Provided is an electroacoustic converter film including: a polymeric composite piezoelectric body having piezoelectric particles dispersed in a viscoelastic matrix which is formed of a polymer material exhibiting viscoelasticity at ordinary temperatures; thin film electrodes formed on both sides of the polymeric composite piezoelectric body; and protective layers formed on surfaces of the thin film electrodes. The electroacoustic converter film serves as a speaker capable of being integrated with a flexible display without impairing lightweightness or flexibility, and has considerable frequency dispersion in the storage modulus and also has a local maximum of the loss tangent around ordinary temperatures. A flexible display, a vocal cord microphone and a musical instrument sensor, in each of which the electroacoustic converter film is used, are also provided.

A piezoelectric sensor, a manufacturing method thereof and an electronic device are provided. The piezoelectric sensor includes a substrate, an active layer, the active layer being disposed at a side of the substrate: a first electrode, the first electrode being disposed at a side of the active laver a wav from the substrate, and the first electrode including a plurality of sub-electrodes disposed at intervals: a piezoelectric layer, the piezoelectric layer being disposed at a side of the first electrode away from the active layer; and a second electrode, the second electrode being disposed at a side of the piezoelectric layer away from the first electrode. The active layer is configured to be capable of switching between an insulating state and a conducting state, and in the conducting state the active layer is capable of conducting the plurality of sub-electrodes.

A bender beam actuator includes a first layer of piezoelectric material and a second layer of piezoelectric material overlying a portion of the first layer of piezoelectric material, where a length of the first layer of piezoelectric material is at least 2% greater than a length of the second layer of piezoelectric material.

Provided are an electroacoustic transduction film capable of reproducing a sound with a sufficient sound volume at a high conversion efficiency, a manufacturing method thereof, an electroacoustic transducer, a flexible display, a vocal cord microphone, and a sensor for a musical instrument. The electroacoustic transduction film includes: a polymer composite piezoelectric body in which piezoelectric body particles are dispersed in a viscoelastic matrix formed of a polymer material having viscoelasticity at a normal temperature; two thin film electrodes laminated on both surfaces of the polymer composite piezoelectric body; and two protective layers respectively laminated on the two thin film electrodes, in which an intensity ratio α.sub.1=(002) plane peak intensity/((002) plane peak intensity+(200) plane peak intensity) between a (002) plane peak intensity and a (200) plane peak intensity derived from the piezoelectric body particles in a case where the polymer composite piezoelectric body is evaluated by an X-ray diffraction method is more than or equal to 0.6 and less than 1.

Provided is a method of manufacturing an oscillator, including: arranging an electrode on a piezoelectric ceramics free from being subjected to polarization treatment, to thereby provide a piezoelectric element; bonding the piezoelectric element and a diaphragm to each other at a temperature T1; bonding the piezoelectric element and a power supply member to each other at a temperature T2; and subjecting the piezoelectric ceramics to polarization treatment at a temperature T3, in which the temperature T1, the temperature T2, and the temperature T3 satisfy a relationship T1>T3 and a relationship T2>T3.

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/m.sup.2 or more.

A poling apparatus for poling a polymer thin film formed on a workpiece carried by a workpiece carrier. The workpiece has multiple grounding electrodes, grounding pads located at its edges, and a polymer thin film including multiple areas each covering only one grounding electrode. The poling apparatus includes, in a poling chamber, a poling source generating a plasma, a shadow mask below the poling source, and a Z-elevator to raise the workpiece carrier toward the shadow mask and poling source. When the workpiece in the workpiece carrier is raised to contact the underside of the shadow mask, multiple openings of the shadow mask expose only the corresponding multiple thin film areas of the workpiece to the plasma; meanwhile, conductive grounding terminals on the underside of the shadow mask electrically connect the grounding pads of the workpiece with carrier electrodes on the workpiece carrier, to ground the workpiece.

A PZT microactuator such as for a hard disk drive has a restraining layer bonded on its side that is opposite the side on which the PZT is mounted. The restraining layer comprises a stiff and resilient material such as stainless steel. The restraining layer can cover most or all of the top of the PZT, with an electrical connection being made to the PZT where it is not covered by the restraining layer. The restraining layer reduces bending of the PZT as mounted and hence increases effective stroke length, or reverses the sign of the bending which increases the effective stroke length of the PZT even further. The restraining layer can be one or more active layers of PZT material that act in the opposite direction as the main PZT layer. The restraining layer(s) may be thinner than the main PZT layer.

An electromechanical transducer includes an electromechanical transducer film of laminated layers including a perovskite-type complex oxide represented by a general formula of ABO.sub.3; and a pair of electrodes opposed to each other with the electromechanical transducer film interposed between the pair of electrodes. In the general formula of ABO.sub.3, A includes Pb and B includes Zr and Ti. A variable ratio ΔPb of Pb, determined by Pb(max)−Pb(min), is 6% or less and a variable ratio ΔZr of Zr, determined by Zr(max)−Zr(min), is 9% or less, where an atomic weight ratio of Pb in the electromechanical transducer film is denoted by Pb/B, an atomic weight ratio of Zr in the electromechanical transducer film is denoted by Zr/B, a maximum value and a minimum value of the atomic weight ratio of Pb in a film thickness direction of the electromechanical transducer film are denoted by Pb(max) and Pb(min), respectively, and a maximum value and a minimum value of the atomic weight ratio of Zr in the film thickness direction of the electromechanical transducer film are denoted by Zr(max) and Zr(min), respectively.

An apparatus 10 for poling piezoelectric material includes a platen 22 which holds a sample 20 of piezoelectric material to be poled and a stage 30 to which the platen is mounted. The stage 30 is arranged to selectively move the platen 22 and thereby the sample 20 which the platen 22 holds. The platen 22 is movable by the stage 30 selectively between a first position and a second position. A corona source 40 generates a corona to which the sample 20 is exposed when the platen 22 is moved to the first position by the stage 30. An electrostatic voltmeter 60 having a probe 62 measures a surface potential of the sample 20 when the platen 22 is moved to the second position by the stage 30.