LIGHT EMITTING DEVICE AND LIGHT EMITTING APPARATUS

• US 20100052504A1
• Filed: 08/27/2009
• Published: 03/04/2010
• Est. Priority Date: 08/29/2008
• Status: Active Grant

• Current Assignee: Alpad Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nunoue, Shinya, Sato, Takahiro
• Granted Patent: US 8,207,659 B2
• Time in Patent Office: Days
• US Class Current: 313/483
• CPC Class Codes: C09K 11/02 Use of particular materials as binders, particle coatings or suspension media therefor
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 11/08 containing inorganic luminescent materials
• CPC Class Codes: C09K 2211/1007 Non-condensed systems
• CPC Class Codes: C09K 2211/182 of the rare earth metals, i.e. Sc, Y or lanthanide
• CPC Class Codes: H01L 2224/48091 Arched
• 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 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 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01066 Dysprosium [Dy]
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials

Abstract

A light emitting device, includes: a light source; a first wavelength conversion unit absorbing a light-source light radiated by the light source and radiating a first light, a wavelength of the first light being different from a wavelength of the light-source light; and a second wavelength conversion unit dispersedly provided in the first wavelength conversion unit, the second wavelength conversion unit absorbing the light-source light and radiating a second light. An absorptance of the light-source light in the second wavelength conversion unit is higher than an absorptance of the light-source light in the first wavelength conversion unit. A wavelength of the second light is different from the wavelength of the light-source light and different from the wavelength of the first light.

Claims

1. A light emitting device, comprising:

a light source;

a first wavelength conversion unit absorbing a light-source light radiated by the light source and radiating a first light, a wavelength of the first light being different from a wavelength of the light-source light; and

a second wavelength conversion unit dispersedly provided in the first wavelength conversion unit, the second wavelength conversion unit absorbing the light-source light and radiating a second light,

an absorptance of the light-source light in the second wavelength conversion unit being higher than an absorptance of the light-source light in the first wavelength conversion unit, and

a wavelength of the second light being different from the wavelength of the light-source light and different from the wavelength of the first light.

2. The device according to claim 1, wherein a concentration of the second wavelength conversion unit in the first wavelength conversion unit is higher on a side distal to the light source than on a side proximal to the light source.

3. The device according to claim 1, wherein a portion of the first wavelength conversion unit is disposed on a side farther to the light source than the second wavelength conversion unit.

4. The device according to claim 1, wherein the first wavelength conversion unit includes a fluorescent material in one of a liquid state, an amorphous state and a gel state.

5. The device according to claim 1, wherein the first wavelength conversion unit includes a fluorescent material including a hydrocarbon group.

6. The device according to claim 1, wherein the light source includes a semiconductor light emitting element.

7. The device according to claim 1, wherein a peak light emission wavelength of the light source is in a range of 240 nanometers to 480 nanometers.

8. The device according to claim 1, wherein the wavelength of the second light is longer than the wavelength of the light-source light.

9. The device according to claim 1, wherein the wavelength of the first light is longer than the wavelength of the second light.

10. The device according to claim 1, wherein at least one of the first and second wavelength conversion units include a third wavelength conversion unit absorbing the light-source light and radiating a third light having a wavelength different from the wavelength of the light-source light, the wavelength of the first light, and the wavelength of the second light.

11. The device according to claim 1, further comprising a light transmitting layer provided between the light source and the first wavelength conversion unit and between the light source and the second wavelength conversion unit, the light transmitting layer transmitting the light-source light.

12. The device according to claim 1, further comprising a moisture resisting cover provided on a side of the first and second wavelength conversion units opposite to the light source, the moisture resisting cover protecting at least one of the first and second wavelength conversion units against moisture.

13. The device according to claim 1, wherein the light-source light passes through the first wavelength conversion unit and the second wavelength conversion unit multiple times.

14. The device according to claim 1, wherein the light-source light is a blue light, the first light is a red light, and the second light is a yellow light.

15. The device according to claim 1, wherein the light-source light, the first light, and the second light synthesize to produce a white light.

16. The device according to claim 1, wherein the light source emits light having a wavelength capable of exciting a fluorescent material.

17. The device according to claim 1, wherein the light source is at least one selected from a group consisting of a combustible light source, a discharge tube, an inorganic EL, an organic EL, a semiconductor light emitting element, and a light emitting unit extracting a wavelength region by an optical component, the one emitting an ultraviolet, near-ultraviolet, violet, bluish-violet, or blue light.

18. The device according to claim 1, wherein the second wavelength conversion unit includes at least one selected from a group consisting of:

(Ba, Eu, Sr)(Mg, Mn)Al₁₀O₁₇;

(Ba, Ca, Mg, Sr)₁₀(PO₄)₆Cl₂;

Eu;

(Ba, Ca, Sr)SiO₄;

Eu;

(Ba, Ca, Mg, Sr)AlSiN₃;

Eu;

(Ba, Ca, Sr)₂Si₅N₈;

Eu;

(Ca, Sr)(Al, Ga)₂S₄;

Eu, Tb;

(Y, Gd)₃(Al, Ga)₅O₁₂;

Ce, Eu, Tb;

(Y, La, Gd, Eu)₂(O, S)₃;

Eu, Tb;

(Y, Gd)BO₃;

Ce, Eu;

(Zn, Mn)₂SiO₄;

Mn;

(Mg, Zn, Cd)(O, S, Se);

(Zn, Cd)S;

Ag, Cu, Al;

(Al, Ga, In)(N, P, As);

BaAl₁₂O₁₉;

Mn;

BaMg₂Al₁₆O₂₇;

Eu;

LaPO₄;

Ce, Tb;

SiAl₂O₂N₂;

Eu;

Y₂SiO₅;

Tb; and

YVO₄;

Eu.

19. A light emitting apparatus, comprising:

a light emitting device; and

an electronic circuit,

the light emitting device including;

a light source;

a first wavelength conversion unit absorbing a light-source light radiated by the light source and radiating a first light, a wavelength of the first light being different from a wavelength of the light-source light; and

a second wavelength conversion unit dispersedly provided in the first wavelength conversion unit, the second wavelength conversion unit absorbing the light-source light and radiating a second light,

an absorptance of the light-source light in the second wavelength conversion unit being higher than an absorptance of the light-source light in the first wavelength conversion unit, and

a wavelength of the second light being different from the wavelength of the light-source light and different from the wavelength of the first light, and

the electronic circuit being connected to the light source to supply a current to the light source.

20. The apparatus according to claim 19, wherein the light emitting device further includes a moisture resisting cover provided on a side of the first and second wavelength conversion units opposite to the light source, the moisture resisting cover protecting at least one of the first and second wavelength conversion units against moisture.