Apparatus and method for coating a light source to provide a modified output spectrum

• US 20040166234A1
• Filed: 02/26/2003
• Published: 08/26/2004
• Est. Priority Date: 02/26/2003
• 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: Leong, Chan Meng, Chua, Bee Yin Janet, Tan, Boon Chun
• Application Number:
  US10/375,321
• Publication Number:
  US 20040166234A1
• Time in Patent Office: Days
• US Class Current: 427/64
• 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 2224/8592 Applying permanent coating, e.g. protective coating
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

The present invention provides a method and apparatus for coating a light source to provide a modified output spectrum. Liquid adhesive is applied to the light source to form an adhesive layer. Luminescent material is fluidized and at least a portion of the adhesive layer immersed in the fluidized luminescent material to form a coated light source. The luminescent material can be a mixture of a phosphor compound and a fluidization enhancement substance, such as fumed silica.

Claims

1. A method for coating a light source, the method comprising:

applying liquid adhesive to the light source to form an adhesive layer;

fluidizing luminescent material; and

immersing at least a portion of the adhesive layer in the fluidized luminescent material.

2. The method of claim 1, wherein the liquid adhesive is a liquid adhesive selected from the group consisting of epoxy-anhydride, epoxy-amine, transparent polyesters, crosslinkable polyurethanes, and ultraviolet (UV) curable epoxy resins.

3. The method of claim 1, wherein the liquid adhesive includes a surfactant.

4. The method of claim 1, further comprising heating the liquid adhesive.

5. The method of claim 1, further comprising heating the light source.

6. The method of claim 1, wherein applying liquid adhesive to the light source is performed by a technique selected from the group consisting of spraying, rolling, dipping, and printing.

7. The method of claim 1, wherein applying the liquid adhesive to the light source comprises spraying the liquid adhesive onto the light source utilizing a spraying device.

8. The method of claim 7, wherein the spraying device is selected from the group consisting of a thermal inkjet printer, a piezoelectric inkjet printer, a time pressure dispensing system, an industrial spraying machine, an ink spray marking machine, and a continuous ink jet technology machine.

9. The method of claim 7, further comprising monitoring viscosity of the liquid adhesive.

10. The method of claim 1, wherein the light source is selected from the group consisting of visible light emitting diodes, visible laser diodes, ultraviolet light emitting diodes, and ultraviolet laser diodes.

11. The method of claim 1, wherein the luminescent material is disposed within the adhesive layer.

12. The method of claim 1, wherein the luminescent material is disposed upon the adhesive layer.

13. The method of claim 1, wherein the luminescent material comprises:

a phosphor compound; and

a fluidization enhancement substance.

14. The method of claim 13, wherein the fluidization enhancement substance is a thixotropic agent.

15. The method of claim 13, wherein the fluidization enhancement substance is fumed silica.

16. The method of claim 1, further comprising heating the adhesive layer.

17. The method of claim 1, further comprising drying the adhesive layer before immersing at least a portion of the adhesive layer in the fluidized luminescent material.

18. The method of claim 1, further comprising maintaining the adhesive layer in a wet state when immersing at least a portion of the adhesive layer in the fluidized luminescent material.

19. The method of claim 1, further comprising curing the adhesive layer.

20. The method of claim 19, wherein curing the adhesive layer is performed by a technique selected from the group consisting of conventional heat curing, ultraviolet curing, and microwave curing.

21. The method of claim 1, further comprising verifying light output of the light source.

22. A method for making a lighting device, the method comprising:

providing a light emitting device;

spraying liquid adhesive on the light emitting device to form an adhesive layer;

fluidizing a mixture of a phosphor compound and fumed silica; and

immersing at least a portion of the adhesive layer in the fluidized mixture of the phosphor compound and the fumed silica.

23. The method of claim 22, wherein the light emitting device is disposed in a reflector cup.

24. An apparatus for coating a light source, the apparatus comprising:

means for applying liquid adhesive to the light source to form an adhesive layer; and

means for fluidizing luminescent material, the luminescent material fluidizing means adapted to receive at least a portion of the adhesive layer.

25. The apparatus of claim 24, further comprising means for curing the adhesive layer.