Metal silicate halide phosphors and LED lighting devices using the same

• US 8,906,262 B2
• Filed: 09/27/2006
• Issued: 12/09/2014
• Est. Priority Date: 12/02/2005
• Status: Expired due to Fees

• Current Assignee: Lightscape Materials, Inc. (DuPont de Nemours, Inc.)
• Original Assignee: Lightscape Materials, Inc. (DuPont de Nemours, Inc.)
• Inventors: Tian, Yongchi, Yocom, Perry Niel, Aziz, Sawsan, Zakharov, Olga, Sides, Alison
• Primary Examiner(s): Hoban, Matthew E
• Application Number:
  US11/527,835
• Publication Number:
  US 20070125982A1
• Time in Patent Office: 2,995 Days
• Field of Search: 252/301.4 H, 252/301.4 R, 252/301.4 S, 252/301.4 F, 313/503
• US Class Current: 252/301.4H
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• 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
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2993 Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]

Abstract

The present invention relates to certain 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 lighting device comprising:

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

b) at least one phosphor having a formula selected from the group consisting of;

1) (M1_xM2_1-x)₂LiSiO₄X;

A;

2) (M1_xM2_1-x)₁₀(SiO₄)₃(SO₄)₃X₂;

A; and

3) (M1_xM2_1-x)₄(SiO₄)(SO₄)X₂;

A;

wherein;

M1 and M2 are each independently at least one metal ion selected from the group consisting of Mg²⁺, Ca²⁺, Sr⁺, 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⁺, Pr²⁺, 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

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

the phosphor modifies a chromaticity of the portion of the light absorbed from the light source; and

the phosphor emits light of a longer wavelength than that of the light absorbed from the light source.

2. The lighting device of claim 1, wherein the lighting device produces white light.

3. The lighting device of claim 1, wherein the light source is a light emitting diode (LED).

4. The lighting device of claim 3, 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.

5. The lighting device of claim 4, wherein:

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

q<

1; and

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

r<

1.

6. The lighting device of claim 5, wherein the LED comprises a light emitting layer containing indium and at least one quantum well structure.

7. The lighting device of claim 6, wherein the at least one quantum well structure comprises:

(i) at least one well layer of InGaN and at least one barrier layer of GaN;

(ii) at least one well layer of InGaN and at least one barrier layer of AlGaN;

or

(iii) at least one well layer of AlInGaN and at least one barrier layer of AlInGaN;

wherein for each quantum well structure recited by (i), (ii), and (iii), at least one barrier layer has a band gap energy larger than a band gap energy of at least one well layer.

8. The lighting device of claim 1, wherein for the at least one phosphor:

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 a combination thereof.

9. The lighting device of claim 1, wherein for the at least one phosphor:

M1 is Ca²⁺;

M2 is Sr²⁺, Ba²⁺ or a combination thereof;

X is fluoride, chloride or a combination thereof; and

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

10. The lighting device of claim 1, further comprising at least one additional phosphor having formula (I):

CaSiO₃.(SiO₂)_n;

R∈

,Y 

 

(I)

wherein;

R∈

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.

11. The lighting device of claim 10, wherein the at least one additional phosphor comprises formula (II):

CaSiO₃.(SiO₂)_n;

Eu²⁺,I⁻

 

 

(II)

and the additional phosphor emits blue light.

12. The lighting device of claim 10, wherein the at least one additional phosphor comprises formula (III):

CaSiO₃.(SiO₂)_n;

Eu²⁺,Mn²⁺,I⁻

 

 

(III)

and the additional phosphor emits red light.

13. The lighting device of claim 10, further comprising at least two additional

phosphors, wherein:

one phosphor comprises formula (II);

CaSiO₃.(SiO₂)_n;

Eu²⁺,I⁻

 

 

(II)

the second phosphor comprises formula (III);

CaSiO₃.(SiO₂)_n;

Eu²⁺,Mn²⁺,I⁻

 

 

(III).

14. The lighting device of claim 13, wherein the lighting device emits white light.

16. The lighting device of claim 1, wherein the phosphor further comprises at least one layer of a coating that comprises at least one oxide.

18. The lighting device of claim 5, wherein the p-type clad layer has a band gap that is larger than the band gap of the n-type clad layer.

19. The lighting device of claim 7, wherein the well layer has a thickness of at most about 100 angstroms.

15. 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 having a formula selected from the group consisting of;

1) (M1_xM2_1-x)₂LiSiO₄X;

A;

2) (M1_xM2_1-x)₁₀(SiO₄)₃(SO₄)₃X₂;

A;

3) (M1_xM2_1-x)₄(SiO₄)(SO₄)X₂;

A; and

wherein;

M1 and M2 are each independently at least one metal ion selected from the group consisting of Mg²⁺, Ca²⁺, Sr⁺, 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⁺, Pr²⁺, 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, then A is not Eu²⁺;

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

the phosphor modifies a chromaticity of the portion of the light absorbed from the light source; and

the phosphor emits light of a longer wavelength than that of the light absorbed from the light source;

wherein the lighting device produces white light.

17. The lighting device of claim 15, wherein the phosphor further comprises at least one layer of a coating that comprises at least one oxide.