Optical information recording medium and method of fabricating the same
US5040165A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1989 |
| Grant date | Aug 13, 1991 |
| Priority date | — |
| Expiry date | Mar 2, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/261
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical information recording medium in which pre-pits longer than the diameter of a reproducing radiation spot and pre-pits shorter than the diameter of the reproducing radiation spot coexist, the width W of the pre-pit longer than the diameter of the reproducing radiation spot being formed with a value satisfying a relation of .PHI./4<W<.PHI./3, wherein .PHI. is the diameter of the reproducing radiation spot and a method of fabricating the optical information recording medium comprising setting a power of a radiation beam when a pre-pit shorter than the diameter of the reproducing radiation spot among a plurality of pre-pits to be formed for each sector is cut to a predetermined optimum value, setting a power of the radiation beam when the pre-pit longer than the diameter of the reproducing radiation spot is cut to a predetermined value smaller than the predetermined optimum value of the radiation beam power when the pre-pit shorter than the diameter of the reproducing radiation spot is cut, and performing the cutting of pre-pits while combining the radiation beam power at the predetermined optimum value when the pre-pit shorter than the diameter of the reproducing radiation s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.