| 摘要 |
PURPOSE:To form a thin and high-efficiency electroacoustic apparatus by driving one diaphragm by free ends of plural piezo-electric bimorphs different in resonance frequency from one another. CONSTITUTION:Plural vibration pieces 3-1- different in length from one another are formed on disc-shaped diaphragm 3, and one ends of vibration pieces are fixed, and free ends are placed near the center of diaphragm 3. Piezo-electric elements 4-1- are fitted to vibration pieces respectively to form plural piezo-electric bimorphs. This diaphragm 3 is fixed to frame 5, and diaphragm 6 which has the circumference fixed to frame 5 is supported by free ends of respective piezo-electric bimorphs. Thus, diaphragm 6 can be driven with efficiency equal to the maximum output in each resonance point throughout the wide frequency region including respective resonance frequencies f1- of piezo-electric bimorphs and can be thin. |
