Researchers in the Republic of Korea showed that a specific mixture of carbon molecules, polymers and solvent can be used to print a supercapacitor’s electrodes onto a lens with micron-scale precision via a technique called direct ink writing. The same process deposits a UV-cured ionic liquid that functions as the supercapacitor’s electrolyte. As a proof-of-concept, the work could one day lead to smart contact lenses with sensors for health monitoring, or with integrated displays for augmented reality applications...

Trailing wires from one’s eyes to a battery pack is obviously unacceptable, so smart lenses will need a store of electrical charge incorporated into the lens, as well as a way to replenish it wirelessly. For Jang-Ung Park of Yonsei University, Sang-Young Lee of Ulsan National Institute of Science and Technology (UNIST) and colleagues, the solution was to integrate a miniature, flexible supercapacitor and an energy-harvesting antenna to recharge it...

“Commercial supercapacitors are composed of sheet-type components that are stacked in fixed cylindrical or rectangular cases, which make them too bulky and rigid to fit into a tiny, soft smart contact lens,” explains Park. “The breakthrough was to make the supercapacitor components printable in an ink form. The component inks were drawn around the edge of the smart contact lens, so they won’t block the optical view of the user.”

Science fiction readers are fortunate to have had this idea presented to them several years ago. In his 2001 novella Fast Times at Fairmont High, sf writer, computer scientist and mathematician Vernor Vinge described a near-future world in which everyone used smart contact lens displays. In his 2006 novel Rainbows End, set in the same milieu, he describes them this way:

Miri... leaned her head forward, and stuck a finger close to her right eye. "You already know about contacts, right? Wanna see one?" Her hand came away from her eye. A tiny disk sat on the tip of her middle finger. It was the size and shape of the contact lenses he had known. He hadn't expected more, but... he bent closed and looked. After a moment, he realized that it was not quite a clear lens. Speckles of colored brightness swirled and gathered in it. "I'm driving it at safety max, or you wouldn't see the lights." The tiny lens became hazy, then frosty white. "Uk. It powered down. But you get the idea.."
(Read more about Vinge's smart contact lenses)