Frequency adjusting method for piezoelectric resonator

PURPOSE: To freely adjust thickness of additional film, to improve the yield, and to reduce the manufacturing cost by forming a mass additional film of a specific epoxy resin on a pair of counter electrodes formed on a piezoelectric substrate or in its vicinity. CONSTITUTION: On both main faces of a piezoelectric substrate 11, a pair of counter electrodes 12a, 13a are formed, and on these counter electrodes or in its vicinity, mass additional films 14a, 14b of a phenol novolak type epoxy resin shown by a formula, which is dissolved by an ethylene chloride compound solvent, and not dissolved by an acetone compound solvent are formed. In this case, in the case thickness of the mass additional films 14a, 14b is too large, the mass additional film is formed again by dissolving and eliminating the mass additional films 14a, 14b by the ethylene chloride compound solvent. In such a way, since the thickness of the mass additional films 14a, 14b can be adjusted freely, the vibration frequency of the piezoelectric substrate 11 can be adjusted freely, and a resonance frequency can be adjusted easily. COPYRIGHT: (C)1993,JPO&Japio