| 摘要 |
PROBLEM TO BE SOLVED: To provide a human body detector for sanitation having a long detection distance and less liable to erroneous detection by making the detector resist being affected by objects surrounding an electrode. SOLUTION: This human body detector is equipped with a detection part and a control part. The detection part is equipped with a tabular first detection electrode with its front side exposed, a tabular second detection electrode with its exposed portion on the front side surrounding the first detection electrode while the area of the exposed portion being different from the area of the first detection electrode, and a tabular shield electrode disposed on the back side of the first and second detection electrodes for surrounding the first and second detection electrodes. The control part is equipped with a shield voltage impression circuit for providing the shield electrode with the same potential as the first and second detection electrodes have, first and second capacitance detection circuits for severally detecting/amplifying earth capacitances formed by the first and second detection electrodes to generate voltage outputs, and a detection circuit for generating output voltage signals based on differences between the respective voltage outputs. This detector is placed at the backside of a nonmetallic member of sanitation with the front side of the detection part directed toward the front of the nonmetallic member. COPYRIGHT: (C)2007,JPO&INPIT |
