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:
Oct. 05, 1999
Filed:
Sep. 04, 1997
Minoru Hashimoto, Chiba, JP;
Shinichi Kariya, Chiba, JP;
Sony Corporation, Tokyo, JP;
Abstract
A tracking control apparatus of an optical disc apparatus capable of preventing unstability of the tracking control due to the deviation of balance of a tracking error signal due to a movement of the field of vision of an object lens. A hysteresis tracking error signal is generated by masking a signal of a half cycle of an off-track state of a tracking error signal at the time of a high speed feeding of a sled and the tracking servo control is carried out by using this signal. Namely, with respect to a tracking error signal calculated at a tracking error calculation circuit, a transistor is turned off by an inverted ENABLE signal indicating the state immediately after the high speed feeding of sled, thereby to make the mirror signal valid, the transistor is turned on when this mirror signal is at a high level indicating the detrack state, a hysteresis tracking error signal obtained by reducing the tracking error signal to the ground level is generated, and the tracking servo control is carried out by using this signal. The component of deviation of the tracking error signal due to the movement of the field of vision of the object lens is reduced to a half, therefore the oscillation of the tracking servo control due to an increase of the accumulation of error can be prevented.