Light emitting device
A light emitting device according to one embodiment includes a light emitting element that emits light having a wavelength of 380 nm to 470 nm; a CASN first red phosphor that is disposed on the light emitting element; a sialon second red phosphor that is disposed on the light emitting element; and a sialon green phosphor that is disposed on the light emitting element.
1. A light emitting device comprising:
a light emitting element emitting light having a wavelength of 380 nm to 470 nm;
a first red phosphor disposed on the light emitting element, the first red phosphor having a composition expressed by equation (1);
a second red phosphor disposed on the light emitting element, the second red phosphor having a composition expressed by equation (2); and
a green phosphor disposed on the light emitting element, the green phosphor having a composition expressed by equation (3),
(Ca 1-x1 Eu x1 ) a1 AlSi b1 O c1 N d1 :Eu (1)
(In the equation (1), x1, a1, b1, c1 and d1 satisfy the following relationship: 0<x1<0.03, 0.90<a1<1.1, 0.90<b1<1.1, 0.20<c1<0.45, 2.40<d1≦3.00)
(Sr 1-x2 Eu x2 ) a2 Si b2 AlO c2 N d2 (2)
(In the equation (2), x2, a2, b2, c2, and d2 satisfy the following relationship: 0<x2<1, 0.55<a2<0.95, 2.0<b2<3.9, 0<c2<0.6, 4<d2<5.7)
(Sr 1-x Eu x ) 3-y Si 13-z Al 3+z O 2+u N 21-w (3)
(In the equation (3), x, y, z, u, and w satisfy the following relationship: 0<x<1, −0.1<y<0.3, −3<z≦1, −3<u−w≦1.5, where −2≦u and w≦21 so that in equation (3), O and N are not below zero in amount).
2. The device according to claim 1 , wherein the light emitting element emits light having a wavelength of 440 nm to 470 nm.
3. The device according to claim 1 , wherein x2, a2, b2, c2, and d2 satisfy a relationship of 0.01<x2≦0.10, 0.58≦a2≦0.70, 2.1≦b2≦3.5, 0.1≦c2≦0.5, 4.1≦d2≦5.0 in the equation (2).
4. The device according to claim 2 , wherein x2, a2, b2, c2, and d2 satisfy the relationship of 0.01<x2≦0.10, 0.58≦a2≦0.70, 2.1≦b2≦3.5, 0.1≦c2≦0.5, 4.1≦d2≦5.0 in the equation (2).
5. The device according to claim 1 , further comprising a blue phosphor disposed on the light emitting element.
6. The device according to claim 5 , wherein the light emitting element emits light having a wavelength of 380 nm to 420 nm.
7. A device comprising:
a board;
a light emitting element mounted on the board;
a red fluorescent layer formed on the light emitting element, the red fluorescent layer including a first red phosphor having a composition expressed by equation (1) and a second red phosphor having a composition expressed by equation (2), the first red phosphor and the second red phosphor being dispersed in a resin; and
a green fluorescent layer formed on the red fluorescent layer, the green fluorescent layer including a green phosphor dispersed in a resin, the green phosphor having a composition expressed by equation (3),
(Ca 1-x1 Eu x1 ) a1 AlSi b1 O c1 N d1 :Eu (1)
(In the equation (1), x1, a1, b1, c1 and d1 satisfy the following relationship: 0<x1<0.03, 0.90<a1<1.1, 0.90<b1<1.1, 0.20<c1<0.45, 2.40<d1≦3.00)
(Sr 1-x2 Eu x2 ) a2 Si b2 AlO c2 N d2 (2)
(In the equation (2), x2, a2, b2, c2, and d2 satisfy the following relationship: 0<x2<1, 0.55<a2<0.95, 2.0<b2<3.9, 0<c2<0.6, 4<d2<5.7)
(Sr 1-x Eu x ) 3-y Si 13-z Al 3+z O 2+u N 21-w (3)
(In the equation (3), x, y, z, u, and w satisfy the following relationship: 0<x<1, −0.1<y<0.3, −3<z≦1, −3<u−w≦1.5, where −2≦u and w≦21 so that in equation (3), O and N are not below zero in amount).
8. The device according to claim 7 , wherein the light emitting element emits light having a wavelength of 440 nm to 470 nm.
9. The device according to claim 7 , wherein x2, a2, b2, c2, and d2 satisfy a relationship of 0.01<x2≦0.10, 0.58≦a2≦0.70, 2.1≦b2≦3.5, 0.1≦c2≦0.5, 4.1≦d2≦5.0 in the equation (2).
10. The device according to claim 8 , wherein x2, a2, b2, c2, and d2 satisfy a relationship of 0.01<x2≦0.10, 0.58≦a2≦0.70, 2.1≦b2≦3.5, 0.1≦c2≦0.5, 4.1≦d2≦5.0 in the equation (2).
11. The device according to claim 7 , further comprising a blue fluorescent layer formed on the green fluorescent layer, the blue fluorescent layer including a blue phosphor dispersed in a resin.
12. The device according to claim 11 , wherein the light emitting element emits light having a wavelength of 380 nm to 420 nm.
13. The device according to claim 7 , further comprising a transparent resin layer formed between the red fluorescent layer and the green fluorescent layer.
14. A light emitting device comprising:
a board;
a light emitting element mounted on the board;
a first red fluorescent layer formed on the light emitting element, the first red fluorescent layer including a first red phosphor dispersed in a resin, the first red phosphor having a composition expressed by equation (1);
a second red fluorescent layer formed on the first red fluorescent layer, the second red fluorescent layer including a second red phosphor dispersed in a resin, the second red phosphor having a composition expressed by equation (2); and
a green fluorescent layer formed on the second red fluorescent layer, the green fluorescent layer including a green phosphor dispersed in a resin, the green phosphor having a composition expressed by equation (3),
(Ca 1-x1 Eu x1 ) a1 AlSi b1 O c1 N d1 :Eu (1)
(In the equation (1), x1, a1, b1, c1 and d1 satisfy the following relationship: 0<x1<0.03, 0.90<a1<1.1, 0.90<b1<1.1, 0.20<c1<0.45, 2.40<d1≦3.00)
(Sr 1-x2 Eu x2 ) a2 Si b2 AlO c2 N d2 (2)
(In the equation (2), x2, a2, b2, c2, and d2 satisfy the following relationship: 0<x2<1, 0.55<a2<0.95, 2.0<b2<3.9, 0<c2<0.6, 4<d2<5.7)
(Sr 1-x Eu x ) 3-y Si 13-z Al 3+z O 2+u N 21-w (3)
(In the equation (3), x, y, z, u, and w satisfy the following relationship: 0<x<1, −0.1<y<0.3, −3<z≦1, −3<u−w≦1.5, where −2≦u and w≦21 so that in equation (3), O and N are not below zero in amount).
15. The device according to claim 14 , wherein the light emitting element emits light having a wavelength of 440 nm to 470 nm.
16. The device according to claim 14 , wherein x2, a2, b2, c2, and d2 satisfy a relationship of 0.01<x2≦0.10, 0.58≦a2≦0.70, 2.1≦b2≦3.5, 0.1≦c2≦0.5, 4.1≦d≦5.0 in the equation (2).
17. The device according to claim 15 , wherein x2, a2, b2, c2, and d2 satisfy a relationship of 0.01<x2≦0.10, 0.58≦a2≦0.70, 2.1≦b2≦3.5, 0.1≦c2≦0.5, 4.1≦d2≦5.0 in the equation (2).
18. The device according to claim 14 , further comprising a blue fluorescent layer formed on the green fluorescent layer, the blue fluorescent layer including a blue phosphor dispersed in a resin.
19. The device according to claim 18 , wherein the light emitting element emits light having a wavelength of 380 nm to 420 nm.
20. The device according to claim 14 , further comprising a transparent resin layer formed between the second red fluorescent layer and the green fluorescent layer.