A diaphragm of a MEMS microphone is configured to generate a displacement thereof in response to an applied acoustic pressure, and the diaphragm includes a plurality of vent holes having a bent shape to increase the length of the vent holes.

A modular fan unit of a diagonal and/or axial fan having a housing that includes an inlet opening and an outflow opening. The housing accommodates a fan, that conveys the air at least in the axial direction and is divided perpendicularly to an axis (X-X) of the fan into at least two housing halves that are joined together. The housing forms a chamber in which the blades of the fan rotate around an axis and has a circumferential edge area in the vicinity of which the housing has a thickness B extending in the axis direction of the fan. A motor holding part has a dimension R as the maximum extension in the edge area and the chamber has an extension in the axis direction of the fan at a height of a dimension L, whereas the extension of the air inlet part has a dimension T in the area of the chamber. A ratio of the dimension B to the dimension R with respect to the ratio of the dimension L to the dimension T is within the range from 0.9 to 1.2. The noise emission of the fan during operation is minimized and the outer diameter of the modular fan unit is kept to a minimum.

Microphone systems including a MEMS microphone and an electronic controller. The MEMS microphone includes a movable membrane and a backplate. The movable membrane includes a capacitive electrode and a piezoelectric electrode. The capacitive electrode is configured such that acoustic pressures acting on the movable membrane cause movement of the capacitive electrode. The piezoelectric electrode alters a mechanical property of the MEMS microphone based on a control signal. The backplate is positioned on a first side of the movable membrane. The electronic controller is electrically coupled to the piezoelectric electrode and is configured to generate the control signal.

Microphone systems including a MEMS microphone and an electronic controller. The MEMS microphone includes a movable membrane and a backplate. The movable membrane includes a capacitive electrode and a piezoelectric electrode. The capacitive electrode is configured such that acoustic pressures acting on the movable membrane cause movement of the capacitive electrode. The piezoelectric electrode alters a mechanical property of the MEMS microphone based on a control signal. The backplate is positioned on a first side of the movable membrane. The electronic controller is electrically coupled to the piezoelectric electrode and is configured to generate the control signal.

There is disclosed a microphone and a microphone capsule including the microphone. The microphone includes a diaphragm having a perimeter shaped as a polygon with an odd number of sides.

There is disclosed a microphone and a microphone capsule including the microphone. The microphone includes a diaphragm having a perimeter shaped as a polygon with an odd number of sides.

A loudspeaker having a cylindrical sound-producing membrane includes an acoustic lens which radially surrounds the membrane. The membrane is composed of wire mesh formed into a cylinder. The cylindrical membrane is positioned on the magnet structure by an inner supporting cylindrical core column. Sound from the membrane is fractionally redirected by the lens which is centered along the axis of the membrane. The lens includes a plurality of radially disposed petals that reflect a portion of the sound. The base of the lens supports and mounts the loudspeaker magnet and driver assembly.

A low-profile ultrasonic wave generation device is provided that includes a drive unit having a piezoelectric member and an electrode formed on a surface of the piezoelectric member. The drive unit as a whole vibrates flexurally. The connection member is connected to a portion of the drive unit that includes a point of maximum displacement of the drive unit when the drive unit is subjected to flexural vibration. The vibrating unit is connected to the connection member. The vibrating unit vibrates due to the flexural vibration of the drive unit being transmitted by the connection member and thereby generates ultrasonic waves.

In a diaphragm 1, at a front surface side surface layer of a base material 10 made of pulps 20 which are mainly composed of cellulose, a mixed layer 11 in which the pulps 20, mica 22, and cellulose nanofibers 21 are mixed is formed.

A vibration component includes a dome, a diaphragm, and a voice coil. The dome includes a porous heat dissipation layer, the diaphragm partially covers a portion of a surface of the dome, and the voice coil is connected with a side of the dome facing away from the diaphragm.