Patent ID: 8091189
Filing Date: 2012-01-10
Classification: H03B,H03H,H04R,Y10T

Abstract:
1. A method for manufacturing a quartz crystal unit, comprising the steps of: providing a quartz crystal wafer having opposite surfaces; providing a case having a mounting portion; forming in the quartz crystal wafer a quartz crystal tuning fork resonator capable of vibrating 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 surfaces and opposite side surfaces; mounting the quartz crystal tuning fork resonator having an overall length on the mounting portion of the case; adjusting an oscillation frequency of the quartz crystal tuning fork resonator; forming at least one groove having a length in at least one of the opposite main surfaces of each of the first and second quartz crystal tuning fork tines; forming an electrode on a surface 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 so that the electrode formed on the surface of the at least one groove formed in the at least one of the opposite main surfaces of the first quartz crystal tuning fork tine has an electrical polarity opposite to an electrical polarity of the electrode formed on the surface of the at least one groove formed in the at least one of the opposite main surfaces of the second quartz crystal tuning fork tine; and 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 the quartz crystal tuning fork resonator has a series resistance R