| 摘要 |
PROBLEM TO BE SOLVED: To avoid frequency deviation after adjustment and attain miniaturization by forming a continuous conductive film with both gaps included while applying voltage to a set of exciting electrodes on one principal plane of a piezoelectric piece, dividing the conductive film with the Joule heat of an applied voltage and performing frequency adjustment. SOLUTION: A metal film 5 is formed on exciting electrodes 2b and 3b on one principal plane side of a crystal piece 1 with both gaps included by vacuum evaporation, etc., from the direction of an arrow P. In such a case, vacuum evaporation is continued while a direct current voltage E is applied to the electrodes 2b and 3b. Thus, on the metal film 5, connection by the vacuum evaporation and fusing by Joule heat are continuously repeated. And when the vacuum evaporation is stopped when a resonance frequency measured between terminals B and C reaches a specified value, the metal film 5 becomes a fusing state at voltage E. Then, because frequency adjustment with a balanced type maintained can be performed without connecting the electrodes 2b and 3b in a common manner, the metal film 5 does not have be divided after the frequency adjustment and frequency deviation prevention after the adjustment becomes possible.
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