An eye for detail

US researchers have developed a flexible light-sensitive material that could be used to mimic the functionality of the retina.


Researchers at the Electrical and Computer Engineering department of the University of Wisconsin-Madison have developed a flexible light-sensitive material that could be used to mimic the functionality of the retina at the back of the human eye.


Such a material, when used to build an imaging sensor, could help to eliminate the problems of distortion that have plagued conventional cameras fitted with lenses and flat imaging devices.


Inspired by the human eye, Associate Prof Zhenqiang (Jack) Ma and his colleagues created the curved photodetectors with specially fabricated nanomembranes made from sheets of light-sensitive germanium, which were then applied to a polymer substrate, such as a thin, flexible piece of plastic.


Currently, the group has demonstrated photodetectors curved in one direction, but Ma hopes to develop hemispherical sensors.


‘We can easily realise very high-density flexible imaging arrays, because the photodetector material germanium itself is extremely bendable and extremely efficient in absorbing light,’ said Ma.


Ma’s team aren’t the only ones interested in developing such devices. Last year, The Engineer Online reported on the development of a hemispherical ‘eye’ camera using an array of single-crystalline silicon detectors and electronics, configured in a stretchable, interconnected mesh.


Built by researchers at the University of Illinois and Northwestern University, the camera integrates a hemispherical detector with a hemispherical cap and imaging lens to yield a system with the overall size, shape and layout of the human eye.