Abstract: The present invention relates to the design of piezoelectric transducer subassemblies and systems primarily intended for medical and dental applications. The invention also provides transducer subassemblies and systems with improved performance and a capability to operate more efficiently in torsional or a combined longitudinal-torsional mode of vibration. The invention enables the size and weight of torsional mode transducers to be reduced. Additionally, the electrical characteristics of these transducer systems are improved, thus enabling the transducer end effector to deliver more power to the operative site.

Abstract: The present invention provides a method of manufacturing piezoelectric transducers that improves performance by reducing the mechanical losses in the component interfaces. The method involves the epoxy impregnation and encapsulation of the components within the piezoelectric stack assembly. Impregnation is achieved by capillary action that results in a chemical bond. The encapsulation method results in an epoxy conformal coating that provides a high degree of protection from harsh operational environments and reduces the risk of high voltage electric breakdown.

Abstract: The present invention relates to methods for velocity control of transducers that can compensate both for age related changes as well as the more immediate changes that occur during operation. In one aspect of the invention, the non-motional reactive current is measured at two predetermined frequencies, one below (Ilf) and one above the resonance frequency (Ihf). A correction factor is calculated from these measured currents is used to maintain a specified value of end effector velocity or displacement. In another aspect of the invention, methods are provided for the detection of secondary resonances that could be indicative of end effector fault conditions.