An acoustic wave device includes a support substrate, a piezoelectric layer on the support substrate, a functional electrode on the piezoelectric layer, first and second electrode films on the piezoelectric layer, facing each other, and having different electric potentials from each other, and a dielectric film between at least one of at least a portion of the first electrode film and the piezoelectric layer and at least a portion of the second electrode film and the piezoelectric layer.

An acoustic wave device includes a support substrate, a piezoelectric layer on the support substrate, a functional electrode on the piezoelectric layer, and first and second electrode films on the piezoelectric layer, facing each other, and having different electric potentials from each other. When a region between the first and second electrode films in a plan view is an inter-electrode film region, and a region overlapping with the first electrode film or the second electrode film in a plan view is an electrode film underlying region, a thickness of the piezoelectric layer in at least a portion of the inter-electrode film region is smaller than a thickness of the piezoelectric layer in the electrode film underlying region.

An elastic wave apparatus includes a piezoelectric substrate including a main surface and a polarization axis direction having a tilt angle with respect to the main surface, an IDT electrode provided on the main surface, and at least one line on the main surface and between an end edge of the main surface and the IDT electrode. A relationship a≦316|cos(θ)|μm is satisfied where a denotes a distance from the end edge of the main surface to the IDT electrode and b≧28 μm where a dimension of the line along a direction connecting the end edge to the IDT electrode is defined as a width, b denotes the width of the line when one line is provided, and b denotes the sum of the widths of multiple lines when the multiple lines are provided.

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 filter device includes a lower electrode disposed between a substrate and a piezoelectric layer, an upper electrode disposed on the piezoelectric layer, and an insulating layer disposed on the upper electrode. The insulating layer exposes portions of the upper electrode.

An acoustic wave device includes a piezoelectric layer including first and second main surfaces and made of lithium niobate or lithium tantalate, and an interdigital transducer electrode on the first main surface and including multiple electrode fingers. d/p is about 0.5 or less where d is a thickness of the piezoelectric layer, and p is a distance between centers of adjacent electrode fingers. The electrode fingers include first and second electrode films, which include first and second surfaces and a side surface. Θ1≠Θ2 is satisfied and W1>W2 is satisfied, where Θ1 and Θ2 are angles between the side surfaces and the first surfaces of the first and second electrode films, and W1 and W2 are widths of the first and second electrode films.

A vibrating element includes a piezoelectric substrate having an excitation section adapted to excite a thickness-shear vibration, and provided with a step section in each of side surfaces on both ends, and a peripheral section having a thickness smaller than a thickness of the excitation section, and the peripheral section has at least one projection section disposed on both principal surfaces in an area where a vibratory displacement when the excitation section excites a vibration is sufficiently attenuated.

A piezoelectric component in which leakage of vibration is suppressed and vibration characteristics are excellent is provided. A piezoelectric component of the invention includes a support substrate; and a piezoelectric element mounted on the support substrate. The piezoelectric element includes electrodes (vibration electrodes) on one main surface and the other main surface of the piezoelectric element so that the electrodes have an area facing each other, and a concave area extending in a width direction of the piezoelectric element, in at least one of excepted areas which are areas other than the electrodes facing each other of the one main surface and the other main surface. At least part of corner portions of the concave area which extend in the width direction forms a curved surface.

An acoustic wave device includes: a first substrate that includes a first acoustic wave filter located on an upper surface of the first substrate; a second substrate that is flip-chip mounted on the upper surface of the first substrate through a bump, and includes a second acoustic wave filter on a lower surface of the second substrate, the lower surface of the second substrate facing the upper surface of the first substrate across an air gap; and a shield electrode that is supported by the upper surface of the first substrate, and is located between at least a part of the first acoustic wave filter and at least a part of the second acoustic wave filter through the air gap.

An acoustic wave device includes a support with a thickness in a first direction, a piezoelectric layer extending on the support in the first direction, and an interdigital transducer electrode on a principal surface of the piezoelectric layer. The interdigital transducer electrode includes first electrode fingers extending in a second direction crossing the first direction, a first busbar electrode connected to the first electrode fingers, second electrode fingers extending in the second direction and facing corresponding ones of the first electrode fingers in a third direction perpendicular or substantially perpendicular to the second direction, and a second busbar electrode connected to the second electrode fingers. The piezoelectric layer includes a piezoelectric multilayer structure in a gap region between at least one first electrode finger and the second busbar electrode, or between at least one second electrode finger and the first busbar electrode, in plan view in the first direction. The piezoelectric multilayer structure includes first and second piezoelectric bodies with different dielectric polarizations.