Abstract: An object is to provide an organic piezoelectric film with a high level of piezoelectricity and a high level of transparency. The organic piezoelectric film of the present disclosure has a total light transmittance of 90% or more, an internal haze value of 0.2%/?m or less per unit film thickness or an internal haze value of 4% or less, and piezoelectric constant d33 of 10 pC/N or more after heating at 110° C. for 10 minutes.

Abstract: An object is to provide an organic piezoelectric film with a high level of piezoelectricity, a high level of transparency, and a low level of retardation. The organic piezoelectric film of the present disclosure has a total light transmittance of 90% or more, an internal haze value of 0.2%/?m or less per unit film thickness or an internal haze value of 4% or less, piezoelectric constant d33 of 13 pC/N or more, and a retardation within the range of 0.01 to 10 nm/?m per unit film thickness or a retardation within the range of 0.1 to 900 nm.

Abstract: An object of the present invention is to provide a vibration sensor in which the frequency dependence of the output is small. The present invention provides a vibration sensor 1 comprising: a support 2; an organic piezoelectric material 3 deformably disposed in or on the support 2; and an electrode 4 for extracting an electrical signal generated by deformation of the organic piezoelectric material 3, the electrode 4 being formed on the organic piezoelectric material 3, the organic piezoelectric material 3 comprising a copolymer of vinylidene fluoride and one or more monomers copolymerizable with vinylidene fluoride.

Abstract: An object is to provide a fluorine-containing polymer film. The object can be achieved by a fluorine-containing polymer film having a thermal shrinkage of 0.4% or less after being heated at 90° C. for 1 hour, and having a relative permittivity of 3 to 50 at 25° C. at 1000 Hz, or a fluorine-containing polymer film having a crystallinity of 50% or more and an elongation at break of 400% or more.

Abstract: The present invention addresses the problem of providing a bimorph-type piezoelectric film that is less susceptible to the influence of pyroelectric noise resulting from temperature changes, and that makes it possible to provide a pressure-sensitive sensor or the like. The present invention provides a bimorph-type piezoelectric film comprising a first pyroelectric film having piezoelectric anisotropy in an in-plane direction, and a second pyroelectric film having piezoelectric anisotropy in an in-plane direction, the first pyroelectric film and the second pyroelectric film being disposed in such a manner that their surfaces on which electric charges of the same polarity are generated by a temperature increase are each outward-facing.

Abstract: An object is to provide a piezoelectric film with good piezoelectricity. This object can be achieved by a piezoelectric film comprising a vinylidene fluoride/tetrafluoroethylene copolymer film and having a residual polarization amount of 40 mC/m2 or more.

Abstract: The present invention addresses the problem of providing a bimorph-type piezoelectric film that is less susceptible to the influence of pyroelectric noise resulting from temperature changes, and that makes it possible to provide a pressure-sensitive sensor or the like. The present invention provides a bimorph-type piezoelectric film comprising a first pyroelectric film having piezoelectric anisotropy in an in-plane direction, and a second pyroelectric film having piezoelectric anisotropy in an in-plane direction, the first pyroelectric film and the second pyroelectric film being disposed in such a manner that their surfaces on which electric charges of the same polarity are generated by a temperature increase are each outward-facing.

Abstract: An object of the present invention is to provide a vibration sensor in which the frequency dependence of the output is small. The present invention provides a vibration sensor 1 comprising: a support 2; an organic piezoelectric material 3 deformably disposed in or on the support 2; and an electrode 4 for extracting an electrical signal generated by deformation of the organic piezoelectric material 3, the electrode 4 being formed on the organic piezoelectric material 3, the organic piezoelectric material 3 comprising a copolymer of vinylidene fluoride and one or more monomers copolymerizable with vinylidene fluoride.