| 摘要 |
PURPOSE:To adjust accurately a frequency into the allowable range of a rated resonance frequency by subjecting piezoelectric vibrators, whose frequencies are outside the upper limit value and the lower limit value of the rated resonance frequency, to the first fine frequency adjustment from one frequency region to the other frequency region and subjecting these piezoelectric vibrators to the second fine frequency adjustment together with piezoelectric vibrators whose frequencies are included in the other frequency region from the first. CONSTITUTION:A piezoelectric vibrator 4 consists of a piezoelectric substrate 1 chipped from a wafer into a stripe shape and a pair of exciting electrodes 2a and 2b which are arranged to face main surfaces 1a and 1b facing each other of the substrate 1. In the first frequency adjustment, an insulating film which has 4,000-8,000Angstrom thickness and consists of an SiO2, Si3N4, or the like is stuck uniformly to all vibrators 4 requiring adjustment without observing resonance frequencies. Next, piezoelectric vibrators 4 whose frequencies are moved from the first frequency region I to the second frequency region II are subjected to the second frequency adjustment, where frequencies are adjusted into the allowable range of a rated resonance frequency F0, together with piezoelectric vibrators 4 whose frequencies are included in the second frequency region from the first. In this frequency adjustment, four edge lines 5a-5d forming longer sides of the stripe-shaped substrate 1 are chamfered. |
