| 摘要 |
PURPOSE:To realize the reproducing in a wide band area with making even sound pressure frequency characteristic over the whole area of an audio frequency by area-dividing the electrode of a piezoelectric speaker and driving a diaphragm with inputting a signal having a specified frequency component that is filtered at a filter circuit to each divided electrode area. CONSTITUTION:A diaphragm 11 consists of a sheet of piezoelectric element 12 and an electrode 13 attached on the upper surface of the piezoelectric element 12, and the electrode 13 is area-divided to two area, a large and a small ones, 13a and 13b. And with outputting an amplified signal from an amplifier 14, the signal of all frequency band area that is not filtered is inputted to the small area 13b of the electrode 13, on the other hand, to the large area 13a, only the signal of low frequency component that is filtered at a filter circuit 15 is inputted. Thereby, the area driven with a low frequency is relatively increased and the balance between the low area and the high area of emitting sound pressure is maintained. |
