Overmolded lens over LED die

• US 20060105485A1
• Filed: 02/28/2005
• Published: 05/18/2006
• Est. Priority Date: 11/15/2004
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.), Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Harbers, Gerard, West, Robert Scott, Martin, Paul S., Basin, Grigoriy, Hendriks, Robert F. M., Konijn, Frans H., Smits, Willem H.
• Granted Patent: US 7,344,902 B2
• Time in Patent Office: Days
• US Class Current: 438/27
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: G02B 19/0071 adapted to illuminate a complete hemisphere or a plane extending 360 degrees around the source
• CPC Class Codes: H01L 2224/0554 External layer
• CPC Class Codes: H01L 2224/0555 Shape
• CPC Class Codes: H01L 2224/0556 Disposition
• CPC Class Codes: H01L 2224/05568 the whole external layer protruding from the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/056 with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• 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 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/81 using a bump connector
• CPC Class Codes: H01L 2224/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 24/73 Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• 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 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/15787 : Ceramics, e.g. crystalline carbides, nitrides or oxides
• CPC Class Codes: H01L 2924/1815 : Shape
• CPC Class Codes: H01L 2924/19107 : off-chip wires
• CPC Class Codes: H01L 33/46 : Reflective coating, e.g. dielectric Bragg reflector
• 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 33/54 : having a particular shape
• CPC Class Codes: H01L 33/58 : Optical field-shaping elements
• CPC Class Codes: H05K 2201/10106 : Light emitting diode [LED]
• CPC Class Codes: H05K 3/284 : for encapsulating mounted components H05K1/185 takes precedence

Abstract

One or more LED dice are mounted on a support structure. The support structure may be a submount with the LED dice already electrically connected to leads on the submount. A mold has indentations in it corresponding to the positions of the LED dice on the support structure. The indentations are filled with a liquid optically transparent material, such as silicone, which when cured forms a lens material. The shape of the indentations will be the shape of the lens. The mold and the LED dice/support structure are brought together so that each LED die resides within the liquid silicone in an associated indentation. The mold is then heated to cure (harden) the silicone. The mold and the support structure are then separated, leaving a complete silicone lens over each LED die. This over molding process may be repeated with different molds to create concentric shells of lenses. Each concentric lens may have a different property, such as containing a phosphor, providing a special radiation pattern, having a different hardness value, or curable by a different technique (e.g., UV vs. heat).

Claims

1. A method for forming a lens over a light emitting diode (LED) die comprising:

providing an LED die attached to a support structure; and

molding a first lens of a first material over the die while attached to the support structure.

2. The method of claim 1 wherein molding the first lens further comprises curing the first material using a thermal or UV cure.

3. The method of claim 1 wherein molding the first lens comprises:

filling a first indentation in a first mold with a first lens material;

bringing the first mold and the support structure together so that the LED die is within the first lens material;

curing the liquid first lens material; and

removing the support structure from the first mold so that a first lens formed from the cured first lens material overlies the LED die.

4. The method of claim 1 wherein the support structure comprises a submount having metal leads in electrical contact with metal contacts on the LED die.

5. The method of claim 1 wherein the LED die is one of a plurality of LED dice affixed to the support structure.

6. The method of claim 1 wherein the first lens is formed in direct contact with the LED die.

7. The method of claim 1 wherein molding the first lens further comprises molding a pattern into a surface of the first lens for affecting an emitted light pattern.

9. The method of claim 1 further comprising providing an optical element affixed to the first lens to obtain a desired light pattern.

10. The method of claim 9 wherein the optical element comprises a second lens of a second material different from the first material.

11. The method of claim 9 wherein the optical element comprises a second lens of a second material different from the first material, and wherein providing the optical element comprises:

molding the second lens over the first lens; and

curing the second material.

12. The method of claim 9 wherein the optical element comprises a second lens of a second material different from the first material, and wherein providing the optical element comprises:

molding the second lens over the first lens, the second lens having a surface pattern comprising a Fresnel lens, a diffraction gradient, a binary pattern, pyramids, or cones.

13. The method of claim 9 wherein the optical element comprises a second lens of a second material harder than the first material.

14. The method of claim 10 wherein a range of hardness of the first lens is Shore 00 5-90, and the hardness of the second lens is greater than Shore A 30.

15. The method of claim 9 wherein providing the optical element comprises depositing a reflective material on an outer surface of the first lens.

16. The method of claim 9 wherein the optical element is a collimating lens.

17. The method of claim 9 wherein the optical element is a side-emitting lens.

18. The method of claim 9 wherein the optical element comprises a second lens of a second material different from the first material, wherein the first material and the second material comprise silicone, epoxy, or a silicone/epoxy hybrid.

19. The method of claim 9 wherein providing the optical element comprises:

providing a second mold having a second indentation filled with a second lens material;

bringing together the second mold and the support structure, having attached to it the LED die having the first lens, so that the first lens is within the second lens material in the second indentation;

curing the second lens material; and

removing the support structure from the second mold so that the second lens material forms a first shell over the first lens.

20. The method of claim 9 wherein providing the optical element comprises providing an optical element directly on the first lens.

21. The method of claim 9 wherein the optical element comprises a second lens over the first lens, the first lens containing a first phosphor, and the second lens containing a second phosphor.

22. The method of claim 21 wherein a combination of the LED light and the light emitted by the phosphors creates white light.

23. The method of claim 9 wherein the optical element comprises a second lens over the first lens, the method further comprising molding a third lens over the second lens, the first lens containing a first phosphor, the second lens containing a second phosphor, and the third lens containing a third phosphor.

8. The method of 7 wherein the pattern comprises a Fresnel lens, a diffraction grating, a binary pattern, pyramids, or cones.

24. A method for forming a lens over a light emitting diode (LED) die comprising:

providing an LED die attached to a support structure;

forming a mold on the support structure; and

molding a first lens of a first material over the die while attached to the support structure, using the mold on the support structure to define the shape of the first lens.

25. The method of claim 24 wherein molding the first lens comprises depositing a lens material in the mold on the support structure and then curing the lens material.

26. A light emitting device comprising:

a light emitting diode (LED) die attached to a support structure; and

a first lens molded over the LED die and encapsulating the LED die.

27. The device of claim 26 further comprising an optical element affixed to the first lens to obtain a desired light pattern.

28. The device of claim 27 wherein the optical element comprises a second lens of a second material different from the first material.

29. The device of claim 28 wherein the second lens is molded over the first lens.

30. The device of claim 28 wherein the second lens has a pattern molded into its surface for affecting an emitted light pattern.

31. The device of claim 30 wherein the pattern comprises a Fresnel lens, a diffraction grating, a binary pattern, pyramids, or cones.

32. The device of claim 26 wherein the first lens has a pattern molded into its surface for affecting an emitted light pattern.

33. The device of claim 32 wherein the pattern comprises a Fresnel lens, a diffraction grating, a binary pattern, pyramids, or cones.

34. The device of claim 26 wherein the LED die is one of a plurality of LED dice affixed to the support structure.

35. The device of claim 26 further comprising a backlight for a liquid crystal display, the backlight incorporating the LED and first lens.

36. The device of claim 26 further comprising a rear projection television, the television incorporating the LED and first lens.