DISCHARGE LAMP HAVING A CATHODE WITH CARBON SOLID-SOLVED IN A TUNGSTEN METAL SUBSTRATE OF THE CATHODE

摘要

A discharge lamp having a cathode containing lanthanum oxide (La2O3) as an electron emission material, to provide a discharge lamp where reduction of lanthanum oxide (La2O3) is accelerated; a supply amount of lanthanum (La); and its lifespan is long has an anode (4) and a cathode (5) arranged within a discharge vessel (1) so as to face toward each other in a tube axis direction of the discharge vessel (1), and the cathode (5) is made from a material containing a metal oxide of lanthanum (La2O3) and a metal oxide of zirconium (ZrO2) in a tungsten metal (W) substrate with carbon present as a solid solution in the tungsten metal (W) substrate forming the cathode (5).