| 摘要 |
PROBLEM TO BE SOLVED: To obtain accurate relative permeability by accurately obtaining magnetic field information over from a low-frequency band to a high-frequency band. SOLUTION: A magnetic field generating coil 14 generates a nearly uniform alternating current magnetic field with the alternating current from a high-frequency power source 18. A printed board 20 having an annular conductive pattern 22 is arranged in the magnetic field generating coil 14. A through hole 26 is provided in a part of the printed board 20 inside the conductive pattern 22, and a gap 24 is provided on the way to the conductive pattern 22. An electro-optical element 28 formed into a rectangular parallelopiped is inserted into the gap 24 of the conductive pattern 22. After the laser beam from a laser beam source passes the electro-optical element 28, a photo-receiver detects the laser beam. COPYRIGHT: (C)2004,JPO
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