A modular array includes modular array includes one or more array modules. Each array module includes one or more transducer arrays, where each of the one or more transducer arrays includes a plurality of piezoelectric elements; a conducting interposer arranged and configured to provide acoustic absorbing backing for the one or more transducer arrays; and one or more Application Specific Integrated Circuits (ASICs). The conducting interposer and the one or more ASICs are in electrical contact with each other at a first direct electrical interface. Additionally, the conducting interposer and the one or more transducer arrays are in electrical contact with each other at a second direct electrical interface.

Some embodiments of the invention relate to an applicator for applying ultrasound energy to a tissue volume, comprising: an array comprising a plurality of ultrasound transducers, the transducers arranged side by side, the transducers configured to emit unfocused ultrasound energy suitable to thermally damage at least a portion of the tissue volume, each of the transducers comprising a coating thin enough so as not to substantially affect heat transfer via the coating to the tissue; and a cooling module configured to apply cooling via the transducers to prevent overheating of a surface of the tissue volume being contacted by the transducers.

The present disclosure provides a composite electrode, an acoustic sensor using the composite electrode, and a manufacturing method of the composite electrode. The composite electrode includes a conductive layer, and a semiconductor high-molecular polymer layer formed on the conductive layer. The semiconductor high-molecular polymer layer has a three-dimensional mesh structure. The acoustic sensor includes a base; the above-mentioned composite electrode formed on the base; an organic layer formed on the composite electrode; and a top electrode formed on the organic layer.

Semiconductor strain gages fabricated on Silicon-on-insulator (SOI) material, and the method of making them. Force sensing elements are uniformly batch-fabricated at wafer level and singulated individually by a wire bonding method. In another method, they are singulated by plucking them off the wafer from their attachment site.

Described herein are aspects of a three-dimensional (3D) piezoelectric structure that can be composed of a 3D periodic microlattice that can be composed of a piezoelectric composite material, wherein the 3D periodic microlattice can include a plurality of interconnected 3D node units capable of generating a piezoelectric response upon application of a stress to the 3D periodic microlattice, and wherein the plurality of interconnected 3D node units can form a tailored piezoelectric tensor space. Also described herein are systems that can include one or more of the 3D piezoelectric structures described herein. Also described herein are methods of making and using the 3D piezoelectric structures described herein.

Embodiments of the disclosure are generally directed to systems and methods for switchable electroactive devices for head-mounted displays (HMDs). In particular, a method may include (1) applying an electric field to an electroactive element of an electroactive device via electrodes of the electroactive device that are electrically coupled to the electroactive element to compress the electroactive element, which comprises a polymer material defining nanovoids, such that an average size of the nanovoids is decreased and a density of the nanovoids is increased in the electroactive element, wherein the electroactive device is positioned at a distance from a user's eye, and (2) emitting image light from an emissive device positioned such that at least a portion of the image light is incident on a surface of the electroactive device facing the user's eye.

The disclosed technology generally relates to quartz crystal devices and more particularly to quartz crystal devices configured to vibrate in torsional mode. In one aspect, a quartz crystal device configured for temperature sensing comprises a fork-shaped quartz crystal comprising a pair of elongate tines laterally extending from a base region in a horizontal lengthwise direction of the fork-shaped quartz crystal. Each of the tines has formed on one or both of opposing sides thereof a vertically protruding line structure laterally elongated in the horizontal lengthwise direction. The quartz crystal device further comprises a first electrode and a second electrode formed on the one or both of the opposing sides of each of the tines and configured such that, when an electrical bias is applied between the first and second electrodes, the fork-shaped quartz crystal vibrates in a torsional mode in which each of the tines twists about a respective axis extending in the horizontal lengthwise direction.

An example device includes a nanovoided polymer element, which may be located at least in part between the electrodes. In some examples, the nanovoided polymer element may include anisotropic voids, including a gas, and separated from each other by polymer walls. The device may be an electroactive device, such as an actuator having a response time for a transition between actuation states. The gas may have a characteristic diffusion time (e.g., to diffuse half the mean wall thickness through the polymer walls) that is less than the response time. The nanovoids may be sufficiently small (e.g., below 1 micron in diameter or an analogous dimension), and/or the polymer walls may be sufficiently thin, such that the gas interchange between gas in the voids and gas absorbed by the polymer walls may occur faster than the response time, and in some examples, effectively instantaneously.

An energy harvester comprises: converter capable of converting a variation of energy to be harvested into a potential difference between two electric terminals by accumulating charges; the converter including a stack of layers with at least one first layer made of a piezoelectric material; a collection circuit connected to the terminals and comprising a switch, the collection circuit being configured to harvest the charges when the switch is in a closed state; the converter being able to emit acoustic vibrations in an audible frequency band when the collection circuit harvests the charges; the energy harvester further comprises a control circuit configured to control a plurality of closing-opening sequences (S.sub.FO) of the switch, when the potential difference reaches a defined threshold, so as to harvest the charges through a plurality of partial discharges of the converter and to limit the stress deviation experienced by the first layer during each discharge.

A cooling system and method for using the cooling system are described. The cooling system includes a plurality of individual piezoelectric cooling elements spatially arranged in an array extending in at least two dimensions, a communications interface and driving circuitry. The communications interface is associated with the individual piezoelectric cooling elements such that selected individual piezoelectric cooling elements within the array can be activated based at least in part on heat energy generated in the vicinity of the selected individual piezoelectric cooling elements. The driving circuitry is associated with the individual piezoelectric cooling elements and is configured to drive the selected individual piezoelectric cooling elements.