OLED, QLED, IPS, VA, Micro-LED, backlighting, contrast, viewing angles, colour rendering, refresh rate... It is difficult to find your way b...
OLED, QLED, IPS, VA, Micro-LED, backlighting, contrast, viewing angles, colour rendering, refresh rate... It is difficult to find your way between all types of screens and their characteristics. This sector is a real headache for the uninitiated, and even technology enthusiasts can sometimes get lost in it. So let's see what the indicators put forward by the manufacturers and the differences between the different types correspond to.
TN, VA, IPS, OLED, LCD, Micro-LED, QLED, Mini-LED... When it comes to screens, the technologies used on our devices today are very numerous. If on our smartphones, the choice is still limited, the number of references for PC monitors and televisions is quite dantesque. So it's easy to get lost and not understand the distinctions between the different standards used in the industry. This is unfortunate since you can't choose the perfect type of screen for your needs and budget because of this lack of knowledge. In this post, we will try to help you see more clearly and finally remove the vagueness on what is really behind all these acronyms.
On a smartphone, an LCD screen is necessarily an IPS screen. This technology has definitively supplanted TN screens on our mobiles. But there are many other types of LCDs, which we detail below and which are used for example on PC monitors and TVs.
But before we start, a few words about LCDs in general. LCD stands for Liquid Crystal Screen. The beginnings of the technology date back to the 1970s, but it wasn't until the mid-1980s that serious advances were made. LCD was finally introduced in commercial devices to the general public at the end of the 1990s, and enjoyed a boom at the beginning of the century with the democratization of flat screen screens.
LCDs exploit the polarization of light for screen purposes. This means that they play on transparency, but do not emit light directly. This is why they must be equipped with a backlighting device.
Screens based on Twisted Nematic (TN) technology were the first LCDs to appear on the market and continue to exist on the market today, with many developments and improvements. Picture quality is not its strong point, with lower colour rendering and contrast than found on other types of LCDs. The viewing angles are also far below average. This is why TN is not suitable for a television set. For a computer monitor, make sure that the screen will be at the right height and in line before making a purchase. Avoid the TN for a multi-screen setup.
If the TN still exists in 2020, it is because it still offers significant advantages over other available technologies. First of all, its price: TN screens are among the cheapest on the market. You can buy 27-inch TN at the same price as a 22-inch VA or IPS. These screens are also extremely fast for LCD. Even on entry-level models, they can offer very low response times of less than 5 ms. TN screens also offer a high refresh rate (120, 144 or 240 Hz) at a contained price.
VA (Vertical Alignment) technology has been upgraded many times since its inception. As a result, it is available in several versions, some of which are still in use today. These include MVA (Multi-domain Vertical Alignment) and PVA (Patterned Vertical Alignment) technologies, which have improved black depth and contrast compared to previous VA screens. The best of these two criteria is PVA, designed by Samsung. On the other hand, it is more often the object of swarming in the image.
In general, VA screens are popular because they block the passage of backlight light more easily than other types of LCD screens. This results in the best contrast and black quality on LCDs. But this technology also has its weaknesses. The viewing angles are narrower than on IPS, so it is not the best solution for a TV, whereas VA is much more acceptable for a PC screen. The other drawback is the slowness of these screens (especially MVA), which does not make it a good solution for gamers looking for performance.
Note that Sharp has introduced a new range of VA screens with UV²A. It offers correct viewing angles (but still not at IPS), retains the benefits of VA in terms of contrast and is faster than MVA and PVA. It is the best Vertical Alignment solution of the moment, but it has not been democratized on consumer products so far. Sharp believes that it is too expensive to be really profitable and that a consumer who wants to put the price tag on a screeen should instead turn to OLED.
If you've heard of a screen technology, this is probably it. IPS (In-Plane Switching) has become very popular with manufacturers for its value for money and balanced features. One of the features of this standard is its very wide viewing angles. This makes IPS a very good solution for TV sets, which are rarely viewed directly in front, either horizontally or vertically. The same goes for smartphones: IPS provides good picture quality even if the mobile is at an angle, on the table, or in any other situation where it is not right in front of the eyes.
The IPS is also shimmering colours worthy of VA screens. The weak point of the technology lies in the contrasts, which are not very convincing. Black is more of a very dark grey than real black. You may have noticed the difference between blacks screened by an IPS screen and those screened by an OLED screen on a TV or smartphone.
IPS screens also have better speed than those offered by VA screens. Many low-cost IPS screens can reach 75 Hz. However, the price tends to skyrocket for consumers looking for IPS with a higher refresh rate (120, 144 or 240 Hz). A 120 Hz IPS screen will thus very often be more expensive than a 120 Hz TN screen, the former combining performance and screen quality.
Be careful here, many users tend to get confused. The QLED (Quantum-dot Light Emitting Diode) is exclusively used by Samsung, which used marketing strategies to impose in the minds of users that the QLED would be "Samsung's OLED". In reality, the QLED works today thanks to a LED backlighting technique, just like any other LCD screen. It is therefore part of this family of screens. The OLED, with its pixels that emit their own light, has nothing to do with the QLED.
This being said, the QLED remains very interesting, whatever LCD it is. The promise of this quantum box filter technology: bright and faithful colours, rich detail, high contrast and a luminance that can potentially reach up to 4000 nits. The QLED is capable of screening 100% of the colour space of the DCI-P3 standard used for digital cinema and allows deeper blacks to be enjoyed than with other LCD technologies.
The QLED finally refers mainly to an optimized backlighting technique. QLED televisions actually use a VA screen, which they improve, but also take up some of its weaknesses. For example, the speed and viewing angles offered by the QLED are not perfect, even though they are better than on a conventional VA screen. However, the QLED does have a lower-than-average power consumption.
Samsung's discourse on its QLED technology is as follows. According to the South Korean manufacturer, the QLED has a much better lifetime than OLED, whose organic components are irretrievably degraded. An argument that is difficult to verify for several reasons. First of all, we do not yet have enough hindsight on these two relatively recent technologies to properly judge the lifespan they provide. Second, OLED is evolving and while early OLED TVs could suffer from long-term problems, manufacturers have adapted and incorporated features to address this concern.
The second argument put forward by Samsung is that while OLED offers a fabulous experience in dark environments, it loses interest when there is light, as is often the case in our living rooms. In this case, the luminance of the QLEDs takes an advantage. Especially since, according to the group's discourse, OLEDs quickly lose colour and brightness over time (again, this is less and less true). For Samsung, the interest of OLED is mainly justified for small format screens. In fact, it uses its AMOLED technology on its mid- and high-end smartphones.
Finally, be aware that the technology behind QLED is not only used by Samsung. The equivalent on the Sony Bravia range is called Triluminos, while LG has chosen the name NanoCell (or SuperHD LED).
Types of LCD backlighting
Here we will only mention LED backlighting technologies, which are the only ones still in use today.
There are many techniques to excite the liquid crystals in LCD screens by backlighting, but not all of them are the same. The best currently are those using Quantum Dots filter technology as described in the previous section: QLED, Triluminos, NanoCell.
Panasonic also manages to do well with its Wide Colour Phosphor technology. This consists of an optimized LED backlight with a new color filter system that can reproduce up to 98% of the DCI-P3 color space, approaching the 100% coverage offered by the QLED.
But all this is just a drop in the bucket for the high-end LCD market. Most TVs don't have all these features and rely on older, less expensive mechanisms.
Edge LED LCD backlight
With this technique, the LEDs are integrated in bars located at the edges of the screen, so there are no LEDs under the entire surface of the screen. Light reflectors then make it possible to diffuse the light from the LEDs (and thus the image) over the entire screen. This is not the best solution in terms of quality, but it does allow the thickness of the screens to be reduced and the energy consumption of the device to be reduced.
Edge LED LCD backlight with Local Dimming
The principle of LED diodes placed only on the edges with the presence of reflectors to diffuse the light, but with the addition of dynamic LED lighting technology known as "local dimming". This consists of an artificial intelligence that manages the automatic switching on and off of each diode according to the need for brightness. This provides a much more convincing image rendering and deeper blacks than with conventional LED Edge.
LCD backlight Direct LED (or Full LED)
Here, the entire back of the screen is covered with diodes. This provides a more homogeneous backlighting than that offered by the Edge LED. On models that use the three RGB LEDs (red, green and blue), this system also provides more accurate colorimetry. On the other hand, the presence of all these LEDs results in higher energy consumption and requires a certain screen thickness.
Direct LED (or Full LED) LCD backlighting with Local Dimming
The Direct LED (or Full LED) backlighting technology described above can be found, but with the integration of Local Dimming as mentioned above.
We hear more and more about it, OLED is popular. It must be said that this technology offers an extremely interesting benefit-disadvantage ratio compared to conventional LCD solutions. Today, only its price is holding back its expansion. Nevertheless, its variant can be found on most high-end smartphones and even on some mid-range devices from a few manufacturers, with Samsung and Xiaomi leading the way. The Super AMOLED variant is widely used by Samsung for small formats. On TVs, OLED is reserved for premium devices. For PC monitors or laptop screens, this type of screen is very rarely used. Devices equipped with it are very expensive.
OLED stands for "Organic Light-Emitting Diode". A name that sums up its main characteristics and mode of operation perfectly. This technology is based on the presence of organic polymers capable of emitting their own light. This is a totally different process than what is used on LCDs: here, no liquid crystals or backlighting.
The properties of OLEDs make it possible to design particularly thin and lightweight screens, since they do not require backlighting systems or filters to operate. This type of screen is therefore much more practical and can be easily positioned on a wall rather than on a TV cabinet. OLED screens are also more flexible, making it easier to create curved, even foldable or roll-up screens.
In terms of pure performance and image quality, this technology makes an almost flawless. As the viewing angles are very wide, the screen remains very good even when the user is not in front of the screen, where brightness, contrast and colorimetry can degrade very strongly on LCD screens. Of course, the contrast of the OLED is unrivalled, with the screen of true blacks that an LCD screen is unable to produce due to the very nature of its operation. Shades are also better handled by the OLED.
With a response time of less than 0.1 ms, OLED screens are also much faster than any LCD, even TN. As a result, there are no blurring or streaking effects that are sometimes seen when there is movement in the image. Finally, let's talk about power consumption. Without backlighting, OLEDs consume less power than their LCD counterparts. Furthermore, screening a black pixel on LCD is more energy intensive, whereas it is not on OLED because the pixel is turned off.
OLED is capable of providing good brightness, often around 800-1000 nits. While this level of luminance is correct, it is still one of the main weaknesses of OLED, which is much less efficient than competing technologies such as QLED or Micro-LED.
As we explained earlier, Samsung is not the number one OLED supporter for devices with long diagonal screens, such as TVs. But its QLED is not the perfect solution either since this technology still uses backlighting, which has several flaws already described above. The South Korean manufacturer is therefore now banking on Micro-LEDs for the future.
Unlike OLEDs, Micro-LEDs are not based on organic components, but on electronic components (a semiconductor called gallium nitride), which guarantees a much longer lifetime than that offered by its competitor. Samsung talks about 100,000 hours of operation, or about 11 years of continuous use. Another advantage of the Micro-LED is that it is extremely responsive, with response times of less than 1 ms.
These screens are composed of thousands of microscopic LEDs that form the pixels. For each pixel, there is a red LED, a green LED and a blue LED, which gives excellent colorimetry. When a pixel needs to "screen" black, it turns off. The Micro-LED is thus able to offer contrast and deep blacks at the level of what can be seen with the OLED.
However, the brightness promise of the Micro-LED far surpasses that of the OLED, and even the QLED. Samsung reports that its first devices equipped with Micro-LEDs reach 4000 nits, but that the technology is easily capable of surpassing the 10,000 nits threshold. As a reminder, the OLED hardly reaches 1000 nits. The Micro-LED is therefore the assurance of having an excellent image even with the sun's rays entering the living room and to exploit to the maximum image processing technologies such as HDR10+ or Dolby Vision.
Given all these arguments in its favour, why is it that Micro-LEDs are not more established on the market today then? Recent, this technology is still extremely expensive. So much so that we are not yet sure that it will ever be viable for the consumer market. Miniaturization is still a very expensive process, and the high number of microscopic LEDs (size around 30 μm) that are required with this process invariably drive up the price of the final product. Currently, Samsung is not even able to launch mass production because the manufacturing process is so complicated.
We are therefore not likely to see PC screens or televisions equipped with Micro-LEDs in our homes in the near future. However, it is possible that this technology will soon be available on devices with smaller screens, such as smartphones or connected watches, and not necessarily through Samsung. To be continued.
The Mini-LED could be a good compromise between the ambitions of the Micro-LED and the reality of the market. Carried by the Chinese manufacturer TCL, it is a technology based on backlighting. But it improves in all points the capabilities of other LCD techniques (Edge LED or Full LED). The Mini-LED takes up the principle of the Micro-LED consisting in multiplying the number of LEDs under the screen by reducing their size, but without going as far as with the Micro-LED. It is therefore easier and cheaper to produce Mini-LEDs.
Nevertheless, with a size of less than one millimetre, Mini-LEDs are much smaller than conventional LEDs. For example, more than 15,000 of them can be positioned under a 65-inch screen. And TCL claims that it can save a little more space to integrate even more.
With such a wide range of LEDs, LCD technology is nothing like conventional solutions. The result is much more convincing blacks and contrasts, even if you don't reach the level of OLEDs or micro-LEDs, which can turn off the pixels completely. The brightness is also much higher. If the QLED or Micro-LED does not offer the same contrast as the OLED, the Mini-LED does better than the OLED in this respect.
The evolution that everyone could agree on is the association of the Mini-LED with the backlighting principle of the QLED. Together we would then have the advantages of the best LCD technologies available today. This would bring us closer to (but not equal to) the performance of the Micro-LED, but with a much better price/performance ratio. In 2020, the Mini-LED is much closer to achieving a large market share than the Micro-LED. This could happen in a few years. TCL believes strongly in this technology, and other manufacturers are already working on it. In addition to TVs, Mini-LEDs may well come onto premium smartphones and iPad Pro at some point.
How to choose the right screen?
There are many parameters to consider when buying a PC monitor, TV, or other device with a screen. The technologies described above each have their strong and weak points, so it is important to anticipate the consumption of the device to find the product that best suits your needs while taking into account the budget constraints. We detail below some elements to take into account before making a purchase. We focus here on the characteristics directly related to the screen, there are of course other elements to take into account depending on the device, such as its size, its design or the connectors it carries.
Manufacturers communicate a lot about this feature, especially for PC monitors. In particular, they target gamers with promises of very low response time. This is too often a marketing ploy. For starters, many consumers tend to confuse response time with input lag. Input lag is the amount of time it takes for the TV set to process and screen information. For online gaming, a large input lag can be fatal.
Response time is the speed at which a screen can make a pixel of colour change to screen a new picture while erasing traces of the previous picture. In theory, response time is measured like this: the time it takes a pixel to go from white to black and back to white. In practice, most manufacturers measure a "gray-to-gray" response time, which is the time it takes a pixel to switch from one shade of gray to another, in order to communicate a lower response time. For this reason, one should be wary of the indications on the data sheets in this regard for LCDs (the response time in OLEDs is, however, always very low).
In any case, the higher the response time, the more likely it is that you will notice defects (blurring effects and pixel streaks) in the image during sudden movements. This happens especially in games with nervous gameplay or when making sudden camera changes.
You must pay attention to the image definition proposed by the screen of the device you wish to acquire. There are several parameters that you can use to judge which resolution is right for you. The size of the screen first: the larger it is, the lower the resolution is for the same definition. The "thumb stroke" can therefore be dangerous for the image quality.
Then, you must also consider the distance that will under separate from the screen. A TV set is generally located several meters away from us, but a PC or smartphone screen is much closer to the eyes, and a too low definition can then lead to distinguish the pixels and realize that the quality is not incredible (do the test by getting closer to your TV for example).
On a smartphone, an HD definition (720p) is reserved only for small screens, below 5.5 inches. Full HD+ is more than enough for any mobile phone. Of course, we often hold our smartphone close to our eyes, but this amount of pixels for screens of this size is sufficient. The QHD+ offers a difference in quality, but we can easily do without it, especially since mobiles with QHD+ are still very expensive. The 4K is of little interest on a smartphone. Besides, they are very few to offer it (some Sony Xperia).
On laptops and computer monitors, the screen diagonal is longer than on mobile phones. Forget HD, even on a small 13-inch format. 1080p is a minimum, and it is the definition which is very largely in the majority. QHD or 2K remain relatively expensive on products of this type. But you'll have to go through it to enjoy a very good picture quality on a screen larger than 27 inches and that you stand at a short distance from it.
It is probably on the question of the television set that the needs vary the most. Whether your sofa is two or four metres from the TV changes absolutely everything, so it's difficult to cover every possible situation to guide you. Just make sure you don't fall into the trap of the large, low definition TV. Ban HD on a 32-inch or larger screen and Full HD on a screen larger than 43 inches. 4K is now relatively affordable in this sector, so don't hesitate to invest in a compatible TV if you can afford it, where the value for money of 4K on other types of screens is much more questionable.
The type of screen used and the definition are not everything. If you're interested in the top of the line and want a high-end experience, you also need to make sure that some features that further enhance the image rendering are present.
HDR (High Dynamic Range) is a high dynamic range imaging technology. Support for HDR provides the consumer with quality in terms of colorimetry, brightness, contrast, and therefore the level of detail in the image. There are many HDR standards, one of the best known being HDR 10, which is even found on some high-end smartphone screens. The HDR 10+ goes even further by bringing a notion of dynamism. That is to say that the TV will calculate the best settings for the screen of each picture, where the standard HDR 10 is static: the parameters for the same video content are the same from start to finish.
You've probably also heard about Dolby Vision, without really knowing what it refers to. This technology has the same merits as HDR (boosting the general quality of the image by playing on colours, contrast and brightness), but goes even further. Dolby Vision, for example, can theoretically make the most of a luminance of 10,000 nits (there is currently no consumer product offering such a luminosity). With its 12-bit encoding (as opposed to 10-bit for HDR 10), this standard offers a higher image quality than HDR, especially with an even more advanced colorimetry. While HDR is becoming more and more popular, Dolby Vision remains a feature reserved for premium devices.
The refresh rate
This is measured in Hz, indicating the number of times the image is recalculated per second. The higher the value, the smoother and more pleasing to the eye the screen will be. Manufacturers usually use this to attract gamers, as a high refresh rate makes sense for video games. But it also makes sense for many other tasks, even simple web browsing. In particular, the scrolling is much smoother. But just because a screen has a high refresh rate doesn't mean you're going to enjoy it in game. This requires that games are well optimized and that your computer or console is powerful enough.
The standard basic refresh rate for a screen is usually 60 Hz. This can be lowered to 50 Hz on a TV set.
On a smartphone, screens with a refresh rate higher than 60 Hz did not exist before 2019. Their democratization is therefore very recent and for the time being, only high-end oriented models benefit from them. Manufacturers offer either 90 Hz or 120 Hz (at the time of writing, only the Nubia Red Magic 5G offers a 144 Hz screen). Keep in mind that a 90 Hz or 120 Hz screen consumes more power than a 60 Hz screen, so this feature has an impact on the autonomy of the mobile (it can be disabled to switch back to 60 Hz and thus save battery power). Note also that the games available on smartphones are generally not optimized to take full advantage of such a fast refresh, so the effects are not always as stunning as one might think. But even when scrolling, changing screens or animations, you'll notice better fluidity at 90 Hz and 120 Hz.
On PC monitors, the hertz race has been going on for a long time now. As explained above, TN screens easily reach 75 Hz, whereas IPS or VA screens are more at 60 Hz on the basis of the first price. Then each of these technologies can reach a very high refresh rate, but this will cost less on TN. So-called "gamer" monitors generally offer 120, 144 or 240 Hz, the latter still being quite expensive and not very widespread.
You should know that Nvidia and AMD, the two leaders on the graphics chip market, have developed solutions to improve image quality, especially in gaming: G-SYNC for the first one and FreeSync for the second one. Their mission is to synchronize the screen of content (frames per second, or fps) with the screen's capabilities (refresh rate) in order to reduce the problems of slow or jerky images. The presence of either of these technologies is essential for a gaming monitor worthy of the name.
For televisions, increasing the refresh rate beyond the traditional 50/60 Hz is much more expensive than for a computer monitor. There are models with 100, 120 or 240 Hz, but they are clearly high-end. For console gaming, this is not really necessary at the moment. That could change with the arrival of the PS5 and Xbox Series X.
Matte or glossy screen?
An element often forgotten, but one that needs to be taken into account. Matte screens have the advantage of being less affected by glare and reducing user eye strain. They are therefore preferable for office use, or even for gamers who spend a lot of time in front of the screen and do not give much importance to visual quality.
Brighter screens offer better brightness and more vivid colours. When watching video content or gaming, the picture quality is therefore superior to that of matt screens. The difference is all the more visible the brighter the environment in which the screen is located.
Flat or curved?
More and more manufacturers are offering curved screens on their devices. This enhances immersion by giving a little more of a feeling of being at the heart of the action. They are especially useful for video games, hence the fact that most of them are integrated into monitors with a gaming stamp. Curved screens, on the other hand, are more expensive than flat ones.
In the case of computer monitors, it is sometimes better to turn to flat screens to create a multi-screen setup, but curved screens can be considered depending on the configuration you wish to give to your desktop.