An electrochromic alarm system for smart contact lenses

Abstract Wearable devices are becoming essential tools for mandatory daily health checks. The technology permits the sounding of alarms in response to critical conditions and as part of a continuous, real-time smart healthcare system. Among wearable devices, the smart contact lens is a pivotal technology, as it permits vital-sign monitoring through lachrymation and an augmented visual reality that can be used for the provision of information. Past research regarding smart contact lenses has relied on wireless communication for data transmission, which has necessitated the use of additional receivers. Furthermore, no research has thus far been published that deals with the provision of information through image visualization on the contact lens. Here, we describe an electrochromic alarm system that operates via electrochemical reactions with ions in tears and achieves data transmission and the provision of information. The system was shown to function in harsh conditions and with limited space and thickness. It was able to maintain contact with tears as a result of its curved shape. The voltage and duration of the potential applied to our electrochromic system were controlled in a way that achieved a broad range of color changes and frequencies. Furthermore, diverse patterns were demonstrated by controlling the duration of the applied voltage, and words were visualized via telecommunication with Morse code. We believe that the electrochromic alarm system reported here is able to be integrated into smart contact lens while extending the possibilities of data transmission and information provision for the users.