ELECTRODE SYSTEM FOR CERAMIC METAL HALIDE LAMP

摘要

A high efficiency and long life electrode system for a ceramic metal halide lamp comprises: a niobium rod or niobium tube (1) sealed within and secured to a ceramic sleeving (9) of a arc tube; a tungsten rod (3) connected with the front end of the niobium rod or niobium tube (1) at its rear end via a electrode feed-through (2), and a tungsten spiral electrode (5) wound on the front end of the tungsten rod (3), the diameter of the tungsten spiral electrode is less than that of the tungsten rod (3), the niobium rod or niobium tube, the electrode feed-through and the tungsten rod are in the same axis, and the electrode feed-through (2) extending in the ceramic sleeving is coated by a high thermal resistant, high temperature resistant material layer (6). The high thermal resistant, high temperature resistant material layer can reduce heat loss of the electrode, increase cool-terminal temperature of the electrode end, help to sufficiently evaporate the metal halide in the tube, reduce the gap between the electrode feed-through and the ceramic sleeving, suppress the metal halide and mercury vapor to enter and reserve in the ceramic sleeving, and improve the stability and life of the metal halide lamp.