Polyimide backed 40-MHz PVDF transducers

Single-element focused PVDF transducers are widely used for high-frequency (> 30 MHz) ultrasound imaging because of their broad bandwidth (BW) and ease of fabrication. A method of fabricating high-frequency transducers (both single element and annular arrays) using a copper-clad polyimide (CCP) film epoxy-bonded to PVDF is presented here. To validate this fabrication technique, single-element PVDF (9-µ mt hick) transducers and an annular array with five rings were assem- bled. Transducer performance was compared quantitatively by measuring center frequency, fractional -6-dB BW and two-way insertion loss (IL). BW and IL were measured from pulse- echo signals from a quartz plate positioned at the geometric focus. CCP backed transducer B-mode images of mouse embryos, acquired using a custom ultrasound backscatter microscope, were of equivalent quality as standard single element PVDF transducers.