More than 50% of all televisions sold are already equipped with an ultra-high definition (UHD) screen. But what does that actually mean? What advantages does Ultra HD have in practice – and how can you receive programs in UHD? You’ll find the answers in this Tech Guide. Learn the differences between LCD and OLED display technologies, and see what ither important aspects you need to consider when buying a television – succinct as always, to give you a quick overview. Your specialist dealer will be happy to provide you with more detailed information, including about specific models.
Televisions all have flat screens these days, as seen in the sales rooms of your specialist dealer. But on closer inspection, there are some big differences. The colors are brighter and more natural on some screens. Black appears richer and darker, and scenes have more contrast. Some displays are so thin that they can hang on the wall like posters. Much of this has to do with the screen technology.
Most televisions have a liquid crystal display (LCD). The pixels are illuminated by LEDs behind the screen. When the LEDs are located at the edge of the screen (Edge LED), a television can be slimmer as it saves space. However, dimmable zones are relatively large. When you have a television picture with both bright and dark areas, the TV must make a compromise. Sometimes black looks a little too bright. LEDs that are placed directly behind the pixels (Full LED) solve that problem: They use local dimming to dim just the dark areas of the screen, thereby improving the screen’s contrast. You can recognize these televisions by their thicker housing.
OLED combines both advantages: These screens are ultra-flat because their pixels emit the light themselves – the LEDs in the background are no longer needed. This technology delivers the maximum contrast because each pixel can be controlled individually. OLED televisions don’t quite reach the brightness of modern LCD devices, however. If you want to watch TV in the middle of the day in a sun-drenched living room, you should take this into account. Maximum brightness is also important for programs transmitted in HDR. Brightness is specified by the manufacturer in candela per square meter (cd/m2) or nits. The brightest LCD TVs reach 2000 nits, whereas OLED devices reach about half that.
Brightness and contrast are only one piece of the puzzle. At least as important is a television’s color reproduction. Televisions with traditional LEDs are at somewhat of a disadvantage as they neglect parts of the color spectrum (top right). The electronics in the television must compensate for this. In better quality TVs, manufacturers rely on quantum dots (center right): Tiny nanoparticles in the backlighting raise the color reproduction to that of an OLED display. However, picture quality depends on additional factors, including the signal processing in your device. It’s definitely worthwhile to compare televisions at a specialist dealer.
In traditional flat-panel displays, backlighting consists of blue LEDs with a layer of yellow phosphor. The phosphor transforms the light from the LEDs into white light that then passes through the pixels of a liquid crystal display (LCD). Because this LED backlight has little to no green or red, colors do not appear as saturated as on a quantum dot or OLED display.
Especially high-quality LCD televisions use nanocrystals to optimize their backlighting. These quantum dots absorb light and emit it again at a specific wavelength. This is how red and green light can be extracted from the blue LEDs. This technology creates a magnificent picture: Like an OLED screen, quantum dot displays can render the extended color range in Ultra HD signals.
Displays with organic light-emitting diodes (OLED) do not need LEDs behind their screens. The pixels themselves can emit light. Since brightness can be individually controlled for each pixel, no light bleeds into dark areas – black is a deep black. Although OLEDs in red, green and blue are technically possible, today’s televisions use monochrome pixels. Color is provided by the filters in front of the pixels.
Demo videos with high detail sharpness and bright colors are often used for the in-store presentation. For comparison, you should also get a demonstration of normal TV broadcasting. It will show you how good the picture looks with everyday signals.
UHD & HDR
Ultra-sharp and crisp
Ultra HD marks the beginning of a new era of television. UHD signals have four times the resolution than older signals (below). Some manufacturers call their UHD technology 4K. The high pixel count allows for larger screens and a shorter viewing distance: You can sit closer to the television without seeing any blur or pixel patterns. Color reproduction is improved because the image signal contains more information: Instead of 16 million colors, there are now over one billion. UHD signals are provided by television stations, streaming services and Ultra HD Blu-rays. But digital photos and smartphone videos also look better on UHD TVs.
TV programs with an extended contrast range (High Dynamic Range) provide an additional boost in quality. HDR signals convey more details in dark and bright scenes, resulting in a crisper and more natural picture. Unlike Ultra HD, there are several different standards. HDR-capable TVs must be able to recognize and process these signals to display the picture at full quality. HDR 10 can be displayed on all HDR-capable devices. This has been the standard used by Blu-ray and the Internet for a long time. Television stations use HLG (Hybrid Log Gamma) for transmission. And then there is HDR10+ and Dolby Vision: both of these systems continuously adjust their contrast settings based on the program content, ensuring an optimal picture in every scene.
Resolution The Ultra HD format has twice as many pixels in both height and width as Full HD. This means that the resolution is four times higher: around 8.3 million pixels. In particular, larger television screens benefit from the higher number of pixels: UHD becomes particularly noticeable at 55 inches (140cm, diagonally) and upwards. On smaller screens, a Full HD display is often sufficient. By now, that’s the standard, even in 22-inch TVs. Only a small number of devices still use a HD resolution. (1280×70). For comparison, Ultra HD is 3840 x 2160.
A wide variety of programs
The range of television channels is huge, from a few dozen channels available via an antenna (right) to many hundreds of channels available via satellite. Some of them are free. The rest are available in an encrypted form to paying customers – such as the HDTV channels provided by private broadcasters or pay TV services such as Sky.
Special technology is required in order to receive and watch encrypted channels. This may be built into the device, in which case you only need a subscription card to unlock it, or it may be added using a module. Almost all televisions have a port on the housing that allows this: the common interface. Some televisions have two, allowing several subscriptions to be used simultaneously.
How a television receives a program depends on its built-in technology: It needs a separate receiver for each signal (right). Twin-tuners can display one program on the screen and simultaneously record another on a hard disk.
Antenna (DVB-T, DVB-T2 HD)
The switch to DVB-T2 is expected to be complete in mid-2019. Public channels will then be able to supply an Ultra HD signal. In many regions, around 20 additional private channels in HD will be available. These are encrypted and can be received on subscription.
Cable (DVB-C, DVB-C2)
A wide range of TV channels in both SD and HD quality is available via a cable TV connection. Some network providers also provide programs in Ultra HD. Cable providers’ packages also include telephone and internet access, as well as access to online video services.
A satellite dish provides access to the largest number of channels by far. In additional to SD and HD channels from all over the world, many Ultra HD channels are available. Advantage: Similar to an antenna connection, there are no subscription costs for free TV programs.
Home network (Sat>IP, TV>IP)
Devices with a wireless tuner do not get their signal directly from a TV connection, but via a built-in receiver. An IP server distributes the signal via a home network, where various devices can access it – even over WiFi.
You don’t need a satellite or an antenna to receive television over the internet. Programs are delivered to your television as a video stream. You can subscribe to channels just as you would to your DSL or mobile phone plans. A fast internet speed is necessary for the high picture quality of Full HD or Ultra HD.
Different reception methods can be easily combined: If there is no cable or satellite connection in a room, an indoor antenna can be used. Or a smart television can receive programs from internet services like Magine and Zattoo.
More than just a television?
Good picture quality is important. However, the other features built into televisions can influence your viewing pleasure equally. Some features, like a twin-tuner, USB recording or a wireless connection are widely available. Other features are only available on certain brands.
One exclusive extra is an LED light that illuminates the wall behind the TV and automatically changes color to match the on-screen content (top). However, most of these technologies are rather more hidden. Some TVs can use wireless speakers or provide surround sound. Some models switch channels amazingly fast, while others can transmit signals to second and third TVs within the house (TV>IP).
The High Definition Multimedia Interface port, HDMI for short, is the most important port on a television. It connects the TV to a game console, Blu-ray player, AV receiver and more. All modern home cinema devices are equipped with a HDMI port. It’s a good idea to make sure your television has more than one. For UHD and HDR , you’ll need HDMI version 2.0 or higher. Your television should also support the HDCP 2.2 copy protection technology. Models with the official Ultra HD logo meet this requirement. However, this symbol says nothing about the picture quality. That’s why there is another manufacturer-independent label: Ultra HD Premium. It is used to identify televisions that meet particularly high standards.
Even the smallest televisions now have a USB port. This allows you to display photos and videos from external devices on your screen. If you have a smart TV, you can do this via your home network, where the TV can be reached wirelessly or via a LAN cable. The advantage: you no longer need to copy your photos to a USB stick. Your TV can fetch them directly from your smartphone or WiFi-enabled digital camera. This is the same for playing movies and music from a media server. And then of course, there is the internet with its online video platforms, streaming services and cloud storage. There are apps for many of these services, but they are not necessarily available on all televisions. The choice depends on the brand of television. Do you subscribe to an online service that your favorite TV doesn’t support? No problem: you can usually add the missing service via a streaming stick or a player attached to the TV’s HDMI port. These inexpensive devices can be used to add these features to older televisions without networking and smart features.
Some televisions are additionally useful around the house. They can show you images from surveillance cameras, the contents of your refrigerator, or the progress of that roast in your oven. Some models can even take control of smart devices: using an internal or external control device, for example, they can turn lights on or off, or regulate your heating. This means that no one must reach for their smartphone while watching TV – the TV remote control can be used instead.
Even if you don’t want to use internet-based services via your smart TV, you should still connect the device to your home network from time to time. This will allow your television to receive software updates and may include improvements to its features.
Voice control lets you control your television by speaking to it: switch it on, change the volume, or change the TV program. One of several variants work on most TVs. You can operate a television that is connected to a digital assistant hand-free.
A voice control microphone receives the commands and forwards them to Alexa or the Google Assistant.
Televisions with voice remote control have the necessary technology built-in. Press a button to activate the microphone, then give it a command.
A voice-control infrared hub renders even older, non-wireless TVs voice controllable. Ask your specialist dealer for such a universal remote control.
You can program, archive and play back TV programs on demand with any television that has a recording feature. A commercially available hard disk is used for storage, connected to a USB port on the TV. Some manufacturers install this directly inside the TV housing, where all you need to do is select a program in the electronic program guide (EPG) (right). The rest is done automatically
Smart televisions are equipped with a LAN port and a wireless connector. They can receive additional channels over the internet. For example, some TV stations provide programs with extra information as HbbTV (hybrid broadcast broadband TV). Press the red teletext button on your remote control to open the on-screen menu with a selection of options (right).
Apps & games
Just like on a smartphone or tablet device, you can download apps from the internet to your smart TV. A selection of apps is usually pre-installed on these televisions, including video apps from streaming services like Netflix or Maxdome, and media libraries for various channels. Televisions that contain powerful processors are also suitable for gaming. The choice of available apps depends on the operating system installed on your television.
Interior designers have long dreamed of TVs that hang on the wall like picture frames. With modern display technology, this is becoming a reality: OLED screens are so flat that they are hardly noticeable from the side. The thinnest require neither a base, nor a mounting device: magnets hold them directly against the wall. Manufactures of some LCD devices supply gapless mounts to achieve a similar effect.
Where wide plastic or aluminum frames used to dominate television displays, there is now only a narrow edge. The picture is no longer limited, opening up new design possibilities. Anyone buying a television today not only has a choice of flat or curved displays, they can choose from any number of housing shapes and materials.
Real wooden surfaces and high-quality fabrics are moving televisions out of their technology corner, transforming TVs into furnishings that are worth being seen. Manufacturers are also paying more attention to the back of the device. This is almost a necessity in light of the increasing screen sizes. A 55-inch diagonal is more easily concealed when it is as an attractive piece of furniture.
For wall-mounted devices, a gallery mode completes the illusion of a picture on the wall. It can display your favorite photos or paintings complete with a digital mat. Some TV manufacturers provide photos of works of art from renowned galleries like the Prado in Madrid, or the Victoria and Albert Museum in London as downloads. If your TV comes with a removable frame in a variety of colors, it is hardly distinguishable from the real work of art (see below). Devices with a liquid crystal display are particularly suitable for use in galleries as they are immune to image burn-in. On OLED screens, still images can leave slight shadows after several hours. However, this hardly ever happens in practice: Manufacturers use special technologies to erase such traces, or prevent them from forming in the first place
Televisions with an external connection box (below) make installation easy: a single thin cable connects to the display, which can be laid almost invisibly. Blu-ray players or gaming consoles disappear together with the box in the cabinet.