本文旨在研究利用繞射光學方式結合位置感測器(PSD)來量測物體變形量之方法。將反射式薄膜光柵緊貼於待測物體上，當雷射光源照射於光柵上時，會因為繞射現象而產生繞射光，本文主要擷取+1號及-1號繞射光在PSD上的信號來進行變形量測。根據繞射原理，光柵的條紋密度會決定繞射光之角度，當待測物產生變形量時光柵條紋密度也會隨之改變，並使PSD上的兩個繞射光點產生位移量，故光柵條紋密度的變化可由PSD精準感測光點之位移來測出，並藉此可量測待測物之變形量。
本文採用雙PSD的設計，一方面可提高系統的信號輸出，另一方面也可消除剛體旋轉而產生的誤差。本文利用反射式光柵、PSD、雷射光源、運算放大電路等元件，自行開發出變形量測器，並以拉伸試驗進行校驗分析，證明此量測器之可行性。

The subject of this thesis is to modify a deformation measurement device based on diffractive optics. A reflective grating film was bonded on the specimen. When a laser beam strikes the reflective grating, several diffraction rays can be observed. Two position sensitive detector (PSD) where employed to track the diffraction rays order +1 and order-1. The grating film on the specimen is deformed accordingly when the specimen is deformed, so that the frequency of the grating and the diffraction rays are altered. Therefore, we can measure the frequency change of grating and the deformation of specimen through the light point displacement on PSD sensor.
This research uses dual PSD for not only strengthening the intensity of output signal but also eliminating the error of rigid body rotation.
In this research we develop a deformation measurement system which consists of a reflective grating film, dual PSD, a laser diode, and a PSD signal processing circuit, etc. This deformation measurement system proved workable through a tension test procedure, and the result shown a good linear output.

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