| 摘要 |
PURPOSE:To reduce the size, the thickness and the weight by making a piezoelectric board serve as a resilient vibration base body then arranging an electrode split into four sections on the surface of the piezoelectric board while arranging a common electrode on the rear face thereof, thus providing a piezoelectric unit. CONSTITUTION:Electrodes 2-4 split into four sections and polarized with same polarity are arranged on the surface of a thin rectangular piezoelectric board 1 in a piezoelectric unit U1 while a common electrode 6 is arranged on the rear face of the piezoelectric board 1. Two vibrators 7a, 7b projecting integrally from the upper side of the piezoelectric board 1 are formed at the side of vibration when the piezoelectric board 1 bends in the direction Y. Consequently, secondary inherent bending vibration is produced. Since two resonances of length and longitudinal bending can be produced simultaneously when power is fed to each set of electrode, a self-oscillation circuit can be constituted easily. |
