Phosphor and manufacturing method therefore, and light source using the phosphor

• US 7,476,335 B2
• Filed: 02/23/2005
• Issued: 01/13/2009
• Est. Priority Date: 08/20/2004
• Status: Expired

• Current Assignee: Citizen Electronics Company Limited, Nichia Corporation
• Original Assignee: Dowa Electronics Materials Co. Ltd. (DOWA Holdings Company Limited), Nichia Corporation
• Inventors: Nagatomi, Akira, Sakane, Kenji
• Primary Examiner(s): KOSLOW, CAROL M
• Application Number:
  US11/063,847
• Publication Number:
  US 20060043337A1
• Time in Patent Office: 1,420 Days
• Field of Search: 252/301.4 F, 257/98, 313/503
• US Class Current: 252/301.40F
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3852 Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/3873 Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
• CPC Class Codes: C04B 2235/3895 Non-oxides with a defined oxygen content, e.g. SiOC, TiON
• CPC Class Codes: C04B 2235/5409 expressed by specific surface values
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 35/584 based on silicon nitride
• 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 11/7709 Phosphates
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides

Abstract

To provide a phosphor having a broad emission spectrum with a peak in the range from yellow color to red color (wavelength from 570 nm to 620 nm), having a flat excitation band with large area on the long wavelength side from near ultraviolet/ultraviolet to green color (wavelength from 250 nm to 550 nm), and excellent in emission intensity and luminance, and a method of manufacturing the same, and also a light source such as white LED using the phosphor. As raw materials, Ca₃N₂(2N), AlN(3N), Si₃N₄(3N), and Eu₂O₃(3N) are prepared, and out of each raw material, 0.950/3 mol of Ca₃N₂, 2 mol of AlN, 4/3 mol of Si₃N₄, and 0.050/2 mol of Eu₂O₃ are weighed, and the raw materials thus weighed are mixed by using a mortar. The raw materials thus mixed are put in a BN crucible, and retained/fired for 3 hours at 1700° C. in a nitrogen atmosphere, and thereafter cooled from 1700° C. to 200° C., to thereby obtain the phosphor expressed by a composition formula
Ca_0.950Al₂Si₄O_0.075N_7.917:Eu_0.050.

Claims

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

Z, (where element M is the element having bivalent valency, element A is the element having tervalent valency, element B is the element having tetravalent valency, O is oxygen, N is nitrogen, and element Z is the element acting as the activator), expressed by m=1, a+b<

8, 0<

o≦

1.0, n=2/3m+a+4/3b−

2/3o.

4. The phosphor according to claim 1, which is given as the composition formula expressed by a=2, 4.0≦

b/m≦

5.5.

5. The phosphor according to claim 4, which is given as the composition formula expressed by b/m=4.0.

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

7. The phosphor according to claim 1, wherein the element A is Al and the element B is Si.

8. The phosphor according to claim 1, wherein the element M is one or more kind of element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn.

9. The phosphor according to claim 1, wherein the element Z is one or more kind of element selected from the group consisting of Eu, Mn, Ce, and Tb.

10. The phosphor according to claim 1, wherein the element Z is Eu.

11. The phosphor according to claim 1, wherein the element M is Ca, the element A is Al, and the element B is Si.

12. 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.

14. The phosphor according to claim 1, wherein the phosphor is formed in hexagonal crystals.

15. The phosphor according to claim 1, wherein the phosphor is a powdery form.

16. The phosphor according to claim 15, wherein as average size of the phosphor is not less than 20 μ

m, and not more than 1.0 μ

m.

17. A method of manufacturing a phosphor according to claim 1, wherein by using nitride of each element as a supply source of the element M, the element A, and the element B, the raw material is fired at 1000°

C. or more in an atmosphere of inactive gas.

18. A light source, comprising the phosphor according to claim 1 and a light emitting part for emitting light of a first wavelength, wherein by using a part or the whole part of the light of the first wavelength as an excitation light, the phosphor is caused to emit light with a wavelength different from the first wavelength.

19. The light source according to claim 18, wherein the first wavelength is the wavelength form 250 nm to 550 nm.

20. The light source according to claim 18, wherein the light emitting part for emitting the light of the first wavelength is an LED.

2. A phosphor which is given as a general composition formula expressed by MmAaBbOoNn:

Z, (where element M is the element having bivalent valency, element A is the element having tervalent valency, element B is the element having tetravalent valency, O is oxygen, N is nitrogen, and element Z is the element acting as the activator), expressed by m=1, 1.8≦

a/m≦

5.0, a+b<

8, o≦

1.0, n=2/3m+a+4/3b−

2/3o.

13. The phosphor according to claim 2, containing 8.4 to 13.5 wt % of Ca, 11.7 to 17.9 wt % of Al, 29.8 to 41.7 wt % of Si, 0 to 5.0 wt % of O, 30.5 to 37.0 wt % of N, and 0.01 to 5.0 wt % of Eu, wherein a peak wavelength in an emission spectrum is in a wavelength range from 570 to 620 nm, with chromaticity x of the emission in the range from 0.5 to 0.6, and y in the range from 0.4 to 0.5.

3. A phosphor which is given as a general composition formula expressed by MmAaBbOoNn:

Z (where element M is the element having bivalent valency, element A is the element having tervalent valency, element B is the element having tetravalent valency, O is oxygen, N is nitrogen, and element Z is the element acting as the activator), expressed by m=1, 1.8≦

a/m≦

5.0, 3.0≦

b/m≦

6.2, a+b<

8, o≦

1.0, n=2/3m+a+4/3b−

2/3o.