High Accuracy Profile Measurement With a New Virtual Multi-Probe Scanning System

We present a novel virtual multi-probe scanning system and a new error separation method for the exact optical profile reconstruction. The system realized the multi-probe function by a single probe that fixed on a flexible hinge stage. The flexible hinge stage has a millimeter-level travel range and driven by a voice coil motor to realize the function of the multi-probe. In this work, a high accuracy profile measurement with a high lateral resolution is realized under the errors of the straightness, zero-adjustment, and yaw. The new method can obtain multiple sets of straightness error of the guideway in one scanning measurement. This novel virtual multi-probe scanning system and its corresponding method has the following benefits: (i) using a single probe to separate straightness error without reversal, and can accurately reconstruct the profile, (ii) the reconstructed profile has a very high lateral resolution, depending on the lateral resolution (μm level) of the probe, (iii) the cumulative amplification effect of zero-adjustment error can be eliminated by our method, (iv) the new method can obtain multiple sets of straightness error with higher reliability and accuracy compared with only one set. These benefits are proved by theoretical derivation and simulation. Experiments also prove that the new method can reconstruct the profile with high accuracy and lateral resolution.