Acoustic wave device

An acoustic wave device comprising:

• a piezoelectric film in which a Z-axis direction of a crystal is different from a direction of a normal to a major surface;
• and
• an IDT electrode on the major surface of the piezoelectric film;
• wherein
• the IDT electrode includes:
• first and second busbars;
• a plurality of first electrode fingers connected to the first busbar;
• and
• a plurality of second electrode fingers connected to the second busbar;
• the plurality of first electrode fingers and the plurality of second electrode fingers are interdigitated with each other;
• a region in which the first electrode fingers and the second electrode fingers are overlapped with each other in a direction in which an acoustic wave is propagated is an overlap region;
• the overlap region includes:
• a central region;
• a first edge region located on a first busbar side of the central region in a direction in which the first and second electrode fingers extend;
• and
• a second edge region located on a second busbar side of the central region in the direction in which the first and second electrode fingers extend;
• the acoustic wave device further comprises, in the first and second edge regions, first and second dielectric films each located between the major surface of the piezoelectric film and the first and second electrode fingers;
• the first dielectric film includes, in the first edge region, a first side surface located on the second busbar side;
• the second dielectric film includes, in the second edge region, a second side surface located on the first busbar side;
• and
• when an angle between the first side surface and the major surface of the piezoelectric film is denoted by α1 and an angle between the second side surface and the major surface of the piezoelectric film is denoted by α2, α1≠α2 is satisfied between at least one electrode finger of the plurality of first and second electrode fingers and the piezoelectric film.