| 摘要 |
<p>PURPOSE:To improve reliability of the welding part between a lead wire and a pin and reduce the dispersion of cut-off voltage by supportedly connecting a heat-resistant insulating substrate to a cathode pin and a lead wire L-shapedly folded to a heater pin. CONSTITUTION:A heat-resistant insulating substrate 1 is supportedly connected by means of cathode pins 7, plantedly erected on a cathode vessel 6, and lead wires 9 L-shapedly folded to heater pins 8. Here the lead wires 9 are welded to the heater terminals 53 and the cathode terminals 31 on the substrate 1. The application of voltage to a heating body 51 causes the heating body 51 to be heat-generated by Joule heat, the substrate 1 to be heated, and the heating of substrate metal 2 to high temperature causes barium oxide, which is a component of an electron radiation substance 4 layer, and the substrate metal 2 to make reaction to conduct electron radiation with Ba, produced by the reaction, as a donor. This high temperature action causes a lead wire 6 to rise to high temperature to make thermal expansion, but because the lead wire 6 is displaced to a dotted line shown condition, the stress to the welding point of the heater pin 8 or the cathode pin 7 is relaxed. This permits reliability improvement of the welding part and reduction of the dispersion of cut-off voltage.</p> |
