# US 10,375,786 B2 · White light source system

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- Number: US 10,375,786 B2
- Document ID: US10375786B2
- Status: Granted
- Kind: B2
- Application number: 16/251,468
- Filed: 2019-01-18
- Published: 2019-05-23
- Granted: 2019-08-06
- Earliest claimed: 2015-06-24
- Assignees: Kabushiki Kaisha Toshiba; Toshiba Materials Co., Ltd.
- Applicants: Kabushiki Kaisha Toshiba; Toshiba Materials Co., Ltd.
- Inventors: Masahiko Yamakawa; Noriaki Yagi; Kumpei Kobayashi
- Web page: https://patentgrep.com/patent/US10375786B2

## CPC

- H10W 90/00: Package configurations
- F21S 2/00: Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
- H05B 45/20: Controlling the colour of the light
- H05B 47/10: Controlling the light source
- H05B 47/16: by timing means
- H10H 20/80: Constructional details
- H10H 20/851: Wavelength conversion means
- H10H 20/8513: {having two or more wavelength conversion materials}
- H10H 20/8515: {not being in contact with the bodies}
- H10H 20/853: characterised by their shape
- H10H 20/854: characterised by their material, e.g. epoxy or silicone resins
- H10H 29/24: comprising multiple light-emitting semiconductor devices
- F21W 2131/405: for shop-windows or displays
- F21Y 2113/13: comprising an assembly of point-like light sources
- F21Y 2115/10: Light-emitting diodes [LED]
- Y02B 20/00: Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B 20/40: Control techniques providing energy savings, e.g. smart controller or presence detection
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- F21S: NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- F21W: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
- F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

According to one embodiment, there is provided a white light source system. P(λ), B(λ) and V(λ) satisfy an equation (1) below in a wavelength range of 380 nm to 780 nm. The white light source system satisfies an expression (2) below in a wavelength range of 400 nm to 495 nm: ∫ 380 780 ⁢ P ⁡ ( λ ) ⁢ V ⁡ ( λ ) ⁢ d ⁢ ⁢ λ = ∫ 380 780 ⁢ B ⁡ ( λ ) ⁢ V ⁡ ( λ ) ⁢ d ⁢ ⁢ λ ( 1 ) P ⁡ ( λ ) / B ⁡ ( λ ) ≦ 1.8 . ( 2 ) where P(λ) is a light emission spectrum of white light, 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.

## Claims

### Claim 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:
∫
380
780
⁢
P
⁡
(
λ
)
⁢
V
⁡
(
λ
)
⁢
d
⁢
⁢
λ
=
∫
380
780
⁢
B
⁡
(
λ
)
⁢
V
⁡
(
λ
)
⁢
d
⁢
⁢
λ
(
1
)
P
⁡
(
λ
)
/
B
⁡
(
λ
)
≦
1.8
.
(
2
)
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 R1 to R8 and special color rendering indexes R9 to R15 are 90 or more.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 3)

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.

### Claim 5 (depends on 4)

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.

### Claim 6 (depends on 5)

The white light source of claim 5, wherein a blue-green phosphor is further contained in the mixture of phosphors.

### Claim 7 (depends on 4)

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.

### Claim 8 (depends on 4)

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.

### Claim 9 (depends on 1)

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

### Claim 10 (depends on 9)

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.

### Claim 11 (depends on 10)

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.

### Claim 12 (depends on 9)

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.