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:
Jun. 29, 1999
Filed:
Jun. 06, 1997
Shinichi Ohta, Tokyo, JP;
Moritoshi Miyamoto, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Different tracks on an optical information recording medium are irradiated with first and second light spots for auto-tracking. The light of the first light spot via the recording medium is detected to produce a first detection signal and light of the second light spot via the recording medium is also detected to produce a second detection signal. On the basis of a difference between the first and second detection signals, a signal used for performing tracking control of a third light spot for recording or reproducing information is generated. When recording or reproduction of information is effected on/from one of a first recording medium having a track pitch P.sub.1 and a second recording medium having a track pitch P.sub.2 and the first and second recording media satisfy a relation P.sub.1 -P.sub.2 =d (d is the width of the tracking track) while executing auto-tracking control, a relationship of a direction of movement of the third light spot in a track intersecting direction with respect to a polarity of a signal obtained by subtracting the second detection signal from the first detection signal between the first and second recording media is inverted.