Piezoelectric and pyroelectric film and method for preparing the film

摘要

A piezoelectric and pyroelectric film made from a resin composition of polymer of vinylidene fluoride, which is characterized by an index of birefringence of larger than 3x10-3 and a ratio of d31/d32 of 0.3 to 3.0, and which may be prepared by further stretching a biaxially stretched film made from the above-mentioned resin composition at a temperature lower than the temperature of the biaxially stretching by more than 20 DEG C. before or at the same time of a treatment for orientation polarization of the film.