| 摘要 |
PURPOSE:To prevent a surface discharge caused by minute projections formed at the corner parts of electrodes provided around a discharge tube and avoid breakdown of the discharge tube by applying semiconductor material to the corner part of the electrodes. CONSTITUTION:Semiconductor material 14a-14h is applied and made to adhere to minute projections such as 'flashes' or 'turning-backs' formed in a manufacturing process of a pair of electrodes 2a and 2b which are provided outside a discharge tube 1 facing its circumference surface. With this method, even if a voltage applied between the electrodes 2a and 2b is increased, electric fields at the boundary parts between the discharge tube 1 and the electrodes 2a and 2b are significantly relieved so that a surface discharge is prevented. The shape of the cross section of the discharge tube 1 is not necessarily circular. Also, the electrodes 2a and 2b are a pair of facing electrodes between which a voltage is applied to generate a discharge and may be of spiral type or linear flat plate type. |
