White light source and white light source system including the same

• US 9,112,120 B2
• Filed: 04/18/2011
• Issued: 08/18/2015
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: Seoul Semiconductor Co., Ltd.
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Materials Company Limited (Toshiba Corporation)
• Inventors: Yamakawa, Masahiko, Shirakawa, Yasuhiro
• Primary Examiner(s): Movva, Amar
• Application Number:
  US13/983,378
• Publication Number:
  US 20130307011A1
• Time in Patent Office: 1,583 Days
• US Class Current: 1/1
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21V 3/10 characterised by coatings
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/501 characterised by the materials, e.g. binder
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H05B 33/10 Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
• 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

The present invention provides a white light source satisfying a relational equation of
−0.2≦[(P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2)×V(λmax2))]≦+0.2,

assuming that: a light emission spectrum of the white light source is P(λ); a light emission spectrum of black-body radiation having a same color temperature as that of the white light source is B(λ); a spectrum of a spectral luminous efficiency is V(λ); a wavelength at which P(λ)×V(λ) becomes largest is λmax1; and a wavelength at which B(λ)×V(λ) becomes largest is λmax2. According to the above white light source, there can be provided a white light source capable of reproducing the same light emission spectrum as that of natural light.

Claims

1. A white light source satisfying a relational equation of

−

0.2≦

[(P(λ

)×

V(λ

))/(P(λ

max1)×

V(λ

max1))−

(B(λ

)×

V(λ

))/(B(λ

max2)×

V(λ

max2))]≦

+0.2,

assuming that;

a light emission spectrum of the white light source is P(λ

);

a light emission spectrum of black-body radiation having a same color temperature as that of the white light source is B(λ

);

a spectrum of a spectral luminous efficiency is V(λ

);

a wavelength at which P(λ

)×

V(λ

) becomes largest is λ

max1; and

a wavelength at which B(λ

)×

V(λ

) becomes largest is λ

max2.

2. The white light source according to claim 1, satisfying −

0.1≦

[(P(λ

)×

V(λ

))/(P(λ

max1)×

V(λ

max1))−

(B(λ

)×

V(λ

))/(B(λ

max2)×

V(λ

max2))]≦

+0.1.

3. The white light source according to claim 1, wherein the color temperature of the white light source is 2,500 to 7,000 K.

4. The white light source according to claim 1, comprising an LED and a phosphor.

5. The white light source according to claim 4, wherein

the LED has a light emission peak in a range of 350 to 420 nm, and

the phosphor has at least one light emission peak in a range of 420 to 700 nm.

6. The white light source according to claim 4, comprising three or more types of phosphors having different peak wavelengths.

7. The white light source according to claim 4, comprising five or more types of phosphors having different peak wavelengths.

8. The white light source according to claim 4, wherein the phosphors are mixed with a resin to form a phosphor layer.

9. The white light source according to claim 4, wherein adjacent peak wavelengths of the phosphors are different by 150 nm or less.

10. The white light source according to claim 8, wherein the phosphor layer has a multi-layered structure.

11. The white light source according to claim 4, the phosphor comprises at least one phosphor selected from the group consisting of:

europium-activated alkaline earth phosphate phosphor having a peak wavelength of 440 to 455 nm;

europium-activated barium magnesium aluminate phosphor having a peak wavelength of 450 to 460 nm;

europium-activated strontium aluminate phosphor having a peak wavelength of 480 to 500 nm;

europium- and manganeses-activated barium magnesium aluminate phosphor having a peak wavelength of 510 to 520 nm;

europium-activated orthosilicate phosphor having a peak wavelength of 520 to 550 nm;

europium-activated β

-sialon phosphor having a peak wavelength of 535 to 545 nm;

europium-activated strontium sialon phosphor having a peak wavelength of 510 to 530 nm;

europium-activated orthosilicate phosphor having a peak wavelength of 550 to 580 nm;

cerium-activated rare-earth aluminum garnet phosphor having a peak wavelength of 550 to 580 nm;

europium-activated strontium sialon phosphor having a peak wavelength of 600 to 630 nm;

europium-activated calcium strontium oxynitride phosphor having a peak wavelength of 610 to 650 nm;

europium-activated lanthanum oxysulfide phosphor having a peak wavelength of 620 to 630 nm; and

manganese-activated magnesium fluorogermanate having a peak wavelength of 640 to 660 nm.

12. The white light source according to claim 6, the phosphors have an average particle size of 5 to 40 μ

m.

13. A white light source system comprising a plurality of the white light sources according to claim 1.