| 摘要 |
<p>PURPOSE:To sense a trespasser which trespasses at a specific speed at a short distance, an intermediate distance, and a long distance over a wide range by arranging at least three sense electrodes asymmetrically. CONSTITUTION:The arrangement of the right and left sense electrodes is so set that the distances d3 and d4 between the centers are asymmetrical about the center sense electrode E2. Consequently, even when the output signals 21, 22, and 23 of the sense electrodes E1, E2, and E3 are superposed one over another at the short distance, the gap d3 between the electrodes E1 and E2 is sufficiently large, so a 1.5Hz wave shape shown by a curve (f) is obtained. At the intermediate distance, the wave shape is distorted slightly, but this is not a problem. At the long distance, a >=1.5Hz wave shape like a curve (h) can be obtained with two signals obtained from the electrodes E2 and E3, so the asymmetrical arrangement of the electrodes becomes extremely effective. The gaps between the sense electrodes are set that, for example, d2 < d1 < d3 (d1=1, d2=0.8, and d3<1.3), but those are selected optionally according to a combination of optical systems.</p> |
