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:
May. 31, 2011
Filed:
Nov. 16, 2007
Masayoshi Nakamura, Osaka, JP;
Akihiko Nishioka, Osaka, JP;
Yasuo Nakata, Osaka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
A tracking apparatus for an optical information reproduction apparatus includes the following: a photoelectric detector () in which a far-field pattern of a light spot converged on a recording medium is formed across a divided light-receiving cell; an arithmetic unit () for outputting at least a pair of arithmetic signals from the output of the photoelectric detector (); a phase comparator () for detecting a phase difference between the output signals of the arithmetic unit (); an absolute value detector () for detecting an absolute value of the output signal of the phase comparator (); a level detector () for generating a signal that indicates whether or not a convergence position of the light spot is located off an information track by detecting a predetermined number of times or more the output signal of the absolute value detector () has become larger than a predetermined value; a sensitivity detector () for detecting and outputting the sensitivity of the level detector () by observing the output signal of the level detector (); and a controller () for adjusting the detection conditions of the level detector () so that the output of the sensitivity detector () is a predetermined value.