Light emitting device

• US 8,471,277 B2
• Filed: 08/22/2011
• Issued: 06/25/2013
• Est. Priority Date: 09/08/2010
• Status: Expired due to Fees

• Current Assignee: Alpad Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Mitsuishi, Iwao, Nunoue, Shinya, Sato, Takahiro, Fukuda, Yumi, Okada, Aoi, Matsuda, Naotoshi, Hikosaka, Toshiki, Albessard, Keiko, Kato, Masahiro
• Primary Examiner(s): Monbleau, Davienne
• Assistant Examiner(s): Hossain, Moazzam
• Application Number:
  US13/214,377
• Publication Number:
  US 20120056224A1
• Time in Patent Office: 673 Days
• Field of Search: None
• US Class Current: 257/89
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/00014 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 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil

Abstract

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.

Claims

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-x1Eu_x1)_a1AlSi_b1O_c1N_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-x2Eu_x2)_a2Si_b2AlO_c2N_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-xEu_x)_3-ySi_13-zAl_3+zO_2+uN_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-x1Eu_x1)_a1AlSi_b1O_c1N_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-x2Eu_x2)_a2Si_b2AlO_c2N_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-xEu_x)_3-ySi_13-zAl_3+zO_2+uN_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-x1Eu_x1)_a1AlSi_b1O_c1N_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-x2Eu_x2)_a2Si_b2AlO_c2N_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-xEu_x)_3-ySi_13-zAl_3+zO_2+uN_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.