為了提升在台灣在非球面光學鏡片上的自我檢測能力，本團隊成功開發出台灣第一套旋轉掃描式非球面干涉儀，憑藉著自行開發的振動調變式相移干涉術與全域子孔徑拼接演算法加大普通干涉儀的動態範圍，能夠完整量測大於參考鏡的數值孔徑之球面鏡，甚至是半球狀的透鏡皆可以量測。再透過位置優化技術，將子孔徑上所量測到的干涉條紋在徑向方向上的條紋密度降至最低，用以減少環形區域之數目並且增加非球面可量測的範圍，預計可以量測含有1000個波長偏離度的圓對稱非球面鏡，根據實驗結果能夠準確地量測出與非球面設計值差距0.5個波長的誤差量。 此非球面干涉儀最獨特的技術在於利用旋轉平台運轉時所帶有1 μm左右的機械振動，將原本看似不可避免的振動干擾利用振動調變式相移干涉術轉為有用的相移資訊，進而重建出子孔徑表面相位。在每一個環狀區域上皆不須停下量測，透過機械振動即可達到動態量測相位的目的，每個環形區域大約只需要2分鐘就可完成干涉條紋的量測。再透過平行運算系統，降低整體的運算時間，根據量測1吋球面鏡之結果顯示10個環形區域總共346個子孔徑大約只需要30分鐘即可以完成量測。 因著旋轉掃描的量測方式，此干涉儀有高密度量測的優點，不只能夠降低拼接誤差的變異量，而且還可以免除製造高精密度的參考鏡之成本與時間。擁有降低量測時間、購置成本與提高精準度之優勢。 ;In order to enhance the optical testing capability of aspheric lens in Taiwan, we first developed a rotational scanning aspherical surface interferometer. This subaperture stitching interferometer has more dynamic range than that of a conventional interferometer in virtue of the techniques we developed: vibration modulated phase shifting interferometry and global subaperture stitching algorithm. It can measure spherical lenses with the numerical aperture higher than that of the reference lens. Even a half sphere could also be measured. The optimized null method can minimize the tangential fringe density. This helps to reduce the number of annular regions and also increase the measureable region on the aspheric surface. This interferometer is anticipated to be capable of measuring 1000 waves surface departure of rotational symmetric asphere. According to the experimental result, we can accurately measure a departure of 0.5 waves from the asphere design. The most unique technique of this aspherical surface interferometer is to use the 1 μm vibration of the rotational stage. It transfers the inevitable vibration error to be the useful information by using vibration modulated phase shifting interferometry to reconstruct the subaperture phase. By using the vibration to achieve the dynamic measurement purpose, it only takes 2 minutes to complete the annular region measurement. Through the parallel computing system, the computational time is also reduced. According to the experiment on a 1 inch diameter spherical surface, it only takes 30 minutes to finish the measurement and that includes 346 subapertures in 10 annular regions. By the rotational scanning measurement method, this interferometer has the advantage of high overlapping density stitching capability. It not only reduces the variance of stitching error but also can avoid the manufacturing cost on high precision reference lens. It has the advantage of reduced measurement time, costs and improves accuracy.
