Development of an innovative multi-detector triangulation laser probe

This study presents the design and manufacture of a prototype of a multi-detector triangulation laser probe. The developed system was configured and assembled based on the Scheimpflug principle. The probe system mainly consists of a diode laser, six collimating lenses, six position sensitive detectors (PSD), a signal processing circuit, and an A/D interface card. Through the specific arrangement of the PSD, four different measurement modules for the developed system are possible, namely the standard triangulation probe module, double triangulation probe module, pentagon-shaped triangulation probe module, and an approximately circular triangulation probe module. Bused on the calculation and filtering of the pentagon-shaped PSD signals, the measurement accuracy was improved. The developed laser probe system was integrated with a coordinate measuring machine, to construct a non-contact measurement system. According to the experimental results, the measurement uncertainty of the developed laser probe system, with respect to different surface roughness and slope, was about 15 microns. Among the four different measurement modules checked, the pentagon-shaped triangulation probe module has the best result.