Scientists have created a screen with pixels a million times smaller than those of a smartphone

Smartphone makers may soon not have much to boast about the number of pixels they can place on a pocket screen. Researchers at the University of Cambridge have developed a way to create pixels a million times smaller than those used even on Apple's Retina displays. But the extreme pixel density is somehow the least interesting part of this advance.

Pixels are created by first coating microscopic gold particles (a few billion meters) of an electroactive polymer called polyaniline, able to modify its structure in the presence of electric fields. It is done in a tank where the polymer and the gold particles are mixed, then the results are simply sprayed on a plastic film covered with a mirror finish. This seems to be a surprisingly simple process, and it turns out that one of the best features of this new technology is that it is relatively easy and inexpensive to manufacture.

Instead of exciting a chemical material to emit photons, the light ends up being trapped between these microscopic gold particles and the reflective medium to which they adhere. But despite the small size of the pixels, they end up producing a glow that appears much larger and brighter to the human eye even in direct sunlight. The colors of each pixel can also be adjusted across the spectrum by applying a specific electrical current that modifies the polymer coating of each gold particle. Once modified, each pixel will retain its color indefinitely, so that a constant power supply is not needed. Thus, in addition to being affordable and flexible to manufacture, this new technology is also inexpensive to operate.

But to what extent do these screens of gold dust replace other technologies such as LCDs and OLEDs? Researchers at the University of Cambridge have suggested potential applications such as large-sized building screens, an architecture that could change in appearance without the need for paint, or even clothes that could actively camouflage the building. Carrier in the same way that octopus or cuttlefish can hide in their environments, that is, they are considering applications that might be inappropriate for fragile traditional displays.

But is the refresh rate fast enough to display a moving video? Can individual pixels be controlled with sufficient precision to produce recognizable images? The team is currently looking for partners to contribute to the development of their creation, and answers about the scope of its applications may not be resolved for some time.