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Measurement apparatus and method that measure shape of surface while canceling cyclical errors to zero by summing of cyclic errors having different phases
Measurement apparatus and method that measure shape of surface while canceling cyclical errors to zero by summing of cyclic errors having different phases
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机译:在通过将具有不同相位的周期性误差求和而将周期性误差消除为零的同时测量表面形状的测量装置和方法
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摘要
The present invention provides a measurement apparatus for measuring a shape of a test surface, comprising an optical system configured to irradiate a measurement point on the test surface and a reference surface with light, and cause test light and reference light reflected to interfere with each other, a detector configured to detect an optical path length difference between the test light and the reference light by using interfering light and a processor configured to determine a position of the measurement point based on a plurality of detection results by the detector, wherein a detection result includes an error which cyclically changes, and the plurality of detection results include n detection results obtained in n states in which optical path lengths of the test light are different from each other by 1/n (n≥2) of a cycle of the error.
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