| 摘要 |
<p>A piezoelectric vibration device using the thickness system vibration used for communication equipment, etc. The device is provided with weight reducing sections (231 and 232) or weight adding sections at parts where an anharmonic overtone mode is relatively strongly excited and which are at least in the vicinity of the outer periphery of an input electrode (21) and a output electrode (22) or a common electrode (23). The total area of the input and output electrodes (21 and 22) is made smaller than the area of the common electrode (23) and the weight reducing or adding sections (231 and 232) are extended to part of the common electrode (23) facing the electrodes (21 and 22). It is preferable to make the thickness of the common electrode (23) formed on one main surface of a quartz plate (1) two to ten times as large as those of the input and output electrodes (21 and 22) formed on the other main surface of the plate (1). The electrodes are made of silver, gold, or a metal composed mainly of gold or silver. Therefore, a piezoelectric vibration device which can suppress the spurious vibration mode generated near the principal vibration and has excellent and wide-band pass band characteristic and an excellent guaranteed damping amount characteristic on the outside of the pass band is obtained. <IMAGE></p> |
