Piezoelectric film

Abstract

Provided is a piezoelectric film which is capable of suppressing a decrease in acoustic characteristics associated with use of a long period of time and has high durability. The piezoelectric film includes a piezoelectric layer consisting of a polymer-based piezoelectric composite material which contains piezoelectric particles in a matrix containing a polymer material and electrode layers formed on both surfaces of the piezoelectric layer, in which, in a case where a smaller value of a domain ratio X between a c domain and an a domain, which is measured by an X-ray diffraction method from one main surface side of the piezoelectric layer, or a domain ratio Y between a c domain and an a domain, which is measured by an X-ray diffraction method from the other main surface side of the piezoelectric layer, is set to 1.00, the other domain ratio is 1.05 or more.

Dependencies are inferred from the claim text.