An actuator device comprises an electroactive or photoactive polymer arrangement having an effective length over which expansion or contraction is induced by actuation. The effective length is greater than the maximum linear physical dimension of the space occupied by the polymer arrangement. In this way, a compact design is provided which can support a large actuation displacement.

An acoustic wave sensor may include: a continuous membrane deflectable by acoustic waves to be detected, and a piezoelectric layer provided on the membrane and including a plurality of piezoelectric layer portions respectively equipped with at least two individual electric contact structures configured to electrically connect the respective piezoelectric layer portions. Electric contact structures associated with different piezoelectric layer portions may be separated from each other.

Provided is an actuator including: a stack including: an elastomer layer; and an elastic electrode disposed on each surface of the elastomer layer, in which the stack is subjected to a pre-strain of 50% or more at least in one direction.

A transducer includes a housing, and a piezoelectric element that is disposed inside the housing and that has a porous film. The piezoelectric element is bent or curved.

A cylindrical secondary battery includes a jelly-roll type electrode assembly having a structure in which a long sheet type positive electrode and a long sheet type negative electrode are wound with a separator interposed between the positive electrode and the negative electrode. The cylindrical secondary battery also includes a cylindrical battery case configured to receive the jelly-roll type electrode assembly, and a piezoelectric element configured to generate electrical energy due to the volumetric expansion of the jelly-roll type electrode assembly caused by charging and discharging the jelly-roll type electrode assembly.

The present application relates to stacked piezoelectric composites comprising piezoelectric structures. Suitably, the composites are useful as tissue-stimulating implants, including spinal fusion implants. The present application also relates to methods of making stacked piezoelectric composites.

A preparation method for a piezoelectric fiber is provided including a piezoelectric functional layer and an insulating layer coated on the piezoelectric functional layer. The piezoelectric functional layer includes a piezoelectric composite layer of a spiral winding structure, and the piezoelectric composite layer includes a first piezoelectric layer, a conductive layer and a second piezoelectric layer that are sequentially stacked. The preparation method includes taking one end of the piezoelectric composite layer as a winding axis, winding the piezoelectric composite layer in a direction perpendicular to the winding axis to form the piezoelectric functional layer, wherein turns of winding the piezoelectric composite layer are greater than 5, coating the piezoelectric functional layer with the insulating layer, and vacuum heating to consolidate, to prepare a preform rod.

Provided is a piezoelectric laminate element that outputs a fixed output voltage even in response to a static load for which an output voltage could not be obtained using a conventional piezoelectric element. A piezoelectric laminate body in which a plurality of piezoelectric polymer film layers consisting of film such as polylactic acid film that exhibits piezoelectricity in the planar direction are laminated is used as a piezoelectric laminate element. The piezoelectric laminate body is given a cylindrical shape, rounded rectangle shape, or other partially curved shape. The output voltage follows the increase and decrease of the applied load, and if a fixed load is continuously applied, a fixed output voltage is continuously output, and a piezoelectric laminate element is obtained that outputs a fixed output voltage even if a load is static.

An actuator having good interlayer adhesion at a lamination interface, good conductivity of an electrode layer, and good smoothness of the electrode layer is provided. The actuator includes a plurality of elastomer layers and a plurality of electrode layers, and the elastomer layers and electrode layers are alternately laminated. The electrode layer contains carbon black, a content of the carbon black in the electrode layer is 10% by mass or more and 20% by mass or less, and a specific surface area of the carbon black is 380 g/m.sup.2 or more and 800 m.sup.2/g or less.

Devices and methods are provided for harvesting kinetic energy. The devices can include a plurality of dielectric elastomeric membranes, a rigid connector rod, and a mountable support base. Membrane layers have a funnel-shape with a narrow opening portion and a wide perimeter portion. Membrane layers are adjacent to other membrane layers having an opposite orientation defined by the narrow opening portion and the wide perimeter portion. The narrow opening portions are coupled to a first end portion of the connector rod. The wide perimeter portions are fixed in relation to the support base. Application of linear force at a second end portion of the connector rod in a first direction causes at least a first membrane layer to stretch. Application of the force in a second direction opposite to the first direction causes at least a second membrane layer adjacent to the first membrane layer to stretch.