Kabushiki Kaisha Toshiba

Tadashi Umeji

Masayuki Ishikawa

Koichi Nitta

Satoshi Komoto

Haruhiko Okazaki

Kuniaki Konno

An image display device including a light emission section which emits light to an intensity adjusting section and a wavelength conversion section which change the intensity and wavelength of the emitted light. Phosphors and phosphor like materials are employed in wavelength conversion and a liquid crystal is employed for the light adjustment. The light emission device may include plural semiconductor light emitting elements having a different wavelength ranges such as diodes stacked in a compact and predetermined order such that wavelengths of light from each diode are emitted from the light emitting elements.

Image display device and light emission device

Semiconductor light-emitting device with wavelength change material

A P-type epitaxial silicon layer is formed between an N-type epitaxial layer and a P.sup.+ -type semiconductor substrate. An impurity concentration profile is formed in at least one region of the P-type epitaxial silicon layer to decrease with an increase in distance from the substrate and toward the N-type epitaxial layer. A depletion layer is formed as a function region (P-N junction) between the P-type epitaxial silicon layer and the N-type epitaxial layer. Carriers are generated when light is incident on the depletion layer. Carriers are also generated in a region of the P-type layer deeper than the depletion layer. A self-electric field is formed in the P-type epitaxial silicon layer by the impurity concentration profile, which is lowest at the junction. The carriers generated in this manner are accelerated by the self-electric field and flow rapidly into the function region. As a result, an optical semiconductor device according to the present invention has good response characteristics.

Optical semiconductor device and method of manufacturing the same

Growing community of inventors

Kitakyushu, Japan

Tadashi Umeji