ADJUSTABLE PIEZOELECTRIC CERAMIC RESONATOR

摘要

PURPOSE: To improve the responding speed of an adjustable piezoelectric ceramic resonator by improving the adjusting speed of the adjustable piezoelectric ceramic resonator corresponding to the re-orientation of a domain in the whole volume of a sound guiding element and the threshold switch of a resonant frequency numerical value. CONSTITUTION: Signal electrodes 2 and 3 are given to mutually confronting surfaces vertical to the polarization directions of the sound guiding element 1 of the piezoelectric ceramic material of a parallelopiped such as SbSI and control electrodes 4 and 5 are provided for side surfaces vertical to these surfaces to give the output of DC power source 6 to be controlled and to give a signal voltage source 7 to the electrodes 2 and 3. The element 1 is provided with layers 8 and 9 which are symmetrically uniform with respect to a plane 12 parallel with the depositing surfaces of the electrodes 2 and 3. The surface finishing efficientγof the element 1, the electronic work functional differenceΔA between the piezoelectric ceramic material 1 and the electrodes 2 and 3, the electronic charge (q) and the contact potential differenceϕbetween the layers 8 and 9 are selected to satisfy the given relation, and A1 is added to an ion density grater than the charge density value for shielding the polarization of the layers of the sound guiding element to provide the regions 13 and 14 adjacent to the control electrodes 4 and 5 where the density of structurally defective zone is not less than 10<23> 1/m<3> . At this time the re-orientation of the area of the element is quickened by small external disturbance to improve the responsiveness of the piezoelectric ceramic element.