Xenon metal halide lamp having improved thermal gradient characteristics for longer lamp life

摘要

A high brightness discharge light source having improved thermal balance characteristics includes a lamp envelope having an arc chamber formed therein and a pair of electrodes extending into opposite ends of the arc chamber so as to be displaced from one another by a distance of no greater than 4 mm. A fill disposed within the arc chamber is excited to a discharge state upon the introduction of an excitation energy coupled through the pair of electrodes. The light source is operated vertically so that one of the electrodes is disposed at the top region and the other electrode is disposed at the bottom region of the arc chamber. The arc chamber is formed having a diameter dimension which is just larger than the spacing between the electrodes, and a height dimension which is approximately twice the diameter dimension. The diameter dimension is substantially uniform along the length of the arc chamber. The uniform diameter characteristic is effective so that the thermal operating properties associated with the discharge state are substantially equally distributed from the top to the bottom regions of the arc chamber thereby resulting in extending the life of this light source to approximately 6000 hours.