Light emitting device

• US 7,247,257 B2
• Filed: 03/21/2006
• Issued: 07/24/2007
• Est. Priority Date: 04/20/2001
• Status: Expired due to Term

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Murazaki, Yoshinori, Ichihara, Takashi
• Primary Examiner(s): Koslow; C. Melissa
• Application Number:
  US11/384,548
• Publication Number:
  US 20060163999A1
• Time in Patent Office: 490 Days
• Field of Search: 257/98, 313/503, 252/301.4 P, 252/301.4 H, 252/301.6 P
• US Class Current: 252/301.40P
• CPC Class Codes: C09K 11/584 with zinc or cadmium
• CPC Class Codes: C09K 11/662 with zinc or cadmium
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/7739 with halogens
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: C09K 11/7789 Oxysulfides
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45139 Silver (Ag) as principal constituent
• 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 2224/4903 Connectors having different sizes, e.g. different diameters
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• 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 2924/00011 Not 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 2924/01005 Boron [B]
• CPC Class Codes: H01L 2924/207 Diameter ranges
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H05B 33/14 : characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source

Abstract

To minimize the variability in the emitted light color and improve the unevenness of color tone, a light emitting device comprises a light emitting element and a fluorescent substance that is excited by the light emitting element, wherein the light emitting element has an emission spectrum in a region from ultraviolet to visible light of short wavelengths, and the fluorescent substance has an emission spectrum that includes two or more emission peaks with at least two peaks of the two or more peaks being in the relation of complementary colors of each other.

Claims

1. A white light emitting device comprising:

a light emitting element,

a first fluorescent substance having a peak wavelength in a range from 575 nm to 630 nm,

a second fluorescent substance capable of emitting a light in a range from blue to red, said second fluorescent substance being different from the first fluorescent substance, said second fluorescent substance being represented by (M_1-a-bEu_aL1_b)₁₀(PO₄)₆Q₂ (M representing at least one kind of element selected from Mg, Ca, Ba, Sr and Zn;

L1 representing at least one kind of element selected from Mn, Fe, Cr and Sn; and

Q representing at least one kind of halogen element selected from F, Cl, Br and I, where 0.0001 ≦

a≦

0.5 and 0.0001 ≦

b≦

0.5).

2. The white light emitting device according to claim 1,

wherein a light outputted from the device is not including a visible component of the light outputted from the light emitting element.

3. The white light emitting device according to claim 1,

wherein the light outputted from the light emitting element has a wavelength in a range from 340 nm to 440 nm.

4. The white light emitting device according to claim 1,

wherein the light emitting element has an active layer of InGaN.

5. The white light emitting device according to claim 1,

wherein said first fluorescent substance has another peak wavelength in a range from 380 nm to 485 nm.

6. The white light emitting device according to claim 1,

wherein said first fluorescent substance comprises Eu and Mn.

7. The white light emitting device according to claim 1,

wherein said first fluorescent substance comprises at least one selected from the group consisting of Mg, Ca, Ba, Sr and Zn.