本研究開發一種「雙光束偏振干涉術應用於滾轉角位移量測」技術，應用於一精密Roll(滾轉)角位移量測系統。該系統有效改善目前Roll角位移量測技術所面臨之問題：量測範圍受限與受入射角偏移干擾。本技術使用雙折射晶體作為量測元件，透過偏振相機結合偏振干涉術，可快速獲取雙折射晶體姿態角變化引入的相位差，並且利用Roll角位移與相位差變化之線性關係，計算出Roll角位移量。 本技術另外藉由特殊設計之雙光束系統架構以達成準確量測。雙折射晶體Pitch角位移時同樣會引入相位差，造成Roll角位移量測不準確。而系統利用雙折射晶體Pitch角位移時兩道光入射角變化相反，導致相位差變化相反之特性，將相位差變化平均運算以消除Pitch角位移引入的相位差。此架構使得本系統可以大幅消除Pitch角位移對於Roll角位移量測系統的干擾，達到高準確性Roll角位移精密量測之目的。 本研究使用雙折射晶體姿態角位移時之相位差變化，達成高準確性Roll角位移之精密量測。在多種量測實驗中，不同變化方式之Pitch角位移干擾皆可被有效消除，並由重複性實驗驗證系統之穩定性與量測線性度。本研究利用實驗以分析系統之量測範圍與解析度，也分析系統架構中可能出現的系統誤差與解決辦法。實驗結果表明，本系統可於Pitch角位移2°之內實現Roll角位移的精密量測，量測範圍可達10°且系統解析度可達 0.38 arcsec。;This research develops a technique of “Dual Beam Polarization Interferometry for Roll Angular Displacement Measurement”, which is applied to a high stability roll angular displacement measurement system. The system effectively improves the current problems of roll angular displacement measurement technology which are the limited measuring range and the interference of the incident angular displacement. This technique uses birefringent crystal as measuring element, when a beam of light passes through the birefringent crystal, phase difference variation will occur when there’s an attitude angular displacement of the crystal. Based on this phenomenon, the proposed technique uses phase detection of polarization interferometry with a quarter wave plate and polarization camera, the roll angular displacement of the birefringent crystal can be determined by the detection of phase difference variation. In addition, the technique achieves high stability roll angular displacement measurement through a specially designed dual beam configuration. The phase difference will also be introduced when there’s a pitch angular displacement of the birefringent crystal. This phenomenon will cause the roll angular displacement measurement to be inaccurate. When the pitch angle of the birefringent crystal is changed, the incident angles of the two lights change in opposite directions. The system utilizes this characteristic, averages the opposite phase difference introduced by pitch to eliminate the phase difference interference. This configuration enables the system to greatly eliminate the interference of pitch angular displacement to the roll angular displacement measurement system, and achieve the purpose of precise measurement of high stability roll angular displacement measurement. The system utilizes the phase difference change introduced by the attitude angular displacement of the birefringent crystal to achieve the precise measurement of the highly stable Roll angular displacement. In a variety of measurement experiments, the pitch angular displacement interference of different patterns can be effectively eliminated, and the stability and measurement linearity of the system are verified by repeated experiments. This study uses experiments to analyze the measurement range and resolution of the system, and also analyzes the possible systematic errors and solutions in the system configuration. The experimental results show that the system can realize the precise measurement of the Roll angular displacement within the interference of the pitch angular displacement of 2°. The measuring range can reach up to 10° and the system resolution is 0.38 arcsec.
