Abstract: An acoustic wave device includes a piezoelectric substrate including a support including a support substrate and a piezoelectric layer on the support, a functional electrode on the piezoelectric layer, at least one support, and a lid. One of the at least one support surrounds the functional electrode on the piezoelectric substrate and the lid is provided on the support. A first cavity is provided in the support. The first cavity overlaps at least a portion of the functional electrode in plan view. A second cavity is surrounded by the piezoelectric substrate, a support provided between the piezoelectric substrate and the lid, and the lid. A height of the first cavity is greater than a height of the second cavity.

Abstract: An acoustic wave device includes a silicon oxide film, a piezoelectric body, and an interdigital transducer electrode laminated on a support substrate made of silicon. Where a wave length that is determined by an electrode finger pitch of the interdigital transducer electrode is ?, a thickness of the support substrate is greater than or equal to about 3?. An acoustic velocity of the first higher mode that propagates through the piezoelectric body is an acoustic velocity VSi=(V1)1/2 of bulk waves that propagate in the support substrate, which is determined by V1 out of solutions V1, V2, and V3 of x derived from the mathematical expression Ax3+Bx2+Cx+D=0, or higher than VSi.

Abstract: An acoustic wave device includes a silicon oxide film, a piezoelectric body, and an interdigital transducer electrode laminated on a support substrate made of silicon. Where a wave length that is determined by an electrode finger pitch of the interdigital transducer electrode is ?, a thickness of the support substrate is greater than or equal to about 3?. An acoustic velocity of the first higher mode that propagates through the piezoelectric body is an acoustic velocity VSi=(V1)1/2 of bulk waves that propagate in the support substrate, which is determined by V1 out of solutions V1, V2, and V3 of x derived from the mathematical expression Ax3+Bx2+Cx+D=0, or higher than VSi.

Abstract: An electronic component includes a support member, a piezoelectric film, and an interdigital transducer. The support member includes silicon as a primary component. The piezoelectric film is provided directly or indirectly on the support member. The interdigital transducer includes a plurality of electrode fingers. The plurality of electrode fingers are provided side by side separately from each other. The interdigital transducer is provided on the principal surface of the piezoelectric film. The film thickness of the piezoelectric film is about 3.5 ? or less, where ? denotes the wavelength of an acoustic wave determined by the electrode finger pitch of the interdigital transducer. In the support member, the high-impurity-concentration region is further from the piezoelectric film than the low-impurity-concentration region.

Abstract: An acoustic wave device includes a silicon oxide film, a piezoelectric body, and an interdigital transducer electrode laminated on a support substrate made of silicon. Where a wave length that is determined by an electrode finger pitch of the interdigital transducer electrode is ?, a thickness of the support substrate is greater than or equal to about 3?. An acoustic velocity of the first higher mode that propagates through the piezoelectric body is an acoustic velocity Vsi=(V1)1/2 of bulk waves that propagate in the support substrate, which is determined by V1 out of solutions V1, V2, and V3 of x derived from the mathematical expression Ax3+Bx2+Cx+D=0, or higher than Vsi.

Abstract: An acoustic wave device including series arm resonators including a first IDT electrode and parallel arm resonators including a second IDT electrode, in the first IDT electrode, a first envelope obliquely extends with respect to the acoustic wave propagation direction, and a second envelope obliquely extends with respect to the acoustic wave propagation direction, the second IDT electrode includes a central region, a first low acoustic velocity region in which an acoustic velocity is lower than an acoustic velocity in the central region, a second low acoustic velocity region in which an acoustic velocity is lower than the acoustic velocity in the central region, a first high acoustic velocity region in which an acoustic velocity is higher than the acoustic velocity in the central region, and a second high acoustic velocity region in which an acoustic velocity is higher than the acoustic velocity in the central region.

Abstract: An acoustic wave device includes a piezoelectric layer and first and second electrodes facing each other in a direction crossing a thickness direction of the piezoelectric layer. The acoustic wave device utilizes a bulk wave of a thickness slip first-order mode. The acoustic wave device includes first and second resonators. Each of the first and second resonators includes the first and second electrodes, and a setting portion including a setup region where the first and second electrodes are provided in the piezoelectric layer. The thickness of each of the first and second resonators excludes the thickness of the first and second electrodes included in the resonator. The thickness of the first resonator is different from the thickness of the second resonator.

Abstract: An acoustic wave device includes a piezoelectric layer, at least one pair of electrodes adjacent to each other, and an additional film. The piezoelectric layer is made of lithium niobate or lithium tantalate, and includes first and second opposing principal surfaces. The at least one pair of electrodes is located on the first principal surface of the piezoelectric layer. The additional film is located on the piezoelectric layer or either one or both of the electrodes so as to overlap, in plan view, either one or both of areas in which the electrodes are located and an area between the electrodes. When d represents a thickness of the piezoelectric layer and p represents a center-to-center distance between the electrodes, d/p is equal to or less than about 0.5.

Abstract: An acoustic wave device includes a piezoelectric layer and first and second electrodes facing each other in a direction crossing a thickness direction of the piezoelectric layer. The acoustic wave device utilizes a bulk wave of a thickness slip first-order mode. The acoustic wave device includes first and second resonators. Each of the first and second resonators includes the first and second electrodes, and a setting portion including a setup region where the first and second electrodes are provided in the piezoelectric layer. The thickness of each of the first and second resonators excludes the thickness of the first and second electrodes included in the resonator. The thickness of the first resonator is different from the thickness of the second resonator.

Abstract: An object is to provide a supercharging system capable of actively and easily controlling a rotational speed of a turbine generator. A supercharging system includes a compressor driven by an electric motor to pump fluid to an engine, a turbine generator rotated by exhaust from the engine, and a drive device that drives the electric motor by electricity generated by the turbine generator, wherein the drive device includes a rectifying unit that rectifies the electricity generated by the turbine generator, a converter unit that steps up or down a voltage value of a DC voltage rectified by the rectifying unit and outputs the DC voltage, an inverter unit that drives the electric motor using the DC voltage output from the converter unit, and a control unit that controls a change amount of the DC voltage in the converter unit.

Abstract: An acoustic wave device includes a piezoelectric substrate, an interdigital transducer electrode on the piezoelectric substrate, and reflectors. The interdigital transducer electrode includes first and second busbars including first and second cavities in a first direction, and first and second edge regions and first and second gap regions. The first and second edge regions include low acoustic velocity regions. Regions in which the first and second cavities are provided include high acoustic velocity regions. The reflector includes first and second reflector busbars and first reflection electrode fingers each including a second end portion that faces the second reflector busbar. The first reflection electrode fingers overlap the entire or substantially the entire second gap region when viewed in the first direction.

Abstract: An acoustic wave device includes a support substrate and first and second resonant sections adjacent to each other on the support substrate. Each of the first and second resonant sections includes a piezoelectric thin film, an IDT electrode on the piezoelectric thin film, and a support layer surrounding the piezoelectric thin film in a plan view of the acoustic wave device. The support layer has a different linear expansion coefficient from the piezoelectric thin film. The piezoelectric thin film in the first resonant section and the piezoelectric thin film in the second resonant section are divided by the support layer between the resonant section and the resonant section.

Abstract: An elastic wave device includes a multilayer film stacked on a support substrate. A first support layer surrounds a region including interdigital transducer electrodes. A second support layer is disposed in the region surrounded by the first support layer. A cover is fixed on the first support layer and the second support layer so as to close a cavity defined by the first support layer. The multilayer film is partially disposed on the support substrate, and an insulating layer is disposed in at least a portion of a region in which the multilayer film is not disposed. At least one of the first support layer and the second support layer is disposed on the insulating layer.

Abstract: An acoustic wave device including series arm resonators including a first IDT electrode and parallel arm resonators including a second IDT electrode, in the first IDT electrode, a first envelope obliquely extends with respect to the acoustic wave propagation direction, and a second envelope obliquely extends with respect to the acoustic wave propagation direction, the second IDT electrode includes a central region, a first low acoustic velocity region in which an acoustic velocity is lower than an acoustic velocity in the central region, a second low acoustic velocity region in which an acoustic velocity is lower than the acoustic velocity in the central region, a first high acoustic velocity region in which an acoustic velocity is higher than the acoustic velocity in the central region, and a second high acoustic velocity region in which an acoustic velocity is higher than the acoustic velocity in the central region.

Abstract: An elastic wave device includes an IDT electrode on a piezoelectric substrate to define a longitudinally coupled resonator elastic wave filter, a three-dimensional wiring portion on the piezoelectric substrate and connected to the longitudinally coupled resonator elastic wave filter, and a cover surrounding the longitudinally coupled resonator elastic wave filter on the piezoelectric substrate. The three-dimensional wiring portion includes a lower layer wiring line, an upper layer wiring line, and an insulating layer stacked between the lower layer wiring line and the upper layer wiring line. The cover includes a portion on the three-dimensional wiring portion.

Abstract: An electronic component includes a support member, a piezoelectric film, and an interdigital transducer. The support member includes silicon as a primary component. The piezoelectric film is provided directly or indirectly on the support member. The interdigital transducer includes a plurality of electrode fingers. The plurality of electrode fingers are provided side by side separately from each other. The interdigital transducer is provided on the principal surface of the piezoelectric film. The film thickness of the piezoelectric film is about 3.5? or less, where ? denotes the wavelength of an acoustic wave determined by the electrode finger pitch of the interdigital transducer. In the support member, the high-impurity-concentration region is further from the piezoelectric film than the low-impurity-concentration region.

Abstract: An object is to provide a supercharging system capable of actively and easily controlling a rotational speed of a turbine generator. A supercharging system includes a compressor driven by an electric motor to pump fluid to an engine, a turbine generator rotated by exhaust from the engine, and a drive device that drives the electric motor by electricity generated by the turbine generator, wherein the drive device includes a rectifying unit that rectifies the electricity generated by the turbine generator, a converter unit that steps up or down a voltage value of a DC voltage rectified by the rectifying unit and outputs the DC voltage, an inverter unit that drives the electric motor using the DC voltage output from the converter unit, and a control unit that controls a change amount of the DC voltage in the converter unit.

Abstract: A method of detecting a damage of a wind turbine blade of a wind turbine rotor includes: a light input step of inputting light into a fiber-optic sensor mounted to the wind turbine blade; a light detection step of detecting reflection light from the grating portion; an obtaining step of obtaining a wavelength fluctuation index representing a fluctuation amount of a wavelength of the reflection light detected in the light detection step; and a detection step. The detection step includes detecting the presence or the absence of the damage of the wind turbine blade based on the wavelength fluctuation index taking account of a correlation between the wavelength fluctuation index of the wind turbine blade and a load index related to a load applied to the wind turbine blade, or a correlation between the wavelength fluctuation index and a temperature index related to a temperature of the wind turbine blade.

Abstract: An acoustic wave device includes a silicon oxide film, a piezoelectric body, and an interdigital transducer electrode laminated on a support substrate made of silicon. Where a wave length that is determined by an electrode finger pitch of the interdigital transducer electrode is ?, a thickness of the support substrate is greater than or equal to about 3?. An acoustic velocity of the first higher mode that propagates through the piezoelectric body is an acoustic velocity Vsi=(V1)1/2 of bulk waves that propagate in the support substrate, which is determined by V1 out of solutions V1, V2, and V3 of x derived from the mathematical expression Ax3+Bx2+Cx+D=0, or higher than Vsi.