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:
Mar. 07, 1995
Filed:
Sep. 13, 1989
Hitachi, Ltd., Tokyo, JP;
Abstract
A light spot positioning method and apparatus for performing a seek operation of positioning a record/playback light spot at a desired track on a recording medium by a macro moving mechanism for an optical head and a micro moving mechanism mounted on the optical head or the base of the apparatus, and for selecting the bandwidth of the control servo of the micro moving mechanism to be higher than 10 KHz during a track pull-in operation. By selecting the bandwidth of control servo of the micro moving mechanism higher than 10 KHz, the track can be pulled in with the relative velocity between the track and the light spot remaining high. During a track following operation after the completion of the track access, the band of the control servo of the micro moving mechanism is changed to a low level of lower than 5 KHz.