Electrically-conductive, contrast-selectable, contrast-improving filter
US5521765A · kind A · utility
89Cited by
9References
27Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 7, 1994 |
| Grant date | May 28, 1996 |
| Priority date | — |
| Expiry date | Jul 7, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B1/14
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention comprises a contrast-improving filter which uses a tri-layer comprising a metal layer, preferably silver, sandwiched between two metal precoat layers. The silver layer is thin so that it is substantially transparent to visible light. Additionally, the contrast-improving filter uses a silicon nitride layer between the tri-layer and further oxide layer to improve the durability and scratch-resistance of the contrast-improving filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.