METAL SILICATE HALIDE PHOSPHORS AND LED LIGHTING DEVICES USING THE SAME

• US 20080128679A1
• Filed: 09/28/2007
• Published: 06/05/2008
• Est. Priority Date: 10/03/2006
• Status: Active Grant

• Current Assignee: Lightscape Materials, Inc. (DuPont de Nemours, Inc.)
• Original Assignee: Lightscape Materials, Inc. (DuPont de Nemours, Inc.)
• Inventors: Sides, Alison, Tian, Yongchi, Zakharov, Olga
• Granted Patent: US 7,713,442 B2
• Time in Patent Office: Days
• US Class Current: 257/14
• CPC Class Codes: C09K 11/77342 Silicates
• 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 2224/8592 Applying permanent coating, e.g. protective coating
• 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 33/502 Wavelength conversion materials

Abstract

The present invention relates to metal silicate halide (halosilicate) phosphors, the phosphors with an oxide coating, methods of making the phosphors, and light emitting diode- (LED-) based lighting devices modified with the phosphors.

Claims

1. ) A phosphor having a formula of (M1_x,M2_1-x)₆(SiO₄)₂X₄:

A, wherein;

M2 are each independently at least one metal ion selected from the group consisting of Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Zn²⁺ and Cd²⁺;

x is a value from about 0.001 to about 1;

X is at least one halide ion in ionic form; and

A is at least one activator ion selected from the group consisting of Eu²⁺, Yb²⁺, Mn²⁺, Bi³⁺, Pb²⁺, Ce³⁺, Nd³⁺, Pr³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, Tm³⁺ and Yb³⁺.

2. ) The phosphor of claim 1, wherein:

M1 and M2 are each independently Ca²⁺, Sr²⁺, Ba²⁺ or a combination thereof;

X is fluoride, chloride, bromide or a combination thereof; and

A is Eu²⁺, Mn²⁺, Ce³⁺ or combination thereof.

3. ) The phosphor of claim 1, wherein:

M1 is Sr²⁺;

M2 is Ca²⁺, Ba²⁺ or a combination thereof;

X is fluoride, chloride or a combination thereof; and

A is Eu²⁺, Mn²⁺, Ce³⁺ or a combination thereof.

4. ) The phosphor of claim 1, wherein the phosphor has the formula:

(Sr_x, Ca_1-x)₆(SiO₄)₂Cl₄;

Eu²⁺.

5. ) The phosphor of claim 4, wherein:

x is a value from about 0.01 to about 1; and

Eu²⁺ is of an amount from about 0.0001 mole to about 0.1 mole of the phosphor.

6. ) A coated phosphor comprising:

a) a phosphor according to claim 1;

b) at least one layer of a coating on the phosphor, wherein the layer comprises at least one oxide.

7. ) The coated phosphor of claim 6, wherein the coating comprises at least two layers.

8. ) A lighting device comprising:

a) a light source that emits light at wavelengths of at least about 300 nm; and

b) at least one phosphor according to claim 1, wherein;

(1) the phosphor is capable of absorbing at least a portion of the light emitted from the light source;

(2) the phosphor modifies a chromaticity of the portion of the light absorbed from the light source;

(3) the phosphor emits light of a longer wavelength than that of the light absorbed from the light source; and

(4) optionally, the phosphor further comprises at least one layer of a coating that comprises at least one oxide.

9. ) The lighting device of claim 8, wherein the lighting device produces white light.

10. ) The lighting device of claim 8, wherein the light source is a light emitting diode (LED).

11. ) The lighting device of claim 10, wherein:

the LED comprises a quantum well structure having a light emitting layer sandwiched between a p-type clad layer and an n-type clad layer.

12. ) The lighting device of claim 11, wherein:

the p-type clad layer is formed of Al_qGa_1-qN, wherein 0<

q<

1;

the n-type clad layer is formed of Al_rGa_1-rN, wherein 0≦

r<

1; and

optionally, the p-type clad layer has a band gap that is larger than the band gap of the n-type clad layer.

13. ) The lighting device of claim 12, wherein the LED comprises a light emitting layer containing indium and at least one quantum well structure.

14. ) The lighting device of claim 13, wherein:

optionally, at least one quantum well structure comprises at least one well layer of InGaN and at least one barrier layer of GaN;

optionally, at least one quantum well structure comprises at least one well layer of InGaN and at least one barrier layer of AlGaN; and

optionally, at least one quantum well structure comprises at least one well layer of AlInGaN and at least one barrier layer of AlInGaN;

wherein at least one barrier layer has a band gap energy larger than a band gap energy of at least one well layer and optionally, the well layer has a thickness of at most about 100 angstroms.

15. ) The lighting device of claim 8, wherein for the at least one phosphor:

M1 and M2 are each independently Ca²⁺, S²⁺, Ba²⁺ or a combination thereof;

X is fluoride, chloride, bromide or a combination thereof; and

A is Eu²⁺, Mn²⁺, Ce³⁺ or a combination thereof.

16. ) The light device of claim 8, wherein for the at least one phosphor:

M1 is Sr⁺;

M2 is Ca²⁺, Ba²⁺ or a combination thereof;

X is fluoride, chloride or a combination thereof; and

A is Eu²⁺, Mn²⁺, Ce³⁺ or a combination thereof.

17. ) The lighting device of claim 8, wherein the at least one phosphor has the formula (Sr_x,Ca_1-x)₆(SiO₄)₂Cl₄:

Eu²⁺.

18. ) The lighting device of claim 17, wherein:

x is a value from about 0.01 to about 1; and

Eu²⁺ is of an amount from about 0.0001 mole to about 0.1 mole of the phosphor.

19. ) The lighting device of claim 8, further comprising at least one additional phosphor having formula (I):

CaSiO_3′

(SiO₂)_n;

Rε

, Y 

 

(I)

wherein;

Rε

is at least one activator ion selected from the group consisting of Eu²⁺ and Mn²⁺; and

Y is at least one halide ion in ionic or atomic form or is absent.

20. ) The lighting device of claim 19, wherein the at least one additional phosphor comprises formula (II):

CaSiO_3′

(SiO₂)_n;

Eu²⁺, I 

 

(II)

and the additional phosphor emits blue light.

21. ) The lighting device of claim 20, wherein the at least one additional phosphor comprises formula (III):

CaSiO_3′

(SiO₂)_n;

Eu²⁺,Mn²⁺, I⁻

 

 

(III)

and the additional phosphor emits red light.

22. ) The lighting device of claim 21, further comprising at least two additional phosphors, wherein:

one phosphor comprises formula (II);

CaSiO_3′

(SiO₂)_n;

Eu²⁺, I⁻

; and

 

 

(II)

the second phosphor comprises formula (III);

CaSiO_3′

(SiO₂)_n;

Eu²⁺,Mn²⁺, I⁻

 

 

(III).

23. ) The lighting device of claim 8, further comprising at least one additional phosphor having further comprises at least one additional phosphor having a formula selected from:

(M1_xM2_1-x)₂LiSiO₄X;

A;

 

 

(a)

(M1_xM2_1-x)₅SiO₄X₆;

A;

 

 

(b)

(M1_xM2_1-x)₃SiO₄X₂;

A;

 

 

(c)

(M1_xM2_1-x)₅(SiO₄)₂X₂;

A;

 

 

(d)

(M1_xM2_1-x)₅Si₂O₇X₄;

A;

 

 

(e)

(M1_xM2_1-x)₁₀(Si₂O₇)₃X₂;

A;

 

 

(f)

(M1_xM2_1-x)₄Si₂O₇X₂;

A;

 

 

(g)

M1₆M2₄(Si₂O₇)₃X₂;

A;

 

 

(h)

(M1_xM2_1-x)₇Si₂O₇X₈;

A;

 

 

(i)

(M1_xM2_1-x)₄Si₃O₈X₂;

A;

 

 

(j)

(M1_xM2_1-x)₄Si₃O₈X₄;

A;

 

 

(k)

(M1_xM2_1-x)₈Si₄O₁₂X₈;

A;

 

 

(l)

(M1_xM2_1-x)₅Si₂O₆X₆;

A;

 

 

(m)

(M1_xM2_1-x)₁₅Si₆O₁₈X₈;

A;

 

 

(n)

(M1_xM2_1-x)₅Si₄O₁₀X₅;

A;

 

 

(o)

(M1_xM2_1-x)₁₀(SiO₄)₃(SO₄)₃X₂;

A;

 

 

(p)

(M1_xM2_1-x)₄(SiO₄)(SO₄)X₂;

A; and

 

 

(q)

(M1_xM2_1-x)₈Mg(SiO₄)₄X₂;

A, 

 

(r)

where;

M1 and M2 are each independently at least one metal ion selected from the group consisting of Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Zn²⁺ and Cd²⁺;

x is a value from about 0.001 to about 1;

X is at least one halide ion in ionic form;

A is at least one activator ion selected from the group consisting of Eu²⁺, Yb²⁺, Mn²⁺, Bi³⁺, Pb²⁺, Ce³⁺, Nd³⁺, Pr³⁺, Sm³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, Tm³⁺ and Yb³⁺;

if the phosphor has the formula (M1_xM2_1-x)₂LiSiO₄X;

A, and M1 is Sr²⁺, x is 1 and X is fluoride or M2 is Sr²⁺, x is 0 and X is fluoride, then A is not Eu²⁺; and

if the phosphor has the formula (M1_xM2_1-x)₃SiO₄X₂;

A, and M1 is Ca²⁺, x is 1 and X is chloride or M2 is Ca²⁺, x is 0 and X is chloride, then A is not Eu²⁺; and

if the phosphor has the formula (M_1-xM2_1-x)₈Mg(SiO₄)₄X₂;

A, and M1 is Ca²⁺, x is 1 and X is chloride or M2 is Ca²⁺, x is 0 and X is chloride, then A is not Eu²⁺.

24. ) The lighting device of claim 8, wherein the lighting device emits white light.

25. ) A lighting device comprising:

a) a light source that emits light at wavelengths of at least about 300 nm, wherein the light source is a light emitting diode (LED); and

b) at least one phosphor according to claim 1, wherein;

(1) the phosphor is capable of absorbing at least a portion of the light emitted from the light source;

(2) the phosphor modifies a chromaticity of the portion of the light absorbed from the light source;

(3) the phosphor emits light of a longer wavelength than that of the light absorbed from the light source; and

(4) optionally, the phosphor further comprises at least one layer of a coating that comprises at least one oxide,

wherein the lighting device produces white light.