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. 01, 2010
Filed:
Apr. 25, 2007
Tsukasa Masuda, Kumamoto, JP;
Hiroshi Tsuji, Fukuoka, JP;
Yoshiro Kashiwabara, Fukuoka, JP;
Shingo Sagata, Kumamoto, JP;
Tsukasa Masuda, Kumamoto, JP;
Hiroshi Tsuji, Fukuoka, JP;
Yoshiro Kashiwabara, Fukuoka, JP;
Shingo Sagata, Kumamoto, JP;
Panasonic Corporation, Osaka, JP;
Abstract
The invention provides an optical disk device that has a laser unit including a first objective lens and a second objective lens. A numerical aperture of the first objective lens is different from a numerical aperture of the second objective lens. The optical disk device has a first focus driver that detects a first voltage value indicating the value of a driving voltage to drive the first objective lens when light beams are irradiated onto the surface of an optical disk via the first objective lens and a focus is achieved. The optical disk device has a second focus driver that detects a second voltage value indicating the value of a driving voltage to drive the second objective lens when light beams are irradiated onto the recording surface of said optical disk via the second objective lens and a focus is achieved. The optical disk device has a controller that discriminates the type of an optical disk, based on a difference between the first voltage value and the second voltage value.