Optolectronic light barrier for security applications has frame with pairs of lamps separated by pairs of light sensors and has opposed frame with 45 degree mirrors set in two staggered rows

摘要

The light barrier for detecting an obtrusive object has a frame (1) with pairs of lamps (S1-S4) with pairs of light sensors (E1-E4) beneath them. A frame (2) on the other side of the opening has two rows of mirrors (10-17) angled at 45 degrees. The frame has a row of openings through which light may reach the mirrors and be reflected to the sensors. A slightly diverging light beam (alpha) from the top lamp is reflected from the top mirror and the second mirror in the front row to form a return beam (beta) falling on the top light detector.