Seiji Yonezawa

TL;DR: In this article, an offset correcting loop for detecting offset component possibly produced due to tilt, deformation and eccentricity of a recording medium or change in optical and mechanical parameters in the course of time lapse is presented.

TL;DR: A magneto-optical data recording system comprises magnetic field applying means for applying a magnetic field pulse of a polarity corresponding to code data to be recorded, and means for heating the recording medium in a pulsating manner at a predetermined frequency synchronous with the code data.

TL;DR: In this article, the shape of holes thermally created by a laser beam in thin films of wide range of materials is studied and the most cleanly shaped holes, which measure up to recent requirements for direct read-after-write video recordings by submicron dots, are obtained in some compositions of amorphous chalcogenide thin films.

TL;DR: In this article, a composite wobbled tracking servo system uses a rotary optical disc which has a header field and a data field alternately arranged along the direction of rotation to provide a sector, and includes pregrooves formed in at least the data field and at least one pair of wobbled track marks disposed in the header field in a relation wobbled relative to the center of a track.

TL;DR: In this article, a composite wobbled tracking servo system uses a rotary optical disc which has a header field and a data field alternately arranged along the direction of rotation, and includes pregrooves formed in at least the data field and at least one pair of wobbled track marks disposed in each of the header fields in a relation wobbled relative to the center of a track.