LOW-FREQUENCY VICINITY ELECTROMAGNETIC FIELD DETECTING SENSOR, AND GAME MACHINE

摘要

PROBLEM TO BE SOLVED: To suppress a malfunction of a proximity switch due to the approach of a low-frequency vicinity electromagnetic field.;SOLUTION: A high-frequency oscillation circuit 211 oscillates a high-frequency signal of a band which is close similar to that of a high-frequency oscillation circuit 221; a coil L1 detects an approach of a low frequency vicinity electromagnetic field through voltage induction and to an LC resonance circuit 201 comprised of the coil L1 and a capacitor C1; the resonance frequency is set to be closely similar to a resonance frequency of a resonance circuit 202, comprising a coil L2 and a capacitor C2 in a game ball detector 2. A shielding member 21 opens a part of the coil L1 and conductance of the high-frequency oscillation circuit 211 is set larger than that of the LC resonance circuit 201 by a sensitivity adjusting resistor R1. If there is no low-frequency vicinity electromagnetic field radiation, the oscillation of the high-frequency oscillation circuit 211 is stopped; but if there is the radiation, the high-frequency oscillation circuit 211 is oscillated, and a discrimination circuit 212 detects oscillation of the high-frequency oscillation circuit. The present invention is applicable to game machines.;COPYRIGHT: (C)2011,JPO&INPIT