| 摘要 |
PURPOSE:To shut off influences caused by external noise magnetic field by providing a magnetic core, an annular conductive member fixed to contact with both side faces of the magnetic core and a nonmagnetic member fixed to contact with both side faces of above-mentioned conductive member. CONSTITUTION:One edge part of a conductive member 23 is placed on the same plane with a magnetic core 2 and faces opposite to the medium of ceramic members 24, 25. The face of opposite side of the ceramic member 25 is fixed to a leaf spring 5. A coil 12 for recording and reproducing and a coil for erasing are arranged respectively on the legs 26, 27 of the magnetic core 2. In the case where external noise magnetic field is applied in the direction of the face opposite to the medium of the magnetic core 2, noise magnetic field interlinks inside of the annular conductive member 23. In the conductive member 23, induced current that generates a magnetic field in the direction that obstructs change in time of interlinked noise magnetic field is excited, and change of external noise magnetic field is made small. The larger the plate thickness and the smaller the resistivity, the larger the shielding effect by the conductive member 23, and special materials are not necessary. |
