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:
Sep. 22, 1998
Filed:
Sep. 23, 1996
Applicant:
Inventors:
Akira Minami, Kawasaki, JP;
Shigeyoshi Tanaka, Kawasaki, JP;
Michio Matsuura, Tokyo, JP;
Hiromichi Kuwano, Yokohama, JP;
Kazuyuki Tamanoi, Hayami-gun, JP;
Assignee:
Fujitsu Limited, Kawasaki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4425 ; 369 4435 ;
Abstract
A positioning control system for performing recording/reproducing operations by irradiating an optical beam on a predetermined position on an optically recording medium includes a photo-detector constituted by at least two-divisional units and a servo-error signal generating circuit which can generate at least one servo-error signal in accordance with a difference between detection currents measured at the collectors of selected transistors in two pairs of transistors.