Multi-dimensional ultrasonic array interconnect

Abstract

An ultrasonic transducer array has a piezoelectric ceramic layer that is separated in a longitudinal direction into n transducer groups. Each group is separated in a transverse direction into m elements. A double-sided flex circuit has a flexible, non-conductive base layer, through which conductive vias extend and are in electrical contact with a respective element. A conductive layer on a bottom side of the flex circuit is divided into a plurality of electrodes, each of which is in electrical contact with a respective one of the elements. For each group, electrically conductive traces connect predetermined ones of the flex circuit electrodes with external driving circuitry, and are located on a top side of the flex circuit. Transducer groups with different numbers of elements are provided, some with 1.5-D operation (with element pairs stimulated via a common trace) and some with 2-D operation (with separate traces for each element). For embodiments with more than three elements per group, the flex circuit includes more than one base layer. The invention also makes it possible at most two traces located on the top side of the flex circuit for each group, measured in the longitudinal direction. In one implementation, each array group was no wider than 300 μm, each trace was at least 50 μm, and the separation between each via and the nearest trace which is not connected to it was at least 75 μm.