| 摘要 |
PURPOSE:To obtain the complete seal of a discharge lamp and the reliability of electric continuity thereof, by providing a recessed part in the center of a ceramic cap whose conductor is straight and dispersed, and securing the electrode by planting onto the recessed part a pipe-like electrode supporter which is connected to the conductor in order to fix the electrode. CONSTITUTION:Ceramic end cap 2 is so formed that many pieces of bar-like straight conductors 6 are dispersed and sintered there. A conductor 6 is formed into a bar made of tungsten or molybdenum, and such a conductor with its section as small as possible is practically used. Next, a thin wall pipe made of tungsten or molybdenum is formed, in an electrode supporter 7; and an electrode 4 is mounted to the inside of said supporter 7 by welding or the like. A recessed part whose diameter is equal to that of the supporter 7 is provided on the end part of the cap 2, the supporter 7 is fitted to the recessed part and fixed there through contraction of said supporter 7 due to baking in reducing ambient. An electrode terminal 3 is fixed to the conductor part on the under surface of the cap 2 by means of a brazing layer 8. Thus, the stress difference caused by the defference in thermal expansion between the cap and the electrode supporter is absorbed, so that the reliability of electric continuity can be enhanced. |
