A demountable interconnect system for a 50/spl times/50 ultrasonic imaging transducer array

A novel Pad Grid Array (PGA) system allows microminiature coaxial conductors to be electrically connected to a one-half wavelength, 50/spl times/50 element transducer array suitable for diagnostic ultrasound at 2.5 MHz. In order to achieve the desired one-half wavelength interconnection spacing present at the backing of the transducer module, an intermediary flexible printed circuit and other custom structures provide a transitional architecture between 42 AWG coax and inline interconnect pads at a 300 /spl mu/m spacing. Due to critical alignment requirements, special processes are needed for fabrication and the successful connection of the fine-pitch circuit elements. A conductive anisotropic elastomeric material acts as the medium to effect the final interconnect between the PGA and transducer module. Because the anisotropic medium provides a separable interface, the interconnect system allows repeated connection. Acoustic performance indicates suitability for diagnostic imaging.