LIGHT SOURCE

摘要

A light source which can extend a life of its discharge tube by reducing the amounts of substances which are produced by the sputter, etc. of electrodes, provided in the vessel of the discharge tube, and which adhere to its light emission window. A heat radiation element is brought into contact with the circumferential region (101ws) of the light emission window (101ww) of the side-on type discharge tube (110) of the light source. The heat radiation element comprises a spring member (101sp) in direct contact with the circumferential region, and heat radiation blocks (101bl), with which the spring member is connected to a heat radiation box (101bx). As the substances produced by the sputter, etc. of the electrodes in the discharge tube adhere mainly to the circumferential region, the substances adhering to the light emission window are reduced, so that the life of the discharge tube can be extended. In the light source, the heat radiation element may be in contact with a head-on type discharge tube and light may be emitted from a protruding part.