| 摘要 |
PURPOSE:To suppress the spurious response due to the thickness oscillation component of a piezoelectric substrate by adding a mass to the piezoelectric substrate and applying damping to the thickness oscillation component, in the piezoelectric resonator having the oscillation mode other than the thickness oscillation mode of the piezoelectric substrate. CONSTITUTION:Electrode films 2 and 3 made of a metal such as Ag are formed on the electrode forming major planes opposing with each other of the piezoelectric substrate 1 of square type having the spread oscillating mode, and a different kind of film 4 is formed over the entire surface by the sputtering on the electrode film 2. In taking the total weight of said electrode films 2, 3 and the different kind film 4 as 2-5% of the weight of the piezoelectric substrate 1, the ratio of peak and notch of the main response is almost constant from zero to some 5% of said weight ratio, while the ratio of peak and notch is small rapidly in the spurious response, when said weight ratio exceeds almost 2%. Thus, the weight ratio is taken to 2-5% where the suppression of the main response is small and the suppression of the spurious response is large. |
