A fingerprint sensor device includes a sensor substrate, a plurality of sensor circuits over a first surface of the sensor substrate, and a transceiver layer located over the plurality of sensor circuits and the first surface of the sensor substrate. The transceiver layer includes a piezoelectric layer and a transceiver electrode positioned over the piezoelectric layer. The piezoelectric layer and the transceiver electrode are configured to generate one or more ultrasonic waves or to receive one or more ultrasonic waves. The fingerprint sensor device may include a cap coupled to the sensor substrate and a cavity formed between the cap and the sensor substrate. The cavity and the sensor substrate may form an acoustic barrier.

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.

The electrical energy conversion system comprises: a converter including E first switching assembly or assemblies, each associated with an input voltage and including two first switches; N second switching assembly or assemblies, each associated with an output voltage and including two second switches; and at least one piezoelectric assembly connected to a switch; E>1, N>1; a control device configured for controlling, during a resonance cycle, a switching of the switches so as to alternate phases at constant voltage and phases at constant load across said piezoelectric assembly or assemblies.

The converter comprising an electrical transformer having a primary winding connected to a first switching assembly and a secondary winding connected to a second switching assembly, and each piezoelectric assembly being connected between a switch and a winding.

The electrical energy conversion system comprises: a converter including E first switching assembly or assemblies, each associated with an input voltage and including two first switches; N second switching assembly or assemblies, each associated with an output voltage and including two second switches; and at least one piezoelectric assembly connected to a switch; E>1, N>1; a control device configured for controlling, during a resonance cycle, a switching of the switches so as to alternate phases at constant voltage and phases at constant load across said piezoelectric assembly or assemblies.

The converter comprising an electrical transformer having a primary winding connected to a first switching assembly and a secondary winding connected to a second switching assembly, and each piezoelectric assembly being connected between a switch and a winding.

An elastic wave device in which a recess is provided on an upper side of a support, a piezoelectric thin film covers the recess, and an IDT electrode is provided on an upper surface of the piezoelectric thin film. A plate wave of an S0 mode or SH0 mode is used. A plurality of grooves are provided in the upper surface or lower surface of the piezoelectric thin film at a portion of the piezoelectric thin film that is positioned on a hollow section.

A piezoelectric multi-layer component includes a piezoelectric main body, which has an inlet area and an outlet area. In the outlet area or in the inlet area at least two adjacent layers are polarized antiparallel to each other and at least two adjacent layers are polarized parallel to each other.

A surface-guided bulk wave transducer includes a stack of an acoustic substrate, an electric ground plane, and a network of synchronous acoustic excitation sources with two combs of elementary piezoelectric transducers alternately interlaced two-by-two according to a periodic network step corresponding to a propagation mode of a surface-guided bulk wave of the acoustic substrate. Each elementary piezoelectric transducer includes a single and different rod with a parallelepipedal shape for which the nature, the cut of the piezoelectric material, the height h, and the width are selected for increasing the electromechanical coupling coefficient of the transducer assembly to a high level.

Provided is a surface acoustic wave device using a novel and steadily suppliable piezoelectric material that is resistant to a high-temperature environment and enables the surface acoustic wave device to use a 2 GHz to 2.5 GHz band or higher. The surface acoustic wave device includes: a piezoelectric substrate formed from a monocrystal of gehlenite (CAS: Ca2Al(AlSi)O7); and interdigital transducers formed on a surface acoustic wave propagation plane of the piezoelectric substrate.

A wireless power transmitter includes: a switching unit configured to receive a direct current (DC) voltage and to perform switching to output a first alternating current (AC) voltage; a piezoelectric transformer configured to receive the first AC voltage through a first piezoelectric element, and to output a second AC voltage corresponding to mechanical vibration of a second piezoelectric element caused by mechanical vibration of the first piezoelectric element; and a resonator configured to receive the second AC voltage to wirelessly transmit power.

This electrical energy converter comprises: a first bridge comprising at least a first switching branch between two terminals of an input voltage and including two first switches connected at a first midpoint; a second bridge comprising at least a second switching branch between two terminals of an output voltage and including two second switches connected at a second midpoint; at least one piezoelectric assembly connected between respective first and second midpoints; and at least one switching aid circuit connected to a respective midpoint and configured to, via the flow of a previously received current, discharge a parasitic capacitance of a switch of the bridge to which it is connected, and respectively charge a parasitic capacitance of another switch of said bridge.