Granted Patent B2

US 8,906,262 · App. 11/527,835 · Granted Dec 9, 2014

Abstract

Claims (75)

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 x M2 1-x ) 2 LiSiO 4 X:A;

2) (M1 x M2 1-x ) 10 (SiO 4 ) 3 (SO 4 ) 3 X 2 :A; and

3) (M1 x M2 1-x ) 4 (SiO 4 )(SO 4 )X 2 :A;

wherein:

M1 and M2 are each independently at least one metal ion selected from the group consisting of Mg 2+ , Ca 2+ , Sr + , Ba 2+ , Zn 2+ and Cd 2+ ;

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 Eu 2+ , Yb 2+ , Mn 2+ , Bi 3+ , Pb 2+ , Ce 3+ , Nd 3+ , Pr 2+ , Sm 3+ , Eu 3+ , Gd 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+ and Yb 3+ ;

if the phosphor has the formula (M1 x M2 1-x ) 2 LiSiO 4 X:A, and M1 is Sr 2+ , x is 1 and X is fluoride or M2 is Sr 2+ , x is 0 and X is fluoride, then A is not Eu 2+ ; 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 q Ga 1-q N, wherein 0<q<1; and

the n-type clad layer is formed of Al r Ga 1-r N, 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 Ca 2+ , Sr 2+ , Ba 2+ or a combination thereof;

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

A is Eu 2+ , Mn 2+ , Ce 3+ or a combination thereof.

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

M1 is Ca 2+ ;

M2 is Sr 2+ , Ba 2+ or a combination thereof;

X is fluoride, chloride or a combination thereof; and

A is Eu 2+ , Mn 2+ , Ce 3+ or a combination thereof.

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

CaSiO 3 .(SiO 2 ) n :R∈,Y  (I)

wherein:

R∈ is at least one activator ion selected from the group consisting of Eu 2+ and Mn 2+ ; 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):

CaSiO 3 .(SiO 2 ) n :Eu 2+ ,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):

CaSiO 3 .(SiO 2 ) n :Eu 2+ ,Mn 2+ ,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):

CaSiO 3 .(SiO 2 ) n :Eu 2+ ,I −   (II)

the second phosphor comprises formula (III):

CaSiO 3 .(SiO 2 ) n :Eu 2+ ,Mn 2+ ,I −   (III).

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

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 x M2 1-x ) 2 LiSiO 4 X:A;

2) (M1 x M2 1-x ) 10 (SiO 4 ) 3 (SO 4 ) 3 X 2 :A;

3) (M1 x M2 1-x ) 4 (SiO 4 )(SO 4 )X 2 :A; and

wherein:

M1 and M2 are each independently at least one metal ion selected from the group consisting of Mg 2+ , Ca 2+ , Sr + , Ba 2+ , Zn 2+ and Cd 2+ ;

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 Eu 2+ , Yb 2+ , Mn 2+ , Bi 3+ , Pb 2+ , Ce 3+ , Nd 3+ , Pr 2+ , Sm 3+ , Eu 3+ , Gd 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+ and Yb 3+ ;

if the phosphor has the formula (M1 x M2 1-x ) 2 LiSiO 4 X:A, and M1 is Sr 2+ , x is 1 and X is fluoride, then A is not Eu 2+ ;

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.

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.

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.

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.

Assignments (7)