A system and method for detecting an anomaly in a structure using an adaptive filter to compensate for variations in piezoelectric transducer performance due to environmental factors such as temperature. A first voltage signal having a first amplitude is sent to a reference piezoelectric actuator. Thereafter, a first reference voltage signal is received from a reference piezoelectric receiver which is acoustically coupled to detect the guided wave generated by the reference piezoelectric actuator. A second amplitude is determined using an optimization algorithm of an adaptive filter to compensate for nonlinear behavior of the reference piezoelectric actuator and receiver based on the first reference voltage signal. Then the adaptive filter sends a second voltage signal having the second amplitude to the reference and test piezoelectric actuators. Reference and test voltage signals are received from the reference and test piezoelectric receivers in response to the second voltage signal. A difference voltage signal representing differences between the reference and test voltage signals received is then recorded.

A method for preparing a polymer composite material is provided. The method includes steps of mixing and heat-treating a first polymer, a second polymer, and a third polymer to obtain a first mixture, adding a light-transmitting material to the first mixture to obtain a second mixture, adding a nano material to the second mixture to obtain a third mixture, performing subsequent processing on the uniformly mixed third mixture to obtain the polymer composite material. The polymer composite material is configured to replace conventional protective glass in ultrasonic fingerprint recognition technology, and to improve accuracy of fingerprint recognition.

Disclosed embodiments include illustrative piezoelectric element array assemblies, methods of fabricating a piezoelectric element array assembly, and systems and methods for shearing cellular material. Given by way of non-limiting example, an illustrative piezoelectric element array assembly includes at least one piezoelectric element configured to produce ultrasound energy responsive to amplified driving pulses. A lens layer is bonded to the at least one piezoelectric element. The lens layer has a plurality of lenses formed therein that are configured to focus ultrasound energy created by single ones of the at least one piezoelectric element into a plurality of wells of a microplate disposable in ultrasonic communication with the lens layer, wherein more than one of the plurality of lenses overlie single ones of the at least one piezoelectric element.

Acoustic forces in an acoustic field can be increased via introduction of “seeding particles” with higher or similar contrast factor and/or size relative to the particles targeted for retention in the acoustic field. This feature may be implemented in an acoustic concentration device or an acoustic separation device. Increases in acoustic forces lead to better particle retention and can permit increased flow rates through an acoustic particle processing device.

Disclosed is an electronic device. The electronic device according to an embodiment may include an ultrasonic sensor and a processor electrically connected to the ultrasonic sensor. The processor may be configured to obtain a noise signal at a periphery of the electronic device, via the ultrasonic sensor, to determine an attribute of a first ultrasonic signal oscillated by the ultrasonic sensor, based on the obtained noise signal, and to obtain fingerprint information based on the second ultrasonic signal obtained via the ultrasonic sensor and the determined attribute. Moreover, various embodiment found through the disclosure are possible.

Some disclosed implementations include an ultrasonic sensor stack and an acoustic resonator. The acoustic resonator may be configured to enhance ultrasonic waves transmitted by the ultrasonic sensor stack in an ultrasonic frequency range that is suitable for ultrasonic fingerprint sensors. In some examples, the acoustic resonator may include one or more low-impedance layers residing between a first higher-impedance layer and a second higher-impedance layer. Each of the one or more low-impedance layers may have a lower acoustic impedance than an acoustic impedance of the first higher-impedance layer or an acoustic impedance of the second higher-impedance layer. At least one low-impedance layer may have a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator. The peak frequency may be within a frequency range from 1 MHz. to 20 MHz.

An ultrasonic transducer is described, including a piezoelectric element, a fluid medium contact layer, a matching layer between the piezoelectric element and the fluid medium contact layer, and a backing layer. Ultrasound sensor devices utilising the ultrasonic transducer are also described, for use in systems for analysing a fluid such as milk.

An electromagnetic actuator including an attractor to exert a magnetic attractive force in one side in a first direction, a frame, and a lever. The frame includes a frame body fixed to the attractor, and a support on an oblique-direction side relative to the attractor. The lever includes a fulcrum portion pivotally supported by the support, a first displaceable portion arranged on the other side in the second direction relative to the fulcrum portion and on the other side in the first direction relative to the attractor and magnetically attractable by the attractor to be displaced to the one side in the first direction, and a second displaceable portion arranged on the one side in the first direction relative to the fulcrum portion and on the one side in the second direction relative to the attractor and/or the frame and displaceable away from the attractor and/or the frame by the pivot of the lever.

An acoustic imaging system coupled to an acoustic medium to define an imaging surface. The acoustic imaging system includes an array of piezoelectric acoustic transducers formed at least in part from a thin-film piezoelectric material, such as PVDF. The array is coupled to the acoustic medium opposite the imaging surface and formed using a thin-film manufacturing process over an application-specific integrated circuit that, in turn, is configured to leverage the array of piezoelectric actuators to generate an image of an object at least partially wetting to the imaging surface.

A piezoelectric micromachined ultrasound transducer (PMUT) device may include a plurality of layers including a structural layer, a piezoelectric layer, and electrode layers located on opposite sides of the piezoelectric layer. Conductive barrier layers may be located between the piezoelectric layer and the electrodes to the prevent diffusion of the piezoelectric layer into the electrode layers.