DISCHARGE LAMP

摘要

A discharge lamp includes a cathode in a luminous tube, and an emitter, other than thorium, is added to the cathode. The emitter is prevented from being excessively vaporized from the cathode and depleted soon. Smooth lighting is enabled even at start-up. A main body part (31) of the cathode (3) is made from a metallic material having a high melting point and containing no thorium. A front end (32) is made from a metallic material having a high melting point and containing an emitter (excepting thorium). Inside a sealed space (33) formed in the main body part (31) and/or the front end part (32) is received a sintered compact (34) containing an emitter (excepting thorium) that is higher in concentration than the emitter contained in the front end part (32).