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Multi-probe system comprising three laser interferometers and one autocollimator for measuring flat bar mirror profile with nanometer accuracy on a high-precision micro-coordinate measuring machine

We described a multi-probe system comprising three laser interferometers and one autocollimator to measure a flat bar mirror profile with nanometer accuracy. The simulation and pre-experiment of multi-probe system have been conducted on an X-Y linear stage which is composed of a ball bearing slider and a stepping motor. The two standard deviation of the flat bar mirror profile is mainly fitting the range of simulation results (±20 nm). Comparison of our measured data with the results measured by ZYGO white light interferometer system showed agreement to within approximately ±30 nm, excluding some points at the edge of the mirror. From the pre-experiment results, we conclude that the systematic error caused by accuracy of the moving stage can't be ignored. To eliminate this systematic error, the multi-probe system has been implemented on a high-precision micro-coordinate measuring machine (M-CMM) that has been built at the Advanced Industrial Science and Technology (AIST).