Increased light output light emitting device using multiple phosphors

• US 20060226772A1
• Filed: 04/06/2005
• Published: 10/12/2006
• Est. Priority Date: 04/06/2005
• 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: Tan, Kheng Leng, Ou, Wen Ya, Oon, Su Lin, Ahmad, Azlida
• Application Number:
  US11/100,021
• Publication Number:
  US 20060226772A1
• Time in Patent Office: Days
• US Class Current: 313/512
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/625 with alkaline earth metals
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials

Abstract

A method for producing a light emitting device using two phosphors dispersed homogenously in a host matrix. The host matrix may be a polymer, such as heat and/or UV curable epoxy, silica glass, silica gel, silicone, etc. A dispersant, preferably inorganic, is applied to the host matrix to create a strong and stable three dimensional network within the host matrix. The BGS and ZnSeS phosphors are trapped equally in the three dimensional network, holding them homogenously in place within the host matrix. In one embodiment, the inorganic dispersant can be a hydrophobic formed silica, such as, for example, R812.

Claims

1. The method of making a light changing medium for a light emitting device, said method comprising:

creating a host medium in uncured form;

adding a dispersant into said host medium to create a three-dimensional structure within said host medium;

mixing into said three-dimensional structure particles of at least two radiant materials, and

curing said mixture.

2. The method of claim 1 wherein said radiant material comprises phosphor particles having different specific gravities.

3. The method of claim 2 wherein said phosphor particles comprise BGS and ZnSeS phosphors.

4. The method of claim 1 wherein said host medium is a polymer.

5. The method of claim 4 wherein said polymer is cured by at least one of the following:

heat, UV.

6. The method of claim 1 wherein said dispersant comprises a 10% mixture of R812.

7. The method of claim 1 further comprising:

positioning said cured host around a light emitting source such that light color from said source is modified by said two radiant materials within said cured host.

8. The method of claim 7 wherein said light emitting source is a LED.

9. The method of claim 1 wherein said dispersant is inorganic.

10. The method of claim 1 further comprising:

adding at least one of the following to said mixture;

adhesion promoter, UV inhibitor, oxidation stabilizer.

11. The method of claim 1 further comprising:

adding a UV inhibitor to said mixture.

13. The method of claim 10 wherein said stabilized mixture comprises:

a polymer having a three dimensional structure created therein and wherein said phosphors have been cured within said structure.

14. The method of claim 13 wherein said phosphors within said structure are mixed so as to become, and remain, homogeneous.

15. The method of claim 14 wherein said structure is created by introducing an inorganic dispersant into said polymer when said polymer is in an uncured state.

16. The method of claim 13 wherein said phosphors are BGS and ZnSeS particles having a mean particle size in the range of 25 μ

m.

12. A lamp comprising:

a light source within said lamp;

at least one contained area around said light source within said lamp, said contained area comprising a stabilized mixture of at least two phosphors in particle form, said phosphors having different specific gravities and operative for modifying the color of the light from said light source.

17. A light emitting device comprising:

a light source; and

means for surrounding at least a portion of said light source with a stabilized homogeneous mixture of BGS and ZnSeS phosphors, said phosphors having a mean particle size in the range of 25 μ

m.

18. The device of claim 17 wherein said surrounding means comprising:

material mixed with said phosphors therein prior to being cured.

19. The device of claim 18 further comprising:

means for controlling the color of light produced from said light emitting device by adjusting the proportion of the respective phosphors.

20. The device of claim 18 wherein said curable material is a polymer selected from the list of:

silica gel, silica glass, silicone, epoxy.

21. The device of claim 20 wherein said polymer is cured by at least one of:

heat, UV.