| 摘要 |
PURPOSE:To aim at stabilizing electron discharge rate and the longevity of electrode by providing a protective dielectric layer at the thin part of the periphery of the dielectric layer formed on a metal conductor in order not to lower the insulating pressure of the part. CONSTITUTION:A discharge container 1 of a transmittant material, a fluorescent body 2, discharge gas 3, a secondary electron discharge material 4 and a dielectric layer 6 formed at a metal conductor 7 for smoothing electron discharge are provided. A protective dielectric layer 5 formed on the layer 6 for strengthening the periphery thinner than the other parts of the dielectric layer 6 and a metal conductor 7 are further provided. In this case, as the electric field is centralized on the electrode peripheral part, if the breakdown is generated in the peripheral part of the dielectric layer, the metal conductor 7 is directly subjected to the ion shock and sputter etched so as to lose original secondary electron discharge function. However, after forming the dielectric layer 6, the peripheral part of the dielectric body is coated with the dielectric body for reinforcing the thin part of the dielectric peripheral part so as to form a protective dielectric layer 5. The longevity of the electrode as well as the stable secondary electron discharge characteristic can be thus obtained. |
