Phosphors for light generation from light emitting semiconductors

• US 6,255,670 B1
• Filed: 05/26/2000
• Issued: 07/03/2001
• Est. Priority Date: 02/06/1998
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Srivastava, Alok Mani, Duggal, Anil Raj
• Primary Examiner(s): Tran, Minh Loan
• Application Number:
  US09/579,037
• Time in Patent Office: 403 Days
• Field of Search: 257/88, 257/89, 257/98, 257/99, 257/100, 313/501, 313/502, 313/503
• US Class Current: 257/89
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

The phosphor A₂DSi₂O₇:Eu²⁺, where A is at least one of Ba, Sr, Ca and D is Mg and Zn absorbs UV light, for example from an LED, and converts the UV light to green light. The phosphor can be combined with a red phosphor such as Y₂O₃:Eu³⁺,Bi³⁺ and one or more blue phosphors such as SECA ((Sr,Ba,Ca)₅(PO₄)₃Cl:Eu²⁺) and BAM (BaMg₂Al₁₆O₂₇:Eu²⁺) to produce white light. Also, a light emitting apparatus is disclosed which comprises at least one of a red, green and blue phosphor for absorbing and converting ultraviolet radiation from a light emitting semiconductor into visible light. A laser diode can be used to activate the phosphors to provide improved efficiency and brightness.

Claims

1. A composition of matter comprising Ba₂(Mg,Zn)Si₂O₇:

Eu²⁺.

2. A composition of matter comprising

(Ba_1-X-Y-Z,Ca_X,Sr_Y,Eu_Z)₂(Mg_1-W,Zn_W)Si₂O₇, wherein

X+Y+Z≦

1;

Z>

0; and

0.05≦

W≦

0.50.

3. The composition of claim 2, wherein

0.1≦ W≦

0.3.

4. The composition of claim 3, wherein

0.01≦

Z≦

0.1.

5. The composition of claim 2, wherein

X>

0.

6. The composition of claim 2, wherein

Y>

0.

7. A lighting apparatus comprising:

a semiconductor ultraviolet light source; and

a phosphor comprising;

(Ba_1-X-Y-Z,Ca_X,Sr_Y,Eu_Z)₂(Mg_1-W,Zn_W)Si₂O₇, wherein

X+Y+Z<

1;

Z>

0; and

0.05≦

W≦

0.5.

8. The lighting apparatus of claim 7, wherein the semiconductor ultraviolet light source comprises an LED.

9. The composition of claim 8, wherein

0.1≦ W≦

0.3.

10. The composition of claim 9, wherein

0.01≦

Z≦

0.1.

11. The lighting apparatus of claim 7, wherein the semiconductor ultraviolet light source comprises a laser diode.

12. The lighting apparatus of claim 7, further comprising a red emitting phosphor and a blue emitting phosphor.