WHITE LIGHT-EMITTING DEVICE, METHOD FOR MANUFACTURING SAME, BACKLIGHT USING SAME, AND LIQUID CRYSTAL DISPLAY

• US 20090154195A1
• Filed: 09/28/2006
• Published: 06/18/2009
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: Seoul Semiconductor Co., Ltd.
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Materials Company Limited (Toshiba Corporation)
• Inventors: Takeuchi, Hajime, Shirakawa, Yasuhiro, Ooya, Yasumasa, Ishii, Tsutomu, Sakai, Ryo
• Granted Patent: US 7,936,418 B2
• Time in Patent Office: Days
• US Class Current: 362/612
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/7739 with halogens
• CPC Class Codes: C09K 11/7789 Oxysulfides
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: H01L 2224/48091 Arched
• 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 2924/00014 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 33/60 Reflective elements
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A white light-emitting device 1 includes a semiconductor light-emitting element 2 emitting ultraviolet light or violet light, and a light-emitting unit 10 which includes three or more kinds of visible light-emitting phosphors 9 and emits white light when excited by the light from the semiconductor light-emitting element 2. The emission spectrum of the light-emitting unit 10 has peaks in a blue region of not less than 440 nm nor more than 460 nm, a green region of not less than 510 nm nor more than 530 nm, and a red region of not less than 620 nm nor more than 640 nm, and the three or more kinds of visible light-emitting phosphors 9 are bound together with a binder in advance.

Claims

1. A white light-emitting device, comprising:

a semiconductor light-emitting element emitting ultraviolet light or violet light; and

a light-emitting unit, which is excited by the light from the semiconductor light-emitting element to emit white light, including three or more kinds of visible light-emitting phosphors,

wherein emission spectrum of the light-emitting unit has peaks in a blue region of not less than 440 nm nor more than 460 nm, a green region of not less than 510 nm nor more than 530 nm, and a red region of not less than 620 nm nor more than 640 nm, and the three or more kinds of visible light-emitting phosphors are bound together with a binder in advance.

2. The white light-emitting device as set forth in claim 1,

wherein a half width of each of the peaks in the blue region, the green region and the red region is 50 nm or less.

3. The white light-emitting device as set forth in claim 1,

wherein the visible light-emitting phosphors include, as a blue light-emitting phosphor, a europium-activated halo-phosphate phosphor having a composition which is represented by the general formula:

(Sr_1-x-yBa_xCa_yEu_z)₁₀(PO₄)₆.Cl₂

(where, x, y and z are numbers satisfying x<

0.2, y<

0.1, 0.005<

z<

0.1).

4. The white light-emitting device as set forth in claim 1,

wherein the visible light-emitting phosphors include, as a green light-emitting phosphor, a europium and manganese-activated aluminate phosphor having a composition which is represented by the general formula:

(Ba_1-x-y-zSr_xCa_yEu_z)(Mg_1-uMn_u)Al₁₀O₁₇

(where, x, y and z are numbers satisfying x<

0.5, y<

0.1, 0.15<

z<

0.4, 0.3<

u<

0.6).

5. The white light-emitting device as set forth in claim 1,

wherein the visible light-emitting phosphors include, as a red light-emitting phosphor, a europium-activated lanthanum oxysulfide phosphor having a composition which is represented by the general formula:

(La_1-x-yEu_xM_y)₂O₂S

(where, M shows at least one of element selected from Sb and Sn, and x and y are numbers satisfying 0.01<

x<

0.15, y<

0.03).

6. The white light-emitting device as set forth in claim 1,

wherein the visible light-emitting phosphors include 10 mass % to 30 mass % of blue light-emitting phosphor, 10 mass % to 30 mass % of green light-emitting phosphor, and 50 mass % to 80 mass % of red light-emitting phosphor.

7. The white light-emitting device as set forth in claim 1,

wherein the semiconductor light-emitting element has a peak value of an emission wavelength of not less than 370 nm nor more than 410 nm.

8. The white light-emitting device as set forth in claim 1,

wherein the semiconductor light-emitting element includes a light-emitting diode or a laser diode.

9. The white light-emitting device as set forth in claim 1,

wherein the light-emitting unit has a resin layer in which the bound three or more kinds of visible light-emitting phosphors are dispersed.

10. The white light-emitting device as set forth in claim 1,

wherein both an average primary particle size before bonding and an average secondary particle size after bonding of the three or more kinds of visible light-emitting phosphors are 7 μ

m or more.

18. A backlight, comprising:

a substrate; and

a white light-emitting device as set forth in claim 1 mounted on the substrate.

19. The backlight as set forth in claim 18, further comprising:

a plurality of the white light-emitting devices arranged in line or in matrix on the substrate.

20. A liquid crystal display device comprising:

a backlight as set forth in claim 18; and

a liquid crystal display unit disposed on a light-emitting surface side of the backlight.

21. The liquid crystal display device as set forth in claim 20,

wherein the backlight comprises a plurality of the white light-emitting devices arranged in matrix and is disposed directly below the liquid crystal display unit.

22. The liquid crystal display device as set forth in claim 20,

wherein the liquid crystal display unit is disposed on an optical waveguide, and the backlight comprises a plurality of the white light-emitting devices arranged in line and is disposed on one end portion of the optical waveguide.

11. A method of manufacturing a white light-emitting device, comprising:

preparing three or more kinds of visible light-emitting phosphors adjusted to have emission spectrum of white light emission exhibiting peaks in a blue region of not less than 440 nm nor more than 460 nm, a green region of not less than 510 nm nor more than 530 nm, and a red region of not less than 620 nm nor more than 640 nm;

binding the three or more kinds of visible light-emitting phosphors with a binder; and

forming a light-emitting unit including the bound three or more kinds of visible light-emitting phosphors, in a light-emitting direction of a semiconductor light-emitting element emitting ultraviolet light or violet light.

12. The method of manufacturing a white light-emitting device as set forth in claim 11,

wherein a half width of each of the peaks in the blue region, the green region and the red region is 50 nm or less.

13. The method of manufacturing a white light-emitting device as set forth in claim 11,

wherein the visible light-emitting phosphors include, as a blue light-emitting phosphor, a europium-activated halo-phosphate phosphor having a composition which is represented by the general formula:

(Sr_1-x-yBa_xCa_yEu_z)₁₀(PO₄)₆.Cl₂

(where, x, y and z are numbers satisfying x<

0.2, y<

0.1, 0.005<

z<

0.1).

14. The method of manufacturing a white light-emitting device as set forth in claim 11,

wherein the visible light-emitting phosphors include, as a green light-emitting phosphor, a europium and manganese-activated aluminate phosphor having a composition which is represented by the general formula:

(Ba_1-x-y-zSr_xCa_yEu_z)(Mg_1-uMn_u) Al₁₀O₁₇

(where, x, y and z are numbers satisfying x<

0.5, y<

0.1, 0.15<

z<

0.4, 0.3<

u<

0.6).

15. The method of manufacturing a white light-emitting device as set forth in claim 11,

wherein the visible light-emitting phosphors include, as a red light-emitting phosphor, a europium-activated lanthanum oxysulfide phosphor having a composition which is represented by the general formula:

(La_1-x-yEu_xM_y)₂O₂S

(where, M shows at least one of element selected from Sb and Sn, and x and y are numbers satisfying 0.01<

x<

0.15, y<

0.03).

16. The method of manufacturing a white light-emitting device as set forth in claim 11,

wherein the visible light-emitting phosphors include 10 mass % to 30 mass % of blue light-emitting phosphor, 10 mass % to 30 mass % of green light-emitting phosphor, and 50 mass % to 80 mass % of red light-emitting phosphor.

17. The method of manufacturing a white light-emitting device as set forth in claim 11,

wherein the bound three or more kinds of visible light-emitting phosphors are dispersed in a resin to form the light-emitting unit.