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.

A piezoelectric device includes a first piezoelectric sensor having a first inner conductor, a first piezoelectric body, and a first outer conductor, a second piezoelectric sensor having a second inner conductor, a second piezoelectric body, and a second outer conductor, and a differential signal forming unit having a pair of differential input terminals. When an external force acts on the first piezoelectric body, the first piezoelectric sensor generates a first voltage, and the second piezoelectric sensor generates a second voltage having a voltage different in polarity from the first voltage. The first inner conductor is electrically connected to one differential input terminal. The second inner conductor is electrically connected to the other differential input terminal. The differential signal forming unit forms a differential signal based on a first signal input to the one differential input terminal and a second signal input to the other differential input terminal.

A liquid ejecting head includes a pressure compartment forming substrate, a piezoelectric actuator, a sealing plate, and a flexible wiring board. A pressure compartment is formed in the pressure compartment forming substrate. The piezoelectric actuator is disposed over the pressure compartment. The sealing plate has an opening going from a first surface, which is farther from the pressure compartment, to a second surface, which is closer to the pressure compartment. The sealing plate is configured to cover the piezoelectric actuator located in a first direction with respect to the opening. The flexible wiring board is inserted in the opening and is electrically coupled to the piezoelectric actuator. A first opening width of the opening at the first surface in the first direction is greater than a second opening width of the opening at the second surface in the first direction.

Certain examples disclose and describe apparatus and methods to provide fast response active clearance system with piezoelectric actuator in axial, axial/radial combined, and circumferential directions. In some examples, an apparatus includes an actuator to control clearance between a blade and at least one of a shroud or a hanger, the actuator including a multilayer stack of material, and wherein the actuator is outside a case. The apparatus further includes a rod coupled to the actuator and the at least one of the shroud or the hanger through an opening in the case, the rod to move the at least one of the shroud or the hanger in a radial direction based on axial movement of the multilayer stack of material.

The present disclosure relates to circuitry for driving a piezoelectric transducer. The circuitry may be implemented as an integrated circuit and comprises driver circuitry configured to supply a drive signal to the piezoelectric transducer to cause the transducer to generate an output signal and active inductor circuitry configured to be coupled with the piezoelectric transducer. The active inductor circuitry may be tuneable to adjust a frequency characteristic of the output signal.

A system for cooling a mobile phone and method for using the system are described. The system includes an active piezoelectric cooling system, a controller and an interface. The active piezoelectric cooling system is configured to be disposed in a rear portion of the mobile phone distal from a front screen of the mobile phone. The controller is configured to activate the active piezoelectric cooling system in response to heat generated by heat-generating structures of the mobile phone. The interface is configured to receive power from a mobile phone power source when the active piezoelectric cooling system is activated.

A system for cooling a mobile phone and method for using the system are described. The system includes an active piezoelectric cooling system, a controller and an interface. The active piezoelectric cooling system is configured to be disposed in a rear portion of the mobile phone distal from a front screen of the mobile phone. The controller is configured to activate the active piezoelectric cooling system in response to heat generated by heat-generating structures of the mobile phone. The interface is configured to receive power from a mobile phone power source when the active piezoelectric cooling system is activated.

This application relates to methods and apparatus for driving a transducer with switching drivers. A driver circuit has first and second switching drivers for driving the transducer in a bridge-tied-load configuration, each of the switching drivers having a respective output stage for controllably switching the respective driver output node between high and low switching voltages with a controlled duty cycle. Each of switching drivers is operable in a plurality of different driver modes, wherein the switching voltages are different in said different driver modes. A controller controls the driver mode of operation and the duty cycle of the switching drivers based on the input signal. The controller is configured to control the duty cycles of the first and second switching drivers within defined minimum and maximum limits of duty cycles; and to transition between driver modes of operation when the duty cycle of one of the switching drivers reaches a duty cycle limit.

A display apparatus includes: a display panel configured to display an image, and at least one vibration module on a rear surface of the display panel, the at least one vibration module including a piezoelectric composite layer including a plurality of sub-modules configured to vibrate the display panel, each of the plurality of sub-modules including: a plurality of first portions including a piezoelectric characteristic, and a plurality of second portions having flexibility, each of the plurality of second portions being between a respective pair of the plurality first portions, wherein the plurality of first portions in the respective sub-modules are arranged in a same direction or are partially arranged in different directions.

A display apparatus includes: a display panel configured to display an image, and at least one vibration module on a rear surface of the display panel, the at least one vibration module including a piezoelectric composite layer including a plurality of sub-modules configured to vibrate the display panel, each of the plurality of sub-modules including: a plurality of first portions including a piezoelectric characteristic, and a plurality of second portions having flexibility, each of the plurality of second portions being between a respective pair of the plurality first portions, wherein the plurality of first portions in the respective sub-modules are arranged in a same direction or are partially arranged in different directions.