Concave/convex switchable lens using active phase-change material Ge3Sb2Te6

TL;DR

This paper introduces switchable lenses using phase-change materials that can dynamically switch between convex and concave functions, enabling adjustable focus for AR and VR applications.

Contribution

The work demonstrates a novel approach to create lenses that can switch between convex and concave states using phase-change materials, a significant advancement over fixed-focus lenses.

Findings

Lenses can switch between positive and negative focal lengths.

Lenses can perform both convex and concave functions simultaneously.

Applicable to various lens geometries like cylindrical and spherical.

Abstract

Normally, the focal length of a conventional lens is fixed. Scientists have made much effort in modulating it into bifocal, which is very important for virtual reality (VR) and argument reality (AR) 3D display. It is even much more difficult for a lens to realize both convex and concave functions with one geometric structure, that is, a concave/convex switchable lens, which can tune 3D real-images and virtual-images in AR and VR, corresponding to long depth of view in 3D display. Based on the tunable refractive indexes of phase-change materials, here we propose a series of concave/convex switchable lenses. When the phase-change material is in different states, one switchable lens is able to perform a negative or positive focal length, or perform negative and positive focal lengths simultaneously. The lenses can be either cylindrical, spherical or other types. For the superior characteristics, these switchable lenses can be employed in various optical fields.