Metal silicate-silica-based polymorphous phosphors and lighting devices

• US 20060214175A1
• Filed: 06/10/2005
• Published: 09/28/2006
• Est. Priority Date: 03/25/2005
• Status: Active Grant

• Current Assignee: Lightscape Materials, Inc.
• Original Assignee: Sarnoff Corporation (SRI International, Inc.)
• Inventors: Tian, Yongchi
• Granted Patent: US 7,276,183 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C09K 11/7731 with alkaline earth metals
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: H01L 2224/48091 Arched
• 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

Provided, among other things, is a phosphor according to the formula:
[(BvSiO₃)_x(Mv₂SiO₃)_y(Tv₂(SiO₃)₃)_z]_m.(SiO₂)_n:Rε, X  (I)

• wherein x, y and z are any value such that x+y+z=1; By is one or more divalent alkaline earth metals; Mv is one or more monovalent alkaline metals; Tv is one or more trivalent metal ions; Rε is one or more activators selected from Eu²⁺ and Mn²⁺; X is one or more halides; m is 1 or 0; and (i) n>3 if m=1 and provides an amount of silica effective to host useful luminescence or (ii) n=1 if m=0.

Claims

1. A light emitting device comprising:

a semiconductor light source producing light output including wavelengths of 300 nm or more; and

a wavelength manager located between the light source and the light output for the device, comprising a phosphor according to the formula;

[(BvSiO₃)_x(Mv₂SiO₃)_y(Tv₂(SiO₃)₃)_z]_m.(SiO₂)_n;

Rε

, X 

 

(I)

wherein x, y and z are any value such that x+y+z=1;

By is one or more divalent alkaline earth metals;

Mv is one or more monovalent alkaline metals;

Tv is one or more trivalent metal ions;

Rε

is one or more activators selected from Eu²⁺ and Mn²⁺;

X is one or more halides;

m is 1 or 0; and

(i) n>

3 if m=1 and provides an amount of silica effective to host useful luminescence or (ii) n=1 if m=0.

10. The light emitting device of claim 1, wherein the wavelength manager comprises one or more additional phosphors, the one or more additional phosphors adjusting light produced by the device.

11. The light emitting device of claim 10, wherein the wavelength manager changes the light output to white light.

12. A light emitting device according to claim 1, wherein:

the semiconductor light source comprises a double hetero structure comprising a light emitting layer sandwiched between a p-type clad layer and an n-type clad layer.

13. A light emitting device according to claim 12, wherein:

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

q<

1, and the n-type clad layer is formed of Al_rGa_1-rN where 0≦

r<

1; and

/or

the band gap of the p-type clad layer is larger than that of the n-type clad layer.

14. A light emitting device according to claim 1, wherein:

the semiconductor light source comprises a light emitting layer containing indium and comprising a quantum well structure.

15. A light emitting device according to claim 14, wherein:

the quantum well structure comprises a well layer of InGaN and a barrier layer of GaN; and

/or

the quantum well structure comprises a well layer of InGaN and a barrier layer of AlGaN; and

/or

the quantum well structure comprises a well layer of AlInGaN and a barrier layer of AlInGaN, and the band gap energy of the barrier layer is larger than that of the well layer; and

/or

wherein;

the well layer has a thickness of not more than 100 angstroms.

16. A light emitting device according to claim 1, wherein the semiconductor light source comprises a single well light emitting element.

17. A light emitting device according to claim 1, wherein the semiconductor light source comprises multiple light emitting elements on a substrate.

27. A method of making a light emitting device according to claim 1, comprising associating the phosphor with the semiconductor light source so that the light emission of the device is modified by the associated phosphor.

2-9. -9. (canceled)

18-26. -26. (canceled)

28. A phosphor according to the formula:

[(BvSiO₃)_x(Mv₂SiO₃)_y(Tv₂(SiO₃)₃)_z]_m.(SiO₂)_n;

Rε

, X 

 

(I)

wherein x, y and z are any value such that x+y+z=1;

By is one or more divalent alkaline earth metals;

Mv is one or more monovalent alkaline metals;

Tv is one or more trivalent metal ions;

Rε

is one or more activators selected from Eu²⁺ and Mn²⁺;

X is one or more halides;

m is 1 or 0; and

(i) n>

3 if m=1 and provides an amount of silica effective to host useful luminescence or (ii) n=1 if m=0.

29. The phosphor of claim 28, wherein Mv comprises one or more ions of Li, Na or K.

30. The phosphor of claim 28, wherein Bv comprises one or more divalent alkaline earth metals.

31. The phosphor of claim 30, wherein By comprises one or more divalent ions of Ca or Sr.

32. The phosphor of claim 28, wherein Bv comprises one or more divalent ions of Be, Mg, Ca, Sr, Ba, Mn, Co, Ni, Cu, Zn, Cd or Hg.

33. The phosphor of claim 28, wherein Tv comprises one or more trivalent ions of Al, Ga, In, Sc, Y or La.

34. The phosphor of claim 28, wherein Rε

comprises substantially all Eu²⁺.

35. The phosphor of claim 28, wherein Rε

comprises substantially all Mn²⁺.

36. The phosphor of claim 28, wherein Rε

comprises substantially all Eu²⁺ and Mn²⁺.

37. The phosphor of claim 28, wherein the phosphor is according to (CaSiO₃).(SiO₂):

Eu²⁺, Mn²⁺, I⁻

, with the concentration and ratio of Eu²⁺ and Mn²⁺ selected provide a peak emission between 620 nm and 660 nm, and a chromaticity of x=0.62±

0.06, y=0.30±

0.06.

38. The phosphor of claim 28, wherein the phosphor is according to (CaSiO₃).(SiO₂):

Eu²⁺, I⁻

, with the concentration of Eu²⁺ selected to provide a peak emission between 445 nm and 480 nm, and a chromaticity of x=0.20±

0.06, y=0.10±

0.06.

39. The phosphor of claim 28, wherein the phosphor is according to (CaSiO₃).(SiO₂):

Eu²⁺, Mn²⁺, Cl⁻

, with the concentration and ratio of Eu²⁺ and Mn²⁺ selected to provide a chromaticity of x=0.40±

0.06, y=0.20±

0.06.

40. A phosphor of claim 28, wherein the phosphor comprises metal silicate in wollastonite form and silica in cristobalite form.

41. A phosphor of claim 28, wherein the phosphor comprises metal silicate in calcite form and silica in cristobalite form.

42. A phosphor of claim 28, wherein the phosphor comprises metal silicate in enstalite form and silica in cristobalite form.

43. A phosphor of claim 28, wherein the mole percentage of X is 5% or less of SiO₂

44. A method of making a phosphor according to the formula:

[(BvSiO₃)_x(Mv₂SiO₃)_y(Tv₂(SiO₃)₃)_z]_m.(SiO₂)_n;

Rε

, X 

 

(I)

wherein x, y and z are any value such that x+y+z=1;

By is one or more divalent alkaline earth metals;

Mv is one or more monovalent alkaline metals;

Tv is one or more trivalent metal ions;

Rε

is one or more activators selected from Eu²⁺ and Mn²⁺;

X is one or more halides;

m is 1 or 0; and

(i) n>

3 if m=1 and provides an amount of silica effective to host useful luminescence or (ii) n=1 if m=0,

comprising;

providing an appropriate mixture of precursors optionally including a halide source; and

firing the product of the first heating at a temperature from 900°

C. to 1300°

C. under a reducing atmosphere and in the presence of a halide source,

wherein one or more of the following applies;

the process further comprises, prior to the firing, heating the appropriate mixture, optionally including a halide source, at a temperature from 700°

C. to 1100°

C. under a reducing atmosphere, where the heating is at a temperature lower than that of the firing, or

the mole percentage of X in the phosphor product is 5% or less of SiO₂.

45. The method of claim 44, further comprising,

prior to the firing, heating the appropriate mixture, optionally including a halide source, at a temperature from 700°

C. to 1100°

C. under a reducing atmosphere, where the heating is at a temperature lower than that of the firing.

46. The method of claim 45, wherein a halide source is present in the heating.