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:
May. 07, 1991
Filed:
May. 18, 1989
Gohji Uchikoshi, Higashimurayama, JP;
Nakamichi Corporation, Kodaira, JP;
Abstract
A tracking control method in which at least an objective lens within an optical pick-up is so controlled as to be driven in a radius direction of an optical disk having grooves (in a direction traversing track of the optical disk) relative to detectors of two-divided detector means for detecting reflected light quantities of reflected beam obtained by irradiating laser convergent beam of spot diameter defined by .lambda./NA on the optical disk in a manner in which a detection range is divided in the radius direction by estimating a difference information between the detected reflected light quantities, a range of the reflected beam irradiating the detectors being so set that the detectors detect the reflected light quantity equal to each other at a track-on state of irradiation point even though the objective lens moves in the radius direction.