Phosphor blends for green traffic signals

• US 20060091778A1
• Filed: 11/02/2004
• Published: 05/04/2006
• Est. Priority Date: 11/02/2004
• Status: Active Grant

• Current Assignee: Current Lighting Solutions, LLC (f/k/a GE Lighting Solutions, LLC) (American Industrial Partners)
• Original Assignee: Gelcore (General Electric Company)
• Inventors: Srivastava, Alok Mani, Weaver, Stanton Earl, Comanzo, Holly Ann, Setlur, Anant Achyut, Radkov, Emil Vergilov, Stecher, Thomas Elliot
• Granted Patent: US 7,321,191 B2
• Time in Patent Office: Days
• US Class Current: 313/486
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: C09K 11/7739 with halogens
• CPC Class Codes: C09K 11/774 Borates
• 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 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 2924/181 Encapsulation
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body

Abstract

There is provided a blue-green illumination system, including a semiconductor light emitter, and a luminescent material, wherein the system has an emission with CIE color coordinates located within an area of a of a pentagon on a CIE chromaticity diagram, whose corners have the following CIE color coordinates: i) x=0.0137 and y=0.4831; ii) x=0.2240 and y=0.3890; iii) x=0.2800 and y=0.4500; iv) x=0.2879 and y=0.5196; and v) x=0.0108 and y=0.7220. The luminescent material includes two or more phosphors. The illumination system may be used as the green light of a traffic light or an automotive display.

Claims

1. A blue-green illumination system, comprising a semiconductor light emitter;

and a luminescent material, wherein said illumination system has an emission having CIE color coordinates located within an area of a pentagon on a CIE chromaticity diagram, whose corners have the following CIE color coordinates;

e) x=0.0137 and y=0.4831;

b) x=0.2240 and y=0.3890;

c) x=0.2800 and y=0.4500;

g) x=0.2879 and y=0.5196; and

h) x=0.0108 and y=0.7220.

wherein said luminescent material comprises two or more phosphor compositions selected from the group consisting of;

(Ba,Sr,Ca)₅(PO₄)₃(Cl,F,Br,OH);

Eu²⁺;

(Ba,Sr,Ca)MgAl₁₀O₁₇;

Eu²⁺;

(Ba,Sr,Ca)BPO₅;

Eu²⁺;

(Sr,Ca)₁₀(PO₄)₆*nB₂O₃;

Eu²⁺;

2SrO*0.84P₂O₅*0.16B₂O₃;

Eu²⁺;

Sr₂Si₃O₈*2SrCl₂;

Eu²⁺;

Ba₃MgSi₂O₈;

Eu²⁺;

Sr₄Al₁₄O₂₅;

Eu²⁺;

BaAl₈O₁₃;

Eu²⁺;

(Ba,Sr,Ca)Al₂O₄;

Eu²⁺;

(Ba,Sr,Ca)Al<sub>2−

x</sub>Si_xO<sub>4−

x</sub>N_x;

Eu²⁺;

(Ba,Sr,Ca)₂SiO₄;

Eu²⁺;

(Ba,Sr,Ca)₂(Mg,Zn)Si₂O₇;

Eu²⁺;

(Sr,Ca,Ba)(Al,Ga,In)₂S₄;

Eu²⁺,Ce³⁺;

(Ca,Sr)₈(Mg,Zn)(SiO₄)₄Cl₂;

Eu²⁺;

(Y,Lu,Gd,Tb,Sc)₂(Ca,Mg)<sub>1−

r</sub>(Mg,Zn)_2+rSi<sub>z−

q</sub>Ge_qO_12+δ

;

Ce;

(Y,Gd,Tb,La,Sm,Pr,Lu)₃(Al,Ga)₅O₁₂;

Ce³⁺;

Sr—

SiON;

Eu²⁺, Ce³⁺;

MSi₃N₅, M₂Si₄N₇, M₄Si₆N₁₁, MgSi₁₁N₂₃, M₁₆Si₁₅O₆N₃₂, MSiAl₂O₃N₂, M₁₃Si₁₈Al₁₂O₁₈N₃₆, MSi₅Al₂ON₉ and M₃Si₅AlON₁₀ where M can be a divalent cation like Ca²⁺, Sr²⁺, Ba²⁺ or a trivalent cation like Y/Lu/Gd/Sc/Tb/La doped with Eu²⁺ and/or Ce³⁺; and

(Mg,Ca,Sr,Ba)_pSi_qAl_rO_xN_y, where 1≦

p≦

16;

0≦

q<

30;

0≦

r<

15, 0≦

x<

20 and 0<

y<

40 doped with Eu²⁺ and/or Ce³⁺.

2. The system of claim 1, wherein the light emitting diode peak emission wavelength is between 350 and 480 nm.

3. The system of claim 1, wherein the system'"'"'s emission CIE color coordinates are x=0.1±

0.05 and y=0.52±

0.05.

4. The system of claim 1, wherein the emission CIE color coordinates of the luminescent material are located within an area of a quadrilateral on a CIE chromaticity diagram, whose corners have the following CIE color coordinates:

a) x=0.000 and y=0.506;

b) x=0.224 and y=0.389;

c) x=0.280 and y=0.450; and

d) x=0.000 and y=0.730.

5. The system of claim 1, wherein the emission CIE color coordinates of the luminescent material are located within an area of a quadrilateral on a CIE chromaticity diagram, whose corners have the following CIE color coordinates:

e) x=0.0137 and y=0.4831;

f) x=0.2094 and y=0.3953;

g) x=0.2879 and y=0.5196; and

h) x=0.0108 and y=0.7220.

6. The system of claim 1, wherein said luminescent material comprises a blend of Sr₄Al₁₄O₂₅:

Eu²⁺ and at least one of (Ba,Sr,Ca)Al₂O₄;

Eu²⁺, (Sr,Ba)₂SiO₄;

Eu²⁺, or (Ca,Sr)₈(Mg,Zn)(SiO₄)₄Cl₂;

Eu²⁺.

7. The system of claim 1, wherein said luminescent material comprises a blend of Sr₄Al₁₄O₂₅:

Eu²⁺, SrAl₂O₄;

Eu²⁺ and Ca₈(SiO₄)₄Cl₂;

Eu²⁺.

8. The system of claim 1, wherein said luminescent material comprises a blend of SrAl₂O₄:

Eu²⁺ and Sr₄Al₁₄O₂₅;

Eu²⁺.

9. The system of claim 1, wherein said semiconductor light emitter comprises a light emitting diode.

10. The system of claim 9, further comprising:

a shell containing the light emitting diode;

an encapsulating material between the shell and the light emitting diode; and

wherein;

a) the phosphor is coated over a surface of the light emitting diode;

b) the phosphor is interspersed in the encapsulating material;

or

c) the phosphor is coated onto the shell.

11. The system of claim 1, further comprising a traffic signal housing containing the blue-green illumination system and a traffic light lens in front of the blue-green illumination system.

12. The system of claim 1, further comprising an automotive display containing the blue-green illumination system.

13. A traffic signal, comprising:

a housing;

at least one lens;

a radiation source having a peak emission wavelength of 480 nm or below; and

a luminescent material,

wherein said signal has an emission having CIE color coordinates located within an area of a quadrilateral on a CIE chromaticity diagram, whose corners have the following CIE color coordinates;

a) x=0.000 and y=0.506;

b) x=0.224 and y=0.389;

c) x=0.280 and y=0.45; and

d) x=0.000 and y=0.730.

wherein said luminescent material comprises two or more phosphor compositions selected from the group consisting of;

(Ba,Sr,Ca)₅(PO₄)₃(Cl,F,Br,OH);

Eu²⁺;

(Ba,Sr,Ca)MgAl₁₀O₁₇;

Eu²⁺;

(Ba,Sr,Ca)BPO₅;

Eu²⁺;

(Sr,Ca)₁₀(PO₄)₆*nB₂O₃;

Eu²⁺;

2SrO*0.84P₂O₅*0.16B₂O₃;

Eu²⁺;

Sr₂Si₃O₈.2SrCl₂;

Eu²⁺;

Ba₃MgSi₂O₈;

Eu²⁺;

Sr₄Al₁₄O₂₅;

Eu²⁺;

BaAl₈O₁₃;

Eu²⁺;

(Ba,Sr,Ca)Al₂O₄;

Eu²⁺;

(Ba,Sr,Ca)Al<sub>2−

x</sub>Si_xO<sub>4−

x</sub>N_x;

Eu²⁺;

(Ba,Sr,Ca)₂SiO₄;

Eu²⁺;

(Ba,Sr,Ca)₂(Mg,Zn)Si₂O₇;

Eu²⁺;

(Sr,Ca,Ba)(Al,Ga,In)₂S₄;

Eu²⁺,Ce³⁺;

(Ca,Sr)₈(Mg,Zn)(SiO₄)₄Cl₂;

Eu²⁺;

(Y,Lu,Gd,Tb,Sc)₂(Ca,Mg)<sub>1−

r</sub>(Mg,Zn)_2+rSi<sub>z−

q</sub>Ge_qO_12+δ

;

Ce;

(Y,Gd,Tb,La,Sm,Pr,Lu)₃(Al,Ga)₅O₁₂;

Ce³⁺;

Sr—

SiON;

Eu²⁺,Ce³⁺;

MSi₃N₅, M₂Si₄N₇, M₄Si₆N₁₁, M₉Si₁₁N₂₃, M₁₆Si₁₅O₆N₃₂, MSiAl₂O₃N₂, M₁₃Si₁₈Al₁₂O₁₈N₃₆, MSi₅Al₂ON₉ and M₃Si₅AlON₁₀ where M can be a divalent cation like Ca²⁺, Sr²⁺, Ba²⁺ or a trivalent cation like Y/Lu/Gd/Sc/Tb/La doped with Eu²⁺ and/or Ce³⁺; and

(Mg,Ca,Sr,Ba)_pSi_qAl_rO_xN_y, where 1≦

p≦

16;

0≦

q<

30;

0≦

r<

15, 0≦

x<

20 and 0<

y<

40 doped with Eu²⁺ and/or Ce³⁺.

14. The traffic signal of claim 13, wherein the radiation source comprises a light emitting diode or a fluorescent lamp.

15. The traffic signal of claim 13, wherein said luminescent material comprises a blend of Sr₄Al₁₄O₂₅:

Eu²⁺ and at least one of (Ba,Sr,Ca)Al₂O₄;

Eu²⁺, (Sr,Ba)₂SiO₄;

Eu²⁺, or (Ca,Sr)₈(Mg,Zn)(SiO₄)₄Cl₂;

Eu²⁺.

16. The traffic signal of claim 13, wherein said luminescent material comprises a blend of Sr₄Al₁₄O₂₅:

Eu²⁺, SrAl₂O₄;

Eu²⁺ and Ca₈(SiO₄)₄Cl₂;

Eu²⁺.

17. The traffic signal of claim 13, wherein said luminescent material comprises a blend of SrAl₂O₄:

Eu²⁺ and Sr₄Al₁₄O₂₅;

Eu²⁺.

18. A method of making a blue-green light illumination system, comprising:

mixing a plurality of starting powders to form a starting powder mixture;

firing the starting powder mixture to form a calcined-body;

converting the calcined body into a phosphor powder having emission CIE color coordinates located within an area of a pentagon on a CIE chromaticity diagram, whose corners have the following CIE color coordinates;

e) x=0.0137 and y=0.4831;

f) x=0.2240 and y=0.3890;

g) x=0.2800 and y=0.4500;

h) x=0.2879 and y=0.5196;

i) x=0.0108 and y=0.7220; and

placing the phosphor powder into the illumination system; and

placing a light emitting diode into the illumination system, wherein the phosphor powder comprises one or more phosphor compositions selected from the group consisting of;

(Ba,Sr,Ca)₅(PO₄)₃(Cl,F,Br,OH);

Eu²⁺;

(Ba,Sr,Ca)MgAl₁₀O₁₇;

Eu²⁺;

(Ba,Sr,Ca)BPO₅;

Eu²⁺;

(Sr,Ca)₁₀(PO₄)₆*nB₂O₃;

Eu²⁺;

2SrO*0.84P₂O₅*0.16B₂O₃;

Eu²⁺;

Sr₂Si₃O₈.2SrCl₂;

Eu²⁺;

Ba₃MgSi₂O₈;

Eu²⁺;

Sr₄Al₁₄O₂₅;

Eu²⁺;

BaAl₈O₁₃;

Eu²⁺;

(Ba,Sr,Ca)Al₂O₄;

Eu²⁺;

(Ba,Sr,Ca)Al<sub>2−

x</sub>Si_xO<sub>4−

x</sub>N_x;

Eu²⁺;

(Ba,Sr,Ca)₂SiO₄;

Eu²⁺;

(Ba,Sr,Ca)₂(Mg,Zn)Si₂O₇;

Eu²⁺;

(Sr,Ca,Ba)(Al,Ga,In)₂S₄;

Eu²⁺,Ce³⁺;

(Ca,Sr)₈(Mg,Zn)(SiO₄)₄Cl₂;

Eu²⁺;

(Y,Lu,Gd,Tb,Sc)₂(Ca,Mg)<sub>1−

r</sub>(Mg,Zn)_2+rSi<sub>z−

q</sub>Ge_qO_12+δ

;

Ce;

(Y,Gd,Tb,La,Sm,Pr,Lu)₃(Al,Ga)₅O₁₂;

Ce³⁺;

Sr—

SiON;

Eu²⁺,Ce³⁺;

MSi₃N₅, M₂Si₄N₇, M₄Si₆N₁₁, M₉Si₁₁N₂₃, M₁₆Si₁₅O₆N₃₂, MSiAl₂O₃N₂, M₁₃Si₁₈Al₁₂O₁₈N₃₆, MSi₅Al₂ON₉ and M₃Si₅AlON₁₀ where M can be a divalent cation like Ca²⁺, Sr²⁺, Ba²⁺ or a trivalent cation like Y/Lu/Gd/Sc/Tb/La doped with Eu²⁺ and/or Ce³⁺; and

(Mg,Ca,Sr,Ba)_pSi_qAl_rO_xN_y, where 1≦

p≦

16;

0≦

q<

30;

0≦

r<

15, 0≦

x<

20 and 0<

y<

40 doped with Eu²⁺ and/or Ce³⁺.

20. The method of claim 20, wherein phosphor powder comprises a blend of Sr₄Al₁₄O₂₅:

Eu²⁺ and at least one of (Ba,Sr,Ca)Al₂O₄;

Eu²⁺, (Sr,Ba)₂SiO₄;

Eu²⁺, or (Ca,Sr)₈(Mg,Zn)(SiO₄)₄Cl₂;

Eu²⁺.

19. The method of claim 20, wherein the light emitting diode peak emission wavelength is between 350 and 480 nm.

21. The method of claim 20, wherein phosphor powder comprises a blend of Sr₄Al₁₄O₂₅:

Eu²⁺, SrAl₂O₄;

Eu²⁺ and Ca₈(SiO₄)₄Cl₂;

Eu²⁺.

22. The method of claim 20, wherein phosphor powder comprises a blend of SrAl₂O₄:

Eu²⁺ and Sr₄Al₁₄O₂₅;

Eu²⁺.

23. The method of claim 20, further comprising placing the light emitting diode into a shell;

and filling the shell with an encapsulating material.

24. The method of claim 23, further comprising:

a) coating a suspension of the phosphor powder and a solvent over a surface of the light emitting diode and drying the suspension;

b) interspersing the phosphor powder in the encapsulating material;

or

c) coating a suspension of phosphor powder and a solvent onto the shell and drying the suspension.

25. The method of claim 20, wherein the emission CIE color coordinates of the lighting device is located within an area of a quadrilateral on a CIE chromaticity diagram, whose corners have the following CIE color coordinates:

a) x=0.000 and y=0.506;

b) x=0.224 and y=0.389;

c) x=0.280 and y=0.450; and

d) x=0.000 and y=0.730.

26. The method of claim 20, further comprising placing the illumination system into a traffic signal housing.

27. The method of claim 20, wherein the emission CIE color coordinates of the phosphor are located within an area of a quadrilateral on a CIE chromaticity diagram, whose corners have the following CIE color coordinates:

e) x=0.0137 and y=0.4831;

f) x=0.2094 and y=0.3953;

g) x=0.2879 and y=0.5196; and

h) x=0.0108 and y=0.7220.