Holographic Waveguide Display With Large Field of View and High Light Efficiency Based on Polarized Volume Holographic Grating

Yuchen Gu,Ran Wei,Yuning Zhang,Chuang Wang,Zhongwen Shen,Lixuan Zhang,Yishi Weng

doi:10.1109/jphot.2021.3127547

Abstract

We propose a polarization multiplexing structure based on multilayer reflective polarized volume holographic gratings(PVGs) to improve the field of view and brightness of the augmented reality waveguide display. The multilayer structure forms the splicing of different response bandwidths by stacking PVGs with different periodic components, and realizes the expansion of the wavelength (angle) bandwidth. The polarization multiplexing structure controls the polarization of the diffracted light by controlling the rotation direction of the liquid crystal pitch in the liquid crystal material, so that both left-hand and right-hand circularly polarized light are diffracted to enhance efficiency. Based on these two structures, the wavelength bandwidth of PVG is increased by 40 nm, the angular bandwidth is increased by 10° and the diffraction efficiency is nearly doubled. In order to verify the feasibility of these two structures, we use the holographic waveguide display with OLED as the image source. The demonstrated waveguide prototype shows a complete display with a diagonal field of view of 55°. The brightness of virtual image was measured as high as 1100 cd/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with a transparency of 72% for ambient light.

Highlights

With the development of new technologies such as 5G communications, big data, cloud computing and artificial intelligence, the application scenarios of visual displays have become more diversified, and the form of displays is constantly innovating
As the most critical and scarce core component of the AR display system, the optical combiner influences the field of view (FOV), optical efficiency, exit pupil size and other parameters, which affect the performance of the entire display system
The structure of LCOM-polarized volume holographic grating (PVG) is proposed to increase the bandwidth of PVG, and the polarization multiplexing structure based on PVG is proposed to enhance the optical efficiency, and the feasibility is verified through experimental preparation

Summary

Introduction

With the development of new technologies such as 5G communications, big data, cloud computing and artificial intelligence, the application scenarios of visual displays have become more diversified, and the form of displays is constantly innovating. As the most critical and scarce core component of the AR display system, the optical combiner influences the field of view (FOV), optical efficiency, exit pupil size and other parameters, which affect the performance of the entire display system. The more mainstream technical solutions include beam splitting prism [3], free-form surface [4], Maxwellian display [5][6] and optical waveguide [7]. The optical waveguide can obtain a larger eye movement range while keeping its volume and weight as small as possible, which is considered to be the most promising technical solution

Methods

Results

Conclusion