| 摘要 |
PURPOSE:To improve the radiation resistance capacity of an electret condenser microphone (ECM) and to obtain an ECM most suitable for a sound detecting element in a nuclear equipment, etc. by convering a dielectric film constituting an electret diaphragm with a shielding member consisting mainly of lead. CONSTITUTION:Radiant rays irradiated from the circumferential direction of a case 11 to the inside of the case 11 is shielded by a shielding body 12 stuck on the outer face of bottom wall of the case 11 and a lead layer 26 provided on the face a sound pressure introducing hole 13 side of a high molecular film 24. Radiant rays from the opening face side of the case 11 is shielded by a shielding body 36 stuck on a blocking plate 15. Thus, even if radiant rays are irradiated from all directions, direct irradiation of the radiant rays on the high molecular film 24 is prevented by the presence of the shielding bodies 12, 36 and the lead layer 26. |
