本論文提出一套以光偵測器取代CCD攝影機分析疊紋條紋的系統：「疊紋式位移量測系統」。本系統主要可分為兩部分：疊紋量測系統與相位校正系統。疊紋量測系統是基於疊紋效應與光柵自成像效應(Talbot effect)所架設的系統，以擴束雷射光準直入射兩道間隔Talbot距離的光柵，使第一道光柵自成像於第二道光柵上形成疊紋條紋。其中，光柵是以微影蝕刻的方式製作而成，具有分光的效果能夠同時讓兩個光偵測器在不同空間平面上接收疊紋光強度變化訊號，以空間移相法解析相位變化，推算光柵位移量。而校正系統則是以呂薩加圖(Lissajous pattern)的原理為基礎，用以調整光偵測器的位置與訊號修正，使兩訊號互為正交形式，令系統能正確解析相位。根據實驗結果，本系統以週期60微米的光柵搭配11倍的Talbot距離(12.51cm)作為代表，具有0.09微米的解析度與的6度/微米靈敏度，目前量測範圍受限於平台位移行程約90微米，理論上可達公分等級的量測範圍。

We proposed a new method that used the photodetector to substitute the CCD camera for analyzing the moiré pattern to measure the displacement. The measurement system is divided into two parts, the optical moiré section and phase calibration section. In the optical moiré section, we used the expanded collimated He-Ne laser beam as our light source. Afterwards, the laser beam passed through two linear amplitude gratings, which is placed with a specific distance called Talbot distance. When laser beam passed through the first grating, it will create a self-image on the second grating. Therefore, we can obtain the moiré pattern from the second grating and first grating's image. Furthermore we used the photolithography technique to make the grating split the moiré pattern into two images. The intensity of two moiré images can be detected by photodetector on two different planes. Since the intensity of moiré pattern which change along with the movement of grating. In the phase calibration section is based on Lissajous pattern theory, which is used to adjust the position of two photodetectors and calibrate the bias of signal. Used the phase calibration system to make two signals to be orthogonal, then the phase change of moiré pattern can be analyzed, and the displacement of grating can be determined. The experimental results showed that the measurement range of our system can achieve 90um. Considering the high-frequency noise, the measurement resolution of the system is about 0.09um.

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