Patent ID: 10669397

Abstract:
A polymeric piezoelectric film, including a helical chiral polymer (A) having a weight average molecular weight of from 50,000 to 1,000,000 and optical activity, in which, in the film: a crystallinity given by a DSC method is from 20% to 80%; a standardized molecular orientation MORc is from 3.5 to 15.0 when a reference thickness measured by a microwave transmission-type molecular orientation meter is 50 μm; and when a direction parallel to a phase difference streak is a direction X, a direction perpendicular to the direction X and parallel to a main plane of a film is a direction Y, and the phase difference streak is evaluated by an evaluation method A, per a length of 1,000 mm in the direction Y, a number of phase difference streaks with an evaluation value of 60 or more is 0, and a sum of the evaluation values of phase difference streaks with an evaluation value of 20 or more is 1000 or less.