| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a metal detector detecting an oxide metal in addition to nonferrous metal and a non iron oxide. <P>SOLUTION: A metal detector 100 comprises: a drive coil 105 generating a magnetic field around a passage route R through which a resin passes; a first and a second spiral coils 113 and 117 respectively generating voltages such that a difference between the generated voltages may change when a magnetic material passes through the passage route R according to the magnetic field generated in the drive coil 105; and a third spiral coil 125 formed flat such that a central portion is formed as a passage route R and an impedance change occurs when an oscillation current flows through the passage route R and a conductor passes through the passage route R. The presence or absence of a contamination of metal foreign matter is detected in accordance with the voltage difference occurred in the first and the second spiral coils 113 and 117 and the impedance change occurred in the third spiral coil 125. <P>COPYRIGHT: (C)2012,JPO&INPIT |
