Abstract: A laminated piezoelectric element that includes a piezoelectric element layer and a matching layer. The piezoelectric element layer is configured to have a plurality of piezoelectric layers and a plurality of electrode layers laminated together. The matching layer is laminated on the piezoelectric element layer, and is different in acoustic impedance from the piezoelectric element layer. When Vp represents the acoustic velocity in the piezoelectric element layer, Vm represents the acoustic velocity in the matching layer, Tp represents the thickness dimension of the piezoelectric element layer, and Tm represents the thickness dimension of the matching layer, Vp/Vm=Tp/Tm holds. Further, when W represents the dimension of the laminated piezoelectric element in the width direction, Tp+Tm>W holds.

Abstract: A laminated piezoelectric element that includes a piezoelectric element layer and a matching layer. The piezoelectric element layer is configured to have a plurality of piezoelectric layers and a plurality of electrode layers laminated together. The matching layer is laminated on the piezoelectric element layer, and is different in acoustic impedance from the piezoelectric element layer. When Vp represents the acoustic velocity in the piezoelectric element layer, Vm represents the acoustic velocity in the matching layer, Tp represents the thickness dimension of the piezoelectric element layer, and Tm represents the thickness dimension of the matching layer, Vp/Vm=Tp/Tm holds. Further, when W represents the dimension of the laminated piezoelectric element in the width direction, Tp+Tm>W holds.

Abstract: An ultrasonic transducer includes a case, a reflective portion, and a piezoelectric body. The case has a substantially cylindrical shape including one closed end in the center axis direction that defines a top. The piezoelectric body is disposed on the inner surface of the top of the case. The reflective portion is arranged to oppose and be spaced apart from the piezoelectric body. The distance between the piezoelectric body and the reflective portion is greater than the maximum displacement of the piezoelectric body and is substantially an odd number multiple of a ¼ wavelength of sound waves or less than or equal to the ¼ wavelength.

Abstract: An ultrasonic transducer includes a case, a reflective portion, and a piezoelectric body. The case has a substantially cylindrical shape including one closed end in the center axis direction that defines a top. The piezoelectric body is disposed on the inner surface of the top of the case. The reflective portion is arranged to oppose and be spaced apart from the piezoelectric body. The distance between the piezoelectric body and the reflective portion is greater than the maximum displacement of the piezoelectric body and is substantially an odd number multiple of a ¼ wavelength of sound waves or less than or equal to the ¼ wavelength.

Abstract: A piezoelectric device is attached to an inner bottom surface of the outer case having a tubular shape including a bottom, and an inner case is disposed within the outer case. In an ultrasonic vibration acting surface of the inner case that is arranged to face the bottom surface of the outer case, a mass of the inner case is arranged to restrain vibration of the outer case, which is generated by the piezoelectric device. A first cutout is provided in a portion of the ultrasonic vibration acting surface and arranged to face the piezoelectric device so as to flatten an ultrasonic beam generated by vibrations of the piezoelectric device and the outer case. Second cutouts are provided at locations on the ultrasonic vibration acting surface spaced away from the first cutout in a line symmetrical relationship with a long axis of the first cutout defining a symmetrical axis.

Abstract: A piezoelectric device is attached to an inner bottom surface of the outer case having a tubular shape including a bottom, and an inner case is disposed within the outer case. In an ultrasonic vibration acting surface of the inner case that is arranged to face the bottom surface of the outer case, a mass of the inner case is arranged to restrain vibration of the outer case, which is generated by the piezoelectric device. A first cutout is provided in a portion of the ultrasonic vibration acting surface and arranged to face the piezoelectric device so as to flatten an ultrasonic beam generated by vibrations of the piezoelectric device and the outer case. Second cutouts are provided at locations on the ultrasonic vibration acting surface spaced away from the first cutout in a line symmetrical relationship with a long axis of the first cutout defining a symmetrical axis.