Adjusting Glasses

(Taken from Weekly Science News) A new type of eyeglasses with electrically adjustable focus might someday render bifocals and reading glasses obsolete, the device's inventors say. So far, the researchers have made a battery-powered prototype with close-up focus that flicks on and off with a switch.

Future versions of the eyeglasses may incorporate a distance sensor to automatically adjust the focus as the viewer's gaze changes between far and near viewing, says one of the inventors, electrical engineer David L. Mathine of the University of Arizona in Tucson.

To make eyeglass lenses that change focus electrically, the researchers created sandwiches of glass sheets separated by a fluid layer 5 micrometers thick. The filling consists of a transparent substance, a type of liquid crystal, that's made up of rod-shaped molecules suspended in a liquid. The team used precise computer-chip–manufacturing methods to apply a bull's-eye pattern of transparent electrodes to the inner surface of one of the glass sheets.