Minimal pixels achieve the highest possible resolution visible to the human eye

"This means that each pixel roughly corresponds to a single photoreceptor in the eye, i.e. the nerve cells in the retina that convert light into biological signals. Humans cannot perceive a higher resolution than this," says Andreas Dahlin, Professor at the Department of Chemistry and Chemical Engineering at Chalmers. 

The retina E-paper can be placed very close to the eye. To demonstrate the technology's performance, researchers recreated an image of Gustav Klimt’s famous artwork ‘The Kiss’ on a surface area of approximately 1.4 × 1.9 millimetres. By way of comparison, this means that the image was 1/4000th that of a standard smartphone. 

As in previous research led by Andreas Dahlin, the screen is passive, meaning that it does not contain its own light source; instead, the colours of the pixels appear when ambient light hits small structures on a surface. The same principle can be found in the magnificent plumage of small birds. The ultrasmall pixels contain particles of tungsten oxide. By adjusting the size of the particles and how they are positioned in relation to one another, the researchers have succeeded in controlling how the colours in light are diffused and reflected, thereby creating pixels in the colours red, green and blue, which can then be used to generate all colours. By applying a weak voltage, the particles can be ‘switched off’ and they will turn black. 

"This is a major step forward in the development of screens that can be shrunk to miniature size while improving quality and reducing energy consumption. The technology needs to be fine-tuned further, but we believe that retina E-paper will play a major role in its field and will eventually have impact on us all," says Giovanni Volpe, Professor at the Department of Physics at the University of Gothenburg.