A low-cost high frame-rate piezoelectric scanning mechanism for high-frequency ultrasound systems

This paper characterizes a low cost high-frequency two dimensional imaging system based on a single-element focused imaging transducer and a novel mechanical scanning mechanism. As previous designs have utilized costly electromagnetic motors, for the mechanical scanning translation, this mechanical scanning mechanism provides a highly simplified alternative. The mechanical scanning mechanism utilizes a single piezoelectric bimorph as the actuating element. Laser Doppler analysis of the transducer motion has shown that transducer deflections greater than 10 mm can be obtained for a large range of frequencies, from 40 to 120 Hz. This, in turn, results in a maximum theoretical frame rate of 240 fps. Peak deflections greater than 20 mm can be obtained at the scanning mechanism resonance (110 Hz). Additionally, an analysis of the transducer phase relative to the input voltage has shown that high phase stability (+/- 1.4 degrees) potentially eliminates the need for position encoders, further reducing the device complexity and cost.