Vertical Stacked LEDs: MIT’s Simple Solution To Upgrade Digital Screen

In early 2023, the Massachusetts Institute of Technology announced that they’ve created a new way of making high-resolution digital displays. Their method, which involves stacking LEDs instead of placing them beside one another, may unlock even more detailed visuals. It’s especially important for VR and mobile – fields where smaller screens limit the detail that can be represented on-screen. Here are the details.

Our Current LED Technology

Right now, our screens function through adjacent micro-LEDs laid side by side. Each one is tiny, fitting into one pixel on your screen, with potentially millions of pixels making up the whole display. Each pixel uses the RGB color gamut for its microscopic LEDs, allowing it to simulate all colors.

As for what we use these micro-LEDs for – they’re everywhere. While they can simulate black-and-white spaces just like this text, the true test of these displays is often color and detail. In a world filled with growing digital entertainment industries, the demand for both is never-ending. iGaming is one of those industries which has a lot of color variation, plus detailed, animated elements on-screen. This can be seen with games that feature bingo jackpots like Eye of Horus or Monsters Unchained, both using high-detail animated grids filled with color to portray their themes. iGaming is also an industry that exists on mobile, where MIT’s advancements could benefit future gaming experiences. Without that kind of progress, we risk hitting a plateau for visual fidelity.

MIT’s New Breakthrough

So, if standard pixels are made by placing micro-LEDs next to each other, how did MIT make them even smaller? The technology used for pixels has reliably gotten smaller over time, with fears that they can only get so small while being useful to us. MIT’s solution to this problem sounds deceptively simple – place the micro-LEDs on top of one another, instead of side by side.

This saves a lot of real estate when you’re dealing in microns. The red, green, and blue LEDs are placed vertically, allowing them to generate multicolored visuals without getting in each other’s way. According to MIT, these new micro-LED pixels could be packed as tightly as 5,000 pixels per inch. That’s higher than commercial OLED screens that have a few hundred pixels per inch, though similar metasurface tests have demonstrated as much as 10,000 PPI. Jiho Shin, one of the researchers behind this project, said that “in theory we could reduce the pixel area by a third.”

How They Did It

While it may sound simple, a lot of logistics went into creating these prototype pixels in an MIT lab. It took an international team of researchers and methods that weren’t possible in the past, hence why we didn’t stack LEDs within pixels in the first place.

To simplify what was a very complicated process, they used two main methods. First is 2DLT – 2D Layer Transfer – where those researchers grew thin LED membranes and stacked them on each other. Those LED membranes were almost a submicron in thickness, with the complete pixel being just 4 μm – that’s 4 microns, where 1,000 microns create 1 millimeter.

The second method solved color quality concerns. They earmarked red, green, and blue to different voltages. A higher current will trigger red, for example, and then lower currents trigger the others. Shin highlights that by applying these currents together, a red and weaker blue color would produce pink. This way, the full spectrum of colors is unlocked.

Scalability Concerns

This new development in micro-LED tech, along with the 2DLT method in general, is very promising for future display technology. However, there are concerns that MIT admit they need to address.

With the potential for so many LEDs now, they’d all need to be controlled accurately. Shin says this can be as many as 25 million. The project outlines the use of very small silicone membrane transistors to help with this. However, per MIT’s own statement, this is what they’ll need to improve on in the future.