Patents by Inventor Robert L. Whitman

Robert L. Whitman 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).

  • Symmetrical astigmatic focus sensing system
    Patent number: 4025949
    Abstract: An improved focus error correction system for use in an optical playback apparatus features a collimating lens which, in conjunction with a pair of cylinder lenses, form first and second astigmatic (line) images of the reading spot which are monitored by a photodetector to develop an error signal indicative of the sense and extent of defocusing of the reading spot.
    Type: Grant
    Filed: December 31, 1975
    Date of Patent: May 24, 1977
    Assignee: Zenith Radio Corporation
    Inventor: Robert L. Whitman