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: A case member of an ultrasonic sensor includes an outer case member having a substantially cylindrical shape with a bottom surface and an inner case member. Cutout portions having a predetermined size are arranged so as to face each other in a lower portion of a sidewall of the inner case member. The inner case member is made of a metal material having a density that is greater than that of the outer case member. Consequently, an elliptical vibrating-surface amplitude profile can be formed in a vibrating surface of the ultrasonic sensor, and an ultrasonic sensor having stable anisotropy in directional properties can be provided. Further, the ultrasonic sensor has a small amount of displacement of side vibration.

Abstract: A case member of an ultrasonic sensor includes an outer case member having a substantially cylindrical shape with a bottom surface and an inner case member. Cutout portions having a predetermined size are arranged so as to face each other in a lower portion of a sidewall of the inner case member. The inner case member is made of a metal material having a density that is greater than that of the outer case member. Consequently, an elliptical vibrating-surface amplitude profile can be formed in a vibrating surface of the ultrasonic sensor, and an ultrasonic sensor having stable anisotropy in directional properties can be provided. Further, the ultrasonic sensor has a small amount of displacement of side vibration.

Abstract: An ultrasonic sensor includes an integral housing including a plurality of tubular containers that are open at one end and closed by bottom portions at the other end and have side portions extending from the one end to the other end, and at least one connecting portion that connects the plurality of tubular containers. Piezoelectric devices are disposed on respective inner bottom surfaces of the respective bottom portions of the plurality of tubular containers. Side portions of the tubular containers are connected to each other, through a connecting portion, at portions adjacent to bottom portions where the amount of displacement caused by the vibrations of piezoelectric devices is smallest.

Abstract: In an ultrasonic sensor having a case that is integrally constructed from tubular bodies, one end of each of which is open and the other end is closed by the bottom, and from a connection section for connecting the tubular bodies, and having piezoelectric elements individually provided on the inner bottom surfaces of the tubular bodies, reverberation caused by vibration of one of the piezoelectric element may affect the other piezoelectric element through the connection section. Tubular bodies (11, 12) having the bottoms are connected through a connection section (13) to portions of side surface sections (11b, 12b) near bottom sections (11c, 12c), the portions being portions at which displacement by vibration of piezoelectric elements (51a, 51b) is minimum.

Abstract: An ultrasonic vibration apparatus includes a casing having a vibration face, a piezoelectric element mounted in the casing, and a disk-like vibration plate supported at a position along a concentric circle differentiating two regions, an inner region and an outer region. In the ultrasonic vibration apparatus, the disk-like vibration plate is constructed so as to be a part of the casing serving as the vibration face, and, the piezoelectric element is mounted in the central part of the disk-like vibration plate, thereby causing the inner region and the outer region to vibrate in substantially the same phase.

Abstract: An ultrasonic wave transmitter/receiver is provided in which the transmission/reception range thereof in at least one direction is relatively narrow, and which has stable reverberation characteristics. When the thickness of a thick-walled portion is t1, the thickness of each of thin-walled portions is t2, the thickness of a side portion provided continuously with the thin-walled portion is A, x=t2/t1, and y=A/t2, this ultrasonic wave transmitter/receiver is formed so that x and y are within the range defined by the following equations: 0.50≦x≦0.64 0.75y≦1.

Abstract: An ultrasonic wave transmitter/receiver is provided in which the transmission/reception range thereof in at least one direction is relatively narrow, and which has stable reverberation characteristics.

Abstract: An ultrasonic sensor includes a case member and a piezoelectric element. The case member has a hollow therein and a bottom portion provided at one end of the hollow. The bottom portion has a thick portion which extends along a first direction and a pair of thin portions which have a smaller thickness than the thick portion and are provided on opposite sides of the bottom portion along a second direction. The piezoelectric element radiates and/or detects ultrasonic energy and is provided at a center of the thick portion on an inner surface of the bottom portion.