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. 04, 2013
Filed:
Oct. 01, 2009
Kazuyo Umezawa, Yokohama, JP;
Seiji Morita, Yokohama, JP;
Masatoshi Sakurai, Tokyo, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
According to one embodiment, this invention determines whether a maximum value Hmax and minimum value Hmin of an HF signal obtained when a data recording portion is irradiated with a laser having a wavelength of 450 nm or less and an NA of 0.6 or more meet (Hmax−Hmin)/Hmax<0.13 . . . (1), or whether a maximum value Hmax, a minimum value Hmin, and a most frequent voltage value Have of a signal level of an HF signal obtained when a data recording portion is irradiated with a laser having a wavelength of 450 nm or less and an NA of 0.6 or more meet Hmax/Have≦1.05 . . . (2) and Hmin/Have≦0.90 . . . (3).