Various embodiments of the present disclosure are directed to a normally-open piezoelectric microelectromechanical systems (MEMS) device. A cantilever has a first end overlying and bonded to a substrate and further has a second end, opposite the first end, overlying an actuator cavity. A piezoelectric actuator is on the cantilever. A valve vane is bonded to the second end of the cantilever and further overlies a valve cavity laterally adjacent to the actuator cavity. The cantilever curves downward from the first end to the second end, such that the valve vane is inclined and the valve cavity is open. Actuation of the piezoelectric actuator curves the cantilever upward to close the valve cavity.

Various embodiments of the present disclosure are directed to a normally-open piezoelectric microelectromechanical systems (MEMS) device. A cantilever has a first end overlying and bonded to a substrate and further has a second end, opposite the first end, overlying an actuator cavity. A piezoelectric actuator is on the cantilever. A valve vane is bonded to the second end of the cantilever and further overlies a valve cavity laterally adjacent to the actuator cavity. The cantilever curves downward from the first end to the second end, such that the valve vane is inclined and the valve cavity is open. Actuation of the piezoelectric actuator curves the cantilever upward to close the valve cavity.

A loudspeaker includes a support frame, a first diaphragm assembly, a second diaphragm assembly, a first vibration assembly, and a second vibration assembly; the first vibration assembly includes a first piezoelectric cantilever, the first piezoelectric cantilever includes a first fixed end connected to the support frame and a first free end suspended inside the support frame and connected to the first diaphragm assembly; the second vibration assembly includes a second piezoelectric cantilever, the second piezoelectric cantilever includes a second fixed end connected to the support frame and a second free end suspended inside the support frame and connected to the second diaphragm assembly; the first piezoelectric cantilever and the second piezoelectric cantilever are disposed opposite each other in a first direction, and the length of the first piezoelectric cantilever is different from the length of the second piezoelectric cantilever in the second direction perpendicular to the first direction.

A piezoelectric element includes a support member, a vibrator, a through electrode and a seed layer. The vibrator is disposed on an insulation film of the support member, and includes a piezoelectric film and an electrode coating film electrically connected to the piezoelectric film. The vibrator has a support region and a vibration region. The through electrode is electrically connected to the electrode coating film at the support region, and is disposed in a stacking direction of the support member and the vibrator. Between the piezoelectric film and the insulation film, the seed layer is disposed at a portion of the electrode coating film facing another portion of the electrode coating film connected to the through electrode in the stacking direction. The seed layer is made of material having a lattice constant closer to the piezoelectric film or material easier to cause the piezoelectric film to be self-aligned.