Patents by Inventor Doanld L. Siefker

Doanld L. Siefker 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: 4832646
    Abstract: An improved aging process for a cathode ray tube in which the main focusing grid (G3) is aged at a potential below that of the G2 grid, resulting in significantly reduced incidence of dark center cathode.
    Type: Grant
    Filed: January 11, 1988
    Date of Patent: May 23, 1989
    Assignee: North American Philips Consumer Electronics Corp.
    Inventors: Samuel S. Chung, Charles H. Rehkopf, Franklin G. Reigel, Doanld L. Siefker, James R. Stowe