High-pressure sodium-vapor discharge lamp

摘要

The invention relates to a high-pressure sodium-vapor discharge lamp having substantially the same color temperature as an incandescent lamp. The invention provides a high-pressure sodium-vapor discharge lamp having a low re-ignition voltage. This is achieved by including xenon and mercury in the discharge tube such that (i) the weight of mercury is between 50% and 90% of the combined weight of the mercury and sodium, (ii) the pressure of the xenon at room temperature is between 100 and 1000 torr, and (iii) the sodium vapor pressure is between 300 and 800 torr in the operating condition of the lamp. The power consumed by such a lamp is typically one-fifth of that consumed by an incandescent lamp having the same light output.