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. 29, 2006
Filed:
Apr. 19, 2002
Tsutomu Maruyama, Chiba, JP;
Masami Yuasa, Chiba, JP;
Tsutomu Maruyama, Chiba, JP;
Masami Yuasa, Chiba, JP;
Sony Corporation, Tokyo, JP;
Abstract
After making such adjustment that an a main push-pull signal MPP offset can be made zero when a main beam is positioned at the center of a main photoreceptor, using electric signals E and F photoelectrically converted by one of two two-divided side beam photoreceptors and electric signals H and G photo-electrically converted by the other thereof, a side push-pull signal SPP including a constant α is determined for allowing respective (F−αE) and (αH−G) offsets to be made zero and is calculated according to the formula, SPP−(F−αE)+(αH−G). From this SPP signal and the main push-pull signal MPP, a differential push-pull signal DPP is then calculated, thereby allowing stable tracking control to be carried out, even during recording.