The present technology relates to an audio device and a driving method thereof, and a display device which are configured to make it possible to obtain sufficient sound pressure level in a wider frequency band. The audio device includes: a diaphragm; an electrodynamic vibrator that vibrates the diaphragm to output sound; and a piezoelectric vibrator that vibrates the diaphragm to output sound. The present technology can be applied to the display device.

Piezoelectric materials are utilized in shear mode deformation to excite longitudinal flexural bending electromechanical motion in a transducer. A single transducer stack comprising a plurality of shear mode piezoelectric material elements are arranged to create a flexural bender bar which can be used for electroacoustic applications. The transducer stack is configured such that adjacent piezoelectric elements have opposite shear mode deformation. Electrodes for positive and negative voltage excitation are applied to parallel faces of the piezoelectric elements. Application of a voltage difference between the electrodes causes the piezoelectric elements to undergo shear strain, wherein one half of the transducer stack expands into tension and the other half contracts into compression, thus inducing longitudinal flexural bending electromechanical motion. Enclosed embodiments provide support structures for utilization of piezoelectric shear mode induced longitudinal flexural bending electromechanical motion.

Disclosed in the present invention are an antibacterial electric toothbrush based on a pulsed ultrasonic piezoelectric response principle, and an antibacterial method. The electric toothbrush in the present invention comprises a toothbrush head and a driving mechanism for driving the toothbrush head to vibrate, wherein the driving mechanism is configured to generate low-intensity pulsed ultrasonic waves, and the toothbrush head is provided with piezoelectric bristles and enhances the electric responsiveness of the piezoelectric bristles by means of ultrasonic vibration, such that a good antibacterial effect is achieved. The provided electric toothbrush can not only effectively inhibit the growth of bacteria on a standing toothbrush head, but also has improved antibacterial activity during a tooth-brushing operation process, such that dental plaque can be effectively inhibited, and oral diseases, such as periodontitis, can be effectively prevented.

An acoustic energy tool comprising a crystal for generating acoustic energy when a volage is applied to the crystal, and a resonator. The resonator has a solid outer structure with the crystal being attached to the solid outer structure, with the resonator being comprised of a material that transmits the acoustic energy through the resonator. The tool includes a curved surface that focuses the acoustic energy being transmitted through the resonator and a fluid passageway that extends through the resonator for allowing a fluid to flow through the resonator. The acoustic energy being focused by the curved surface is concentrated in the fluid passageway so that it causes cavitation of the fluid in at least part of the fluid passageway. The cavitation of the fluid is used to break up clumps that form in the fluid or to generate reactive oxygen species.

A hollow three-dimensional piezoelectric device of conformable tape-casted textured ceramic material is formed sheets that are pre-cut in preselected patterns and smoothly conformably stacked in layers on a mold defining the desired three-dimensional shape. The final stack is isostatically compressed into the shape of the mold. The predetermined cut patterns are selectively configured to facilitate the smoothly conformable placement and stacking of the layers over the entire mold surface. The cut pattern may be three, four, or more convex circular triangles extending radially from a common point and that fit together to form a hemisphere when conformed to the mold. Each layer may comprise one or a plurality of tape-casted sheets, and the cut patterns in successive layers may be gradually dimensionally increased to accommodate the layer-to-layer increase in the diameter (i.e., thickness) of the stack.

Provided are a driver unit of a headphone, in which, in a case where a driver unit including a piezoelectric film having a formed curved portion is applied to the headphone, deformation of the curved portion of the piezoelectric film in a case of wearing the headphone can be suppressed, and deterioration in sound quality can be suppressed; and a headphone. The driver unit includes a piezoelectric film which has a piezoelectric layer consisting of a polymer-based piezoelectric composite material containing piezoelectric particles in a matrix containing a polymer material and electrode layers provided on both surfaces of the piezoelectric layer, and a perforated plate having at least one through-hole, in which the piezoelectric film has a curved portion which is formed to protrude to one main surface side and to be recessed to the other main surface side, the perforated plate is laminated on a concave surface side of the curved portion of the piezoelectric film, and in the through-hole, a first air chamber defined by the concave surface of the piezoelectric film and the perforated plate communicates with an outside.