| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp in which an emitter material can be supplied to the cathode tip with high supply efficiency.SOLUTION: The discharge lamp includes a cathode constituted of a columnar cathode body composed of pure tungsten and having a tip forming the cathode tip, and a rod-like emitter supply member inserted into the cathode body. In the cathode body, an emitter supply member insertion recess opening to the rear end of the cathode body and having a tapered bottom face reducing the diameter in the depth direction, and a through hole elongating from the bottom face of the emitter supply member insertion recess toward the cathode tip are formed. The emitter supply member has a tip where an apical surface, having a surface area larger than the projection area from axially forward, is formed. |
