Patent ID: 8344590

Claim:
An acoustic wave device comprising a main resonator and a sub resonator each having a substrate, a lower electrode provided on the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on an upper side of the piezoelectric film, the sub resonator having a mass addition film on the upper electrode in a resonance area in which the upper electrode and the lower electrode face each other, at least one of the main resonator and the sub resonator being provided with a frequency control film on an upper side of the resonance area, and the frequency control film having a weight per unit area smaller than a weight of the mass addition film per unit area and having patterns of a convex or concave shape, and the patterns being formed in a dispersed form in the resonance area, wherein: the main resonator does not have the mass addition film; and the main resonator is a series resonator of a ladder type filter and the sub resonator is a parallel resonator of the ladder type filter.