CONDUCTIVE FOREIGN MATERIAL DETECTING APPARATUS

摘要

The present invention relates to a device for detecting a conductive foreign material. The device for detecting a conductive foreign material comprises: an excite coil configured to apply an AC magnetic field to a base material through which the AC magnetic field passes; a magnetic sensor configured to detect change in the AC magnetic field generated by a conductive foreign material on a surface of the base material or the base material; a noise reducing coil configured to reduce noise of frequency actually same as that of the AC magnetic field besides change in the AC magnetic field by generating the predetermined magnetic field for the AC magnetic field; and a current controller configured to control drive current and phase of the noise reducing coil in order to minimize the noise of the frequency actually same as that of the AC magnetic field besides change in the AC magnetic field.