Nitride phosphor and production process thereof, and light emitting device

• US 8,076,847 B2
• Filed: 05/15/2009
• Issued: 12/13/2011
• Est. Priority Date: 03/22/2002
• Status: Expired due to Fees

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Tamaki, Hiroto, Naitou, Takahiro, Murazaki, Yoshinori
• Primary Examiner(s): Williams, Joseph L
• Application Number:
  US12/453,587
• Publication Number:
  US 20090284132A1
• Time in Patent Office: 942 Days
• Field of Search: 313498-512, 257 98-100
• 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 light emitting device comprising:

a package having a first concave portion and a second concave portion, the first concave portion being bored on a bottom of the second concave portion in an inner direction opposite to a direction toward the face of observing luminescence to form a step on the bottom of the second concave portion;

light sources comprising a first light source mounted in the first concave portion and a second light source mounted in the second concave portion;

a first phosphor layer disposed in the first concave portion the first phosphor layer absorbing at least a portion of a light emitted from the first light source and emitting a first light having a wavelength longer than the light emitted from the first light source;

a second phosphor layer which absorbs at least a portion of a light emitted from the first light source and the light emitted from the second light source and which emits a second light having a wavelength longer than the light emitted from the second light source;

wherein a peak wavelength of the first light is longer than a peak wavelength of the second light, and wherein

the first light emitted from the first phosphor is diffused by the second phosphor without being absorbed.

2. The light emitting device according to claim 1,

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 element 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.

3. The light emitting device according to claim 1,

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.

4. The light emitting device according to claim 1,

wherein the light sources are semiconductor light emitting elements.

5. The light-emitting device according to claim 1,

wherein at least one of the light sources is a light source that a semiconductor light emitting element which emits an ultra violet light and a phosphor which absorb the ultra violet light and emit a light having a different wavelength are combined.

6. The light emitting device according to claim 1,

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 element 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,

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, and

wherein a deference between a decreasing rate of the luminescence output of the nitride-base phosphor and the YAG-base phosphor is 2.0×

10<sup>−

3</sup> [a. u./°

C.] or less.

7. The light emitting device according to claim 1,

wherein the first light source is covered with the first phosphor layer and the first phosphor is covered with the second phosphor.

8. A light emitting device comprising:

a package having a first concave portion and a second concave portion, the first concave portion being bored on a bottom of the second concave portion in an inner direction opposite to a direction toward the face of observing luminescence to form a step on the bottom of the second concave portion,

light sources comprising a first light source mounted in the first concave portion and a second light source mounted in the second concave portion, the light sources being capable of emitting a blue light;

a first phosphor layer disposed in the first concave portion, the first phosphor layer absorbing at least a portion of a light emitted from the first light source and emitting a first light having a peak wavelength in a red region;

a second phosphor layer which absorbs at least a portion of a light emitted from the first light source and the light emitted from the second light source and which emits a second light having a peak wavelength in a yellow region, and wherein the first light emitted from the first phosphor is diffused without being absorbed by the second phosphor.

9. The light emitting device according to claim 8,

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 element 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.

10. The light emitting device according to claim 8,

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 element selected from the group consisting of Ga and In and is activated by at least one of elements selected from the rare earth elements.

11. The light emitting device according to claim 8,

wherein the light sources are semiconductor light emitting elements.

12. The light emitting device according to claim 8,

wherein at least one of the light sources is a light source that a semiconductor light emitting element which emits an ultra violet light and a phosphor which absorbs the ultra violet light and emits a light having a different wavelength are combined.

13. The light emitting device according to claim 8,

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 element 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,

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, and

wherein a deference between a decreasing rate of the luminescence output of the nitride-base phosphor and the YAG-base phosphor is 2.0×

10<sup>−

3</sup> [a. u./°

C.] or less.

14. The light emitting device according to claim 8,

wherein the first light source is covered with the first phosphor layer and the first phosphor is covered with the second phosphor.

15. A light emitting device comprising:

a light source having a peak wavelength in a range of 350 nm to 530 nm;

a phosphor layer having two layers of a first phosphor layer which absorbs at least a portion of a light emitted from the light source and emits a light having a wavelength different from the light emitted from the light source,

wherein the first phosphor layer absorbs at least a portion of a light emitted from the light source and emits a first light having a peak wavelength in a range of 600 nm to 700 nm,

wherein the second phosphor layer absorbs at least a portion of the light emitted from the light source and emits a second light having a wavelength longer than the light emitted from the light source,

wherein a peak wavelength of the first light is longer than a peak wavelength of the second light,

wherein the first phosphor layer is positioned nearer to the light source than the second phosphor,

wherein the first phosphor layer includes a first phosphor,

the second phosphor layer includes a second phosphor in which at least part of a light emitted from the second phosphor is absorbed in the first phosphor,

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.

16. A light emitting device according to claim 15,

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 element 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.

17. A light emitting device according to claim 15,

wherein the light source is semiconductor light emitting element.

18. The light emitting device according to claim 15,

wherein at least one of the light sources is a light source that a semiconductor light emitting element which emits an ultra violet light and a phosphor which absorbs the ultra violet light and emit a light having a different wavelength are combined.

19. The light emitting device according to claim 15,

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 element 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,

wherein a deference between a decreasing rate of the luminescence output of the nitride-base phosphor and the YAG-base phosphor is 2.0×

10<sup>−

3</sup> [a. u./°

C.] or less.

20. The light emitting device according to claim 15,

wherein the light source is covered with the first phosphor layer and the first phosphor is covered with the second phosphor.

21. A light emitting device comprising:

a light source being capable of emitting a blue light;

a phosphor layer having two layers of a first phosphor layer which absorbs at least a portion of a light emitted from the light source and emits a light having a wavelength different from the light emitted from the light source,

wherein the first phosphor layer emits a light having a peak wavelength in a red range,

wherein the second phosphor layer emits a light having a wavelength longer in a yellow to green range,

wherein the first phosphor layer is positioned nearer to the light source than the second phosphor,

wherein the first phosphor layer includes a first phosphor being capable of emitting a red light,

the second phosphor layer includes a second phosphor in which at least part of a light emitted from the second phosphor is absorbed in the first phosphor,

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.

22. A light emitting device according to claim 21,

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 element 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.

23. A light emitting device according to claim 21,

wherein the light source is semiconductor light emitting element.

24. The light emitting device according to claim 21,

wherein at least one of the light sources is a light source that a semiconductor light emitting element which emits an ultra violet light and a phosphor which absorb the ultra violet light and emit a light having a different wavelength are combined.

25. A light emitting device according to claim 21,

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 element 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,

wherein a deference between a decreasing rate of the luminescence output of the nitride-base phosphor and the YAG-base phosphor is 2.0×

10<sup>−

3</sup> [a. u./°

C.] or less.

26. The light emitting device according to claim 21,

wherein the light source is covered with the first phosphor layer and the first phosphor is covered with the second phosphor.