Kabushiki Kaisha Toshiba

Toshiba Materials Co., Ltd.

Kazuaki Otsuka

Naomi Shida

Masaaki Tamatani

Ryosuke Hiramatsu

Hiroki Iwanaga

Akio Amano

Junichi Kinoshita

Kenji Shimomura

Yoshihito Tsutsui

Toshihiro Kuroki

A semiconductor light emitting device includes: a semiconductor light emitting element; a first phosphor which absorbs light emitted from the semiconductor light emitting element and emits first wavelength-converted light; and a second phosphor which absorbs light emitted from the semiconductor light emitting element and emits second wavelength-converted light. The first phosphor has a first excitation spectrum region where excitation intensity increases with increasing wavelength around a peak wavelength of the semiconductor light emitting element. The second phosphor has a second excitation spectrum region where excitation intensity is flat or decreases with respect to increasing wavelength around the peak wavelength of the semiconductor light emitting element.

Semiconductor light emitting device

A semiconductor light-emitting element is disposed in a depression of a container. A first fluorescent material layer is located in the depression. At least a portion of the first fluorescent material layer is provided between the opening of the depression and the semiconductor light-emitting element. A second fluorescent material layer having first and second portions is disposed in the depression. The first portion is provided between the bottom of the depression and the semiconductor light-emitting element. The second portion is provided between the side surface of the depression and the semiconductor light-emitting element. The first and second fluorescent material layers are excited by the light radiated from the semiconductor light-emitting element to emit a light having a first wavelength longer than the emission wavelength of the semiconductor light-emitting element and another light having a second wavelength longer than the first wavelength respectively.

Optical semiconductor device

A lighting device including a supporting member, a light emitting element disposed on the supporting member, and emitting light from an upper and side surfaces thereof, a first fluorescent layer containing an organic phosphor and disposed on the supporting member, and a second fluorescent layer containing only an inorganic phosphor and disposed on the supporting member, wherein the second fluorescent layer is disposed to cover the upper and side surfaces of the light emitting element, and the first fluorescent layer is disposed on at least side surface of the light emitting element with the second fluorescent layer being interposed between the light emitting element and the first fluorescent layer.

Lighting device, image pickup apparatus and portable terminal unit

Disclosed is a fluorescent substance comprising an alkaline earth metal silicate having a composition represented by the following general formula (1):(SrBaCaEu)SiO&#x2003;&#x2003;(1)

Fluorescent substance, method of manufacturing fluorescent substance, and light emitting device using the fluorescent substance

A distributed feedback semiconductor laser comprises a semiconductor substrate, a waveguiding structure, provided on the semiconductor substrate, including a diffraction grating, an active layer and a top layer for ohmic contact, a first electrode provided on the top layer, a second electrode attached to the semiconductor substrate, and means for compensating spatial nonuniformity of a carrier density caused by spatial hole burning. The means changes an electrical resistance between the first electrode and the active layer, corresponding to a spatial distribution of photon density along the waveguiding structure.

Growing community of inventors

Yokosuka, Japan

Kazuaki Otsuka