Patents by Inventor Takao Edamura

Takao Edamura 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).

  • Base plate for magnetic recording disc
    Patent number: 4430387
    Abstract: A base plate for magnetic recording disc is produced by coating thin metal layers containing no impurities for forming defects by an anodizing treatment on one or both sides of a discoid substrate made of a metal such as aluminum or an aluminum alloy or from a plastic by a dry process, and anodizing the thin metal layers so as to form anodized film from the surfaces of the thin metal layers to a certain depth while the portions contacting to the substrate are retained not anodized.
    Type: Grant
    Filed: November 12, 1980
    Date of Patent: February 7, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Nobuo Nakagawa, Yoshiki Kato, Katsuo Abe, Takao Edamura, Takao Nakamura