| 摘要 |
PURPOSE:To vary the degree of the frequency coupling and thus to increase Q by securing the different coarseness for the surface part of the piezoelectric pole positioned between several pairs of electrodes of the multiple mode oscillator from the coarseness of the surface of other plate face parts. CONSTITUTION:Electrodes 12 and 12' plus 13 and 13' opposing to each other are formed on both surfaces of piezoelectric plate 31 of the multiple mode oscillator which operates in the thickness shear vibration or the thickness vibration, and the coarseness of only the surface of plate face part 32 is finished to the fixed lapping for plate 31 positioned between the two pairs of electrodes. While the surface of other plate face parts excepting part 32 is finished into the mirror surface to secure the different coarseness between part 32 and other parts. Thus the coupling degree of the frequency can be varied thus to increase the value of Q within the band width. |
