Researchers in Sweden have create a tiny display with a resolution of beyond 25,000 pixels per inch. The team consists of researchers from Chalmers University of Technology, the University of Gothenburg and Uppsala University in Sweden have created what they are calling Retina e-paper, which could have significant benefits for building incredibly realistic VR scenarios.
The screen is about the size of the human pupil.
Pixels reproduce colours using nanoparticles whose dimensions and arrangement control how light is scattered, and whose optical properties can be electrically tuned. This paves the way for the creation of virtual worlds almost indistinguishable from reality.
The researchers reproduced The Kiss painting by Gustav Klimt as part of a demonstration where the image was shown in perfect resolution on the screen, which at approximately 1.4 x 1.9 mm was 1/4000th that of a standard smartphone.
The team has created 'tunable metapixels' made from tungsten oxide, a material that can switch from being an insulator to a metal based on its electrical state. The metapixels reflect light differently based on their size and how they're arranged, and can be manipulated by an electrical current.
The research has been published in the scientific journal Nature states; "As demand for immersive experiences grows, displays with smaller sizes and higher resolutions are being viewed increasingly closer to the human eye. As the size of emitting pixels shrinks, the intensity and uniformity of their emission are degraded while colour cross-talk and fabrication complexity increase, making ultra-high-resolution imaging challenging.
"By contrast, electronic paper, which uses ambient light for visibility, can maintain high optical contrast regardless of pixel size, but cannot achieve high resolution. Here we demonstrate electronic paper with electrically tunable metapixels down to ~560 nm in size (>25,000 pixels per inch) consisting of WO3 nanodisks, which undergo a reversible insulator-to-metal transition on electrochemical reduction.
"This transition enables dynamic modulation of the refractive index and optical absorption, allowing precise control over reflectance and contrast at the nanoscale. By using this effect, the metapixels can achieve pixel densities approaching the visual resolution limit when the display size matches the pupil diameter, which we refer to as retina electronic paper.
"Our technology also demonstrates full-colour video capability (>25 Hz), high reflectance (~80%), strong optical contrast (~50%), low energy consumption (~0.5–1.7 mW cm–2) and support for anaglyph 3D display, highlighting its potential as a next-generation solution for immersive virtual reality systems."