White light source system

Patent metadata

Field	Value
Publication number	US-10473274-B2
Application number	US-201715849346-A
Country	US
Kind code	B2
Filing date	Dec 20, 2017
Priority date	Jun 24, 2015
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

According to one embodiment, there is provided a white light source system including white light sources. An absolute value of a difference between (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) and (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) for each of the white light sources satisfies a relational expression represented by

|(( P (λ)× V (λ))/( P (λmax1)× V (λmax1))−( B (λ)× V (λ))/( B (λmax2)× V (λmax2))|≤0.15

The white light source system has a light emission characteristic of white light emitted by the system is continuously changed along with an elapse of time by changing a mixing ratio of light beams from the white light sources.

First claim

What is claimed is:

1. A white light source system comprising white light sources each having a general color rendering index of not less than 97,
wherein an absolute value of a difference between (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) and (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) for each of the white light sources satisfies a relational expression represented by
|(( P (λ)× V (λ))/( P (λmax1)× V (λmax1))−( B (λ)× V (λ))/( B (λmax2)× V (λmax2))|≤0.15

where the P(λ) is an emission spectrum of the each white light source, the B(λ) is an emission spectrum of black-body radiation having a color temperature corresponding to a color temperature of the each white light source, the V(λ) is a spectrum of a spectral luminous efficiency, the λmax1 is a wavelength that maximizes P(λ)×V(λ), and the λmax2 is a wavelength that maximizes B(λ)×V(λ),
wherein the white light source system has a light emission characteristic of white light emitted by the system is continuously changed along with an elapse of time by changing a mixing ratio of light beams from the white light sources.

2. The white light source system according to claim 1 , wherein a time-rate change in the light emission characteristic of the white light progresses in accordance with a pattern selected from change patterns based on a result of actual measurement of a change in sunbeams in one day.

3. The white light source system according to claim 2 , wherein the change patterns include a change pattern that changes on a period basis and a change pattern that changes on a location basis, and the pattern can be selected from the change patterns on a season basis or depending on a latitude or a longitude.

4. The white light source system according to claim 1 , wherein the white light sources comprise at least three types of white light sources which satisfy the relational expression and have different color temperatures, and two types of white light sources are selected from the at least three types of white light sources and have different color temperatures in a descending order or ascending order and mixed, thereby obtaining, as the white light emitted by the system, a white light having a color temperature based on a black body locus of 2000 K to 6500 K and a deviation with respect to the color temperature is not more than ±0.005 duv.

5. The white light source system according to claim 4 , wherein the white light sources comprise three types of white light sources having different color temperatures.

6. The white light source system according to claim 5 , wherein in the three types of white light sources, a white light source having a highest color temperature has a color temperature of not more than 6500 K, a white light source having a lowest color temperature has a color temperature of not less than 2000 K, and a white light source having an intermediate color temperature between the color temperatures has a color temperature ranging from 2950 K to 4050 K.

7. The white light source system according to claim 2 , wherein the white light sources comprise at least three types of white light sources which satisfy the relational expression and have different color temperatures, and two types of white light sources are selected from the at least three types of white light sources and have different color temperatures in a descending order or ascending order and mixed, thereby obtaining, as the white light emitted by the system, a white light having a color temperature based on a black body locus of 2000 K to 6500 K and a deviation with respect to the color temperature is not more than ±0.005 duv.

8. The white light source system according to claim 1 , wherein the each white light source includes a light emitting diode and a phosphor, the light emitting diode emits ultraviolet or violet primary light having a peak wavelength of 350 nm to 420 nm, and the phosphor absorbs the primary light from the light emitting diode and converts the primary light into a white secondary light.

9. The white light source system according to claim 8 , wherein the phosphor is formed by mixing at least three types of phosphors selected from the group consisting of a blue emitting phosphor, a green emitting phosphor, a yellow emitting phosphor, and a red emitting phosphor.

10. The white light source system according to claim 9 , wherein the phosphor is formed by mixing the blue emitting phosphor at a ratio of 45 parts by weight to 75 parts by weight, the green light emitting phosphor at a ratio of 3 parts by weight to 7 parts by weight, the yellow light emitting phosphor at a ratio of 9 parts by weight to 17 parts by weight, and the red phosphor at a ratio of 9 parts by weight to 18 parts, and a total amount of the phosphors is 100 parts by weight.

11. The white light source system according to claim 10 , wherein the blue emitting phosphor is a europium activated alkaline earth phosphate phosphor, the green emitting phosphor is a europium and manganese activated alkaline earth magnesium silicate phosphor, the yellow emitting phosphor is a europium and manganese activated alkaline earth magnesium silicate phosphor, and the red emitting phosphor is a europium activated calcium nitridoaluminosilicate phosphor.

12. The white light source system according to claim 9 , wherein the blue emitting phosphor is a europium activated alkaline earth phosphate phosphor, the green emitting phosphor is a europium and manganese activated alkaline earth magnesium silicate phosphor, the yellow emitting phosphor is a europium and manganese activated alkaline earth magnesium silicate phosphor, and the red emitting phosphor is a europium activated calcium nitridoaluminosilicate phosphor.

Assignees

• Toshiba Kk
• Toshiba Materials Co Ltd

Inventors

• Yamakawa Masahiko
• Tsuda Ryoji
• Ooya Yasumasa
• Itoga Tatsunori
• Shirakawa Yasuhiro
• Taniguchi Junji

Classifications

• H05B33/10 Primary

  Apparatus or processes specially adapted to the manufacture of electroluminescent light sources · CPC title

• H05B47/10

  Controlling the light source · CPC title

• H05B45/20

  Controlling the colour of the light · CPC title

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title

• C09K11/64

  containing aluminium · CPC title