Abstract: A quartz crystal unit has a quartz crystal tuning fork resonator having a thickness within a range of 0.05 mm to 0.18 mm, and at least one groove formed in at least one of opposite main surfaces of each of first and second tuning fork tines so that a length of the at least one groove is within a range of 20% to 78% of an overall length of the resonator and less than 1.29 mm. An electrode is disposed on at least one of a base portion and a surface of the at least one groove so that the electrode of the first tuning fork tine has an electrical polarity opposite to an electrical polarity of the electrode of the second tuning fork tine. The capacitance ratio r2 of a second overtone mode of vibration of the quartz crystal tuning fork resonator is greater than 1500. The quartz crystal tuning fork resonator is housed in a case having an open end, and a lid is connected to the case.

Abstract: A method for manufacturing a quartz crystal unit, comprising the steps of forming a quartz crystal tuning fork shape having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines, a quartz crystal tuning fork resonator having the quartz crystal tuning fork shape, forming at least one groove in at least one of opposite main surfaces of each of the first and second quartz crystal tuning fork tines, determining each of a length of the at least one groove and an overall length of the quartz crystal tuning fork resonator so that a series resistance R1 of a fundamental mode of vibration of the quartz crystal tuning fork resonator is less than a series resistance R2 of a second overtone mode of vibration thereof, housing the quartz crystal tuning fork resonator in a case, connecting a lid to the case, and disposing a metal or a glass in a through-hole of the case.

Abstract: A unit comprises a quartz crystal resonator having a base portion, and first and second vibrational arms, each of the first and second vibrational arms having opposite main surfaces. At least two grooves are formed in at least one of the opposite main surfaces of each of the first and second vibrational arms so that a distance in the width direction of the at least two grooves measured from an outer edge of the one of the at least two grooves to an outer edge of the other of the at least two grooves is less than 0.05 mm.

Abstract: A quartz crystal unit comprises a quartz crystal resonator having an overall length less than 2.1 mm, a base portion, and first and second vibrational arms connected to the base portion. At least one groove is formed in at least one of opposite main surfaces of each of the first and second vibrational arms so that a width of the at least one groove formed in the at least one of the opposite main surfaces of each of the first and second vibrational arms is less than a spaced-apart distance between the first and second vibrational arms. The quartz crystal resonator is housed in a case, and a lid being connected to the case to cover an open end of the case.

Abstract: In a quartz crystal unit, the unit comprising a quartz crystal resonator having a base portion, and first and second vibrational arms connected to the base portion, at least one groove being formed in at least one of opposite main surfaces of each of the first and second vibrational arms, a length of the base portion being less than 0.5 mm and an overall length of the quartz crystal resonator being less than 2.1 mm, at least one mounting arm protruding from the base portion and being formed between the first and second vibrational arms, the at least one mounting arm extending in a common direction with the first and second vibrational arms.

Abstract: A method for manufacturing a quartz crystal unit comprises disposing a metal film on a surface of a quartz crystal wafer, disposing a resist on the metal film, forming a tuning fork shape pattern on the surface, etching the quartz crystal wafer to form a quartz crystal tuning fork shape having a base and first and second tines, forming electrodes on opposite side surfaces of the first and second tines so that the electrode of the first tine has an electrical polarity opposite to an electrical polarity of the electrode of the second tine to form a quartz crystal tuning fork resonator that vibrates in a flexural mode of an inverse phase, removing the resist before forming the electrodes, mounting the tuning fork resonator on a mounting portion of the case, disposing a metal or a glass into a through-hole of the case, and adjusting an oscillation frequency of the tuning fork resonator.

Abstract: A method of manufacturing a quartz crystal unit comprises disposing a metal film on opposite surfaces of a quartz crystal wafer and then etching the wafer to form a two-line tuning fork resonator vibratable in a flexural mode of an inverse phase. A groove is formed in the opposite main surfaces of both tines, and the length of each groove is determined relative to the length of the resonator so that the series resistance of the fundamental mode of vibration of the resonator is less than the series resistance of the second overtone mode of vibration thereof. The resonator is then mounted in case after which the resonant frequency of the resonator is adjusted.

Abstract: A unit comprising a quartz crystal resonator vibratable in a flexural mode and having a base portion including a length less than 0.5 mm, and first and second vibrational arms connected to the base portion, at least one groove being formed in each of two of opposite main surfaces of each of the first and second vibrational arms, and an electrode being disposed 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 vibrational arms 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 vibrational arm has an electrical polarity opposite to an electrical polarity of 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 vibrational arm.

Abstract: In a unit comprising a quartz crystal resonator, a case having a mounting portion, and a lid connected to the case, the quartz crystal resonator having a base portion, and first and second vibrational arms connected to the base portion, at least one groove being formed in at least one of opposite main surfaces of each of the first and second vibrational arms, at least one mounting arm being connected to the base portion having a length L1 less than 0.5 mm and extending in a common direction with at least one of the first and second vibrational arms, the at least one mounting arm being mounted on the mounting portion of the case.

Abstract: A method for manufacturing a quartz crystal unit comprises the steps of forming 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, forming at least one groove having at least three stepped portions in at least one of opposite main surfaces of each of first and second quartz crystal tuning fork tines, disposing an electrode on a surface of one of the at least three stepped portions of the at least one groove and an electrode on one of opposite side surfaces of each of the first and second quartz crystal tuning fork tines, 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, wherein the step of forming the quartz crystal tuning fork base and the first and second quartz crystal tuning fork tines is performed before the step of formin

Abstract: A quartz crystal unit has a quartz crystal resonator, a case for housing the quartz crystal resonator, and a lid for covering an open end of the case. The quartz crystal resonator comprises a quartz crystal tuning fork resonator capable of vibrating in a flexural mode of an inverse phase and having at least one groove, and an electrode is disposed on at least one of opposite side surfaces of each of the first and second quartz crystal tuning fork tines. The quartz crystal tuning fork resonator has a capacitance ratio r2 of a second overtone mode of vibration greater than 1500. The lid is connected to the case through a connecting member to cover the open end of the case.

Abstract: A quartz crystal oscillator has an amplifier, a capacitor, a resistor and a quartz crystal unit comprised of a case, a quartz crystal tuning fork resonator vibratable in a flexural mode and a lid connected to the case. At least one groove with a first surface opposite a first side surface and a second surface connected to the first surface through a third surface is formed in each of first and second main surfaces of each of first and second quartz crystal tuning fork tines. The width of each groove is greater than a distance in the width direction of the groove measured from an outer edge of the groove to an outer edge of the corresponding tuning fork tine. A first electrode is disposed on the first surface of the groove and a second electrode is disposed on the first side surface so that the first electrode has an electrical polarity opposite to the electrical polarity of the second electrode.

Abstract: An electronic apparatus has a display portion, and first and second oscillating circuits each having a quartz crystal resonator, the quartz crystal resonator of each of the first and second oscillating circuits vibrating in a different mode from each other. One of the quartz crystal resonators is a quartz crystal tuning fork resonator having first and second tuning fork tines. Electrodes are disposed on side surfaces of each of the first and second tuning fork tines so that the electrodes of the first tuning fork tine have an electrical polarity opposite to an electrical polarity of the electrodes of the second tuning fork tine. The capacitance ratio r1 of a fundamental mode of vibration of the quartz crystal tuning fork resonator is less than a capacitance ratio r2 of a second overtone mode of vibration thereof. An output signal of the oscillating circuit having the quartz crystal tuning fork resonator is a clock signal used to display time information at the display portion of the electronic apparatus.

Abstract: A method for manufacturing a quartz crystal unit comprises the steps of adjusting an oscillation frequency of a quartz crystal tuning fork resonator that is vibratable in a flexural mode of an inverse phrase and that has first and second quartz crystal tuning fork tines, forming at least one groove in each of two of opposite main surfaces of each of first and second quartz crystal tuning fork tines, disposing an electrode on a surface of the at least one groove formed in each of two of the opposite main surfaces and each of two of opposite side surfaces of each of the first and second quartz crystal tuning fork tines so that the electrodes of the grooves of the first quartz crystal tuning fork tine are connected to the electrodes of the side surfaces of the second quartz crystal tuning fork tine and the electrodes of the grooves of the second quartz crystal tuning fork tine are connected to the electrodes of the side surfaces of the first quartz crystal tuning fork tine, the quartz crystal tuning fork resonat

Abstract: A method for manufacturing a quartz crystal unit comprises the steps of forming a quartz crystal tuning fork resonator having a quartz crystal tuning fork shape, forming at least one groove in at least one of opposite main surfaces of each of first and second quartz crystal tuning fork tines so that a spaced-apart distance between the first and second quartz crystal tuning fork tines is greater than or equal to a width of the at least one groove, determining the dimension of each of the quartz crystal tuning fork shape and the at least one groove so that a capacitance ratio r1 of a fundamental mode of vibration of the quartz crystal tuning fork resonator is less than a capacitance ratio r2 of a second overtone mode of vibration thereof, 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.

Abstract: A quartz crystal unit has a quartz crystal tuning fork resonator that is capable of vibrating in a flexural mode and that has a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines. The quartz crystal tuning fork resonator is mounted on a mounting portion of the case after which the oscillation frequency of the quartz crystal tuning fork resonator is adjusted. The quartz crystal unit comprising the quartz crystal tuning fork resonator has a series resistance R1 of a fundamental mode of vibration less than a series resistance R2 of a second overtone mode of vibration. At least one groove is formed in at least one of opposite main surfaces of each of the first and second quartz crystal tuning fork tines so that a width of the at least one groove is greater than a distance in the width direction of the at least one groove measured from an outer edge of the at least one groove to an outer edge of the corresponding one of the first and second quartz crystal tuning fork tines.

Abstract: A quartz crystal unit comprises a quartz crystal tuning fork resonator capable of vibrating in a flexural mode of an inverse phase and having at least one groove having at least one stepped portion formed in at least one of opposite main surfaces of each of first and second quartz crystal tuning fork tines. An electrode is disposed on the at least one stepped portion of the at least one groove so that the electrode of the first quartz crystal tuning fork tine has an electrical polarity opposite to an electrical polarity of the electrode of the second quartz crystal tuning fork tine. The quartz crystal unit comprising the quartz crystal tuning fork resonator has a capacitance ratio r1 of a fundamental mode of vibration less than a capacitance ratio r2 of a second overtone mode of vibration.

Abstract: A method for manufacturing a quartz crystal unit comprises forming a quartz crystal tuning fork resonator that is capable of vibrating in a flexural mode of an inverse phase and that has a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. An electrode is disposed on each of two of side surfaces of each of the first and second quartz crystal tuning fork tines so that the electrodes of the first quartz crystal tuning fork tine have an electrical polarity opposite to an electrical polarity of the electrodes of the second quartz crystal tuning fork tine, a motional capacitance C1 of a fundamental mode of vibration of the quartz crystal tuning fork resonator being greater than a motional capacitance C2 of a second overtone mode of vibration thereof.

Abstract: A quartz crystal tuning fork resonator has quartz crystal tuning fork tines for undergoing vibration in an inverse phase. Each of the quartz crystal tuning fork tines has a first main surface and a second main surface opposite the first main surface, each of the first and second main surfaces having a central linear portion. The quartz crystal tuning fork tines extend from a quartz crystal tuning fork base. At least one groove is formed in the central linear portion of each of the first and second main surfaces of each of the quartz crystal tuning fork tines. A width of the groove in the central linear portion of one of the first and second main surfaces of each of the quartz crystal tuning fork tines is greater than or equal to a distance in the width direction of the groove measured from an outer edge of the groove to an outer edge of the tuning fork tine.

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 quartz crystal tuning fork base, quartz crystal tuning fork tines connected to the quartz crystal tuning fork base, and a groove having stepped portions in at least one of opposite main surfaces of each of the quartz crystal tuning fork tines. A first electrode is disposed on at least one of the stepped portions of each of the grooves and a second electrode is disposed on each of side surfaces of each of the quartz crystal tuning fork tines. 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.