PERSISTENT PHOSPHOR

• US 20090152497A1
• Filed: 12/12/2007
• Published: 06/18/2009
• Est. Priority Date: 12/12/2007
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Loureiro, Sergio Paulo, Srivastava, Alok Mani, Stoklosa, Stanley John, Comanzo, Holly Ann, Setlur, Anant Achyut, Henderson, Claire S., Beers, William W.
• Granted Patent: US 7,959,827 B2
• Time in Patent Office: Days
• US Class Current: 252/301.60R
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/7792 Aluminates

Abstract

A long-lived phosphor composition is provided, along with methods for making and using the composition. More specifically, in one embodiment, the phosphor comprises a material having a formula of A_x-y-zAl_2-m-n-o-pO₄:Eu_y, RE_z, B_m, Zn_n, Co_o, Sc_p. In this formula, A may be Ba, Sr, Ca, or a combination of these metals, x is between about 0.75 and 1.3, y is between about 0.0005 and 0.1, z is between about 0.0005 and 0.1, m is between about 0.0005 and 0.30, n is between about 0.0005 and 0.10, o is between about 0 and 0.01 and p is between about 0 and 0.05. RE is Dy, Nd, or a combination thereof. In another embodiment, methods are provided for making persistent phosphors comprising the formulations above. Other embodiments provide applications for such a phosphor, comprising uses in toys, emergency equipment, clothing, and instrument panels, among others.

Claims

1. A material comprising a phosphor comprising a general formula of A_x-y-zAl_2-m-n-o-pO₄:

Eu_y, RE_z, B_m, Zn_n, Co_o, Sc_p wherein;

A may be Ba, Sr, Ca, or a combination of these metals;

x is between about 0.75 and 1.3;

y is between about 0.0005 and 0.1;

z is between about 0.0005 and 0.1;

m is between about 0.0005 and 0.30;

n is between about 0.0005 and 0.10;

o is between about 0 and 0.01;

p is between about 0 and 0.05; and

RE is Dy, Nd, or a combination thereof.

2. The material of claim 1, wherein the phosphor has the formula:

Ca_0.932Eu_0.005Nd_0.03Al₂O₄Co_0.005.

3. The material of claim 1, wherein the phosphor has the formula Sr_0.9595Eu_0.01Dy_0.03Al_1.89Sc_0.01B_0.1O₄Co_0.005.

4. A method for producing a phosphor, the method comprising:

providing amounts of oxygen-containing compounds of europium, RE, and at least one alkaline-earth metal selected from the group consisting of Ba, Sr, Ca, and combinations thereof, wherein RE is at least one of neodymium or dysprosium;

mixing together the oxygen-containing compounds to form a mixture; and

then firing the mixture at a temperature between about 900°

C. and about 1700°

C. under a reducing atmosphere for a sufficient period of time to convert the mixture to a phosphor comprising a general formula of A_x-y-zAl_2-m-n-o-pO₄;

Eu_y, RE_z, B_m, Zn_n, Co_o, Sc_p wherein;

A may be Ba, Sr, Ca, or a combination of these metals;

x is between about 0.75 and 1.3;

y is between about 0.0005 and 0.1;

z is between about 0.0005 and 0.1;

m is between about 0.0005 and 0.30;

n is between about 0.0005 and 0.10;

o is between about 0 and 0.01;

p is between about 0 and 0.05; and

RE is Dy, Nd, or a combination thereof.

5. The method according to claim 4, wherein the oxygen-containing compounds are selected from the group consisting of oxides, carbonates, nitrates, sulfates, phosphates, citrates, carboxylates, and combinations thereof.

6. An article of manufacture containing a phosphor, comprising:

a structure; and

a phosphor comprising a general formula of A_x-y-zAl_2-m-n-o-pO₄;

Eu_y, RE_z, B_m, Zn_n, Co_o, Sc_p wherein;

A may be Ba, Sr, Ca, or a combination of these metals;

x is between about 0.75 and 1.3;

y is between about 0.0005 and 0.1;

z is between about 0.0005 and 0.1;

m is between about 0.0005 and 0.30;

n is between about 0.0005 and 0.10;

o is between about 0 and 0.01;

p is between about 0 and 0.05; and

RE is Dy, Nd, or a combination thereof.

7. The article of manufacture of claim 6, wherein the structure is selected from the group consisting of safety equipment, toys, input devices, signs, emergency exit indicators, instrument panel controls, electrical switches, circuit breaker switches, furniture, communication devices, wristwatch faces, numbers on a wristwatch face, clock faces, numbers on a clock face, kitchen ware, utensils, labels, car dashboard controls, stair treads, clothing, lamps, weapon sights, and displays.

8. The article of manufacture of claim 6, wherein the phosphor is incorporated into the material of the structure.

9. The article of manufacture of claim 6, wherein the phosphor is incorporated into a film attached to the structure.

10. The article of manufacture of claim 6, wherein the phosphor is incorporated into a paint composition applied to the structure.

11. The article of manufacture of claim 6, wherein the structure comprises a thermo-plastic matrix selected from the group consisting of polystyrene, high impact polystyrene (HIPS), styrene-butadiene copolymer, polycarbonate, polyethylene, polyurethane, polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), polypropylene, and combinations thereof.

12. The article of manufacture of claim 6, wherein the structure comprises a thermo-set plastic matrix selected from the group consisting of silicone RTV resin, epoxy resin, polyester, phenol-formaldehyde resin, melamine, and combinations thereof.

13. The article of manufacture of claim 6, wherein the structure comprises a glass, a ceramic, or a combination thereof.

14. A method for making nano-scale particles of an oxide based phosphor, comprising:

forming a first micro-emulsion;

forming a second micro-emulsion;

mixing the first and the second micro-emulsion to form a solution;

isolating precursor particles from the solution; and

forming nano-scale particles of the oxide based phosphor from the precursor particles;

wherein the oxide based phosphor comprises a general formula of A_x-y-zAl_2-m-n-o-pO₄;

Eu_y, RE_z, B_m, Zn_n, Co_o, Sc_p wherein;

A may be Ba, Sr, Ca, or a combination of these metals;

x is between about 0.75 and 1.3;

y is between about 0.0005 and 0.1;

z is between about 0.0005 and 0.1;

m is between about 0.0005 and 0.30;

n is between about 0.0005 and 0.10;

o is between about 0 and 0.01;

p is between about 0 and 0.05; and

RE is Dy, Nd, or a combination thereof.

15. The method of claim 14 wherein forming the nano-scale particles of an oxide based phosphor from the precursor particles comprises firing the precursor particles.

16. The method of claim 14 wherein the oxide based phosphor comprises at least one phosphor having a formula of Ca_0.932Eu_0.005Nd_0.03Al₂O₄Co_0.005, Sr_0.9595Eu_0.01Dy_0.03Al_1.89Sc_0.01B_0.1O₄Co_0.005, or a combination thereof.

17. The method of claim 14 wherein the nano-scale particles of the oxide based phosphor are between about 50 and 900 nm in size.

18. A method for making nano-scale particles of an oxide based phosphor, comprising:

forming an organic metal solution;

forming a first micro-emulsion;

heating the organic metal solution, and slowly adding the organic metal solution to the first micro-emulsion to form a second micro-emulsion;

isolating precursor particles from the second micro-emulsion solution; and

forming nano-scale particles of the oxide based phosphor from the precursor particles, wherein the oxide based phosphor comprises a general formula of A_x-y-zAl_2-m-n-o-pO₄;

Eu_y, RE_z, B_m, Zn_n, Co_o, Sc_p wherein;

A may be Ba, Sr, Ca, or a combination of these metals;

x is between about 0.75 and 1.3;

y is between about 0.0005 and 0.1;

z is between about 0.0005 and 0.1;

m is between about 0.0005 and 0.30;

n is between about 0.0005 and 0.10;

o is between about 0 and 0.01;

p is between about 0 and 0.05; and

RE is Dy, Nd, or a combination thereof.

19. The method of claim 18 wherein forming the nano-scale particles of an oxide based phosphor from the precursor particles comprises firing the precursor particles.

20. The method of claim 18 wherein the oxide based phosphor comprises at least one phosphor having a general formula of Ca_0.932Eu_0.005Nd_0.03Al₂O₄Co_0.005, Sr_0.9595Eu_0.01Dy_0.03Al_1.89Sc_0.01B_0.1O₄Co_0.005, or a combination thereof.

21. The method of claim 18 wherein the nano-scale particles of the oxide based phosphor are between about 100 and 900 nm in size.