Power Scavenging Microsystem for Smart Contact Lenses.

Area of Science:

• Biomedical Engineering
• Materials Science
• Energy Harvesting

Background:

• On-the-eye microsystems, or smart contact lenses, offer advanced functionalities like vision correction and health monitoring.
• Powering these low-profile devices on the curved surface of the eye presents a significant technical challenge.
• Existing power solutions often rely on external accessories or wireless power transfer, which can be inconvenient.

Purpose of the Study:

• To design and fabricate a self-sustaining, low-profile hybrid power source for ocular microsystems.
• To address the challenge of powering flexible electronics integrated onto the ocular surface.
• To develop a power solution that does not require external accessories for continuous operation.

Main Methods:

• Fabrication of a hybrid energy unit integrating a flexible silicon solar cell and a magnesium-oxygen (Mg-O2) metal-air energy harvester activated by eye blinking.
• Characterization of the power output from both the photovoltaic and the blinking-activated components under various conditions.
• Integration of a power management circuit with a supercapacitor to stabilize and boost the harvested energy for continuous power delivery.

Main Results:

• The flexible solar cell achieved power densities of 42.4 µW/cm² (indoor) and 2.5 mW/cm² (outdoor).
• The eye-blinking Mg-air harvester demonstrated a maximum power density of 1.3 mW/cm².
• The integrated power management system successfully delivered a continuous ≈150 µW at 3.3 V DC.

Conclusions:

• A novel hybrid power system capable of continuously generating electrical power for smart ocular devices has been successfully developed.
• This power pack offers a self-sufficient and integrated solution, eliminating the need for external power accessories.
• The developed technology paves the way for advanced, untethered on-the-eye microsystems for diverse applications.