Tri-color white light led lamp

• US 7,642,708 B2
• Filed: 03/21/2003
• Issued: 01/05/2010
• 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: Juestel, Thomas, Muller-Mach, Regina B., Muller, Gerd O., Schmidt, Peter J., Mayr, Walter
• Primary Examiner(s): Patel; Nimeshkumar D.
• Assistant Examiner(s): Perry; Anthony T
• Application Number:
  US10/508,455
• Publication Number:
  US 20050200271A1
• Time in Patent Office: 2,482 Days
• Field of Search: 313/503, 252/301.4 R
• 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 phosphor composition comprising a phosphor of formula (Ba_0.49Sr_0.49)₂SiO₄:

Eu_0.02.

2. A light emitting device comprising a LED for emitting a pattern of light and the phosphor composition of claim 1.

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

4. The light emitting device according to claim 2, wherein the phosphor composition is comprised in a thin film layer.

5. The light emitting device according to claim 2, wherein the LED is a blue light emitting LED.

6. The light emitting device according to claim 2, which further comprises a red Phosphor selected from the group of (Sr₁₋

x−

yBa_xCa_y)S;

Eu wherein 0≦

x<

1 and 0≦

y<

1;

CaS;

Ce,Cl;

Li₂Sr SiO₄;

Eu;

(Sr<sub>1−

x</sub>Ca_x)SiO₄;

Eu wherein 0≦

x<

1;

(Y<sub>1−

x</sub>Gd_x)₃(Al<sub>1−

y</sub>Ga_y)₅O₁₂;

Ce wherein 0≦

x<

1 and (Sr<sub>1−

x−

y</sub>Ba_xCa_y)₂Si₅N₈;

Eu wherein 0≦

x<

1 and 0≦

y<

1.