| 摘要 |
PURPOSE:To improve a workability as well as a characteristic by forming a projecting part in the outer periphery of one principal plane side on a piezoelectric plate, providing a groove to one direction reaching from other principal plane side to the projecting part in the direction of a thickness, and disconnecting the center part of the piezoelectric plate. CONSTITUTION:A common electrode 11 is formed on the whole surface of a recessed face, and plural concentric circular electrodes 12a-12c are formed on a projecting face. And plural dividing grooves 13 are arranged side by side to be disconnected except the outer peripheral part, an epoxy resin is filled so as to reach the outer-most concentric circular electrode 12c, and the disconnected concentric circular electrodes 12a-12c are reconnected with a copper foil and the like. As mentioned above, since the concentric circular electrodes 12a-12c are formed on one piezoelectric plate 10, a positioning becomes easy, the outer periphery of common electrodes 11a-11c of one principal plane side are not disconnected by the dividing groove 13 but connected electrically, an opposite area between each vibrating part where the concentric circular electrodes 12a-12c are formed becomes smaller, and a leakage due to an acoustic connection is reduced. Thus, the workability as well as an ultrasonic character are improved. |
