Chirp Microsystems Inc.

University of California

Invensense, Inc.

Andre Guedes

David Horsley

Stefon Shelton

Richard J Przybyla

Meng-Hsiung Kiang

Bernhard Boser

Benedict Costello

Fabian T Goericke

Gerardo Jaramillo

A piezoelectric micromachined ultrasonic transducer (PMUT) device includes a substrate having an opening therethrough and a membrane attached to the substrate over the opening. An actuating structure layer on a surface of the membrane includes a piezoelectric layer sandwiched between the membrane and an upper electrode layer. The actuating structure layer is patterned to selectively remove portions of the actuating structure from portions of the membrane to form a central portion proximate a center of the open cavity and three or more rib portions projecting radially outward from the central portion.

Piezoelectric micromachined ultrasonic transducer with a patterned membrane structure

A transducer includes first and second piezoelectric layers made of corresponding different first and second piezoelectric materials and three or more electrodes, implemented in two or more conductive electrode layers. The first piezoelectric layer is sandwiched between a first pair of electrodes and the second piezoelectric layer is sandwiched between a second pair of electrodes. The first and second pairs of electrodes contain no more than one electrode that is common to both pairs.

Micromachined ultrasound transducer using multiple piezoelectric materials

A package design for a micromachined ultrasound transducer (MUT) utilizing curved geometry to control the presence and frequency of acoustic resonant modes is described. The approach consists of reducing in number and curving the reflecting surfaces present in the package cavity to adjust the acoustic resonant frequencies to locations outside the band of interest. The design includes a cavity characterized by a curved geometry and a MUT mounted to a side of a substrate facing the cavity with a sound emitting portion of the MUT facing an opening in the substrate. The substrate is disposed over an opening of the cavity with the substrate oriented such that the MUT located within the cavity.

Miniature ultrasonic transducer package

A piezoelectric micromachined ultrasound transducer (PMUT) is disclosed. The device consists of a flexible membrane that is connected to a rigid substrate via flexures. The flexures are defined by slots etched through the perimeter of the membrane. These features release the stress present on the structural layers of the membrane, making it less sensitive to residual stress. The flexures are designed to act as torsion springs so that the membrane's vibration mode shape is highly curved in the piezoelectric actuation area, thereby increasing the electromechanical coupling.

Piezoelectric micromachined ultrasonic transducers having stress relief features

A piezoelectric micromachined ultrasonic transducer (pMUT) device may include a piezoelectric membrane transducer designed to have lower sensitivity to residual stress and reduced sensitivity to geometric variations arising from the backside etching process used to release the membrane. These designs allow some of its key feature to be adjusted to achieve desired characteristics, such as pressure sensitivity, natural frequency, stress sensitivity, and bandwidth.

Piezoelectric micromachined ultrasonic transducers with low stress sensitivity and methods of fabrication

An apparatus comprises an ultrasonic transducer having a first and second electrode and switches which configured to selectively connect the first and second electrodes to a transmit voltage source or to a receive amplifier. The switches are configured to selectively connect a first input of the amplifier to the first electrode of the transducer and to selectively connect a second input of the amplifier to the second electrode of the transducer. The switches are also configured to selectively connect the voltage source to the first and second electrodes of the transducer. The transducer may include a piezoelectric layer attached to and sandwiched between the first electrode and the second electrode, and a flexible membrane attached to the first electrode. The piezoelectric layer may be patterned to form an annular ring at the outer diameter of the flexible membrane.

Piezoelectric micromachined ultrasonic transducers having differential transmit and receive circuitry

A system and method use an array of ultrasonic transducers to emit and receive sound in a phased array fashion by using acoustic waveguides to achieve a desired acoustic radiation and reception pattern. A chip package attached to an acoustic transducer array includes acoustic waveguides coupled to acoustic ports. Each waveguide is coupled between a corresponding acoustic transducer and a corresponding acoustic port. A spacing of a pair of acoustic ports is different than a spacing of a corresponding pair of acoustic transducers.

Package waveguide for acoustic sensor with electronic delay compensation

A piezoelectric micromachined ultrasound transducer (PMUT) is disclosed. The PMUT consists of a flexural membrane that is piezoelectrically actuated. These membranes are formed on a first substrate that is bonded to a second substrate. The two substrates are separated by an air gap to allow the PMUT to vibrate. Several methods for joining the two substrates are described.

Piezoelectric micromachined ultrasonic transducers using two bonded substrates

A miniature rangefinder includes a housing, a micromachined ultrasonic transducer, and signal processing circuitry. The housing includes a substrate and a lid. The housing has one or more apertures and the micromachined ultrasonic transducer is mounted over an aperture. The micromachined ultrasonic transducer may function as both a transmitter and a receiver. An integrated circuit is configured to drive the transducer to transmit an acoustic signal, detect a return signal, and determine a time of flight between emitting the acoustic signal and detecting the return signal.

Miniature micromachined ultrasonic rangefinder

A piezoelectric micromachined ultrasonic transducer (PMUT) device includes a substrate having an opening therethrough and a membrane attached to the substrate over the opening. A portion of the membrane that overlies the opening is divided into a plurality of cantilevers that are mechanically coupled so that the cantilevers resonate at a common frequency.

Micromachined ultrasonic transducers with a slotted membrane structure

An apparatus for determining location of a moveable object in relation to an input device includes an array of one or more piezoelectric micromachined ultrasonic transducer (pMUT) elements and a processor. The array is formed from a common substrate. The one or more pMUT elements include one or more transmitters and one or more receivers. The processor configured to determine a location of a moveable object in relation to an input device using sound waves that are emitted from the one or more transmitters, reflected from the moveable object, and received by the one or more receivers.

In-air ultrasonic rangefinding and angle estimation

A magnetic-field sensor that provides an output signal in response to an external magnetic field is described. This magnetic-field sensor includes a pair of cantilevers separated by a horizontal gap, which is displaced vertically over an open cavity by applying a time-varying voltage having a fundamental frequency across piezoelectric layers in the pair of cantilevers. The pair of cantilevers also includes magnetic-flux concentrators that convey the external magnetic field to the horizontal gap between the pair of cantilevers. A stationary magnetoresistive sensor in the horizontal gap transforms the external magnetic field into an output signal. Because the pair of cantilevers is displaced vertically at the fundamental frequency, the output signal includes a modulation signal corresponding to the external magnetic field centered around twice the fundamental frequency. This modulation of the external magnetic field allows 1/f noise to be suppressed, thereby improving the sensitivity of the magnetic-field sensor.

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Lisbon, Portugal

Andre Guedes