White light emitting phosphor blend for LED devices

• US 7,267,785 B2
• Filed: 02/13/2006
• Issued: 09/11/2007
• Est. Priority Date: 05/15/2000
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Srivastava, Alok Mani, Comanzo, Holly Ann
• Primary Examiner(s): KOSLOW, CAROL M
• Application Number:
  US11/276,080
• Publication Number:
  US 20060113553A1
• Time in Patent Office: 575 Days
• Field of Search: 257/98, 257/100, 313/503, 438/27, 427/64, 427/157, 252/301.36, 252/301.4 P, 252/301.4 R, 252/301.4 H
• US Class Current: 252/301.36
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/7738 with alkaline earth metals
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

There is provided a white light illumination system including a radiation source, a first luminescent material having a peak emission wavelength of about 570 to about 620 nm, and a second luminescent material having a peak emission wavelength of about 480 to about 500 nm, which is different from the first luminescent material. The LED may be a UV LED and the luminescent materials may be a blend of two phosphors. The first phosphor may be an orange emitting Eu²⁺,Mn²⁺ doped strontium pyrophosphate, (Sr_0.8Eu_0.1Mn_0.1)₂P₂O₇. The second phosphor may be a blue-green emitting Eu²⁺ doped SAE, (Sr_0.90-0.99 Eu_0.01-0.1)₄Al₁₄O₂₅. A human observer perceives the combination of the orange and the blue-green phosphor emissions as white light.

Claims

1. A method of making a white light illumination system, comprising:

blending a first phosphor powder having a peak emission wavelength of about 570 to about 620 nm and a second phosphor powder having a peak emission wavelength of about 480 to about 500 nm to form a mixture; and

placing the mixture into the white light illumination system adjacent to an organic light emitting diode.

2. The method of claim 1, wherein the organic light emitting diode has an emission wavelength between 360 and 420 nm.

3. The method of claim 1, wherein the mixture further comprises an encapsulant or a binder.

4. The method of claim 1, wherein the second phosphor powder is at least one of:

a) A₄D₁₄O₂₅;

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg, and D comprises at least one of Al or Ga;

b) (2AO*0.84P₂O₅*0.16B₂O₃);

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg;

c) AD₈O₁₃;

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg, and D comprises at least one of Al or Ga;

d) A₁₀(P0₄)₆Cl₂;

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg;

or

e) A₂Si₃O₈*2ACl₂;

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg.

5. The method of claim 1, wherein the first phosphor powder comprises (A_1-x-yEu_xMn_y)₂P₂O₇ phosphor or A₃P₂O₈:

Eu²⁺,Mn²⁺ phosphor, wherein A comprises at least one of Sr, Ca, Ba or Mg and wherein 0<

x≦

0.2, and 0<

y≦

0.2.

6. A white light illumination system, comprising

a first phosphor powder having a peak emission wavelength of about 570 to about 620 nm;

a second phosphor powder having a peak emission wavelength of about 480 to about 500 nm and

an organic light emitting diode.

7. The system of claim 6, wherein the organic light emitting diode has an emission wavelength between 360 and 420 nm.

8. The system of claim 6, further comprising an encapsulant or a binder.

9. The system of claim 6, wherein the second phosphor powder is at least one of:

a) A₄D₁₄O₂₅;

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg, and D comprises at least one of Al or Ga;

b) (2AO*0.84P₂O₅*0.16B₂O₃);

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg;

c) AD₈O₁₃;

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg, and D comprises at least one of Al or Ga;

d) A₁₀(PO₄)₆Cl₂;

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg;

or

e) A₂Si₃O₈*2ACl₂;

Eu²⁺, wherein A comprises at least one of Sr, Ca, Ba or Mg.

10. The system of claim 6, wherein the first phosphor powder comprises (A_1-x-yEu_xMn_y)₂P₂O₇ phosphor or A₃P₂O₈:

Eu²⁺,Mn²⁺ phosphor, wherein A comprises at least one of Sr, Ca, Ba or Mg and wherein 0<

x≦

0.2, and 0<

y≦

0.2.