Laser scanning

To control the scanning motion, scanners need a rotary encoder and control electronics that provide, for a desired angle or phase, the suitable electric current to the motor (for a polygon mirror) or galvanometer (also called galvos).

Two-dimensional systems are essential for most applications in material processing, confocal microscopy, and medical science.

There are also microscanners, which are MEMS devices containing a small (millimeter) mirror that has controllable tilt in one or two dimensions; these are used in pico projectors.

When two optical lenses are moved or rotated against each other, a laser beam can be scanned in a way similar to mirror scanners.

By taking a distance measurement at every direction the scanner rapidly captures the surface shape of objects, buildings and landscapes.

The principle that is used for all these applications is the same: software that runs on a PC or an embedded system and that controls the complete process is connected with a scanner card.

This scanhead consists of two mirrors that are able to deflect the laser beam in one level (X- and Y-coordinate).

The third dimension is - if necessary - realized by a specific optic that is able to move the laser's focal point in the depth-direction (Z-axis).

Here the software has to control what is done exactly within such a multihead application: it is possible that all available heads have to mark the same to finish processing faster or that the heads mark one single job in parallel where every scanhead performs a part of the job in case of large working areas.

Many barcode readers, especially those with the ability to read bar codes at a distance of a few meters, use scanned laser beams.

Laser light shows typically uses two galvanometer scanners on an X-Y configuration to draw patterns or images on walls, ceilings or other surfaces including theatrical smoke and fog for entertainment or promotional purposes.