PURPOSE: To reduce the waste of a metal and to attain a big change of frequency in a short time by forming a metallic film of the tip part of a tuning fork type crystal oscillator by a plating process and changing the weight of the metallic film to control the frequency of the crystal oscillator.
CONSTITUTION: A metallic film 20 for controlling frequency is formed by an electroplating process and photolithography on frequency control parts 3' and 7' which are electrically connected to main electrode surfaces 3 and 7 of a crystal oscillator via connection parts 3" and 7" respectively. Application of the electroplating process reduces the quantity of metal used for plating in comparison with a vapor deposition process. Thus a desired film thickness between several hundred and 5μm is obtained in a short time.
ISHIHARA MINORU
MATSUDO HIDEAKI
