Innovative 3D/2D Augmented Reality System Based on a Liquid-Crystalline Microlens Array and Full-Color Holographic Optical Element

We present a novel augmented reality (AR) display system utilizing a holographic optical element (HOE)-based approach, featuring seamless switching between three-dimensional (3D) and two-dimensional (2D) modes through a liquid-crystalline microlens array (LC-MLA). The proposed system aims to capture and present comprehensive spatial information on real-world objects. The LC-MLA is customized to suit the purpose of the proposed system, and its functionality seamlessly switches via an electrical polarizer, allowing users to effortlessly toggle between modes by simply pressing a switch button. An integrated control system automates corresponding tasks based on the selected mode. In 2D mode, the captured image is directly displayed, while in 3D mode, an elemental image array (EIA) is generated and reconstructed into a 3D image, through the LC-MLA. To ensure optimal performance for the proposed system, a custom-fabricated LC-MLA, and full-color HOE combiner have been developed. Additionally, we designed and implemented a bespoke integrated control system that synchronizes and interconnects the main devices seamlessly.