| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To discriminate a human body from a water drop or the like other than the human body, using a capacitance type proximity sensor to detect surely the approach of the human body. <P>SOLUTION: An outer electrode 2a is arranged in a closed side of a door 1, an inner electrode 2b is arranged in an opened side thereof, the outer electrode is connected to a differential circuit 6 via a waveform formation circuit 5, the inner electrode is also connected to the differential circuit, and an output voltage Vc corresponding to a difference between potentials Va, Vb of the both electrodes is input to a determination circuit 7. The determination circuit determines the approach of the human body when the voltage Vc comes to a threshold value Vd or more. A pair of electrodes are brought respectively into a non-grounding condition, one thereof is made to serve as a charged electrode charged with an input of an amplification signal from an amplification circuit, the other is made to serve as a detection electrode receiving a charge from the charged electrode by a capacitor action generated with respect to the charged electrode, and the object (human body) generating a route to the ground is thereby discriminated from the object (water drop or the like) having no direct route thereto, so as to prevent the water drop from being erroneously detected when detecting the approach of the human body. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
