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:
Dec. 24, 1985
Filed:
Oct. 21, 1981
Peter J Janssen, Eindhoven, NL;
Gerard E van Rosmalen, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
An opto-electronic apparatus for inscribing and/or reading recording tracks on a record carrier by means of a radiation beam comprises an objective mounted in an objective holder. The objective holder is supported in a frame by bearing arrangement for movement in accordance with a number of desired degrees of freedom and the apparatus includes electromagnetic actuator means for driving the objective holder in accordance with the desired directions of movement. The bearing arrangement of the objective holder on the frame comprises electromagnetic bearing means for counteracting movements in accordance with at least one undesired degree of freedom. An objective-position measuring device supplies a positional error signal which represents the deviation of the objective holder in accordance with the undesired degree of freedom relative to the frame and which is utilized by a levitation control circuit which counteracts movements of the objective holder relative to the frame in accordance with the undesired degree of freedom by means of electromagnetic levitation forces.