Patents by Inventor Yuhdzi Ishida

Yuhdzi Ishida 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).

  • Patent number: 6069863
    Abstract: An optical pickup includes a diffraction element for causing diffraction in a reflection beam from a disc. This diffraction element is divided into two of first and second regions. On four light receiving elements are converged respectively a first reflection beam from a first region and a second reflection light from a second region. A switch performs switching-over between four output signals individually taken from four light receiving elements and three output signals in total taken out by adding together two output signals of four output signals.
    Type: Grant
    Filed: January 22, 1999
    Date of Patent: May 30, 2000
    Assignee: Rohm Co., Ltd.
    Inventors: Manabu Shimizu, Yuhdzi Ishida, Kenzo Shodo