An acoustic wave device includes a support substrate, a piezoelectric layer provided on the support substrate, at least a pair of comb-shaped electrodes provided on the piezoelectric layer, each of the comb-shaped electrodes including a plurality of electrode fingers, and an insulating layer provided between the support substrate and the piezoelectric layer, the insulating layer having, in at least a part thereof, a plurality of void regions of which extending directions are different from each other when viewed from a thickness direction of the support substrate, a width in the corresponding extending direction of each of the void regions being longer than a width in a direction orthogonal to the corresponding extending direction when viewed from the thickness direction of the support substrate.

A bonded body includes a supporting substrate, a silicon oxide layer provided on the supporting substrate, and a piezoelectric material substrate provided on the silicon oxide layer and composed of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate. An average value of a nitrogen concentration of the silicon oxide layer is higher than a nitrogen concentration at an interface between the silicon oxide layer and supporting substrate and higher than a nitrogen concentration at an interface between the silicon oxide layer and piezoelectric material substrate.

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 actuator array includes a substrate plate with a number of signal leads and at least one common lead, and a number of piezoelectric bodies arranged in a row on one surface of the substrate plate and formed by dividing a common piezoelectric block. The piezoelectric bodies include a number of active bodies each of which has, on a first side of the row, a signal electrode in contact with one of the signal leads and, on an opposite second side of the row, a common electrode in contact with the common lead. The substrate plate has at least one connector lead disposed on the first side of the row and electrically connected to the common lead on the second side of the row. At least one piezoelectric body has a conductive outer surface layer that establishes an electrically conductive path from the connector lead to the common lead.

A method is provided for fabricating a thin-film electronic device employing a piezoelectric plate. The method provides a plurality of piezoelectric plates, and a substrate with electronic devices, each electronic device including a top surface well. A piezoelectric plate suspension is formed and flowed over the substrate. In response to the piezoelectric plate suspension flow, piezoelectric plates are captured in the top surface wells. The electric device top surface wells have well bottom surfaces, with bottom electrical contacts formed on the bottom surfaces. Thus, the capture of a piezoelectric plate in a top surface well entails interfacing a piezoelectric plate electrode, either the first electrode or the second electrode, to the bottom electrical contact. Subsequent to capturing the piezoelectric plates in the top surface wells, a thin-film process forms a conductive line overlying the exposed piezoelectric device electrode (i.e., the electrode not connected to the bottom electrical contact).

A sensor includes a substrate having a curved surface, a piezoelectric element, and an adhesive disposed between the piezoelectric element and the curved surface along a vertical direction. The adhesive attaches the piezoelectric element to the substrate. The adhesive has an exterior bond surface that has a tapered shape along the vertical direction from the piezoelectric element to the curved surface.

A sensor includes a substrate having a curved surface, a piezoelectric element, and an adhesive disposed between the piezoelectric element and the curved surface along a vertical direction. The adhesive attaches the piezoelectric element to the substrate. The adhesive has an exterior bond surface that has a tapered shape along the vertical direction from the piezoelectric element to the curved surface.

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.

A piezoelectric device includes a piezoelectric vibrating piece, a base, a wire, a conductive adhesive, and a buffer layer. The piezoelectric vibrating piece includes excitation electrodes and extraction electrodes at both principal surfaces. The base includes the piezoelectric vibrating piece and a first wiring electrode and a second wiring electrode connected to the extraction electrodes. The wire connects the extraction electrode on a surface opposite to a side of the base among the extraction electrodes to one wiring electrode of the first wiring electrode and the second wiring electrode. The conductive adhesive connects the extraction electrode at the base side among the extraction electrodes to the other wiring electrode among the first wiring electrode and the second wiring electrode. The buffer layer reduces stress of the wire between the extraction electrode to which the wire is connected and the piezoelectric vibrating piece.

A composite substrate is resistant to the development of cracks, thereby not having deteriorating properties even when exposed to high-temperatures or low temperatures, and a method is provided for producing the composite substrate. The composite substrate 10 of the present invention has a supporting substrate 2, a stress relaxing interlayer 3, and an oxide single-crystal thin film 1 stacked in the listed order. The stress relaxing interlayer 3 has a thermal expansion coefficient between that of the supporting substrate 2 and that of the oxide single-crystal thin film 1.