Imagine a future where your contact lenses are not just for vision correction but also smart enough to connect to your devices, display information, and more. Even better, these lenses could be powered by something as simple and natural as your tears. Researchers at Nanyang Technological University (NTU) in Singapore have created a groundbreaking new battery that can charge using human tears. This innovation could change how smart contact lenses work in the future.
What Makes This Battery Different?
Traditionally, smart contact lenses need a battery to power features like augmented reality displays. However, these batteries often contain metals and wires that can be risky for the eyes. The NTU team, led by Professor Lee Seok Woo, developed a unique, micrometer-thin battery that doesn’t use any metals. Instead, it uses biocompatible materials and a glucose-based coating that reacts with sodium and chloride ions found in tears to generate electricity.
This means the battery can charge as you wear the lenses. The approach is safer for both the user and the environment because it relies on natural, safe substances like glucose and water.
How Does It Work?
The key to this battery’s design is the way it interacts with the body's natural fluids. When the battery is worn in the eye, the ions in your tears interact with the materials in the battery, producing the energy needed to power the lens. The researchers even found that the battery could be recharged by storing it in a saline solution with high levels of glucose, potassium, and sodium ions.
Professor Woo explained that the goal was to create a battery that could charge both sides of the battery at once. This was a major improvement over previous methods, which only charged one side of the battery. The result is a more reliable and efficient system.
How Much Power Does It Produce?
The new battery is very thin—less than a millimeter thick—but still packs enough power to run smart lenses for most of the day. The battery can produce a current of 45 microamperes and a maximum power of 201 microwatts. When stored in a simulated tear solution, the battery can even last an extra hour for every 12 hours it’s used.
What’s even better is that the battery can handle up to 200 charge-discharge cycles, meaning it will last for a decent amount of time before needing to be replaced. This is an important factor when considering the longevity and practicality of the battery in everyday use.
The Future of Smart Lenses
The team is currently working to improve the battery’s performance, especially in terms of the amount of electricity it can discharge. They are also partnering with contact lens companies to bring this technology to market.
With this new battery, the need for bulky wires or wireless components is eliminated, making it a great fit for the compact space of a contact lens. The electrodes are placed on the outside of the lens, ensuring they don't obstruct your vision.
Why Does This Matter?
This innovation is a big step forward for wearable tech. It shows that we can create smaller, safer, and more sustainable power sources for devices that are close to the body. As this technology improves, we could see smart contact lenses that not only enhance vision but also provide exciting new features without worrying about harmful materials or frequent charging.
This research opens the door to many possibilities for the future of smart lenses, making them more practical, efficient, and safer to use.
Source:
https://www3.ntu.edu.sg/CorpComms2/Research%20Papers/tearbased.pdf
https://interestingengineering.com/innovation/smart-contact-lenses-with…
https://www.ntu.edu.sg/docs/default-source/academic-services/ntu-singap…
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