Modern TV use two main display technologies - either LCD with LED backlighting or OLED. Let's take a closer look at them both.
The way LCD technology works is that we have a separate backlight layer covered by a layer of liquid crystals. These crystals are rotated by different voltage levels, making them either transmit or not transmit light. This modifies the displayed colours, but also changes the local brightness.
If the TV wants to display black somewhere, it will completely 'close' the liquid crystals at that point. These then let in only a minimum of light, causing the image to appear black at that location. But in reality it's only very dark grey or blue, because the LED backlight illuminates the whole screen with the same intensity, and even shuttered liquid crystals do let some light through.
That's why TV manufacturers have come up with so-called Local Dimming. This divides the LED backlight into larger segments, which the TV is able to individually brighten, dim, or switch off completely. As a result, LCD/LED TVs with Local Dimming have significantly higher contrast and can display true blacks. There are limits to this technology, however, as even the best LED TVs only have thousands of these zones, with millions of pixels. The quality of dimming in close-up scenes is therefore not as good as in OLED technology.
OLED uses so-called organic diodes, which can be so small that they can be used directly as pixels. This means that OLED TVs have no backlight. Instead, each pixel emits light independently, so each pixel can be individually lit or turned off as needed. With this solution, it is therefore easy to achieve deep flawless blacks even when displaying fine details. For this reason, OLED is considered to be the most advanced TV display technology currently available, not only because of its high contrast but also because of its beautifully saturated colours.
It has its drawbacks, of course. The biggest one is the price, because you simply have to pay extra for an OLED TV. The second disadvantage is the theoretical risk of pixel burn-in. Burn-in manifests itself in a permanent drop in contrast in places where the image remains static for a long time, typically on TV station logos. At present, however, there is no need to worry about burn-in too much as you are unlikely to encounter it if you use your TV normally.
Other terms related to television display technology:
Despite its similarities, QLED is nothing like OLED. It is an LCD technology with LED backlighting assisted by the so-called quantum dots. These are miniature particles that improve the TV's imaging properties in the colour field. A QLED television is capable of displaying more colours than a regular LED television. The picture is therefore more vivid and looks much better overall.
Mini LED is a technology that uses much smaller light emitting diodes than regular TVs. They should be no more than 0.2mm in size. If a TV boasts Mini LED technology, it's basically boasting about the quality of its backlighting. The smaller diodes make it possible to reduce the Local Dimming zones and more accurately backlight the image on the TV. The result should therefore be close to what OLED provides. But mini LED technology is still LCD with all it entails, except with a new type of backlighting.
Micro LED is probably the real technology of the future. Here, the diodes are even smaller than in Mini LEDs and can therefore be used not only as backlight elements, but as pixels themselves. Micro LEDs therefore work in a similar way to OLEDs. The pixels themselves glow, and each one can be switched off to achieve absolute, flawless black even in the smallest details. The key part is that Micro LED does not use organic diodes, which have a high power consumption and are theoretically at risk of burn-in.
Micro LED takes the best of both LCD and OLED. The only problem is the price. These TVs are currently exorbitantly expensive, as evidenced, for example, by the 110" Micro LED TV Samsung MNA110MS1A. However, we can expect the prices to drop in the future, which will bring Micro LED TVs into ordinary living rooms.
As of 2021, Samsung-branded TVs that use a quantum dot layer along with Mini LED backlighting, a backlight that has a large number of local dimming zones, are referred to as NEO QLED.
Read more in our article Samsung Neo QLED: Next Gen TV Technology Has Arrived.
QNED is very similar to Samsung's QLED, but in this case it's LG. It is also a combination of quantum dot technology and Mini LED backlighting. The "N" in the QNED name refers to "NanoCell", which is the general marketing branding for LG's LED TVs.
Laser TV is not a traditional type of TV, as it uses a short-throw projector to display content, typically in conjunction with a special projection screen. This is tailored to better reflect light from the projector and, in turn, prevent ambient light glare. The main advantage of this solution is the ability to achieve huge diagonal image sizes, while maintaining high contrast even in daylight, as we are used to from conventional TVs.
Direct LED and Edge LED
Direct LED means that the LED backlighting of the TV is evenly distributed under the entire screen area. The main advantage is its uniform performance. In more expensive TVs, Direct LED backlighting also provides Local Dimming.
In Edge LED, on the other hand, we find the diodes placed only around the perimeter of the screen, from where the light is guided to the centre. This makes these TVs thinner, but it also increases the risk that the backlight will not be completely even.