An apparatus includes a vibration member, a housing at a rear surface of the vibration member, a connection member between the vibration member and the housing, and a vibration apparatus configured to vibrate the vibration member, the vibration member includes at least one flat portion and at least one flexural portion adjacent to the at least one flat portion.

An apparatus may include a vibration member and a vibration apparatus provided at a rear surface of the vibration member to vibrate the vibration member. The vibration apparatus may include at least one or more first vibration portions and a plurality of second vibration portions different from the at least one or more first vibration portions. The at least one or more first vibration portions may be at a periphery of, or may be adjacent to, the plurality of second vibration portions.

A sound generator for a display device, including: a first vibration generation unit having a first electrode and a second electrode; a second vibration generation unit having a third electrode and a fourth electrode; and a vibration layer including: a first sub-vibration layer disposed between the first electrode and the second electrode; and a second sub-vibration layer disposed between the third electrode and the fourth electrode, wherein the first vibration generation unit is configured to contract and expand the first sub-vibration layer based on a first driving voltage applied to the first electrode and a second driving voltage applied to the second electrode, and wherein the second vibration generation unit is configured to contract and expand the second sub-vibration layer based on a third driving voltage applied to the third electrode and a fourth driving voltage applied to the fourth electrode.

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.

An ultrasonic transducer includes a carrier with a first surface and a second surface which are opposite to each other, a piezoceramic element attached on the first surface of the carrier, a first acoustic matching layer with a third surface and a fourth surface which are opposite to each other, the third surface is attached on the second surface of the carrier, wherein the first acoustic matching layer includes a mesh with openings, and the thickness of first acoustic matching layer is smaller than ¼ wavelength of an ultrasonic wave emitted by the piezoceramic element in the first acoustic matching layer in an operating frequency, and a total area of the openings of mesh is larger than 30% area of the third surface of first acoustic matching layer, and a second acoustic matching layer disposed on the fourth surface of the first acoustic matching layer.

A flexible vibration module is disclosed. The flexible vibration module includes a piezoelectric composite layer, including: a plurality of piezoelectric portions each having a piezoelectric characteristic, where at least two of the plurality of piezoelectric portions have different sizes; and a flexible portion between the plurality of piezoelectric portions.

Some embodiments relate to an energy transduction device or apparatus. An example device or apparatus includes: a piezoelectric transducer; electrical conductors electrically coupled to the piezoelectric transducer; and an axially aligned magnet assembly arranged to apply static compressive force to the piezoelectric transducer, the magnet assembly being coupled to a base at one end and having a free opposite end. The magnet assembly is coaxial with the piezoelectric transducer and at least part of the magnet assembly is concentric with the piezoelectric transducer. The magnet assembly defines a gap between axially adjacent parts of the magnet assembly, wherein the gap is dimensioned to be sufficiently small that the magnet assembly applies a static compressive force to the piezoelectric transducer while being sufficiently large to allow for axial movement of the piezoelectric transducer without closing the gap.

An object of the present invention is to provide a piezoelectric film capable of realizing an electroacoustic conversion film or the like in which the durability is high and a sufficient sound pressure with respect to an input operating voltage is obtained. The object is achieved by providing a piezoelectric film including a polymer-based piezoelectric composite material which contains piezoelectric particles in a matrix containing a polymer material, and electrode layers which are provided on both surfaces of the polymer-based piezoelectric composite material, in which in a case where a cross section of the film in a thickness direction is observed with a scanning electron microscope, the polymer-based piezoelectric composite material is divided into ten equal regions in the thickness direction, area ratios of the piezoelectric particles in two most distant regions are measured, and the area ratio of the piezoelectric particles in the region with a lower area ratio is set as 1, the area ratio of the piezoelectric particles in the region with a higher area ratio is 1.2 or greater.

An apparatus may include a vibration member, a supporting member at a rear surface of the vibration member, and a vibration apparatus. The vibration apparatus may be disposed at the supporting member and may include a curved shape.

An apparatus may include a vibration member, a rear cover at a rear surface of the vibration member, a first vibration device at a first rear region of the rear cover, and a second vibration device at a second rear region of the rear cover. The first vibration device may overlap at least one of a horizontal region and a middle region of the rear cover. The second vibration device may overlap a periphery region or a middle region of the rear cover.