High-pressure sodium discharge lamp

摘要

A high-pressure sodium discharge lamp provided with a ceramic discharge vessel, in which sodium, mercury and xenon are present, of which the xenon is at a pressure at 300K of at least 26.7 kPa. The sodium and the mercury are present in a weight ratio Na/Hg which is at least 0.075 and at most 0.125. The lamp generates in the operating condition a spectrum, in which at a wavelength of 589.3 nm a self-absorption band is present, which is limited by spectral flanks each flank having a respective maximum. There is a wavelength difference DELTA lambda of at least 3.5 nm and at most 6 nm between the maxima.