利用超穎透鏡陣列實現像素穿插之薄型近眼顯示器

Abstract

近眼顯示器為現今顯示器技術發展之一大趨勢，其在虛擬實境或擴增實境的系統框架下提供了傳統平面顯示器所無法實現之沉浸式觀看體驗。然而，目前所開發出的近眼顯示器存在許多限制，且其龐大的體積影響了使用者的穿戴體驗。本研究首先整理並分析現有的近眼顯示器技術，並提出將微發光二極體顯示器與光束偏折式超穎透鏡陣列結合之近眼顯示器。受益於現今奈微米製程技術之發展，兩元件的結合將使該系統擁有非常薄的厚度。本研究分析並實現了此種陣列式成像系統，同時展示了以超穎透鏡進行影像接合、像素穿插與重疊之可能性。透過此種技術可有效地實現全彩顯示並大幅提高影像之像素密度。本研究透過時域有限差分法及近遠場轉換設計並模擬超穎透鏡，透過光束追跡法所優化出之相位分布將使其能正確並有效地成像並偏折光線至使用者之瞳孔中。實際應用所提出之薄型近眼顯示模組之虛擬實境系統及擴增實境系統擁有極薄的厚度，在實驗上驗證了對陣列式成像原理的理解以及各個成像方案的可行性。本研究亦基於光束追跡法模擬所提出之系統在應用不同的成像方案時，最終所投射出的虛像，並以此進行陣列成像視野分析。模擬結果與實驗結果相符，相互驗證了兩者的正確性。透過未來的改良及實現更完整的系統架構有望使其提供更完善之成像品質。

Near-eye displays (NEDs) have become a major trend in modern display technology, providing an immersive viewing experience in virtual reality (VR) and augmented reality (AR) systems that traditional flat-panel displays (FPDs) cannot achieve. However, current NEDs face many limitations, with their bulky size affecting the user's wearing experience. This research first reviews and analyzes existing NED technologies and proposes an NED that integrates a micro-light-emitting diode (micro-LED) display with a beam-deflecting metalens array. Benefiting from advancements in nanometer-scale fabrication technologies, the combination of these two components allows the system to achieve an ultra-thin form factor. This research analyzes and implements such a multi-channel imaging system, demonstrating the potential of using metalenses for image stitching, pixel interlacing, and pixel overlapping. These imaging schemes effectively achieve full-color displays and significantly enhance image pixel density. The metalens was designed and simulated using the finite-difference time-domain (FDTD) method and near-field to far-field transformation, and the optimized phase distribution through ray tracing enables it to accurately and efficiently form images and deflect light into the user's pupils. When realized experimentally in VR and AR systems, the proposed thin NED module indeed features an excellent form factor, and experimental validation confirms the understanding of multi-channel imaging principles and the feasibility of various imaging schemes. Additionally, based on ray tracing simulations, this research analyzes the field of view (FoV) for multi-channel imaging by simulating the virtual image projected by the system under different imaging schemes. The consistency between simulation and experimental results mutually validates their accuracy. With further improvements and the realization of a more complete system architecture, this technology is expected to provide enhanced image quality.