An acoustic resonator device includes a substrate having a surface and a piezoelectric plate having front and back surfaces, with the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. Stripes of a dielectric material formed over the plate in gaps between ends of the interleaved fingers and opposing busbars of the IDT.

An acoustic wave device including an IDT electrode on a piezoelectric film, in which a Z-axis direction of a crystal is different from a direction of a normal to a major surface. An overlap region of the IDT electrode includes a central region and first and second edge regions. First and second dielectric films are stacked between the piezoelectric film and first and second electrode fingers in the first and second edge regions. When an angle between a first side surface of the first dielectric film and a major surface of the piezoelectric film is α1 and an angle between a second side surface of the second dielectric film and the major surface of the piezoelectric film is α2, α1≠α2 between at least one electrode finger of the first and second electrode fingers and the piezoelectric film.

A ladder type acoustic wave filter is disclosed. The acoustic wave filter can include a plurality of parallel arm resonators and a plurality of series arm resonators, in which an electromechanical coupling coefficient of a parallel arm resonator closest to an input node of the acoustic wave filter among the plurality of parallel arm resonators can be smaller than an electromechanical coupling coefficient of a series arm resonator closest to the input node among the plurality of series arm resonators.

This method for manufacturing a hermetic sealing lid member (1, 201, 301) includes forming a Ni plated metal plate (70, 170) by forming a Ni plated layer (11, 12, 41) on a surface of a metal plate (40) having a corrosion resistance and forming the hermetic sealing lid member by punching the Ni plated metal plate.

A filter includes a piezoelectric film including lithium niobate or lithium tantalate, an acoustic wave resonator including a functional electrode on the piezoelectric film, a capacitor on the piezoelectric film and connected in parallel to the acoustic wave resonator, and a resonator electrically connected to the acoustic wave resonator. The functional electrode includes a pair of first and second electrodes facing each other in a direction intersecting a thickness direction of the piezoelectric film. When a thickness of the piezoelectric film is d and a center-to-center distance between the first electrode and the second electrode is p, d/p is smaller than or equal to about 0.5.

A filter includes a series resonator or a longitudinally coupled resonator on a path connecting a first input-and-output terminal and a second input-and-output terminal, and parallel resonators each connected between the path and a ground. Among the parallel resonators, a second parallel resonator and a first parallel resonator are connected in parallel without another resonator being interposed therebetween. An IDT electrode of the first parallel resonator includes different electrode finger pitches. An average of all the electrode finger pitches of the IDT electrode of the first parallel resonator is larger than an average of all the electrode finger pitches of an IDT electrode of the second parallel resonator.

Embodiments of the invention include a waveguide structure that includes a first piezoelectric transducer that is positioned in proximity to a first end of a cavity of an organic substrate. The first piezoelectric transducer receives an input electrical signal and generates an acoustic wave to be transmitted with a transmission medium. A second piezoelectric transducer is positioned in proximity to a second end of the cavity. The second piezoelectric transducer receives the acoustic wave from the transmission medium and generates an output electrical signal.

[PROBLEM TO BE SOLVED] To provide a bulk wave resonator having a high frequency passband.

[SOLUTION] A bulk wave resonator using a bulk wave, includes a support substrate, an acoustic multilayer film that includes, stacked on the support substrate, a plurality of types of dielectrics having different acoustic impedances, a piezoelectric layer that is stacked on the acoustic multilayer film, a first electrode, and a second electrode. The first and second electrodes are disposed to face each other with a gap therebetween on a first surface of the piezoelectric layer opposite to the acoustic multilayer film, and are applied with a voltage for allowing the piezoelectric layer to generate the bulk wave. A direction that is parallel to the surface of the piezoelectric layer and in which the first electrode and the second electrode face each other is defined as a first direction. The bulk wave resonator uses, as a main mode, a bulk wave in the first direction that is generated by a thickness shear vibration in the first direction, which is excited by a parallel electric field formed in the piezoelectric layer when a voltage applied to the first electrode and the second electrode.

An acoustic wave device includes a first piezoelectric layer that is a rotated Y-cut lithium tantalate substrate and has a first thickness, a second piezoelectric layer that is a rotated Y-cut lithium niobate substrate, is stacked on the first piezoelectric layer, has a second thickness that is less than the first thickness, and has a spontaneous polarization direction that is substantially opposite to a spontaneous polarization direction of the first piezoelectric layer, a first electrode provided on an opposite surface of the first piezoelectric layer from the second piezoelectric layer, and a second electrode that is provided on an opposite surface of the second piezoelectric layer from the first piezoelectric layer, at least a part of the first piezoelectric layer and at least a part of the second piezoelectric layer being interposed between the first electrode and the second electrode.

A bulk acoustic resonator having a heat dissipation structure, and a fabrication process are provided according to the present application. The bulk acoustic resonator includes a substrate, a metal heat dissipation layer formed on the base substrate and provided with an insulating layer on the surface thereof, and a resonance functional layer formed on the insulating layer, where the metal heat dissipation layer and the insulating layer together define a cavity on the substrate, a side wall of the cavity is formed by the insulating layer, and a bottom electrode layer in the resonance function layer covers the cavity.