| 摘要 |
PROBLEM TO BE SOLVED: To detect a magnetic member with a further simple structure, and to inconspicuously and easily form the magnetic member on a member subjected to mounting. SOLUTION: When a form with a magnetic tag is brought into an area where an alternating magnetic field is generated by drive of an exciting coil with a driving current of a specified frequency by an exciting device 10, the magnetic member included in the magnetic tag causes magnetostrictive vibration by the alternating magnetic field. A frequency measurement processing part 24 measures the frequency characteristic by FFT on the basis of a magnetic field change detected by a detection coil. A frequency characteristic storage part 26 preliminarily stores frequency characteristics of the magnetic member to be included in the magnetic tag. A magnetic member detection processing part 28 compares a reference frequency characteristic stored in the storage part 26 with the measured frequency characteristic from the processing part 24. The presence of a characteristic pattern appearing in the reference frequency characteristic in the measured frequency characteristic is confirmed, whereby the magnetic tag is detected. COPYRIGHT: (C)2004,JPO&NCIPI |
