Researchers made the glasses using electrochromic materials that change transparency depending on the electric current. Many groups, including the UW, are developing such materials for so-called "smart windows" that could soon be used in energy-efficient homes and offices. Most smart windows use liquid-crystal technology or inorganic oxides. Those materials are expensive to produce and require a constant or frequent injection of power to hold their tint. The UW glasses are based on a new type of smart window using organic, rather than inorganic, oxides. These are cheaper to manufacture and require less power.
The prototype glasses are powered by a watch battery that attaches to the glasses frame, and the wearer spins a tiny dial on the arm of the glasses to change color or shade. The lenses were created by sandwiching a gel between two layers of electrochromic material. Applying a small voltage moves charged particles from one layer to another, and changes the transparency. Once the glasses are a certain tint they will stay that way without power for about 30 days. A single watch battery is able to power thousands of transitions, Xu said.
Organic molecules allowed the researchers to create colored lenses.
"In organic materials, the elements are simple but the structure is much more complicated," Xu said. "We can add more branches to this structure and tune in colors."
The prototype glasses change from dark blue to light blue. Xu and her colleagues have developed other adjustable lenses in red and yellow. In the future, they will layer sheets to create a range of colors in a single pair of shades.
"These are a little homemade," Xu said of the prototype, a modified pair of lab goggles. She plans to incorporate the lenses in more fashionable frames. Xu's group has a number of p
'"/>
Contact: Hannah Hickey
hickeyh@u.washington.edu
206-543-2580
University of Washington
27-Mar-2007