A microelectromechanical system includes a lower membrane including a plurality of troughs and crests arranged alternately, an upper membrane including a plurality of troughs and crests arranged alternately, and a spacer layer disposed between the lower membrane and the upper membrane. The spacer layer includes counter electrode walls and support walls made of nitride, the counter electrode walls being provided with conductive elements. Chambers are formed between the troughs of the lower membrane and the crest of the upper membrane and the counter electrode walls are suspended in the chambers respectively. The support walls are sandwiched between the crests of the lower membrane and the troughs of the upper membrane with a space formed between adjacent support walls. The spaces between adjacent support walls may be empty or filled with oxide. Unwanted capacitance between the upper and lower membranes is reduced significantly.

A condenser microphone comprises a substrate, a vibratile diaphragm and a back plate. The substrate has an opening. The diaphragm is disposed corresponding to the substrate and covers the opening, and has a plurality of protrusions. The back plate is coupled to the diaphragm and has a plurality of through holes, at least some of which are corresponding to the protrusions respectively. An interval is formed between the diaphragm and the back plate, and when the diaphragm vibrates, the protrusions move into or further near the through holes.

A condenser microphone comprises a substrate, a vibratile diaphragm and a back plate. The substrate has an opening. The diaphragm is disposed corresponding to the substrate and covers the opening, and has a plurality of protrusions. The back plate is coupled to the diaphragm and has a plurality of through holes, at least some of which are corresponding to the protrusions respectively. An interval is formed between the diaphragm and the back plate, and when the diaphragm vibrates, the protrusions move into or further near the through holes.

A speaker is disclosed, which comprises a vibration system and a magnetic circuit system cooperating with the vibration system. The vibration system includes a speaker diaphragm, the speaker diaphragm comprises two surface layers compounded together and at least one intermediate layer positioned between the two surface layers, at least one of the surface layers is a thermoplastic polyester elastomer film layer, the at least one intermediate layer is an adhesive layer, the speaker diaphragm has Young's modulus of 5-700 MPa and an amplitude of 0.25 mm-1 mm, and the speaker has F.sub.0 of 150-1500 Hz. The speaker has a good sounding effect.

An acoustic diaphragm made at least in part from an expanded material. The expanded material includes one or more of cellulose, synthetic fibers and glass fibers. The expanded material has more than about 55% by volume voids.

Provided is a PCB speaker and a method for micromachining the speaker diaphragm on PCB substrate, the method for micromachining the speaker diaphragm on PCB substrate comprises: providing metal paths and at least one through hole on the PCB substrate; providing a patterned sacrificial layer on the PCB substrate, the sacrificial layer covering all the through holes on the PCB substrate; providing a diaphragm layer on the sacrificial layer through depositing, mounting or laminating, the diaphragm layer covering the sacrificial layer and electrically connected with the metal paths on the PCB substrate, thereby forming a diaphragm layer; and releasing the sacrificial layer and the diaphragm layer remains. With the micromachining method for the above PCB substrate and the diaphragm, the production cost of the speaker can be lowered, and the reliability of the product can be improved at the same time.

A diaphragm structure including a suspension side edge and a central part is provided. The suspension side edge is connected to a periphery of the central part and surrounds the central part. The central part includes a main body part and a structural strengthening part, and the structural strengthening part is formed at a top end of the main body part.

The present disclosure relates to a balanced armature receiver diaphragm including a paddle (202) flexibly coupled to a frame (204) and spaced apart therefrom by a gap (206). The paddle comprises a material having a specific modulus kg/m.sup.3) in at least one direction and density selected to increase stiffness and reduce mass. In one implementation, at least the paddle includes a carbon fiber material. The resulting paddle has improved acoustic performance including improved frequency response and less resonance in the audio band, among other benefits.

The present disclosure relates to a balanced armature receiver diaphragm including a paddle (202) flexibly coupled to a frame (204) and spaced apart therefrom by a gap (206). The paddle comprises a material having a specific modulus kg/m.sup.3) in at least one direction and density selected to increase stiffness and reduce mass. In one implementation, at least the paddle includes a carbon fiber material. The resulting paddle has improved acoustic performance including improved frequency response and less resonance in the audio band, among other benefits.

A sensor includes a substrate; and a corrugated diaphragm offset from the substrate. The corrugated diaphragm is configured to deflect responsive to a sound wave impinging on the corrugated diaphragm. A cavity is defined between the corrugated diaphragm and the substrate, the corrugated diaphragm forming a top surface of the cavity and the substrate forming a bottom surface of the cavity. A pressure in the cavity is lower than a pressure outside of the cavity.