High-pressure metal vapor discharge lamp, and method of its manufacture

Abstract

A high-pressure metal vapor discharge lamp, for example and specifically a etal halide vapor discharge lamp, has a discharge vessel, in which electrodes are fitted from both ends, in form of an elongated ceramic hollow body, in which, in accordance with the invention, the ceramic is translucent, high-purity aluminum nitride (AIN). The end portions are closed off by closing electrodes in form of either solid pins or rods, from which electrode elements carried on shafts (13) extend, or a hollow tube (19) fitted into the end portion of the aluminum nitride discharge vessel and pinched and soldered shut. The solid or tubular closing elements can be inserted into a pre-sintered discharge vessel, preferably under inert atmospheric conditions, in a meticulously clean environment. For translucidness, the high-purity aluminum nitride should have less than 0.05% of metal cations, which may cause coloring or discoloration, less than 0.01% iron as two or three valent ions, and less than 0.01% of silicon or tungsten carbide (all percentages by weight), but may contain dopings between 0.01% and 5% of oxides or fluorides of the metals yttrium, calcium, neodymium, lanthenum and/or aluminum.