liquid medium;

providing an optical element;

placing said optical element on said liquid medium;

allowing said optical element to settle at a desired level;

curing said liquid encapsulant.

2. The method of claim 1, wherein said liquid medium comprises a material from the group thermoset plastics, silicones, and epoxies.

3. The method of claim 1, wherein said optical element comprises a lens.

4. The method of claim 1, wherein said optical element is optically coupled to said liquid medium.

5. The method of claim 1, further comprising providing a substrate and mounting said LED chip to said substrate.

6. The method of claim 1, wherein said liquid medium further comprises phosphors or diffusants.

7. The method of claim 1, further comprising a meniscus holding feature around said LED chip to hold said liquid medium in a desired shape prior to curing.

8. The method of claim 1, wherein said optical element further comprises a layer of conversion material.

9. The method of claim 1, wherein said optical element further comprises an optical design.

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

a substrate;

an LED chip mounted to said substrate;

cured medium over said LED chip;

an optical element having a bottom surface in contact with and optically coupled to said cured medium, said optical element over said LED chip, wherein said cured medium and said optical element have different coefficients of thermal expansion, said cured medium not laterally or horizontally constrained to allow expansion of said cured medium through thermal cycles.

11. The LED package of claim 10, wherein said cured medium comprises a material from the group thermoset plastics, silicones, and epoxies.

12. The LED package of claim 10, wherein said optical element comprises a lens.

13. The LED package of claim 10, wherein said cured medium further comprises phosphors or diffusants.

14. The LED package of claim 10, further comprising a meniscus holding feature on said substrate and around said LED chip.

15. The LED package of claim 10, wherein said optical element further comprises a layer of conversion material.

16. The LED package of claim 10, wherein said optical element further comprises an optical design.

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

a substrate;

an LED chip mounted to said substrate;

cured encapsulant over said LED chip, said cured encapsulant having a liquid form prior to curing;

an optical element having a bottom surface in contact with and optically coupled to said cured encapsulant, said optical element arranged over said LED chip at a desired level by depositing said cured encapsulant in liquid form over said LED chip, placing said optical element on said liquid encapsulant, allowing said optical element to settle, and curing said liquid encapsulant.

18. The LED package of claim 17, wherein said cured medium comprises a material from the group thermoset plastics, silicones, and epoxies.

19. The LED package of claim 17, wherein said optical element comprises a lens.

20. The LED package of claim 17, wherein said cured medium further comprises phosphors or diffusants.

21. The LED package of claim 17, further comprising a meniscus holding feature on said substrate and around said LED chip.

22. The LED package of claim 17, wherein said LED chip is in electrical contact with said substrate