Abstract

A new ultra-precision profiler has been developed in order to measure such as asymmetric and aspheric profiles. In the present study, the normal vectors at each points on the surface are determined by the reflected light beam goes back exactly on the same path as the incident beam. The surface gradients at each point are calculated from the normal vector and the surface profile is obtained by integrating the gradient. The measuring instrument was designed according to the above principle of the measuring method. In the design, four ultra-precision goniometers were applied to the adjustment of the light axis for the normal vector measurement. In the measuring instrument, the angle-positioning resolution and accuracy of each goniometer are respectively 1.8x10-8rad and 2x10-7rad. The present measuring method is necessary to have the coordinate accuracy of sub-micron for the normal vector measurement points. In the previous meeting, we have presented that normal vector measured points with sub-micron accuracy can be determined by the self-calibration method. In this paper, the self calibration method has been evaluating to have capability to the surface profile measuring accuracy with nanometer order using a concave mirror is discussed.