Short arc-type discharge lamp has anode and cathode between which voltage is applied to generate arc, and concave portion formed on central axis of anode tip surface

摘要

The lamp (10) has anode (3) and cathode (2) between which voltage is applied to generate arc between the anode and cathode. A concave portion is formed on the central axis (L) of anode tip surface. The ratio of diameter of concave portion to the size of arc generated between anode and cathode is within the range of 0.25-1.2.