Patent ID: 7845063
Filing Date: 2010-12-07
Classification: H01L,H03B,H03H,H04R,Y10T

Abstract:
1. A method for manufacturing a quartz crystal unit, comprising the steps of: providing a quartz crystal wafer; providing a case having an interior space and a lid; forming a quartz crystal tuning fork resonator having an overall length capable of vibrating in a flexural mode of an inverse phase by etching the quartz crystal wafer to form a quartz crystal tuning fork base, 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 surfaces and opposite side surfaces, and at least one groove having a length formed in at least one of the opposite main surfaces of each of the first and second quartz crystal tuning fork tines, the quartz crystal tuning fork resonator having a fundamental mode of vibration and a second overtone mode of vibration; determining the length of the at least one groove formed in the at least one of the opposite main surfaces of each of the first and second quartz crystal tuning fork tines and the overall length of the quartz crystal tuning fork resonator so that a series resistance R disposing an electrode on at least one of the opposite side surfaces of each of the first and second quartz crystal tuning fork tines so that the electrode disposed on the at least one of the opposite side surfaces of the first quartz crystal tuning fork tine has an electrical polarity opposite to an electrical polarity of the electrode disposed on the at least one of the opposite side surfaces of the second quartz crystal tuning fork tine; housing the quartz crystal tuning fork resonator in the interior space of the case; and connecting the lid to the case after the housing step.