Oxynitride phosphor activated by a rare earth element, and sialon type phosphor

• US 20030030038A1
• Filed: 06/06/2002
• Published: 02/13/2003
• Est. Priority Date: 06/07/2001
• Status: Active Grant

• Current Assignee: National Institute for Materials Science
• Original Assignee: National Institute for Materials Science
• Inventors: Endo, Tadashi, Komatsu, Masakazu, Ueda, Kyouta, Mitomo, Mamoru
• Granted Patent: US 6,632,379 B2
• Time in Patent Office: Days
• US Class Current: 252/500
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/3869 Aluminium oxynitrides, e.g. AlON, sialon
• CPC Class Codes: C04B 2235/3878 Alpha silicon nitrides
• CPC Class Codes: C04B 2235/766 Trigonal symmetry, e.g. alpha-Si3N4 or alpha-Sialon
• CPC Class Codes: C04B 35/597 based on silicon oxynitride, e.g. SIALONS
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/77068 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/77498 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/77928 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides

Abstract

An oxynitride phosphor activated by a rare earth element, represented by the formula Me_xSi_12−(m+n)Al_(m+n)O_nN_16−n:Re1_yRe2_x, wherein a part or all of metal Me (where Me is at least one metal selected from the group consisting of Ca, Mg, Y and lanthanide metals excluding La and Ce) in α-sialon solid solution, is substituted by lanthanide metal Re1 (where Re1 is at least one metal selected from the group consisting of Ce, Pr, Eu, Tb, Yb and Er), or two lanthanide metals Re1 and a coactivator Re2 (where Re2 is Dy), to be an emission center.

A sialon type phosphor in the form of a powder comprising at least 40 wt % of α-sialon represented by the formula (Ca_x,M_y) (Si, Al)₁₂(O, N)₁₆ (where M is at least one metal selected from the group consisting of Eu, Tb, Yb and Er, 0.05<(x+y)<0.3, 0.02<x<0.27 and 0.03<y<0.3) and having a structure such that Ca sites of Ca-α-sialon are partially substituted by other metal M, at most 40 wt % of β-sialon, and at most 30 wt % of unreacted silicon nitride.

Claims

1. An oxynitride phosphor activated by a rare earth element, represented by the formula Me_xSi₁₂₋

(m+n)Al(m+n)O_nN<sub>16−

n</sub>;

Re1_yRe2_x, wherein a part or all of metal Me (where Me is at least one metal selected from the group consisting of Ca, Mg, Y and lanthanide metals excluding La and Ce) in α

-sialon solid solution, is substituted by lanthanide metal Re1 (where Re1 is at least one metal selected from the group consisting of Ce, Pr, Eu, Tb, Yb and Er), or two lanthanide metals Re1 and a coactivator Re2 (where Re2 is Dy), to be an emission center.

2. The oxynitride phosphor activated by a rare earth element according to claim 1, wherein when metal Me is bivalent, 0.6<

m<

3.0 and 0≦

n<

1.5.

3. The oxynitride phosphor activated by a rare earth element according to claim 1, wherein when metal Me is trivalent, 0.9<

m<

4.5 and 0≦

n<

1.5.

4. The oxynitride phosphor activated by a rare earth element according to claim 1, wherein m=1.5, n=0.75 and in the composition formula Me_xSi_9.75Al_2.25O_0.75N_15.25:

Re1_yRe2_z, 0.3<

x+y<

0.75 and 0.01<

y+z<

0.7 (where y>

0.01 and 0.0≦

z<

0.1).

5. The oxynitride phosphor activated by a rare earth element according to claim 4, wherein 0.3<

x+y+z<

1.5, 0.01<

y<

0.7 and 0≦

z<

0.1.

6. The oxynitride phosphor activated by a rare earth element according to claim 2, wherein metal Me is Ca.

7. A sialon type phosphor in the form of a powder comprising at least 40 wt % of α

-sialon represented by the formula (Ca_x, M_y) (Si, Al)₁₂ (O, N)₁₆ (where M is at least one metal selected from the group consisting of Eu, Tb, Yb and Er, 0.05<

(x+y)<

0.3, 0.02<

x<

0.27 and 0.03<

y<

0.3) and having a structure such that Ca sites of Ca-α

-sialon are partially substituted by other metal M, at most 40 wt % of β

-sialon, and at most 30 wt % of unreacted silicon nitride.

8. The sialon type phosphor according to claim 7, wherein the chemical composition of the powder as a whole, is within a range defined by three compositional lines of Si₃N₄−

a(M₂O₃˜

9AlN), Si₃N₄−

b(CaO·

3AlN) and Si₃N₄−

c(AlN·

Al₂O₃), where 4×

10<sup>−

3</sup><

a<

4×

10<sup>−

2</sup>, 8×

10<sup>−

3</sup><

b<

8×

10<sup>−

2</sup> and 10<sup>−

2</sup><

c<

10<sup>−

1</sup>.