HIGH PRESSURE SODIUM VAPOR LAMP HAVING UNSATURATED VAPOR PRESSURE TYPE CHARACTERISTICS

摘要

A high pressure sodium vapor lamp having unsaturated vapor pressure type characteristics with sodium and mercury contained in an arc tube. The sodium is enclosed in an amount sufficient to exhibit unsaturated vapor pressure type characteristics while the mercury is enclosed in an amount MHg calculated by the following formula: $where\; MHg\; :\; the\; amount\; of\; mercury\; enclosed\; (mg)\; D\; :\; the\; internal\; diameter\; of\; the\; arc\; tube\; (cm)\; L\; :\; the\; electrode-to-electrode\; distance\; (cm)\; Volume:\; the\; volume\; of\; the\; arc\; tube\; (cc)\; Vn\; :\; the\; rated\; lamp\; voltage\; (Volt).$