Measuring system for micro radius of curvature

We have developed a system for measuring the radius of curvature of a micro spherical surface whose radius is several 10 μm to several 100 μm. This measuring system can measure a spherical surface by two methods, namely a Linnik micro-interferometer and a micro-colimator. In additon, this measuring system can measure a flat surface by a double-beam interferometer. Furthermore, the change of the optical system among those three measuring methods can be easily done by moving only the lens and shutter. Therefore, in this measuring system, each of the three measuring functions can be utilized without changing the setting of the workpiece. Thereby, the setting eror among the three measuring methods can be eliminated, so that the measuring accuracy and the measuring reliability have been improved.