Toshiba Materials Co., Ltd.

Kabushiki Kaisha Toshiba

Seoul Semiconductor Co., Ltd.

Ryoji Tsuda

Hiroyasu Kondo

Yasuhiro Shirakawa

Masahiko Yamakawa

Tatsunori Itoga

Hiroshi Ohno

Naotoshi Matsuda

Mitsuaki Kato

Yoshitaka Funayama

Katsumi Hisano

Yasumasa Ooya

Atsuji Nakagawa

Toshitaka Fujii

Tomohiko Inoue

Tatsuo Saishu

Kazuki Taira

Noriaki Yagi

Kyung Hee Ye

Masami Okamura

Hiromichi Hayashihara

Kumpei Kobayashi

Shigeki Uno

Kohei Suzuki

Junji Taniguchi

Kiyoshi Inoue

Masahiko Yamakwa

According to one embodiment, a white light source includes a combination of a light emitting diode and phosphors. One of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor. There is no light emission spectrum peak at which a ratio of a largest maximum value to a minimum value is greater than 1.9. The largest maximum value is largest among at least one maximum value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source. The minimum value is adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum.

White light source including LED and phosphors

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

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.

White light source system

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.

Light emitting device and LED light bulb

According to one embodiment, a lighting device includes a hollow globe having an opening at an end thereof, a light source housed in the globe and including at least an LED, a pillar portion housed in the globe and supporting the light source, a cap connector directly connected to the pillar portion, or indirectly connected to the pillar portion via another member, and a cap attached to the cap connector and electrically connected to the light source. A thermally conductive layer is provided between the inner surface of the globe and the lateral surface of the pillar portion.

Lighting device

A lighting apparatus according to an embodiment includes a globe, an optical element including a scattering portion inside and transparent to visible light, and a light source disposed to be opposed to a light incident surface of the optical element. The scattering portion is disposed inside the globe.

Lighting apparatus

Light-emitting diode lamp

A color shutter, comprising first, second and third polarizers, first and second retarders, first and second polarizing rotators, and at least one absorption type partial polarizer. The color shutter is constructed such that the first retarder is arranged between the first polarizer and the second polarizer, that the second retarder is arranged between the second polarizer and the third polarizer, that the first polarizing rotator is arranged between the first polarizer and the second polarizer, that the second polarizing rotator is arranged between the second polarizer and the third polarizer, at least one of the first polarizing rotator and the second polarizing rotator is arranged in a manner to be sandwiched between the second polarizer and the first or second retarder, that the absorption type partial polarizer is arranged between the first polarizing rotator and the first retarder and/or between the second polarizing rotator and the second retarder, and that the transmitted light can be changed into the three primary colors of RGB by selecting the voltage applied to the first and second polarizing rotators.

Color shutter and color image display apparatus

Growing community of inventors

Fujisawa, Japan

Ryoji Tsuda