Once upon a time there were CRTs. Then came plasma and LCD. Most recently we got OLED. Each of these technological advances improved picture quality in some ways and kept others the same. Each had their weaknesses, but the overall development was for the better.
A few years ago, quantum dots entered the scene, expanding the available technologies. These microscopic particles boosted the performance of LEDs, LCDs and OLEDs, making them brighter and more colorful. However, these points of light do not create the image. The image is created by LCD or OLED pixels that are directly or indirectly enhanced by quantum dots.
Although quantum dots were a big step in performance, they were still limited by the older technologies around them. The main drawbacks inherent in LCD and OLED were still there. The next step, the “holy grail” of quantum dots, was direct-view quantum dots, also known as nanoLEDs. These would be displays that use only quantum dots – no LCD or OLED – and theoretically offer even better picture quality with little or none of the drawbacks of previous technologies. It seems that future technology is almost a part of our present. This is why nanoLED is potentially so great.
It will help to explain quantum dots first. We have written about them much in the past, but the short version is that they are little particles that glow when you hit them with energy. This energy for the past few years has been light. Typically, blue light is created by an LED or OLED, and this blue light excites red and green quantum dots. Together, they create all the light you need to create an image.
They are called photoluminescent quantum dots. “Photo” as light and “luminescent” as “luminous”. The most common use of quantum dots is as a layer in the sandwich that makes up a modern television. This “color conversion layer” can be combined with other layers, but for our purposes you can just think of it as a thin layer of yellowish-looking plastic that helps a TV or other display produce a lot of color.
Because quantum dots have near-perfect efficiency, they can improve brightness or reduce a TV’s power consumption without any other changes. Compare this to the most common way to create color on older LCD displays: color filters. Basically, a color filter would block every “color” of light except red, green, or blue. All the other colors were still created by the white backlight, which meant that a lot of light was wasted, being blocked by the color filter. Or to put it another way, for every red pixel the TV was still creating green, blue, and everything in between. You were just seeing red; the rest was a waste of energy.
By switching to quantum dots instead of traditional color filters, almost all of the energy used by the TV to create light is sent to your eyeballs (essentially). Typically, a blue LED or OLED produces nothing but blue light. This is the blue you see with the blue pixels. Quantum dots convert blue almost perfectly into red and green. Basically, nothing is lost, so the TV can be more efficient. That means a brighter TV that uses less power, and often both. This is a big reason why TVs are capable of such impressive light outputs and wide colors these days.
So far, quantum dots have been Robin to OLED and Batman to LCD. They helped but weren’t the star of the show. What’s different about nanoLEDs is how the quantum dots create light. Instead of being photoluminescent, these direct quantum dots are electroluminescent. Electro, as in electricity. Snap a pixel, which is just a fraction of a volt quantum dot, and it lights up. Put enough of these pixels close together, program a way to access each one, and you have a display.
Nanosys, one of the main quantum dot manufacturers, has been working on this technology for years. A few months ago I saw a prototype in person, and a little later I got a behind-the-scenes look at their factory where they make quantum dots. (It looks like a microbrewery.) Nanosys calls the electroluminescent quantum dots “nanoLEDs,” though they’re also called EL-QDs and QD-LEDs.
Interestingly and surprisingly, according to Nanosys, there is not a huge difference in the overall composition of photo- and electroluminescent quantum dots. They’re not exactly interchangeable, but they’re more similar than not. The difficulty is largely not in the quantum dots themselves, but in everything around them. Delivering the right amount of electricity at the right time to allow a bunch of quantum dots to look like your favorite TV show is the challenge. Many companies are currently experimenting with different production methods, including inkjet printing and photolithography. Both methods have potential upsides and downsides, but for convenience they are similar to how modern displays are currently made. It’s less about inventing a new wheel than figuring out how to make current wheels fit a new car.
Pros and cons of quantum potential
No technology is perfect, which is doubly true for new technologies. Since there are no publicly visible and certainly no commercial nanoLED displays, we have to make some educated guesses about what these new displays might look like.
- Contrast: Since every pixel can be disabled, we can expect contrast ratios similar to or better than OLED.
Even thinner displays: With fewer layers needed to create an image, TVs and other displays can be even thinner. This could mean slimmer TVs, thinner phones, lighter VR headsets, and more.
For print: In theory, inkjet and other manufacturing techniques could create nanoLEDs on almost any flat or curved surface, inexpensively.
color: Similar or even better color than that currently found in QD-enhanced LCD and OLED displays.
Scalable: Using technology similar to how LCDs are made, nanoLED displays could theoretically be available in the same range of sizes and resolutions as LCD displays. So everything from smartwatches to wall mounted TV.
Price: This is new technology, so the first few generations are likely to be expensive.
Resistance: There is a lot of money invested in LCD and OLED manufacturing. Companies that want a return on the money spent on these factories and do not want to spend more money to convert them, and this could slow down the widespread use of nanoLEDs.
Productivity: In theory, they will offer incredible contrast ratios, but will nanoLED be as bright as QD-enhanced LEDs and OLEDs?
“Theoretically:” The inkjet and photolithographic nanoLED fabrication methods that will unlock its potential have yet to be proven at scale.
Lifespan and reliability: NanoLEDs most likely won’t have the potential burn-in problems of OLEDs, and current red nanoLEDs have the potential to last longer than LED LCDs. Green and blue nano-LEDs do not yet have such longevity, but this is a key focus of the research.
I saw my first nanoLED display at CES 2023, but I had heard Nanosys talk about the technology for years. It also seemed like the logical next step when I first learned about quantum dots. It was always “in a few years” though. However, Nanosys’ quantum dot chronology from almost a decade ago matches up surprisingly well with the particles’ actual use in televisions. So when the company says “several years,” I’d be surprised if that wasn’t close. The manufacturer expects to see it used first in smaller displays, such as phones and tablets, and then in larger displays such as monitors and televisions.
Nanosys isn’t the only company working on nanoLEDs. A number of companies, including BOE, Samsung Display, Sharp and TCL, are experimenting with this quantum dot technology. These are some of the most successful players in the world of display manufacturing, and the fact that they’ve all made working prototypes and are all interested in the technology is reason enough for us all to be curious about it.
However, it will certainly be a while before you can choose between a QD-OLED and a nanoLED display at your local Best Buy. At this point, I’d bet that quantum dot LED LCDs will be pushed to the mid and low end of the market. Although maybe some mini-LED can be held there (which, by the way, can also use quantum dots). Regardless, it’s a future filled with plenty of great-looking TVs.
In addition to covering TV and other display technology, Jeff takes photo tours of cool museums and locations around the world, including nuclear submarines, massive aircraft carriers, medieval castles, epic 10,000 mile road trips and more. Check out Tech Treks for all its tours and adventures.
He wrote a bestselling science fiction novel for city-sized submarines and a continuation. You can follow his adventures on Instagram and his YouTube channel.