High pressure mercury ultraviolet lamp

摘要

A high pressure mercury ultraviolet lamp with high dimensional accuracy in which the emitter material during lamp operation is prevented from spraying and being deposited on the wall of the discharge vessel and the UV radiation transmission factor is prevented from being reduced is achieved by the fact that at least one of a group of halides which consists of halides of yttrium, lanthanum, cerium, dysprosium, gadolinium and thorium and at least one of a group of halides which consists of halides of alkali metal elements are filled at a filling ratio in the range from 1:4 to 1:20 to one another as a molar fraction. This also yields the same action as the application of emitter material to the upholding parts of the electrodes. Furthermore, high dimensional accuracy can be ensured by the measure by which the discharge vessel is made of a translucent ceramic, such as YAG.