| 摘要 |
PURPOSE:To prevent the coupling of vibration between piezoelectric vibrating parts and the attenuation of the piezoelectric vibrating part by providing a recess having a depth being 1/500 of the thickness of a piezoelectric plate or over at least on one side of the piezoelectric plate and between the piezoelectric vibrating parts in a plural type piezoelectric vibrator where >=2 of the piezoelectric vibrating parts formed with an electrode on both sides are provided on the piezoelectric plate. CONSTITUTION:Both resonance frequencies of two single piezoelectric vibrators shown in figure I are denoted as f1, f2, the levels at that time as V1, V2, both the resonance frequencies of the twin piezoelectric vibrator shown in figure II as f1', f2' and the levels at that time as V1', V2', respectively and the relation of DELTAV=¦V1-V1'¦ and DELTAf=¦f1-f1'¦ is obtained. The DELTAV and DELTAf are decreased more as the depth (d) of the recess is deeper in the relation among the DELTAV, DELTAf of the twin piezoelectric vibrator shown in the figure I and the (d mum) of the depth of the recess and the twin piezoelectric vibrator shown in the figure II. Then it is clear from the relating figure that the effect is given when the depth (d) of the recess is >=0.2(mum). That is, the effect is produced when the depth of the recess is at least >=1/500 of the thickness of the piezoelectric plate. |
