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:
Jan. 06, 2004
Filed:
Feb. 10, 2000
Applicant:
Inventor:
Yasunori Kuwayama, Ikoma, JP;
Assignee:
Funai Electric Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 7/09 ;
U.S. Cl.
CPC ...
G11B 7/09 ;
Abstract
A light-pickup device has a constitution in which a microcomputer executes control for applying offset voltage to a focus error signal by changing over connection of an FE offset circuit when a servo-processor kicks focus drive voltage for acceleration in order to change over information recording layers of an optical disk having two information recording layers on a plane thereof. Then, a signal output level at a zone in which no focus error signal is occurred, does not coincide with focus zero cross. Owing to this constitution, the servo-processor detects focus zero cross point of the focus error signal even in a simple circuit structure.