The first prototype of the liquid crystal bifocalsLin et al.APS 2025 Lenses made with liquid crystals could lead to eyeglasses that can easily switch between correcting near- and far-sightedness. Bifocal glasses date back to the 18th century, and their design has not fundamentally changed since.
Typically, the lower halves of their lenses are shaped for looking at objects that are close, while the upper halves are tailored for distant ones so a person wearing them must keep shifting their gaze, which can be uncomfortable. Yi-Hsin Lin at National Yang Ming Chiao Tung University in Taiwan and her colleagues built glasses that can switch between the two modes at the tap of a button.
Read moreThe critical computer systems still relying on decades-old code Instead of fashioning lenses just from glass, which must be made convex or concave depending on its function, the researchers filled them with a thin layer of liquid crystal. The crystals molecules bend light differently depending on their arrangement within the layer, and this can be controlled with electric fields.
Lin says the idea for switchable eyeglasses based on this principle, where thin electrodes in the frame would create the necessary electric fields, is almost 50 years old, but technical challenges stalled their development. Her team overcame some of these and made a wearable prototype.
*Reporting by Newscientist.*
