Modeling and optimum design of transducers for a tactile screen

A theory for electromechanical transducers made of piezoelectric ceramic and metal layers vibrating in flexure is formulated and studied. Rules for choosing the dimensions of the piezoelectric transducer for the tactile screen used to transfer information to the fingertip in the OPTACON, (OPtical-to-TActile-CONverter) are obtained. Motion of the transducer, either with or without mechanical load, can be factored into two terms. One is an electromechanical factor which depends primarily on the ratio between the piezoelectric ceramic thickness and the metal vane thickness. The other is a mechanical factor independent of the thickness ratio. The total thickness and type of transducer are determined by the mechanical output requirement and available drive voltage. With these set, the ratio of ceramic to metal thicknesses can be optimized for minimum power consumption.