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:
Nov. 02, 2004
Filed:
Sep. 27, 2001
Toshihiro Sugaya, Tokyo, JP;
Yoshinori Honguh, Tokyo, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
An optical disk with sectional trapezoidal pits comprising a substrate having information recorded by a plurality of pit trains formed thereon at a specified track pitch, and a reflective layer formed on the substrate, wherein the information is reproduced by being irradiated with light beam via an objective lens, the track pitch is set within the range of (0.72 to 0.8) &agr;×&lgr;/NA/1.14 &mgr;m when a wavelength of the light beam is &mgr; nm and a numerical aperture of the objective lens is NA, each of the pits is a multiplication ratio used to secure allowable disk tilt angles in an upper width within the range of (0.3 to 0.50) &agr;×&lgr;/NA/1.14 &mgr;m, a bottom width within the range of (0.2 to 0.32) &agr;×&lgr;/NA/1.14 &mgr;m and a depth within the range of (1/4.2×&lgr;/n) to (1/5.2 &lgr;/n) (n: refractive index of said substrate and &lgr;: a wavelength) and obtained by 2.623×10 ×(d/&lgr;) −1.706×10 (d /&lgr;)+0.934, where d is thickness of the substrate.