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. 20, 2003
Filed:
Jul. 14, 1999
Kouichi Takamine, Hyogo, JP;
Shin-ichi Yamada, Osaka, JP;
Takashi Ishida, Kyoto, JP;
Atsushi Nakamura, Osaka, JP;
Seiji Nishiwaki, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical disk includes tracks and grooves, the grooves being formed with a pitch equal to or greater than about &lgr;/NA. A first array of pits is provided at a position which is shifted by a predetermined amount with respect to each track in one of two directions substantially perpendicular to the tracks, the first array of pits being formed with a predetermined pitch, where the predetermined pitch is a function of a pitch of the grooves taking a value within a range from about 0 to about &lgr;/NA. A second array of pits is provided at a position which is shifted by a predetermined amount with respect to the track in the other one of the two directions substantially perpendicular to the tracks, the second array of pits being formed with a predetermined pitch, where the predetermined pitch is a function of the pitch of the grooves taking a value within the range from about 0 to about &lgr;/NA. &lgr; is a wavelength of a light beam which is radiated on the optical disk, and NA to a numerical aperture of a lens.