High density optical recording medium and method for reproducing thereof
US7190664B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 3, 2001 |
| Grant date | Mar 13, 2007 |
| Priority date | — |
| Expiry date | May 12, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/261
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical disc includes an information recording layer having a record of information as a pit train with a predetermined track pitch and a light-transmissive layer formed on the information recording layer so that the information can be reproduced by a beam of light illuminated through the light-transmissive layer to the information recording layer by an objective lens. The optical disc includes a feature in that a relationship of 0.194(λ/NA)2≦TP ×Tmin≦0.264(λ/NA)2 is satisfied, provided that the track pitch is TP, a pit shortest length is Tmin, a wavelength of the light beam is λ and a numerical aperture of the objective lens is NA. The optical disc also includes a feature in that a pit width is 120 nm or smaller in a range of a track pitch of 0.280 to 0.325 μm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.