Light emitting device and display

• US 20010001207A1
• Filed: 12/15/2000
• Published: 05/17/2001
• Est. Priority Date: 07/29/1996
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Kagaku Kogyo Kabushiki Kaisha
• Inventors: Shimizu, Yoshinori, Moriguchi, Toshio, Sakano, Kensho, Noguchi, Yasunobu
• Granted Patent: US 6,608,332 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: H01L 2224/45144 Gold (Au) 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 2224/8592 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 2924/01021 Scandium [Sc]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/181 Encapsulation
• 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

The white light emitting diode comprising a light emitting component using a semiconductor as a light emitting layer and a phosphor which absorbs a part of light emitted by the light emitting component and emits light of wavelength different from that of the absorbed light, wherein the light emitting layer of the light emitting component is a nitride compound semiconductor and the phosphor contains garnet fluorescent material activated with cerium which contains at least one element selected from the group consisting of Y, Lu, Sc, La, Gd and Sm, and at least one element selected from the group consisting of Al, Ga and In and, and is subject to less deterioration of emission characteristic even when used with high luminance for a long period of time.

Claims

1. A light source system comprising

a light source (702),

an optical guide plate or lens (704) and/or

a coating (701, 710) containing a color converting material,

wherein said light source (702) comprises a nitride compound semiconductor represented by the formula

IN_iGa_jAl_kN

where

0≦

i,

0≦

j,

0≦

k and

i+j+k=1

including InGaN and GaN

doped with various impurities

emitting blue light

with a main emission peak set within the range from 400 nm to 530 nm, wherein said optical guide plate or lens (704) and/or said coating (701, 710) filter(s) by absorption a first part of the blue light coming from said light source (702),

transmit(s) a second part of the blue light coming from said light source (702),

convert(s) the absorbed blue light to a new light of longer wavelength and

blend(s) this new light to the transmitted part of the blue light coming from said light source (702),

so as to radiate a light combination; and

wherein said optical guide plate or lens (704) is used to receive light on one surface and to emit light in a planar state at an other surface.

2. A light source system according to

claim 1

,

wherein said color converting material consists of one, two or more garnet fluorescent materials according to the general formula

(Re₁₋

rSm_r)₃(Al<sub>1−

s</sub>Ga₃)₅O₂;

Ce

where

0≦

r<

1

0≦

s≦

1

Re is at least one selected from Y and Gd, and where

at least one material contained in the color converting material has r≠

0.

3. A light source system according to

claim 1

, wherein said main emission peak of said nitride compound semiconductor is set within the range of 420 nm to 490 nm.

4. A light source system according to

claim 1

, wherein said light combination is white.

5. A light source system according to

claim 1

, wherein said light source (702) is arranged in a C-shape d enclosure (703).

6. A light source system according to

claim 1

, wherein a light scattering sheet (706) is arranged on the light emitting surface of said optical guide plate (704).

7. A light source system according to

claim 1

, wherein the layer or coating (701) is formed by mixing said color converting material to epoxy resin.

8. A light source system regarding to

claim 1

, wherein said coating (701) is applied to the C-shaped enclosure (703).

9. A light source system according to

claim 1

, wherein said coating (701) is formed by spreading a binder with said color converting material over the scattering sheet (706).

10. A light source system according to

claim 1

, wherein said coating (701) is formed in dots or sheet directly on said optical guide plate or lens (704).

11. A light source system according to

claim 1

, wherein said scattering sheet (706) contains said color converting material.

12. A light source system according to

claim 1

, wherein said optical guide plate or lens (704) is provided with reflectors (705) on the entire surface opposing the emitting surface and/or on the end surface opposing the light emitting component (702).

13. A light source system according to

claim 1

, wherein said light source system is used to illuminate a liquid crystal display.

14. A light source system according to

claim 1

, comprising

a light emitting component (702) inform of a light emitting diode LED for emitting a first color light,

a light emitting plate or lens (704) for receiving light at one of it'"'"'s faces and emitting light from a different one of it'"'"'s faces,

wherein an element (701) containing a color converting material is positioned between said LED light emitting component (702) and

wherein said color converting material of said element (701)

changes a part of the light from said LED light emitting component (702) into light of a different color and

transmits an other part of the light from said LED light emitting component (702) unaffected, and

wherein said light emitting plate or lens (704)

mixes the two parts of said light from said element (701) containing color converting material and

emits the mixed light from the main face.

15. A display device, comprising

a light emitting component in form of a light emitting diode LED (702) for emitting a first color light, and

a light emitting plate (704) for receiving light at one of it'"'"'s faces and emitting light from a different one of it'"'"'s faces,

wherein an element (701) containing a phosphor is positioned between said LED light emitting component (702) and said light emitting plate (704), so as

to make a part of the emitted light from said LED light emitting component (702) change into a different color and

to make remainder of the emitted light pass through said element (701) without change, and

said light emitting plate (704) being adapted to mix parts of the light injected from said element (701) and to emit the mixed light from the main face of said light emitting plate (704).