Non-Glare Headlight with a Sodium Nitrate Polarizer as a Filter

Abstract

With a view of obtaining a polarization headlight which is sufficiently bright for a free field driving and at the same time is dim to a driver of an oncoming vehicle who views the headlight through an analyser placed in the crossed position to the polarizer over this headlight, a set of polarization headlight system is constructed. It consists of a sealed beam headlamp with a smooth front cover glass, having the same 50 watt filament as the conventional sealed beam one, a cylindrical lens system over a part of the aperture and a sodium nitrate polarization plate. Illuminance of this set satisfies the Japanese Industrial Standard (JIS), which is equivalent to the SAE in America. Its maximum light intensity, 26200 Cd, is about 2.7 times as high as that of the known type of polarization headlight (9800 Cd) with the use of “Dichrom” or “Polaroid”, and is about 86 per cent of 30600 Cd of the conventional sealed beam headlight.