A piezoelectric micromachined ultrasonic transducer (PMUT) device includes a layer of piezoelectric material that is activated and sensed by an electrode and a conductive plane layer. The conductive plane layer may be electrically connected to processing circuitry by a via that extends through the piezoelectric layer. One or more isolation trenches extend through the conductive plane layer to isolate the conductive plane layer from other conductive plane layers of adjacent PMUT devices of a PMUT array.

A sensor system for attachment to a casing includes at least one sensor element, where the sensor element is configured for detecting an environment property of an environment which, with the sensor system attached to the casing, is situated on the opposite side of the casing with respect to the sensor system. The sensor system also includes an encapsulation layer, where the sensor element is embedded in the encapsulation layer, and where the encapsulation layer has a contact surface for attaching the sensor system to the casing.

According to one embodiment, a drive circuit includes a first circuit part. The first circuit part includes a first detecting part, a second detecting part, a first circuit, and a second circuit. The first detecting part is configured to detect a first piezoelectric element current flowing in a first piezoelectric element, and output a first detection signal corresponding to the first piezoelectric element current. The second detecting part is configured to detect a first capacitance element current flowing in a first capacitance element, and output a second detection signal corresponding to the first capacitance element current. The first circuit includes a first input terminal and a second input terminal. The first circuit is configured to apply a first drive signal to the first piezoelectric element and the first capacitance element. The second circuit is configured to supply a first differential signal to the second input terminal.

An electro-acoustical transducer such as a Piezoelectric Micromachined Ultrasonic Transducers is coupled with an adjustable load circuit having a set of adjustable load parameters including resistance and inductance parameters. Starting from at least one resonance frequency or at least one ring-down parameter of the electro-acoustical transducer a set of model parameters is calculated for a Butterworth-Van Dyke (BVD) model of the electro-acoustical transducer. The BVD model includes an equivalent circuit network having a constant capacitance coupled to a RLC branch and the adjustable load circuit is coupled with the electro-acoustical transducer at an input port of the equivalent circuit network of the model of the electro-acoustical transducer. The adjustable load parameters are adjusted as a function of the set of model parameters calculated for the BVD model of the electro-acoustic transducer to increase the bandwidth or the sensitivity of the electro-acoustic transducer.

Disclosed is a multi-silicon on insulator (SOI) micromachined ultrasonic transducer (MUT) device. The device comprises a multi-SOI substrate and a MUT. The MUT is affixed to a surface of the multi-SOI substrate. The multi-SOI substrate has a first SOI layer and at least a second SOI layer disposed above the first SOI layer. The first SOI layer and the second SOI layer each comprise an insulating layer and a semiconducting layer. The first SOI layer further defines a cavity located under a membrane of a MUT and one or more trenches at least partially around a perimeter of the cavity.

An ultrasonic transducer includes first and second acoustic transducers and a housing with a bottomed tubular shape. The second acoustic transducer includes an annular section supporting a second membrane section and contacting an entire periphery of the second membrane section, and an acoustic matching plate facing the second membrane section and spaced apart from the second membrane section. The acoustic matching plate is connected to a surrounding wall portion defining a sealed space with the housing. An ultrasonic transmission path sandwiched between the first membrane section and the second membrane section is provided in the sealed space. A maximum inner width of the ultrasonic transmission path is smaller than a maximum inner width of the surrounding wall portion.

An actuator includes a piezoelectric element, a vibration plate, and a support. The vibration plate has the piezoelectric element joined thereto and vibrates in accordance with displacement of the piezoelectric element. The support supports the vibration plate. A holder is disposed on the vibration plate. The holder is configured to join the vibration plate to an object of vibration. The vibration plate and the support are integrally molded.

A method of manufacturing a semiconductor device includes: forming a first substrate includes a membrane stack over a first dielectric layer, the membrane stack having a first electrode, a second electrode over the first electrode and a piezoelectric layer between the first electrode and the second electrode, a third electrode over the first dielectric layer, and a second dielectric layer over the membrane stack and the third electrode; forming a second substrate, including: a redistribution layer (RDL) over a third substrate, the RDL having a fourth electrode; and a first cavity on a surface of the RDL adjacent to the fourth electrode; forming a second cavity in one of the first substrate and the second substrate; and bonding the first substrate to the second substrate.

A diaphragm for a piezoelectric micromachined ultrasonic transducer (PMUT) is presented having resonance frequency and bandwidth characteristics which are decoupled from one another into independent variables. Portions of at least the piezoelectric material layer and backside electrode layer are removed in a selected pattern to form structures, such as ribs, in the diaphragm which retains stiffness while reducing overall mass. The patterned structure can be formed by additive, or subtractive, fabrication processes.

A sound transducer, in particular, for an ultrasonic sensor, includes a functional group, the functional group including a diaphragm cup and at least one electroacoustic transducer element. The sound transducer also includes a housing. The diaphragm cup includes a vibratory diaphragm and a circumferential wall, and at least one electroacoustic transducer element, the transducer element being configured to stimulate the diaphragm to vibrate and/or to convert vibrations of the diaphragm into electrical signals. The diaphragm cup is formed from a plastic material, the at least one transducer element being integrated into the vibratory diaphragm, in particular without an additional adhesive layer, the transducer element including a piezoceramic element.