Method for manufacturing electronic apparatus

A method for manufacturing an electronic apparatus having a display portion for displaying time information and at least one quartz crystal oscillator comprised of a quartz crystal oscillating circuit having an amplification circuit and a feedback circuit, the method comprising the steps of:

• forming by at least one of a chemical etching method, a physical etching method, and a mechanical method a 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 and having a first main surface and a second main surface opposite the first main surface, the quartz crystal tuning fork resonator having a fundamental mode of vibration and a second overtone mode of vibration each comprised of a flexural mode of an inverse phase, a series resistance R1 of the fundamental mode of vibration, a series resistance R2 of the second overtone mode of vibration, and at least one groove having a plurality of stepped portions including a first stepped portion and a second stepped portion opposite the first stepped portion in the width direction, and a third stepped portion connecting the first stepped portion to the second stepped portion formed in at least one of the first and second main surfaces of each of the first and second quartz crystal tuning fork tines;
• providing the amplification circuit having a CMOS inverter, a feedback resistor, a negative resistance −RL1 for the fundamental mode of vibration of the quartz crystal tuning fork resonator, and a negative resistance −RL2 for the second overtone mode of vibration thereof;
• providing the feedback circuit having the quartz crystal tuning fork resonator, a plurality of capacitors and a drain resistor;
• and
• electrically connecting the quartz crystal tuning fork resonator to the CMOS inverter and the feedback resistor of the amplification circuit and to the capacitors and the drain resistor of the feedback circuit;
• wherein a ratio |−RL1|/R1 is greater than 2|−RL2|/R2−1, where |−RL1| represents an absolute value of the negative resistance of the fundamental mode of vibration of the amplification circuit and |−RL2| represents an absolute value of the negative resistance of the second overtone mode of vibration of the amplification circuit;
• wherein a merit value M1 of the fundamental mode of vibration of the quartz crystal tuning fork resonator is greater than a merit value M2 of the second overtone mode of vibration thereof, the merit values M1 and M2 being 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;
• and
• wherein an output signal of the quartz crystal oscillating circuit is a clock signal for use in operation of the electronic apparatus to display time information at the display portion, the clock signal having an oscillation frequency of the fundamental mode of vibration.