干渉顕微鏡観察下の粗面の垂直走査域100μmでの光路差変化の高精度測定

概要

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A vertical-scanning shape-measurement interference microscope using white light is widely used to measure 3D shape of a small object. This microscopy however cannot be used in vibrating environment. Because it is required to repeat one-way vertical movement of the predefined length and interferogram recording after that. We are researching a new technology which can accurately measure the real-time changes of optical path difference (OPD) and can trigger the recordings. When a rough surface is observed under the microscope, an interference pattern has very complex structures. To measure OPD change from the pattern, we use flexible masks to extract components of cosine change and sine change from the complex-structure change. Using the extracted changes we can obtain continuous phase change over a 100-μm vertical movement. But, the total phase change of the movement slightly depend on roughness of the measured area. This dependence is showed to be affected by a numerical aperture of an object-lens and can be reduced using a smaller aperture lens.
社団法人精密工学会の論文