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:
Aug. 15, 1989
Filed:
May. 18, 1987
Shingo Kamiya, Hamamatsu, JP;
Yamaha Corporation, Hamamatsu, JP;
Abstract
An optical pickup control device receives a laser beam reflected from a disc pit with a four split photo-detector and performs a tracking servo in response to two diagonal sum outputs of this four split photo-detector. The device comprises a neutral position control circuit which receives a left adjacent sum output and a right adjacent sum output of the four split photo-detector and, in response to these adjacent sum outputs, controls a neutral position of an objective lens so that these adjacent sum outputs become equal to each other. In an embodiment of the invention, the neutral position control circuit servo-controls a feed motor of the optical pickup with a difference signal between the left and right adjacent sum outputs. The device effectively corrects deviation of a beam spot from a center of the four split photo-detector and thereby improves the quality of a tracking error signal.