Abstract: In a quartz crystal unit, the unit comprising a case, and a resonator having a base portion, and first and second vibrational arms, the base portion having a first base portion including a first width, and a second base portion including a second width greater than the first width, each of the first and second vibrational arms having a first vibrational portion including a first width and a first length, and a second vibrational portion including a second width greater the first width and a second length less than the first length, the second base portion being mounted on a mounting portion of the case, at least one groove being formed in at least one of opposite main surfaces of the first vibrational portion of each vibrational arm, and a spaced-apart distance between the second vibrational portions of the first and second vibrational arms being less than a length of the second base portion of the base portion.

Abstract: A resonator comprising a base portion, first and second vibrational arms, and a frame having first, second, third and fourth frame portions, the first and second frame portions extending in a common direction with the vibrational arms, third frame portion being connected to the base portion, the first frame portion being connected to the second frame portion through the third and fourth frame portions, each of the vibrational arms having a first vibrational portion including a first width and a first length, and a second vibrational portion including a second width greater the first width and a second length less than the first length, a groove being formed in at least one of main surfaces of each vibrational arm, and a spaced-apart distance between the second vibrational portions being less than a spaced-apart distance between the first frame portion and the first vibrational portion of the first vibrational arm.

Abstract: In a quartz crystal unit, the unit comprising a quartz crystal tuning fork resonator having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines, each of the first and second quartz crystal tuning fork tines having a first vibrational portion including a first width and a second vibrational portion including a second width greater than the first width, at least one groove being formed in at least one of opposite main surfaces of the first vibrational portion of each quartz crystal tuning fork tine, the first width of the first vibrational portion of each quartz crystal tuning fork tine being greater than 0.03 mm and less than 0.075 mm and the second width of the second vibrational portion of each quartz crystal tuning fork tine being greater than 0.04 mm and less than 0.23 mm.

Abstract: A quartz crystal resonator unit has an overall length less than 2.1 mm and a base portion having a length less than 0.5 mm and a width less than 0.55 mm, vibrational arms, and mounting arms connected to the base portion through connecting portions. Each vibrational arm has a first vibrational portion including a first width and a first length within a range of 0.32 mm to 0.72 mm and a second vibrational portion including a second width greater than the first width and a second length less than the first length. A groove is formed in at least one main surface of the first vibrational portions of the vibrational arms, a width of the groove being less than 0.07 mm and a distance in the width direction of the groove being less than 0.015 mm. A width of the mounting arms is less than 0.45 mm and a width of the connecting portion is less than 0.41 mm.

Abstract: In a quartz crystal unit, the unit comprising a case, a quartz crystal tuning fork resonator and a lid, the resonator having a tuning fork base, and first and second tuning fork tines, each of the first and second tuning fork tines having a first side surface and a second side surface opposite the first side surface, the first side surface of the first tuning fork tine confronting the second side surface of the second tuning fork tine; at least one groove having a plurality of surfaces including a first surface being formed in at least one of first and second main surfaces of each of the first and second tuning fork tines so that only the first surface of the at least one groove is directly opposite the first side surface of the corresponding tuning fork tine and a width of the at least one groove is greater than or equal to 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 tunin

Abstract: In a quartz crystal unit, the unit comprising a quartz crystal resonator having an overall length less than 2.1 mm, and a base portion, and first and second vibrational arms, at least one groove being 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 is greater than or equal to 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 vibrational arms and less than 0.07 mm, at least one metal film for adjusting an oscillation frequency of the quartz crystal resonator being disposed on at least one of the opposite main surfaces of each of the first and second vibrational arms.

Abstract: A quartz crystal unit comprises a quartz crystal tuning fork resonator having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork arms. Each of the first and second quartz crystal tuning fork arms has a first main surface and a second main surface opposite the first main surface, and at least one groove formed in at least one of the first and second main surfaces of each of the first and second quartz crystal tuning fork arms. At least one mounting arm having a width less than 0.45 mm protrudes from the quartz crystal tuning fork base, and the overall length of the quartz crystal tuning fork resonator is less than 2.1 mm.

Abstract: In a method for manufacturing a quartz crystal resonator, the method comprising the steps of: forming a quartz crystal tuning fork resonator having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines; 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 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; and forming a metal film on at least one of the opposite main surfaces of the first and second quartz crystal tuning fork tines so that an oscillation frequency of the quartz crystal tuning fork resonator is lower than 32.768 kHz.

Abstract: In a method for manufacturing a quartz crystal unit, a metal film is formed on a quartz crystal wafer which is then etched to form a quartz crystal tuning fork resonator having first and second tines vibratable in flexural and fundamental modes. A groove is chemically etched in a first main surface of both tines such that a first surface of the groove is opposite a first side surface of the corresponding tine. The width of the groove is greater than a distance in the width direction from the groove first surface to the first side surface of the corresponding tine. An electrode is formed on each groove first surface and on the first side surface of both tines with the electrode on the groove first surface of the first tine having the same electrical polarity as the electrode on the first side surface of the second tine.

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: In a quartz crystal unit, the unit comprising a quartz crystal resonator having an overall length less than 2.1 mm, and a base portion, and first and second vibrational arms, at least one groove being 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 is greater than or equal to 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 vibrational arms and less than 0.07 mm, at least one metal film for adjusting an oscillation frequency of the quartz crystal resonator being disposed on at least one of the opposite main surfaces of each of the first and second vibrational arms.

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 method for manufacturing a quartz crystal resonator, the method comprising the steps of: forming a quartz crystal tuning fork resonator having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines; 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 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; and forming a metal film on at least one of the opposite main surfaces of the first and second quartz crystal tuning fork tines so that an oscillation frequency of the quartz crystal tuning fork resonator is lower than 32.768 kHz.

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: 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.

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, and by disposing 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 at least one side surface 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.

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.