Television technology includes OLED, LCD and QD OLED andHDR, 4k, 8k, LCD and micro LCD
At the time of writing there are three core types of TV technology: OLED, LCD and QD OLED. OLED TVs use luminous organic materials to deliver so-called self-emissive images, where each pixel can make its own light independently of its neighbours, resulting in outstanding contrast and colour performance.
LCD TVs combine liquid crystal displays with external backlighting. As a result they deliver less precise light control than OLED, but they can be substantially cheaper. However, premium models can be capable of delivering significantly more brightness than OLED.
QD OLED TVs use an advanced colour system that replaces the traditional inefficient colour filters found with regular LCD TVs with a combination of red and green Quantum Dots and an organic ‘layer’ of self-emissive blue light. This provides the pixel-level light controls of OLED TVs while maintaining purer, more saturated colours in bright picture areas.
There is a fourth, potential future TV technology called Micro LED where individual pixels are made purely using ultra bright LCD technology, without any organic materials. These are difficult to manufacture at the moment, though, so they are many years away from becoming mainstream.
LCD TVs can be made in a variety of ways that can significantly impact their performance. The best technology in performance terms is Mini LED. This uses lots of much smaller lights than you get with normal LEDs to illuminate a TV screen, making it possible to deliver much more localised light control.
Exactly how much light control Mini LED TVs can provide is also down to local dimming. This refers to the way some premium TVs can make different sections of an LCD TV backlight system output different amounts of light for any given shot. The more dimming zones a TV supports, the more accurate its light control will be.
Local dimming can also be used with regular LED TVs, but their reduced number of lights will reduce the local dimming’s effectiveness.
Regular LED/LCD TVs can be illuminated by lights placed either directly behind the screen, or around its edges. Typically, screens that place their lights behind the screen deliver better light control and contrast than edge-lit models.
One final difference worth knowing is that some TVs use IPS screens, while others use VA screens. IPS screens are designed to support wider effective viewing angles than VA panels, but at the expense of contrast. VA panels typically provide better contrast, but lose much of that contrast as well as colour saturation if you have to view them from much of an angle. If you are able to watch your TV from head on for most of the time, VA panels are usually preferable for home entertainment.
It can be hard, though, to find out exactly what technology a particular LCD TV you’re interested in is using. LG uses IPS technology in pretty much all of its LCD TVs, while Samsung uses mostly VA panels. Other brands, however, tend to use an inconsistent and unpredictable mixture of both technologies.
The vast majority of TVs currently available will carry native 4K (also known as Ultra HD) resolutions of 3840x2160 pixels. This is fair enough given that the highest resolution content widely available in the world today is also 4K.
A growing number of high-end TVs, though, carry 8K resolutions of 7680x4320 pixels. But is there really any point to this given that there is practically no native 8K content available to play on such TVs?
In short, it depends on how good an 8K TV’s upscaling processing is. The latest AI-based 8K processing engines from the likes of Samsung, Sony and LG really do manage to improve the quality of 4K pictures for the most part, adding more pixel density, removing jagged edges and enhancing images’ sense of depth in the process of converting them to 8K.
The application of 8K can be particularly useful with very big screens, too – though by the same token its impact reduces exponentially on screens smaller than 75 inches.
High dynamic range images provide a much wider range of brightness and colour than the old SDR images we’ve been used to watching for years. Most TVs these days, even budget ones, support HDR. Supporting HDR is one thing, though; doing a good job of it is another.
The main problem with HDR for budget TVs is brightness. They often just don’t have enough of it – we’d say 500 nits or so is the minimum to make HDR look convincing.
Bear in mind, too, that there are actually four different types of HDR in circulation today. The industry standard system found on any HDR TV is called HDR10. Also now very common is the HLG format, which is used by broadcasters such as the BBC for live streaming in HDR. Sky boxes, too, require HLG compatibility.
The other two formats, Dolby Vision and HDR10+, are rarer. Both are so-called active systems that add extra scene-by- scene picture information to the data stream to help compatible TVs deliver more precise and dynamic HDR images. Dolby Vision is more common in the content world than HDR10+, but frustratingly there is quite a bit of content out there that’s only available in one or the other of those formats, while many TVs also only support one of these formats or the other. LG, for instance, only supports the Dolby Vision active HDR format, while Samsung only supports HDR10+.
Panasonic and Philips make TVs that support all four HDMI formats. Though in truth premium TVs are often clever enough in their management of core HDR10 images to compensate for any potential lack of support for one of the advanced HDR formats.
Gaming features are an increasing part of any premium TV’s repertoire. Especially with the arrival of the PS5 and Xbox Series X, which have introduced two features – gaming in 4K resolution at 120Hz refresh rates and variable refresh rates - that push current TVs to the edges of their capabilities.
If you have one of the new consoles, or a new high-end PC, you will need a TV with at least one HDMI 2.1 port that’s capable of handling at least 40Gbps data rates if you want it to likely be able to handle every graphics feature your console or PC might throw its way.
The once straightforward HDMI connection has become pretty complicated these days. As hinted in the previous section on gaming, there are multiple HDMI formats out there that all support different data capacities and, as a result, different features. You used to be able to feel confident that any TV that claimed to have an HDMI 2.1 port would give you all the latest features, but a recent change in labelling requirements means this is no longer a reliable indicator of cutting edge feature support. So now, if gaming is a big deal to you, you need to check and double check that a TV you’re interested in definitely supports the gaming features you want on at least one of its HDMIs.
Almost every TV now, even budget models, carries a built in smart system. An interface that provides access to video streaming services like Netflix, Amazon Prime Video and Disney+. Not every smart TV system supports all of the most popular apps, though, so it’s worth having in mind which services you definitely want to subscribe to when hunting for a new TV and double checking that a TV model you want definitely supports all of them. Unless you’re prepared to add an external streamer box such as an Apple TV or Amazon Fire TV.
After being sacrificed on the altar of ever-slimmer designs for years, sound quality is back on the TV agenda. Features worth looking out for if you’re not going to be using an external sound system are support for the Dolby Atmos sound system, with its big sound stages and reams of well-placed details; multi-speaker systems that place drivers all around their bodywork for more precise detail placement and a wider, more immersive sound; and dedicated, likely rear-mounted drivers for delivering low frequency sound.