PIEZOELECTRIC SPEAKER, PIEZOELECTRIC AUDIO DEVICE EMPLOYING PIEZOELECTRIC SPEAKER, AND SENSOR WITH ALERT DEVICE ATTACHED

摘要

Disclosed is a piezoelectric speaker with a large sound pressure, a piezoelectric audio device, and a sensor with an alert device attached, employing same, with respect to a low frequency region and a high frequency region. A piezoelectric speaker (1) comprises a piezoelectric oscillator (2), further comprising a piezoelectric body (21) formed from a piezoelectric element, and a plate, further comprising a diameter greater than the diameter of the piezoelectric body (21), the plate being mounted upon a surface of the piezoelectric body (21) in a concentric state, and a film body (3), which is installed upon a periphery of the piezoelectric oscillator (2) and maintains the piezoelectric oscillator in an elastic state, wherein the film body (3) further comprises a rough and fine portion further comprising a physically rough portion that may be a peak portion (3M) and/or a valley portion (3V) upon an external circumference direction thereof, the film body (3) is further positioned to correspond to a fixed frequency of an in-phase mode wherein peaks, valleys, and nodes are formed in a concentric circle, and the piezoelectric oscillator (2) and the film body (3) form a sound emission body.