| 摘要 |
PURPOSE:To aim at the prevention of conduction between a cathode and an outer supporting member by means of cathode sputtering, by installing a deep spot facing around the conductive continuity lead of an insulated plastic body. CONSTITUTION:An insulated plastic body 20 supports a couple of conductive continuity leads 22 securing a cathode 21 to the upper end by welding and likewise is provided with a spot facing 23 of below 8phimm. in diameter and above 0.7mm. in width by way of example, around the paired conductive continuity leads 22 on the upper part of the insulated plastic body 20. With this, even if there is cathode sputtering out of the cathode 21, no sputtering is produced on the whole surface inside the spot facing 23 at all, so that cnduction between the cathode 21 and an outer supporting member 24 can be well prevented. |
