Light screen security arrangement making use of the modulation of a light beam onto the reflector

摘要

The invention relates to a light protection security system designed for reliably observing an object within a certain scanning plane. The invention makes use of the addition of information to a light beam by means of interrupting (chopping) a retroreflective reflector according to a fixed pattern, with the object of detecting a change in this information by detecting the action of an object within the scanning plane. In the process, the light beam scans a certain plane, and the signal reflected and modified by the reflector is detected.