Overmolded lens over LED die

• US 7,344,902 B2
• Filed: 02/28/2005
• Issued: 03/18/2008
• 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: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.)
• Inventors: Hendriks, Robert F. M., Konijn, Frans H., Harbers, Gerard, West, Robert Scott, Martin, Paul S., Basin, Grigoriy, Smits, Willem H.
• Primary Examiner(s): Chaudhari; Chandra
• Assistant Examiner(s): Reames; Matthew L.
• Application Number:
  US11/069,418
• Publication Number:
  US 20060105485A1
• Time in Patent Office: 1,114 Days
• Field of Search: 438/27, 438/26
• 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 lenses over a plurality of light emitting diode (LED) dies comprising:

providing a plurality of LED dies attached to a single substantially flat top surface of a support structure, the LED dies forming a two-dimensional pattern on the support structure;

molding a rounded first lens of a first material over each of the LED dies on the support structure while attached to the support structure, wherein the first lens is formed in direct contact with the LED dies, a shape of the first lens, determined by a shape of the mold, shaping a light emission;

molding a second lens of a second material different from the first material over each first lens after the first lens is formed to further shape the light emission; and

curing the second material.

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 dies are 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 dies.

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 dies.

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

6. The method of claim 1 wherein molding the second lens comprises molding the second lens to have a surface pattern comprising a Fresnel lens, a diffraction gradient, a binary pattern, pyramids, or cones.

7. The method of claim 1 wherein the second material is harder than the first material.

9. The method of claim 1 wherein the second lens is a collimating lens.

10. The method of claim 1 wherein the second lens is a side-emitting lens.

11. The method of claim 1 wherein the first material and the second material comprise silicone, epoxy, or a silicone/epoxy hybrid.

14. The method of claim 1 wherein the first lens contains a first phosphor, and the second lens contains a second phosphor.

15. The method of claim 14 wherein a combination of the LED light and the light emitted by the phosphors creates white light.

16. The method of claim 1, 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.

17. The method of claim 1 wherein the second lens has a pattern molded into its surface for affecting an emitted light pattern.

18. The method of claim 17 wherein the pattern comprises a Fresnel lens, a diffraction grating, a binary pattern, pyramids, or cones.

19. The method of claim 1 wherein the first lens contains a phosphor.

20. The method of claim 1 wherein the second lens contains a phosphor.

8. A method for forming lenses over a plurality of light emitting diode (LED) dies comprising:

providing a plurality of LED dies attached to a single substantially flat top surface of a support structure, the LED dies forming a two-dimensional pattern on the support structure;

molding a rounded first lens of a first material over each of the LED dies on the support structure while attached to the support structure, a shape of the first lens, determined by a shape of the mold, shaping a light emission; and

providing a second lens of a second material different from the first material over each first lens to further shape the light emission,

wherein the second material is harder than the first material, and 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.

12. A method for forming lenses over a plurality of light emitting diode (LED) dies comprising:

providing a plurality of LED dies attached to a single substantially flat top surface of a support structure, the LED dies forming a two-dimensional pattern on the support structure;

molding a rounded first lens of a first material over each of the LED dies on the support structure while attached to the support structure, a shape of the first lens, determined by a shape of the mold, shaping a light emission; and

providing a second lens of a second material different from the first material over each first lens to further shape the light emission,

wherein providing the second lens comprises;

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

bringing together the mold and the support structure, having attached to it the LED dies 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.

13. A method for forming lenses over a plurality of light emitting diode (LED) dies comprising:

providing a plurality of LED dies attached to a single substantially flat top surface of a support structure, the LED dies forming a two-dimensional pattern on the support structure;

molding a rounded first lens of a first material over each of the LED dies on the support structure while attached to the support structure, a shape of the first lens, determined by a shape of the mold, shaping a light emission; and

providing a second lens of a second material different from the first material over each first lens to further shape the light emission,

wherein providing the second lens comprises molding the second lens directly on the first lens.