PIEZOELECTRIC VIBRATOR, FILTER USING THE SAME AND METHOD OF ADJUSTING PIEZOELECTRIC VIBRATOR

摘要

PROBLEM TO BE SOLVED: To provide a piezoelectric vibrator capable of reducing change of resonance frequency due to the warp of the piezoelectric vibrator by adopting a structure in which the polarization direction of a piezoelectric board is directed in the thickness direction and a laminated structure is formed between the piezoelectric board and a dielectric film. SOLUTION: The piezoelectric vibrator has the laminated structure in which silicon oxide film 3 serving as the dielectric film and having approximately the same thickness is provided on both of the main surfaces of the piezoelectric board 1. In such a structure, the difference of internal stress to be applied to the piezoelectric board 1 and the dielectric films caused by the difference of long-term stress relaxation becomes smaller and the warp is made small to the utmost since the dielectric films exist on both of the main surfaces of the piezoelectric board 1. Consequently, the piezoelectric vibrator has an advantage that the change of the resonance frequency of the piezoelectric vibrator due to the warp of the piezoelectric vibrator is made small. COPYRIGHT: (C)2004,JPO