Having been involved in the machine vision industry for over 40 years, it has been fascinating to follow the many iterations of laser-based displacement sensing. These changes have included an evolution as it has evolved from analog to digital operation, and from basic capabilities to today’s simple-to-use all-in-one measurement systems. Laser displacement sensors, which measure the distance from a sensor to a surface, superseded traditional displacement sensors, primarily dial indicator gages and LVDTs (linear variable displacement transducers). These traditional sensors were based on technologies that used a mechanical contact on the surface being measured. Contact measurement techniques are very effective and inexpensive for many common applications, but for in-line and high-speed applications, contact sensors have serious limitations. These include limited frequency response, potential damage to finished surfaces, errors due to deformation of soft materials, and errors from tip wear and dirt contamination.
