An electrostatic protection device (10) includes: a first conductive layer (110), a second conductive layer (140) and a polarization film layer (130), in which the polarization film layer (130) is disposed between the first conductive layer (110) and the second conductive layer (140) and formed of a piezoelectric material which is capable of deforming when applied with electricity; a conductive cantilever (150), disposed on the second conductive layer (140) and including a free end (152); and a charge diffusion layer (170), disposed at a side of the conductive cantilever (150) away from the polarization film layer (130), electrically connected with the first conductive layer (110) and spaced apart from the conductive cantilever (150), in which upon a voltage difference between the first conductive layer (110) and the second conductive layer (140) reaching a predetermined value, the polarization film layer (130) deforms to allow the conductive cantilever (150) to connect with the charge diffusion layer (170). The device provides the conductive cantilever (150) which is in a suspended state in a case where the voltage difference between the first conductive layer (110) and the second conductive layer (140) does not reach the predetermined value, so the first conductive layer (110) and the second conductive layer (140) are disconnected so that the load of the first conductive layer (110) and the second conductive layer (140) are prevented from being influenced.

A piezoelectric element includes a first piezoelectric layer which has a first polarization axis direction in a thickness direction of the first piezoelectric layer and is made of AlN. A second piezoelectric layer made of GeAIN which is deposited on the first piezoelectric layer and has a second polarization axis direction opposite to the first polarization axis direction. A first electrode is provided on a side of the first piezoelectric layer which is opposite from a side where the second piezoelectric layer is disposed. A second electrode provided on a side of the second piezoelectric layer which is opposite from a side where the first piezoelectric layer is disposed.

A multi-layer piezoelectric microactuator assembly has at least one poled and active piezoelectric layer and one poled but inactive piezoelectric layer. The poled but inactive layer acts as a constraining layer in resisting expansion or contract of the first piezoelectric layer.

The present invention relates to a process for annealing a poled ceramic over a heating period during which the temperature is raised incrementally to “lock-in” desirable high temperature characteristics.

An object of the present invention is to improve the piezoelectricity of a PVT having the VDF ratio of 82 to 90% represented by a copolymer, in which copolymerization of vinylidene fluoride VDF and trifluoroethylene TrFe is 85 versus 15 (this is written as PVT85/15, and which is excellent in resistance to deformation, and heat resistance, etc. And therefore, it is also to obtain a piezoelectric film having piezoelectricity exceeding a PVT of less than 82 mol % of VDF represented by a PVT75/25, which conventionally shows the highest piezoelectricity, and a method of producing the same.

A piezoelectric film is made of a mixture of two kinds (for example, a first copolymer is PVT85/15 and a second copolymer is PVT75/25) having different polymerization ratios of vinylidene fluoride VDF and trifluoroethylene TrFE.

A method for preparing a piezoelectric film includes: coating a solution containing a piezoelectric polymer and a solvent on a substrate to obtain a film, wherein the piezoelectric polymer is a copolymer of vinylidene fluoride and trifluoroethylene; and annealing the film at a temperature ranging from 122° C. to 133° C., to obtain the piezoelectric film.

A piezoelectric device and a manufacturing method thereof in which a piezoelectric film formed of a thin film of a lead zirconate titanate-based perovskite oxide is formed on a substrate, and at least a first region out of the first region and a second region of the piezoelectric film is irradiated with electromagnetic waves having a wavelength of 230 nm or less in a reducing atmosphere to provide a difference in piezoelectric characteristics between the first region and the second region so that the first region has a smaller absolute value of a piezoelectric constant d.sub.31 and a smaller dielectric loss tan δ than the second region.

A manufacturing method for an electrode of a high-temperature piezoelectric element, comprises: coating traditional conductive slurry on surfaces of a molded piezoelectric material (1); then polarizing the piezoelectric material (1); and then removing the coating of conductive slurry (2) on the surfaces there of, and connecting the piezoelectric material to outside electrode lead wires (3) to output a signal generated by piezoelectric effect thereof. A structure of a high-temperature piezoelectric element, comprises polarized piezoelectric material (1), wherein the coating of metallic conductive slurry (2) is removed from the surfaces of the polarized piezoelectric material (1) and the surfaces of the polarized piezoelectric material (1) is connected to electrode lead wires (3) to output a signal generated by piezoelectric effect thereof. By removing the traditional coating of slurry for electrode, it is avoided that the output resistance of the piezoelectric element is reduced because of the high temperature diffusion of electrode material at a high temperature, and the thermal performance of the piezoelectric element is improved. By adding diamond or graphite coating as electrode, the sensitivity of outputting charges of the piezoelectric element is improved.

The structure of a mother piezoelectric element allows a polarization process to be performed on the mother body before the individual piezoelectric elements are cut from the mother piezoelectric element. The mother piezoelectric element includes a plurality of first internal electrodes which are provided on at least one first surface and a plurality of second internal electrodes which are provided on at least one second surface. Each of the first and second internal electrodes is led out to any of first to fourth side surfaces of a mother piezoelectric body. The plurality of first internal electrodes are electrically connected to each other on a first surface and the plurality of second internal electrodes are electrical connected to each other on a second surface. All the first internal electrodes in the mother piezoelectric body are electrically connected to each other, and all the second internal electrodes in the mother piezoelectric body are electrically connected to each other.

The present invention discloses a transparent piezoelectric single crystal with high piezoelectricity and a preparation method thereof, a photoacoustic transducer, a transparent actuator and an optical-electro-mechanical coupling device prepared from the transparent piezoelectric single crystal with high piezoelectricity. The piezoelectric single crystal is a binary/ternary relaxor-PT based ferroelectric crystal poled by an AC electric field, and has ultrahigh piezoelectricity and excellent transparency.