Abstract
This paper describes theoretical calculations of the electro mechanical coupling factor of the rectangular piezoelectric bimorph vibrator inserted with an elastic plate in several cases. By neglecting the widthward stress as usual, the coupling factor of bending type bimorph was obtained in a simple form, and it was also the same with the twister type bimorph. Exact solution was obtained which takes into consideration the stress in width direction as well as space charge between electrodes and it was compared with the above approximate solution. Further, the coupling factor of the asymmetric type , bimorph was calculated and was compared with that of the symmetric bimorph.
