Learn about QDEL, the backlightless display technology that could replace OLED in premium TVs. As OLED-equipped TVs, monitors and other gadgets slowly become more easily and cheaply available, attention is turning to what will be the next milestone in consumer display technology.
Micro-LED is often included in such discussions, but the technology is not expected to enter consumer devices until the 2030s. Display manufacturers are also toying with other futuristic ideas, such as transparent and foldable screens. But when it comes to technology that can seriously address users’ top concerns — such as image quality, price, and longevity — quantum dots seem like the way to go right now.
Quantum dots are already appearing in premium displays, especially QD-OLED TVs and monitors. The next step could be “QDEL”, i.e. “quantum dot electroluminescent”, also known as “NanoLED” screens. QDEL displays are not to be confused with the QLED (Quantum Light Emitting Diode) technology already available in TV sets and do not have a backlight. Instead, quantum dots are the light source. The expected result is displays with a wider color gamut than today’s QD-OLEDs (quantum dot OLEDs), which are brighter, more affordable and resistant to burn-in.
QDEL appears to be considered one of the most potentially influential developments in consumer displays over the next two years.
What is QDEL?
You may know QDEL as a NanoLED because that’s what Nanosys, the quantum dot supplier company developing the technology, calls it. QDEL had other names, such as QLED – before Samsung applied the abbreviation to LCD-LED TVs using quantum dots. As the listing indicates, there are still a few things to finalize about this technology.
If none of the names sound familiar, that’s probably because you can’t buy QDEL products yet. According to vendors, that could change in the next few years: Nanosys plans to commercialize it by 2026. However, this schedule seems quite ambitious considering the number of prototypes and the limitations facing QDEL.
David Hsieh, senior research director for displays at research firm Omdia, said that in terms of consumer devices, QDEL is expected to have the biggest impact on TVs, computer displays and the automotive industry. If it goes into mass production after commercialization, the cost/performance ratio may be better than that of OLED, but it would still be difficult to compete with LCD-LED on a cost basis.
Nanosys and its manufacturing partner Sharp Display describe an inkjet printing manufacturing process that can be used for QDEL monitors and televisions. The photolithography process is said to be more difficult because the quantum dots are damaged in the process, but the technology can be extended to tablets, laptops, smartphones, wearables and AR/VR products. Jeff YurekNanosys’ vice president of marketing, confirmed via email that Nanosys expects photolithography QDEL products to be the first to come to market.
The miracle without backlight
Today’s OLED screens use OLED material as a light source, and QD-OLED specifically uses quantum dots to convert light into color. In the case of QLED, the light source is a white backlight, while QDEL displays apply electricity directly to the quantum dots, which then generate light.
Pixels in QDEL displays consist of a red quantum dot subpixel, a green quantum dot subpixel and, unlike today’s QLED and QD-OLED displays, a blue quantum dot subpixel. QDEL displays use the same quantum dot cores as QD-OLED and QLED products, said Nanosys’ Yurek, adding, “The outer layer functionalization of the quantum dots must be changed to make them compatible with each display architecture, but the cores doing heavy work are pretty much the same on all of them’.
Because QDEL pixels generate their own light and can therefore be turned off completely, displays can deliver the same deep blacks and rich contrast that made OLED popular. However, by using direct-view quantum dots, stakeholders say a wider color gamut is possible than what we’ve seen in consumer displays. Due to fewer layers and components, the pricing, longevity and even thinness of QDEL products will be more favorable.
QDEL in operation
You can’t currently buy a product with a QDEL screen, but companies have shown off prototypes over the past few years. The latest update on the anticipated technology came at CES in January, when Sharp Display showed off two prototypes to a small group of attendees. One screen was 12.3 inches and had a resolution of 1920×720. The other prototype marked the first time we saw QDEL scaled to a size suitable for products such as monitors. However, the resolution of the 30-inch prototype is unknown.
One of the biggest improvements of the current prototypes compared to the previously presented ones is that they were made at atmospheric pressure, rather than in a vacuum chamber. As CNET reported, this is “a big step toward cost-effective manufacturing.”
Advantages of QDEL
The fact that quantum dots are already successfully applied to LCD-LED and OLED screens is encouraging for future QDEL products. QDEL stakeholders claim that the technology can provide efficiency benefits such as lower power consumption and higher brightness compared to OLED. During research with a prototype device, the quantum dot light-emitting diodes achieved a value of 614 thousand nits – of course, these are not results that should be expected in a real consumer product.
Because of these expected benefits, some display enthusiasts predict that QDEL will one day replace OLED and other premium display panel technologies in high-end consumer devices.
They also hope that QDEL can last longer than OLED over time, especially since the former technology does not rely on organic materials that can cause burn-in. Currently, however, researchers are still working to make the blue and green quantum dot materials long enough to make viable consumer devices without the use of cadmium. As it stands, QDEL displays would become noticeably dimmer and faster than today’s OLED displays.
However, optimists believe that the lifetime of QDEL displays may one day match that of LCD-LED screens and outlive OLEDs. Nanosys believes that blue quantum dot materials can be developed to last longer than blue OLEDs because blue OLEDs require high efficiency and long life at “the right wavelength or color,” Yurek explained. He added, “short-wavelength light like blue is high-energy… The energy required to produce the deep, short-wavelength blue color required by video standards like DCI-P3 is high enough to damage the material used to produce the light. This is one of the main reasons why blue OLEDs have a shorter lifespan than other colors.”
Still, the lifetime of the quantum dot’s emissive layer is perhaps the biggest bottleneck to commercializing the technology, Hsieh added. Yurek said that related developments are expected to be announced at the SID Display Week conference in May.
What about Micro LEDs?
Micro LED has many of the advantages of OLED, including individually emitting pixels that provide theoretically infinite contrast. Like QDEL, Micro LED cannot be as susceptible to burn-in as OLED and can be brighter than OLED.
Micro LED is here today, but for now it’s terribly expensive. However, scaling the technology down to a reliable and affordable size to standard TV sizes puts it out of reach for most due to manufacturing challenges. According to Yurek, QDEL will eventually be cheaper to manufacture than Micro LED, just like OLED and LCD-LED. But until we see this in practice, we have to accept it a bit.
QDEL can reportedly be manufactured using the same machinery and equipment currently used to manufacture LED displays. Furthermore, although QDEL and Micro LED are both based on crystalline inorganic semiconductor materials, these materials are processed differently in the manufacture of QDEL and Micro LED displays, and the latter present different challenges.
We don’t yet know what the image quality will be like in actual QDEL products, and how much tech brands will eventually invest in its implementation. Some believe that QDEL may have an immediate impact than Micro LED, as Micro LED has been delayed in mainstream product adoption. In March, for example Mark Gurman citing anonymous sources, he wrote in Bloomberg that it is Apple has given up on making the Apple Watch and potentially other gadgets with Micro LEDs due to cost and complexity. All this happened after years and billions were invested in the development. According to Gurman’s report, Apple will continue to rely on OLED for smartwatches and may be looking for new partners to go down the Micro LED route again.
In contrast, however, the Samsung in September it reiterated its focus on Micro LED as the future of premium TVs.
Availability of QDEL
“In our public roadmaps for the materials, we set a target of 2026 for commercial readiness. When consumers get access to the technology depends on the brands and the specific products they want to introduce,” said Yurek.
That’s encouraging, but doesn’t give a firm timeline for when QDEL TVs will be available for purchase, and I wouldn’t be surprised if the commercial availability date is pushed back. Even if Nanosys were ready to sell it to other brands, many other pieces would have to fall into place before people could buy a product with direct-view quantum dots. And early products may not live up to expectations, as is sometimes the case with emerging technologies.
So what comes after OLED? There are many ideas – including more and better OLEDs. But the jury, which includes researchers and commercial R&D companies, technology brands and ultimately users, is still out. And it will take years before a decision is made.
While we wait, those interested in exceptional image quality at a more affordable price can easily turn to QDEL.
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