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. 05, 2012
Filed:
Aug. 26, 2009
Hidenori Wada, Kyoto, JP;
Yoshiaki Komma, Osaka, JP;
Takeshi Shimamoto, Osaka, JP;
Panasonic Corporation, Osaka, JP;
Abstract
An optical disc device is provided with an optical head including a light source, a condensing optical system including an objective lens for receiving a light beam emitted from the light source and forming a microspot on a multilayer optical recording medium, a photodetector for receiving the light beam reflected by the multilayer optical recording medium and outputting an electrical signal corresponding to the amount of light and a coma aberration correcting element for correcting a coma aberration of the condensing optical system, and a processing circuit for controlling the condensing optical system and the coma aberration correcting element. The processing circuit controls the condensing optical system and the coma aberration correcting element so that the correction of the coma aberration from a value suitable for a first recording layer to a value specified for a second recording layer is started before a movement of a focus position of the microspot from the first recording layer to the second recording layer is completed.