Piezoelectric film
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%/μm or less per unit film thickness or an internal haze value of 4% or less, piezoelectric constant d 33 of 13 pC/N or more, and a retardation within the range of 0.01 to 10 nm/μm per unit film thickness or a retardation within the range of 0.1 to 900 nm.
1 . An organic piezoelectric film, having
a total light transmittance of 90% or more,
an internal haze value of 0.2%/μm or less per unit film thickness,
a piezoelectric constant d 33 of 14 pC/N or more,
a retardation within the range of 0.01 to 10 nm/μm per unit film thickness, and
a film thickness of 1 to 1000 μm.
2 . An organic piezoelectric film having
a total light transmittance of 90% or more,
an internal haze value of 4% or less,
a piezoelectric constant d 33 of 14 pC/N or more,
a retardation within the range of 0.1 to 900 nm, and
a film thickness of 1 to 1000 μm.
3 . The organic piezoelectric film according to claim 1 , comprising a vinylidene fluoride-based copolymer film.
4 . The organic piezoelectric film according to claim 3 , wherein the vinylidene fluoride-based copolymer is at least one member selected from the group consisting of vinylidene fluoride-tetrafluoroethylene copolymers and vinylidene fluoride-trifluoroethylene copolymers.
5 . The organic piezoelectric film according to claim 3 , wherein the vinylidene fluoride-based copolymer is a vinylidene fluoride-trifluoroethylene copolymer.
6 . The organic piezoelectric film according to claim 3 , wherein the proportion of vinylidene fluoride in the vinylidene fluoride-based copolymer is within the range of 60 to 85 mol %.
7 . The organic piezoelectric film according to claim 1 , for use in one or more members selected from the group consisting of sensors, actuators, touch panels, haptic devices, vibration-powered generators, speakers, and microphones.
8 . A piezoelectric material that is a laminate, the piezoelectric material comprising:
the organic piezoelectric film of claim 1 , and
an electrode provided on at least one surface of the organic piezoelectric film.