Resolution-enhanced foveated integral imaging near-eye display with enlarged viewing angle using a multifocal liquid lens array

Abstract

Vergence-accommodation conflict (VAC) is a mismatch between the distance cue of a virtual image (vergence) and the focusing distance of eyes to the image (accommodation). The visual discomfort caused by VAC has been one of the main issues for near-eye display (NED) devices. Among numerous methods, an integral imaging display has been presented as the most effective solution to this by reproducing natural three-dimensional (3D) depth cues for augmented reality and virtual reality (AR/VR) NEDs. However, due to the limited optical properties of the system using a lens array, it has significant problems such as resolution degradation and narrow viewing angle. In this dissertation, a new type of foveated integral imaging near-eye display using a multifocal liquid lens array is presented to solve these problems. The resolution enhancement is realized by using the foveated integral imaging system which concentrates the field-of-view (FOV) of integral imaging 3D to a small central foveal area of the human visual system. For the viewing angle enhancement, a multifocal liquid lens array that allows an increased number of elemental images to be reconstructed as a 3D image is fabricated. Based on the various optical analysis, the optimized design of the proposed system is demonstrated for high-resolution, wide viewing angle 3D NED without compromising other optical properties. The resulted resolution and viewing angle of the proposed system are 17.13 ppd and 46°, respectively. Compared to the conventional integral imaging system, these results show 4.5 times improvement in resolution and 3.1 times improvement in viewing angle.