Solid state white light emitter and display using same

• US 7,615,795 B2
• Filed: 07/18/2003
• Issued: 11/10/2009
• Est. Priority Date: 03/26/1996
• Status: Expired due to Fees

• Current Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Baretz, Bruce, Tischler, Michael A.
• Primary Examiner(s): Fahmy, Wael
• Assistant Examiner(s): KALAM, ABUL
• Application Number:
  US10/623,198
• Publication Number:
  US 20040016938A1
• Time in Patent Office: 2,307 Days
• Field of Search: 257 81- 82, 257 94- 95, 257 98-100, 257/88, 257/E33.059, 257/E33.061
• US Class Current: 257/98
• 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 liquid crystal display comprising a back light structure including at least one LED/phosphor assembly in which the LED is energizable to emit radiation and the phosphor is arranged to be impinged by radiation from the LED so that the LED/phosphor assembly produces white light back light illumination for the liquid crystal display.

2. The liquid crystal display of claim 1, comprising an array of LED/phosphor assemblies arranged to produce white light back light illumination for the liquid crystal display.

3. The liquid crystal display of claim 1, comprising a plurality of LED/phosphor assemblies arranged in a regular pattern array for white light back light illumination of the liquid crystal display.

4. The liquid crystal display of claim 3, wherein individual LED/phosphor assemblies in said regular pattern array are selectively illuminable.

5. The liquid crystal display of claim 3, wherein LED/phosphor assemblies in said regular pattern array are controlled by a controller in response to user input.

6. The liquid crystal display of claim 3, wherein all LED/phosphor assemblies in said regular pattern array are arranged to be simultaneously illuminated.

7. The liquid crystal display of claim 1, wherein the LED is energizable to emit radiation with an emission maximum in a spectral range of the blue to ultraviolet spectrum.

8. The liquid crystal display of claim 1, wherein the phosphor in each LED/phosphor assembly comprises a material responsively emitting radiation in at least the green spectrum.

9. The liquid crystal display of claim 1, wherein the LED in each LED/phosphor assembly comprises a blue light LED.

10. The liquid crystal display of claim 1, wherein the white light back light illumination produced by each LED/phosphor assembly comprises primary radiation emission from the LED and secondary radiation emission from the phosphor.

11. The liquid crystal display of claim 1, wherein the LED in each LED/phosphor assembly comprises a material selected from the group consisting of:

gallium nitride;

indium gallium nitride;

aluminum gallium indium nitride;

aluminum gallium nitride; and

indium nitride.

12. The liquid crystal display of claim 1, further comprising electrical circuitry operatively coupled with the display, wherein each LED/phosphor assembly is operatively coupled with the electrical circuitry for producing the white light back light illumination.

13. The liquid crystal display of claim 12, comprising a power supply operatively coupled with said electrical circuitry.

14. The liquid crystal display of claim 1, wherein the phosphor in each LED/phosphor assembly comprises a material responsively emitting radiation in at least the red spectrum.

15. The liquid crystal display of claim 1, wherein the phosphor comprises a material responsively emitting radiation in at least the yellow spectrum.

16. The liquid crystal display of claim 1, comprising a multiplicity of LED/phosphor assemblies.