| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus and method for electromagnetic ultrasonic wave inspection capable of detecting an ultrasonic signal obtained from a defect in a specimen at a high S/N ratio. SOLUTION: The planar coil 12 under a magnet 11 can translationally move together with a magnet, and rotate by an arbitrary angle in the plane parallel to a specimen 13. When an AC current flows to the coil 12, an eddy current is generated in the surface layer of the specimen, and the direction is inverted at the same period as that of the current flowing to the coil 12. The eddy current is mutually acted with the magnetic field generated in the specimen by the magnet 11, a Lorentz's force periodically changing at the part of the specimen where the eddy current flows to generate ultrasonic wave. Since the deflecting direction of the wave depends upon the direction of the coil 12, the deflecting direction of the wave generated in the specimen can be controlled by rotating the coil 12 around the central axis parallel to a z-axis. |
