When buying a new TV or a monitor for our desktop PC, it is important for potential buyers to evaluate the type of screen we need. As many of you already know, on the market it is possible to find very different devices, and that for their peculiar characteristics guarantee a certain type of performance.
In stores, whether physical or online, we can in fact see TVs and monitors equipped with different technologies, moreover in constant evolution. Among the more traditional LCD, VA, IPS and TN, the selection has become much wider in recent years thanks to the introduction of Nanocell technology, presented by LG during the 2017 CES in Las Vegas.
This promises to achieve the color rendering qualities of OLED screens, but at a much lower price, and has been deliberately introduced as an antithesis to the Quantum Dot TVs of Samsung Display, which have always been renowned for their visual purity and the detail offered to the end consumer. So let’s find out what it is in more detail, and why it is a preferable solution to the common LCD.
NanoCell: what is it and what does it mean
One of the most notorious problems that LCD screens carry with them is that of color rendering and depth, which loses quality compared to the old CRT and OLED screens. Manufacturers of televisions and monitors have therefore tried to overcome this criticality by developing new technologies, among which stands out the NanoCell introduced by LG.
The South Korean giant, with this innovation, promises to reflect better colors, moreover at a very affordable cost. To understand how they work and what are the advantages of NanoCell screens, however, we must make a quick introduction, describing how a modern LED LCD TV is composed. Traditionally, the panel of a TV is divided into several layers, namely the backlight, the RGB filter, Red, Green and Blue, and the liquid crystal panel.
More specifically, the backlight is composed of LEDs that emit white light. Light that passes through red, green and blue filters – the so-called sub-pixels – and then arrives at the liquid crystals, responsible for “building” the visible image on the screen. Not coincidentally, the colors of the image we see are the variable combination of the colors of the three red green and blue subpixels that make up each dot present.
To explain it even more simply, if cathode ray tube TVs capture color by varying the voltage, OLED and LCD TVs give a color to each individual pixel. And they do this using different subpixels, which in a combined way form the different colors that are on the panel. The fidelity of color reproduction, of course, is closely linked to the way in which the subpixels manage to separate the three colors correctly, along with the ability of the filters to block out unwanted part of the light spectrum.
For a reproduction of the color gamut closer to reality, and that still has nothing to envy to that of cathode ray tube TV and OLED, the giants of the industry have pursued the goal of clearly separating the three main colors acting with greater precision in the representation of all the different shades.
A wise choice, if we take into account that one of the most obvious issues affecting LCD screens is the fact that the density per pixel per inch is so great that the subpixels of each color component are glued together. This means that the light they emit affects those around them, distorting the final color they display.
How NanoCell Technology Works
That’s not all, because in defining how NanoCell technology works, we must also consider that the saturation of a color, which technicians also call purity, depends on the intensity of light and the wavelength spectrum over which it is distributed. A color defined as pure can be obtained when the wavelengths of light are precise and clean, which means that there are no interferences or phase shifts.
Color saturation therefore represents the intensity of a specific hue. In detail, we can say that a very saturated hue has a vivid color, while as the saturation decreases the color becomes softer and tends to shades of gray. But if saturation becomes excessive, it tends to distort colors and cause image problems, especially on skin tones. And all colors generally lose their naturalness.
With NanoCells, we then try to optimize these filters to cleanly separate colors without reducing panel brightness, trying to keep the promise of much better color rendition. To understand how, let’s remember that the proximity of pixels to each other means that light from the subpixels ends up affecting the neighboring subpixels, distorting the color of all the elements involved.
We must also keep in mind that as the screen resolution increases, the distance between pixels decreases and thus the problem becomes much more noticeable. Going from a 1080p screen resolution to a 4K screen means doubling the number of pixels per inch, a change that also occurs when moving from 4K to the higher-performance 8K.
So it was necessary to develop new technology, such as nanocells, to overcome the problem. The answer given by the use of NanoCell uses a light filter in each sub-pixel so that the light does not go beyond a single pixel, so that it does not affect the adjacent ones and their values are not annoyingly altered in the eyes of the viewer.
The advantages (and disadvantages) of nanocells
The Nanocell technology is based, as already mentioned, on nanocells. These are tiny particles, just 1 nanometer in size, which have the ability to easily return natural colors without any kind of distortion, and moreover from every possible viewing angle. The nanotechnologies used consequently improve contrast and represent more real colors, enriching the TV market with models that can represent all the nuances of different colors, and therefore can have a very wide chromatic range.
The main advantage of NanoCell screens is to offer an image quality very close to that which characterizes OLED screens, with a significantly higher price, and far superior to classic LCD screens. The viewing angle is excellent, with an amplitude of 178ยบ in both directions and without the age-old problem of burnout that OLED screens notoriously suffer from.
At the same time, they circumvent the fading problem of LCD screens. However, being an LCD technology, they necessarily need backlighting, which means that purity and chromatic gradation of each color are not represented in the same way.
Despite some smearing, NanoCell technology uses nanoparticles to absorb wavelengths considered to be in excess, expanding the color gamut and going on to improve color purity. In contrast, conventional LCD screens use different filters that can cause color distortion and light reflections that are less than optimal.
Quality is also enhanced by a focus on high contrast, which is understood to be the ratio of the highest, brightest value to the lowest, darkest value of the brightness of a specific image. By their very nature, televisions that are based on LCD technology cannot achieve the infinite contrast typical of OLED TVs, but some models of televisions with NanoCell implement what is called FALD or Full Array Local Dimming, which aims to reduce the level of illumination in certain areas of the screen, to give a better representation of blacks.
The combination of NanoCell and FALD offers better image quality and allows us to achieve the quality of OLED screens, placing the LEDs behind the entire panel. High contrast actually gives way to deep blacks that add depth to all colors without necessarily increasing saturation too much.
Another advantage of NanoCell technology is that it offers viewers a wide viewing angle. Something that might seem minor, but is actually an extremely important element. Not only that, this particular type of technology is able to enhance 4K HDR content, i.e. in high resolution and high color gamut, reproducing images faithfully, just as they were conceived by the filmmakers during the production of their film or a fascinating television series.
In spite of the many advantages, and a lower price compared to OLED competitors, NanoCell screens have proven in the field to suffer from higher energy consumption. This is precisely why it is a solution that has not yet been standardized on smaller screens, such as laptops, tablets and smartphones, effectively closing the door on its use. Still, they remain a potential threat to OLEDs, and a tremendous opportunity for consumers to enjoy optimal images at not too much cost.