Screens have revolutionised how we communicate: starting with the humble cathode ray tube, which was developed to observe the motion of electrons on single colour images, to today’s smartphones that we use for work, leisure and everything in between.
The next frontier for the screen would be to shrink it even further. To have foldable screens that could behave like newspapers did in Harry Potter, or even be worn as clothes that never go out of fashion. And while there’ve been many interesting approaches to achieve such feats, they have always posed serious limitations.
Now, Debashis Chanda of the University of Central Florida and his team may have overcome one such critical limitation—with technology that can be used to build a flexible and ultra-thin display.
Right now, however, the screen is only reflective. That is to say that it does not produce any light of its own. Instead, light reflected by it in different ways creates the “display.”
“If we can change the colour and pattern of a surface, many such things, like instantly changing colour of a dress, are achievable,” Kolkata-born Chanda, who studied at Jadavpur University, told Quartz.
Like an animal
The inspiration behind developing such a technology came from nature.
“We can see colour everywhere in nature. Animals like chameleons, octopuses, and so on, can create colour and pattern on their thin skin just based on ambient light,” he said. ”Unlike our bulky, brittle displays, their colour-generating mechanism is flexible and thin.”
Chanda’s approach was to build on previous work in the field of plasmonics, which exploits the interaction between light and electrons in metal surfaces. In metals, electrons are relatively loosely held compared to other elements. When light, which is a form of energy, falls on these electrons, it can cause them to become excited. As they fall back to their previous state, they release the light back, sometimes with a change in the nature of the light (different colour, different phase, etc.)
So, in effect, such a surface selectively absorbs some portion (red, green, blue) of incident white light—and, as a result, the reflected light from the surface gives the perception of colour to the surface. Using this quirk, scientists have built displays that are ultra-thin and can show images in very high resolution. However, the technology restricts displays from being useful. Once manufactured, they only show one image.
Chanda’s solution to solving this problem was to add another layer on top of a generic display. This layer of liquid crystals could be controlled by changing the voltage applied to it and thus, the display as a whole could be changed to show any image (albeit reflectively). The results of Chanda and his team’s work were published in Nature Communications in June.
As an example, Chanda recreated the iconic photograph of the sea green-eyed Afghan girl peering from the National Geographic magazine cover in 1985.
And because Chanda’s display is ultra-thin and doesn’t require a big source of energy, using it in clothes is a possibility. The next step would be to create displays that can create their own light, instead of relying on reflection. It’s no easy feat, but if achieved we could all soon have a copy of the Harry Potter newspaper, the Daily Prophet, and clothes that can keep up with ever-changing fashion trends.