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.

Sensors used in mapping strata beneath a marine body are described, such as used in a flexible towed array. A first sensor is a motion sensor including a conductive liquid in a chamber between a rigid tube and a piezoelectric motion film circumferentially wrapped about the tube. A second sensor is a traditional acoustic sensor or a novel acoustic sensor using a piezoelectric sensor mounted with a thin film separation layer of flexible microspheres on a rigid substrate. Additional non-acoustic sensors are optionally mounted on the rigid substrate for generation of output used to reduce noise observed by the acoustic sensors. Combinations of acoustic, non-acoustic, and motion sensors co-located in rigid streamer housing sections are provided.

An ultrasound transducer array is incorporated in a light-weight, conformable, and wearable patch that may be used to deliver, monitor, and control localized transcranial focused ultrasound (tFUS). The patch may include full-duplex transmit-receive circuitry that may be used for continuous monitoring of transcranial focused ultrasound (tFUS) application. The circuitry may include a circulator. The ultrasound transducer array may be coupled to an aperture interface having irregularly sized or shaped channel conductors to provide a coarse aperture for the array. The coarse aperture may be designed using a method that provides a reduced channel count.

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 transducer device includes a patterned film stack disposed on first regions of a substrate, the patterned film stack including a metal electrode layer and a bottom cavity layer formed on the metal electrode layer. The ultrasonic transducer device further includes a planarized insulation layer disposed on second regions of the substrate layer, a cavity formed in a membrane support layer and a CMP stop layer, the CMP stop layer including a top layer of the patterned film stack and the membrane support layer formed over the patterned film stack and the planarized insulation layer. The ultrasonic transducer device also includes a membrane bonded to the membrane support layer. The CMP stop layer underlies portions of the membrane support layer but not the cavity.

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.

A catheter-based imaging apparatus comprises a catheter having a proximal end and a distal end. An optical emitter is configured to emit optical excitation signals from a distal portion of the catheter. One or more ultrasound transducers are configured for: (a) transmission of acoustic excitation signals from the distal portion of the catheter; and (b) detection of ultrasound response signals from an object of interest at or near to the distal portion of the catheter at frequencies which include a lower receive frequency at least as low as 10 MHz and a higher receive frequency at least as high as 35 MHz. The one or more ultrasound transducers are thereby configured to detect response signals comprising photoacoustic response signals from the object of interest at the lower receive frequency and high resolution imaging signals from the object of interest at the higher receive frequency.

A method of fabricating a film vibration device, including: photoetching a surface of a silicon wafer to form a circular-hole array; etching an aluminum layer on the silicon wafer; etching the silicon wafer to form a through-hole array to obtain a porous silicon wafer; attaching a polyethylene terephthalate (PET) sheet to a side of the porous silicon wafer; ablating the PET sheet to obtain a porous PET film; attaching a polyvinylidene fluoride (PVDF) film to a lower side of the porous silicon wafer; performing vacuumization above the porous silicon wafer, while heating the PVDF film below the porous silicon wafer to create dome micro-structures on the PVDF film; and laminating the porous PET film on each of two sides of the PVDF film to obtain the film vibration device. This application also provides a cleaning device having the film vibration device.

An interventional device includes an elongate shaft (101) with a longitudinal axis (A-A′), and an ultrasound detector (102). The ultrasound detector (102) comprises a PVDF homopolymer foil strip (103). The foil strip (103) is wrapped around the longitudinal axis (A-A′) of the elongate shaft (101) to provide a band having an axial length (L) along the longitudinal axis (A-A′). The axial length (L) is in the range 80-120 microns.

An ultrasonic transducer device comprises a piezoelectric micromachined ultrasonic transducer (PMUT), a transmitter with first and second differential outputs, and a controller. The PMUT includes a membrane layer. A bottom electrode layer, comprising a first bottom electrode and a second bottom electrode, is disposed above the membrane layer. The piezoelectric layer is disposed above the bottom electrode layer. The top electrode layer is disposed above the piezoelectric layer and comprises a segmented center electrode disposed above a center of the membrane layer and a segmented outer electrode spaced apart from the segmented center electrode. The controller, responsive to the PMUT being placed in a transmit mode, is configured to couple the first and second segments of the bottom electrode layer with ground, couple the first output of the transmitter with the segments of the segmented center electrode, and couple the second output with the segments of the segmented outer electrode.