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. 04, 1992
Filed:
Aug. 06, 1990
Applicant:
Inventor:
Masanori Doi, Oume, JP;
Assignee:
Olympus Optical Co., Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 4425 ;
Abstract
Disclosed is an optical disk apparatus in which light which returns from a recording medium is led to an photodetector composed of a plurality of light-receiving elements, and focusing is controlled on the basis of an focus error signal which corresponds to the relative distance between an objective and the recording medium. Whether the focusing pull has been conducted normally or not is determined by comparing a standard added signal level which is set by a focus search to the level of an added signal generated after the focusing pull has been conducted.