LIGHT EMITTING DEVICE WITH PHOSPHOR WAVELENGTH CONVERSION

• US 20100164346A1
• Filed: 12/16/2009
• Published: 07/01/2010
• Est. Priority Date: 12/31/2008
• Status: Active Grant

• Current Assignee: Intematix Corporation
• Original Assignee: Intematix Corporation
• Inventors: Li, Yi-Qun, Yang, Haitao
• Granted Patent: US 8,390,193 B2
• Time in Patent Office: Days
• US Class Current: 313/46
• CPC Class Codes: F21S 10/02 changing colors F21S10/002 - F21S10/007, F21S10/04 take precedence
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21V 7/06 with parabolic curvature
• CPC Class Codes: F21V 7/30 the coatings comprising photoluminescent substances
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• 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 33/504 Elements with two or more wavelength conversion materials
• 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

Abstract

A light emitting device comprises: a thermally conductive substrate (MCPCB); at least one LED mounted in thermal communication with a surface of the substrate; a housing attached to the substrate and configured such the housing and substrate together define a volume that totally encloses the at least one LED, the housing comprising at least a part that is light transmissive (window); and at least one phosphor material provided on an inner surface of the housing within said volume said phosphor being operable to absorb at least a part of the excitation light emitted by the at least one light emitting diode and to emit light of a second wavelength range. The housing is attached to the substrate such that the volume is substantially water tight, preferably air/gas tight.

Claims

1. A light emitting device comprising:

a thermally conductive substrate;

at least one light emitting diode mounted in thermal communication with a surface of the substrate and operable to emit excitation light having a dominant wavelength in a first wavelength range;

a housing attached to the substrate and configured such that the housing and substrate together define a volume that totally encloses the at least one light emitting diode, the housing comprising at least a part that is light transmissive; and

at least one phosphor material provided on an inner surface of the housing within said volume, said phosphor being operable to absorb at least a part of the excitation light and to emit light having a dominant wavelength in a second wavelength range; and

wherein the housing is attached to the substrate such that the volume is at least water tight.

2. The device of claim 1, wherein an emission product of the device comprises light of the first and second wavelength ranges and appears white in color.

3. The device of claim 1, and comprising a plurality of light emitting diodes mounted in thermal communication with a surface of the substrate and wherein the housing is configured such that the housing and substrate together define a volume that totally encloses the plurality of light emitting diodes.

4. The device of claim 1, wherein the device has an emission product of intensity selected from the group consisting of:

at least 50 lumens;

at least 100 lumens;

at least 250 lumens; and

at least 500 lumens.

5. The device of claim 1, and further comprising at least partially filling the volume with a light transmissive thermally conductive material.

6. The device of claim 5, wherein the light transmissive thermally conductive material is selected from the group consisting of:

a gel;

a mineral oil; and

a thermally conductive polymer.

7. The device of claim 1, wherein the housing is attached to the substrate such that the volume is substantially gas tight.

8. The device of claim 7, and further comprising filling the volume with a gas selected from the group consisting of:

nitrogen;

neon;

argon;

krypton; and

xenon.

9. The device of claim 1, wherein the housing is attached to the substrate by a method selected from the group consisting of:

soldering;

brazing;

adhesive; and

a metal loaded epoxy.

10. The device according to claim 1, wherein the part of the housing that is light transmissive comprises an opening covered by a window attached to the housing.

11. The device according to claim 10, wherein the window is attached to the housing by a method selected from the group consisting of:

soldering;

an adhesive; and

a compression seal.

12. The device of claim 11, wherein the window is selected from the group consisting of:

a glass;

a silica glass;

a quartz glass, transparent alumina, a polymer material;

a polycarbonate; and

an acrylic.

13. The device of claim 12, wherein the housing comprises a thermally conductive material selected from the group consisting of:

a metal;

an invar alloy, aluminum;

copper;

a thermally conductive polymer; and

a thermally conductive ceramic.

14. The device of claim 1, wherein the housing comprises a substantially parabolic reflector.

15. The device of claim 1, wherein the housing comprises a material that is light transmissive.

16. The device of claim 15, wherein the housing is selected from the group consisting of:

a glass;

silica glass;

quartz glass;

transparent alumina;

a polymer material;

a polycarbonate; and

an acrylic.

17. The device of claim 15, wherein the housing comprises a hemispherical shell.

18. The device of claim 1, wherein the substrate is selected from the group consisting of a printed circuit board;

a metal core printed circuit board;

a ceramic circuit board, a thermally conducting ceramic;

a low temperature co-fired ceramic; and

alumina.

19. The device of claim 1, wherein a minimum distance from the light emitting surface of the at least one light emitting diode to the at least one phosphor material is in a range 0.2 mm to 1 mm.

20. The device of claim 1, wherein the phosphor material is a silicate-based material.

21. A white light emitting device comprising:

a) a thermally conductive substrate;

b) a plurality of light emitting diode mounted in thermal communication with a surface of the substrate and operable to emit excitation light having a dominant wavelength in a first wavelength range;

c) a housing attached to the substrate and configured such that the housing and substrate together define a volume that totally encloses the plurality of light emitting diodes, the housing comprising at least a part that is light transmissive; and

d) at least one phosphor material provided on an inner surface of the housing within said volume, said phosphor being operable to absorb at least a part of the excitation light and to emit light having a dominant wavelength in a second wavelength range, wherein the emission product of the device comprises light of the first and second wavelength ranges and appears white in color; and

wherein the housing is attached to the substrate such that the volume is at least water tight and wherein the emission product intensity of the device is at least 50 lumens.

22. The device according to claim 21, wherein the device has an emission product of intensity selected from the group consisting of:

at least 100 lumens;

at least 250 lumens; and

at least 500 lumens.

23. A light emitting device comprising:

a) a thermally conductive substrate;

b) at least one light emitting diode incorporating a phosphor material mounted in thermal communication with a surface of the substrate; and

c) a housing attached to the substrate and configured such that the housing and substrate together define a volume that totally encloses the at least one light emitting diode, the housing comprising at least a part that is light transmissive; and

wherein the housing is attached to the substrate such that the volume is at least water tight.