| 摘要 |
A reflex proximity sensor includes a light emitting source which directs a beam by way of a beamsplitter toward a retroreflective surface, which reflects incident light back towards the source. A non-uniform (eccentric) convex lens is positioned in the beam path to produce a beam of light which is dispersed along a sensing axis, so that an eccentric cross-section beam is directed toward the retroreflective surface. The portion of the beam which reflects off the retroreflective surface passes back through the non-uniform convex lens and reflects off of the beamsplitter, and is directed to a photodetector. As an object traverses the beam in the direction of the sensing axis, the leading (or trailing) edge establishes a change in intensity level of the beam portion that reaches the detector. The output of the detector provides a signal representative of the edge position of the object.
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