Laser scanner
A precisely focused and finely bundled laser beam is used as the light source for the laser scanner’s reading system. The laser beam is deflected by a rotating polygon mirror, creating a laser beam that glides up and down. This is forwarded to the barcode carrier and then projected onto a photoreceiver as a light beam with varying degrees of reflection via a mirror and lens system. There, the optical impulses are converted into binary electrical signals. Laser scanners allow a relatively large depth of field due to the sharp beam bundling and the parallelism of the light and are able to read a low-density code at a distance of 1.5 meters. When installing laser light sources, mandatory safety measures must be observed. Today, laser scanners are not only used as stationary systems (e.g. on conveyor belts), but also in the form of mobile laser guns, which can be used to directly scan and thus identify the transported goods from the driver’s seat of a forklift truck.
For more information on designing a barcode so that it can be read by the scanner, see Designing a barcode.
Image source: © Kitch Bain – Fotolia.com