Solid-state light emitting devices with photoluminescence wavelength conversion

• US 8,957,585 B2
• Filed: 12/26/2013
• Issued: 02/17/2015
• Est. Priority Date: 10/05/2010
• Status: Active Grant

• Current Assignee: Feit Electric Company Incorporated
• Original Assignee: Intermatic Incorporated (Wpa Participações e Serviços SA)
• Inventors: Li, Yi-Qun, Melman, Jonathan, Yuan, Xianglong, Dai, Bing, Wang, Gang, Edwards, Charles
• Primary Examiner(s): Bowman, Mary Ellen
• Application Number:
  US14/141,275
• Publication Number:
  US 20140103373A1
• Time in Patent Office: 418 Days
• Field of Search: 257/88, 257/98, 313/46, 313/110, 313/512
• US Class Current: 313/512
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 23/005 the substrate is supporting also the light source
• CPC Class Codes: F21V 7/26 the material comprising photoluminescent substances
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• 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 2924/00012 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 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/502 Wavelength conversion materials

Abstract

A solid-state light emitting device comprises a light transmissive thermally conductive circuit board; an array of solid-state light emitters (LEDs) mounted on, and electrically connected to, at least one face of the circuit board; and a photoluminescence wavelength conversion component. The wavelength conversion component comprises a mixture of particles of at least one photoluminescence material (phosphor) and particles of a light reflective material. The emission product of the device comprises the combined light generated by the LEDs and the photoluminescence material. The wavelength conversion component can comprise a layer of the phosphor material and particles of a light reflective material applied directly to the array of LEDs in the form of an encapsulant. Alternatively the photoluminescence component is a separate component and remote to the array of LEDs such as tubular component that surrounds the LEDs.

Claims

1. A light emitting device comprising:

a light transmissive circuit board;

a first array of solid-state light emitters mounted on, and electrically connected to, a first face of the light transmissive circuit board, wherein the first array of solid-state light emitters are operable to generate excitation light; and

a photoluminescence wavelength conversion component comprising a mixture of particles of at least one photoluminescence material and particles of a light reflective material, wherein the photoluminescence wavelength conversion component is configured such that in operation a portion of the excitation light generated by the first array solid-state light emitter is emitted through the photoluminescence wavelength conversion component to contribute to a final visible emission product.

2. The light emitting device of claim 1, further comprising a second array of solid-state light emitters mounted on, and electrically connected to, a second face of the light transmissive circuit board.

3. The light emitting device of claim 1, wherein the light transmissive circuit board has a transmittance of at least 50% to visible light.

4. The light emitting device of claim 1, wherein the light transmissive circuit board is thermally conductive.

5. The light emitting device of claim 4, wherein at least a part of the light transmissive circuit board is selected from the group consisting of:

magnesium oxide, sapphire, aluminum oxide, quartz glass, aluminum nitride and diamond.

6. The light emitting device of claim 1, wherein the photoluminescence component comprises a mixture of the at least one photoluminescence material and particles of the light reflective material applied directly to the, or each, array of solid-state light emitters.

7. The light emitting device of claim 1, wherein the photoluminescence component is remote to the, or each, array of solid-state light emitters.

8. The light emitting device of claim 7, wherein a surface of the wavelength conversion component is locatable at a distance of at least 5 mm from the plurality of solid-state light emitters.

9. The light emitting device of claim 7, wherein the wavelength conversion component comprises a substantially cylindrical tube.

10. The light emitting device of claim 1, wherein the light reflective material has a particle size in a range selected from the group consisting of:

0.01 μ

m to 10 μ

m;

0.01 μ

m to 1 μ

m and 0.1 μ

m to 1 μ

m.

11. The light emitting device of claim 1, wherein a weight percent loading of light reflective material to the at least one photoluminescence material is in a range selected from the group consisting of:

0.01% to 10%;

0.01% to 1%;

0.1% to 1% and 0.5% to 1%.

12. The light emitting device of claim 1, wherein the light reflective material is selected from the group consisting of:

magnesium oxide, titanium dioxide, barium sulfate and combinations thereof.

13. The light emitting device of claim 1, wherein the wavelength conversion component is selected from the group consisting of:

a light transmissive substrate on which the mixture of photoluminescence material and light reflective material is provided as at least one layer and a light transmissive substrate having the mixture of photoluminescence material and light reflective material homogeneously distributed throughout its volume.

14. The light emitting device of claim 1, wherein the particles of the light reflective material corresponds to a particle size such that the particles scatter excitation light generated by the solid-state light emitters relatively more than light generated by the at least one phosphor material.

15. The light emitting device of claim 1, further comprising a light diffusing layer that is adjacent to the photoluminescence wavelength conversion component.

16. The light emitting device of claim 15, in which the light diffusing layer comprises particles of light reflective material corresponding to a particle size such that the particles scatter excitation light generated by the solid-state light emitters relatively more than light generated by the at least one photoluminescence material.

17. The light emitting device of claim 16, wherein the light reflective material has a particle size in a range 100 nm to 150 nm.