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.

An acoustic device (100) comprises an array of acoustic membranes (1, 2, 3, 4) formed on a foil (10). Each of the acoustic membranes (1, 2, 3, 4) is configured to vibrate ata resonance frequency (Fr) of the acoustic membranes (1, 2, 3, 4) for generating respective acoustic waves (W1,W2,W3,W4). Relative phases (ΔΦ12,ΔΦ34) are determined at which the acoustic membranes (1, 2, 4, 5) are actuated for generating a predetermined interference pattern (C) between the acoustic waves (W1,W2,W3,W4). A lamb wavelength (As) is determined of lamb waves (Ws) at the resonance frequency (Fr) travelling through intermediate sections (lOi, lOj) of the foil between adjacent acoustic membranes (1,2; 3,4). Distances (X12,X34) of the intermediate sections (10i, 10j) between the adjacent acoustic membranes (1,2; 3,4) in the layout are determined in accordance with the relative phases (ΔΦ12,ΔΦ34) and the lamb wavelength for having the lamb waves (Ws), generated by one acoustic membrane (1,3), arrive in phase with an adjacent acoustic membrane (2,4).

A display device, a method for producing a display device, and a gesture recognition method are disclosed. The display device includes a display module including a base and an array substrate, a resin layer, a first electrode layer, a pixel definition layer, a light-emitting unit layer, a second electrode layer disposed opposite to the first electrode layer, and an encapsulation layer. The light-emitting unit layer is between the first electrode layer and the second electrode layer and includes a plurality of light-emitting units respectively in a plurality of openings of the pixel definition layer, and an ultrasonic sensor including the second electrode layer, a piezoelectric material layer between the first electrode layer and the pixel definition layer, and a third electrode layer between the pixel definition layer and the resin layer. The piezoelectric material layer includes a plurality of piezoelectric material units separated by the plurality of light-emitting units.

A micromachined ultrasonic transducer (MUT). The MUT includes: a substrate; a membrane suspending from the substrate; a bottom electrode disposed on the membrane; a piezoelectric layer disposed on the bottom electrode and an asymmetric top electrode is disposed on the piezoelectric layer. The areal density distribution of the asymmetric electrode along an axis has a plurality of local maxima, wherein locations of the plurality of local maxima coincide with locations where a plurality of anti-nodal points at a vibrational resonance frequency is located.

An ultrasonic sensor includes a substrate, a platen and an acoustic stack disposed between the substrate and the platen, including at least one piezoelectric layer. The ultrasonic transducer exhibits a signal-to-noise ratio of at least 4 over a frequency range of at least 9 to 16 MHz.

There are provided an acoustic wave transducing unit and a method for manufacturing the same, and an acoustic wave transducer. The acoustic wave transducing unit includes: a substrate; a first electrode on the substrate; a supporting portion on a side of the first electrode away from the substrate; a diaphragm layer on a side of the supporting portion away from the substrate; a release hole penetrating through at least the diaphragm layer; the supporting portion, the diaphragm layer and the first electrode define a vibration chamber, the vibration chamber is communicated with the release hole, the supporting portion is lattice-matched with the first electrode, the supporting portion is lattice-matched with the diaphragm layer; a material of the supporting portion can be decomposed into a metal simple substance and a gas under an action of laser; Photon Energy of the supporting portion is smaller than that of the diaphragm layer.

Embodiments of the present disclosure provide a method for manufacturing a fingerprint recognition method, a fingerprint recognition module, and a display device. The method for manufacturing the fingerprint recognition module includes: providing a backplane; forming a bonding terminal in a bonding area of the backplane; forming a sensing electrode in a fingerprint recognition area of the backplane; forming an insulation layer cladding the bonding terminal in the bonding area, and forming a piezoelectric material layer in the fingerprint recognition area, where an orthographic projection of the piezoelectric material layer on the backplane coincides with an orthographic projection of the sensing electrode on the backplane; performing polarization processing on the piezoelectric material layer; and peeling off the insulation layer.

A noise management system for a window includes an active noise control (ANC) module and a passive sound absorbing module. The ANC module is disposed in or adjacent a ventilation channel of the window and configured to substantially cancel low-frequency noise entering the ventilation channel. The passive sound absorbing module is disposed in or adjacent to the ventilation channel and configured to absorb both high-frequency noise entering the channel and harmonic sounds generated by the ANC module.

A sonar transmit array (11), comprising: a plurality of transmitters configured to generate an acoustic sonar signal, wherein at least one of the transmitters is a polyvinylidene difluoride, PVDF, piezoelectric device configured to generate at least part of the acoustic sonar signal. Some embodiments, include a receive array (12) and the associated receive array circuitry (14).

Acoustofluidic components in which at least one microfluidic element and at least one acoustic transducer element are arranged on a piezoelectric substrate and/or on a piezoelectric layer on a non-piezoelectric substrate and/or on a non-piezoelectric substrate on a piezoelectric layer. The at least one microfluidic element is arranged in at least one propagation direction of an acoustic wave excited by the acoustic transducer element and the at least one microfluidic element prepared at least partially by lamination and photolithographic structuring comprises a base, walls and a top. At least the top is prepared by lamination and photolithographic structuring, and the microfluidic element has top thicknesses of 0.01 to 10 times the wavelength of the acoustic wave excited by the acoustic transducer element.