| 摘要 |
PURPOSE:To prevent an emitter from being broken and dropped and to improve the life and function of an electrode by forming the surface of the emitter into a concave shape using a press-in rod whose tip is spherical or conical before the emitter is fitted in a metal pot and heat-treated. CONSTITUTION:An emitter 5 is fitted in a metal pot 4. A press-in rod 7 whose tip is spherical or conical is inserted in the pot 4 and pressurized. The surface of the emitter 5 is worked into a concave shape. Then when quick heat-treatment such as high frequency heating, etc. is performed, it is so constituted that generated cracks 8 converge to the center of the concave surface since the surface of the emitter 5 is concaved. Therefore, the emitter piece 10 of the emitter 5 is tapered and upward slipping is prevented. As a result, since a part of the emitter 5 is prevented from being broken, the life and function of an electrode can be improved. |
