Single crystal transducers for medical imaging applications

Many researchers have focused on growing large relaxor single crystal compositions with high electromechanical properties and optimizing the crystal cuts for best properties. In this work manufacturing issues for fabricating and optimizing PMN-PT and PZN-PT single crystal transducers for medical imaging applications have been studied. One of the important characteristics studied was the composition variation from lot to lot and within different regions of a single crystal. The presence of inclusions and defects, and their effect on dicing capability of the crystals was looked into. The effect of chipping on the electrical properties of single crystal slivers was also observed. Experiments were conducted using alternate processing routes for cutting slivers with low mechanical strength. The acoustic parameters were determined for transducer modeling. When single crystals replace traditional PZT ceramics in a transducer, a 20-25% bandwidth and 3-5 dB sensitivity improvement can be obtained. The expanded frequency range should allow the single crystal transducers to exhibit significant improvement in image quality.