Digitized optofluidic element and its application to tristate lens for presbyopia correction

Abstract

Current optofluidic devices are analog focus-tunable elements with a continually varying focus between foci. An innovative digitized optofluidic element was developed to enable fast switching between the foci. The operation involves an internally placed elastic membrane of changing shape between the refractive and diffractive forms with a tiny amount of fluid transfer by a micro-actuator. This allows for switching the digitized optofluidic element between the refractive and diffractive states of the preset optical powers. A multimodal relief surface design was used in the diffractive state to manage the diffractive grooves and improve the chromatic characteristics. We applied finite element analysis to establish the membrane mechanical properties. The proof-of-concept prototypes were made using material bonding fabrication processes and were used to demonstrate an elastic membrane shape change between the refractive and diffractive forms for switching between the corresponding optical states. The design of the digitized optofluidic element allowed for bistate or tristate switching by a single actuator. The switchable element can be fairly thin, enabling conversion of a fixed lens into a dynamic lens switchable between two or three foci. The application of the tristate design to eyewear for presbyopia correction is discussed. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.