微機電與奈米系統多功光學顯微量測儀之研製(3/3)

在奈米科技蓬勃發展的今日，科技產業無不大舉投入微小尺寸產品的研究，就 早先的科技而言，微小的振動或是物體表面的起伏與粗糙可能對於系統不會有嚴重 的影響，因為系統所要求的精度或準度遠大於此微小變動。但就現今而言，此微小 的變化均可能影響整個系統的成敗，而高精密的檢測技術正是推動這些微小化產品 的基礎科技，因此建構一套具顯微檢測能力的動態檢測設備實屬迫切需要。本計劃 以設計開發出一套具有奈米精度的光學振動量測系統為目標，藉由創新的光路設計 與全球首創之演算法，成功地將光學動態檢測技術引入到光學顯微系統之中。 本計劃中以高速CCD 開發出一套具有暫態全域變形檢測的電子斑點干涉(ESPI) 系統，藉由極短的曝光時間與精準的時序控制成功地得到一系列的暫態資訊。在電 子斑點資訊處理上，藉由影像與信號技術的一系列創新開發，本研究完成了包含利 用相關係數結合五一相移法計算出相位主幅角、以中位數濾波器進行濾波、並以路 徑獨立之演算法完成相位重建工作，最後以曲面擬合之技術得到完整變形輪廓之成 果。此外本研究還提出如何整合前人所提出的圓偏光組態干涉架構與正交訊號解相 位技術，進而將雷射都卜勒干涉術成功的整合於系統中，因此乃能達到多功能檢測 目標。在演算法方面，本文提出創新的時進相移技術，解決電子斑點干涉術在顯微 系統之中因放大倍率較大而易失去相關性的問題，其中時進正交相移技術的提出， 更可以省去系統中的相移裝置，徹底改善因調制相位不精準所造成的量測誤差。易 言之，本研究包含以光電架構、信號處理、創新光機架構來完成建構出一套全球首 創之奈米檢測系統。 在實驗成果方面，本計劃在光學設計軟體的模擬輔助下，設計出最佳的光路架 構，並建立完整的實驗流程控制系統和訊號/影像分析介面，最後進行了一連串的壓 電振動量測實驗，成功驗證了本論文所建構完成之創新架構的性能與所提出之演算 法的可行性與精確性。With the rapid advancement of nanotechnology, many industries have focused their research efforts to products of miniature size. It is to be noted that high-precision metrology is the driving force that propels miniature product forward. To further advance this line of research, there is an imminent need to develop a metrology system that can perform dynamic measurement through a microscopic system. In other words, the goal of this research is to develop an optical metrology system that can measure full-field and dynamic nanometer vibrations. By integrating an innovative optical configuration and a newly developed signal algorithm, the above-mentioned goals were completed successfully during the course of this research. In this dissertation, electronic speckle pattern interferometry (ESPI) with high speed CCD camera was adopted to achieve full-filed deformation measurement. By means of short exposure time and precise time control, a series of transient information could be obtained. Image processes including (5,1) phase shifting technology, direct correlation method, noise reduction median filter, and path-independent phase unwrapping method were all integrated to reconstruct surface profile of specimen. Moreover, based on circular polarization interferometer and quadrature signal phase decoded method, laser Doppler interferometry was combined with ESPI system successfully to pursue multi-functional optical metrology system. Besides, an innovative time-stepped phase shifting method has also been proposed. This newly developed process essentially circumvents the de-correlation problem faced by incorporating ESPI technology into microscopic system. The newly developed time-stepped quadrature phase shifting method can even remove the phase shifting device so as to thoroughly improve the accuracy. With regard to the experimental achievements, the optimal optical configuration has been constructed according to the optical simulation results. In addition, the complete experimental process control system and signal image analysis interface have also been developed. In summary, the vibration measurement results obtained from a piezoelectric plate verifies the performance of the innovative optical metrology system disclosed and accuracy of the newly developed algorithm adopted