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:
Jul. 17, 2001
Filed:
Oct. 06, 1998
Josephus A. H. M. Kahlman, Eindhoven, NL;
Gerard E. Van Rosmalen, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
An optical disk drive for reading and/or writing information from/on an optical disk includes an auxiliary lens to compensate for optical aberrations and a servo loop for positioning the auxiliary lens relative to a main lens. The servo loop includes an actuator for driving the auxiliary lens and a controller to feed the actuator coil with a drive current dependent on a position signal which is derived from the actual inductance of the actuator coil and a reference signal which indicates a desired position of the scan element. The disk drive also includes an inductance influencing device to vary the inductance of the actuator coil as a function of the position of the scan element.