Elastic wave filter device

An elastic wave filter device comprising:

• a piezoelectric film including:
• a high acoustic velocity member in which an acoustic velocity of a propagating bulk wave is larger than an acoustic velocity of a main mode elastic wave propagating in the piezoelectric film;
• the piezoelectric film being made of a piezoelectric single crystal and laminated directly or indirectly on the high acoustic velocity member;
• and
• a plurality of IDT electrodes in contact with the piezoelectric film;
• wherein
• the elastic wave filter device includes an input terminal, an output terminal, a serial arm connecting the input terminal and the output terminal, and a parallel arm connecting the serial arm and a ground potential;
• at least one serial arm resonator and at least one parallel arm resonator are defined by the plurality of IDT electrodes;
• the plurality of IDT electrodes defining the at least one serial arm resonator and the at least one parallel arm resonator include a plurality of first electrode fingers and a plurality of second electrode fingers that are interdigitated with one another, and a direction in which tips of the plurality of first electrode fingers are connected and a direction in which tips of the plurality of second electrode fingers are connected are tilted to define a tilt angle ν with respect to a propagation direction ψ of elastic waves being excited by the IDT electrodes, that is defined by Euler angles (φ, θ, ψ) of the piezoelectric single crystal;
• and
• when the tilt angle of the at least one serial arm resonator is denoted as ν1 and the tilt angle of the at least one parallel arm resonator is denoted as ν2, the tilt angle ν1 differs from the tilt angle ν2.