Abstract: A quartz crystal unit comprising a case having an interior space and a mounting portion in the interior space, and a quartz crystal resonator having a base portion and first and second vibrational arms, the quartz crystal resonator being vibratable in a flexural mode, a capacitance ratio r1 of a fundamental mode of vibration of the quartz crystal resonator being less than a capacitance ratio r2 of a second overtone mode of vibration thereof, a mounting arm protruding from the base portion and extending in a common direction with at least one of the first and second vibrational arms, the mounting arm being mounted on the mounting portion of the case, an electrode being disposed on a surface of the mounting arm and a surface in the interior space of the case, the electrode disposed on the surface of the mounting arm being connected to the electrode disposed on the surface in the interior space of the case.

Abstract: An electronic apparatus comprises a display portion and at least one oscillating circuit comprising an amplifier, at least one resistor, a plurality of capacitors, and a unit having a case and a resonator. The resonator is vibratable in a flexural mode and has first and second vibrational arms, and at least one groove is formed in at least one of opposite main surfaces of each of the first and second vibrational arms, and at least one mounting arm protrudes from the base portion and extends in a common direction with at least one of the first and second vibrational arms. An output signal of the at least one oscillating circuit comprising the resonator is a clock signal for use in operation of the electronic apparatus to display time information at the display portion.

Abstract: An electronic apparatus comprises at least one quartz crystal oscillator comprised of a quartz crystal oscillating circuit having a quartz crystal resonator, an amplifier, at least one resistor, and capacitors. The quartz crystal resonator comprises a quartz crystal tuning fork resonator having a quartz crystal tuning fork base, quartz crystal tuning fork tines connected to the quartz crystal tuning fork base, and at least one groove formed in at least one of opposite main surfaces of the quartz crystal tuning fork tines. A length of the at least one groove formed in at least one of the opposite main surfaces of the quartz crystal tuning fork tines is within a range of 40% to 80% of a length of the quartz crystal tuning fork tines.

Abstract: In a method for manufacturing quartz crystal unit, a quartz crystal oscillator and an electronic apparatus, the method comprises the steps of forming at least triple and in different steps a quartz crystal tuning fork resonator having a frequency of oscillation of a fundamental mode of vibration, the quartz crystal tuning fork resonator having a quartz crystal tuning fork base and first and second quartz crystal tuning fork tines each connected to the quartz crystal tuning fork base, each of the first and second quartz crystal tuning fork tines having a first main surface and a second main surface opposite the first main surface, and a first side surface and a second side surface opposite the first side surface; providing a case having a mounting portion and an open end; providing a lid for covering the open end of the case; mounting the quartz crystal tuning fork resonator on the mounting portion of the case; and connecting the lid to the case to cover the open end thereof.

Abstract: In an electronic apparatus comprising a digital display portion and first and second oscillators comprising first and second oscillating circuits, each of the first and second oscillating circuits having a resonator, an amplifier, a plurality of capacitors, and at least one resistor, a mode of vibration of the resonator of the first oscillating circuit being the same as that of the resonator of the second oscillating circuit, an output signal being output from each of the first and second oscillating circuits, the output signal of one of the first and second oscillating circuits being a clock signal for use in operation of the electronic apparatus to display time information at the digital display portion.

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 and first and second quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. The quartz crystal tuning fork resonator has a piezoelectric constant e?12 within a range of 0.12 C/m2 to 0.19 C/m2 in the absolute value to drive the quartz crystal tuning fork resonator. 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 disposed on the side surfaces of the first quartz crystal tuning fork tine have an electrical polarity opposite to an electrical polarity of the electrodes disposed on the side surfaces of the second quartz crystal tuning fork tine. The quartz crystal tuning fork resonator is mounted on a mounting portion of a case.

Abstract: A piezoelectric crystal tuning fork resonator comprises a tuning fork base and a plurality of tuning fork tines connected to the tuning fork base, each of the tuning fork tines having opposite main surfaces and side surfaces, a groove having a plurality of stepped portions being formed in at least one of the opposite main surfaces of each of the tuning fork tines, a plurality of first electrodes being disposed on the stepped portions of the groove in at least one of the opposite main surfaces of each of the tuning fork tines, a plurality of second electrodes being disposed on the side surfaces of each of the tuning fork tines, the piezoelectric crystal tuning fork resonator comprising three electrode terminals and each of the three electrode terminals having a different electrical polarity.

Abstract: A resonator comprises a base portion and a plurality of vibrational arms connected to the base portion and vibratable in a flexural mode. An electrode is disposed on at least one of opposite side surfaces of each of the vibrational arms so that a capacitance ratio r1 of a fundamental mode of vibration of the resonator is less than a capacitance ratio r2 of a second overtone mode of vibration thereof. A groove is formed in at least one of opposite main surfaces of each of the vibrational arms, and at least one mounting arm protrudes from the base portion.

Abstract: An electronic apparatus comprises a display portion and a plurality of oscillators, one of which is a quartz crystal oscillator comprising: a quartz crystal oscillating circuit comprising; an amplification circuit and a feedback circuit. For example, the feedback circuit is constructed by a quartz crystal resonator comprising vibrational arms and a base portion, and having novel shape and electrode construction. Also, the quartz crystal resonator is housed in a package. In addition, from a relationship of an amplification rate of the amplification circuit and a feedback rate of the feedback circuit, an output signal of the quartz crystal oscillating circuit having an oscillation frequency of a fundamental mode of vibration for the quartz crystal resonator can be provided with a frequency of high stability.

Abstract: The electronic apparatus comprises a display portion and a quartz crystal oscillator at least, and said electronic apparatus comprises at least two quartz crystal oscillators. Also, each of two quartz crystal oscillators of the at least two oscillators comprises a quartz crystal oscillating circuit having an amplification circuit and a feedback circuit. The feedback circuit is constructed by a flexural mode, quartz crystal tuning fork resonator or a width-extensional mode quartz crystal resonator or a thickness shear mode quartz crystal resonator and for example, the quartz crystal tuning fork resonator comprising tuning fork tines and tuning fork base that are formed integrally, is shown with novel shape and electrode construction. Also, the quartz crystal tuning fork resonator, capable of vibrating in a fundamental mode and having a high frequency stability can be provided with a small series resistance and a high quality factor, even when the tuning fork resonator is miniaturized.

Abstract: A quartz crystal resonator has a quartz crystal tuning fork base and quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. Each of the quartz crystal tuning fork tines has opposite main surfaces, a groove formed in at least one of the main surfaces, and an electrode disposed in the groove formed in at least one of the main surfaces so that a merit value M1 of a fundamental mode of vibration of the quartz crystal tuning fork resonator is greater than a merit value M2 of a second overtone mode of vibration thereof. The merit values M1 and M2 are defined by the ratios Q1/r1 and Q2/r2, respectively, where Q1 and Q2 represent a quality factor of the fundamental mode of vibration and the second overtone mode of vibration, respectively, of the quartz crystal tuning fork resonator and r1 and r2 represent a capacitance ratio of the fundamental mode of vibration and the second overtone mode of vibration, respectively, of the quartz crystal tuning fork resonator.

Abstract: In a method for manufacturing a quartz crystal oscillator, at least one of a chemical etching method, a physical etching method, and a mechanical method is utilized to form a quartz crystal tuning fork resonator having a quartz crystal tuning fork base, quartz crystal tuning fork tines connected to the quartz crystal tuning fork base, a fundamental mode of vibration, and a second overtone mode of vibration each comprised of a flexural mode of an inverse phase. An amplification circuit is provided having at least an amplifier. A feedback circuit is provided having the quartz crystal tuning fork resonator and capacitors. The amplifier of the amplification circuit and the quartz crystal tuning fork resonator and capacitors of the feedback circuit are electrically connected together.

Abstract: In method for manufacturing a quartz crystal tuning fork resonator capable of vibrating in a flexural mode, a quartz crystal wafer is etched in a first etching process to form a quartz crystal tuning fork base and quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. The quartz crystal wafer is etched in a second etching process different from the first etching process to form a groove having stepped portions in at least one of opposite main surfaces of each of the quartz crystal tuning fork tines. First electrodes having a first electrical polarity are disposed on the stepped portions of the grooves of respective ones of the quartz crystal tuning fork tines. Second electrodes having a second electrical polarity opposite to the first electrical polarity are disposed on side surfaces of respective ones of the quartz crystal tuning fork tines.

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: A quartz crystal unit has a quartz crystal tuning fork resonator capable of vibrating in a flexural mode of an inverse phase. The quartz crystal tuning fork resonator has a fundamental mode of vibration, a second overtone mode of vibration, a quartz crystal tuning fork base, and a plurality of quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. A merit value M2 for the second overtone mode of vibration of the quartz crystal tuning fork resonator is less than 30 so that the second overtone mode of vibration thereof is suppressed, the merit value M2 being defined by a ratio Q2/r2, where Q2 and r2 represent a quality factor and a capacitance ratio of the second overtone mode of vibration, respectively, of the quartz crystal tuning fork resonator capable of vibrating in the second overtone mode.

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: An electronic apparatus has a display portion and quartz crystal oscillators having different modes of vibration. Each of the quartz crystal oscillators has a quartz crystal oscillating circuit having a quartz crystal resonator. The quartz crystal resonator of one of the quartz crystal oscillating circuits is a width-extensional mode quartz crystal resonator capable of vibrating in a width-extensional mode. The width-extensional mode quartz crystal resonator has a vibrational portion, connecting portions disposed at ends of the vibrational portion, supporting portions connected to the vibrational portion through the connecting portions, and electrodes disposed on upper and lower surfaces of the vibrational portion. The quartz crystal oscillating circuit having the width-extensional mode quartz crystal resonator outputs a clock signal for operating the electronic apparatus to display time information at the display portion.

Abstract: A quartz crystal unit has a quartz crystal tuning fork resonator capable of vibrating in a flexural mode, a case for housing the quartz crystal tuning fork resonator, and a lid for covering an open end of the case. The quartz crystal tuning fork resonator has a tuning fork base, a pair of tuning fork tines connected to the tuning fork base, a series of grooves each formed on opposite main surfaces of each of the tuning fork tines, and a series of electrodes each disposed in a respective one of the grooves. When W and W2 represent a width of each tuning fork tine and a width of at least one of the grooves formed in the tuning fork tines, respectively, W2 is within a range of 0.03 mm to 0.12 mm, and a ratio (W2/W) is greater than 0.35 and less than 1.

Abstract: A piezoelectric quartz crystal resonator has a vibrational portion, connecting portions integrally connected to respective ends of the vibrational portion, support portions integrally connected to the vibrational portion through the connecting portions, and electrodes disposed opposite each other on upper and lower surfaces of the vibrational portion. The piezoelectric quartz crystal resonator vibrates in a width-extensional mode and has a cutting angle in the range of one of xztw(−20° to +°)/(−10° to +10°) and xzwt(−10° to +10°)/(−20° to +20°).

Abstract: A quartz crystal unit, its manufacturing method and a quartz crystal oscillator are illustrated. In particular, the quartz crystal unit and the quartz crystal oscillator having a width-extensional mode quartz crystal resonator comprising a vibrational portion, connecting portions and supporting portions are illustrated with a cutting angle and electrode construction, which provides a high frequency and a high electro-mechanical transformation efficiency, even when the resonator is miniaturized. As a result of which the miniature quartz crystal unit and the quartz crystal oscillator may be provided with a zero temperature coefficient, a small series resistance R1 and a high quality factor Q. That is, these are accomplished by the cutting angle, the electrode construction and a large piezoelectric constant of the width-extensional mode quartz crystal resonator.