OLED vs LED LCD – An in-depth guide to the rival technologies
2016 is shaping up to be a big year for Screen tech. As 4K continues to be adopted as the standard resolution in the AV world, new features such as HDR look set to make a big impact as TVs get clearer, brighter, sharper, and generally better.
The same can be said of phone screens, which continue to reach dazzling levels of sharpness thanks to increased resolutions and better pixel-per-inch densities.
But as we prepare for all the new features coming our way, there's 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.
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In one corner sits LCD, 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 with a backlight that's made of LEDs rather than another kind of light source.
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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In a nutshell, how are they different?
To distil the differences between these technologies into the most concise little nugget, 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’.
What this means is that the brightness of an OLED display can be controlled pixel-by-pixel. This sort of control just isn’t possible with an LED LCD.
In cheaper TVs and LCD-screen phones (that’ll be most of them), LED LCD screens use LED backlights that 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.
So 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 an image aren’t perfectly black, because you can still see the backlight showing through.
This is also a good time to explain contrast. Particularly in TVs and monitors, you’ll often see a contrast ratio quoted. This tells you how much brighter a display’s whites are compared to its blacks, and a decent LCD screen might have a contrast ratio of 1,000:1.
The whites are a thousand times brighter than the blacks.
Sony's demo of LCD vs OLED contrast
OLED vs LED LCD: OLED Contrast
In an OLED display, as a pure black screen should not emit any light at all, you get an infinite contrast ratio. No matter how many times you multiply nothing, you end up with zilch.
When you see a ‘dynamic’ contrast ratio figure, which will likely be much higher, that refers to an LCD TV's ability to alter the backlight level depending on the image on screen. It’s not really a good indication of the sort of contrast you’ll see in, say, movies because there the variance in screen brightness is much less predictable. You can't dim the backlight when another part of the screen needs a good level of luminance.
Trying too hard to alter backlight levels to suit can also cause obvious and jarring ligh level changes too.
There are LED LCD displays that have a good crack at replicating the sort of contrast you get with OLED, though, 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, how effective this technology is varies.
Direct LED-lit TVs still don’t have pixel-level control over light levels like OLED. 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, if there was an image of someone’s 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. If you’ve read some of our TV reviews, you may have heard our TV expert John Archer talk about this sort of halo’ing.
Of course, TV makers are getting better at this every year. Panasonic used CES 2016 to debut a new 'honeycomb' backlight structure which divides the LED backlights into hundreds of individually controllable zones with rigid dividing structures between each zone to limit light leakage and help reduce the 'halo' effect. The new tech can be found on the TX-65DX900.
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 2016 looks likely to be 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.
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 what are some of the key differences? We had a chat with professional ISF television calibrator Vincent Teoh who told us, “LED LCDs will never match OLED in black level,” but also says that LCD “already surpasses [OLED] in peak brightness.”
For watching content in dark rooms, an OLED display is therefore the best solution you can currently get. In the TV space, that has become all the more important now that plasma TVs are not made any more. Plasma displays used to be the go-to technology to get better contrast than LCDs, but every company that used to make such sets ceased after people, well, stopped buying them.
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The Samsung Galaxy S7 uses OLED technology
OLED displays are great for screen enthusiasts, and not just in TVs. The Samsung Galaxy S7 and Galaxy S7 Edge both use OLED and probably have the best phone screens ever made.
Samsung is the main supporter of OLED phones. While Nokia Lumia and Motorola have occasionally used OLED screens, Sony, Apple and LG all predominantly use LCD-type displays in their phones.
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. Only three companies to date have released full-size, commercially-available TVs: Samsung, LG, and Panasonic. However, 2016 should see more companies getting on board with OLED, including Philips. The company is reportedly working on a OLED TVs which could see a 2016 release.
Samsung’s OLED was called the KE55S9C, and it originally sold for £7,000. For that price you’d expect perfection, but there was a concern about the blue LEDs used in the set — they last for less time than the green and red ones. It’s still enough for years of operation, but given the price it was a worry.
LG gets over this issue in its OLED TVs by using white LEDs, and colour filters over the top of them. It’s a little more LCD-like in this respect.
The company is doing great work in trying to make OLED TVs more mainstream, and while there’s a way to go before OLED models are anywhere close to the sort of prices non-enthusiasts can afford, LG is ploughing away where other TV makers steer clear.
The cheapest OLED available right now is the non-4K LG 55EC930V for around the £1,299 mark. It's a decent TV but it's also fairly outdated now, and without 4K it's going to become insignificant fairly soon, if it hasn't already. All of which means you're still looking at paying more than £2,000 for a 4K OLED TV.
When it comes to LCD, you can get a 4K set for well under £500 now, while the cheapest 4K OLED is the 55-inch, £2,499 LG 55EG960V. Still, that's a significant drop in price from a year ago when the cheapest 4K OLED was the £6,500 LG 65EC970V.
That all makes sense considering what LG Product & Range Planning Manager Robert Taylor told us last year: “2015 will be a key year for OLED TV as we will really demonstrate our commitment to OLED technology by investing over $600m into production sites across the world that will take production to 1m units.
“The benefits of this extra production will result in greater economies of scale which will enable us to produce not only a wider array and range of OLED TV products but also in greater volume, resulting in better cost prices and reduced production costs. With these savings we will be able to make OLED TV’s more effectively and even look to create more entry level models.”
So while OLED TVs are still fairly pricy, continued investment in the technology, particularly from LG, has led to dramatic drops in prices. By the end of 2016 we may start seeing affordable 4K OLED TVs start creeping onto the market.
What are the benefits of LCD?
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.
LCD screens can often look sharper than OLED displays of the same resolution too. It’s all down to the tactics display producers use to deal with OLED’s quirks.
Samsung unveiled a range of new LCD TVs at CES 2016
The problem is that not only do different colour LEDs have different lifespans, they also have different levels of light output. So while LCD screens can use incredibly regular patterns of red, green and blue sub-pixels, OLED displays generally have to be a bit more… dynamic.
For example, in the Galaxy Note 4, instead of having pixels with three regular sub-pixels, there are red-green-blue-green little dots that effectively form two pixels. They’re not the same shape either: the reds and blues and diamond-shaped while the greens are smaller ovals.
This is called a PenTile arrangement, and makes less pixel-packed OLED displays look a bit fizzy. The effect has largely disappeared in recent phones thanks to the sheer resolution on offer, and LG’s OLED TVs do not need to use such techniques as they use a colour filter rather than coloured LEDs.
But OLEDs just aren't as easy to work with as LCDs it seems.
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Samsung's OLED TV
OLED vs LED LCD: Viewing Angle
OLED displays tend to have near-perfect viewing angles, although they will often take on a slightly different hue when viewed from an angle. The Galaxy Note 4, for example, goes a bit blue-ish.
In LCDs, viewing angles 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. Display tech engineers sure seem to have a thing for acronyms.
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 — but TN screens can often look weak or washed-out.
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OLED screens have even greater colour potential than the best LCDs, but the problem here is reining them in. These screens are capable of reproducing more of the natural colour spectrum than is actually covered by the standards used in film and software production, but that means if they’re not properly calibrated colours can look overcooked.
You’ll see this quite commonly in OLED phones, but OLED TVs — being enthusiast products — tend to have fantastic colour reproduction.
What is the future for LCD and OLED ?
Display makers are doing their best to tweak and improve the various limitations of LCD, though. While OLED’s job over the next few years is to become more affordable and just get out there a bit more, 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 these ‘quantum dots’ of various sizes, which convert the light into different colours by altering its wavelength.
Our TV calibrator buddy Vincent Teoh had a few words to say on quantum dots too:
“It's not a stop gap – it's crucial to help LED LCD achieve a wide enough colour gamut to satisfy current UHD standards. For normal HD stuff, most consumers probably won't appreciate (or care) about quantum dot vs non-quantum dot displays.”
The Kindle HDX was the first quantum dot tablet
Some of Amazon’s Kindle Fire HD tablets already use quantum dot tech and at CES 2016, Samsung revealed an exciting new flagship range of SUHD TV sets, all of which use the trendy nano particles. Quantum dots are one of the main ways in which LCD displays are able to reach the UHD Premium standards and fulfill HDR requirements.
While LCD is never going to match OLED for black level and contrast, any limits to colour reproduction are being whittled away.
Whether you side with LCD or OLED, the future is certainly going to be interesting.
So, who wins?
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. Most likely an LED LCD one too (the other common type is ccfl).
For manufacturers, it's a pretty easy tech to deal with, not least because it has been the default technology for aeons. It's also a more problematic technology in terms of image quality, next to OLED at least, but little 'sub technologies' like IPS have come in to help with that over the years.
These little optimisations are things OLED lacks at present: Super AMOLED is largely just an OLED that merges a touchscreen layer with the display element. Making OLEDs is tricky, and that is reflected in the price. But across phones and TVs, they do get you some of the most eye-popping imags available and with continued investment from companies such as LG, OLED certainly isn't going away any time soon.
Thanks to Vincent Teoh with his help on this article. You can read more about his calibration services on his site.