Flexible Micro-Battery for Powering Smart Contact Lens

Area of Science:

• Biomedical Engineering
• Materials Science
• Electrical Engineering

Background:

• Contact lenses offer a promising platform for wearable electronics.
• Miniaturized power sources are crucial for enabling sophisticated functionalities in smart contact lenses.
• Existing power solutions for contact lens devices are limited in scope and scalability.

Purpose of the Study:

• To demonstrate the first encapsulation of a flexible micro battery within a contact lens for eye-tracking applications.
• To explore methods for scaling the battery to power various embedded circuits (e.g., ASIC, photodiodes).
• To investigate the integration of the micro battery with external energy harvesting sources.

Main Methods:

• Fabrication of a ring-shaped micro battery with a surface area of 0.75 cm².
• Characterization of the battery's areal capacity (43 µAh·cm⁻² at 20C).
• Simulation of power consumption for a 0.35-µm CMOS ASIC.
• Functional demonstration by powering an orange LED.

Main Results:

• The fabricated micro battery achieved an areal capacity sufficient for powering a simulated ASIC for 3 minutes.
• The micro battery successfully powered an orange LED, demonstrating its functionality.
• The study outlines strategies for scaling the battery and integrating harvested energy.

Conclusions:

• The successful integration of a flexible micro battery into a contact lens represents a significant advancement for wearable eye-tracking technology.
• The developed power solution is scalable and compatible with various embedded electronic components.
• This work lays the foundation for self-powered, intelligent contact lens devices.