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:
Dec. 20, 2011
Filed:
Dec. 19, 2007
Masao Fujita, Osaka, JP;
Kenji Tanaka, Osaka, JP;
Shinji Kawakami, Osaka, JP;
Sadamu Kuse, Osaka, JP;
Masao Fujita, Osaka, JP;
Kenji Tanaka, Osaka, JP;
Shinji Kawakami, Osaka, JP;
Sadamu Kuse, Osaka, JP;
Hitachi Maxell, Ltd., Ibaraki-Shi, Osaka, JP;
Abstract
The present invention provides a recording and reproducing apparatus that can perform high-precision tracking servo control by removing noise from detected servo signals. The recording and reproducing apparatus performs tracking servo control while reading servo signalsthat are formed on a surfaceof a recording mediumso as to produce optical contrast, the apparatus including a modulated irradiatorfor irradiating the servo signalswith a light beam, the intensity of the light beam being modulated by a modulating wave that is frequency-modulated; a photoelectric converterfor converting reflected light from the servo signalsinto electric signals; and a synchronous demodulatorfor subjecting the electrical signal to synchronous demodulation using the modulating wave as a reference wave.