Patents by Inventor Theodorus A. Koopmanschap

Theodorus A. Koopmanschap 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: 5321676
    Abstract: Scanning apparatus for a disc-shaped record carrier having a spiral track, the apparatus including a scanning head arranged on a slide which is radially displaceable with respect to the record carrier. The scanning point produced by the scanning head is maintained on the track by a tracking control system which includes a fine positioning device secured to the slide and which radially displaces the scanning point within a predetermined limited range of displacement determined by the positioning of the fine-positioning device with respect to the slide. A position-indication signal (PS) indicative of such position is generated, and a control unit detects when such signal exceeds a predetermined limit value. In that event, the control unit energizes a driving motor of the radial displacement device by supplying an energizing pulse pattern thereto which causes displacement of the slide to a position at which the position-indication signal returns to a value below the limit value.
    Type: Grant
    Filed: September 28, 1992
    Date of Patent: June 14, 1994
    Assignee: U.S. Philips Corporation
    Inventors: Johannes L. van Velthoven, Antonius H. M. Akkermans, Theodorus A. Koopmanschap