STREAMING INFORMATION DISPLAY

Your patient might someday be reminded of an appointment with you on a contact lens imbedded with a streaming information display. Researchers at the University of Washington and Aalto University, Finland report the completion of a proof of concept prototype that proved safe in living eyes. The prototype display consists of an antenna, a 500 × 500 µm2 silicon power harvesting and radio integrated circuit, metal interconnects, insulation layers and a 750 × 750 µm2 transparent sapphire chip containing a custom-designed micro-light emitting diode with peak emission at 475 nm, all integrated onto a contact lens. They tested the wirelessly powered contact lens display in a rabbit model. The display was tested on live, anaesthetised rabbits with no observed adverse effect. While the device could be remotely powered from as far as one metre away in the lab, wireless power could only be achieved in vivo at a distance of 2.0cm. The researchers later integrated micro-Fresnel lenses into the device to extend the display capabilities, which would theoretically allow the human eye to see the information presented on the contact lens by focusing the projected image onto the retina. Contact lenses with integrated micro-Fresnel lenses were also tested on live rabbits and showed no adverse effects.

The next step will be to develop contact lenses with multiple pixels which, in their hundreds, could be used to display short emails and text messages for the wearer. The developers envision many applications. For example, the device could overlay computer-generated visual information on to the real world to facilitate navigation, or finding the nearest Starbucks. Such a device could be linked to biosensors in the user’s body to provide up-to-date information on glucose or lactate levels. And, it could still be used to improve vision.

A R Lingley et al., Journal of Micromechanics and Microengineering, “A single-pixel wireless contact lens displayâ€, Volume 21, Number 12, doi:10.1088/0960-1317/21/12.125014.