A polymer thin film includes polyvinylidene fluoride (PVDF) and is characterized by a Young's modulus along an in-plane dimension of at least 4 GPa, an electromechanical coupling factor (k.sub.31) of at least 0.1 at room temperature. A method of manufacturing such a polymer thin film may include forming a polymer composition into a polymer thin film, applying a tensile stress to the polymer thin film along at least one in-plane direction and in an amount effective to induce a stretch ratio of at least approximately 5 in the polymer thin film, and applying an electric field across a thickness dimension of the polymer thin film. Annealing and poling steps may separately or simultaneously accompany and/or follow the act of stretching of the polymer thin film.

A resonant member of a MEMS resonator oscillates in a mechanical resonance mode that produces non-uniform regional stresses such that a first level of mechanical stress in a first region of the resonant member is higher than a second level of mechanical stress in a second region of the resonant member. A plurality of openings within a surface of the resonant member are disposed more densely within the first region than the second region and at least partly filled with a compensating material that reduces temperature dependence of the resonant frequency corresponding to the mechanical resonance mode.

The present invention provides novel methods for poling piezoelectric materials, e.g., collagen, which are carried out in the absence of liquid media and at a relatively low temperature. The present invention also provides electroactive scaffolds comprising poled collagen for promoting cell growth and differentiation.

A piezoelectric stack, including: a substrate; an electrode film; and a piezoelectric film comprising an alkali niobium oxide of a perovskite structure represented by a composition formula of (K.sub.1-xNa.sub.x)NbO.sub.3 (0<x<1), wherein an average light transmittance through the piezoelectric film in a wavelength region of visible light and near-infrared ray is 65% or more.

[Object]

An object of the present invention is to provide a method for manufacturing an oxide single crystal substrate having less dispersion in characteristics within the substrate surface.

[Means to solve the Problems]

In the manufacture method of the present invention, a powder containing a Li compound is dispersed in a medium to form a slurry, and heat is applied while the slurry is in contact with the surface of the oxide single crystal substrate, so as to diffuse Li into the substrate from the surface thereof to effect a modification of the substrate; or after the slurry is brought into contact with the surface of the oxide single crystal substrate, the oxide single crystal substrate is buried in a powder containing the Li compound, and heat is applied to effect the diffusion of Li in the substrate from the surface thereof whereby a modification of the substrate occurs.

A method for manufacturing a piezoelectric device that includes a substrate, a piezoelectric layer directly or indirectly supported by the substrate and arranged above the substrate, a heater, and a heater electrode for driving the heater. Moreover, the method includes forming the piezoelectric layer, the heater, and the heater electrode and subjecting the piezoelectric device to heat treatment with heat generated from the heater by driving the heater by feeding electric power to the heater electrode.

A method for manufacturing a piezoelectric device that includes a substrate and a vibration portion that can include a membrane or a beam that is directly or indirectly supported by the substrate and arranged above the substrate. Moreover, the vibration portion includes a piezoelectric layer and the method includes forming the vibration portion and adjusting a resonance frequency of the vibration portion by locally subjecting a region including the vibration portion to heat treatment.

A piezoelectric vibration member that includes a substrate having a main surface on or in which a piezoelectric vibration member is mounted, a lid having a recess that is open so as to face the main surface and which includes a flange portion that projects outward from an opening edge of the recess, and a bonding layer that bonds the substrate and the lid together so as to hermetically seal the piezoelectric vibrator in a space between the recess and the main surface. The surface roughness of a side surface of the flange portion is greater than the surface roughness of the surface of the recess, and the bonding layer extends from the main surface of the substrate to the side surface of the flange portion.

The present invention provides electroactive polymer (“EAP”) transducers having improved properties. This improvement is achieved without decreasing film thickness, or by using high dielectric constant and high field, so that this approach does not adversely affect the reliability and physical properties of the resultant dielectric films. Mobile electrically active additives are added to the electrode formulation which significantly improve the performance of electroactive polymer transducers. Such additives do not need to be ionic. These electrically active additives can enable higher performance devices, smaller devices using less active area, lower voltage/power operation, and combinations of these enhancements.

A polymeric piezoelectric material, comprising at least two regions: a region H, which is an oriented polymeric piezoelectric region that includes an optically active helical chiral polymer (A) having a weight average molecular weight of from 50,000 to 1,000,000, the region H having a crystallinity of from 20% to 80% and having a standardized molecular orientation-of from 3.5 to 15.0; and a region L, which is a low orientation region that includes the optically active helical chiral polymer (A) having a weight average molecular weight of from 50,000 to 1,000,000, the region L being present near at least part of an end portion of the region H, having an average width when viewed from a normal direction with respect to the principal plane of the region H of from 10 μm to 300 μm, and having a retardation is 100 nm or less.