Eye-Tear-Driven Electret Energy Harvester for Smart Contact Lenses

We report the fabrication process flow and testing of an electrostatic electret-based energy generator that utilizes the natural blinking motion of the eyelids. The device is a variable area capacitor formed with highly doped silicon as one electrode and eye tear as the other electrode. Such a device can be used as a part of a power pack used to power wearable low-power devices. A linear actuator was used to replicate blinking motion. The 10x10 mm
²
harvester can deliver a peak power of 1.54 μW. A miniaturized version of the energy harvester was incorporated into a smart contact lens prototype.