習用的繞射式雷射光學尺皆為非共路徑架構，參考光與待測光行進的路徑不相同，量測誤差達數百奈米，在一般環境下限制了在精密量測以及定位加工，並且位移量測解析度與準確度受到極大影響，環境擾動的因素使雷射光學尺技術遇到瓶頸。 本研究提出了一種微型共路徑雷射光學尺(Common-path Laser Encoder，簡稱CPLE)，它具有元件少、組裝容易、高抗環境擾動能力、高量測解析度、與高準確度等優點。CPLE透過雙狹縫的相位偏移技術(two-slit phase shifting)，可將干涉訊號調整為相位差為90°的正交訊號，該技術減少了光學元件數目，光學元件引入之誤差可大幅降低。 本研究設計出微小化CPLE讀頭的光機佈局並製作出微小化CPLE的讀頭原型。在長行程位移進行量測性能實驗與商用HP5529A干涉儀進行偏差量評估，並對於易造成實驗上的誤差進行分析。在分析與實驗結果顯示，CPLE於一小時系統穩定度量測中產生漂移量為17.7 ± 4.7 nm，解析度約1.5 ± 0.5 nm。故CPLE在奈米量測中是一個誤差量較小的位移感測裝置，在超精密機械應用具有潛力。 關鍵字: 光學尺、位移量測、共路徑、長行程、光柵誤差、微小化 Commonly used laser encoders are of non-common-path configuration. The non-common-path configuration between the measurement and reference beams is susceptible to environmental disturbances, and thus produces additional error. Such an error is usually more than tens of nanometers. Under normal circumstances, the precision measurement, positioning process, and displacement measurement resolution and accuracy is greatly affected. Environmental disturbance factors makes laser optical device technology. This study proposes a micro common-path laser encoder device called (CPLE). It has lesser components, is easy to assemble, possesses high resistance to environmental disturbance, and is capable of high-resolution measurements with high accuracy and so on. CPLE shifts phase through the double slit technique (two-slit phase shifting) and interference signals can be adjusted to a phase difference of 90°signal. This technique reduces optical elements. With this technique, the effect of optical element error can be greatly reduced. For the purpose of the study, a miniaturized CPLE was designed and developed. In the long displacement performance test with HP5529A interferometer for offset evaluation, it is displayed in the analysis and the experimental results. The time dependent drift of CPLE was measured for a period of one hour and was found to be 17.7 ± 4.7 nm with 1.5 ± 0.5 nm resolution. It is therefore shown that the measurement error in nanometers for displacement sensing is small. This technique finds varied applications in ultra-precision mechanics and has enormous potential for future development.