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Scientists have created an ultra-thin battery for smart contact lenses that is charged by our own tears. The battery is wafer-thin at 0.2mm, approximately twice the thickness of a human hair, and it fits comfortably within the standard contact lens thickness of 0.5mm.
Lee Seok Woo, a scientist, shared that a “Mission Impossible” movie scene sparked the idea for his invention—batteries for smart contact lenses. In the movie’s fourth installment, an agent uses contact lenses that have capabilities such as facial recognition and eye tracking. Inspired by this, Lee aimed to turn this fictional technology into reality.
Researchers in Singapore have developed an ultra-thin battery that can be embedded onto your contact lenses.
The battery, which may even be powered by your tears, has made "Mission Impossible"-style smart contact lenses one step closer to reality. pic.twitter.com/wlp45fwtLK
— CNBC International (@CNBCi) June 6, 2024
Reflecting on his motivations, Lee, an associate professor at Nanyang Technological University’s School of Electrical and Electronic Engineering, told CNBC’s “The Edge,” “I was thinking, ‘How can I work in this field of smart contact lenses?'”
His background in battery components got him into wearable technology. Lee recognized that smart contact lenses would require safe and compact batteries, which are essential for the future development of these devices.
How can the battery of smart contact lenses be charged by tears?
The battery is powered by a “biocompatible saline solution” instead of a typical lithium-ion battery used in smartphones and smartwatches, which would not be safe for a product such as a contact lens.
This battery has a traditional wired charging method, as well as a chemical process. It includes a glucose coating and, after being dipped in saline, reacts with the sodium and chloride ions to generate power.
Chemically charging the battery for eight hours enables it to keep 80 percent of its maximum capacity, after which it can function for several hours. In addition, an alternative and unique power source is available.
“Tear solution also contains glucose. That means, while you’re wearing the contact lens, your tears can also charge the battery,” explained Lee. “If you cry more, then you can charge your battery more.”
At present, the battery’s capacity and voltage are relatively low, producing only about 0.3V – 0.6V, whereas a standard AA battery delivers 1.5V.
The current output is not enough to enable data storage or internet connectivity, but efforts are underway to improve the battery’s performance.
Lee sees potential applications in the healthcare sector. “We use glucose as a biofuel. There are many diabetic patients who check their glucose level every day,” Lee stated. “We studied how we can detect glucose level while the user is wearing the contact lens.”
Despite the promising aspects of this technology, Lee believes it is crucial to maintain low production costs due to the limited battery capacity. “Once it goes into very serious commercialization, the cost of the battery should only be a few dollars,” Lee stated.
Featured image: Canva
