An acoustic sensor (e.g., for use in a piezoelectric MEMS microphone) includes a substrate and a cantilever beam attached to the substrate. The cantilever beam has a proximal portion attached to the substrate and extends to a distal tip at a free end thereof. The cantilevered beam has a multilayer structure with a plurality of piezoelectric layers and a plurality of metal electrode layers, at least a portion of one of the piezoelectric layers interposed between two metal electrode layers. One or more direct current voltage sources are electrically connected to one or more of the plurality of metal electrode layers and configured to apply a direct current bias voltage between at least two of the plurality of metal electrode layers to deflect the cantilever beam to at least partially counteract a deflection of the cantilever beam due to a residual stress in the cantilever beam.

A vibration sensing assembly, including a base, a side shell, a sensor, an upper cover, and a diaphragm assembly, is provided. The base includes first and second bottom plates. A first cavity is formed between the first and second bottom plates. The second bottom plate includes first and second through holes. The side shell is disposed on the second bottom plate and includes a cylinder and an inner partition. The inner partition divides the cylinder into a second cavity and an airflow channel. The airflow channel is communicated with the first cavity through the first through hole. The sensor is disposed in the second cavity and covers the second through hole. The side shell is located between the base and the upper cover. The base, the side shell, and the upper cover jointly form an outer shell. The diaphragm assembly is disposed between the side shell and the upper cover.

A microelectromechanical systems device includes a vibrator and a reinforcing film. The vibrator includes a piezoelectric element configured to convert pressure to an electrical signal. The reinforcing film is configured to reinforce strength of the vibrator. The vibrator further has a groove at which a portion of the reinforcing film is disposed.

A micro-electro mechanical device includes a casing, a vibration sensor, a vibration membrane assembly, and a micro-electro mechanical microphone. The casing has a sound-receiving hole, and the vibration sensor is disposed in the casing. The vibration membrane assembly is disposed in the casing and corresponds to the vibration sensor. The micro-electro mechanical microphone is disposed in the casing and corresponds to the sound-receiving hole, and a back cavity of the micro-electro mechanical microphone is formed in the casing. The back cavity at least partially overlaps with areas corresponding to a vertical projection of the vibration membrane assembly.

A method of making an acoustic sensor (e.g., a piezoelectric sensor for a piezoelectric microelectromechanical systems microphone) includes forming or depositing one or more piezoelectric layers to define a beam extending between a proximal portion and a distal tip (e.g., unsupported free end), the beam having a width in plan view that is greater at a location distal of the proximal portion than at the proximal portion. The method also comprises attaching the beam to a substrate in cantilever form so that the proximal portion of the beam is anchored to the substrate and the distal tip is a free unsupported end of the beam. One or more electrodes are disposed on or in the proximal portion of the beam.

A MEMS microphone includes a substrate having an opening, a first diaphragm, a first backplate, a second diaphragm, and a backplate. The first diaphragm faces the opening in the substrate. The first backplate includes multiple accommodating-openings and it is spaced apart from the first diaphragm. The second diaphragm joints the first diaphragm together at multiple locations by pillars passing through the accommodating-openings in the first backplate. The first backplate is located between the first diaphragm and the second diaphragm. The second backplate includes at least one vent hole and it is spaced apart from the second diaphragm. The second diaphragm is located between the first backplate and the second backplate.

A flexible vibration module is disclosed. The flexible vibration module includes a piezoelectric composite layer, including: a plurality of piezoelectric portions each having a piezoelectric characteristic, where at least two of the plurality of piezoelectric portions have different sizes; and a flexible portion between the plurality of piezoelectric portions.

An optical microphone with a dual light source is provided. The optical microphone includes: a housing including an inner cavity and a sound inlet communicating the inner cavity with the outside; a MEMS module disposed in the inner cavity and including a flexible membrane and two gratings; two photoelectric modules, one being disposed in a front cavity and the other in a rear cavity, and each of the photoelectric modules including a light source and a light detector; and an ASIC module disposed in the rear cavity and electrically connected to the photoelectric modules. The optical microphone provides differential measurement, such that the output signal change on one of the two sides of the flexible membrane is positive and the output signal change on another side of the flexible membrane is negative. Therefore, a differential measurement structure is formed to improve the performance of the microphone.

A micromechanical component for a sensor device or microphone device. The micromechanical component includes a diaphragm with a diaphragm inner side to which an electrode structure is directly or indirectly connected; and a cavity that is formed at least in a volume that is exposed by at least one removed area of at least one sacrificial layer. At least one residual area made of at least one electrically insulating sacrificial layer material of the at least one sacrificial layer is also present at the micromechanical component, and including at least one insulation area made of at least one electrically insulating material that is not the same as the electrically insulating sacrificial layer material. The electrode structure is electrically insulated from the diaphragm, and/or the at least one residual area of the at least one sacrificial layer is delimited from the cavity, using the at least one insulation area.

Provided is a cover member for an electronic device, the cover member having a through hole extending between a first surface and a second surface. The cover member for an electronic device includes a plurality of long particles that are present in an inner wall facing the through hole and whose longitudinal direction is along a through axis of the through hole in a cross section including the through axis.