A piezoelectric actuator includes: a diaphragm plate; a first electrode provided on or over the diaphragm plate; a piezoelectric substance layer provided on or over the first electrode; and a second electrode provided on or over the piezoelectric substance layer; wherein the piezoelectric substance layer includes a plurality of active portions sandwiched between the first electrode and the second electrode, either one of the first electrode and the second electrode is an individual electrode provided individually for each of the plurality of active portions, the other of the first electrode and the second electrode is a common electrode that is common to the plurality of active portions, and lead-out wiring is multiple-connected to the individual electrode.

A piezoelectric stack, including: a substrate; an electrode film; and a piezoelectric film comprising an alkali niobium oxide of a perovskite structure represented by a composition formula of (K.sub.1-xNa.sub.x)NbO.sub.3 (0<x<1), wherein an average light transmittance through the piezoelectric film in a wavelength region of visible light and near-infrared ray is 65% or more.

A piezoelectric vibration component that includes a piezoelectric vibrator, a substrate, and a conductive adhesive that bonds the piezoelectric vibrator to the substrate. The conductive adhesive contains a silicone-based base resin, a cross-linker, a conductive filler, and an insulating filler. The silicone-based base resin has a weight-average molecular weight of 20,000 to 102,000. The cross-linker has a number-average molecular weight of 1,950 to 4,620. The conductive filler and the insulating filler have a particle size of 10 μm or less.

Provided is a piezoelectric thin film device in which lattice mismatch between a piezoelectric thin film and a lower electrode layer (first electrode layer) is reduced. A piezoelectric thin film device 10 comprises a first electrode layer 6a and a piezoelectric thin film 2 laminated directly on the first electrode layer 6a; the first electrode layer 6a includes an alloy composed of two or more metal elements; the first electrode layer 6a has a face-centered cubic lattice structure; and the piezoelectric thin film 2 has a wurtzite structure.

A piezoelectric device includes a diaphragm, a piezoelectric actuator, and an orientation layer between the diaphragm and the piezoelectric layer. The piezoelectric actuator has a first electrode, a piezoelectric layer, and a second electrode, with the first electrode, a piezoelectric layer, and a second electrode on the diaphragm. The orientation layer is a stack of two or more tiers.

The present invention relates, in general terms, to piezoelectric thin films with an empirical formula (K.sub.1xNa.sub.x).sub.yNbO.sub.3, wherein 0≤x≤1 and 0.64≤y≤0.95. In particular, the piezoelectric thin film comprises at least two adjacent NbO.sub.2 planes in an antiphase boundary, the at least two adjacent NbO.sub.2 planes displaced from each other by about half a lattice length in either the (100), (010) or (100) crystallographic plane. The present invention also relates to methods of fabricating the piezoelectric thin films.

The present invention provides a piezoelectric sensor that has elastic properties in a surface direction thereof, and can smoothly follow stretching of a body to be measured to accurately measure movement of the body to be measured, and detect movement in a surface direction of a surface of the body to be measured on which the piezoelectric sensor is disposed. The piezoelectric sensor of the present invention includes: a piezoelectric sheet including a porous synthetic resin sheet; a signal electrode layer that is layered on a surface of the piezoelectric sheet and contains conductive fine particles and a binder resin having elastic properties; and a ground electrode layer that is layered on another surface of the piezoelectric sheet and contains conductive fine particles and a binder resin having elastic properties.

A piezoelectric device includes a substrate that is flexible and thermally deformable, and a composite piezoelectric body disposed on the substrate. Output in accordance with deformation of the composite piezoelectric body is obtained. The composite piezoelectric body includes a piezoelectric layer containing an organic binder containing piezoelectric particles, a first electrode layer stacked on a first surface side of the piezoelectric layer, and a second electrode stacked on a second surface side of the piezoelectric layer. The substrate is insert molded and integrated with a molded resin body having a curved shape.

An ultrasonic sensor includes a first electrode, a first piezoelectric layer, a substrate, a second electrode, a second piezoelectric layer, and a third electrode. The first electrode and the first piezoelectric layer are stacked on a first surface of the substrate. The second electrode, the second piezoelectric layer, and the third electrode are stacked on a second surface opposite to the first surface of the substrate. The substrate is made of chemically strengthened glass.

An ultrasonic sensor includes a substrate. A first electrode and a first piezoelectric layer are stacked on one side of the substrate. A second electrode and a second piezoelectric layer are stacked on the other side of the substrate. A notch is defined in the first piezoelectric layer. And a conductive film is coated within the notch to couple the first electrode and the first piezoelectric layer.