Conductive foreign material detecting apparatus

摘要

A conductive foreign material detecting apparatus includes an exciting coil configured to apply an AC magnetic field to a base substance through which the AC magnetic field passes, a magnetic sensor configured to detect a change of the AC magnetic field caused by a conductive foreign material on a surface of the base substance or in the base substance, a noise reduction coil configured to reduce a noise of substantially the same frequency as the AC magnetic field other than the change of the AC magnetic field by generating predetermined magnetic field to the AC magnetic field, and a current controller configured to control a drive current and a phase of the noise reduction coil so as to make the noise of substantially the same frequency as the AC magnetic field other than the change of the AC magnetic field be minimal.