| 摘要 |
PURPOSE:To enable to reproduce low band, by making the center coincident with a diaphragm where a plurality of small holes are formed on the external circumference and sticking a flat shape piezoelectric element. CONSTITUTION:A flat shpae piezoelectric element 21 and a flat shape diaphragm 22 are sticked by coinciding the mutual centers. A plurality of round holes 23, 23... are made at the external circumference of the diaphragm 21 at a prescribed distance from the center. The stiffness of the diaphragm 21 is lowered by the round holes 23, 23... provided at the external circumference of the diaphragm 21, resulting that the resonance frequency is decreased and a large amplitude can be obtained. |
