A dual-diaphragm differential capacitive microphone includes: a back plate, a first diaphragm, and a second diaphragm. The first diaphragm is insulatively supported on a first surface of the back plate, where the back plate and the first diaphragm form a first variable capacitor. The second diaphragm is insulatively supported on a second surface of the back plate, where the back plate and the second diaphragm form a second variable capacitor. The back plate is provided with at least one connecting hole. The second diaphragm is provided with a recess portion recessed towards the back plate, where the recess portion passes through the connecting hole and is connected to the first diaphragm. The dual-diaphragm differential capacitive microphone achieves a higher signal-to-noise ratio.

The disclosure describes devices and methods of providing a DC bias voltage in a microphone assembly. Particularly, one implementation of such a device may be implemented on an integrated circuit that includes a direct current (DC) bias circuit. The DC bias circuit may be coupled to a transducer and configured to supply a DC bias signal to the transducer. The DC bias circuit includes a multi-stage charge pump and a low pass filter (LUFF) circuit. The multi-stage charge pump includes transistors that are fabricated with deep trench isolation (DTI).

A robust MEMS transducer includes a kinetic energy diverter disposed within its frontside cavity. The kinetic energy diverter blunts or diverts kinetic energy in a mass of air moving through the frontside cavity, before that kinetic energy reaches a diaphragm of the MEMS transducer. The kinetic energy diverter renders the MEMS transducer more robust and resistant to damage from such a moving mass of air.

The present invention provides a process of fabricating a capacitive microphone such as a MEMS microphone. In the process, one electrically conductive layer is deposited on a removable layer, and then divided or cut into two divided layers, both of which remain in contact with the removable layer as they were. One of the two divided layers will become or include a movable or deflectable membrane/diaphragm that moves in a lateral manner relative to another layer, instead of moving toward/from another layer. A motional sensor is optionally fabricated within the microphone to estimate the noise introduced from acceleration or vibration of the microphone for the purpose of compensating the microphone output through a signal subtraction operation.

The present application relates to graphene-based transducing devices, including micromechanical ultrasonic transducers and electret transducers. A micromachined ultrasonic transducer comprising: a backing layer, a spacer layer, and a diaphragm comprising a material selected from the group consisting of graphene, h-BN, MoS2, and combinations thereof, wherein the backing layer comprises a first etched semiconductor, glass, or polymer, wherein the spacer layer comprises a second etched semiconductor, glass, or polymer.

One of the main objects of the present invention is to provide a MEMS speaker with improved high frequency acoustic performance. To achieve the above-mentioned object, the present invention provides a MEMS speaker including a base with a first cavity and two openings opposite to each other; a substrate covering one of the openings; a diaphragm fixed to the base and covers the other opening; and a MEMS driver. The MEMS driver includes a first support part forming a distance from the diaphragm, a second support part extending from an edge of the first support part toward the diaphragm for supporting the diaphragm, and a piezoelectric member attached to the first support part.

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.

Provided is a composition for an acoustic wave probe including a polysiloxane mixture containing at least polysiloxane having a vinyl group and a phenyl group, polysiloxane having two or more Si—H groups in a molecular chain, and zinc oxide, a silicone resin for an acoustic wave probe, the acoustic wave probe, an acoustic wave measurement apparatus, an ultrasound diagnostic apparatus, an ultrasound probe, a photoacoustic wave measurement apparatus, and an ultrasound endoscope.

Provided is a composition for an acoustic wave probe including a polysiloxane mixture containing at least polysiloxane having a vinyl group and a phenyl group, polysiloxane having two or more Si—H groups in a molecular chain, and zinc oxide, a silicone resin for an acoustic wave probe, the acoustic wave probe, an acoustic wave measurement apparatus, an ultrasound diagnostic apparatus, an ultrasound probe, a photoacoustic wave measurement apparatus, and an ultrasound endoscope.

A capacitive transducer or microphone includes a first substrate of one or more layers and which includes a first surface, a first cavity in the first surface, and a mesa diaphragm that spans the first cavity. The capacitive transducer or microphone includes a second substrate fixed to the first substrate. The second substrate has one or more layers which includes a second cavity having a nonplanar (e.g., contoured or structured or stepped) bottom surface that faces the mesa diaphragm. A shape or relief of the bottom surface of the cavity may advantageously be, to at least some degree, complementary to a deformed shape of the diaphragm. The second substrate may include one or more acoustic holes, non-uniformly distributed thereacross. One or more vents may vent the second cavity.