| 摘要 |
PURPOSE:To make easy the design of a small-sized acoustic device without lowering the performance, by using high polymer piezoelectric element for diaphragm plate and giving a function as the diaphragm plate for a microphone, in electromagnetic or drnamic type elector-acoustic converter with sound discharging construction using double diaphragm plates. CONSTITUTION:A magnet 14 which is formed by winding a coil 15 on a magnetic core 16 under a supporting frame 17 of cylindrical type is fitted by turning it upside. A diaphragm plate 12 having a moving iron 13 with a specified size on the upper side is provided by opposing to the magnet 14, a piezoelectric film 9 is covered on it and a speaker frame 18 is provided on the supporting frame 17 including it. With this constitution, as a piezoelectric film 9, a high polymer piezoelectric film having a resonance point at high frequencies is used. When it is used as a microphone, the film is functioned as a diaphragm plate and when it is used as a speaker, it is used as a sound dissipating plate. If the resonance frequency is too low only with the film, plastic or metallic base is sticked to the film. Thus, the elasticity is controlled for the microphone and the inertia is done for the speaker. |
