| 摘要 |
PURPOSE:To reduce the electric input impedance to improve transmission and reception characteristics by sticking a plate material, which has the same acoustic impedance as a piezoelectric ceramic plate, to the surface opposite to an ultrasonic transmitting and receiving surface through an electrode. CONSTITUTION:In a piezoelectric element, electrodes 3 and 3' are formed on both surfaces of a piezoelectric ceramic plate 1, and the thickness oscillation is utilized. A plate material 2 is stuck to the surface opposite to the ultrasonic transmitting and receiving surface of this piezoelectric element through the electrode 3'. The acoustic impedance of the plate material 2 is equalized substantially to that of the ceramic plate 1. |
