Patents by Inventor Frederick J. Kahn

Frederick J. Kahn 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).

  • Liquid crystal cell for image projections and method of operating same
    Patent number: 4799770
    Abstract: A liquid crystal cell for an image projection apparatus has a liquid crystal layer sandwiched between two conductive layers. The layer surface is divided into one or more regions and one of the sandwiching conductive layers is divided into separate sections each matching a different region. Busbars are bonded on the other of these conductive layers along the edges and boundary lines between adjacent regions (resistors) such that negative and positive writing/erasing can be performed in selected region or regions. By applying one or more current pulses in one or more of these resistors, the corresponding region or regions can be more completely erased and a uniform dark background can be created therein.
    Type: Grant
    Filed: March 8, 1988
    Date of Patent: January 24, 1989
    Assignee: Greyhawk Systems, Inc.
    Inventors: Frederick J. Kahn, Elizabeth A. Nevis, Jerry Leff
  • Clean up kit
    Patent number: D394531
    Type: Grant
    Filed: May 29, 1996
    Date of Patent: May 19, 1998
    Assignee: Kraft Paper Sales Company, Inc.
    Inventor: Frederick J. Kahn