Patents by Inventor Bob Hoekstra

Bob Hoekstra 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).

  • Videodisc focusing and tracking servo
    Patent number: 4773055
    Abstract: An electro-optical apparatus comprising an objective (7) scans an optical disc (3) having a transparent protective layer (5) by means of a radiation beam (10) which, through the transparent layer, is focussed on a reflecting recording surface (4). The objective moves along the optical axis (19) for focussing the radiation beam on the recording layer and moreover performs limited pivotal movements. The position of the optical axis of the objective is corrected for obliquity of the surface of the optical disc, correction means (22A, B) being provided to tilt the objective through a correction angle, so that the angle between the optical axis and the normal to the disc surface is reduced.
    Type: Grant
    Filed: November 6, 1987
    Date of Patent: September 20, 1988
    Assignee: U.S. Philips Corporation
    Inventors: Wilhelmus A. H. Gijzen, Wilhelm J. Kleuters, Bob Hoekstra, Gerard E. Van Rosmalen