Modular Fabrication and Assembly of Large 2D Arrays with Interface Asics, Pin-Pmn-Pt Composite, and 3D Printed Backing

Tiled modular 2D ultrasound arrays have the potential for realizing large apertures for novel diagnostic applications. Here we present the results of recent work for fabrication of a tileable 2D array module implemented using a 1-3 composite of high bandwidth PIN-PMN-PT material closely coupled with high voltage CMOS ASICs for buffering and multiplexing functions. The 2D transducer array is supported by a 3D printed conducting and acoustically attenuating interposer backing which links the array to a PCB housing the interface ASICs. A novel low temperature approach for assembly of the acoustic modules to the printed circuit board utilizing conductive adhesive is presented. The fabricated module consists of an array of 6 × 20 elements at 600 μm pitch in azimuth, and 1600 μm pitch in elevation. The combined acoustic electric assembly displayed excellent overall fractional bandwidth of 81% for the functional elements, high element yield of 93%, and had a center frequency of 3.5 MHz, and -20 dB pulse length of 850 ns. The device was interfaced to a Verasonics Vantage 128 ultrasound system using an FPGA controller, and images were acquired using an industry standard tissue mimicking phantom.