A piecewise controllable tunable lens with large aperture for eyewear application

Abstract

Here, we present a piecewise controllable tunable lens with large aperture which is composed of a soft polymer lens, an shape memory alloy (SMA) driven iris diaphragm and an SMA driven latch. The SMA driven diaphragm expands the soft polymer lens in the radial direction, thereby varying the focal length. The soft lens has the large aperture of 35 mm in diameter and shows focal length tunability of 31.7% (175-230 mm) under current signal control. The solid characteristics of the polymer lens assure robustness against gravitational force. In addition, the locking mechanism enables the tunable lens to be piecewise controllable and provides high energy efficiency. Due to these advantages, the fabricated tunable lens module can be implemented in various eyewear applications.