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1. US20190159313 - White light source system

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[ EN ]

Claims

1. A white light source configured to be capable of reproducing white light of a color temperature of 2000 K to 6500 K on a locus of blackbody radiation, and white light of any one of correlated color temperatures with a deviation from the color temperature of the white light being in a range of ±0.005 duv,
wherein P(λ), B(λ) and V(λ) satisfy an equation (1) below in a wavelength range in which λ is 380 nm to 780 nm, and the white light source satisfies an expression (2) below in a wavelength range of 400 nm to 495 nm:

(NB)
where P(λ) is a light emission spectrum of the white light emitted from the white light source, B(λ) is a light emission spectrum of blackbody radiation of a color temperature correspond to a color temperature of the white light, and V(λ) is a spectrum of a spectral luminous efficiency, and
wherein an average color rendering index Ra of the white light emitted from the white light source is 97 or more, and all of color rendering indexes R 1 to R 8 and special color rendering indexes R 9 to R 15 are 90 or more.
2. The white light source of claim 1, wherein a chromaticity variation of the white light source after continuous lighting of 6000 hours is expressed as a variation of chromaticity on a CIE chromaticity diagram, and 0.01 or less.
3. The white light source of claim 1, which comprises an LED configured to emit primary light of ultraviolet to violet with a light emission peak wavelength of 360 nm to 420 nm, and a phosphor configured to absorb the primary light from the LED and to emit secondary light of white.
4. The white light source of claim 3, wherein the phosphor is a mixture of at least two kinds of phosphors which comprises a phosphor configured to absorb as a secondary light light emitted from another phosphor and to emit as a tertiary light another light.
5. The white light source of claim 4, wherein the phosphor is a mixture of at least three kinds of phosphors selected from among a blue phosphor, a green phosphor, a yellow phosphor and a red phosphor.
6. The white light source of claim 5, wherein a blue-green phosphor is further contained in the mixture of phosphors.
7. The white light source of claim 4, wherein each phosphor included in the mixture of the phosphors has a peak wavelength of a light emission spectrum, and an interval between each peak wavelength and a neighboring peak wavelength is 150 nm or less.
8. The white light source of claim 4, wherein each phosphor included in the mixture of the phosphors exhibits a light emission spectrum having a half-value width of 50 nm or more.
9. A white light source system comprising a plurality of the white light source according to claim 1.
10. The white light source system of claim 9, wherein light emission characteristics of white light emitted from the white light source system successively vary from time to time, and
a color temperature of the white light varies from time to time, in such a manner that a difference in the color temperature of the white light is in a range of a shape of MacAdam ellipse.
11. The white light source system of claim 10, wherein variations of sunlight in any range of sunrise to sunset in an arbitrary place on the earth, is reproduced as the variations in the light emission characteristics.
12. The white light source system of claim 9, comprising a white light source unit which comprises first, second, third and fourth LED modules configured to emit white light, and a controller configured to control light emission intensities of the first, second, third and fourth LED modules, and
wherein a white light emitted from the white light source unit has a correlated color temperature correspond to a chromaticity point on a CIE chromaticity diagram with a deviation in a range of ±0.005 duv. from the locus of blackbody radiation,
a first white light emitted from the first LED module and a second white light emitted from the second LED module have a first correlated color temperature,
a third white light emitted from the third LED module and a fourth white light emitted from the fourth LED module have a second correlated color temperature higher than the first correlated color temperature,
the first white light has a first chromaticity point on the CIE chromaticity diagram with a deviation in a range of 0 to +0.005 duv. from the locus of blackbody radiation, and the third white light has a third chromaticity point on the CIE chromaticity diagram with a deviation in a range of 0 to +0.005 duv. from the locus of blackbody radiation,
the second white light has a second chromaticity point on the CIE chromaticity diagram with a deviation in a range of −0.005 to 0 duv. from the locus of blackbody radiation, and the fourth white light has a fourth chromaticity point on the CIE chromaticity diagram with a deviation in a range of −0.005 to 0 duv. from the locus of blackbody radiation, and
wherein the controller comprises a memory unit, a control unit, a data input/output unit and an electronic circuit,
the memory unit is configured to store, with respect to each of dates and each of times, first data on a light emission spectrum of sunlight with respect to places in the USA and places outside the USA;
second data on a correlated color temperature of the sunlight; and
a third data on deviation of a chromaticity point on the CIE chromaticity diagram of the sunlight from the locus of blackbody radiation,
the control unit is configured to extract the first to third data corresponding to place information of any one of the places and time information of any combination of the dates and the times, the place information and time information being inputted to the data input/output unit, from the memory unit, and calculate, based on the first to third data, a mixture intensity ratio of the first to fourth LED modules, and
the electronic circuit is configured to control a value of an electric current which is applied to each of the first to fourth LED modules based on the mixture intensity ratio.