| 摘要 |
PURPOSE:To prevent any spark from being generated between an acceleration electrode and a bulb neck part by attaching a high resistance film inside the bulb neck. CONSTITUTION:Cathode 2, a cup-shaped G1 electrode 3 acting as a control electrode, a cup-shaped G2 electrode 4 acting as an acceleration electrode, a cup- shaped G3 electrode 5 acting as a focussing electrode, a G4 electrode 6 acting as anode are sealed inside of the neck part 1a of a glass bulb 1. The cup-shaped G2 electrode 4 is provided with a ring-shaped flange part 7 having the external diameter more than about 1.4 times of that of its cup-shaped part while cathode 2 is insulatedly supported inside the G1 electrode 3 by a ring-shaped insulating supporter. A thin film 13 with high resistance attached in a region facing to the G2 electrode 4 seals its stem part 1b to the neck part 1a after inserting an electron gun into the bulb neck part 1a, heats the flange part 7 of the G2 electrode 4 with high frequency for about 30sec-2min during evacuation work to evacuate the inside of the bulb 1 into a vacuum or after the evacuation work, while forming a film 13 with high resistance by vacuum evaporation by means of evaporating a part thereof. |
