Die for use in forming lens
US4882238A · kind A · utility
6Cited by
5References
1Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1988 |
| Grant date | Nov 21, 1989 |
| Priority date | — |
| Expiry date | Oct 3, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03B2215/34
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The present invention relates to a die for use in forming optical lenses made of glass or synthetic resin used in OA instruments, VTR, cameras and the like. In order to lengthen the useful life of the die by suppressing the oxidation or deterioration of the die surface due to temperature and atmosphere and reaction of materials of which lenses are made, when lenses are formed, the die is coated with a single-layer or multi-layer thin film of Si.sub.3 N.sub.4 or SiC or compounds thereof, which are superior in wear and corrosion resistance at high temperatures, by the vapor coating method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.