| 摘要 |
PURPOSE:To obtain a loudspeaker in which a sensitivity difference is small with a wide frequency band by dividing one surface of a piezoelectric plate into plural areas and preparing the electrode group of a boundary divided in parallel to respective areas. CONSTITUTION:A disk piezoelectric body is divided into seven areas, and the electrode group and divided electrode groups dividingly bound respective disk piezoelectric bodies in parallel to respective divided areas. Namely, the number (n) of the divided electrodes is seven, and respective divided electrodes compose seven circular arc divided electrodes S1, S21, S22, S31, S32, S41 and S42 having larger areas toward a center. Since the boundary between a driving part and a non-driving part is not made into a concentric direction and a diameter direction, a vibration attitude having a node at the boundary is made hard to appear, and a sound pressure peak is also made small. Thus, the digital driving type piezoelectric loudspeaker can be obtained in which the sensitivity difference is small over the wide frequency band. |
