| 摘要 |
A laminated piezoelectric element and a multi-feed detection sensor not causing degradation of electrical characteristics and an increase in acoustic wave frequency irrespective of a reduction in size are realized. A laminated piezoelectric element (11) includes a piezoelectric element layer (11B) and a matching layer (11A). The piezoelectric element layer (11B) is configured to have a plurality of piezoelectric layers (11B2) and a plurality of electrode layers (11B1) laminated. The matching layer (11A) is laminated on the piezoelectric element layer (11B), and is different in acoustic impedance from the piezoelectric element layer (11B). When Vp represents the acoustic velocity in the piezoelectric element layer (11B), Vm represents the acoustic velocity in the matching layer (11A), Tp represents the thickness dimension of the piezoelectric element layer (11B), and Tm represents the thickness dimension of the matching layer (11A), Vp/Vm=Tp/Tm holds. Further, when W represents the dimension of the laminated piezoelectric element in the width direction, Tp+Tm>W holds. |
