A piezoelectric device includes a first substrate including a first surface on which piezoelectric elements and a common terminal coupled to the piezoelectric elements are placed, a second substrate including a second surface on which a common connecting terminal coupled to a control circuit is placed, a third substrate placed between the first substrate and the second substrate and including a third surface joined to the first surface and a fourth surface facing the second surface, and bonding portions bonding the second substrate and the third substrate by an adhesive, wherein the third substrate includes a first through hole penetrating from the third surface to the fourth surface and a first through electrode provided in the first through hole and coupled to the common terminal, the common connecting terminal is coupled to the first through electrode and electrically coupled to the common terminal via the first through electrode, and the second substrate includes a wall suppressing an outflow of the adhesive on the second surface facing the third substrate.

A piezoelectric actuator 10 includes: a piezoelectric element 11; an external electrode 12 covering partially a first surface 11a of the piezoelectric element 11 in a first direction; a wiring member 14; and a conductive joining member 20 joining the wiring member 14 to the external electrode 12, wherein the conductive joining member 20 has an air gap 70 formed between the external electrode 12 and the wiring member 14 in a region overlapping with the wiring member 14 as viewed in the first direction, and wherein the conductive joining member 20 extends to an edge 21 of the external electrode 12 or extends to the first surface 11a of the piezoelectric element 11 beyond the edge 21 of the external electrode 12.

A PMUT ultrasound transducer includes a number of PMUT transmitting elements in a membrane layer. Behind each PMUT transmitting element is a cavity in the membrane layer. The cavities are partially or completely filled with a damping material to reduce ringing of the PMUT transmitting elements. Suitable damping materials include polymers, e.g., soft epoxies, benzocyclobutene or polyimide that are dispersed into the cavities or a phase changing material such as Parylene that precipitates out of a gas phase as a polymer when cured.

In a piezoelectric device, electrode layers are spaced apart from each other in the direction of the normal thereto. A first piezoelectric layer is interposed between two electrode layers of electrode layers in the direction of the normal. A second piezoelectric layer is provided on an opposite side of the first piezoelectric layer from a base portion. The second piezoelectric layer is interposed between two electrode layers of the electrode layers in the direction of the normal. The half-width of a rocking curve measured by X-ray diffraction for a lattice plane of the first piezoelectric layer substantially parallel to a first main surface is smaller than a half-width for the second piezoelectric layer. The piezoelectric constant of a material defining the first piezoelectric layer is smaller than the piezoelectric constant of a material defining the second piezoelectric layer.

Lattice structure with piezoelectric behavior characterized in that the lattice structure (1) comprises a periodic succession of unitary cells (10), wherein each unitary cell (10) is made of a dielectric material, is bending or torsion dominated and comprises nanometric structural connectors (11) connected to each other through nodes (12) defining a non-centrosymmetric shape having a topological constraint that induces torsion or bending of said structural connectors (11); and wherein the unitary cells (10) are connected to each other at least in series defining a continuous electric potential accumulation path with two opposed ends (2, 3), the unitary cells (10) being arranged within the lattice structure (1) in a non-centrosymmetric disposition accumulating and conducting without cancellation the electric gradient generated on each unitary cell (10) through the lattice structure (1) to said two opposed ends (2, 3).

A vortex-induced vibration wind energy harvesting device, including an array consisting of a plurality of oscillators and a plurality of piezoelectric microelectromechanical systems (MEMSs), is provided. An oscillator is mounted on each of the piezoelectric MEMSs. When any one of the oscillators is oscillated by and resonant with vortex shedding due to an incoming airflow, its vortices in the wake will enhance the oscillation of the downstream oscillators, so that overall oscillation of the oscillators in the array is strengthened. The piezoelectric MEMSs are deformed by the vibration of these oscillators to generate voltage and current to output. In the present invention, the oscillators are arranged closely. When the airflow passes the array, even weak airflow can generate periodic force and cause significant oscillation due to resonance. The MEMS can convert mechanical energy into electrical energy and output it in order to achieve the purpose of wind energy harvesting.

Provided is a piezoelectric ceramics including crystal grains each including: a first region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at an asymmetrical position; and a second region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at a symmetrical position, and that is present inside the first region, wherein a ratio of a cross-sectional area of the second region to a cross-sectional area of the piezoelectric ceramics is 0.1% or less.

Provided is an electronic device in which penetrating wires can be formed easily. The electronic device includes a sealing plate 33 having a first surface 41 to which a pressure chamber-forming plate 29 is connected and a second surface 42 which is on a side opposite from the first surface 41 and on which a drive IC 34 is provided; bump electrodes 40 which are arranged in a nozzle row direction on the first surface 41 of the sealing plate 33 and which output signals to piezoelectric elements 32; individual connection terminals 54 which are arranged in the nozzle row direction on the second surface 42 of the sealing plate 33 and to which the signals are inputted, wherein wires each of which connects one of the bump electrodes 40 to one of the individual connection terminals 54 corresponding to the bump electrode 40 each include a penetrating wire 45 formed inside a through hole 45a penetrating the sealing plate 33 and made of a conductor, the penetrating wires 45 are formed at positions away from the bump electrodes 40 or the individual connection terminals 54 in a direction perpendicular to the nozzle row direction, and each two of the penetrating wires 45 adjacent in the nozzle row direction are arranged at different positions in the direction perpendicular to the nozzle row direction.

A piezoelectric element includes a laminate including first and second piezoelectric layers with respective polarization directions in a thickness direction and an elastic layer provided between the first piezoelectric layer and the second piezoelectric layer, first and second terminal electrodes that are provided on an external surface of the laminate, a first detection electrode provided on a positive polar surface of the first piezoelectric layer, a second detection electrode provided on a negative polar surface of the first piezoelectric layer, a third detection electrode provided on a positive polar surface of the second piezoelectric layer, and a fourth detection electrode provided on a negative polar surface of the second piezoelectric layer. The first detection electrode and the fourth detection electrode are connected to the first terminal electrode. The second detection electrode and the third detection electrode are connected to the second terminal electrode.

A piezoelectric transformer that includes a piezoelectric body having driving portions and a power generating portion, an input electrode, and an output electrode. The driving portions and the power generating portion are arranged in the lengthwise direction of the piezoelectric body. The driving portions are disposed symmetrically relative to a plane that passes through a center of the piezoelectric body in the lengthwise direction and is orthogonal to the lengthwise direction, occupy no less than half of the regions in the piezoelectric body, and are include two or more adjacent polarized regions.