This Next-Gen MicroLED Prototype Is So Cool It’s Ultraviolet (Literally)
In a darkened corner of Nanosysthe apartment of here on CES 2025 in Las Vegas was a small watch-sized prototype. At first glance, it didn’t seem too special. It was bright, sure, and definitely colorful. The watch strap was fake and the whole thing was built into a box that no doubt helped it function in some way. Even using a jeweler’s loupe, there were no outward signs that this was one of the most exciting next-generation display technologies. And yet it was.
This new MicroLED goes further into the thin end of the electromagnetic spectrum than competing types by incorporating four UV LEDs per pixel. In contrast, most LED-based displays on the market today use some version of a 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 some use red, green, and blue LEDs.
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If this seems strange, that’s because it is. It’s also, as you’ll see, extremely clever. It may even bring down the exorbitant cost of MicroLED displays. Here’s what I learned.
UV LEDs
Different ways to make a MicroLED display with the associated theoretical pros and cons: On the left are only 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 spare to help improve yields.
First, and this was also one of my questions, yes, it is safe. You may have read or heard some stories from the past few years where industrial UV lighting has been misused, resulting in skin and eye damage. One of the amazing things about quantum dots is that they convert light into different wavelengths almost perfectly. The little UV that remains after most of it is converted by the QD to some other color is blocked by the display glass and filter.
Using UV LEDs in a MicroLED display has numerous advantages, although they may not be as world-changing as adding them quantum dots to OLEDs or an entirely new technology such as nanoLED. This is mostly on the production side. MicroLED is one of the newest display technologies and although it holds a lot of promise, it is currently quite difficult to manufacture. This is one of the reasons why MicroLED displays are so expensive.
If you strip away all the bits and bobs, at its core, a typical MicroLED display consists 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 hard 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 to partially alleviate.
The use of UV LEDs goes one step further. Instead of blue LEDs creating blue light and exciting red and green CTs, UV light excites red, green and blue CTs. So each subpixel is the same, just with a different flavor of QD on top. This reduces complexity and, theoretically, increases yields and thus lowers production costs. Blue quantum dots are not used as often as red and green ones. The beauty of quantum dots is that making them different sizes, which determines what wavelength (color) they emit, is relatively easy. Easier, at least in theory, than using different LED materials for different subpixel colors. Using UV LEDs creates its own challenges, but according to pro-UV LED companies like Applied materialsthey are potentially easier to overcome.
Another interesting aspect of this method, at least as currently implemented, is the use of four subpixels instead of three. Because of the relatively high probability of dead pixels for any MicroLED display, having a “spare” subpixel to use in case one of the red, green, or blue subpixels fails has the potential to increase yields. A dead subpixel will be found in the production process and any color of the subpixel that is not working will get a spray of that color. Although this fourth subpixel would increase the overall cost of this aspect of manufacturing by about 33%, the researchers estimate that it will improve yields enough to make it more than worth it.
This diagram shows the different 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 contain quantum dot material. An inkjet printer deposits said material into the bucket. As precise as this is, some “ink” spills from the right bucket (a). By turning on this subpixel, the UV light created hardens the ink in place (also a). The surface is washed to remove spilled ink (b). The process is repeated for green and blue (cf). If during this process the computer detects that one of the sub-pixels is not activated, the 4th spare sub-pixel is called into action, receiving the ink color of the dead sub-pixel (g). The final stage (h) sees the entire unit covered and secured for further fabrication and assembly.
Another potential advantage to the manufacturing process is the ability to self-cure. Some manufacturers would like to use inkjet 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 formula in the QD “ink”, a color can be deposited onto the substrate cured by its own LED as it emits UV, and then any spillover of that colored QD ink onto an adjacent subpixel can be washed away before the next subpixel receives the color si (see diagram above).
So each subpixel only has a QD for its color, even if the inkjet printer itself isn’t perfectly accurate, improving color accuracy and performance. Something about the efficiency of the pixel hardening itself makes my brain happy.
The display
The UV MicroLED prototype created by CTC is masked to look like a smartwatch. It has 300dpi.
Which brings us back to Las Vegas and that bright, small display. As you can probably tell from the images, it is designed as a smartwatch display. With a brightness of up to 1000 nits, it was quite bright in a dark room. CTC, the manufacturer and part of the Foxconn group, estimates that at full production it may be able to get 3,000 rivets.
Why, you might ask, would you need a 3,000-nit smartwatch if you’re not trying to signal a passing spaceship? To shine in your eyes. One of the big potential applications of MicroLED is for AR and VR headsets, where small, efficient displays with extremely high resolution are vital. It’s also like your TV – it doesn’t always show its maximum brightness. Having this brightness potential opens up a wider range of possibilities.
Future displays
Still in the prototype stage, the production display will be brighter and potentially used in other devices such as AR/VR headsets and more.
The question is always “When is it coming out?” This is a bit hard to answer beyond “not right now”. MicroLEDs in general and UV MicroLEDs specifically are in the early stages of development. There are MicroLED displays on the market, but it is clear that many companies want many more MicroLED displays on the market. The trend is to abandon 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 them later in the year, and certainly at CES next year.
In addition to covering audio and display technologies, Jeff gives photo tours of great museums and places around the world, incl nuclear submarines, aircraft carriers, medieval castlesepic 10,000 mile trips and more.
Also, check Budget travel for dummieshis travel book and his bestselling science fiction novel for city-sized submarines. You can follow him Instagram and YouTube.
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