視覺輻輳調節衝突(Vergence–accommodation conflict, VAC)為擴增實境頭戴式顯示器(Augmented reality head mounted displays, ARHMDs)常見的問題，其主要歸因於頭戴式顯示器的影像資訊在固定的成像平面。本研究論文利用實驗室先前所研製的共軸雙焦距液晶透鏡，並結合線性偏振轉換的液晶元件操作於擴增實境的光路中，研究其景深調制的效果。
　　研究先以液態透鏡操作於ARHMDs光路中，並操作其屈光度調制對應的成像平面位置量測與理論值計算比較其一致性。接著，改以共軸雙焦距液晶透鏡進行實驗研究，該液晶透鏡使用較低雙折射係數的液晶材料以降低色像差問題，並藉由施加兩個不同的電壓操作使液晶透鏡具有最小的波前誤差其數值約為0.25 λrms。最後，將最佳化的液晶透鏡應用於ARHMDs光路中，並以其雙焦距模式操作配合一電操控之90度扭轉角液晶盒，並以一屈光度對應一圖像，圖像切換與對應透鏡屈光度的同步，最終呈現輸入影像具有三成像平面的效果，其視覺認知感受到三個影像分別清楚存在於不同景深位置。
　　更進一步使用本實驗室所製作之雙液晶層(Two LC layers, TLCL)液晶透鏡，先以電操控之90度扭轉角液晶盒施加電壓且其頻率與影像訊號同步達到雙成像平面條件，並配合另一組電控之90度扭轉角液晶盒應用於ARHMDs中，如此設計具備較廣可調動成像平面能力可達到影像調整位置由7公分至160公分處，以及藉由兩片90度扭轉角液晶盒之四種電壓開關組合，即可達到同一時間下具備四個不同深度的平面。

Vergence-accommodation conflict is a common issue in augmented reality head mounted displays (ARHMDs) because of a usual fixed image plane. In this thesis, the proposed two LC layers (TLCL) lenses with coaxial bi-focus electrically driven with two independent voltages is used and demonstrated their capabilities in ARHMDs. The optimal TLCL lens shows the minimum wavefront aberration close to 0.25 λrms. Finally, the coaxial bi-focus TLCL lenses show operational concepts of multi-focal planes to achieve better performance in ARHMDs.

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