Piezoelectric resonant part and method of manufacturing the same

摘要

A piezoelectric resonant part includes a piezoelectric substrate having first and second opposed main surfaces, electrode patterns formed on the main surfaces; and protective substrates bonded to respective ones of the main surfaces of the piezoelectric substrate via adhesive layers to form a laminate. Each of the adhesive layers comprising a first layer made of a soft adhesive whose Shore hardness is less than D60 and a second layer made of a hard adhesive whose Shore hardness is more than D60. External electrodes are formed on exposed surfaces of the piezoelectric resonant part. Only the second adhesive layers are exposed in the areas where the external electrodes are located such that the external electrodes do not contact the relatively soft first adhesive layers. The piezoelectric resonant part is made by forming a respective first adhesive layer on a main surface of each of the protective substrates and then forming a respective second adhesive layer on each of the first layers. The protective substrates are then laminated onto respective main surfaces of the piezoelectric substrate with the second layers abutting the main surfaces of the piezoelectric substrate.