Technique turns car windows into computer displays

Glasgow University researchers are helping to develop a technique that aims to turn car windows into computer displays and create more efficient smartphone screens.

The scientists are part of a Europe-wide project, also involving Fiat and glass maker Saint-Gobin, that aims to commercialise a method of creating three-dimensional nanostructures on the surface of glass to affect the brightness and direction of light.

This nano-imprinting lithography technique could help to create the next generation of ’head-up displays’ (HUDs) on the windshields of cars and aircraft — that emit their own light rather than using a projector — in order to display information to the driver.

It could also be used to develop windows that maximise the amount of light they let in and to create brighter LEDs and computer displays that use less energy.

‘The technology has never quite broken through in microchips because the number of defects is too high, but it’s an ideal application for optical properties such as light displacement,’ Glasgow’s Dr Nikolaj Gadegaard told The Engineer.

‘The defects won’t necessarily affect the way the light comes out. We’re working at around 100nm, so the eye won’t pick up defects at this scale.’

The technique typically involves creating a stamp that is pressed into a heated polymer to leave an impression of the 3D nanostructure. The NaPANIL project aims to create a scalable way of recreating this method with glass.

As part of the project, Fiat is hoping to use nano-imprinting on a car windscreen to produce an emissive head-up display (eHUD) that provides the driver with speed and direction information without having to look down at the dashboard.

Light would enter the windshield from LEDs at its edge and travel through the glass until the nanostructure released it in the right place — a more energy-efficient method than projecting images onto the window.

‘A lot of light doesn’t want to come out of glass, so we need to create a structure that can pull light out as efficiently as possible,’ said Gadegaard. ‘If we then put the structure on an LED, we could get a two- or threefold increase in brightness.’

Another part of the project therefore aims to use the technique to create brighter, more efficient LED screens. A third element involving Saint-Gobin has set out to create windows that improve natural lighting and reduce the need for electric lights.

One of the biggest challenges for the project is finding a way to produce the stamp to manufacture the pattern quicker and more cheaply.

One idea that could be useful when the nanostructure pattern is replicated over a wide area would be to create a stamp representing one unit of the pattern and repeat the imprinting process over and over — much quicker than making a larger stamp.

The project is due to end in May 2012, by which time the participants hope to have created a prototype technology for the eHUD and the brighter LEDs.