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. 08, 2012
Filed:
Dec. 13, 2006
Minoru Takazawa, Osaka, JP;
Shin-ichi Yamada, Osaka, JP;
Takeharu Yamamoto, Osaka, JP;
Yasuo Ooishi, Fukuoka, JP;
Minoru Takazawa, Osaka, JP;
Shin-ichi Yamada, Osaka, JP;
Takeharu Yamamoto, Osaka, JP;
Yasuo Ooishi, Fukuoka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
When a focus error signal (FE signal) is detected with an astigmatic method, a track crossing component leaks into the FE signal. Another detection method for the FE signal would reduce the leaking signal, but is not applicable when the light use efficiency decreases. An optical crosstalk correction amount determination unit () determines a correction amount to correct an output of a tracking error detection unit () based on optical crosstalk from a TE signal to an FE signal occurring in reflection light from an optical disc () when a spot crosses a track. An output of the tracking error detection unit () is multiplied by the determined correction amount, and added to an output of the focus error detection unit (). A focus control unit () executes focus control based on the addition result. This effectively reduces a TE signal component that leaks into the FE signal due to optical crosstalk.