非球面干涉儀之離軸對心校正

The off-axis alignment of an asphere by a Fizeau interferometer

陳彥安(Yan-an Chen)

指導教授 ： 梁肇文

國立中央大學/理學院/光電科學研究所/碩士(2011年)

摘要

在非球面檢測的技術中，泛用型非球面檢測干涉術(Geometrical null interferometry)是發展主流技術之一，我們利用了幾何消除像差(Geometrical Nulling)概念，發展彈性四軸消除像差干涉儀(Flexible 4 axis geometrical null optical interferometer)，此干涉儀利用四軸運動機構沿著光軸進行旋轉方式掃描整個待測鏡面，完成量測。而整個彈性四軸消除像差干涉儀系統三個軸心之間的離軸對心校正問題，是此干涉儀系統所需要設計的關鍵技術，而這個關鍵技術的目標，必須使干涉儀系統在進行樣品旋轉量測時，所擷取到的干涉條紋皆可以解析，使其相位移干涉術演算法可以成功演算。
本論文的目的是藉由分析多個菲佐干涉儀的離軸干涉圖形來建立一個對準非球面鏡片與旋轉平台的機械軸的方法，並利用Zernike多項式的係數變化演算來作計算，這個方法可以檢測出對心誤差的向量方向與大小，在反覆疊代過程中，將錯位的非球面鏡片校正回對準軸心的狀態，我們在模擬實驗結果裡成功展現了此方法的精確性。

關鍵字

非球面干涉儀 ； 對心校正

並列摘要

In the research fields of the asphere testing, geometrical null interferometry is currently the major trend. We designed the flexible four axis geometrical null optical interferometer . The system use the concept of Geometrical Nulling. The interferometer use four axis to rotate and scann along the optical axis of the asphere. The alignment problem of the three major axis in the flexible four axis geometrical null optical interferometer is the key technique to the successful measurement. The goal of the alignment procedure is to have the interferogram be resolved during rotation scanning phase shifting interferometry.
This research paper aims to develop a method to align an obscured aspherical surface with respect to the mechanical axis of a precision rotational stage by analyzing the multiple off-axis interferograms measured from a phase shifting Fizeau interferometer. By utilizing the Zernike Coefficients, this proposed method can detect the vectorial direction change of mis-alignment errors by least square fitting. An iterative process is possible to be implemented to bring the misaligned aspherical surface back to aligned status. The accuracy of the alignment method is successfully shown in the simulation results

並列關鍵字

alignment ； geometrical null interferometry

參考文獻

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[7]. H. S. Chang, C. W. Liang, C. C. Lee,” Flexible null interferometry of the aspherical surface” SPIE Optics+Photonics, 8126-14, 2011