Elastic wave device and ladder filter

An elastic wave device comprising:

• a support substrate including a first main surface and a recessed portion open to the first main surface;
• a piezoelectric film made of lithium niobate or lithium tantalate, laminated on the first main surface of the support substrate and defining a cavity portion with the recessed portion together with the support substrate;
• and
• an electrode on the piezoelectric film and including first and second bus bars, a first electrode finger connected to the first bus bar, and a second electrode finger connected to the second bus bar;
• wherein
• the first and second bus bars include a plurality of corner portions when viewed in a plan view;
• when a thickness of the piezoelectric film is d and a distance between centers of the first electrode finger and second electrode finger is p, d/p is about 0.5 or less;
• and
• at least one of the plurality of corner portions of the first and second bus bars is outside the cavity portion when viewed in the plan view.

An elastic wave device comprising:

• a support substrate including a first main surface and a recessed portion at the first main surface;
• a piezoelectric film laminated on the first main surface of the support substrate and defining a cavity portion with the recessed portion;
• and
• an interdigital transducer (IDT) electrode on the piezoelectric film so that a portion of the IDT electrode overlaps the cavity portion;
• wherein
• the IDT electrode includes first and second bus bars, a plurality of first electrode fingers connected to the first bus bar, and a plurality of second electrode fingers connected to the second bus bar;
• the plurality of first electrode fingers and the plurality of second electrode fingers are interleaved with each other;
• the first and second bus bars include a plurality of corner portions when viewed in a plan view;
• and
• at least one of the plurality of corner portions of the first and second bus bars is outside the cavity portion when viewed in the plan view.