Toshiba Materials Co., Ltd.

Kabushiki Kaisha Toshiba

Seoul Semiconductor Co., Ltd.

Tsubota Laboratory, Inc.

Masahiko Yamakawa

Yasuhiro Shirakawa

Noriaki Yagi

Kumpei Kobayashi

Yasumasa Ooya

Katsutoshi Nakagawa

Ryoji Tsuda

Tatsunori Itoga

Tsutomu Ishii

Ryo Sakai

Hajime Takeuchi

Hiroyasu Kondo

Atsuji Nakagawa

Kazuo Tsubota

Toshitaka Fujii

Toshihide Kurihara

Tomohiko Inoue

Hidemasa Torii

Naotoshi Matsuda

Kyung Hee Ye

Masami Okamura

Yumi Ito

Hirofumi Takemura

Daichi Usui

Kenji Terashima

Junji Taniguchi

Chiharu Tomura

Natsuko Inada

Kiyoshi Inoue

A light emitting device including a substrate, a first light emitter to emit light having a first color temperature, and a second light emitter to emit light having a second color temperature, in which the first light emitter has a first converter including first phosphors and a first resin, each first phosphor having different half—value widths, the second light emitter has a second converter including second phosphors and a second resin, each second phosphor having different peak wavelengths, at least one phosphor of the first converter has a half-value width of 33 nm to 110 nm, a distance between peak wavelengths of at least two phosphors of the second converter is 150 nm or less, and at least one phosphor of the first converter has a particle size of 5 um to 50 um.

White light source system

A white light source and method of use thereof, wherein control of daily rhythm and pleasant lighting can be realized. Amounts of stimulation light emitted from a white light source to the intrinsically photosensitive retinal ganglion cells (ipRGCs) and visual cells of the L cone and M cone, are defined as a melanopic irradiance, an L-cone opic irradiance, and an M-cone opic irradiance, respectively; a ratio of the amounts of the stimulation light is expressed by formula (1); and A is the ratio corresponding to the emission spectrum of the white light source, and B is the ratio corresponding to the radiation spectrum of a black body having the same color temperature as the white light source, an amount of stimulation light emitted to the ipRGC is quantitatively changed by changing the emission intensity of the white light source satisfying formula (2).Melanopic irradiance/(-cone opic irradiance+-cone opic irradiance)  (1)0.88≤≤1.11  (2).

Method for using white light source, and white light source

A light source for myopia prevention article includes a light emitter to emit light having an emission spectrum continuing from a first wavelength of not less than 360 nm nor more than 400 nm to a second wavelength of more than 400 nm.

Light source for myopia prevention article and method of using light source for myopia prevention article

A light emitting device including a substrate, a first light emitter to emit light having a first color temperature, and a second light emitter to emit light having a second color temperature, in which the first light emitter has a first converter including first phosphors and a first resin, each first phosphor having different half-value widths, the second light emitter has a second converter including second phosphors and a second resin, each second phosphor having different peak wavelengths, at least one phosphor of the first converter has a half-value width of 33 nm to 110 nm, a distance between peak wavelengths of at least two phosphors of the second converter is 150 nm or less, and at least one phosphor of the first converter has a particle size of 5 um to 50 um.

A light emitting device including a substrate, a first light emitter to emit light having a first color temperature, and a second light emitter to emit light having a second color temperature, in which the first light emitter has a first converter including first phosphors and a first resin, each first phosphor having different half-value widths, the second light emitter has a second converter including second phosphors and a second resin, each second phosphor having different peak wavelengths, at least one phosphor of the first converter has a half-value width of 33 nm to 110 nm, a distance between peak wavelengths of at least two phosphors of the second converter is 150 nm or less, at least one phosphor of the first converter has a particle size of 5 um to 50 um, and a thickness of the second converter is in 0.07 mm to 1.5 mm.

According to one embodiment, there is provided a white light source system. P(&#x3bb;), B(&#x3bb;) and V(&#x3bb;) 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: 

According to one embodiment, there is provided a white light source system. P(&#x3bb;), B(&#x3bb;) and V(&#x3bb;) 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:&#x222b;(&#x3bb;)(&#x3bb;)(&#x3bb;)(&#x3bb;)&#x2003;&#x2003;(1)

A phosphor according to an embodiment is a europium-activated alkaline-earth chloroapatite phosphor having a composition expressed by a composition formula: (MEu)(PO)Cl, where M is an alkaline-earth element containing at least Sr and Ba, x is an atomic ratio satisfying 0.04&#x2264;x&#x2264;0.2. In the phosphor of this embodiment, absorptance of light at a wavelength of 400 nm is 90% or more, and absorptance of light at a wavelength of 650 nm is 2% or less.

Europium-activated alkaline-earth chloroapatite phosphor and light-emitting device thereof

According to one embodiment, there is provided a white light source system. P(&#x3bb;), B(&#x3bb;) and V(&#x3bb;) 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:&#x222b;(&#x3bb;)(&#x3bb;)(&#x3bb;)(&#x3bb;)&#x2003;&#x2003;(1)(&#x3bb;)/(&#x3bb;)&#x2264;1.8.&#x2003;&#x2003;(2)

According to one embodiment, there is provided a white light source system including white light sources. An absolute value of a difference between (P(&#x3bb;)&#xd7;V(&#x3bb;))/(P(&#x3bb;max1)&#xd7;V(&#x3bb;max1)) and (B(&#x3bb;)&#xd7;V(&#x3bb;))/(B(&#x3bb;max2)&#xd7;V(&#x3bb;max2)) for each of the white light sources satisfies a relational expression represented by|(((&#x3bb;)&#xd7;(&#x3bb;))/((&#x3bb;max1)&#xd7;(&#x3bb;max1))&#x2212;((&#x3bb;)&#xd7;(&#x3bb;))/((&#x3bb;max2)&#xd7;(&#x3bb;max2))|&#x2264;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.

There is provided a white light source approximating sunlight and being capable of reproducing a subtle difference in sunlight which changes depending on times and locations, and provided a white light source system of a lighting system or the like. The white light source includes a light source unit. Light which is emitted from the light source unit is a chromaticity point on a CIE chromaticity diagram and has a correlated color temperature corresponding to a chromaticity point including a deviation of &#x2212;0.005 or more to +0.005 or less with respect to a black body radiation locus, and satisfies a formula: &#x2212;0.2&#x2264;[(P (&#x3bb;)&#xd7;V (&#x3bb;))/(P (&#x3bb;max1)&#xd7;V (&#x3bb;max1))&#x2212;(B (&#x3bb;)&#xd7;V (&#x3bb;))/(B (&#x3bb;max2)&#xd7;V (&#x3bb;max2))]&#x2264;+0.2.

White light source and white light source system

According to one embodiment, an illumination system includes a plurality of white light sources that satisfies &#x2212;0.2&#x2264;[(P(&#x3bb;)&#xd7;V(&#x3bb;))/(P(&#x3bb; max 1)&#xd7;V(&#x3bb; max 1))&#x2212;(B(&#x3bb;)&#xd7;V(&#x3bb;))/(B(&#x3bb; max 2)&#xd7;V(&#x3bb; max 2))]&#x2264;+0.2 where P(&#x3bb;) is an emission spectrum of a white light source having a specific color temperature, B(&#x3bb;) is an emission spectrum of black body radiation having a corresponding color temperature, V(&#x3bb;) is a spectrum of spectral luminous efficiency, &#x3bb; max 1 is a wavelength at which P(&#x3bb;)&#xd7;V(&#x3bb;) becomes maximum, and &#x3bb; max 2 is a wavelength at which B(&#x3bb;)&#xd7;V(&#x3bb;) becomes maximum. The respective white light sources have different color temperatures, and light from the respective white light sources is irradiated from different directions to a target.

Illumination system for reproducing the color temperature range of solar light for illuminating exhibits

According to one embodiment, there is provided a white light source system. P(&#x3bb;), B(&#x3bb;) and V(&#x3bb;) 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:  where P(&#x3bb;) is a light emission spectrum of white light, B(&#x3bb;) is a light emission spectrum of blackbody radiation of a color temperature correspond to a color temperature of the white light, and V(&#x3bb;) is a spectrum of a spectral luminous efficiency.

A light emitting device includes: a first white light source which includes N pieces of first white light emitting diodes and emits a first white light; and a second white light source which includes M pieces of second white light emitting diodes and a first resistance element electrically connected in series to the second white light emitting diodes and having a first resistance value, is electrically connected in parallel to the first white light source, and emits a second white light, the light emitting device emitting a mixed white light of the first white light and the second white light. The drive voltage of the first white light source is higher than a drive voltage of the second white light source, and a color temperature of the mixed white light is higher as a total luminous flux of the mixed white light is higher.

Growing community of inventors

Yokohama, Japan

Masahiko Yamakawa