| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable a difference of a static electric capacity shown by existence of a sitting man from that shown by no existence of the sitting man to be enlarged owning to the small configuration of an electrode by judging whether a man is sitting on a seat or not on the basis of a pulse wave form outputted from a pair of electrodes arranged on a seat surface or in its vicinity. SOLUTION: A rectangular pulse a preset frequency is applied from a rectangular wave oscillator 1 to a capacitor 2 composed of a pair of insulated electrodes 2a, 2b buried near the seat surface or sewed in a surface cloth. When no crew sits on a seat, its static electric capacity is decided by a distance between a pair of insulated electrodes 2a, 2b and the dielectric constant of the material and owing to sitting of a crew, the dielectric constant near the pair of insulated electrodes 2a, 2b changes to its large side, and floating capacitor 2' caused by a man is generated. A voltage value of a supply signal from a noise filter 4 for extracting a signal component from the output of a differential amplifier 3 is compared with the reference voltage value in a judging circuit 5 and it is judged whether any crew is sitting on a seat or not and the result thereof is outputted.</p> |
