Patents by Inventor Charles D. Stelzner

Charles D. Stelzner 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: 4490587
    Abstract: A switch assembly comprising a flexible face cover membrane; a flexible keyboard membrane positioned immediately below the face cover membrane and including a base portion and a plurality of raised hollow contact pad portions projecting upwardly from the base portion through openings in the face cover member; a flexible printed circuit board membrane positioned below the keyboard membrane for switching coaction with the contact pad portions of the keyboard membrane; and adhesive means bonding the membranes together into a thin, flexible sealed switch sandwich. In one embodiment of the invention, the keyboard membrane is formed of a non-conductive elastomeric material and conductive elastomeric buttons are secured to the underside of the contact pad portions of the keyboard membrane for coaction with printed circuitry on the upper surface of the circuit board membrane.
    Type: Grant
    Filed: April 7, 1983
    Date of Patent: December 25, 1984
    Assignee: Microdot Inc.
    Inventors: Paul H. Miller, Charles D. Stelzner