Quick color-changing lenses catch military’s eye

Ashley N. Paddock, ashley.paddock@photonics.com

Lenses that change color rapidly based on the amount of voltage passing through them could have important military and civilian applications as well as uses for energy-saving windows and custom fabrics.

Color-changing lenses normally use a photochromic film, or a sheet of polymers that change color when light hits them. Now, electrochromic lenses, developed by professor Greg Sotzing of the University of Connecticut, are controlled by electric currents passing through them when triggered by a stimulus such as light. Findings appeared in the July issue of the Journal of Materials Chemistry (doi: 10.1039/C1JM11141H).

The electrochromic lenses consist of a mixture of polymers – or “goop,” as Sotzing calls it – that is squirted between two layers, creating a lens as it hardens. The polymer mixture used in the lens is less expensive to produce than previous mixtures and creates less waste, he said.

A new lens material developed at the University of Connecticut can change color and has attracted the interest of the US military. Courtesy of UConn.

Because the material changes color almost instantaneously, the glasses have military applications that would allow a soldier’s goggles to instantly adapt to different lighting conditions. For example, if a person were to emerge from a dark passageway and into the desert, the color-changing lens would complement the surroundings quickly, potentially saving the life of some soldiers.

UConn has created Alphachromatics Inc. with Sotzing and postdoc Michael Invernale of MIT in Cambridge to test the lenses’ potential use for custom fabrics and energy-saving windows. The university has a patent pending for the technology, which currently is under option to the company.