| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To reduce omission in detection to the minimum possible, when detecting an object intruding into a prescribed range. <P>SOLUTION: A pulse sensor having the first reception line and the second reception line is adopted in one transmission line. A detection distance of the first reception line is set to about 0.075m, for example. A characteristic of the minimum reception sensitivity gets thereby to a curve Seta in the first reception line. A detection distance of the second reception line is set to about 0.05m shifted by a length corresponding to a half-wavelength of an amplitude in a main frequency out of a band-limited transmission signal from the transmission line, with respect to the detection distance of the first reception line. A characteristic of the minimum reception sensitivity gets thereby to a curve Setb in the second reception line. The object existing within a distance range D2-D5 is detectable as a result thereof. The present invention is applicable for the pulse sensor. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
