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:
Jan. 28, 1992
Filed:
Oct. 13, 1987
Shigeyoshi Tanaka, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A position control system for an information storage system, for example, an optical disc system, includes a stepping motor for moving a read-write head and a DC motor for moving a beam reflecting unit, such as an object lens mounted on the head. The position control system drives the stepping motor to compensate a positional error of the beam reflecting unit in a tracking mode after a seek without disturbing the movement of the beam reflecting unit. The position control system includes a master control unit operatively connected to a host controller, a stepping motor control unit, and a track servo control unit. The master control unit activates the stepping motor control unit for a seek operation upon receipt of a seek command from the host controller. The stepping motor control unit drives the stepping motor with a large drive current until the head moved by the stepping motor reaches a position adjacent to a target track on the recording medium. In a tracking operation, the track servo control unit drives the DC motor in response to a positional error of the head at the target track to finely control a position of the head at the target track. The stepping motor control unit drives the stepping motor by a predetermined rotation angle with a small drive circuit to compensate a position of the access end when the position of the beam reflecting unit exceeds a limit of a controllable range of the beam reflecting unit.