| 摘要 |
PURPOSE:To obtain a satisfactory SN ratio by forming a unit by using a highmolecular piezo-electric film which is wound in the spiral state to increase the electrostatic capacity. CONSTITUTION:A highmolecular piezo-electric film, which is formed into the belt-like long one, is wound in the spiral state. Lead wires 4 and 4 come out from both sides of the highmolecular piezo-electric film 1, and they are connected to electrodes 5 and 5. A base plate 2 is connected to the one side of the highmolecular piezo-electric film, and a diaphragm 3 is connected to the other side of the film. Then, a unit is formed. Such a formation makes it possible to increase the static capacity by increasing the number of windings of the highmolecular piezoelectric film. Therefore, the impedance can be decreased and a satisfactory SN ratio can be obtained. |
