POLARIZATION OPTICS DESIGN FOR A LASER TRACKING TRIANGULATION INSTRUMENT BASED ON DUAL-AXIS SCANNING AND A RETROREFLECTIVE TARGET

The design of the polarizing optics of an instrument that uses laser t racking triangulation for the dynamic measurement of the 3-D co-ordina tes of a retroreflective target is presented. The system, which uses d ual-axis scanning mirrors, has applications in the performance testing and calibration of industrial robots. Analytical and experimental res ults are provided for the design of the polarizing scheme to maximize beam-energy usage for a given safety classification while minimizing a ny unwanted laser feedback and secondary beams that can affect measure ment precision. Finally, a study of the depolarizing effects of air-pa th retroreflectors shows how severe degradation of measurement accurac y can result from their use in this context, which thus supports the a lternative use of a cat's-eye type target.