Light Pipe Holographic Display: Bandwidth-preserved Kaleidoscopic Guiding for AR Glasses

TL;DR

This paper introduces a holographic AR display using a light pipe with kaleidoscopic guiding, enabling a lightweight, glasses-type design that preserves bandwidth and delivers high-quality 3D images.

Contribution

It proposes a novel light pipe holographic display that decouples the light engine from the image combiner, improving AR device compactness and image quality.

Findings

High-quality 3D holographic images achieved

Effective compensation for light pipe misalignment demonstrated

Device design results in a lightweight, glasses-type AR display

Abstract

In this paper, we present a holographic display using a light pipe for augmented reality, and the hologram rendering method via bandwidth-preserved kaleidoscopic guiding method. Conventional augmented reality displays typically share optical architectures where the light engine and image combiner are adjacent. Minimizing the size of both components is highly challenging, and most commercial and research prototypes of augmented reality displays are bulky, front-heavy and sight-obstructing. Here, we propose the use of light pipe to decouple and spatially reposition the light engine from the image combiner, enabling a pragmatic glasses-type design. Through total internal reflection, light pipes have an advantage in guiding the full angular bandwidth regardless of its length. By modeling such kaleidoscopic guiding of the wavefront inside the light pipe and applying it to holographic image generation, we successfully separate the light engine from the image combiner, making the front of the device clear and lightweight. We experimentally validate that the proposed light pipe system delivers virtual images with high-quality and 3D depth cues. We further present a method to simulate and compensate for light pipe misalignment, enhancing the robustness and practicality of the proposed system.