| 摘要 |
PURPOSE:To make not to generate eccentricity of a diametral electron beam pass hole with scarce generation of discharge inside a tube by making G2 electrode a complex electrode consisting of a plate electrode and a cylindrical electrode and providing a high-resistance film on the internal periphery of the glass bulb neck part. CONSTITUTION:A cylindrical electrode 13 is held by an insulating support 6 so that its bottom may be adjacent to a plate electrode 14 and coaxial while having a diametrally far larger opening 16 than an electron beam pass hole 15 at the bottom and being connected with the plate electrode 14 through a metal piece. And on the internal peripheral surface of the neck part 8 of a glass bulb 7, an evaporation film 18 of a conductive substance evaporated mainly from the surface part of the cylindrical electrode 13 by high frequency heating of said electrode is widely surrounding near the cylindrical electrode 13. G2 electrode appears to be divided into the cylindrical electrode 13 and the plate electrode 14 so as to cause no practical trouble even when a little plastic deformation is generated on the cylindrical electrode 13 at the time of high frequency heating. Also the generation of discharge inside the tube is checked by the high resistance film 18. |
