| 摘要 |
PURPOSE:To obtain sufficient sound pressure level ranging from a low to a high frequency by driving stably a diaphragm at both ends being free ends of plural square bar piezoelectric bimorphs supported at the center so as to produce an audible tone. CONSTITUTION:The center of plural square bar piezoelectric bimorphs 11-13 is fitted and fixed to support stands 14-16 fitted to a frame 10 so as to make both ends vibrate freely at the state of center support. On the other hand, the circumference section of the flat diaphragm 17 is fixed to a circumferential section of the frame 10 via a corrugation 18, and both ends being free vibrating ends of the bimorphs 11-13 are connected respectively to the diaphragm 17 by a connecting piece 19. Thus, the flat frequency characteristic having the high sound pressure level over a broad range from a low to a high frequency is obtained. |
