Short arc type discharge lamp

摘要

A short arc type discharge lamp includes a cathode and an anode arranged inside an arc tube to face each other. The cathode comprises a main body portion made of tungsten and an emitter portion made of thoriated tungsten that is joined at the tip of the main body portion, where a metal oxide other than thorium (Th) is contained in the main body portion of the cathode, and a tungsten carbide layer is formed on the metal oxide.