| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an impregnated type cathode capable of being stable operation even at the time of high output operation of an arc lamp and its manufacturing device as well the arc lamp. SOLUTION: A porous tungsten is machined in a truncated cone shape to form a cathode peripheral part 12 of a cathode body, and a cathode central part 11 is inserted in a centered hole under pressure. Into the outside a compound containing BaO, CaO, Al2 O3 in the mol ratio of 6:1:2 as material of easily emitting electrons is impregnated after they are heated and melted at the temp. of 1700 deg.C. Then, the outside of the part 12 is covered with a metal layer having a high melting point made of a tungsten sheet, and the lower part is welded and fixed, thereby forming an impregnated type cathode 15. When the cathode 15 performs arc discharge operation a barium oxide impregnated as the material of easily emitting electrons into the part 12 is melted out to move to the tip of the part 11 for allowing arc discharge operation.</p> |
