Light emitting device and display

• US 6,608,332 B2
• Filed: 12/15/2000
• Issued: 08/19/2003
• Est. Priority Date: 07/29/1996
• Status: Expired due to Term

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Kagaku Kogyo Kabushiki Kaisha
• Inventors: Shimizu, Yoshinori, Moriguchi, Toshio, Sakano, Kensho, Noguchi, Yasunobu
• Primary Examiner(s): CRANE, SARA W
• Application Number:
  US09/736,425
• Publication Number:
  US 20010001207A1
• Time in Patent Office: 977 Days
• Field of Search: 257/85, 257/89, 257/90, 257/94, 257/95, 257/96, 257/98, 257/99, 257/103, 349/62, 359/599, 362/31, 362/330, 362/336
• 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 to emit light;

an optical guide member; and

a coating containing a color converting material,

wherein said light source comprises a nitride compound semiconductor represented by the formula;

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:

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 is arranged in a C-shaped enclosure in the outer vicinity of said first surface of said optical guide member.

6. A light source system according to claim 1, further comprising a light scattering sheet arranged on said second surface of said optical guide member.

7. A light source system according to claim 5, wherein said coating is formed by mixing said color converting material with epoxy resin.

8. A light source system according to claim 5, wherein said coating is applied to the C-shaped enclosure.

9. A light source system according to claim 6, wherein said coating is formed by spreading a binder with said color converting material over the scattering sheet.

10. A light source system according to claim 1, wherein said coating is formed in dots or sheet directly on said optical guide member.

11. A light source system according to claim 6, wherein said scattering sheet contains said color converting material.

12. A light source system according to claim 1, wherein said optical guide member is provided with reflectors on a third surface opposing said second surface of said optical guide member or on a fourth surface opposing the light source.

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, wherein said light source includes a light emitting component in the form of a light emitting diode (LED) for emitting a first color light,

wherein said optical guide member includes a light emitting plate or lens for receiving light at one of its faces and emitting light from a different one of its faces,

wherein said coating containing the color converting material is positioned between said LED and said optical guide member,

wherein said color converting material changes a part of the light from said LED into light of a different color, and

transmits another part of the light from said LED unaffected, and

wherein said light emitting plate or lens mixes the two parts of said light from said coating containing the color converting material, and emits the mixed light from a main face of said light emitting plate or lens.

16. A light source system according to claim 1, wherein said coating covers said light source disposed in the outer vicinity of said first surface of said optical guide member and is further spread out entirely on said first surface of said optical guide member.

15. A display device, comprising:

a light emitting component in the form of a light emitting diode (LED) for emitting a first color light; and

a light emitting plate for receiving the light from the LED at a first face and emitting light at a different second face,

wherein an element containing a phosphor is positioned between said LED and said light emitting plate, so as

to make a part of the emitted light from said LED change into a different color, and

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

wherein said light emitting plate is adapted to mix parts of the light injected from said element and to emit the mixed light from said second face of said light emitting plate in a planar state.

17. A display device according to claim 15, wherein said LED is arranged in a C-shaped enclosure.

18. A display device according to claim 15, wherein said first color light is a blue light and the mixed light is a white light.