Phosphor and manufacturing method for the same, and light emitting device using the phosphor

• US 20060244356A1
• Filed: 06/10/2005
• Published: 11/02/2006
• Est. Priority Date: 04/28/2005
• Status: Active Grant

• Current Assignee: Dowa Electronics Materials Co. Ltd. (DOWA Holdings Company Limited)
• Original Assignee: Dowa Mining Company Limited
• Inventors: Nagatomi, Akira, Yamashita, Shuji, Ikuta, Tetsuya
• Granted Patent: US 7,476,336 B2
• Time in Patent Office: Days
• US Class Current: 313/485
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7715 containing cerium
• CPC Class Codes: C09K 11/77218 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/7728 containing europium
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source

Abstract

To provide a phosphor having an emission spectrum with a broad peak in range from green color to red color, and having excellent emission efficiency and luminance. A phosphor is provided, which is given by a general composition formula expressed by MmAaBbOoNn:Z, (where element M is more than one kind of element having bivalent valency, element A is more than one kind of element having tervalent valency, element B is more than one kind of element having tetravalent valency, O is oxygen, N is nitrogen, and element Z is more than one kind of element acting as an activator.), satisfying 2.5<(a+b)/m<4.5, 0<a/m<2.0, 2.0<b/m<4.0, 0<o/m<1.0, o<n, n=2/3 m+a+4/3b−2/3o.

Claims

1. A phosphor, which is given by a general composition formula expressed by MmAaBbOoNn:

Z, (where element M is more than one kind of element having bivalent valency, element A is more than one kind of element having tervalent valency, element B is more than one kind of element having tetravalent valency, O is oxygen, N is nitrogen, and element Z is more than one kind of element acting as the activator, satisfying 2.5<

(a+b)/m<

4.5, 0<

a/m<

2.0, 2.0<

b/m<

4.0, 0<

o/m<

1.0, o<

n, n=2/3m+a+4/3b−

2/3o.

2. The phosphor according to claim 1, which is given by the composition formula expressed by 2.5<

(a+b)/m<

4.0, 0<

a/m<

1.0, 0<

o/m<

0.5.

3. The phosphor according to claim 1, which is given by the composition formula expressed by 2.5<

(a+b)/m<

4.0, 0.1≦

a/m<

1.0, 2.5≦

b/m≦

3.5.

4. The phosphor according to claim 1, wherein the element M is more than one kind of element selected from a group consisting of Mg, Ca, Sr, Ba, Zn, and rare earth elements having bivalent valency, element A is more than one kind of element selected from a group consisting of Al, Ga, In, Tl, Y, Sc, P, As, Sb, and Bi, element B is more than one kind of element selected from a group consisting of Si, Ge, Sn, Ti, Hf, Mo, W, Cr, Pb, Zr, and element Z is more than one kind of element selected from the group consisting of the rare earth elements and transition metal elements.

5. The phosphor according to claim 1, wherein the element M is more than one kind of element selected from a group consisting of Mg, Ca, Sr, Ba, Zn, element A is more than one kind of element selected from a group consisting of Al, Ga, In, element B is Si and/or Ge, and element Z is more than one kind of element selected from a group consisting of Eu, Ce, Pr, Tb, Mn, and Yb.

6. The phosphor according to claim 1, wherein when the general formula is expressed by MmAaBbOoNn:

Zz, the value of z/(m+z), which is a molar ratio of the element M to the element Z, is not less than 0.0001 and not more than 0.5.

7. The phosphor according to claim 1, wherein the element M needs Sr and further is more than one kind of element properly selected from the group consisting of Ca and Ba, the element A is Al, the element B is Si, and the element Z is Eu and/or Ce.

8. The phosphor according to claim 1, wherein the formula is given by (P₂₅−

P₁₀₀)/P₂₅×

100≦

10.0, where the value of a relative intensity of a maximum peak in an emission spectrum is defined as P₂₅ when the phosphor is irradiated with a predetermined monochromatic light in a wavelength range from 300 nm to 550 nm as an excitation light at 25°

C., and the value of the relative intensity of the maximum peak is defined as P₁₀₀ when the phosphor is irradiated with the predetermined monochromatic light as the excitation light at 100°

C.

9. The phosphor according to claim 1, containing:

not less than 33.0 wt % and not more than 40.0 wt % of Sr;

not less than 1.0 wt % and not more than 6.0 wt % of Al;

not less than 25.0 wt % and not more than 31.0 wt % of Si;

not less than 0.5 wt % and not more than 6.0 wt % of O;

not less than 20.0 wt % and not more than 26.0 wt % of N; and

not less than 0.1 wt % and not more than 8.0 wt % of Eu, wherein when the phosphor is irradiated with more than one kind of monochromatic light or continuous light in the wavelength range from 300 nm to 550 nm as the excitation light, the phosphor has the emission spectrum with a maximum peak wavelength in a range from 630 to 660 nm.

10. The phosphor according to claim 1, which has an orthorhombic crystal structure.

11. The phosphor according to claim 1, which has an X-ray powder diffraction pattern by CoKα

ray with two peaks from 42.0°

to 43.1°

of Bragg angle (2θ

) among the diffraction peaks with 30% or more relative intensity with respect to the relative intensity of the maximum peak.

12. The phosphor according to claim 11, containing a primary particle with particle size of 20 μ

m or less and aggregates in which the primary particle agglutinates, wherein an average particle size (D50) of a powdery phosphor containing the primary particle and the aggregates is not less than 1.0 μ

m and not more than 20.0 μ

m.

13. The phosphor according to claim 12, wherein the aggregates of the primary particle contains a columnar particle.

14. A manufacturing method of the phosphor to manufacture the phosphor according to claim 1, wherein by using a crucible composed of nitride as a firing crucible, a raw material is fired at temperature of not less than 1600°

C. and not more than 2000°

C.

15. The manufacturing method of the phosphor according to claim 14, wherein the raw material is fired by setting pressure inside furnace at 0.5 MPa or less.

16. The manufacturing method of the phosphor according to claim 14, wherein the crucible composed of nitride is a BN crucible.

17. The manufacturing method of the phosphor according to claim 14, wherein the raw material is fired, with gas containing 90% or more of nitrogen gas being kept flowing in a furnace at not less than 0.1 ml/min.

18. The manufacturing method of the phosphor according to claim 14, wherein the raw material is fired in a powdery state.

19. The manufacturing method of the phosphor according to claim 14, wherein carbonate of the element M is used as the raw material of the element M.

20. A light emitting device, having the phosphor according to claim 1 and a light emission part for emitting light of a first wavelength, wherein the light with a wavelength different from the first wavelength is emitted from the phosphor with a part of or the whole part of the light of the first wavelength as an excitation light.

21. The light emitting device according to claim 20, wherein the first wavelength is the wavelength in a range from 300 nm to 550 nm.

22. The light emitting device according to claim 20, wherein the light emission part for emitting the light of the first wavelength is an LED.