Displacement and angle measurement by laser interferometer with LCD

Six degree of freedom motion errors of a linear stage of machine tool, a coordinate measuring machine, and so on is very important factor of improvement of their accuracy. In order to measure the displacement and angle, the laser interferometer is used. However the configuration of the interferometer is complicated and the target mirror is easily out of measuring range. In this paper, the measuring method, which measures the displacement and the angle using a ball lens as the retroreflector and LCD as the optical modulator, is proposed.