Optical information record medium
US5993971A · kind A · utility
0Cited by
1References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 19, 1993 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | May 19, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31507
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
There is disclosed an optical information record medium having an optical information record layer on a transparent substrate, in which the transparent substrate is made of a resin material mainly consisting of a polycarbonate resin that contains no more than 4 wt % of low molecular weight fractions having a weight average measured with respect to a polystyrene molecular weight of no more than 3500, in order to avoid a double refraction of an optical information record medium resulting in an improved signal to noise ratio and having superior thermal-transformation resistance and impact resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.