The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 08, 1983
Filed:
Jan. 21, 1981
Louis Arquie, Paris, FR;
Michel Thirouard, Paris, FR;
Thomson-CSF, Paris, FR;
Abstract
The track of a videodisk is followed by a reading light beam produced by a device comprising a reading head fixed on a carriage which forms part of the moving system of a videodisk reader-recorder and is capable of radial displacement along the disk. An objective support frame is capable of displacement in a vertical direction with respect to the carriage in order to maintain focusing of the reading beam and of rotational displacement with respect to the carriage about a transverse axis at right angles to the radial and vertical axes in order to maintain the light beam on the track-following path. Flat coils located vertically in a plane parallel to the carriage path and placed within air-gaps of magnetic circuits serve to develop vertical forces which lift the reading head and initiate the vertical and rotational displacements by means of a differential supply circuit.