Patents by Inventor Takeshi Mada

Takeshi Mada has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method and apparatus for beam-track alignment in optical disk apparatus
    Patent number: 4796246
    Abstract: A method of beam-track alignment in an optical disk apparatus comprises detecting the velocity v of a beam spot moving in parallel to the surface of an optical disk and traversing a target track in a direction orthogonal with respect to the track, detecting the displacement x given by the distance between the center of the target track and the present position of the beam spot, and starting tracking control (position control) when the detected values of v and x satisfies a predetermined condition.
    Type: Grant
    Filed: November 20, 1986
    Date of Patent: January 3, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Toshiaki Tsuyoshi, Takeshi Mada