An apparatus may include a one- or two-dimensional array of micromechanical ultrasonic transducer (PMUT) elements positioned below, beside, with, on, or above a backplane of a visual display. The backplane may be a thin-film transistor (TFT) backplane. The array of PMUT elements may be a piezoelectric micromechanical ultrasonic transducer (PMUT) array or a capacitive micromechanical ultrasonic transducer (CMUT) array. The PMUT array may be configurable to operate in modes corresponding to multiple frequency ranges. When operating in the low-frequency mode, the apparatus may be capable of gesture detection. A high-frequency mode may include a fingerprint sensor mode or a stylus detection mode.

A microelectromechanical membrane transducer includes: a supporting structure; a cavity formed in the supporting structure; a membrane coupled to the supporting structure so as to cover the cavity on one side; a cantilever damper, which is fixed to the supporting structure around the perimeter of the membrane and extends towards the inside of the membrane at a distance from the membrane; and a damper piezoelectric actuator set on the cantilever damper and configured so as to bend the cantilever damper towards the membrane in response to an electrical actuation signal.

Substrate is produced by using a MEMS technique to form multiple diaphragms in a substrate by forming piezoelectric material layer on one surface of the substrate and thereafter by forming openings in the substrate from the other surface of the substrate; substrate and substrate on which signal detection circuit is formed are aligned to each other using at least one of multiple diaphragms as alignment diaphragm; and substrate and substrate are bonded together.

Methods for improving the electromechanical coupling coefficient and bandwidth of micromachined ultrasonic transducers, or MUTs, are presented as well as methods of manufacture of the MUTs improved by the presented methods.

Microelectromechanical (MEMS) devices and associated methods are disclosed. Piezoelectric MEMS transducers (PMUTs) suitable for integration with complementary metal oxide semiconductor (CMOS) integrated circuit (IC), as well as PMUT arrays having high fill factor for fingerprint sensing, are described.

The disclosed method of diffusion bonding of a lead zirconate titanate piezoelectric crystal to a metal wear plate, for the fabrication of an ultrasonic transducer operable at high temperatures and able to withstand repeated thermal cycling, comprises depositing noble metal coatings on both bonding surfaces, bringing the surfaces into contact, and heating under pressure at a temperature ranging from 270 to 400° C.

A micromechanical device for transducing acoustic waves in a propagation medium, comprising: a body; a first electrode structure superimposed to the body and electrically insulated from the body, the first electrode structure and the body defining between them a first buried cavity; and a first piezoelectric element superimposed to the first electrode structure, wherein the body, the first electrode structure, and the buried cavity form a first capacitive ultrasonic transducer, and the first electrode structure and the first piezoelectric element form a first piezoelectric ultrasonic transducer.

Described are transducer assemblies and imaging devices comprising: a microelectromechanical systems (MEMS) die including a plurality of piezoelectric elements; a complementary metal-oxide-semiconductor (CMOS) die electrically coupled to the MEMS die by a first plurality of bumps and including at least one circuit for controlling the plurality of piezoelectric elements; and a package secured to the CMOS die by an adhesive layer and electrically connected to the CMOS die.

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.

According to various embodiments, a PMUT device may include a wafer, an active layer including a piezoelectric stack, an intermediate layer having a cavity therein where the intermediate layer is disposed between the wafer and the active layer such that the cavity is adjoining the piezoelectric stack. A via may be formed through the active layer and the intermediate layer to the wafer. A metallic layer may be disposed over the active layer and over surfaces of the via. The intermediate layer may include an interposing material surrounding the cavity, and may further include a sacrificial material surrounding the via. The sacrificial material may be different from the interposing material. The metallic layer may include a first member at least substantially overlapping the piezoelectric stack, a second member extending from the first member to the cavity, and a third member extending into the active layer to contact an electrode therein.