In a darkened corner of Nanosys‘s suite here at CES 2025 in Las Vegas was a tiny watch-sized prototype display. At first glance, it didn’t seem particularly special. It was bright, for sure, and definitely colorful. The watch band was fake, and it was all embedded in a box that was undoubtedly helping it function in some way. Even using a jeweler’s loupe, there weren’t any outward signs that this was one of the most exciting next-gen display technologies. And yet, it was.
This new MicroLED goes further into the skinny end of the electromagnetic spectrum than competing types by incorporating four ultraviolet LEDs per pixel. By contrast, most LED-based displays on the market today use some version of blue LED, plus red and green quantum dots, to create the red, green and blue you need to create an image. Many other displays use phosphors instead of quantum dots, while a few use red, green and blue LEDs.
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If this seems weird it’s because it is. It’s also, as you’ll see, exceedingly clever. It might even drive down the currently exorbitant cost of MicroLED displays. Here’s what I learned.
UV LED
Different ways to create a MicroLED display, with the associated theoretical pros and cons: Left is just red, green and blue LEDs. In the middle, blue LEDs create blue light and excite red and green quantum dots. On the right, UV LEDs excite red, green and blue quantum dots. The fourth subpixel is a spare to help improve yields.
First, and this was one of my questions as well, yes, this is safe. You might have read or heard some stories from the last few years where industrial-grade UV lighting was used incorrectly, which led to skin and eye damage. One of the incredible things about quantum dots is that they convert light to different wavelengths almost perfectly. What little UV is left after most of it is converted by the QDs to some other color is blocked by the glass of the display and a filter.
Using UV LEDs in a MicroLED display has multiple benefits, though they’re perhaps not as world-changing as adding quantum dots to OLED or a whole new tech like nanoLED. It’s mostly on the manufacturing side. MicroLED is one of the newest display techs, and while it has a lot of promise, it’s currently quite difficult to manufacture. That’s one of the reasons MicroLED displays are so expensive.
If you strip out all the bits and bobs, at its core a typical MicroLED display is made up of millions of red, green and blue LEDs. Three of these are placed together to form each pixel. Without diving too far into the deep end, let’s just state the obvious that this is difficult to do. Using different red, green and blue LED materials presents certain manufacturing challenges. Challenges that using all blue LEDs and adding red and green quantum dots helps partially alleviate.
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Using UV LEDs goes one step farther. Instead of blue LEDs creating blue light and exciting red and green QDs, UV light excites red, green and blue QDs. So every subpixel is the same, just with a different flavor of QD on top. This reduces complexity and, theoretically, increases yields and thereby reduces manufacturing costs. Blue quantum dots aren’t nearly as commonly used as red and green. The beauty of quantum dots is that making them different sizes, which is what determines what wavelength (color) they emit, is relatively easy. Easier, in theory at least, than using different LED materials for different subpixel colors. Using UV LEDs introduces its own challenges, but according to pro-UV LED companies like Applied Materials, these are potentially easier to overcome.
Another interesting aspect of this method, at least as currently implemented, is using four subpixels instead of three. Because of the relatively high likelihood of dead pixels for any MicroLED display, having a “spare” subpixel to use in case one of the red, green or blue subpixels isn’t working, has the potential to increase yields. A dead subpixel would be found in the manufacturing process, and whatever subpixel color isn’t working would get a spray of that color. While this fourth subpixel would increase the overall cost of this aspect of production by 33% or so, researchers are estimating it would improve yields enough that it would be more than worthwhile.
This diagram shows the various stages used to build MicroLED displays using UV LEDs. The UV LEDs are mounted to the backplane, four for each pixel, and each has its own “bucket” that will hold quantum dot material. An ink-jet printer deposits said material into the bucket. As precise as this is, some “ink” spills out of the correct bucket (a). By turning on that subpixel, the UV light created cures the ink into place (also a). The surface is washed, removing the spilled ink (b). The process is repeated for green and blue (c-f). If, during this process, a computer detects one of the sub-pixels isn’t activating, the 4th spare subpixel gets called into action, receiving the dead subpixel’s ink color (g). The final stage (h) sees the entire unit covered and secured for further manufacturing and assembly.
Another potential boon for the manufacturing process is being able to self-cure. Some manufactures would like to use ink-jet printing for small MicroLED displays, as there are potential cost benefits. This method works on larger displays, but MicroLEDs are, well, micro. Using a different formulation in the QD “ink,” a color can be deposited on the substrate, cured by its own LED because it emits UV, and then any spillover of that color QD ink onto an adjacent subpixel can be washed away before the next subpixel gets its color sprayed on (see diagram above). So each subpixel only has the QDs for its color even if the ink-jet itself isn’t perfectly precise, improving color accuracy and performance. Something about the efficiency of a pixel curing itself makes my brain happy.
The display
The UV MicroLED prototype, built by CTC, mocked up to look like a smartwatch. It has 300dpi.
Which brings us back to Las Vegas and this bright, tiny display. As you can probably tell from the images, it’s mocked up to be a smartwatch display. With a brightness of up to 1,000 nits, it was plenty bright in a dark room. CTC, the manufacturer and part of the Foxconn group, estimates that in full production it might be able to get 3,000 nits.
Why, you might ask, would you need a 3,000-nit smartwatch if you’re not trying to signal passing spacecraft? To shine it in your eyeballs. One of the big potential uses for MicroLED is for AR and VR headsets, where tiny, efficient, extremely high resolution displays are vital. It’s also like your TV — it’s not always putting out its maximum brightness. Having that brightness potential opens up a wider range of possibilities.
Future displays
Still in the prototype stage, a production display would be brighter and potentially used in other devices like AR/VR headsets and more.
The question is always, “When does it come out?” That’s a bit hard to answer beyond, “not right now.” MicroLED in general and UV MicroLED specifically are both in the early stages of their development. There are MicroLED displays on the market, but it’s clear a lot of companies want a lot more MicroLED displays on the market. The trend is towards ditching LCD and OLED all together, but then again I’ve been writing about the death of LCD for over a decade, so who knows. We’ll likely see more of these later in the year and at next year’s CES for sure.
As well as covering audio and display tech, Geoff does photo tours of cool museums and locations around the world, including nuclear submarines, aircraft carriers, medieval castles, epic 10,000-mile road trips and more.
Also, check out Budget Travel for Dummies, his travel book, and his bestselling sci-fi novel about city-size submarines. You can follow him on Instagram and YouTube.