Optical reader for supermarket goods coding label - utilises laser beam source reflected onto coding disc on article and received by photomultipliers

摘要

An optical scanning system is used to read binary coded information from articles in supermarkets relating to price and type. Articles (16) are transported on conveyor belts (20,22) past a reading station (15). Each article has a coding disc (36) on the underside consisting of a concentric circle pattern. The fixed reading station palte (15) has an aperture (18), approximately 6mm x 15cm, through which monochromatic red light is directed. Typically, a helium-neon laser (26) provide a light source transmitted through a fibre optic bundle onto a rotating reflector (24) light reflected from the coding disc is filtered and transmitted to photo-multiplier tubes. The coded signals are amplified and transmitted to a console (45).