Research on laser spot location accuracy of low-power laser diode source applied to high precision laser measurement system

Abstract

The results of laser spot location have an important influence on the accuracy of a laser measurement system. Laser diode (LD) sources have been widely used in recent years because of its low cost and easy integration. Based on the low-power LD source, a conventional laser spot location system was built to study the factors that affect the accuracy of location. We analyzed the influencing factors on laser spot location from two aspects of LD driven and charge coupled device (CCD) imaging, and experiments were conducted to further obtain quantitative analysis results and laws on different influencing factors, including the LD temperature, LD injection current, the size of imaging laser spot and its intensity fluctuation. The drifting RMS and the dithering range R were adapted to evaluate the drift and dither of the laser spot respectively, and the influence laws of location error were discussed. Finally, laser triangulation displacement sensor was taken as an optimization design example when considering the influencing factors studied in this paper. As a result, the RMS accuracy of the design example was 3.6 μm and its repeatability was 2.17 μm. The experimental results provided guidance for the optimization design of laser spot location measurement system.