A dielectric elastomer actuator comprising: a plurality of polymer layer; a plurality of stretchable electrode layers, each polymer layer being sandwiched between two electrode layers so as to control the electric field within the polymer layer; at least one stretchable charge distribution layer, each charge distribution layer being adjacent to one stretchable electrode layer and/or to one polymer layer.

An ultrasonic sensor includes a piezoelectric body including first and second surfaces. First and second electrodes are respectively provided on the first and second surfaces. The second electrode is opposed to the first electrode with the piezoelectric body interposed therebetween. A third electrode is provided on the second surface. The third electrode is spaced apart from the second electrode. The third electrode is electrically connected to the first electrode. When viewed from a thickness direction in which the first surface and the second surface are arranged, the second electrode extends to both end edges of the second surface in a first direction and is spaced apart from both end edges of the second surface in a second direction orthogonal to the first direction.

As a temperature measurement apparatus using a surface acoustic wave of a piezoelectric substrate that performs temperature measurement wirelessly and without power supply, the temperature measurement apparatus accurately measures the temperature of the thermocouple tip end by analyzing the frequency characteristics of the surface acoustic wave propagating on the piezoelectric substrate and including temperature information of the piezoelectric substrate, and detecting change in propagation time of the surface acoustic wave of the piezoelectric substrate that is changed by the electromotive force of the thermocouple.

Disclosed is a device that includes a crystalline substrate and a patterned aluminum-based material layer disposed onto the crystalline substrate. The patterned aluminum-based material layer has a titanium-alloyed surface. A titanium-based material layer is disposed over select portions of the titanium-alloyed surface. In an exemplary embodiment, the patterned aluminum-based material layer forms a pair of interdigitated transducers to provide a surface wave acoustic (SAW) device. The SAW device of the present disclosure is usable to realize SAW-based filters for wireless communication equipment.

An ultrasonic fingerprint recognition sensor and a manufacturing method thereof, and a display device are disclosed. The ultrasonic fingerprint recognition sensor includes a resonant cavity, a receiver electrode, a drive electrode, and a piezoelectric thin film layer between the receiver electrode and the drive electrode, the resonant cavity is on a side, closer to the piezoelectric thin film layer, of the receiver electrode, and is configured to increase vibration amplitude of the piezoelectric thin film layer.

An electronic device includes a substrate layer having a front surface and a back surface opposite the front surface, a plurality of ultrasonic transducers formed on the front surface of the substrate layer, wherein the plurality of ultrasonic transducers generate backward waves during operation, the backward waves propagating through the substrate layer, and a plurality of substrate structures formed within the back surface of the substrate layer, the plurality of substrate structures configured to modify the backward waves during the operation.

A piezoelectric actuator includes a first electrode, a first piezoelectric body disposed at one side of the first electrode in a thickness direction of the first electrode, an individual electrode disposed at one side of the first piezoelectric body in the thickness direction, a second piezoelectric body disposed at one side of the individual electrode in the thickness direction, a second electrode disposed at one side of the second piezoelectric body in the thickness direction, a wiring that electrically connects to the individual electrode, a first contact, and a second contact. At the first and the second contacts, the first electrode and the second electrode electrically connect to each other. The first contact is disposed at one side of the individual electrode in a perpendicular direction perpendicular to the thickness direction. The second contact is disposed at the other side of the individual electrode in the perpendicular direction.

A micro crystal oscillator includes: a tank body including a tank bottom and a side wall, the tank bottom including an inner surface and an outer surface, wherein the side wall is disposed on a periphery of the inner surface of the tank bottom to form a recess together with the tank bottom; a plurality of patterned electrodes arranged on the outer surface; a first patterned circuit arranged on the side wall; a plurality of vias disposed in the tank body for electrically connecting at least one of the patterned electrodes to the first patterned circuit; an oscillating chip arranged on the inner surface and located in the recess; and a plurality of connecting wires located in the recess and respectively connected to the oscillating chip and the first patterned circuit in a wire bonding manner; wherein the micro crystal oscillator is of millimeter level.

An object of the present invention is to provide a piezoelectric film capable of realizing an electroacoustic conversion film or the like in which the durability is high and a sufficient sound pressure with respect to an input operating voltage is obtained. The object is achieved by providing a piezoelectric film including a polymer-based piezoelectric composite material which contains piezoelectric particles in a matrix containing a polymer material, and electrode layers which are provided on both surfaces of the polymer-based piezoelectric composite material, in which in a case where a cross section of the film in a thickness direction is observed with a scanning electron microscope, the polymer-based piezoelectric composite material is divided into ten equal regions in the thickness direction, area ratios of the piezoelectric particles in two most distant regions are measured, and the area ratio of the piezoelectric particles in the region with a lower area ratio is set as 1, the area ratio of the piezoelectric particles in the region with a higher area ratio is 1.2 or greater.

In a piezoelectric device, when viewed in a direction perpendicular to one main surface, an outer shape of a recess is a polygonal shape or a circular shape. When n represents a number of sides of the polygonal shape, r represents a radius of a circumscribed circle of an imaginary regular polygon including n sides with a length identical to a length of a shortest of the sides, and d represents a maximum thickness of a membrane portion, which is located above the recess, of a multilayer portion, r≤197.7dn.sup.−0.6698 when 3≤n≤7, and r≤52.69d when 8≤n or when the outer shape of the recess is a circular shape.