PROXIMITY DETECTION SENSOR AND PROXIMITY DETECTION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a proximity detection sensor for performing high-accuracy detection with a circuit structure for computing and outputting a difference in pulse width. SOLUTION: This proximity detection sensor is equipped with a detection electrode 2, a first detection circuit 4 converting a change in capacitance between the detection electrode 2 and ground into a detection pulse signal P1to output it, a reference capacitor 6 charged during a prescribed time period, a second detection circuit 8 converting a change in capacitance of the reference capacitor 6 into a reference pulse signal P2to output it, a trigger signal generation circuit 10 generating a trigger signal TG for charging the detection electrode 2 and the reference capacitor 6 at prescribed time intervals, and a computation circuit 12 for calculating a difference pulse signal P3from the pulse signal P1inputted from the detection circuit 4 and the pulse signal P2inputted from the detection circuit 8. COPYRIGHT: (C)2009,JPO&INPIT