High-end laser measurement, no longer a luxury
03 October 2018
Just like most pieces of sophisticated electronic kit, laser measurement sensors, when first introduced, were costly and somewhat limited in their capabilities. On-going product development, coupled with improved manufacturing processes, has largely overcome these early restraints facilitating accurate laser measurement in both high- and low-end applications.
Why choose a laser based sensor?
Modern Photoelectric sensors typically employ one of two light technologies, either LED or laser and the choice of light source can be as important for a reliable application as the choice of sensing mode, i.e. opposed, retro-reflective or diffuse.
For practical purposes the main differences between laser light and LED light is how it reacts with the outside world. For the ‘techies’ the key property is coherence. Both laser and LED use a diode to generate the light, the laser then bounces this light back and forth within its housing to generate more of the same wavelength of light (monochromatic, single colour), and more critically all the waves are in line with each other (coherent). LEDs also generate near monochromatic light. They have a broader spectrum of wavelengths than lasers but the critical feature is that the light is incoherent, the wavelengths are randomly produced.
All natural light and most man-made light is incoherent and has many wavelengths which is why it spreads out from its point source as it travels, whereas laser light remains in a tightly focused beam over great distances.
Read the full article in the October issue of DPA
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