| 摘要 |
PROBLEM TO BE SOLVED: To detect the passing of a game ball while suppressing malfunction of a proximity switch caused by the approach of a low-frequency near electromagnetic field. SOLUTION: A coil L1 detects the passing of a game ball. A high-frequency oscillation circuit 11 includes a detecting coil L1 and oscillates a high frequency. A peak-value setting circuit 13 sets a peak of an oscillation wave generated in the detecting coil L1 to a first prescribed value. A comparator circuit 15-1 uses a second prescribed value set to a lower level than the first prescribed value as a discrimination potential and compares the second prescribed value with the peak value oscillated by the high-frequency oscillation circuit 11 so as to output the comparison result. A comparator circuit 15-2 uses a third prescribed value set to a higher level than the first prescribed value as a discrimination potential and compares the third prescribed value with the peak value oscillated by the high-frequency oscillation circuit 11 so as to output the comparison result. An output circuit 16-1 outputs the comparison result of the comparator circuit 15-1 to the outside. The proximity switch is applicable to a game machine. COPYRIGHT: (C)2011,JPO&INPIT |
