| 摘要 |
PURPOSE:To obtain a sufficient sound pressure level in a wide range from a low to a high frequency, by linking each one end of plural rectangular piezoelectric bimorphs to a diaphragm, fixing other ends to a frame and driving all the bimorphs in parallel. CONSTITUTION:The plural rectangular piezoelectric bimorphs 10-12 constituted in a same shape are prolonged radially from the center of the frame 13 and each one end is fixed to the frame 13 via a support 14 placed at the center of the frame 13 so as to be vibrated in the form of cuntilever. The diaphragm 15 is fitted to an outer circumferential wall projected to the front face of the outer circumference of the frame 13 via a flexible ring 16 so as to be vibrated freely. The diaphragm 15 is formed with a member made of a ceramic, metal or plastic or the like, the mass is larger than the total mass of the three bimorphs 10-12, and set to a value, e.g., 10 times. |
