Laser scanner

In modern engineering, the term laser scanning is used with two related, but separate meanings. The first, more general, meaning is the controlled deflection of laser beams, visible or invisible. Scanned laser beams are used in some 3-D printers, in rapid prototyping, in machines for material processing, in laser engraving machines, in ophtalmological laser systems for the treatment of presbyopia, in confocal microscopy, in laser printers, in laser shows, in Laser TV, in ceramic laser treatments, and in barcode scanners.

The second, more specific, meaning is the controlled steering of laser beams followed by a distance measurement at every pointing direction. This method, often called 3D object scanning, 3D laser scanning or lidar, is used to rapidly capture shapes of objects, buildings and landscapes. A laser rangefinder is a device which uses a laser beam to determine the distance to an object.

This article focuses on the general meaning, i.e., on the methods and applications of scanned laser beams.

Most laser scanners use moveable mirrors to steer the laser beam. The steering of the beam can be one-dimensional, as inside a laser printer, or two-dimensional, as in a laser show system.

Additionally, the mirrors can lead to a periodic motion - like the rotating mirror polygons in a barcode scanner or so-called resonant galvanometer scanners - or to a freely addressable motion, as in servo-controlled galvanometer scanners. One also uses the terms raster scanning and vector scanning to distinguish the two situations.

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