Abstract
The authors have proposed a three-axis surface encoder, which can measure XYZ-directional displacements simultaneously by analyzing interference signals of the XY-directional ±1st order diffracted beams from two XY gratings. The proposed sensor utilizes the XY grating as a scale for the XYZ-directional displacement measurement. Therefore, the XY-directional measurement range is determined by the scale XY grating size. In this report, we present a method for expanding the XY-directional measurement range of the three-axis surface encoder by a mosaic scale XY grating. An optical sensor head for the mosaic scale XY grating was developed and basic experiments were carried out to confirm the effectiveness of the presented method.
