Abstract: An acoustic wave device includes acoustic wave resonators each including a piezoelectric substrate including a piezoelectric body layer, and an IDT electrode on the piezoelectric substrate and including electrode fingers. At least one of the acoustic wave resonators is an excitation angle change resonator, in which, the piezoelectric body layer includes a propagation axis and the electrode fingers are curved. In the excitation angle change resonator, an excitation direction of an acoustic wave in a portion of one of the electrode fingers is one of first, second, or third directions. An excitation angle of the excitation angle change resonator is not uniform in the IDT electrode.

Abstract: A filter device includes a first signal terminal, a second signal terminal, and a plurality of resonators including a plurality of series arm resonators and a plurality of parallel arm resonators. At least one of the plurality of series arm resonators and the plurality of parallel arm resonators is an excitation angle change resonator. The excitation angle change resonator includes a piezoelectric substrate including a piezoelectric body layer, and an IDT electrode including a plurality of electrode fingers provided on the piezoelectric substrate. The piezoelectric body layer has a propagation axis. The plurality of electrode fingers are curved. An excitation direction of an acoustic wave in a portion of an electrode finger in the plurality of electrode fingers is one of first to third directions.

Abstract: An acoustic wave device includes a piezoelectric substrate including a piezoelectric layer, and IDT electrodes on the piezoelectric substrate and including curved IDT electrodes. A direction in which a portion of the electrode finger with a curved shape in the curved IDT electrode is convex is an outer side direction. Acoustic wave resonators include first and second acoustic wave resonators including first and second curved IDT electrodes, respectively. The first and second acoustic wave resonators are connected without another acoustic wave resonator interposed therebetween. When one of the directions in which electrode fingers are arranged is a first direction and a direction opposite to the first direction is a second direction, the outer side direction in the first IDT electrode is the first direction, and the outer side direction of the second IDT electrode is the second direction.

Abstract: Disclosed is a structural vibration damping device, which comprises a piezoelectric element adapted to be mounted on a structure, a shunt circuit inserted between two electrodes of the piezoelectric element, and an electric circuit for selectively opening and closing the shunt circuit. In this damping device, the electric circuit is operable, when a voltage between the electrodes of the piezoelectric element has a positive or negative extreme value due to a vibration of the structure, to close the shunt circuit so as to allow a current to flow between the electrodes of the piezoelectric element, and, when the current is reduced to zero, to open the shunt circuit so as to preclude the current flow until a voltage between the electrodes of the piezoelectric element subsequently has the extreme value. Further, each of the shunt circuit and the electric circuit is designed to be operated using only a power generated by the piezoelectric element.

Abstract: Disclosed is a structural vibration damping device, which comprises a piezoelectric element adapted to be mounted on a structure, a shunt circuit inserted between two electrodes of the piezoelectric element, and an electric circuit for selectively opening and closing the shunt circuit. In this damping device, the electric circuit is operable, when a voltage between the electrodes of the piezoelectric element has a positive or negative extreme value due to a vibration of the structure, to close the shunt circuit so as to allow a current to flow between the electrodes of the piezoelectric element, and, when the current is reduced to zero, to open the shunt circuit so as to preclude the current flow until a voltage between the electrodes of the piezoelectric element subsequently has the extreme value. Further, each of the shunt circuit and the electric circuit is designed to be operated using only a power generated by the piezoelectric element.