| 摘要 |
PURPOSE:To obtain an effective acoustic pressure, by fixing the center part of a piezoelectric speaker diaphragm to oscillate the peripheral part and suppressing the resonance phenomenon. CONSTITUTION:The center of a diaphragm 1 is fixed to the tip of a pole 5 fixed to the center of a frame 4. A thin film 10 having a large internal oscillation loss is stuck to the diaphragm 1, and the outside edge part is stuck to the frame 4. The peripheral part of the diaphragm 1 is held freely oscillatably on the frame 4 through a wave-shaped part 11 formed between the diaphragm sticking part and the frame sticking part of the thin film 10. In the piezoelectric speaker having this constitution, when a signal source 8 outputs an AC or pulsating current, the diaphragm 1 causes the flexural oscillation, but the peripheral part is oscillated because the center part is fixed. Further, since the peripheral part of the diaphragm is connected to the frame 4 by the thin film 10, the resonance to the natural oscillation of the diaphragm 1 is suppressed, and an effective acoustic pressure is obtained. |
