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. 13, 2001
Filed:
Jun. 22, 1998
Toshimitsu Kaku, Sagamihara, JP;
Toru Kawashima, Fujisawa, JP;
Takehiko Sekine, Chigasaki, JP;
Hisataka Sugiyama, Kodaira, JP;
Yosiho Suzuki, Fujisawa, JP;
Tetsuya Fushimi, Chigasaki, JP;
Other;
Abstract
A beam is irradiated to an information recording medium having land tracks and groove tracks alternately formed on a track formed in turn on an information recording surface thereof and pre-pits so pre-formatted as to deviate from the center of the track, a return beam of the irradiated beam is received by detectors split into two parts in a track direction to obtain a differential signal, the pre-pit is detected from this differential signal and control of recording and reproducing processings is executed by using the pre-pit detection signal so obtained as the reference.