Nitride phosphor and method for preparation thereof, and light emitting device

• US 20040135504A1
• Filed: 11/24/2003
• Published: 07/15/2004
• Est. Priority Date: 03/22/2002
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Kemeshima, Masatoshi, Tamaki, Hiroto, Naitou, Takahiro, Murazaki, Yoshinori, Takashima, Suguru, Sakai, Kazuhiko, Yamada, Motokazu
• Granted Patent: US 7,258,816 B2
• Time in Patent Office: Days
• US Class Current: 313/512
• CPC Class Codes: C01B 21/0602 with two or more other elements chosen from metals, silicon or boron
• CPC Class Codes: C01B 21/0821 Oxynitrides of metals, boron or silicon
• CPC Class Codes: C01P 2002/52 containing elements as dopants
• CPC Class Codes: C01P 2002/84 by UV- or VIS- data
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• 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 2235/3227 Lanthanum oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3286 Gallium oxides, gallates, indium oxides, indates, thallium oxides, thallates or oxide forming salts thereof, e.g. zinc gallate
• CPC Class Codes: C04B 2235/3852 Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
• 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 2235/764 Garnet structure A3B2(CO4)3
• CPC Class Codes: C04B 35/44 based on aluminates
• 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 11/77 containing rare earth metals
• CPC Class Codes: C09K 11/7702 : with zinc or cadmium
• CPC Class Codes: C09K 11/7703 : with alkaline earth metals
• CPC Class Codes: C09K 11/7728 : containing europium
• CPC Class Codes: C09K 11/773 : with zinc or cadmium
• CPC Class Codes: C09K 11/7731 : with alkaline earth metals
• CPC Class Codes: H01L 2224/32245 : the item being metallic
• CPC Class Codes: H01L 2224/45015 : being circular
• CPC Class Codes: H01L 2224/45124 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45139 : Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/45144 : Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 : Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/45169 : Platinum (Pt) as principal constituent
• CPC Class Codes: H01L 2224/48091 : Arched
• CPC Class Codes: H01L 2224/48247 : connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 : connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/48464 : the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• CPC Class Codes: H01L 2224/48465 : the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49107 : on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 : Layer and wire connectors
• CPC Class Codes: H01L 2224/8592 : Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01021 : Scandium [Sc]
• CPC Class Codes: H01L 2924/01037 : Rubidium [Rb]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/01055 : Cesium [Cs]
• CPC Class Codes: H01L 2924/01066 : Dysprosium [Dy]
• CPC Class Codes: H01L 2924/01067 : Holmium [Ho]
• CPC Class Codes: H01L 2924/01068 : Erbium [Er]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/12041 : LED
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2924/20751 : larger or equal to 10 microns less than 20 microns
• CPC Class Codes: H01L 2924/20752 : larger or equal to 20 microns less than 30 microns
• CPC Class Codes: H01L 2924/20753 : larger or equal to 30 microns less than 40 microns
• CPC Class Codes: H01L 2924/20754 : larger or equal to 40 microns less than 50 microns
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H01L 33/502 : Wavelength conversion materials
• CPC Class Codes: Y02B 20/00 : Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

To provide a phosphor containing a comparatively much red component and having high light emitting efficiency, high brightness and further high durability, the nitride phosphor is represented by the general formula L_XM_YN_{((2/3)X+(4/3)Y)}:R or L_XM_YO_ZN_{((2/3)X+(4/3)Y−(2/3)Z)}:R (wherein L is at least one or more selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn, M is at least one or more selected from the Group IV Elements in which Si is essential among C, Si and Ge, and R is at least one or more selected from the rare earth elements in which Eu is essential among Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu.); contains the another elements.

Claims

1. A nitride phosphor having a general formula L_XM_YN_{((2/3)X+(4/3)Y)}:

R or a general formula L_XM_YO_ZN<sub>((2/3)X+(4/3)Y−

(2/3)Z)</sub>;

R in which L is at least one or more elements selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn, M is at least one or more elements selected from the Group IV Elements in which Si is essential among C, Si and Ge, and R is at least one or more elements selected from the rare earth elements in which Eu is essential amongY, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu, said nitride phosphor absorbing at least a portion of light having a first luminescence spectrum in which a peak wave length is 500 nm or less and emitting light having a second luminescence spectrum which has at least one or more of peaks at a range of 520 to 780 nm;

is characterized in further containing at least one or more of different elements selected from the Group I Elements consisting of Li, Na, K, Rb and Cs.

4. The nitride phosphor as in. one of claims 1 to 3;

made by firing under a reducing atmosphere.

9. A light emitting device comprising;

a light emitting element which emits light having a first luminescence spectrum which has a peak wave length of 500 nm or less and,

a phosphor which absorbs at least a portion of light having the first luminescence spectrum and emits light having a second luminescence spectrum which has at least one or more of peaks at a range of 520 to 780 nm,

wherein said phosphor is a phosphor as in one of claims 1 to 4 and 8.

10. The light emitting device according to claim 9;

wherein said device further has one or more phosphors which absorb at least a portion of light having said first luminescence spectrum and at least a portion of light having said second luminescence spectrum and which emit light having the third luminescence spectrum that has at least one or more of peak wave lengths from the blue range to the green range, the yellow range, and the red range.

11. The light emitting device according to claim 10;

wherein said phosphor emitting the light of said third luminescence spectrum is at least any one or more of a yttrium-aluminum oxide phosphor activated by at least cerium, a yttrium-gadolinium-aluminum oxide phosphor activated by at least cerium, and a yttrium-gallium-aluminum oxide phosphor activated by at least cerium.

12. The light emitting device as in one of claims 9 to 11;

wherein said device emits white light by mixing portions of 2 or more kinds of light emitted from said light emitting element, emitted from the phosphor having said second luminescence spectrum, and emitted from the phosphor having said third luminescence spectrum.

2. A nitride phosphor having a general formula L_XM_YN_{((2/3)x+(4/3)Y):}

R or a general formula L_XM_YO_ZN<sub>((2/3)x+(4/3)Y−

(2/3)Z);</sub>

R in which L is at least one or more elements selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn, M is at least one or more elements selected from the Group IV Elements in which Si is essential among C, Si and Ge, and R is at least one or more elements selected from the rare earth elements in which Eu is essential among Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu, said nitride phosphor absorbing at least a portion of light having a first luminescence spectrum in which a peak wave length is 500 nm or less and emitting light having a second luminescence spectrum which has at least one or more peaks at a range of 520 to 780 nm;

is characterized in further containing at least one or more elements selected from the Group V Elements consisting of V, Nb and Ta, the Group VI Elements consisting of Cr, Mo and W, the Group VII Elements consisting of Re and the Group VIII Elements consisting of Fe, Co, Ir, Ni, Pd, Pt and Ru.

3. A nitride phosphor having a general formula L_XM_YN_{((2/3)x+(4/3)Y):}

R or a general formula L_XM_YO_ZN<sub>((2/3)X+(4/3)Y−

(2/3)Z)</sub>;

R in which L is at least one or more selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn, M is at least one or more selected from the Group IV Elements in which Si is essential among C, Si and Ge, and R is at least one or more selected from the rare earth elements in which Eu is essential among Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu, said nitride phosphor absorbing at least a portion of light having a first luminescence spectrum in which a peak wave length is 500 nm or less and emitting light having a second luminescence spectrum which has at least one or more of peaks at a range of 520 to 780 nm;

is characterized in further containing at least one or more elements selected from the Group I Elements consisting of Cu, Ag and Au, the Group III Elements consisting of B, Al, Ga and In, the Group IV Elements consisting of Ti, Zr, Hf, Sn and Pb, the Group V Elements consisting of P, Sb and Bi, and the Group VI Elements consisting of S.

5. A process for production of a nitride phosphor comprising;

a first step of wet mixing process wherein an oxide of R (R is at least one or more elements selected from the rare earth elements in which Eu is essential among Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu.) is mixed with a compound which contains at least one or more elements selected from the Group I Elements consisting of Li, Na, K, Rb, Cs, Cu, Ag and Au, the Group III Elements consisting of B, Al, Ga and In, the Group IV Elements consisting of Ti, Zr, Hf, Sn and Pb, the Group V Elements consisting of V, Nb, Ta, P, Sb and Bi, the Group VI Elements consisting of Cr, Mo, W and S, the Group VII Elements consisting of Re and the Group VIII Elements consisting of Fe, Co, Ir, Ni, Pd, Pt and Ru,

a second step of firing the mixture obtained in the first step,

a third step in which the mixture obtained by the second step is mixed with at least one of the nitride of L (L is at least one or more elements selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn), the nitride of M and the oxide of M (M is at least one or more selected from the Group IV Elements in which Si is essential among C, Si and Ge),and

a fourth step of firing the mixture obtained from the third step in a reducing atmosphere.

6. The process for production of a nitride phosphor according to claim 5;

wherein at least one of said second step and said fourth step carries out firing using a crucible which contains at least one or more elements selected from the Group I Elements consisting of Li, Na, K, Rb, Cs, Cu, Ag and Au, the Group III Elements consisting of B, Al, Ga and In, the Group IV Elements consisting of Ti, Zr, Hf, Sn and Pb, the Group V Elements consisting of V, Nb, Ta, P, Sb and Bi, the Group VI Elements consisting of Cr, Mo, W and S, the Group VII Elements consisting of Re and the Group VIII Elements consisting of Fe, Co, Ir, Ni, Pd, Pt and Ru.

7. The process for production of a nitride phosphor according to claims 5 or 6;

wherein at least one of said second step and said fourth step carries out firing in a furnace made of a material contains at least one or more elements selected from the Group I Elements consisting of Li, Na, K, Rb, Cs, Cu, Ag and Au, the Group III Elements consisting of B, Al, Ga and In, the Group IV Elements consisting of Ti, Zr, Hf, Sn and Pb, the Group V Elements consisting of V, Nb, Ta, P, Sb and Bi, the Group VI Elements consisting of Cr, Mo, W and S, the Group VII Elements consisting of Re and the Group VIII Elements consisting of Fe, Co, Ir, Ni, Pd, Pt and Ru.

8. The nitride phosphor produced by the process as in one of claims 5 to 7;

wherein said phosphor contains at least R (R is at least one or more elements selected from the rare earth elements in which Eu is essential among Y. La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu.), L (L is at least one or more elements selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn), M (M is at least one or more elements selected from the Group IV Elements in which Si is essential among C, Si and Ge), and at least one or more elements selected from the Group I Elements consisting of Li, Na, K, Rb, Cs, Cu, Ag and Au, the Group III Elements consisting of B, Al, Ga and In, the Group IV Elements consisting of Ti, Zr, Hf, Sn and Pb, the Group V Elements consisting of V, Nb, Ta, P, Sb and Bi, the Group VI Elements consisting of Cr, Mo, W and S, the Group VII Elements consisting of Re and the Group VIII Elements consisting of Fe, Co, Ir, Ni, Pd, Pt and Ru.

13. A nitride phosphor which is activated by at least one or more rare earth elements selected from a group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu, and which comprises at least one or more of the Group II Elements selected from a group consisting of Be, Mg, Ca, Sr, Ba and Zn, at least one or more of the Group IV Elements selected from a group consisting of C, Si, Ge, Sn, Ti, Zr and Hf, and N;

is characterized by containing B in the range of 1 ppm to 10000 ppm.

14. The nitride phosphor according to claim 13;

further comprising O.

17. The nitride phosphor as in one of claims 13 to 17;

of which crystal configuration is monoclinic or orthorhombic.

18. The nitride phosphor according to claims 13 or 15;

wherein said rare earth element is one or more of elements in which Eu is essential.

19. The nitride phosphor as in one of claims 13 to 18;

further comprising one or more elements of the Group I Elements selected from a group consisting of Li, Na, K, Rb and Cs in the range of 0.1 ppm to 500 ppm.

20. The nitride phosphor as in one of claims 13 to 19;

further comprising one or more elements selected from the Group I Elements consisting of Cu, Ag and Au, the Group III Elements consisting of Al, Ga and In, the Group IV Elements consisting of Ti, Zr, Hf, Sn and Pb, the Group V Elements consisting of P, Sb and Bi, and the Group VI Element consisting of S in the range of 0.1 ppm to 500 ppm.

21. The nitride phosphor as in one of claims 13 to 20;

further comprising either the elements of Ni or Cr in the range of 1 ppm to 500 ppm.

22. The nitride phosphor as in one of claims 13 to 21;

of which mean particle diameter is in a range of 2 μ

m to 15 μ

m.

23. A light emitting device comprising an excitation light source which emits light of a short wave length range of from near ultra violet to visible light and a phosphor which absorbs at least a portion of light from said excitation light source and emits light having a longer wave length range than light emitted from the excitation light source;

wherein said phosphor comprises a nitride phosphor as in one of claims 13 to 22.

24. The light emitting device according to claim 23;

wherein said phosphor further comprises at least one or more of a phosphor emitting blue light, a phosphor emitting green light and a phosphor emitting yellow light.

25. The light emitting device according to claim 23;

wherein said excitation light source is a semiconductor light emitting element.

26. The light emitting device as in one of claims 23 to 25;

wherein a white light is emitted by mixing a portion of light emitted from said excitation light source which transmits between the particles of said phosphor with a portion of light emitted from said phosphor which is subjected to wavelength conversion by the light emitted from said excitation light source.

15. A nitride phosphor having a general formula L_XM_YN_{((2/3)X+(4/3)Y)}:

R or a general formula L_XM_YO_ZN<sub>((2/3)x+(4/3)Y−

(2/3)Z)</sub>;

R wherein L is at least one or more of the Group II Elements selected from a group consisting of Be, Mg, Ca, Sr, Ba and Zn. M is at least one or more of the Group IV Elements selected from a group consisting of C, Si, Ge, Sn, Ti, Zr, Hf. R is at least one or more of the rare earth elements selected from a group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu. X, Y and Z are 0.5≦

X≦

3, 1.5≦

Y≦

8, and 0<

Z≦

3;

is characterized by containing B in the range of lppm to 10000 ppm.

16. A nitride phosphor which absorbs a portion of light having a first luminescence spectrum and emits light having a second luminescence spectrum at a range different from said first luminescence spectrum;

is characterized in that the luminescence brightness and afterglow are controlled by the amount of B.

27. A nitride phosphor which absorbs at least a portion of light having the first luminescence spectrum and emits light having the second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by being an L-M-N;

Eu, WR-base phosphor (wherein L is at least one or more elements selected from the Group II Elements consisting of Be, Mg, Ca, Sr, Ba and Zn. M is at least one or more elements selected from the GroupIV Elements consisting of C, Si, Ge, Sn, Ti, Zr and Hf. N is nitrogen. Eu is europium. WR is a rare earth element other than Eu.).

31. The nitride phosphor as in one of claims 27 to 30;

wherein said phosphor contains at least one or more elements among Y, La, Ce, Pr, Nd, Gd, Th, Dy, Ho, Er and Lu as above-mentioned WR.

32. The nitride phosphor as in one of claims 27 to 31;

wherein an amount of said WR added is not exceeding 10.0% by weight.

34. The nitride phosphor as in one of claims 27 to 33;

further comprising Mn.

35. The nitride phosphor according to claim 34;

wherein the additional amount of said Mn is in a range of 0.001 to 0.3 mol based on said L.

36. The nitride phosphor according to claim 34;

wherein the additional amount of said Mn is in a range of 0.0025 to 0.03 mol based on said L.

38. The nitride phosphor as in one of claims 27 to 37;

further comprising at least one or more elements selected from the group consisting of Mg, Sr, Ba, Zn, Ca, Ga, In, B, Al, Cu, Li, Na, K, Re, Ni, Cr, Mo, O and Fe.

39. The nitride phosphor as in one of claims 27 to 38;

of which particle size is 3 μ

m or greater.

40. A light emitting device comprising;

a light emitting element which emits light having a first luminescence spectrum and a phosphor which absorbs at least a portion of light of said first luminescence spectrum and emits light having a second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by using the phosphor as in one of claims 27 to 39.

41. The light emitting device according to claim 40;

wherein said phosphor comprises at least one selected from the group comprising a yttrium-aluminum oxide phosphor activated by cerium, a yttrium-gadolinium-aluminum oxide phosphor activated by cerium, and a yttrium-gallium-aluminum oxide phosphor activated by cerium.

28. A nitride phosphor which absorbs at least a portion of light having a first luminescence spectrum and emits light having a second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by being an L-M-O—

N;

Eu, WR (wherein L is at least one or more elements selected from the Group II Elements consisting of Be, Mg, Ca, Sr, Ba and Zn. M is at least one or more elements selected from the Group IV Elements consisting of C, Si, Ge, Sn, Ti, Zr and Hf. O is oxygen. N is nitrogen. Eu is europium. WR is a rare earth element other than Eu.).

33. The nitride phosphor according to claims 28 or 30;

wherein the content of said O is not exceeding 3.0% by weight of the total composition.

29. A nitride phosphor which absorbs at least a portion of light having the first luminescence spectrum and emits light having the second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by being a Ca—

Si—

N;

Eu, WR-base, or Sr—

Si—

N;

Eu, WR-base, or Sr—

Ca—

Si—

N;

Eu, WR-base silicon nitride (wherein WR is a rare earth element other than Eu.).

30. A nitride phosphor which absorbs at least a portion of light having the first luminescence spectrum and emits light having the second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by being a Ca—

Si—

O—

N;

Eu, WR-base, or Sr—

Si—

O—

N;

Eu, WR-base, or Sr—

Ca—

Si—

O—

N;

Eu, WR-base silicon nitride (wherein WR is a rare earth element other than Eu.).

37. The nitride phosphor as in one of claims 34 to 30;

wherein the amount of Mn is 5000 ppm or less.

42. A phosphor which absorbs at least a portion of light having a first luminescence spectrum and emits light having a second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by being a Sr—

Ca—

Si—

N;

R-base silicon nitride having Mn wherein R is one or more rare earth elements in which Eu is essential.

45. The phosphor as in one of claims 42 to 44;

further comprising O.

46. The phosphor according to claim 45;

wherein a content of said O is 3% or less by weight based on the total amount of the compositions.

47. The phosphor as in one of claims 42 to 46;

further comprising at least one or more elements selected from the group consisting of Mg, Sr, Ca, Ba, Zn, B, Al, Cu, Mn, Cr and Ni.

48. The phosphor according to claim 42;

wherein the molar ratio of Sr to Ca is Sr;

Ca=1 to 9;

9 to 1.

49. The phosphor according to claim 42;

wherein the molar ratio of Sr to Ca is Sr;

Ca=1;

1.

50. The phosphor as in one of claims 42 to 49;

wherein a compounding amount of Eu in said phosphor is in a range of 0.003 to 0.5 mol based on Sr—

Ca, Sr and Ca.

51. The phosphor as in one of claims 42 to 49;

wherein the content of Eu in said phosphor is in the range of 0.005 to 0.1 mol based on Sr—

Ca, Sr and Ca.

52. The phosphor as in one of claims 42 to 51;

wherein the content of Mn in said phosphor is in a range of 0.001 to 0.3 mol based on Sr—

Ca, Sr and Ca.

53. The phosphor as in one of claims 42 to 51;

wherein the content of Mn in said phosphor is in a range of 0.0025 to 0.03 mol based on Sr—

Ca, Sr and Ca.

54. The phosphor consists of two or more phosphors selected from the group consisting of the phosphor according to claim 42, the phosphor according to claim 43 and the phosphor according to claim 44.

55. The phosphor as in one of claims 42 to 51;

of which a particle diameter is 3 μ

m or greater.

56. The phosphor as in one of claims 42 to 51;

wherein the content of Mn is 5000 ppm or less.

57. A light emitting device comprising a light emitting device which emits light having a first luminescence spectrum and a phosphor which absorbs at least a portion of light of said first luminescence spectrum and emits light having a second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by using the phosphor as in one of claims 42 to 56.

58. The light emitting device according to claim 57;

wherein said phosphor comprises at least one selected from the group comprising a yttrium-aluminum oxide phosphor activated by cerium, a yttrium-gadolinium-aluminum oxide phosphor activated by cerium, and a yttrium-gallium-aluminum oxide phosphor activated by cerium.

43. A phosphor which absorbs at least a portion of light having a first luminescence spectrum and emits light having a second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by being a Sr—

Si—

N;

R-base silicon nitride having Mn wherein R is one or more rare earth elements in which Eu is essential.

44. A phosphor which absorbs at least a portion of light having a first luminescence spectrum and emits light having a second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by being a Ca—

Si—

N;

R-base silicon nitride having Mn wherein R is one or more rare earth elements in which Eu is essential.

59. A nitride phosphor which contains at least nitrogen, and absorbs at least a portion of light having a first luminescence spectrum and emits light having a second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by having a general formula L_XM_YN_{((2/3)X+(4/3)Y)};

R (wherein L is at least one or more elements selected from the Group II Elements consisting of Be, Mg, Ca, Sr, Ba, Zn, Cd and Hg, M is at least one or more elements selected from the Group IV Elements consisting of C, Si, Ge, Sn, Ti, Zr and Hf, and R is an activator, 0.5≦

X≦

3.1, 1.5≦

Y≦

8.), and containing at least one or more elements selected from a group consisting of Mg, Sr, Ba, Zn, Ca, Ga, In, B, Al, Cu, Mn, Li, Na, K, Re, Ni, Cr, Mo, O and Fe.

60. The nitride phosphor according to claim 59;

is characterized by having a general formula L_XM_YN_{((2/3)X+(4/3)Y)};

R (wherein L is at least one or more elements selected from the Group II Elements consisting of Mg, Ca, Sr and Ba, M is Si, and R is an activator, 0.5≦

X≦

3.1, 1.5≦

Y≦

8.), and containing at least one or more elements selected from a group consisting of Mg, Sr, Ba, Zn, B, Al, Cu, Mn, Cr, O and Ni.

61. The nitride phosphor according to claims 59 or 60;

wherein said R is Eu.

62. The nitride phosphor according to claims 59 or 60;

wherein said R is at least one or more elements among Mn, B, Ce, Mg, Cu, Al and Eu.

63. The nitride phosphor according to claims 59 or 60;

wherein said X and Y are X=2 and Y=5.

64. The nitride phosphor according to claims 59 or 60;

wherein said X and Y are X=1 and Y=7.

65. The nitride phosphor as in one of claims 59 to 62;

wherein said L and said R have a molar ratio of L;

R=1;

0.001 to 1.

66. The nitride phosphor as in one of claims 59 to 65;

of which a mean particle diameter is in a range of 0.1 to 10 μ

m.

67. The nitride phosphor as in one of claims 59 to 66;

wherein said second luminescence spectrum has at least one or more peaks in the yellow to red range.

68. The nitride phosphor as in one of claims 59 to 66;

wherein said second luminescence spectrum has at least one or more peaks within a wave length range of 520 nm to 780 nm.

71. A light emitting device comprising;

a light emitting element which emits light having a first luminescence spectrum and a phosphor which absorbs at least a portion of light of said first luminescence spectrum and emits light having a second luminescence spectrum which is different from said first luminescence spectrum;

is characterized by using the phosphor as in one of claims 59 to 68.

72. The light emitting device according to claim 71;

wherein said phosphor further comprises a yttrium-aluminum oxide phosphor activated by cerium.

73. The light emitting device according to claim 71;

wherein said yttrium-aluminum oxide phosphor activated by cerium and said nitride phosphor is mixed at the ratio of 1 to 15;

1.

74. The light emitting device as in one of claims 71 to 73;

wherein said first luminescence spectrum has a luminescence peak at 360 to 550 nm,

wherein a light in white range is emitted by mixing a portion of light having said first luminescence spectrum and a portion of light having said second luminescence spectrum.

75. The light emitting device as in one of claims 71 to 74;

wherein said phosphor is a powder or a particle, and is contained in a light transmitting material.

76. The light emitting device as in one of claims 71 to 75;

wherein said semiconductor light emitting element is a III Group nitride-base compound semiconductor light emitting element.

77. The light emitting device as in one of claims 71 to 76;

wherein an average color rendering index Ra is in a range of 75 to 95 and a color temperature is in a range of 2000K to 8000K.

69. A process for production of a nitride phosphor which has a general formula L_XM_YN_{((2/3)x+(4/3)Y)}:

R (wherein L is at least one or more elements selected from the Group II Elements consisitng of Be, Mg, Ca, Sr, Ba, Zn, Cd and Hg, M is at least one or more elements selected from the Group IV Elements consisting of C, Si, Ge, Sn, Ti, Zr and Hf, and R is an activator.), and contains at least one or more elements selected from a group consisting of Mg, Sr, Ba, Zn, Ca, Ga, In, B, Al, Cu, Mn, Li, Na, K, Re, Ni, Cr, Mo, O and Fe;

characterized by having a step of firing said raw materials in ammonia atmosphere.

70. The process for production of said nitride phosphor according to claim 69;

wherein said step of firing is carried out using a crucible made of boron nitride.

78. A process for production of a nitride phosphor which contains at least nitrogen, and absorbs at least a portion of light having a first luminescence spectrum and emits light having a second luminescence spectrum which is different from the above-mentioned first luminescence spectrum;

is characterized by having a step of firing in ammonia atmosphere.

79. The process for production of said nitride phosphor according to claim 78;

wherein said second luminescence spectrum has at least one or more peaks in the yellow to red range.

80. The process for production of said nitride phosphor according to claim 78;

wherein said firing is carried out using a crucible made of boron nitride material.

81. The process for production of said nitride phosphor as in one of claims 78 to 80;

wherein said nitride phosphor has a general formula L_XM_YN_{((2/3)X+(4/3)Y)};

R (wherein L is at least one or more elements selected from the Group II Elements consisting of Be, Mg, Ca, Sr, Ba, Zn, Cd and Hg, M is at least one or more elements selected from the Group IV Elements consisting of C, Si, Ge, Sn, Ti, Zr and Hf, and R is an activator.).

82. The process for production of said nitride phosphor as in one of claims 78 to 81;

wherein said nitride phosphor has a general formula L_XM_YN_{((2/3)x+(4/3)Y)};

R (wherein L is at least one or more elements selected from the Group II Elements consisting of Mg, Ca, Sr and Ba, M is Si, and R is an activator.).

83. The process for production of said nitride phosphor as in one of claims 78 to 81;

further comprising a step of mixing a nitride of L, a nitride of M and a compound of R.

84. The process for production of said nitride phosphor as in one of claims 78 to 83;

wherein said activator R is Eu.

85. The process for production of said nitride phosphor as in one of claims 81 to 84;

wherein said L and said R has a relation of the molar ratio of L;

R=1;

0.001 to 1.

86. The nitride phosphor prepared by the process as in one of claims 78 to 85.

87. A light emitting device comprising a light emitting device which has at least a semiconductor light emitting element which emits light of a first luminescence spectrum, and a nitride phosphor which contains at least nitrogen, and absorbs at least a portion of light of said first luminescence spectrum and emits light of a second luminescence spectrum which is different from said first luminescence spectrum;

is characterized in that said nitride phosphor contains the nitride phosphor according to claim 86.

88. A light emitting device comprising a light emitting element, a first phosphor which absorbs at least the portion of light from said light emitting element and emits light having a different wave length, and a second phosphor which absorbs at least the portion of light from said light emitting element and emits light having a different wave length,

wherein the peak wave length of luminescence spectrum which said light emitting element has is situated at a longer wave length side than the peak wave length of excitation spectrum which the first phosphor has and the peak wave length of excitation spectrum which the second phosphor has.

89. The light emitting device according to claim 88;

wherein the peak wave length of luminescence spectrum of the light emitting element is shifted toward shorter wavelength side in accordance with the increase of electric current density.

90. The light emitting device according to claims 88 or 89;

wherein said first phosphor and said second phosphor have a nearly equal change of luminescence intensity in accordance with the change of ambient temperatures of the first phosphor and the second phosphor.

91. The light emitting device according to claim 90;

wherein the change of ambient temperatures of the first phosphor and the second phosphor is caused by the change of the input electric current to said light emitting element.

92. The light emitting device as in one of claims 88 to 91;

wherein the peak wave length of luminescence spectrum of said light emitting element is in a range of 350 nm to 530 nm.

93. The light emitting device as in one of claims 88 to 92;

wherein said first phosphor has a higher excitation efficiency at the short wavelength side of said wave length change than the long wavelength side within a range of the wave length change of the light emitting element which is generated at changing the electric current density of the light emitting element.

94. The light emitting device as in one of claims 88 to 93;

wherein said first phosphor has the peak wave length of excitation spectrum which the first phosphor has at the short wavelength side of said wave length change within a range of the wave length change of the light emitting element which is generated at changing the electric current density of the light emitting element.

95. The light emitting device as in one of claims 88 to 94;

wherein said first phosphor contains a yttrium-aluminum-garnet-base phosphor which contains Y and Al, and contains at least one of elements selected from the group consisting of Lu, Sc, La, Gd, Th, Eu and Sm and at least one of elements selected from the group consisting of Ga and In and is activated by at least one of elements selected from the rare earth elements.

96. The light emitting device as in one of claims 88 to 95;

wherein the difference between the peak wave length of excitation spectrum which said first phosphor has and the peak wave length of excitation spectrum which said light emitting element has is 40 nm or less.

97. The light emitting device as in one of claims 88 to 96;

wherein said second phosphor has a higher excitation efficiency at the short wavelength side of said wave length change than the long wavelength side within a range of the wave length change of the light emitting element which is generated at changing the electric current density of the light emitting element.

98. The light emitting device as in one of claims 88 to 97;

wherein said second phosphor contains a nitride-base phosphor which contains N, and contains at least one of elements selected from the group consisting of Be, Mg, Ca, Sr, Ba and Zn and at least one elements selected from the group consisting of C, Si, Ge, Sn, Ti, Zr and Hf, and is activated by at least one of elements selected from the rare earth elements.

99. The light emitting device as in one of claims 88 to 97;

wherein said light emitting device is the light source of a back light for a liquid crystal display or a light source for illumination.

100. A light emitting device comprising a light sources and a plural number of phosphors which absorb at least the portion of light from said light source and emit light having a different wave length,

wherein said phosphors contain the first phosphor on at least one of the light sources and at least one of the second phosphors in which at least a portion of light emitted is absorbed in the first phosphor, said first phosphor being situated at the light source side than the second phosphors.

101. The light emitting device according to claim 100;

wherein the second phosphors are situated on at least one of the light sources, and/or at least one of light sources different from said at least one of light sources.

102. The light emitting device according to claims 100 to 101;

wherein said light emitting device has the first concave portion mounting said first phosphor and at least one of the light sources and the second concave portion mounting said second phosphor and at least one of the light sources.

103. The light emitting device as in one of claims 100 to 102;

wherein said first phosphor contains a nitride-base phosphor which contains N, and contains at least one of elements selected from the group consisting of Be, Mg, Ca, Sr, Ba and Zn and at least one elements selected from the group consisting of C, Si, Ge, Sn, Ti, Zr and Hf and is activated by at least one of elements selected from the rare earth elements.

104. The light emitting device as in one of claims 100 to 103;

wherein said second phosphor contains a yttrium-aluminum-garnet-base phosphor which contains Y and Al, and contains at least one of elements selected from the group consisting of Lu, Sc, La, Gd, Tb, Eu and Sm and at least one of elements selected from the group consisting of Ga and In and is activated by at least one of elements selected from the rare earth elements.

105. The light emitting device as in one of claims 100 to 104;

wherein said second phosphor has a nearly equal decreasing rate of luminescence output against the raise of temperature as said first phosphor.

106. The light emitting device as in one of claims 100 to 105;

wherein the light sources are semiconductor light emitting elements.

107. The light emitting device as in one of claims 100 to 106;

wherein said light sources are light sources which combined the semiconductor light emitting elements with the phosphors which absorb at least the portion of light from said semiconductor light emitting elements and emit light having a different wave length.

108. The light emitting device as in one of claims 100 to 107;

wherein the light sources have the peak wave length of luminescence spectrum of 350 nm to 530 nm.

109. The light emitting device as in one of claims 100 to 108;

wherein the light emitting device is the light source of a back light for a liquid crystal display or a light source for illumination.

110. The light emitting device as in one of claims 100 to 109;

wherein light sources which emit light exciting the first phosphors and the luminescence outputs of light sources which emit light exciting the second phosphors can be respectively controlled independently.