| 摘要 |
PURPOSE:To keep off any variations in breakdown voltage, by installing a light emitting tube whose both ends have the anode and the cathode and sealed inside with a metal halide and mercury, while letting the anode take a core and a coil rolled on this core. CONSTITUTION:A light emitting tube consists of quartz glass or the like, and the cathode 2 and the anode 3 at both ends of the tube are connected to each of external conductors 8 and 9 via metal foil sheets 6 and 7 composed of molybdenum foil or the like sealed up in sealing parts 4 and 5. The cathode 2 consists of a tungsten wire, while the anode 3 is provided with a core 10 composed of the tungsten wire and a coil 11 composed of the tungsten wire being rolled on its one end in two layers. Inside the light emitting tube 1, a metal halide composed of, for example, scandium iodide and sodium iodide, mercury and argon gas of tens torr are sealed. Thus, such the structural anode as having rolled the coil on the core is used whereby an anode surface area grows large and a rise in breakdown voltage is restrainable. |
