| 摘要 |
PURPOSE:To adjust the frequency to a required reference frequency and to reduce the ternary temperature coefficient by providing a projection being a weight to a tuning fork tip in a tuning fork type coupling crystal vibrator where the bending mode and the torsional mode are combined at the fundamental wave vibration and selecting a specific value for the side ratio T/W (W is the width of the vibrator and T is the thickness). CONSTITUTION:Since the amplitude is maximum at the tuning fork tip when the basic wave vibration is in the bending mode and the torsion mode, a weight 4 is added to the tip of the vibrator 3. As the T/W increases, the ternary temperature coefficient (r) approaches zero. Then the T/W is selected as 0.35-0.85. The T/W halving the conventional (r) is 0.35 and the temperature characteristic is improved remarkably. Moreover, in vibrating the vibrator at the bending mode offering the major vibration, it is sufficient to select the T/W as <0.85. Thus, the frequency change is decreased over a wide temperature range and the tuning fork vibrator is in use, then small size and light weight are attained. Moreover, since the metallic weight arranged at the tip of the tuning fork is removed by a laser, the frequency adjustment is facilitated and the manufacture process number is saved considerably.
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