Scientist Lee Seok Woo said a scene from the movie “Mission: Impossible” inspired his latest invention: batteries for smart contact lenses.
In the fourth film in the series, an agent wears contact lenses capable of facial recognition and eye tracking. Lee wanted to make that lens a reality.
“I was thinking, 'How can I work in this field of smart contact lenses?'” the associate professor at Nanyang Technological University's School of Electrical and Electronic Engineering told CNBC's “The Edge.”
Lee's experience in battery components served as a starting point for his foray into wearable technology. He realized that smart contact lenses would need compact, safe batteries, which would be crucial to advancing the development of these devices.
The contact lenses themselves are extremely thin at 0.5mm, so the size and flexibility of these batteries are key to avoiding user discomfort.
“The thickness of our battery is about 0.2 mm, about twice the thickness of a human hair,” Lee said.
A demonstration of how a smart contact lens would fit into a human eye model.
Lauren Choo | CNBC
Lee and his team invented a battery that can run on a biocompatible saline solution as an alternative to lithium-ion batteries, which contain flammable materials.
This new battery can be charged by conventional cable method or chemical method. The battery is coated with glucose and when immersed in a saline solution, the glucose will react with sodium and chloride ions to charge it.
Scientists at NTU Singapore demonstrate how a smart contact lens battery can be charged using the conventional cable method.
Lauren Choo | CNBC
After eight hours of chemical charging, the battery can reach 80% of its total capacity. Then, it can be used for a couple of hours during the day.
However, there is another unusual way to power the battery.
“Tear solution also contains glucose. That means that while you're wearing contact lenses, your tears can also charge the battery,” Lee said.
“If you cry more, then you can charge your battery more.”
A scientist shows off a smart contact lens equipped with a working microbattery prototype.
Lauren Choo | CNBC
Currently, the battery capacity and voltage are still very low. Using the two methods, the battery can only produce a voltage of approximately 0.3 V – 0.6 V. The standard voltage for an AA battery is 1.5 V.
At this stage, that output is insufficient to power data storage or the Internet connection, but the team is working to develop battery specifications.
One potential partner Lee has identified is in the healthcare sector.
“We use glucose as biofuel. There are many diabetic patients who monitor their glucose level every day,” Lee said.
“We studied how we can detect the glucose level while the wearer is wearing contact lenses.”
Despite the possible prospects for such an innovation, Lee believes that costs should be kept low, taking into account the capacity of the batteries.
“Once it is seriously commercialized, the cost of the battery should be only a few dollars.”
