PIEZOELECTRIC VIBRATOR, LADDER-TYPE FILTER USING THIS PIEZOELECTRIC VIBRATOR AND DOUBLE-MODE PIEZOELECTRIC FILTER

摘要

A piezoelectric vibrator which uses lithium tantalate as a piezoelectric material and of which main vibration is thickness shear vibration. The thickness direction of the vibrator forms angle of 0°±5°. The longitudinal direction of vibrator lies, with the X-axis used as a rotation axis, in direction n +57° ±2° clockwise from the Y-axis of the single crystal. A ratio L / H of the length L of the vibrator to the thickness H is not less than 15. A ratio Le / H of the length Le of the exciting electrode to the thickness H of the vibrator element portion is 3 - 6. Accordingly, a vibrator having improved temperature characteristics and a large Q is realized.