Medium press. arc discharge lamps - contain mercury and ferrous iodide with less stable metal iodide, increasing UV emission

摘要

Medium press. arc discharge lamps with a quartz tube contg. Hg and metal-halogen, acting as economical source for 250-440 nm UV light, have a filling of Hg, FeI2 and a metal iodide (I) with lower chemical stability than the FeI2. (I) pref. is SbI3, AsI3 or esp. HgI3. Increased UV emission and maintenance of the light output throughout the lifetime of the lamps, the maintanace of the output in the 360 nm region after 1000 h operation being 84%, cf 70% if no HgI2 is added. The filling contains 2-4 mg Hg, 0.05-0.6 mg FeI2 and 0.05-0.6 mg HgI2 per ml discharge tube vol. E.g. a 400 W arc discharge lamps with a vol. of 18 ml was filled with 3.6 mg FeI2. 1.8 mg HgI2 and 45 mg Hg.