Fujitsu Corporation

Mitsubishi Electric Corporation

Nippon Telegraph and Telephone Corporation

Kazuki Kudo

Tetsuo Takahashi

Shigenori Yanagi

Hidenori Fujii

Kikuji Katoh

A semiconductor device according to the present disclosure is an RC-IGBT in which an IGBT regionand a diode regionare provided adjacent to each other. The diode regionincludes a p-type anode layerprovided on a first principal surface side of an n-type drift layer, a p-type contact layerprovided on the first principal surface side of the p-type anode layerand at a surface layer of a semiconductor substrate on the first principal surface side and connected with an emitter electrode, and an n-type cathode layerprovided at a surface layer of the semiconductor substrate on a second principal surface side. The p-type contact layercontains aluminum as p-type impurities, and the thickness of the p-type contact layeris smaller than the thickness of an n-type source layerprovided in the IGBT region

Semiconductor device

A seek control system is used for a magneto-optic disk unit which has an optical head driven by a VCM positioner, two lens actuators disposed on the optical head, and respective object lenses disposed on the lens actuators for passing first and second beams (erase and write beams) to irradiate an identical track on a medium thereby to record and reproduce data thereto and therefrom. To shorten an access time needed for accessing a target track through a lens seek operation carried out by driving the two lens actuators and to prevent a deviation (off-track) of the second beam from the target track during the VCM positioner seek operation according to the first beam and shorten an access time, upon receiving a seek instruction from a higher device respective, exclusive use processors carry out the lens seek control of the first and second beams, in parallel. The number of tracks respectively crossed the first and second beams are counted so that, when the moving speed of the second beam decreases to a lens seek possible speed at a specified target track due to the positioner seek operation with the first beam, the lens seek operation with the second beam is started.

Seek control system of dual processor magneto-optic disk unit

Growing community of inventors

Tokyo, Japan

Kazuki Kudo