High-pressure metal halide lamp having three part electrode rods

摘要

A high-pressure metal halide discharge lamp has opposed tungsten electrodes carried by electrode rods. These rods have a first portion of tungsten adjacent the electrodes and a second portion made of at least 25% by weight of rhenium. Their common boundaries are at a location having an operating temperature in the range of 1900-2100° K. The gas filling contains metal oxyhalide and is devoid of rare earth metal compounds.