@article{oai:kanazawa-u.repo.nii.ac.jp:00009595,
 author = {Yamada, Sotoshi and Nakamura, Kazunori and Iwahara, Masayoshi and Taniguchi, T. and Wakiwaka, H.},
 issue = {5},
 journal = {IEEE Transactions on Maggetics},
 month = {Sep},
 note = {The detection of imperfections (such as disconnections, chipping cracks, nonuniformity in thickness and short-circuit, etc.) on the traces of bare printed circuit board (PCB) using a new high-sensitive eddy-current testing (ECT) probe has been reported in this paper. The ECT technique is composed of planar meander type exciting coil and a new multiple solenoid sensing coil. The image processing method is used to analyze the results. This paper has discussed the structure of the new probe, the characteristics of the measurement technique to inspect high-density PCB with narrow conductor-width. And the possibility of detecting micro-metal ball has been explored., A new application of eddy current testing techniques for investigating trace defects on printed circuit boards is proposed, A test probe consisting of a meander type exciting coil is used to induce eddy currents. The following three experiments are conducted: measuring the induced signal when a circuit trace is cut; measuring the induced signal for a number of traces placed in parallel and with a cut in the centre trace; measuring the induced signal for two back to back right angle traces. The experimental results reveal that it is possible to clearly detect defects and that the signal response obtained is strongly associated with a particular defect pattern. The signals obtained from a high density patterned board have a complicated signal signature and are therefore difficult to interpret. This complexity can be avoided by comparing the signal signature of a known good board with a defective board. The difference signal gives a clear indication of a trace defect.},
 pages = {3325--3327},
 title = {Application of ECT Technique for Inspection of Bare PCB},
 volume = {39},
 year = {2003}
}