Development of a 1.5D, 1536 element ultrasonic array for use with integrated electronics

A 1536 element, 1.5D, curved linear array was designed to be incorporated into a probe containing integrated beamforming, front end and drive electronics as part of a DARPA initiative on portable battlefield medical diagnostic equipment. Phase aberration correction strategies employed by the ultrasound system require acoustic element performance provided by the more demanding phased array element type. Signal-to-noise (SNR) improvement strategies employed by the probe-mounted ultrasound system further complicate the probe construction. The selected array architecture, whereby the final array assembly is formed by assembling eight autonomous 192 element subarray assemblies, is discussed(1). Heat transfer problems encountered when combining active electronics with an ultrasound array in a probe handle are quantified, and a design strategy to manage them is presented. An indium flex lead plating process is presented. Finally, a parasitic effect caused by wraparound electrodes, discussed previously(2), is presented briefly again because of its importance in large element count array construction.