IP Library Granted Patent US 8,829,780
Granted Patent B2
US 8,829,780 · App. 13/571,538 · Granted Sep 9, 2014

White semiconductor light emitting device

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Quick Facts
Patent No.
US 8,829,780
App. No.
13/571,538
Granted
Sep 9, 2014
Kind
B2
Abstract

The invention aims at providing controllable parameters that are correlated with special color rendering index R9, and at providing a white-light emitting semiconductor device having a high R9 value obtained through optimization of such parameters. The white-light emitting semiconductor device is provided with a phosphor as a light-emitting material and with a light-emitting semiconductor element as an excitation source of the phosphor. The phosphor includes at least a green phosphor and a wide-band red phosphor. In the white light-emitting semiconductor device, an intensity at wavelength 640 nm of an emission spectrum which has been normalized with respect to luminous flux is 100-110% of the intensity at wavelength 640 nm of a spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

Claims (26)

1. A white light-emitting semiconductor device comprising a phosphor as a light-emitting material, and with a light-emitting semiconductor element as an excitation source of the phosphor, and said phosphor including at least a green phosphor and a wide-band red phosphor,

wherein said green phosphor includes at least one type of green phosphor selected from among a green phosphor that contains a crystal formed of an alkaline earth silicon oxynitride or Sialon as a base and that contains Eu 2+ as an activator, and a green phosphor that contains Ce 3+ as an activator; and

an intensity at wavelength 640 nm of an emission spectrum which has been normalized with respect to luminous flux is 100-110% of the intensity at wavelength 640 nm of a spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

2. The white light-emitting semiconductor device according to claim 1 , wherein the correlated color temperature of emitted white light ranges from 2500 to 3500 K.

3. The white light-emitting semiconductor device according to claim 1 , wherein said green phosphor includes β-Sialon:Eu.

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

an emission peak wavelength of said light-emitting semiconductor element ranges from 360 to 430 nm,

said phosphor further includes a blue phosphor, and

the white light-emitting semiconductor device emits white light that includes light respectively emitted by said blue phosphor, said green phosphor and said wide-band red phosphor.

5. The white light-emitting semiconductor device according to claim 4 , wherein said light-emitting semiconductor element is an InGaN-based LED element, the emission peak wavelength of which ranges from 405 to 415 nm.

6. The white light-emitting semiconductor device according to claim 4 , wherein said blue phosphor includes an alkaline earth halophosphate phosphor activated by Eu 2+ .

7. The white light-emitting semiconductor device according to claim 1 , wherein the emission peak wavelength of said light-emitting semiconductor element ranges from 430 to 470 nm.

8. The white light-emitting semiconductor device according to claim 1 , wherein

said phosphor further includes a yellow phosphor, and

the white light-emitting semiconductor device emits white light that includes at least light respectively emitted by said green phosphor, said yellow phosphor and said wide-band red phosphor.

9. The white light-emitting semiconductor device according to claim 1 , wherein said wide-band red phosphor includes (CaAlSiN 3 ) 1-x (Si (3n+2)/4 N n O) x :Eu.

10. A white light-emitting semiconductor device, comprising:

a first and second white light-emitting units, each of which includes a phosphor as a light-emitting material, and a light-emitting semiconductor element as an excitation source of the phosphor, and said phosphor includes at least a green phosphor and a wide-band red phosphor, wherein

in each of said first and second white light-emitting units, an intensity at wavelength 640 nm of an emission spectrum which has been normalized with respect to luminous flux is 100-110% of the intensity at wavelength 640 nm of a spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux, and

the white light-emitting semiconductor device can emit combined secondary white light resulting from mixing of primary white light emitted by said first white light-emitting unit and primary white light emitted by said second white light-emitting unit.

11. The white light-emitting semiconductor device according to claim 10 , wherein a difference between the correlated color temperature of the primary white light emitted by said first white light-emitting unit and the correlated color temperature of the primary white light emitted by said second white light-emitting unit is 2000 K or more.

12. The white light-emitting semiconductor device according to claim 11 , wherein the correlated color temperature of the primary white light emitted by said first white light-emitting unit ranges from 2500 to 3500 K, and the correlated color temperature of the primary white light emitted by said second white light-emitting unit ranges from 4500 to 7000 K.

13. A white light-emitting semiconductor device having first to N-th white light-emitting units, each of which comprises a phosphor as a light-emitting material, and a light-emitting semiconductor element as an excitation source of the phosphor, and said phosphor includes at least a green phosphor and a wide-band red phosphor, this white light-emitting semiconductor device emitting combined secondary white light resulting from mixing of primary white light respectively emitted by said first to N-th white light-emitting units, wherein

in all or part of said first to N-th white light-emitting units, said green phosphor includes at least one type of green phosphor selected from among a green phosphor that contains a crystal formed of an alkaline earth silicon oxynitride or Sialon as a base and that contains Eu 2+ as an activator, and a green phosphor that contains Ce 3+ as an activator, and

an intensity at wavelength 640 nm of a spectrum of the secondary white light which has been normalized with respect to luminous flux is 100-110% of the intensity at wavelength 640 nm of a spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

14. The white light-emitting semiconductor device according to claim 13 , wherein in all or part of said first to N-th white light-emitting units, the intensity at wavelength 640 nm of the emission spectrum which has been normalized with respect to luminous flux is 99% or less or 111% or more of the intensity at wavelength 640 nm of a spectrum of standard light for color rendering evaluation which has been normalized with respect to luminous flux.

Assignments (4)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 1, 2021
From: MITSUBISHI CHEMICAL CORPORATION
To: CMC MAGNETICS CORPORATION
Reel/Frame 055101/0299 →
CHANGE OF NAME Recorded Sep 5, 2017
From: MITSUBISHI RAYON CO., LTD.
To: MITSUBISHI CHEMICAL CORPORATION
Reel/Frame 043750/0834 →
MERGER Recorded Sep 4, 2017
From: MITSUBISHI CHEMICAL CORPORATION
To: MITSUBISHI RAYON CO., LTD.
Reel/Frame 043750/0207 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 10, 2012
From: SAKUTA, HIROAKI; KAGAWA, KAZUHIKO; SATOU, YOSHIHITO; HIRAOKA, SHIN
To: MITSUBISHI CHEMICAL CORPORATION
Reel/Frame 028765/0635 →