| 摘要 |
PURPOSE:To form a piezoelectric element protective film having high adhesive properties with a base material without pinhole and to prevent its electric insulation from decreasing under water by coating the base material with a silane coupling agent, drying it, and then coating it with electrically insulating polymer resin by a thermal CVD method. CONSTITUTION:A ceramic cylindrical bass material 1 in which a silver electrode is baked to inner and outer wall faces is cleaned with chlorocene, and dried. Then, leads 4a, 4b are respectively soldered to inner and outer electrodes 2a, 2b, dipped in silicone oil to be polarized, and then left to stand in the silicone oil. Then, it is cleaned with chlorocene, and dried. Thereafter, it is dipped in solution mixed with silane coupling agent. Subsequently, it is dried, coated with electrically insulating polymer resin by a thermal CVD method to form a protective film 3. Eventually, the parts soldered with the leads are reinforced with epoxy resin to complete a piezoelectric element. Thus, an underwater acoustic sensor having high sensitivity and long lifetime can be realized. |
