SOLID STATE WHITE LIGHT EMITTER AND DISPLAY USING SAME

• US 20080224598A1
• Filed: 06/01/2008
• Published: 09/18/2008
• Est. Priority Date: 03/26/1996
• Status: Active Grant

• Current Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Tischler, Michael A., Baretz, Bruce
• Granted Patent: US 9,698,313 B2
• Time in Patent Office: Days
• US Class Current: 313/503
• CPC Class Codes: G09F 13/04 Signs, boards or panels, illuminated from behind the insignia
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48139 with an intermediate bond, e.g. continuous wire daisy chain
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: Y02E 10/52 PV systems with concentrators

Abstract

A light emitting assembly comprising a solid state device coupleable with a power supply constructed and arranged to power the solid state device to emit from the solid state device a first, relatively shorter wavelength radiation, and a down-converting luminophoric medium arranged in receiving relationship to said first, relatively shorter wavelength radiation, and which in exposure to said first, relatively shorter wavelength radiation, is excited to responsively emit second, relatively longer wavelength radiation. In a specific embodiment, monochromatic blue or UV light output from a light-emitting diode is down-converted to white light by packaging the diode with fluorescent organic and/or inorganic fluorescers and phosphors in a polymeric matrix.

Claims

1. A method of obtaining a white light output of a desired chromatic character, said method including providing at least one LED die configured to emit light in a spectral range of the blue to ultraviolet spectrum, and selecting specific ones of a multiplicity of luminophoric materials to constitute a luminophoric medium producing a white light output of the desired chromatic character when the luminophoric medium interacts with emitted light from the at least one LED die.

2. The method of claim 1, wherein the luminophoric materials comprise phosphor materials.

3. The method of claim 1, wherein the selected luminophoric materials comprise a material responsibly emitting radiation in at least one of the green spectrum and the yellow spectrum.

4. The method of claim 1, wherein the luminophoric medium comprises a material selecting radiation in at least red, yellow and green spectral regions.

5. The method of claim 1, wherein the luminophoric medium comprises a phosphor material that is interactive with blue light from the at least one LED die to produce said white light output of the desired chromatic character.

6. The method of claim 1, wherein the luminophoric medium includes red emissive and yellow emissive species.

7. The method of claim 1, wherein the luminophoric medium includes at least one phosphor doped with cerium or europium.

8. The method of claim 1, wherein the luminophoric medium includes red, green and blue emissive centers.

9. The method of claim 1, wherein the luminophoric medium includes a red emissive center.

10. The method of claim 1, wherein multiple LED dies are provided.

11. A method according to claim 1, further comprising packaging said luminophoric medium and at least one LED die.

12. The method of claim 1, comprising fabricating a light emitting display including said luminophoric medium and at least one LED die.

13. The method of claim 12, comprising energizing said at least one LED die to generate said white light output of desired chromatic character for said display.

14. The method of claim 1, wherein the luminophoric medium includes red and green emissive centers.