New technology gives digital displays advanced features
Researchers at Linköping University have developed a completely new type of display whose LEDs can contain sensors as well as absorb and emit light - in a single layer.
Researchers at Linköping University have now succeeded in developing a digital screen where the light-emitting diodes themselves have more functions than just emitting light - they can also react to touch, light, fingerprints, and detect the user's pulse.
The technology means that all sensors can now be baked into a single layer in the screen, something that today requires several different layers of technology for various functions, for example one for light, one for touch/gesture/motion. In the new technology, all sensor functions are embedded in the screen's light-emitting diodes, so-called perovskite LEDs - PeLED.
The crystalline material perovskite has a strong ability to both emit and absorb light, which opens up for the new possibilities. The screen created from the material can react to both light and touch, but the device can also be charged as a solar cell due to the material's ability to receive light.
Manufacturing of PeLED.Thor Balkhed
- There is a great potential for a new generation of digital displays where new advanced features can be created. From now on, it's about improving the technology into a commercially viable product. For example - the screen of your smartwatch is off most of the time. During the screen's off time, it could instead absorb light to charge the watch, significantly extending the time between charges, says Chunxiong Bao, Associate Professor at Nanjing University and former postdoc at Linköping University.
"Proof of concept" for the new PeLED. The image shows the electroluminescence spectrum for PeLED, screen concept, schematic demonstration of touch function, pixel mapping, and touch function for input on the screen.From the article A multifunctional display based on photo-responsive perovskite light-emitting diodes
Another advantage of the new technology is the ability to display all colors that exist within the visible light spectrum with a single perovskite LED. Today, three LEDs are required, a red, a green, and a blue, which make up the RGB color space that a screen displays, by mixing the three colors at different intensities to thus produce the correct color hue.
Although the concept works, there are still some issues to be resolved before the screen becomes commercial. Among other things, the lifespan of the perovskite light-emitting diodes needs to be longer; currently, the screen can only be kept on for a few hours before the material becomes unstable and the diodes go out.
However, the researchers believe that many of the problems will be solved within ten years.
