High pressure discharge lamp

摘要

A high pressure discharge lamp having a hermetically sealed portion on opposite sides of an arc tube made of quartz glass and in which a pair of opposed electrodes is located is improved so that electrode rod warping is prevented even when the lamp is repeatedly lit and unlit. Electrode rods extending from the electrodes pass through a center hole in a respective quartz glass body which is positioned and fastened onto each the electrode rods with an infrared reflection membrane composed of a heat-resistant metal being provided on the inner surface of the center hole of the quartz glass body separating the electrode rod from the quartz glass body. The quartz glass body is integrated with the quartz glass forming the hermetically sealed portion and is positioned against a step formed at the boundary between large and small diameter portions of the electrode rod.