本論文提出一套奈米級面內位移量測技術－「波長調制外差散斑干涉儀」。 利用雷射二極體波長可調制的特性，以鋸齒波之電流調制，使其波長產生週期性的變化，再結合巧妙的光路設計，利用刻意製造的光程差，干涉後即產生外差光源，並利用此外差光作為主要的量測光源。 外差干涉術主要是將待測訊息載入光相位之中，擷取光相位以換算待測資訊。本論文以散斑干涉術、都卜勒移頻與光柵干涉術的理論基礎，設計出面內位移量測裝置。理論推導顯示，面內位移資訊確實能夠經由本實驗架構的設計載入干涉光之相位中。本研究開發出新的相位演算法，程式化後可以取代鎖相放大器，將系統成本大大降低。 根據理論推導，本系統之理論解析度為1 pm。實驗結果證實，考慮環境擾動的情況下，本系統之實際解析度約10 nm，量測靈敏度為0.802 °/nm，系統最大可量測速度為18 μm/sec。 本文中也對量測誤差進行討論，包含系統誤差與環境誤差。本研究架構對於環境誤差尚有改進之處，未來也將對於系統的缺失進行改善。 本系統利用光學量測的方式，可以精密地量測位移量，搭配價格低廉的架構與新的演算法，可取代昂貴的儀器設備，於精密定位系統的發展上，將是一套有發展潛力的精密量測技術。 A wavelength-modulated heterodyne speckle interferometry for measurement of in-plane displacement is proposed. The heterodyne light source was made through direct modulation of a diode laser wavelength. The in-plane motion could be measured by means of using continuous wave illumination in a length imbalanced heterodyne speckle interferometer. We developed a new phase-extraction-algorithm to calculate the optical phase variation which results from the in-plane movement. The object displacement would be determined from the measured phase variation and by the speckle interferometry theorem. The theoretical predication shows that the resolution is about 1 pm and the sensitivity is 0.801 °/nm. From the experimental results, the range of measurement system is up to 10 μm. The maximum velocity measuring ability is 18 μm/s, and the system resolution is about 10 nm. We also discussed the measurement errors in the study, such as system error and random error.
