PURPOSE: To reduce a hysteresis due to temperature hysteresis substantially linearly at the temperature dependency of a resonance frequency and to improve the humidity resistance of a piezoelectric thin vibrator by forming an SiO 2 or TiO 2 film by high frequency sputtering, coating and drying organic metal compound solution containing mainly Pb, Zr, Ti on the obtained vibration plate, and then heat-treating it at a specific temperature in the atmosphere.
CONSTITUTION: The material of a vibration plate 1 is of Fe-42Ni alloy or stainless steel, and its thickness is preferably 20∼50μm. In order to prevent the plate 1 from oxidizing, an oxide of SiO 2 and TiO 2 is disposed on the surface. The thickness of the SiO 2 or TiO 2 film is preferably 0.1∼3μm. A thin piezoelectric film on the surface of the plate 1 can be obtained by dipping the plate 1 having the SiO 2 or TiO 2 film on the surface in organic metal compound solution containing Pb, Zr, Ti or the like, lifting it at approx. 5∼20cm per one minute into the atmosphere, then drying it at room temperature, and further heat-treating it at 400∼1000°C.