Maximizing Resolution: The Power of Minimal Pixels

With the increasing complexity of information transfer in society, the need for high-precision image and video transmission screens is on the rise. Researchers from Chalmers University of Technology, the University of Gothenburg, and Uppsala University in Sweden have introduced a screen technology featuring the smallest pixels ever created, offering the highest resolution discernible by the human eye.

The color reproduction in these pixels is achieved through nanoparticles that control light scattering based on their dimensions and arrangement, with their optical properties being electrically adjustable. This groundbreaking technology, detailed in a published paper in Nature, opens the door to creating virtual worlds that are virtually indistinguishable from reality.

Kunli Xiong, Associate Senior Lecturer/Assistant Professor at the Department of Materials Science and Engineering at Uppsala University, the project’s originator and lead author of the study, commented, “The technology we have developed offers new ways to interact with information and the environment around us. It has the potential to expand creative boundaries, enhance remote collaboration, and even accelerate scientific research.”

Pixel size and quantity determine resolution, affecting how realistic images and videos appear on screens. In virtual or augmented reality settings where screens are small and close to the eye, the current pixel limitations hinder the experience due to their inability to be reduced beyond a certain size. For instance, on a micro-LED screen, pixels lose effectiveness when smaller than 1 micrometer.

To address this challenge, researchers have introduced retina E-paper, a novel reflective screen technology. Each pixel measures approximately 560 nanometers, with the total screen area comparable to the human pupil’s size, boasting a resolution exceeding 25,000 pixels per inch (ppi).

“Each pixel essentially corresponds to a single photoreceptor in the eye, which are the nerve cells in the retina converting light into biological signals. Human perception cannot distinguish resolutions higher than this,” explained Andreas Dahlin, Professor at the Department of Chemistry and Chemical Engineering at Chalmers.

Retina E-paper can be positioned very close to the eye. To showcase its capabilities, researchers recreated Gustav Klimt’s renowned artwork “The Kiss” on a surface of about 1.4 × 1.9 millimeters, making the image 1/4000th the size of a standard smartphone display.

Similar to previous research led by Dahlin, the screen is passive, meaning it lacks its light source. Instead, pixel colors appear when ambient light interacts with small structures on the surface, akin to the colorful plumage of small birds.

The ultrasmall pixels in retina E-paper contain tungsten oxide particles. Through adjusting the particles’ size and arrangement, researchers have effectively controlled light diffraction and reflection to create red, green, and blue pixels, enabling the display of all colors. Applying a weak voltage “turns off” the particles, rendering them black.

Giovanni Volpe, Professor at the Department of Physics at the University of Gothenburg, added, “This advancement marks a significant stride in shrinking screen sizes while enhancing quality and reducing energy consumption. Although further refinement is necessary, we anticipate retina E-paper will revolutionize the field and eventually impact us all.”