| 摘要 |
USE OF SILVER TO CONTROL IODINE LEVEL IN ELECTRODELESS HIGH INTENSITY DISCHARGE LAMPS Silver is added to the fill of an electrodeless high intensity metal halide discharge lamp, which includes at least one metal iodide as a fill ingredient, for controlling the iodine vapor level therein. In operation, silver reacts with free iodine, forming silver iodide (AgI), which has a relatively high boiling point and a relatively low vapor pressure. The iodine level is thus controlled below an arc instability threshold to promote and maintain arc stability. In addition, silver does not attack the quartz arc tube wall because silica (SiO2) is much more stable than silver oxide (Ag2O). Moreover, the addition of silver to the arc tube does not accelerate the decomposition of iodides in the fill, such as sodium iodide (NaI), cerium iodide (CeI3), lanthanum iodide (LaI3), neodymium iodide (NdI3), and praeseodymium iodide (PrI3), which would otherwise enhance devitrification and etching of the quartz wall. Lamp performance and life are thus substantially improved using silver as an iodine getter.
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