Patent ID: 8122587

Claim:
A method for manufacturing a quartz crystal unit having a quartz crystal tuning fork resonator, comprising the steps of: adjusting an oscillation frequency of a quartz crystal tuning fork resonator vibratable in a flexural mode of an inverse phase and having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines connected to the quartz crystal tuning fork base, each of the first and second quartz crystal tuning fork tines having opposite main surface and opposite side surfaces; forming at least one groove in each of the two of the opposite main surfaces of each of the first and second quartz crystal tuning fork tines; disposing an electrode on a surface of the at least one groove formed in each of the two of the opposite main surfaces of each of the first and second quartz crystal tuning fork tines and an electrode on each of two of the opposite side surfaces of each of the first and second quartz crystal tuning fork tines so that the electrode disposed on the surface of the at least one groove formed in each of the two of the opposite main surfaces of the first quartz crystal tuning fork tine is connected to the electrode disposed on each of the two of the opposite side surfaces of the second quartz crystal tuning fork tine and the electrode disposed on the surface of the at least one groove formed in each of the two of the opposite main surfaces of the second quartz crystal tuning fork tine is connected to the electrode disposed on each of the two of the opposite side surfaces of the first quartz crystal tuning fork tine, the quartz crystal tuning fork resonator having a series resistance R 1 of a fundamental mode of vibration less than a series resistance R 2 of a second overtone mode of vibration; mounting the quartz crystal tuning fork resonator on a mounting portion of a case; and connecting a lid to the case to cover an open end of the case.