White light LED devices with flat spectra

• US 20070235751A1
• Filed: 06/04/2007
• Published: 10/11/2007
• Est. Priority Date: 06/24/2003
• Status: Active Grant

• Current Assignee: Current Lighting Solutions, LLC (f/k/a GE Lighting Solutions, LLC) (American Industrial Partners)
• Original Assignee: Lumination LLC
• Inventors: Radkov, Emil, Setlur, Anant, Hausmann, Ilona, Goodin, Marisa
• Granted Patent: US 7,646,032 B2
• Time in Patent Office: Days
• US Class Current: 257/103
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/7739 with halogens
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A light emitting apparatus including a phosphor blend including two or more phosphors to provide an emission spectrum simulating the spectral power distribution of a CIE reference illuminant across at least a certain spectral range. Such an apparatus is particularly suited for color-critical applications.

Claims

1. a lighting device for emitting white light comprising:

a light source emitting radiation having a peak emission in the range from about 350 nm to about 430 nm; and

a phosphor material radiationally coupled to the light source, wherein an emission of the lighting device has an emission intensity conformance within ±

20% with a reference CIE illuminant at least in the spectral interval from 450 to 650 nm.

2. The lighting device of claim 1, wherein the light source comprises one of an LED and an organic emissive structure.

3. The lighting device of claim 2, further comprising an encapsulant surrounding the light source.

4. The lighting device of claim 3, wherein the phosphor material is dispersed in the encapsulant.

5. The lighting device of claim 1, further comprising a reflector cup.

6. The lighting device of claim 1, further including a pigment, filter or other absorber capable of absorbing radiation generated between 250 nm and 450 nm.

7. The lighting device of claim 1, wherein said phosphor material comprises a blend of no more than 5 phosphor compounds.

8. The lighting device of claim 1, wherein said lighting device has an emission intensity conformance within ±

10% with a reference CIE illuminant at least in the spectral interval from 450 to 650 nm.

9. The lighting device of claim 1, wherein said lighting device has an emission intensity conformance within ±

20% with a reference CIE illuminant at least in the spectral interval from 400 to 700 nm.

10. The lighting device of claim 1, wherein said reference illuminant is D65.

11. The lighting device of claim 1, further including scattering particles.

12. The lighting device of claim 1, wherein said lighting device has a general CRI (R_a) equal to or greater than 95.

13. A phosphor blend for use in the lighting device of claim 1, wherein the phosphor blend comprises at least three phosphor compositions.

14. A method for producing a lighting device, comprising:

providing a light source emitting radiation having a peak emission in the range from about 350 nm to about 430 nm; and

radiationally coupling a phosphor blend to the light source;

wherein said phosphor blend is obtained by i) providing a blue emitting phosphor material, a green emitting phosphor material and a red emitting phosphor material, and ii) blending said blue, green and red phosphor materials in appropriate quantities to form a blend having a color point having a desired pair of color coordinates for its combined plaque emission spectra on the 1931 CIE chromaticity diagram;

such that an emission of the lighting device has an emission intensity conformance within ±

20% with a reference CIE illuminant at least in the spectral interval from 450 to 650 nm.

15. The method of claim 14, wherein at least one of said blue, green, and red emitting phosphor materials is obtained by pre-blending two or more phosphors with similar peak wavelengths.

16. The method of claim 14, wherein said color point is within 0.005 and 0.020 units of the Planckian locus on the 1931 CIE diagram.

17. The method of claim 14, wherein no more than 5 individual phosphor compositions are used.

18. A lighting device for emitting white light comprising:

a light source emitting radiation having a peak emission in the range from about 350 nm to about 430 nm; and

a phosphor material radiationally coupled to the light source, wherein an emission of the lighting device has an emission intensity conformance within ±

10% with CIE illuminant E at least in the spectral region from 450 to 650 nm.

19. A lighting device for emitting white light comprising:

a light source emitting radiation having a peak emission in the range from about 250 nm to about 410 nm; and

a phosphor material radiationally coupled to the light source, wherein an emission of the lighting device has an emission conformance within an intensity range of ±

15% with a reference CIE illuminant at least in the spectral interval from 400 to 700 nm.

20. The lighting device of claim 19, wherein said lighting device has an emission intensity conformance at least 99% and within an intensity range of ±

10% with a reference CIE illuminant at least in the spectral interval from 400 to 700 nm.