| 摘要 |
PROBLEM TO BE SOLVED: To provide a meandering coil type electromagnetic ultrasonic transducer in which sensitivity is high and random noise is reduced and which is hardly broken. SOLUTION: In the meandering coil type electromagnetic ultrasonic transducer comprising a meandering coil for creating an AC magnetic field and a magnet for forming a magneto-static field, linear circuits composed of conductive materials are cyclically formed on one side of an insulating sheet and they are coupled by a conductive material to use a compound meandering sheet coil wherein a plurality of meandering coils are formed at equal intervals of linear portions parallel to one side of one insulating sheet. Otherwise, a plurality of compound meandering sheet coils are overlapped to use a multilayer compound meandering sheet coil coupling them by a conductive external lead wire. Otherwise, a metal sheet or alloy sheet having an electric resistance modulus greater than 40×10<SP>-6</SP>Ωcm and having thickness of≥0.01mm and≤1mm is provided on a surface of the meandering sheet coil at a side of a material to be measured, the meandering sheet coil is protected and furthermore, a ground side terminal of the meandering sheet coil is coupled to the metal sheet or alloy sheet by a conductive material. COPYRIGHT: (C)2005,JPO&NCIPI
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