Light emitting diode utilizing a discrete wavelength-converting layer for color conversion

• US 20050006659A1
• Filed: 07/09/2003
• Published: 01/13/2005
• Est. Priority Date: 07/09/2003
• Status: Abandoned Application

• Current Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Ng, Kee Yean, Ou, Wen Ua
• Application Number:
  US10/616,759
• Publication Number:
  US 20050006659A1
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/32257 the layer connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil

Abstract

A method for fabrication of a light source and the light source fabricated by that method are disclosed. The light source is fabricated by mounting a chip having a primary light source on a substrate, the primary light source emitting light of a first wavelength. The chip is connected to power terminals on the substrate for powering the primary light source. A preformed transparent cap of constant thickness is mounted over the chip. The cap includes a wavelength converting material for converting a portion of the light of the first wavelength to a second wavelength. The primary light source is preferably an LED or laser diode. In one embodiment, the cap includes a phosphor that is suspended in a clear compound. In another embodiment, the cap includes a planar sheet of a single crystal phosphor.

Claims

1. A method for fabricating a light source comprising:

mounting a chip having a primary light source on a substrate, said primary light source emitting light of a first wavelength;

connecting power terminals on said chip to corresponding power terminals on said substrate for powering said primary light source; and

mounting a preformed transparent cap over said chip, said cap comprising a wavelength-converting material for converting a portion of said light of said first wavelength to a second wavelength.

2. The method of claim 1 wherein said primary light source comprises an LED.

3. The method of claim 1 wherein said primary light source comprises a laser diode.

4. The method of claim 1 wherein said transparent cap comprises a phosphor material suspended in a clear compound.

5. The method of claim 1 wherein said transparent cap comprises a planar sheet of a single crystal phosphor.

6. The method of claim 1 wherein said transparent cap comprises an inverted cavity, said chip being on a concave side of said cavity.

7. The method of claim 1 wherein said transparent cap comprises a spherical surface of constant thickness.

8. The method of claim 1 wherein said transparent cap comprises a planar sheet having a constant thickness.

9. A light source comprising:

a chip having a primary light source mounted on a substrate, said primary light source emitting light of a first wavelength, said chip having chip power terminals connected to corresponding terminals on said substrate for powering said primary light source; and

a transparent cap over said chip, said cap comprising a wavelength-converting material for converting a portion of said light of said first wavelength to a second wavelength and for transmitting the portion of said light that is not converted, said transparent cap comprising a layer of wavelength-converting material of a constant thickness.

10. The light source of claim 9 wherein said transmitted portion of said light is transmitted without scattering more than 50 percent of said transmitted light.

11. The light source of claim 9 wherein said primary light source comprises an LED.

12. The light source of claim 9 wherein said primary light source comprises a laser diode.

13. The light source of claim 9 wherein said transparent cap comprises a phosphor suspended in a transparent material.

14. The light source of claim 9 wherein said transparent cap comprises a planar sheet of a single crystal phosphor.

15. The light source of claim 9 wherein said transparent cap comprises an inverted cavity, said chip being on a concave side of said cavity.

16. The light source of claim 9 wherein said transparent cap comprises a spherical surface of constant thickness.