Information recording medium and method of manufacturing resinous substrate for use in the recording medium
US6159572A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 1999 |
| Grant date | Dec 12, 2000 |
| Priority date | — |
| Expiry date | Apr 1, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31678
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam. The distance between the recording surface of the substrate and the light incident surface is smaller than a thickness of the substrate, and a surface roughness "R" of the light incident surface meets a relationship represented by the following formula (1): EQU R.ltoreq..lambda./(8n) (1) wherein .lambda. is a wavelength of the light beam, and n is a refractive index of the first protective film to a light having the wavelength .lambda..
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.