Beyond OLED: What’s next for smartphone screens?

Robert Treggs / Android Authority

OLED screens have become a common sight in mid-range and even affordable smartphones over the past few years. And while not all screens are made equal, the technology has matured to the point that defects like burn-in rarely appear in the real world. With these developments, will competing display technology outpace OLED anytime soon? And if not, how will the next generation of OLED panels outperform the best of today? Let’s discuss what the future holds for smartphone screens.

Future smartphone screens: not microLED or mini-LED?

Samsung MicroLED TV

Since the first microLED screens came out in 2018, we’ve been waiting for the technology to make its way to smartphones. MicroLED displays consist of millions of micrometer-sized LEDs. Like OLED, it’s also an emission technology – each pixel can be controlled individually to achieve true black levels. MircroLED offers several advantages over current screen types, including higher brightness, higher pixel density, lower power consumption, and reduced risk of deterioration or burn-in.

It’s been four years since the technology first came out, however, and microLED displays are still far from mass production. It’s not hard to see why – the production process essentially involves moving and connecting millions of microscopic LEDs while ensuring zero defects. In the context of a smartphone, the benefits may not be worth the high cost. Perhaps that’s why Apple and other companies working on microLED displays are exploring their applications in AR/VR and wearables first.

Read moreMicroLED Explained – Next Generation Display Technology

If microLED seems too far into the future, what about mini-LED? This technology provides superior levels of contrast and brightness than any conventional LCD screen and does not burn a hole in your pocket.

Unfortunately, mini-LED displays have failed to gain market share other than the latest Macbook Pro and high-spec iPad Pro models. While some reports in 2018 indicated that we would see small LED screens on smartphones from Xiaomi and Huawei, nothing of the sort has materialized.

It is possible that the economies of scale in OLED have made it difficult for small LED screens to compete on price.

It’s possible that OLED production has matured to the point where it’s hard for smaller LED screens to compete with them in price — for smaller screens anyway. Even Apple doesn’t seem too committed to the technology, with credible rumors suggesting that the company has ordered LG’s OLED panels for future iPad models.

QD-OLED: A More Likely Filter?

Angled screens for Google Pixel 6 and Pixel 6 Pro

Eric Zeman / Android Authority

Samsung Display captured the consumer electronics industry when it unveiled its quantum dot OLED (QD-OLED) technology at CES 2022. In short, QD-OLED TVs combine the deep blacks of traditional OLED displays with the stunning color reproduction of quantum dots. This technology could open the door to screens with wider color gamuts like the Rec. 2020, peak brightness higher than traditional large OLED panels.

QD-OLED promises higher brightness and better color gamut coverage than traditional OLED displays.

However, the latest advantages of QD-OLED in the TV market do not necessarily translate to the smartphone industry. You see, the vast majority of OLED TVs on the market today use LG’s W-OLED panels — thanks to patents the company obtained from Kodak in 2009. LG’s W-OLED panels use white light and color filters to output red, green, and blue colors. Backlight filtering is a destructive process that leads to a loss of brightness and color volume. The transition to QD-OLED converts colors more efficiently, resulting in increased brightness and enhanced color reproduction.

On the other hand, Samsung’s AMOLED panels for smartphones typically use a sub-PenTile RG-BG layout, complete with red, green, and blue emitted subpixels. No filtering is required, so phone screens are actually more efficient than existing TV panels. While QD-OLED will likely offer some incremental improvements, it probably won’t be as stringent as the claims we’ve seen in the big screen market.

This does not mean that OLED panels for smartphones are perfect. PenTile displays contain twice as many green sub-pixels as red and blue. Thus, the effective decision – or what our eyes perceive – is somewhat less than what is advertised. This is an area where QD-OLED panels and their RGB sub-pixel matrix can outperform today’s smartphone displays.

RGB vs. PenTile sub-pixel . format

Pentile displays have been criticized for having a lower sub-pixel level compared to competing displays

In 2013, Samsung clarified that it switched to the PenTile sub-pixel arrangement because the green sub-pixel is the most energy-efficient. Our eyes are also more sensitive to green than red or blue, so in a PenTile display, these sub-pixels do not need to be driven by the same current to achieve equal brightness. Finally, the lower current flowing through the organic matter translates into fewer opportunities for permanent burning or color transformation.

As such, Samsung may not want to move away from PenTile-based AMOLEDs anytime soon. Nor do we know enough about the power consumption and durability characteristics of QD-OLED yet. In addition, it should be noted that blue emitters (necessary for QD-OLED) are also the most susceptible to burning compared to red and green. Samsung could use larger blue organic emitters to offset this risk, but that’s just a guess at this point.

QD-OLED looks like a promising next step for smartphone screens, but the technology is still in its infancy.

All of this is likely why Samsung Display is showing off its largest QD-OLED screens to date. We haven’t seen any indication that it also works on smartphone, tablet, or even laptop-sized screens. Moreover, reports indicate a rather low manufacturing yield for the first generation of QD-OLED panels – only about 30% without defects. This is well below the assumed 80-90% AMOLED yield, which has allowed Samsung to lower prices and increase availability for third-party smartphone manufacturers over the years.

Given the Korean manufacturer’s experience in improving manufacturing revenue, it’s likely only a matter of time before QD-OLED becomes more accessible and widespread.

Silver Linings: Annual OLED Developments

Samsung Galaxy S22 Ultra in front of bricks

Eric Zeman / Android Authority

Regardless of emerging technologies, it is worth noting that current AMOLED displays will continue to evolve as well. Samsung Display improves its manufacturing process and materials gradually every year. However, the benefits are taking a long time to reach non-flagship smartphones.

Take the Galaxy S21 Ultra from last year, for example. It was the first smartphone to feature Samsung’s updated OLED material array, unofficially dubbed the M11. According to extensive testing by Anand TechThe new OLED emitters have reduced power consumption by 25-30% compared to the previous generation.

s21 vs s20 oled emitter power consumption

Courtesy: AnandTech

Other Samsung smartphones in 2021, including the Galaxy S21 and S21 Plus, continued to use older OLED emitters – likely as a cost-saving measure. Fast forward to today, and Samsung has reportedly dropped the latest OLED emitters to the S22 Plus, but not the base S22. According to Korean industry news outlets to youHowever, lower-end Samsung smartphones in 2022 should see a slight increase in efficiency as well – moving from M8 to M9 generation emitters.

Somewhat surprisingly, Samsung’s latest release – the Galaxy S22 Ultra – did not come with the next generation of OLED emitters. Industry sources expect that to arrive later in 2022, along with the company’s upcoming foldable devices and Apple’s iPhone 14 series.

Newer OLED panel installations can greatly improve power consumption and battery life.

So what does all this mean for you and me? Better efficiency. Assuming the new SoCs don’t require more power than previous generations, we can see better battery life in the coming years. Improvements to variable refresh rate technology should help in this regard. For example, the Galaxy S22 series can only drop to 48Hz, and there’s plenty of room for a drop. We’ve seen applications as low as 10Hz in the Samsung Galaxy S22 Ultra and Oppo Find X5 Pro, and this will eventually make its way to mid-range phones as well.

Needless to say, while these improvements are important to the smartphone industry as a whole, they are especially important to the emerging foldable sector. After all, OLED is the only flexible display technology currently on the market. Somewhat disappointingly, though, if you’re hoping to make major upgrades to display resolution and color gamut, you’ll probably have to wait longer for competing technologies to mature.

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