Tri-color white light led lamp

• US 20050200271A1
• Filed: 03/21/2003
• Published: 09/15/2005
• Est. Priority Date: 03/25/2002
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Muller-Mach, Regina B., Muller, Gerd O., Schmidt, Peter J., Juestel, Thomas, Mayr, Walter
• Granted Patent: US 7,642,708 B2
• Time in Patent Office: Days
• US Class Current: 313/503
• CPC Class Codes: C09K 11/7718 with alkaline earth metals
• CPC Class Codes: C09K 11/7728 containing europium
• CPC Class Codes: C09K 11/7729 Chalcogenides
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/77347 Silicon Nitrides or Silicon Oxynitrides
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• 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

The invention relates to a tri-color lamp for generating white light comprising a phosphor composition comprising a phosphor of general formula (Ba_1-x-y-z-Sr_xCa_y)₂SiO₄:Eu_z, wherein 0≦x≦1, 0≦y≦1 and 0<z<1. The phosphor composition may also comprise a red phosphor. The two phosphors can absorb radiation emitted by a light emitting diode, particularly a blue LED. This arrangement provides a mixing of three light sources—light emitted from the two phosphors and unabsorbed light from the LED. The invention also relates to an alternative to a green LED comprising a single green phosphor of general formula (Ba_1-x-y-z-Sr_xCa_y)₂SiO₄:Eu_z, wherein 0≦x≦1, 0≦y≦1 and 0<z<1, that absorbs radiation from a blue LED. A resulting device provides green light of high absorption efficiency and high luminous equivalent values.

Claims

1. A light emitting device comprising a LED for emitting a pattern of light and a phosphor composition comprising a phosphor of general formula

(Ba_1-x-y-zSr_xCa_y)₂SiO₄:

Eu_z, wherein 0≦

x≦

1, 0≦

y≦

1 and 0<

z<

1.

2. The light emitting device according to claim 1, wherein the light emitting device has an emission at a wavelength from 450 nm to 480 nm.

4. The light emitting device according to claim 1, wherein the LED is a blue-emitting LED.

5. The light emitting device according to claim 1, wherein the phosphor composition comprises a green phosphor of general formula (Ba_1-x-y-zSr_xCa_y)₂SiO₄:

Eu_z, wherein 0≦

x≦

1, 0≦

y≦

1 and 0<

z<

1 and a red phosphor.

6. The light emitting device according to claim 5, wherein the red phosphor is selected from the group of (Sr_1-x-yBa_xCa_y)S:

Eu wherein 0≦

x<

1 and 0<

y≦

1;

CaS;

Ce,Cl;

Li₂Sr SiO₄;

Eu;

(Sr_1-xCa_x)SiO₄;

Eu wherein 0≦

x<

1;

(Y_1-xGd_x)₃(Al_1-yGa_y)₅O₁₂;

Ce wherein 0≦

x<

1 and 0≦

y<

1 and (Sr_1-x-yBa_xCa_y)₂Si₅N₈;

Eu wherein 0≦

x<

1 and 0≦

y<

1.

7. The light emitting device according to claim 1, wherein the device is a lamp.

8. The light emitting device according to claim 1, wherein the device is a traffic sign.

3. The light emitting device according to claim, wherein the phosphor composition is comprised in a thin film layer.

9. A phosphor composition comprising a phosphor of general formula (Ba_1-x-y-zSr_xCa_y)₂SiO₄:

Eu_z, wherein 0 x 1, 0 y 1 and 0<

z<

1.