Patents by Inventor Keiichi Siguyama

Keiichi Siguyama 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: 4988837
    Abstract: The position on a surface of an implement including a tuned circuit with a predetermined resonant frequency is determined and displayed by an apparatus having a housing including the surface. A tablet in the housing includes coils arranged in two coordinate directions parallel to the surface. The coils are excited with AC energy having approximately the same frequency as the resonant frequency. The tuned circuit interacts with the AC energy to change the AC current flowing in the coils as a function of the implement on the tablet. An electronic two-coordinate direction display in the housing configured as a plate is superposed with and lies in a plane parallel to the tablet and the surface. The display responds to the change in AC current resulting from the interaction between the AC energy and the tuned circuit to indicate the position of the implement on the surface.
    Type: Grant
    Filed: April 30, 1990
    Date of Patent: January 29, 1991
    Assignee: Wacom Co., Ltd.
    Inventors: Azuma Murakami, Tsuguya Yamanami, Takahiko Funahashi, Toshiaki Senda, Kazuo Aoki, Keiichi Siguyama, Nobuyuki Miyamori, Akio Kikuchi, Manabu Abe