| 摘要 |
<p>PURPOSE:To enable stable detection of an object by using the same light source on the light projection side of a plurality of fiber sensors. CONSTITUTION:In the case when three fiber sensors are employed, for instance, the sensors form a reflection-type sensor and are directed to an object 7 of detection. A light emitted from one light source unit 4 is condensed by a lens, passed through projection-side fibers 2 and emitted from sensor ends and it strikes on the object 7 of detection. A reflected light from the object 7 of detection passes through reception-side fibers 1 and enters sensor amplifier units 3 and a signal showing the presence or absence of the objected is outputted therefrom. By unifying the light source on the projection side, in this case, a pulse modulation frequency can be made quite the same, a reference voltage is so adjusted that a comparator 14 does not turn ON even when reflected lights from the background on the other side are superposed, and thus stable detection of the object can be conducted.</p> |
