A research team at the University of Minnesota has 3D printed an image sensor array onto a hemispherical surface for the first time, taking a big step towards the creation of a bionic eye that could help blind or partially-sighted people see.
Using a custom-built 3D printer, the team laid down a base layer of silver particles onto the surface of a hemispherical glass dome. The silver particles stayed in place and dried uniformly instead of running down the curved surface. They then used semiconducting polymer materials to print photodiodes (tiny devices that convert light into electricity) on top of the silver base. The resulting prototype ‘bionic eye’ was able to convert light to electricity with 25 per cent efficiency.
“Bionic eyes are usually thought of as science fiction, but now we are closer than ever [to making them a reality] using a multi-material 3D printer,” said Professor Michael McAlpine of the University of Minnesota. “We have a long way to go to routinely print active electronics reliably, but our 3D-printed semiconductors are now starting to show that they could potentially rival the efficiency of semiconducting devices fabricated in microfabrication facilities. Plus,we can easily print a semiconducting device on a curved surface.”
The team plans to create a second prototype with more light receptors and develop a method of printing onto a soft hemispherical material that can be implanted into an eye socket.
This is an extract from issue 328 of BBC Focus magazine.
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