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:
Apr. 01, 1997
Filed:
Oct. 14, 1994
Daniel Bec, Villaneuve Tolosane, FR;
Jean-Pierre Le Merer, Portet Sur Garonne, FR;
Michele LeBlanc, Fonsorbes, FR;
Art Tech Gigadisc 'ATG', Toulouse, FR;
Abstract
The present invention relates to various improvements to a device for access and tracking to a track carried by an information medium, the information being readable and/or recordable optically by a focused radiation, this track forming, on the medium, regularly-spaced or variably spaced revolutions, the revolutions forming a spiral or having the form of concentric circular elements, the device comprising an optical head (1) with optical axis A orthogonal to the plane of the medium, a fixed magnetic circuit comprising at least one core (7) secant to the set of revolutions of the track, in the gap of which two coils (14, 15) move permitting respectively track access and radial tracking to be achieved, as well as focusing of the radiation onto the track, the optical head and the two coils being fixed rigidly to one another in such a way as to form a single compact mobile unit. According to one improvement, the two coils (14, 15) are set in a symmetric arrangement, the desired movement being obtained by addition of forces (F, F') induced by the currents flowing in the coils.