Electron tube having glass-to-metal-to-glass seal

摘要

An electron tube is disclosed in which an envelope glass bulb and a glass stem having an electron gun assembly mounted thereon and accommodated within the bulb are sealed to each other. The sealed interface portion between the bulb and the stem incorporates concentrically with the electron gun assembly a metallic ring member made of an alloy or metal material having a good bonding ability to the glass materials of the bulb and the stem. The sealing is effected by a high frequency heating of the metallic ring member. An ohmic heating may be additionally used.