Coated phosphors and light emitting devices including the same

• US 8,729,790 B2
• Filed: 06/03/2011
• Issued: 05/20/2014
• Est. Priority Date: 06/03/2011
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Seibel, Harry A. II, Collins, Brian Thomas
• Primary Examiner(s): Hanley, Britt D
• Application Number:
  US13/152,833
• Publication Number:
  US 20120306354A1
• Time in Patent Office: 1,082 Days
• Field of Search: None
• US Class Current: 313/503
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/883 with zinc or cadmium
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• 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 2924/00014 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 33/005 Processes
• CPC Class Codes: H01L 33/26 Materials of the light emitting region
• CPC Class Codes: H01L 33/502 Wavelength conversion materials

Abstract

Provided according to embodiments of the invention are method of coating a phosphor that include contacting the phosphor with a sol comprising at least one of silica, alumina, borate and a precursor thereof, to form a coating on the phosphor; and heating the phosphor. Also provided are phosphors that are coated with alumina, silica and/or borate, and light emitting devices that include such phosphors.

Claims

1. A light emitting device, comprising:

a solid state lighting source;

a lens overlying the solid state lighting source; and

a phosphor that is coated with alumina, silica and/or borate and is optically coupled to the solid state lighting source, wherein the phosphor has a du′

v′

of less than 0.0015 after 840 hours at 85°

C. and 85% relative humidity.

2. The light emitting device of claim 1, wherein the phosphor is a reactive phosphor.

3. The light emitting device of claim 2, wherein the reactive phosphor comprises a nitride phosphor.

4. The light emitting device of claim 2, wherein the reactive phosphor comprises an oxynitride phosphor.

5. The light emitting device of claim 2, wherein the reactive phosphor comprises at least one of (Sr_1-xCa_x)(Ga_1-yAl_y)₂(S_1-zSe_z)₄, activated with Eu and/or Pr, and (Ca_1-xSr_x)(S_1-ySe_y), activated with Eu.

6. The light emitting device of claim 1, wherein the phosphor has an average particle size in a range of 2 to 25 microns.

7. The light emitting device of claim 1, further comprising a green and/or yellow phosphor.

8. The light emitting device of claim 1, wherein the lens comprises the phosphor.

9. The light emitting device of claim 1, wherein the phosphor is coated on the solid state lighting source.