| 摘要 |
PROBLEM TO BE SOLVED: To provide a proximity sensor in which a rear side region is made a non-output region and a front side region does not shorten a detection distance. SOLUTION: Electrodes are constituted of a pair of a front side electrode 1 and a rear side electrode 2. An electric circuit serially connects a capacitor 3 by both of the electrodes, a coil 4, a resistor 5, and an oscillation source 6. When a ground body approaches the front side electrode in the front side region and approaches the rear side electrode in the rear side region, capacitance changes and current flowing the resistor changes. A means 11 for measuring voltage of resistor both ends is provided and the frequency (f) of an oscillation AC of the oscillation source is set within a range where a change of measured value in the measurement means is in the reverse direction of an increase and a decrease by an approach in the front side region and an approach in the rear side region. A means 12 for calculating a change amount of the measurement value, a means 13 for determining whether or not an approach is in the front side region in the change amount, and a means 14 for performing output when it is determined that an approach is in the front side region are provided. When the ground body approaches in the front side region, output is performed; and when it approaches in the rear side region, output is not performed. COPYRIGHT: (C)2010,JPO&INPIT |
