| 摘要 |
PURPOSE:To suppress effectively all higher harmonic by forming the piezo-electric plate of a piezo-electric vibrator into a parallelogram and by setting the ratio of the length of the long side to the length of the short side and one of angles made by these sides to specific values respectively. CONSTITUTION:On respective graphs where ratio b/a of long side (a) to short side (b) of a parallelogram-shaped piezo-electric plate and one angle theta of angles made by long side (a) and short side (b) are horizontal axes and ratio dB of the antiresonance resistance to the resonance resistance is the vertical axis, when lines A and A', lines B and B', lines C and C', lines D and D', and lines E and E' are shown as fundamental vibration 455kHz, tertiary higher harmonic 1.2MHz, fifth-degree higher harmonic 2.0MHz, outline vibration 650kHz, and bending vibration 300 kHz, respectively, almost all spurious vibration is suppressed effectively for side ratio b/a of approximately 0.7-0.98 and angle theta of approximately 75-89 deg.. Consequently, all higher harmonic is suppressed effectively if relationship between the long side and the short side of the parallelogram-shaped piezo-electric plate is set to values above. |
