Measurement of six degree bi-directional motion error of linear stage

Tokyo Denki University, School of Engineering, Senju-Asahi 5, Adachi, 120-8551 Tokyo, Japan

Abstract

We proposed the measurement system of the six degree of motion errors which is based on distance measurement by the laser interferometer. The system has six parallel laser beams and six ball lenses as the retroreflectors on the linear stage, which reflect the corresponding laser beams. In the proposed system, the error of axial direction is measured with the ordinary distance measurement method by laser interferometer. The vertical errors to the axial direction and the roll errors around the optical axis are measured by tilted beams using the wedge prism. The pitch and yaw errors in the vertical plane to the optical axis are measured by the difference between distance of two ball lenses. The former system can measure the displacement and the error angle in one-direction. The propose system are expanded and bi-directional displacement and error angle can be measured. In this paper, it is shown how to expand the measurement system. As a result, the maximum displacement errors in x, y and z directions are 242nm, 179nm and 90nm. The maximum rotational errors around x, y, z axes are 1.75 arcsec, 2.35 arcsec and 1.67 arcsec.