In one embodiment, an apparatus includes a resonant structure having a plate, a drive electrode and a sense electrode. The resonant structure defines an axis substantially orthogonal to a plane defined by the plate when the resonant structure is not excited. The plate is formed from a piezoelectric material. The drive electrode is configured to excite the resonant structure, and the sense electrode is configured to sense a signal in response to rotation of the resonant structure about the axis.

A piezoelectric element includes a first electrode layer, a piezoelectric body layer, and a second electrode layer laminated in this order, and a conductive layer that is located from the first electrode layer to the piezoelectric body layer, in which the piezoelectric body layer includes a first portion overlapping the second electrode layer, a second portion overlapping the conductive layer, and a third portion not overlapping the second electrode layer and the conductive layer, in a plan view which is viewed from a laminate direction of the first electrode layer, the piezoelectric body layer, and the second electrode layer, and in which a thickness of at least a part of the third portion is smaller than a thickness of the first portion.

An apparatus is provided for harvesting energy from mechanical vibrations with an improved power output. The apparatus comprises a frame (22), a first member (20) comprising a piezoelectric material, a cantilever beam (26) and an electrode. The first member is fixed to the frame at a first position and a second position and extends between the first and second positions. The cantilever beam has a first end fixed to the first member between the first position and the second position and a second end fixed to a proof mass (24). The electrode is fixed to the first member at a position between the first position and the second position. In another aspect, the apparatus may comprise a plurality of proof masses connected to the first member between the first and second positions in a spaced relationship to one another.

A buzzer unit 4 includes a case 10, a vibrating element 11, and a pressing member 14. The case 10 includes a vibrating plate 28 in which no through-holes are formed. The case 10 includes a storage space 22 formed therein on the lower side X2 of the vibrating plate 28. The vibrating element 11 faces the vibrating plate 28 in the vertical direction X inside the storage space 22, produces vibration as a result of voltage being applied thereto, and as a result, causes the vibrating plate 28 to vibrate. The pressing member 14 is stored in the storage space 22, and presses the vibrating element 11 against the vibrating plate 28.

An ultrasonic transmitter and ultrasonic receiver include a piezoelectric layer and at least one conductive layer comprising metal nanoparticles. The metal nanoparticles may be a silver nanoparticle, copper nanoparticle, gold nanoparticle, palladium nanoparticle, nickel nanoparticle, and the mixture thereof. Use of metal nanoparticles as a conductive layer provides for ultrasonic transmitters or receivers with smooth, dense, and highly conductive electrodes, thus resulting in reduced ultrasonic energy loss and improved image quality.

An ultrasonic device includes a vibration portion, a first electrode, a piezoelectric body, and a second electrode which are laminated in this order in a laminate direction, in which an outer circumferential edge of the first electrode is larger than an outer circumferential edge of the piezoelectric body in a plan view across the laminate direction, in which the piezoelectric body includes an active portion that is provided in the vibration portion, and an extraction portion that is connected to the active portion and is provided over the inside and the outside of the vibration portion, in which a width dimension of the extraction portion is smaller than a width dimension of the active portion, and in which the second electrode is provided on the active portion and the extraction portion.

A piezoelectric thin film is formed by adding a donor element to lead zirconate titanate. In the piezoelectric thin film, a molar ratio of lead to a total sum of zirconium and titanium is 105% or higher, and, when positive and negative coercive electric fields in polarization and electric field hysteresis are referred to as Ec (+) and Ec (?), respectively, a value of |Ec (+)|/|Ec (?)| is 0.5 or more and 1.5 or less.

An elastic wave device includes a piezoelectric substrate, an IDT electrode including a first electrode layer located on the piezoelectric substrate and including one of Mo and W as a main component and a second electrode layer laminated on the first electrode layer and including Cu as a main component, and a dielectric film located on the piezoelectric substrate and covering the IDT electrode. The piezoelectric substrate is made of lithium niobate. The dielectric film is made of silicon oxide. The elastic wave device utilizes Rayleigh waves propagating along the piezoelectric substrate.

A piezoelectric device includes a supporting body, a supporting layer that is stacked on the supporting body, a first electrode that is formed on a side opposite to the supporting body side of the supporting layer, a piezoelectric body that is formed on a side opposite to the supporting layer side of the first electrode, and a second electrode that is formed on a side opposite to the first electrode side of the piezoelectric body, in which the piezoelectric body is formed throughout an area covering the first electrode, the second electrode is formed throughout an area covering the piezoelectric body, and a recess portion which is recessed toward the supporting body is formed outside an area overlapping with the first electrode in the supporting layer.

An ultrasonic probe includes an acoustic lens, which is positioned in an emission direction of the ultrasonic waves emitted by an ultrasonic element and has end face in a direction intersecting the emission direction, and a resin portion which is opposed to acoustic lens end face and which includes a filler and resin in a case where the end face of the acoustic lens is set as the acoustic lens end face.