Patents by Inventor William David Schaefer

William David Schaefer 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).

  • Multi-layer solid state keyboard
    Patent number: 7532131
    Abstract: A keypad includes a substrate and one or more layers of decorative material on the substrate. Transparent and/or conventional conductive materials are disposed on the decorative material. Electrical circuit components are soldered to the conductive layers.
    Type: Grant
    Filed: April 22, 2004
    Date of Patent: May 12, 2009
    Inventors: William David Schaefer, David W. Caldwell