Researchers from the Georgia Institute of Technology and MIT have developed a new process based on 2D materials to create LED displays with smaller and thinner pixels. This new LED display should create clearer and more realistic virtual worlds when you wear your VR glasses. By vertically stacking freestanding, ultrathin RGB Led membranes they achieved the smallest pixel size reported to date and smallest-ever stack height.
If you put on a virtual reality headset, chances are that it looks like you are viewing the world through a screen door. The current flat panel displays use pixels that are visible to the naked eye, along with small bits of unlit dark space between each pixel. The result is a black, mesh-like grid that isn’t comparable to how we view the real world. Therefore, researchers from Georgia Institute of Technology and Massachusetts Institute of Technology (MIT) have developed a new process to create a LED display with smaller and thinner pixels.
LED display is LEDs stacked on top of each other
In a paper called ‘Vertical full-colour micro-LEDs via 2D materials-based layer transfer’ the researchers, along with co-authors from the Sejong University in Korea, and other institutes in Korea and the U.S, have presented a new process to create LED displays. In the new process LEDs are stacked instead of placing them next to each other. The result promises a future of clearer and more realistic LED displays.
Georgia Tech-Europe Professor Abdallah Ougazzaden and research scientist Suresh Sundaram (who both also hold appointments in Georgia Tech’s School of Electrical and Computer Engineering) collaborated with researchers from MIT. Together they’ve figured out that freestanding ultra-thin RGB LEDs can be stacked vertically. This way array density can be brought back to 5,100 pixels per inch. This is the smallest pixel size reported to date (4 microns) and the smallest stack height ever, while delivering a full commercial range of colors.
Based on Van der Waals epitaxy
According to a statement, this ultra-small vertical stack was achieved via a technology that’s called ‘Van der Waals epitaxy’ on 2D boron nitride developed at the Georgia Tech-Europe lab and the technology of remote epitaxy on graphene developed at MIT. The study showed that the world’s thinnest and smallest pixeled displays can be enabled by an active layer separation technology using 2D materials such as graphene and boron to enable high array density micro-LEDs resulting in full-color realization of micro-LED displays.
One unique facet of the two-dimensional, material-based layer transfer (2DLT) technique is that it allows the reuse of epitaxial wafers. Reusing this costly substrate could significantly lower the cost for manufacturing smaller, thinner, and more realistic displays. “We have now demonstrated that this advanced 2D, materials-based growth and transfer technology can surpass conventional growth and transfer technology in specific domains, such as in virtual and augmented reality displays,” said Ougazzaden, the lead researcher for the Georgia Tech team.
Next level virtual reality
These advanced techniques were developed in metalorganic chemical vapor deposition (MOCVD) reactors, the key tool for LED production at the wafer scale. The 2DLT technique can be replicated on an industrial scale with high throughput yield. The technology has the potential to bring the field of virtual and augmented reality to the next level, enabling the next generation of immersive, realistic micro-LED displays.
“This emerging technology has a tremendous potential for flexible electronics and the heterogenous integration in opto-electronics, which we believe will develop new functionalities and attract industry to develop commercial products from smartphone screens to medical devices,” Ougazzaden said.
