High-density optical information recording medium and a substrate and a stamper for the manufacture thereof
US6721265B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 2000 |
| Grant date | Apr 13, 2004 |
| Priority date | — |
| Expiry date | Feb 18, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/24076
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical information recording medium enables accurate tracking servo throughout the recording area including inner and outer peripheral region by way of reducing the differences between the amplitudes of the push-pull signals from those regions. The medium comprises a light transmitting substrate, a tracking groove formed on a surface of the light transmitting substrate, a recording layer formed on the surface of the substrate having the groove, and a reflective layer, formed on the recording layer, for reflecting recording and reproducing laser beams. The width of the groove at the outer peripheral region is made smaller than that at the inner peripheral region. Specifically, the ratio of the width at the outer peripheral region to that at the inner peripheral region is set to be greater than or equal to 0.8.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.