GLASS FILTER FOR WELDING Russian patent published in 1999 - IPC

FIELD: manufacture of protective shield to control various luminous radiations. SUBSTANCE: optical density of liquid-crystal glass filter for welding rises in process of welding. Filter includes two liquid-crystal cells mounted between polarization filters. During mounting filters are turned and shadow each other. Their relative angular dependencies of optical density compensate one another. Special grooves are made at least in one of cells in mutually inverted forming surfaces of wall to improve this compensation effect. Groove determine direction of orientation of molecules. Relative angular displacement of these directions differs from 90 deg and is less or equal to 85 deg. Predominantly this angle amounts to 20 to 85 deg. EFFECT: improved transmission capacity of filter in clear state, winning of different degree of shadowing for various luminous radiations. 10 cl, 7 dwg