Optical recording medium with high density track pitch and optical disk device for recording and playback of the same
US6882616B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 2001 |
| Grant date | Apr 19, 2005 |
| Priority date | — |
| Expiry date | Jul 30, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/24082
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention provides an optical recording medium and an optical disk device realizing prevention of crosswrite and uniformity of playback signals and capable of easily securing compatibility with a read only disk. It provides an optical recording medium on which light LB condensed by a lens (12, 14) having a numerical aperture of 0.85±0.1 and a wavelength of 405±5 nm is focused for recording or playback, having a substrate 1 formed with a groove 2 in its surface, an optical recording layer 3 formed on the substrate and having topography corresponding to the groove, and a light transmission type protection layer 4 formed on the optical recording layer; used when light for recording or playback is focused from the protection layer side to the optical recording layer; using as a recording area only the optical recording layer of one of a side far from the emitting side of the light for recording or playback, that is, a portion corresponding to a recessed portion of the topography, and a side close to it, that is, a portion corresponding to a projecting portion; having a track pitch of 0.32±0.01 μm; and having a depth D2 of a recessed portion with respect to a projecting port…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.