Electromagnetic induction type inspection device and method

摘要

Any inspection object regardless of material can easily be inspected or discriminated with high accuracy and high sensitivity by being placed in a magnetic field generated by applying an alternating current to an exciting coil (21) and detecting changes of voltage level and phase of electromotive force induced by a detection coil unit (22). The discrimination of the inspection object (90) is performed on the basis of a DC voltage value with respect to a standard specimen (91) and a phase differential voltage value with respect to a phase difference between the phase of a voltage signal from the detection coil unit (22) and the phase of the exciting current to the exciting coil (21).