Electrode positioning in metal halide lamps.

摘要

A low wattage metal halide discharge lamp includes an evacuated outer envelope, a domed quartz sleeve therein and an arc tube within the domed quartz sleeve with the arc tube having a pair of electrodes press sealed therethrough with each of the electrodes having a coil thereon spaced from the press seal and from the end of the electrode to provide a figure of merit (FM) substantially equal to the product of the distance from the press seal to the coil and the distance from the press seal to the end of the electrode.