摘要 |
PURPOSE:To reduce the power consumption and facilitate the assembly process by depositing and forming a control electrode on the surface of an envelope. CONSTITUTION:A translucent control electrode 16 is deposited and formed on the inner surface of a front glass 12. When a positive potential against a filament cathode 15 is applied to the anode of a phosphor anode section 14 and also a positive potential equal to or slightly higher than that of the filament electrode 15 is applied to the control electrode 16, thermal electrons emitted from the filament electrode 15 are accelerated and projected to a phosphor layer deposited on the anode, and stimulate and allow it to luminesce for lighting. Furthermore, when a slightly negative potential against the filament cathode 15 is applied to the anode or a negative potential against the filament cathode 15 is applied to the control electrode 16, emission of thermal electrons from the cathode 15 is suppressed to turn off the light. A grid current is rarely flowing through the control electrode 16 during the lighting, thus the power consumption is remarkably reduced. |