A microelectromechanical systems (MEMS) die includes a first diaphragm and a second diaphragm, wherein the first diaphragm and the second diaphragm bound a sealed chamber. A stationary electrode is disposed within the sealed chamber between the first diaphragm and the second diaphragm. A tunnel passes through the first diaphragm and the second diaphragm without passing through the stationary electrode, wherein the tunnel is sealed off from the chamber. The MEMS die further includes a substrate having an opening formed therethrough, wherein the tunnel provides fluid communication from the opening, through the second diaphragm, and through the first diaphragm.

A micro-electro-mechanical system (MEMS) microphone is provided. The MEMS microphone includes a substrate, a diaphragm, a backplate and a first protrusion. The substrate has an opening portion. The diaphragm is disposed on one side of the substrate and extends across the opening portion of the substrate. The backplate includes a plurality of acoustic holes. The backplate is disposed on one side of the diaphragm. An air gap is formed between the backplate and the diaphragm. The first protrusion extends from the backplate towards the air gap.

A piezoelectric microelectromechanical systems microphone can be mounted on a printed circuit board. The microphone can include a substrate with an opening between a bottom end of the substrate and a top end of the substrate. The microphone can include a single piezoelectric film layer disposed over the top end of the substrate and defining a diaphragm structure, the single piezoelectric film layer having substantially zero residual stress and formed from a piezoelectric wafer. The microphone can include one or more electrodes disposed over the diaphragm structure. The diaphragm structure is configured to deflect when subjected to sound pressure via the opening in the substrate.

In at least one embodiment, a microphone assembly including a substrate, a printed circuit board (PCB), a micro-electro-mechanical systems (MEMS) transducer, a first lid, and a second lid is provided. The substrate defines a first port that extends completely therethrough. The PCB defines a sound opening that extends completely therethrough. The MEMS transducer is positioned on a first side of the substrate. The first lid defines a second port and covers the MEMS transducer and the first port. The first lid and the substrate define a front volume of air that surrounds the MEMS transducer. The second lid is positioned on the second side of the PCB. A cavity of the second lid, the sound opening of the PCB, the sound opening of the PCB, and the first port of the substrate define a back volume of air that is greater than the front volume of air.

A piezoelectric microelectromechanical systems device can include a cavity bounded by walls and an asymmetrical bimorph structure at least partially spanning the cavity that includes at least a piezoelectric layer and two electrode layers. The electrode layers can have relative thicknesses configured to compensate for expected temperature stress in the bimorph structure. Thus, metals having different thicknesses can be positioned and configured to compensate deflection due to thermal stress of any or all of the piezoelectric layer, the first metal layer, and second metal layer and a substrate. A method for making the piezoelectric microelectromechanical systems device is also provided.

The present disclosure relates to a transducer assembly including a transducer having a movable member, and a servo-loop controller configured to compensate for effects of a disturbance on the transducer assembly by adjusting a bias voltage applied to the transducer. A servo-loop controller having a smaller bandwidth for out-of-band disturbances than for in-band disturbances and configured to control the bias voltage based on a feedback signal generated by a sensor that detects an effect of the disturbance on the transducer assembly. The transducer assembly can be implemented as a microphone or a speaker among other sensors and actuators.

An alternate venting path can be employed in a sensor device for pressure equalization. A sensor component of the device can comprise a diaphragm component and/or backplate component disposed over an acoustic port of the device. The diaphragm component can be formed with no holes to prevent liquid or particles from entering a back cavity of the device, or gap between the diaphragm component and backplate component. A venting port can be formed in the device to create an alternate venting path to the back cavity for pressure equalization for the diaphragm component. A venting component, comprising a filter, membrane, and/or hydrophobic coating, can be associated with the venting port to inhibit liquid and particles from entering the back cavity via the venting port, without degrading performance of the device. The venting component can be designed to achieve a desired low frequency corner of the sensor frequency response.

Non-limiting examples of the present disclosure relate to devices, systems and methods of manufacture for an exemplary waveguide usable for acoustic signal transmission for non-destructive evaluation (NDE) of a wooden specimen. An exemplary waveguide comprises a mating portion for interfacing with a transducer horn of an ultrasonic transducer. The mating portion comprises an impact surface and a contact well that is fabricated within the impact surface so that the contact well is not contacted during an impact that drives the waveguide into wood. The contact well is utilized to connect the waveguide to a transducer horn. The waveguide further comprises a body portion that comprises a radiating component optimized for non-destructive evaluation (NDE) of wood and transmission of ultrasonic signal data. Further non-limiting examples describe an interfacing component for securing one or more devices to the waveguide as well as an extraction component that is configured to minimize damage to the waveguide during extraction.

A micro electrical mechanical systems (MEMS) device includes a flexible membrane disposed over a substrate, and a first backplate disposed over the flexible membrane. The first backplate includes a first plurality of bumps facing the flexible membrane. The MEMS device further includes a plurality of features disposed at the flexible membrane, where each of the plurality of features being associated with a corresponding one of the first plurality of bumps.

A piezoelectric microelectromechanical systems diaphragm microphone can be mounted on a printed circuit board. The microphone can include a substrate with an opening between a bottom end of the substrate and a top end of the substrate. The microphone can have two or more piezoelectric film layers disposed over the top end of the substrate and defining a diaphragm structure. Each of the two or more piezoelectric film layers can have a predefined residual stress that substantially cancel each other out so that the diaphragm structure is substantially flat with substantially zero residual stress. The microphone can include one or more electrodes disposed over the diaphragm structure. The diaphragm structure is configured to deflect when the diaphragm is subjected to sound pressure via the opening in the substrate.