Patents by Inventor Sadao Sakamoto

Sadao Sakamoto 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: 4957776
    Abstract: The method of manufacturing an optical disc related to the invention first forms warp prevention layer on one surface or the other surface of the disc substrate where information is recorded on one surface, and then, recording film covering the surface opposite from the surface having warp prevention layer or beam reflection film covering the information-recorded surface, and finally protection layer covering either the beam reflection film or the recording film, in this order. Thus the optical disc related to this invention can prevent damage and dust from incurring and adhering to the other surface of the disc substrate when forming these films on one surface so that the warp prevention layer can be perfectly level by suppressing swell of the layer itself.
    Type: Grant
    Filed: January 3, 1989
    Date of Patent: September 18, 1990
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Masahiro Higuchi, Sadao Sakamoto, Yoshiharu Uchihara