Phosphor and light-emitting equipment using phosphor

1. A phosphor comprising an inorganic compound represented by the composition formula:

M a A b D c E d X e

wherein:

M is one or two or more elements selected from the group consisting of Mn, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb;

A is one or two or more elements selected from the group consisting of divalent metal elements other than M Element;

D is one or two or more elements selected from the group consisting of tetravalent metal elements;

E is one or two or more elements selected from the group consisting of trivalent metal elements;

X is one or two or more elements selected from the group consisting of O, N, and F;

a+b= 1;

0.00001 ≦a≦ 0.1;

0.5≦ c≦ 1.8;

0.5 ≦d≦ 1.8;

0.8×(2/3+4/3 ×c+d )≦ e;

e≦ 1.2×(2/3+4/3 ×c+d ).

2. The phosphor of claim 1 , wherein the inorganic compound has the same crystal structure as CaAlSiN 3 or a crystal structure such that:

positions of skeletal atoms in the inorganic compound are not sufficiently different from skeletal atoms in CaAlSiN 3 that corresponding chemical bonds are cleaved; and

lengths of chemical bonds in the inorganic compound corresponding to Al—N and Si—N bonds in CaAlSiN 3 differ from lengths of Al—N and Si—N bonds in CaAlSiN 3 by +15%.

3. The phosphor of claim 1 , wherein the inorganic compound comprises CaAlSiN 3 :Eu.

4. The phosphor according to claim 1 , wherein:

A is one or two or more elements selected from the group consisting of Mg, Ca, Sr, and Ba;

D is one or two or more elements selected from the group consisting of Si, Ge, Sn, Ti, Zr, and Hf; and

E is one or two or more elements selected from the group consisting of B, Al, Ga, In, Sc, Y, La, Gd, and Lu.

5. The phosphor according to claim 1 , wherein:

M comprises Eu;

A comprises Ca;

D comprises Si;

E comprises Al; and

X comprises N.

6. The phosphor according to claim 1 , wherein the inorganic compound is a CaAlSiN 3 crystal phase or a solid solution of a CaAlSiN 3 crystal phase.

7. The phosphor according to claim 1 , wherein:

M comprises Eu;

A comprises Ca;

D comprises Si;

E comprises Al; and

X comprises a mixture of N and O.

8. The phosphor according to claim 1 , wherein A comprises Sr.

9. The phosphor according to claim 8 , wherein numbers of atoms of Ca and Sr in the inorganic compound satisfy:

0.02≦(number of atoms of Ca)/{(number of atoms of Ca)+(number of atoms of Sr)}<1.

10. The phosphor according to claim 1 , wherein X comprises N and O.

11. The phosphor according to claim 10 , wherein numbers of atoms of O and N in the inorganic compound satisfy:

0.5≦(number of atoms of N)/{(number of atoms of N)+(number of atoms of 0)}≦1.

12. The phosphor according to claim 10 , wherein the inorganic compound is represented by:

M a A b D 1−x E 1+x N 3−x O x

wherein:

a+b=1; and

0<x≦0.5.

13. The phosphor according to claim 1 , wherein:

the inorganic compound is in the form of a powder;

the powder has an average particle size of 0.1 μm to 20 μm; and

the powder comprises single crystal particles or aggregates of single crystals.

14. The phosphor according to claim 1 , wherein the inorganic compound comprises impurity elements of Fe, Co, and Ni in an amount of 50 ppm or less.

15. The phosphor according to claim 1 , comprising the inorganic compound and a further crystal phase or amorphous phase;

wherein the inorganic compound is present in an amount of at least 20% by weight based on a total weight of the inorganic compound and the further crystal phase or amorphous phase.

16. The phosphor according to claim 15 , wherein the further crystal phase or amorphous phase comprises an inorganic substance having electroconductivity.

17. The phosphor according to claim 16 , wherein the inorganic substance having electroconductivity is a material comprising an oxide, oxynitride, or nitride comprising one or two or more elements selected from the group consisting of Zn, Al, Ga, In, and Sn.

18. The phosphor according to claim 15 , wherein the further crystal phase or amorphous phase differs in composition from the inorganic compound.

19. The phosphor according to claim 1 , wherein the phosphor emits a fluorescent light having a peak wavelength of from 570 nm to 700 nm, when irradiated with an excitation source.

20. The phosphor according to claim 19 , wherein the excitation source is an ultraviolet ray or visible light having a wavelength of 100 nm to 600 nm.

21. The phosphor according to claim 19 , wherein:

the inorganic compound is a CaAlSiN 3 crystal phase;

Eu is dissolved in the crystal phase; and

the phosphor emits a fluorescent light having a peak wavelength of from 600 nm to 700 nm, when irradiated with light having a wavelength of from 100 nm to 600 nm.

22. The phosphor according to claim 19 , wherein the excitation source is an electron beam or an X-ray.

23. The phosphor according to claim 19 , wherein the phosphor emits fluorescent light having a color satisfying:

0.45 ≦x≦ 0.7

as a value of (x, y) on the CIE coordinates.