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:
Dec. 11, 2007
Filed:
Apr. 16, 2003
Yoshitsugu Araki, Tsurugashima, JP;
Mitsuru Sato, Tsurugashima, JP;
Yoshitsugu Araki, Tsurugashima, JP;
Mitsuru Sato, Tsurugashima, JP;
Pioneer Corporation, Tokyo-to, JP;
Abstract
The depth of pits is determined by a trade-off between the level of a push-pull signal used for servo application by a push-pull method and the level of an RF signal as a reproduced signal of information. The depth d is set to be the optimum for a disk system, which has a refractive index n of a medium, an optical wavelength λ, and an optical system with a NA (Numerical Aperture) of 0.75. The most suitable depth d for both the push-pull signal level and the RF signal level falls within a range of λ/5.5n≦d≦λ/4.7n, the second most suitable depth d falls with a range of λ/5.5n≦d≦λ/4.5n, and the depth d as the widest standard falls within a range of λ/8n≦d≦λ/4.5n.