| 摘要 |
PURPOSE: To avoid premature darkening by an at least main part of an electrode rod being surrounded by a sleeve, consisting of a high-melting point materiaL in a discharge container and enclosing an end of the discharge container by a plug body. CONSTITUTION: An electrode 11 is formed of an electrode rod, consisting of tungsten and an electrode head formed by a spiral part 13 engaged at a discharge part side end. An electrode rod 12 is tightly enclosed by a ceramic sleeve 17. A second introducing conductor 9b is arranged at a second end 6b, and the end 6b is placed as a closed end. The two introducing conductor 9 consist of a niobium tube, and these are deeply inserted into a hole part of the end part plug body. For evacuation and filLing, for example, a filLing part 15 is provided in the vicinity of a pump end 6a, and this charge hole part 15 is sealed by glass soldering or a fused ceramic 15 after filling. Thereby, an electrode tip end is heated quickly, and discharge arcing is started at the tip end of the electrode. |
