Galvoohjattu

Galvoohjattu, a Finnish term meaning galvo-controlled, refers to a beam-steering system that uses galvanometer-driven mirrors to deflect a light beam. In practice, it denotes an arrangement where two small mirrors mounted on galvanometer motors steer the beam in two orthogonal axes, enabling rapid, precise scanning of a target field. The term is common in Finnish technical literature on laser scanning and related optical instrumentation.

Operation: Digital commands are translated into analog voltages that drive the two galvanometers. By adjusting the mirror tilts in X and Y, the system positions the beam at desired coordinates. Scanning patterns can be raster, vector, or custom trajectories, and speeds are governed by motor bandwidth and controller firmware. Some systems incorporate closed-loop feedback from position sensors to improve accuracy.

Design considerations: Key metrics include angular range, linearity, repeatability, settling time, and jitter. Optical design must address mirror reflectivity, aberrations, and beam quality over the scan field. Calibration maps scanner angles to Cartesian coordinates, often requiring geometric correction.

Applications: Galvo-controlled scanners are widely used in laser engraving and marking, laser cutting, and micromachining. They also appear in scientific instruments for fast optical sampling, in some projection or display systems, and in research settings where precise, fast beam steering is needed.

Limitations: Wear on moving parts, hysteresis, thermal drift, and susceptibility to vibration can affect performance. Compared with MEMS or polygon scanners, galvo systems offer high angular range and accuracy, but may be limited by mechanical life and size.