OLED vs LED LCD – An in-depth guide to the rival technologies
2017 is shaping up to be a big year for TV tech. Ultra HD, or 4K, continues to be adopted as the standard resolution in the AV world. High dynamic range (HDR) is no longer the next big thing that's coming soon – it's here now.
The same can be said of smartphone screens, which continue to reach dazzling levels of sharpness thanks to increased resolutions and better pixel-per-inch densities.
But for all the new features coming our way, it's worth taking a minute to consider an old battle going on between two display types. These two, broad kinds of display can be found across monitors, TVs, mobile phones, cameras and pretty much everything else with a screen.
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In one corner is LCD (liquid crystal display). It is by far the most common type of display in all kinds of tech. If you see a TV described as ‘LED’, it's actually an LCD display, albeit one that uses LEDs as its lighting source.
Then there's OLED (organic LED), which is used in high-end phones like the Samsung Galaxy S7 and high-end TVs like the Sony A1. That's a completely different technology. Some people say OLED is the future, but is it really that much better than a good LED LCD display? We’re going to look into how these display techs differ, what they’re good for, and how they work.
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How are they different?
In a nutshell: LED LCD displays use a backlight to illuminate their pixels, while OLED’s pixels actually produce their own light.
You might hear OLED’s pixels called ‘emissive’, while LED LCD tech is 'transmissive'. The brightness of an OLED display can be controlled on a pixel-by-pixel basis. This sort of dexterity just isn’t possible with an LED LCD.
In cheaper TVs and LCD-screen phones, LED LCD screens tend to use 'edge lighting', where LEDs actually sit to the side of the display, not right behind it. The light from these LEDs is then fired through a matrix that feeds it through the red green and blue pixels and into our eyes.
OLED vs LED LCD: Contrast
That brings us to our first calling point: contrast.
With LED LCD screens, control over the level of brightness across the display is limited. Take an LCD display into a darkened room and you’ll notice that parts of a purely black image aren’t actually black, because you can still see the backlighting (or edge lighting) showing through.
Being able to see unwanted backlighting affects a TV's contrast, which is the difference between its brightest highlights and its darkest shadows. You’ll often see a contrast ratio quoted, particularly in TVs and monitors. This tells you how much brighter a display’s whites are compared to its blacks. A decent LCD screen might have a contrast ratio of 1,000:1, which means the whites are a thousand times brighter than the blacks.
Sony's demo of LCD vs OLED contrast
Contrast on an OLED display is way higher. When an OLED screen goes black, its pixels actually produce no light whatsoever. You can't get darker than that. That means you get an infinite contrast ratio, although how great it looks will depend on how bright the LEDs can go when they're lit up.
To compensate, many LED LCD TVs offer a "dynamic" contrast mode, which has the TV altering the backlight level according to the image on screen. It's not the best solution for movies, because there the variance in screen brightness is much less predictable.
The best LED LCD TVs are called direct LED displays. Here, the LEDs sit right behind the LCD panel rather than to the side of it, giving a screen greater control over how bright certain areas of a screen are. You’ll find this tech in some higher-end TVs. However, its effectiveness varies.
Unlike OLED, Direct LED-lit TVs still don’t have pixel-level control over light levels. Instead, a display has ‘zones’ or groups of LEDs than can be dimmed. It can be extremely useful for doing things like blacking-out the bars you see when watching a 21:9 cinema aspect movie on a 16:9 TV, but generally isn’t as good at dealing with more complicated tasks.
Panasonic's TX-65DX900 uses 'honeycomb' backlight tech which helps LCD compete with OLED's contrast capabilities
For example, looking at a brightly-lit face on top of a completely black background, you might see a halo of light around parts of the face because the backlight zones didn’t quite match up with what’s on screen.
Of course, TV makers are getting better at this every year. Panasonic's DX900 series TV uses a 'honeycomb' backlight structure, which divides the LED backlights into hundreds of individually controllable zones, with rigid dividing structures limiting light leakage and helping to reduce 'halo' effects.
Can LCD match OLED?
In terms of overall performance, both OLED and LCD are capable of reproducing fantastic picture quality. The big TV feature of 2017 is High Dynamic Range (HDR). This is shorthand for a number of improvements that allow for the retention of detail in darker parts of the image, better colour reproduction, deeper blacks and brighter whites. Basically, a wider range for colour and contrast.
In order to establish a set of standards which a TV must be able to hit in order to be considered HDR Ready, a new 'Ultra HD Premium' label has been introduced. You can read more about this in our detailed guide, but for our purposes, it's worth noting that both LCD and OLED TVs have been awarded the UHD Premium label. That means that both display technologies are capable of producing cutting edge picture quality, despite their various differences. The battle is therefore far from over.
So which is better? The answer actually depends on your personal tastes. Let's go into the key differences to see why you might prefer one over the other.
LED LCD TVs can never match OLED in black levels. No amount of dynamic contrast tinkering and local dimming in an LCD TV can match the actual absence of light offered by OLED. Then again, LCD TVs are generally much brighter, reaching around 2000 nits – the equivalent of 2,000 fictional candles. The best OLED TVs can get up to about 800 nits right now.
Much of this depends on where you watch TV. If you favour dark rooms, you might prefer OLED. In the TV space, that has become all the more important now that plasma TVs have bitten the dust. Plasma displays used to be the go-to technology to get better contrast than LCDs, but ultimately they were too expensive to make and to buy.
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Where are all the OLEDs?
So if OLED is so good, where are all the OLED TVs?
It turns out they are extremely difficult to produce, which made them seriously expensive to begin with. Samsung only made one OLED model, the KE55S9C, and it sold for £7,000 in 2013. LG's EA9800 cost around the same, and neither of those were 4K TVs.
Since then, the two companies have gone in opposite directions: Samsung's TV division abandoned the OLED game while LG doubled down and threw money at the technology. In 2015, LG pumped over $600m into production sites.
It was a risky move, but LG's investments have paid off. OLED is now better than ever, and prices have come right down. We're still not looking at the bargain basement prices of some LCD TVs, so you can forget about OLED in your spare bedroom. But now you can find a 55-inch OLED TV for under £1,800, which is in line with some of the premium LCD rivals.
The OLED momentum is strong. At CES 2017, LG announced that it had 10 models of OLED TV, all of them 4K and HDR compatible. And LG's OLED panels are now good enough that other manufacturers are buying them: Panasonic, Sony and Philips are taking tentative steps into the OLED pool, all using LG's panels.
Samsung is resolutely sticking to LCD, however. The company has had immense success with its LCD TVs, and much of that is down to the fact that it is able to offer high-end tech for less money than its OLED rivals.
Lower cost is one of the main benefits of LCD displays, across all fields. You’ll find high-quality LCD screens in devices that cost (relatively-speaking) peanuts, such as the IPS panel of the Motorola Moto E, a phone that costs well under £100, if you shop around.
The lower cost of LCD is also what has made 4K TVs so affordable so quickly. You can buy a decent 4K TV for around £500 these days, but at this price range you're guaranteed to find LCD. Will OLED ever get this cheap? Probably, but not any time soon.
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OLED vs LED LCD: Viewing Angles
OLED enjoys excellent viewing angles, primarily because the technology is so thin and the pixels are so close to the surface. That means you can walk around an OLED TV, or spread out in different spots in your living room, and you won't lose out on contrast.
Viewing angles are generally worse in LCDs, but this does vary hugely depending on the display technology used. And there are lots of different kinds of LCD panel.
Perhaps the most basic is twisted nematic (TN). This is the kind used in budget computer monitors, cheaper laptops and some very low-cost phones. It offers very poor angled viewing. If you’ve ever noticed that your computer screen looks all shadowy from the wrong angle it’s because it has a twisted nematic panel.
Thankfully a lot of LCD devices use IPS panels these days. This stands for 'in-plane switching' and it generally provides much better colour performance and dramatically improved angled viewing.
IPS is used in the vast majority of smartphones and tablets, plenty of computer monitors and lots of TVs. It’s important to note that IPS and LED LCD aren’t mutually exclusive, it’s just another bit of jargon to tack on. Beware of the marketing blurb and head straight to the spec sheet.
OLED vs LED LCD: Colour
The latest LCD screens can produce fantastic natural-looking colours. However, just as with the viewing angle, it depends on the specific technology used.
IPS and VA (vertical alignment) screens can provide great colour accuracy when properly calibrated — the iPhone 6S is a great example of a phone with top colour accuracy — but TN screens can often look weak or washed-out.
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OLED's colours have no issues with pop and vibrancy, but early OLED TVs and phones had an issue reining the colours in and keeping them realistic. These days, it's a lot better – Panasonic's latest OLED TV is even suitable for use in Hollywood colour grading studios.
Where OLED struggles is in the matter of colour volume. That is, really bright scenes may challenge an OLED panel's ability to maintain its colour saturation levels. It's a weakness that LCD-favouring manufacturers enjoy pointing out.
What is the future for LCD and OLED ?
Display makers are doing their best to tweak and improve the various limitations of LCD. While OLED’s job over the next few years is to become cheaper and brighter, we’re seeing more distinct developments in LCD town.
Perhaps the most catchy is the quantum dot. It is a new way to approach the LCD’s backlight. Rather than using white LEDs, a quantum dot screen uses blue LEDs and "nanocrystals" of various sizes, which convert the light into different colours by altering its wavelength.
Samsung has been rocking Quantum Dot tech for a few years now, and their latest development actually puts LCD a lot closer to OLED performance. They've wrapped their nanocrystals in a metallic alloy and rejigged the lighting system, which fixes much of the contrast and viewing angle issues associated with LCD panels.
So, who wins?
That's a tough one. In terms of sheer numbers, LCD is definitely winning. It's been around for much longer and it's cheaper to make, which gives it a major head start in market saturation.
If you're dealing with a limited budget, whether you're buying a phone, a monitor, a laptop or a TV, you'll almost certainly end up with an LCD-based screen. OLED, meanwhile, remains a more luxury proposition.
But LCD's dominance is slowly being chipped away. OLED tech is gaining momentum. Already it's taken over the best phones, and OLED is making big waves in the TV world.
Which is better? Even if you take money out of the equation, it really comes down to personal taste. Neither OLED nor LCD LED is perfect. Some would extol OLED's skill in handling darkness, and its lighting precision. Others would prefer LCD's ability to go brighter, and maintain colours at bright levels.
How do you decide? Stop reading this and go to a shop to check it out for yourself. A shop floor isn't the best indication of ultimate picture quality, but it will give you a good idea of what your priorities are. Whether you ultimately side with LCD or OLED, you can take comfort in the fact that both technologies have matured massively, making this a relatively safe time to invest.