FLEXIBLE ELECTROMAGNETIC PROBE ARRAYS

THE FLEXIBLE EDDY-CURRENT PROBE ARRAY CONCEPT, DEVELOPED BY FAILURE ANALYSIS ASSOCIATES , HAS INTRODUCED A NEW APPROACH TO EDDY-CURRENT TESTING. COVERAGE OF THE TEST AREA CAN BE ACCOMPLISHED, WITHOUT SCANNING, BY PLACING AN ARRAY OF PROBES, FABRICATED ON A THIN FLEXIBLE SUBSTRATE, AGAINST THE TEST SURFACE AND ELECTRONICALLY MULTIPLEXING THROUGH THE ARRAY ELEMENTS IN A SELECTED SEQUENCE. THE GOAL OF THIS PROJECT IS TO ADVANCE THE FLEXIBLE EDDY-CURRENT ARRAY CONCEPT TO A POSITION OF PRACTICAL UTILIZATION. THE PRESENT LIMITATIONS OF THE INNOVATION ARE INSUFFICIENT RESOLUTION AND COVERAGE; CURRENT FABRICATION TECHNOLOGY DOES NOT ALLOW FOR SUFFICIENTLY SMALL PROBE ELEMENTS TO BE PACKED WITH SUFFICIENT DENSITY TO PRODUCE THEREQUIRED RESOLUTION AND COVERAGE. THE APPLICATION OF HOLOGRAPHIC INVERSION OF THE DATA OBTAINED FROM STACKED, STAGGERED ARRAYS WILL BE EXPLORED IN ORDER TO IMPROVE THE RESOLUTION. A CLOSER PACKING OF THE ELEMENTS IS OBTAINED BY A MATRIX ELECTRICAL INTERCONNECTION SCHEME. THIS INVOLVES A MATRIX INVERSION OPERATION TO EXTRACT THE INDIVIDUAL ELEMENT RESPONSE FROM THE MIXED SIGNAL OF THE ENTIRE ARRAY. THE ALGORITHMS DEVELOPED IN THE COURSE OF THIS PROJECT WILL BE INCORPORATED INTO SOFTWARE THAT WILL RUN ON A PC-BASED EDDY-CURRENT INSTRUMENT.