| 摘要 |
PURPOSE:To secure an excellent withstand voltage characteristic without any extra process, by forming a graphite conductive film at a region that opposes more than three electrodes different in the neck inside wall of a valve. CONSTITUTION:In case of an electron gun structure in which first-fourth electrodes 21-24 and a cathode 30 are held by means of a bead glass 40, each of graphite conductive films of 10-500mum in thickness, 0.5-10cm in width, by way of example, is formed on a neck inside wall opposite to the second electrode 22- the third electrode 23. With this, a withstand voltage characteristic can be improved while working efficiency can be improved as well. |
