OLED vs QLED - which is the best TV technology?

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These are halcyon days for TV technology. Ultra HD 4K is now pretty well established, HDR is beginning to make headway, and streaming puts a near-infinite supply of content at our fingerprints all day, every day.

But these are also confusing times for TV technology, with new acronyms and marketing terms raining down like confetti at the wedding of the managing director of a confetti company.

One of the key current confusions lies in the comparison between them and, as is so often the case, marketing is largely to blame. So what exactly is the difference between OLED and QLED?

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OLED pros and cons

OLED (Organic Light-Emitting Diode) is a type of display tech that involves a carbon-based film being placed between two conductors that pass a current through and cause the film to emit a light.

What’s most important is that this light can be emitted on a pixel-by-pixel basis, so a bright white or coloured pixel can appear next to one that’s black or an entirely different colour, with neither impacting the other.

This is in direct contrast to a traditional LCD TV, which relies on a separate backlight to generate light that’s then passed through a layer of pixels.

Despite many attempts over the years, no TV with a backlight has ever managed to completely eradicate the issue of light bleeding from an intentionally bright pixel to those around it.

MORE: LG C8 (2018) review

Other advantages of OLED are that the panels are lighter and thinner than a typical LCD/LED arrangement, viewing angles tend to be significantly wider, and response times can be supremely quick.

The major disadvantage is that OLEDs are very expensive to produce. Prices are beginning to get a little more realistic – thanks in no small part to LG (currently the only producer of OLED panels for TVs) selling panels to other manufacturers such as Sony, Panasonic and Philips, increasing both the amount being produced and competition in the shops – but OLED TVs still tend to be significantly more expensive than the alternatives.

For now, there isn’t an OLED TV available that’s smaller than 55in, either. OLEDs also currently struggle to reach the same peak brightness levels of the best TVs that have a dedicated backlight.

MORE: What is OLED TV? The tech, the benefits, the best OLED TVs

QLED pros and cons

The one major TV manufacturer not onboard the OLED train is Samsung, which is instead promoting a rival technology called QLED.

QLED stands for Quantum-dot Light-Emitting Diode which, in theory at least, has a great deal in common with OLED, most notably that each pixel can emit its own light, in this case thanks to quantum dots - tiny semiconductor particles only a few nanometres in size.

These quantum dots are (again, in theory) capable of giving off incredibly bright, vibrant and diverse colours – even more so than OLED.

The problem is that the quantum dots in current QLED TVs do not emit their own light. Instead they simply have the light from a backlight passed through them, in just the same way that an LCD layer does on non-QLED/LED backlit sets.

Quantum dots still improve colour vibrancy and control over LCD, but this isn’t the next-gen, game-changing technology that Samsung is suggesting with its QLED branding - it’s more a refinement of a technology the company was using in 2016.

OLED’s ability to light each pixel individually gives it a distinct advantage in that regard. While overall brightness levels are undeniably lower, contrast is still incredibly impressive.

But things get really exciting when we look forward to next-gen quantum dots, which will be capable of emitting their own light. These photoluminescent quantum dots will give the TV the ability to light up and turn off individual pixels, just like an OLED set, while theoretically retaining the advantages of greater vibrancy and brightness.

Unfortunately, it looks as though TVs that utilise these new quantum dots are still quite a long way off. Samsung’s main focus for 2018 is on improving the backlights of its QLEDs, although the company also claims its quantum dot production has been tweaked to improve their luminous efficiency by five per cent.

MORE: Samsung Q9 (2018) review

Samsung's 2018 TV line-up includes some ranges that use direct LED backlighting and others that use edge-lit. We’ve also seen two concepts that go a step further - one that uses a MicroLED panel for a backlight, and another with an LED backlight consisting of around 10,000 zones that can be lit individually.

The latter of those concepts will, according to Samsung, go into production towards the end of the year. There’d be little point in launching that model if photoluminescent quantum dots were just around the corner, so we’re going to go out on a limb and say it’ll be 2020 at least before these next-gen QLEDs appear in shops.

Arguably, the perfect TV technology would combine the brightness and vibrancy of current QLEDs with the black performance and uncompromised contrast of OLED, and current thinking is that the next-generation, genuinely light-emitting quantum dots could offer just that – to the extent that many manufacturers, including LG, are apparently working with that in mind.

MORE: What is QLED TV?

Final verdict

There’s no telling how far away those next-gen QLEDs are, though, so for now a TV buyer is forced to choose which combination of strengths and compromises best suits their taste.

Last year's TV reviews suggested the more natural and authentic images offered by OLED just about trumped the awesome punch of QLED. But with Samsung’s 2017 range generally costing significantly less than 2017’s OLEDs, there was still a compelling case for its QLED screens.

In 2018, the fight is even closer. We put the 55in LG C8 against the Samsung Q9 and it was mighty close. While the Samsung Q9FN is perhaps the more dynamic performer, particularly with HDR content, the LG C8’s balance, consistency and effortless naturalism see it take victory by a tiny margin.

And we really are talking tiny: this head-to-head is as close as these things get, despite the very different approaches of the two models. In some ways we’d have liked to have declared a tie. Ultimately we feel that the C8’s approach will suit more people more of the time. Just.

At the time of writing, the two models cost exactly the same. However, with prices fluctuating regularly in this market, any significant reduction in the Samsung's price may tip our judgment in its favour. It really is that close.

We're looking forward to seeing plenty more 2018 OLED and QLED TVs this year, so the fight is far from over...

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