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:
Feb. 14, 1989
Filed:
Dec. 15, 1986
Applicant:
Inventor:
Nobutaka Ohnuki, Tokyo, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 44 ; 369 46 ; 250202 ;
Abstract
In reproducing recorded information from a track on an optical disc by the use of a light beam, a tracking servo is employed for enabling the light beam to follow up the track. When there occurs any tracking deviation due to some flaw or the like on the track, the tracking servo is switched off if the number of times of such tracking deviation has exceeded a predetermined value within a preset time, and simultaenously a braking action is executed to impede the movement of the light beam. The braking force is adjustable in accordance with the velocity of the light beam movement.