High efficiency alkaline earth metal thiogallate-based phosphors

• US 20040206936A1
• Filed: 04/13/2004
• Published: 10/21/2004
• Est. Priority Date: 04/21/2003
• Status: Active Grant

• Current Assignee: Lightscape Materials, Inc. (DuPont de Nemours, Inc.)
• Original Assignee: Sarnoff Corporation (SRI International, Inc.)
• Inventors: Tian, Yongchi, Zaremba, Diane, Yocom, Perry Niel
• Granted Patent: US 7,125,501 B2
• Time in Patent Office: Days
• US Class Current: 252/301.4S
• CPC Class Codes: C01G 15/006 Compounds containing, besides gallium, indium, or thallium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: C09K 11/7786 with alkaline earth metals

Abstract

Provided, among other things, is a strontium calcium thiogallate phosphor doped with divalent europium, and having the following formula:

Sr_1-xCa_xGa₂S₄:yEu²⁺.zGa₂S₃,

where x is 0.0001 to 1, y is a value defining sufficient Eu²⁺ to provide luminescent emission, and z is 0.0001 to 0.2 based on the mole amount of Sr_1-xCa_xGa₂S₄:yEu²⁺.

Claims

1. A strontium calcium thiogallate phosphor doped with divalent europium, and having the following formula:

Sr_1-xCa_xGa₂S₄;

yEu²⁺.zGa₂S₃,

where x is 0.0001 to 1, y is a value defining sufficient Eu²⁺ to provide luminescent emission, and z is 0.0001 to 0.2 based on the mole amount of Sr_1-xCa_xGa₂S₄;

yEu²⁺.

2. The phosphor of claim 1, wherein z is 0.001 to 0.2.

3. The phosphor of claim 1, wherein z is 0.001 to 0.1.

4. The phosphor of claim 1, wherein y is 0.001 to 0.1 based on the mole amount of Sr_1-xCa_xGa₂S₄.

5. The phosphor of claim 4, wherein y is 0.01 to 0.08

6. The phosphor of claim 4, wherein y is 0.01 to 0.04.

7. The phosphor of claim 1, wherein the phosphor has an emission peak of 535 nm to 560 nm.

8. The phosphor of claim 7, wherein the emission peak has a bandwidth of 50 nm or less under excitation with an emission source at 440 nm±

40 nm.