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Abstract

In a method for manufacturing a quartz crystal unit, a quartz crystal tuning fork resonator is formed by etching a quartz crystal wafer to form a id='REI-00001' date='20150623' quartz crystalid='REI-00001' tuning fork base, id='REI-00002' date='20150623' quartz crystalid='REI-00002' tuning fork tines connected to the id='REI-00003' date='20150623' quartz crystalid='REI-00003' tuning fork base, and a groove having stepped portions in at least one of opposite main surfaces of each of the id='REI-00004' date='20150623' quartz crystalid='REI-00004' tuning fork tinesid='REI-00005' date='20150623' . Aid='REI-00005' id='REI-00006' date='20150623' , and by disposing a id='REI-00006' first electrode id='REI-00007' date='20150623' is disposedid='REI-00007' on at least one of the stepped portions id='REI-00008' date='20150623' of each of the groovesid='REI-00008' and a second electrode id='REI-00009' date='20150623' is disposedid='REI-00009' on id='REI-00010' date='20150623' each of side surfacesid='REI-00010' id='REI-00011' date='20150623' at least one side surface id='REI-00011' of each of the id='REI-00012' date='20150623' quartz crystalid='REI-00012' tuning fork tines. id='REI-00013' date='20150623' A frequency of oscillation of the quartz crystal tuning fork resonator is adjusted at least twice and in different steps. The quartz crystal tuning fork resonator is then mounted in a case and an open end of the case is covered with a lid.id='REI-00013' id='REI-00014' date='20150623' An overall length of the resonator and a length of the groove are determined so that a series resistance R₁ of a fundamental mode of vibration of the resonator is less than a series resistance R₂ of a second overtone mode of vibration thereof or less than a series resistance R₃ of a third overtone mode of vibration thereof. id='REI-00014'

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First Claim