Optical filter for protective welding lens assemblies
US4728173A · kind A · utility
85Cited by
12References
6Claims
0Family size
Inventor
Key dates
| Filing date | Feb 22, 1985 |
| Grant date | Mar 1, 1988 |
| Priority date | — |
| Expiry date | Feb 22, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/13475
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
An optical filter for welding protective lens assemblies has two parallel electro-optical cells, at least one of the cells being of the nematic type with admixture of dye molecules with anisotropic light absorption. The filter comprises a filter sheet disposed in the ray path of the cells and allowing transmission within a wave range which is offset with respect to the wave range within which said one cell is transmitting residual light in its absorbing state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.