習用雷射光學尺架構都是非共路徑架構，參考光與待測光行進的路徑不相同，量測誤差長達數百奈米，限制了其在精密機械或精密製照上之應用，其量測解析度與準確度受到極大限制，環境擾動問題實乃雷射光學尺技術瓶頸。 本文中提出了一種共路徑雷射光學尺(Common-path Laser Encoder)，在本文中簡稱CPLE，它具備架構簡單、高抗環境擾動能力、與高量測解析度等優點。CPLE採用兩個狹縫的相位偏移技術(two-slit phase shifting)，可從干涉後的一道光路提取相位差90度的兩個正交訊號，該相移技術減少光學元件數目，降 低光學元件所引進之誤差，因此CPLE 安裝簡單，具工業應用優勢。 本研究將CPLE在長行程與短行程位移進行量測性能實驗評估，並對CPLE進行 誤差分析。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15.7 ± 4.1 nm，解析度約1.2 ± 0.52 nm。故CPLE在奈米定位中是一個優越 的位移感測裝置，在超精密機械應用極具潛力。 Commonly used laser encoders are non-common-path. The non-common-path configuration between the measurement and reference beams is subject to environmental disturbances, and thus produces an additional error. Such an error is usually more than tens of nanometers. The environmental disturbance effect becomes a bottleneck for nano- or subnano-meter measurements. This study presents a common-path laser encoder (CLPE) with a simple optical configuration. Because the CPLE is common-path, it possesses high measurement resolution and immunity to environmental disturbances. The CPLE adopts a two-aperture phase-shift technique to achieve phase shift after the reference beam interferes with the test beam in the same optical path, and cause an additional phase shift of 90。 We verified the performanceof the CLPE for long-range and short-range displacement measurementsprocess. The error analysis to CPLE was also detailed. Analysis and experimental results demonstrate that the stability of the CPLE in one hour is 15.7 ± 4.1 nm, and the estimated measurement resolution is 1.2 ± 0.52 nm. The CPLE has a great potential for nanopositioning applications.
