IMAGE TUBE

PURPOSE:To prevent generation of internal electric discharge and destruction of photoelectric face caused thereby by setting the thickness of a ring-shaped metal film, which is to make electrical connection between the photoelectrical face provided on the photoelectric base plate and the external electrode, to a value within a certain specified range. CONSTITUTION:A photoelectric face processing bulb 30 is made by airtightly fixing a photoelectric base plate 2 of transparent glass onto a metal electrode 1 subjected to a preliminary oxidation previously by the use of a high frequency heating device. After fixing, oxide film on the surface of this metal electrode 1 shall be removed. Then the boundary zone of the metal electrode 1 of the photoelectric face processing bulb 30 to the photoelectric base plate 2 shall be covered with a ring-shaped aluminum film 3. This ring-shaped aluminum film 3 has a thickness between 0.5 and 10mum and connects the photoelectric face of image tube to the metal electrode 1 electrically.