| Summary: | 碩士 === 龍華科技大學 === 工程技術研究所 === 97 === This paper proposes a few cheap and non-contact methods to measure the in-plane and out-of-plane displacements of a measured object using a laser. All the average errors of the different measured displacements are smaller than 10nm. About the measurement for an out-of-plane displacement (along the direction of the incident laser beam), Michelson interferometry and Fizeau interferometry are respectively modified to form concentric or elliptical interference fringes with two beams scattered or diffused from a local measured-object surface and a local reference-object surface, respectively. According to the shifting of the interference fringes, the out-of-plane displacement of the local measured-object surface can be derived. About the measurement for an in-plane displacement (vertical the direction of the incident laser beam), interferometry using two beams both scattered or diffused from a local measured-object surface are symmetrically recombined to form concentric or elliptical interference fringes. According to the shifting of the interference fringes, the in-plane displacement of the local measured-object surface can be derived.
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