Development of surface gradient integrated profiler: precise coordinate determination of normal vector measured points by self-calibration method and new data analysis from normal vector to surface profile

Y. Higashi; T. Ueno; K. Eno; J. Uchikoshi; T. Kume; K. Enami

doi:10.1117/12.796070

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18 September 2008 Development of surface gradient integrated profiler: precise coordinate determination of normal vector measured points by self-calibration method and new data analysis from normal vector to surface profile

Y. Higashi, T. Ueno, K. Eno, J. Uchikoshi, T. Kume, K. Enami

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Proceedings Volume 7077, Advances in X-Ray/EUV Optics and Components III; 70770C (2008) https://doi.org/10.1117/12.796070
Event: Optical Engineering + Applications, 2008, San Diego, California, United States

Abstract

A new ultra-precision profiler has been developed to measure items such as asymmetric and aspheric profiles. In the current study, the normal vectors at each point on the surface are determined by a reflected light beam that returns along exactly 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. At a previous meeting, we reported that normal vector measured points with submicron accuracy can be determined by a self-calibration method. In this paper, the self-calibration method has been tested and shown to have the capability for surface profile measurement accuracy of nanometer order, using a concave mirror with a radius curvature of 2000 mm. The precise surface profile obtained from a measured normal vector has been studied as a new data analysis method that applies Fourier series expansion with the least-square method. Future development will include the following: the elimination of error propagation due to data analysis from normal vector to surface profile, unique determination of profile from normal vector, and enabling random measuring position of normal vector on the mirror.

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Y. Higashi, T. Ueno, K. Eno, J. Uchikoshi, T. Kume, and K. Enami "Development of surface gradient integrated profiler: precise coordinate determination of normal vector measured points by self-calibration method and new data analysis from normal vector to surface profile", Proc. SPIE 7077, Advances in X-Ray/EUV Optics and Components III, 70770C (18 September 2008); https://doi.org/10.1117/12.796070

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