BLUE-GREEN AND GREEN PHOSPHORS FOR LIGHTING APPLICATIONS

• US 20100096974A1
• Filed: 10/22/2008
• Published: 04/22/2010
• Est. Priority Date: 10/22/2008
• Status: Active Grant

• Current Assignee: Current Lighting Solutions, LLC (f/k/a GE Lighting Solutions, LLC) (American Industrial Partners)
• Original Assignee: General Electric Company
• Inventors: Chandran, Ramachandran Gopi, Nammalwar, Pransanth Kumar, Radkov, Emil, Setlur, Anant Achyut, Henderson, Claire Susan
• Granted Patent: US 8,329,060 B2
• Time in Patent Office: Days
• US Class Current: 313/487
• CPC Class Codes: C09K 11/7721 Aluminates
• CPC Class Codes: C09K 11/77214 Aluminosilicates
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/06102 the bonding areas being at different heights
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/181 Encapsulation
• 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

Embodiments of the present techniques provide a related family of phosphors that may be used in lighting systems to generate blue or blue-green light. The phosphors include systems having a general formula of: ((Sr_1−zM_z)_1−(x+w)A_wCe_x)₃(Al_1−ySi_y)O_4+y+3(x−w)F_{1−y−3(x−w)} (I), wherein 0<x≦0.10, 0≦y≦0.5, 0≦z≦0.5, 0≦w≦x, A is Li, Na, K, Rb, or Ag or any combinations thereof, and M is Ca, Ba, Mg, Zn, or Sn or any combinations thereof. Advantageously, phosphors made accordingly to these formulations maintain emission intensity across a wide range of temperatures. The phosphors may be used in lighting systems, such as LEDs and fluorescent tubes, among others, to produce blue and blue/green light. Further, the phosphors may be used in blends with other phosphors, or in combined lighting systems, to produce white light suitable for illumination.

Claims

1. A lighting apparatus comprising:

a light source configured to emit radiation with a peak intensity at a wavelength between about 250 nm and about 550 nm; and

a phosphor composition configured to be radiationally coupled to the light source, wherein the phosphor composition comprises a phosphor comprising a general formula of ((Sr<sub>1−

z</sub>M_z)<sub>1−

(x+w)</sub>A_wCe_x)₃(Al<sub>1−

y</sub>Si_y)O<sub>4+y+3 (x−

w)</sub>F<sub>1−

y−

3(x−

w)</sub>, wherein 0<

x≦

0.10, 0≦

y≦

0.5, 0≦

z≦

0.5, 0≦

w≦

x, A is Li, Na, K, Rb, or any combinations thereof, and M is Ca, Ba, Mg, Zn, or Sn or any combinations thereof.

2. The lighting apparatus of claim 1, wherein the light source is a semiconductor light emitting diode (LED).

3. The lighting apparatus of claim 2, wherein the LED comprises a nitride compound semiconductor represented by the formula In_iGa_jAl_kN, where 0≦

i;

0≦

j, 0≦

k, and i+j+k=1.

4. The lighting apparatus of claim 1, wherein the light source comprises a gas vapor discharge emitting light having a peak intensity at a wavelength between about 250 to about 400 nm.

5. The lighting apparatus of claim 1, wherein the phosphor composition is coated on the surface of the light source.

6. The lighting apparatus of claim 1, wherein the phosphor composition is dispersed in an encapsulant surrounding the light source and the phosphor composition.

7. The lighting apparatus of claim 1, wherein the phosphor composition comprises one or more additional phosphors.

8. The lighting apparatus of claim 7, wherein the one or more additional phosphors comprise:

a complex fluoride doped with Mn⁴⁺;

(Ba,Sr,Ca)₅(PO₄)₃(Cl,F,OH);

Eu²⁺;

Ca₂Si₅N₈;

Ce³⁺,Eu²⁺;

(Lu,Ca,Li,Mg,Y)_1.5Al₃Si₉N₁₆;

Eu²⁺,Ce³⁺;

or (Ba,Sr,Ca)₂Si<sub>1−

x</sub>O<sub>4−

2x</sub>;

Eu²⁺(wherein 0≦

x≦

0.2);

or any combinations thereof.

9. A phosphor comprising a general formula of ((Sr₁₋

zM_z)<sub>1−

(x+w)</sub>A_wCe_x)₃(Al<sub>1−

y</sub>Si_y)O<sub>4+y+3(x−

w)</sub>F<sub>1−

y−

3(x−

w)</sub>, wherein 0<

x≦

0.10, 0≦

y≦

0.5, 0≦

z≦

0.5, 0≦

w≦

x, A is Li, Na, K, or Rb, or any combinations thereof, and M is Ca, Ba, Mg, or Zn, or any combinations thereof.

10. The phosphor of claim 9, wherein at least a portion of the Al is replaced by B, Ga, Sc, or Y, or any combinations thereof.

11. The phosphor of claim 9, wherein at least a portion of the F is replaced by Cl, Br, or I, or any combinations thereof.

12. The phosphor of claim 9, wherein the phosphor is doped with another luminescent activator ion.

13. The phosphor of claim 12, wherein the additional luminescent activator ion is Pr, Sm, Eu, Tb, Dy, Tm, Er, Ho, Nd, Bi, Pb, Yb, Mn, Ag, or Cu, or any combinations thereof.

14. The phosphor of claim 9, wherein the phosphor comprises a solid solution with a second phosphor having a composition comprising (Ba,Ca,Sr)₃SiO₅, Sr₂(Gd,La,Y)AlO₅, or (La,Gd,Y)₃SiO₄N, or any combinations thereof.

15. The phosphor of claim 9, comprising a general formula of ((Sr₁₋

yM_y)<sub>1−

2x</sub>A_xCe_x)₃AlO₄F, wherein 0<

x≦

0.10, 0≦

y≦

0.5, A is Li, Na, K, or Rb, or any combinations thereof, and M is Ca, Ba, Mg, Zn, or Sn or any combinations thereof.

16. The phosphor of claim 9 comprising a general formula of ((Sr₁₋

zM_z)1−

xCe_x)₃(Al<sub>1−

y</sub>Si_y)O_4+y+3xF<sub>1−

y−

3x</sub>, wherein 0<

x≦

0.10 and 0≦

y≦

0.5, 0≦

z≦

0.5, and M is Ca, Ba, Mg, Zn, or Sn or any combinations thereof.

17. The phosphor of claim 9, wherein the phosphor has a quantum efficiency at about 150°

C. that is at least about 80% of the quantum efficiency at a temperature of between about 15°

C. and about 25°

C.

18. The phosphor of claim 9, wherein the phosphor has a quantum efficiency of at least about 90% of the quantum efficiency of the reference phosphor Sr₄Al₁₄O₂₅:

Eu²⁺ at a temperature of between about 15°

C. and about 25°

C.

19. The phosphor according to claim 9, comprising at least one of:

(Sr_0.98Na_0.01Ce_0.01)₃AlO₄F;

(Sr_0.98,Na_0.01Ce_0.01)(Al_0.9Si_0.1)O_4.1F_0.9;

(Sr_0.98,Na_0.01Ce_0.01)(Al_0.8Si_0.2)O_4.2F_0.8;

(Sr_0.75Ca_0.23Na_0.01Ce_0.01)(Al_0.75Si_0.25)O_4.25F_0.75, or

(Sr_0.595Ca_0.4Ce_0.005)(Al_0.6Si_0.4)O_4.415F_0.585.

20. A phosphor blend comprising:

a first phosphor comprising a general formula of ((Sr<sub>1−

z</sub>M_z)<sub>1−

(x+w)</sub>A_wCe_x)₃(Al<sub>1−

y</sub>Si_y)O<sub>4+y+3(x−

w)</sub>F<sub>1−

y−

3(x−

w)</sub>, wherein 0<

x≦

0.10, 0≦

y≦

0.5, 0≦

z≦

0.5, 0≦

w≦

x, A is Li, Na, K, or Rb, or any combinations thereof, and M is Ca, Ba, Mg, Zn, or Sn or any combinations thereof; and

at least one additional phosphor, wherein the phosphor blend is capable of emitting light suitable for use either alone or in combination with radiation emitted by a light source radiationally coupled to the phosphor.

21. The phosphor blend of claim 20, wherein the one or more additional phosphors comprise:

a complex fluoride doped with Mn⁴⁺;

(Ba,Sr,Ca)₅(PO₄)₃(Cl,F,OH);

Eu²⁺;

Ca₂Si₅N₈;

Ce³⁺,Eu²⁺;

(Lu,Ca,Li,Mg,Y)_1.5Al₃Si₉N₁₆;

Eu²⁺,Ce³⁺;

or (Ba,Sr,Ca)₂Si<sub>1−

x</sub>O<sub>4−

2x</sub>;

Eu²⁺ (wherein 0≦

x≦

0.2);

or any combinations thereof.

22. The phosphor blend of claim 20, wherein the one or more additional phosphors comprise:

Yellow (Ba,Sr,Ca)₅(PO₄)₃(Cl,F,Br,OH);

Eu²⁺,Mn²⁺;

(Ba,Sr,Ca)BPO₅;

Eu²⁺,Mn²⁺;

(Sr,Ca)₁₀(PO₄)₆*xB₂O₃;

Eu²⁺ (wherein 0<

x≦

1);

Sr₂Si₃O₈*2SrCl₂;

Eu²⁺;

(Ca,Sr,Ba)₃MgSi₂O₈;

Eu²⁺,Mn²⁺;

BaAl₈O₁₃;

Eu²⁺;

2SrO*0.84P₂O₅*0.16B₂O₃;

Eu²⁺;

(Ba,Sr,Ca)MgAl₁₀O₁₇;

Eu²⁺,Mn²⁺;

(Ba,Sr,Ca)Al₂O₄;

Eu²⁺;

(Y,Gd,Lu,Sc,La)BO₃;

Ce³⁺,Tb³⁺;

(Ba,Sr,Ca)₂Si<sub>1−

x</sub>O<sub>4−

2x</sub>;

Eu²⁺ (wherein 0≦

x≦

0.2) (SASI);

(Ba,Sr,Ca)₂(Mg,Zn)Si₂O₇;

Eu²⁺;

(Sr,Ca,Ba)(Al,Ga,In)₂S₄;

Eu²⁺;

(Y,Gd,Tb,La,Sm,Pr,Lu)₃(Sc,Al,Ga)<sub>5−

a</sub>O<sub>12−

3/2a</sub>;

Ce³⁺ (wherein 0≦

a≦

0.5);

(Lu,Sc,Y,Tb)<sub>2−

x−

y</sub>Ce_yCa_1+xLi_zMg<sub>2−

z</sub>P_z(Si,Ge)<sub>3−

z</sub>O<sub>12−

x/2</sub> (wherein 0.5≦

x≦

1, 0<

y≦

0.1, and 0≦

z≦

0.2);

(Ca,Ba,Sr)Si₂O₂N₂;

Eu²⁺,Ce³⁺;

(Ca,Sr)₈(Mg,Zn)(SiO₄)₄Cl₂;

Eu²⁺,Mn²⁺;

Na₂Gd₂B₂O₇;

Ce³⁺,Tb³⁺;

(Sr,Ca,Ba,Mg,Zn)₂P₂O₇;

Eu²⁺,Mn²⁺;

(Gd,Y,Lu,La)₂O₃;

Eu³⁺,Bi³⁺;

(Gd,Y,Lu,La)₂O₂S ;

Eu³⁺,Bi³⁺;

(Gd,Y,Lu,La)VO₄;

Eu³⁺,Bi³⁺;

(Ca,Sr)S;

Eu²⁺,Ce³⁺;

ZnS;

Cu⁺,Cl⁻

;

ZnS;

Cu⁺,Al³⁺;

ZnS;

Ag⁺,Cl⁻

;

ZnS;

Ag⁺,Al³⁺;

SrY₂S₄;

Eu²⁺;

CaLa₂S₄;

Ce³⁺;

(Ba,Sr,Ca)MgP₂O₇;

Eu²⁺,Mn²⁺;

(Y,Lu)₂WO₆;

Eu³⁺,Mo⁶⁺;

(Ba,Sr,Ca)_xSi_yN_z;

Eu²⁺,Ce³⁺ (wherein 2x+4y=3z);

Ca₃(SiO₄)Cl₂;

Eu²⁺;

(Y,Lu,Gd)<sub>2−

x</sub>Ca_xSi₄N_6+xC<sub>1−

x</sub>;

Ce³⁺, (wherein 0≦

x≦

0.5);

(Lu,Ca,Li,Mg,Y)alpha-SiAlON;

Eu²⁺,Ce³⁺;

3.5MgO*0.5MgF₂*GeO₂;

Mn⁴⁺ (Mg-fluorogermanate);

Ca<sub>1−

x−

y</sub>Ce_xEu_yAl_1+xSi<sub>1−

x</sub>N₃, (wherein 0<

x≦

0.2, 0≦

y≦

0.2);

Ca<sub>1−

x−

y</sub>Ce_xEu_yAl<sub>1−

x</sub>(Mg,Zn)_xSiN₃, (where 0<

x≦

0.2, 0≦

y≦

0.2);

Ca<sub>1−

2x−

y</sub>Ce_x(Li,Na)_xEu_yAlSiN_3, (where 0≦

x≦

0.2, 0≦

y≦

0.2, x+y>

0);

or Ca<sub>1−

x−

y</sub>Ce_x(Li,Na)_yEu_zAl<sub>1+x−

y</sub>Si<sub>1−

x+y</sub>N₃, (where 0≦

x≦

0.2, 0<

y≦

0.4, 0≦

z≦

0.2);

or any combinations thereof.

23. The phosphor blend of claim 20, wherein the light emitted by the blend alone or in combination with radiation emitted by a light source radiationally coupled to the phosphor is white, has a CRI of at least about 80, or both.

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

providing amounts of oxygen-containing compounds of cerium , silicon, and at least one alkaline-earth metal selected from the group consisting of Sr, Ba, Ca, and combinations thereof;

mixing together the oxygen-containing compounds with a fluoride containing compound 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 ((Sr<sub>1−

z</sub>M_z)<sub>1−

(x+w)</sub>A_wCe_x)₃(Al<sub>1−

y</sub>Si_y)O<sub>4+y+3(x−

w)</sub>F<sub>1−

y−

3(x−

w)</sub>, wherein 0<

x≦

0.10, 0≦

y≦

0.5, 0≦

z≦

0.5, 0≦

w≦

x, A is Li, Na, K, or Rb, or any combinations thereof, and M is Ca, Ba, Mg, Zn, or any combinations thereof.

25. The method according to claim 24, wherein the oxygen-containing compounds are selected from the group consisting of oxides, hydroxides, carbonates, nitrates, aluminates, silicates, citrates, oxalates, carboxylates, tartarates, stearates, and combinations thereof.