The LX series sensing Light Screen that are simple and highly reliable means of sensing small parts or flat items which pass anywhere through the light screen. The series light screen sensing system consists of two self-contained units - an emitter and a receiver of equal size and sensing range. The emitter has multiple infrared LEDs spaced at 9.5mm (0.38") increments and the receiver has corresponding photodiodes. The emitter sequentially fires each infrared LED. Multiple photodiodes in the receiver recognize each of the emitted pulses, the result is a "cross-hatched" optical pattern. Optical synchronization enables the receiver to recognize light from each of the emitter LEDs. The optical crosshatch pattern enables the LX system to detect targets of very small diameter and extremely thin, flat objects - as thin as a piece of paper or an envelope.