Molded lens over LED die

• US 20060105484A1
• Filed: 11/15/2004
• 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: West, Robert Scott, Martin, Paul S., Basin, Grigoriy
• Granted Patent: US 7,452,737 B2
• Time in Patent Office: Days
• US Class Current: 438/27
• CPC Class Codes: B29C 33/0022 Multi-cavity moulds B29C33/301 takes precedence
• CPC Class Codes: B29C 39/006 Monomers or prepolymers by reaction injection moulding B29C67/246
• CPC Class Codes: B29C 39/025 for making multilayered articles
• CPC Class Codes: B29C 43/021 characterised by the shape of the surface
• CPC Class Codes: B29C 43/18 incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles B29C43/206 takes precedence
• CPC Class Codes: B29L 2011/0016 Lenses
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• 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 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/01013 Aluminum [Al]
• CPC Class Codes: H01L 2924/01049 Indium [In]
• CPC Class Codes: H01L 2924/12041 LED
• 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 33/52 Encapsulations

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.

Claims

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

providing an LED die attached to a support structure;

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

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

curing the liquid first lens material until it hardens; and

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

2. The method of claim 1 wherein bringing the first mold and support structure together comprises bringing the first mold and support structure together so that the LED die is fully within the liquid first lens material, and wherein removing the support structure from the first mold comprises removing the support structure from the first mold so that the first lens formed from the hardened first lens material encapsulates the LED die.

3. The method of claim 1 wherein the liquid first lens material comprises silicone.

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 a flip-chip with metal contacts directly bonded to the metal leads of the submount.

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

7. The method of claim 1 wherein the LED die has a phosphor material coating at least one surface of the LED die.

8. The method of claim 1 further comprising:

providing a second mold having a second indentation filled with a liquid 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 liquid second lens material in the second indentation;

curing the liquid second lens material until it hardens; and

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

9. The method of claim 8 wherein the second lens material comprises a first phosphor material.

10. The method of claim 8 wherein the second lens material is different from the first lens material.

11. The method of claim 8 wherein the second lens material comprises a first phosphor material, wherein a light emission from the combination of the LED die and first phosphor material is a white light.

12. The method of claim 8 wherein the second lens material comprises a first phosphor material, the method further comprising:

providing a third mold having a third indentation filled with a liquid third lens material;

bringing together the third mold and support structure, having attached to it the LED die having the first shell over the first lens;

curing the liquid third lens material until it hardens; and

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

13. The method of claim 12 further comprising:

providing a fourth mold having a fourth indentation filled with a liquid fourth lens material, the fourth lens material comprising a second phosphor;

bringing together the fourth mold and support structure, having attached to it the LED die having the second shell over the first shell;

curing the liquid fourth lens material until it hardens; and

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

14. The method of claim 13 further comprising forming a fourth shell containing a third phosphor material overlying the third shell so that a light emission from the combination of the LED die, the first phosphor material, the second phosphor material, and the third phosphor material is a white light

15. The method of claim 1 wherein the LED die is a flip-chip.

16. The method of claim 1 wherein the LED die has at least one wire bond electrically connecting the LED die to the support structure.

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

18. A light emitting device comprising:

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

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

19. The device of claim 18 wherein the first lens is formed over the LED die by the process comprising:

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

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

curing the liquid first lens material until it hardens; and

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

20. The device of claim 18 further comprising at least one shell over the first lens formed by molding the at least one shell over the LED die.

21. The device of claim 18 wherein the first lens material comprises silicone.

22. The device of claim 18 wherein the support substrate is a submount having metal leads electrically connected to metal contacts on the LED die.

23. The device of claim 22 wherein the LED die is a flip-chip.

24. The device of claim 18 further comprising a backlight for a display, the backlight incorporating the light emitting diode and first lens.

25. The device of claim 24 wherein the display is a television.

26. The device of claim 18 further comprising a camera having as a flash the light emitting diode and first lens.