Light Emitting Device, and Lighting System, Image Display Using the Same

• US 20080290786A1
• Filed: 06/29/2005
• Published: 11/27/2008
• Est. Priority Date: 06/30/2004
• Status: Abandoned Application

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Inventors: Kijima, Naoto, Shimomura, Yasuo, Kaneda, Hideaki
• Application Number:
  US11/631,103
• Publication Number:
  US 20080290786A1
• Time in Patent Office: Days
• US Class Current: 313/503
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/64 containing aluminium
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: C09K 11/77742 Silicates
• 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 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: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces

Abstract

To enhance luminance and color rendering of a light emitting device comprising phosphors as wavelength converting material and at least one semiconductor light emitting device that emits visible light, as said phosphors, are used phosphors which are one or more kinds of phosphors selected from a group consisting of oxides, oxynitrides and nitrides, and are a mixture consisting of two or more kinds of phosphors whose luminous efficiency is 35% or higher when excited by the visible light from said semiconductor light emitting device at room temperature. In addition, said mixture contains a first phosphor, and a second phosphor that is different from said first phosphor and capable of absorbing emitted light from said first phosphor, and said first phosphor is contained 85 weight % or more of said mixture of phosphors.

Claims

1. A light emitting device comprising:

phosphors as wavelength converting material and

at least one semiconductor light emitting device that emits visible light,

wherein said phosphors are one or more kinds of phosphors selected from a group consisting of oxides oxynitrides and nitrides, and are a mixture consisting of two or more kinds of phosphors whose luminous efficiency is 35% or higher when excited by the visible light from said semiconductor light emitting device at room temperature; and

said mixture contains a first phosphor, and a second phosphor that is different from said first phosphor and capable of absorbing emitted light from said first phosphor and said first phosphor is contained 85 weight % or more of said mixture of phosphors.

2. A light emitting device as defined in claim 1, wherein the mission peak wavelength L1 of said first phosphor is in the range of 490 nm≦

L1≦

550 nm and the emission peak wavelength L2 of said second phosphor is in the range of 600 nm≦

L2≦

700 nm.

3. A light emitting device as defined in claim 1, wherein the device contains a mixture of phosphors whose color coordinate (x, y) of the emitted light from said mixture of phosphors, when it is irradiated by the emitted light from said semi conductor light emitting device, is in the range surrounded by the quadrangle with apexes having CIE color coordinates (0.450, 0.350), (0.550, 0.450), (0.400, 0.600), and (0.300, 0.500).

4. A light emitting device as defined in claim 1, wherein the color coordinate of a composite light consisting of emitted light from said semiconductor light emitting device and emitted light from said mixture of phosphors that is excited by the emitted light from said semiconductor light emitting device, is in the range surrounded by the quadrangle with apexes having CIE color coordinates (0.275, 0.175), (0.450, 0.400), (0.350, 0.450), and (0.175, 0.250).

5. A lighting system wherein said lighting system uses said light emitting device as defined in claim 1.

6. A display, wherein said display uses said light emitting device as defined in claim 1.