Laminated piezoelectric element and multi-feed detection sensor

A laminated piezoelectric element comprising:

• a piezoelectric element layer having a plurality of piezoelectric layers and a plurality of electrode layers laminated in a thickness direction;
• and
• a matching layer laminated on the piezoelectric element layer in the thickness direction, the matching layer being different in acoustic impedance from the piezoelectric element layer,
• wherein, when Vp represents the acoustic velocity in the piezoelectric element layer, Vm represents the acoustic velocity in the matching layer, Tp represents the dimension of the piezoelectric element layer in the thickness direction, and Tm represents the dimension of the matching layer in the thickness direction, Vp/Vm=Tp/Tm, and
• wherein, when W represents the dimension of the laminated piezoelectric element in a width direction perpendicular to the thickness direction, Tp+Tm>W.