What is a quantum dot display? Plasma TV PDP. The graceful curve of the KS9000 and KS7500 screen

What does the abbreviation QLED mean?

It's simple: Q stands for “quantum dots” or “quantum dots”, and LED stands for “ light-emitting diode"or, more simply put, the liquid crystal screen familiar to all of us with LED backlight.

If you are reading this article from a monitor or laptop screen released after 2010, then most likely you are looking at an LED display. It turns out that when they talk to you about QLED, then we're talking about just oh new technology production of LCD screens.

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QLED TV as a Hypnotoad.

What are quantum dots?

Quantum dots are nanocrystals that, depending on their size, can glow a certain color. When producing matrices, of course, you need red, green and blue dots. Do you remember that it is from these three components in the RGB range (Red, Green, Blue) that all other colors are made up?

The word “quantum” clearly hints that the emitters described are so tiny that they can only be seen under a very powerful microscope. For comparison, the size of a DNA molecule is 2 nanometers, while the sizes of blue, green and red quantum dots do not exceed 6 nanometers. You can roughly compare this with a visible value: on average, the thickness of a human hair is 60-80 thousand nanometers or 0.06-0.08 mm.

The glow color of quantum dots depends on their physical size. Modern industry can control it during production with atomic precision.

By the way, quantum dots were invented back in 1981, and they were obtained by the Soviet physicist Alexei Ekimov. Then in 1985, American scientist Louis Bras discovered that these elements can glow when exposed to radiation, and the color of the glow depends on the physical size of the nanocrystal.

So why are we talking about quantum dots just now? Because technology has only recently reached a level where industry can obtain crystals the right size with atomic precision. Samsung presented the first prototype of a QLED screen, and this significant event happened in 2011.

How does a TV matrix with quantum dots work?

By absorbing radiation from blue LED backlights, quantum dots re-emit it with a clearly defined wavelength. This produces purer basic (the same blue, green and red) colors than in conventional LED matrices.

At the same time, the filters used in LED TVs are excluded from the design as unnecessary. There they are needed to improve the accuracy of color display, but reduce the brightness of the image because Passing through the filters, the backlight radiation is refracted, losing its intensity. At the same time, color saturation also decreases.

Flagship QLED TV Samsung.

Why are QLED screens so good?

QLED displays are designed in such a way that minimal distortion is introduced into the light structure when forming an image. As a result, it is possible to achieve very accurate color reproduction: the picture is bright, saturated, the shades are even, and the color gamut is very, very wide.

To produce QLED TVs, there is no need to completely re-equip the lines at factories, because we are simply talking about a more expensive and advanced technology for the production of LED screens.

It is stated that QLED matrices do not fade over time, because they are not based on organic materials, like OLED.

Are QLED and OLED the same thing?

No, these are fundamentally different technologies.

OLED screens are based on carbon-based organic materials. The pixels in these matrices light up a certain color due to the influence of current. As a result, there are not only no filters, but also no backlighting in general. Actually, this is how we get that “deep black color” that is written about in all the reviews. If the pixel is not lit, it will be perfectly black.

The technology for producing OLED displays with large diagonals is complex and expensive, and regular talk that it is “about to become much cheaper” is not yet supported by anything. Screens with quantum dots are already a little cheaper and there is also a basis for future reduction in price.

One of the main complaints about OLED screens is that such matrices burn out over time. This is true, but there is no reason to worry: years must pass before the deficiency manifests itself. LG, for example, claims a service life of 10 years for its OLED TVs, provided they are turned on 8 hours a day.

Comparison of QLED and OLED technologies at one of Samsung's presentations. When looking at this frame, keep in mind that the photograph does not convey the real color quality, and the settings of both TVs are unknown.

We can definitely say that QLED Samsung screens on this moment Brighter than LG OLED displays. In the first case, the declared peak brightness is 1500-2000 nits, in the second - only 1000 nits. We're talking, of course, about model range beginning of 2017.

But the quality of color rendering in comparison is an open question. Of course, Samsung says that quantum dots are cooler than AMOLED, and LG says exactly the opposite, but no one has yet conducted independent tests.

By the way, if this is suddenly important for someone, then QLED TVs are noticeably thicker than “boxes” with AMOLED.

How much do QLED TVs cost?

In short, it's very expensive.

The most “budget” QLED Samsung TV costs 140,000 rubles - this is a 49-inch model from the “junior” Q7 line. For the 55-inch curved Q8C they are already asking 220,000 rubles, and the most expensive in Russia today is the 65-inch version of the same model, it will cost 330,000 rubles.

Until recently, organic light-emitting diode (OLED) TV displays were considered the last word in the development of display technologies. However, progress does not stand still and a new product is being brought to the attention of buyers - liquid crystal displays based on quantum dots.

Translated from English it actually means quantum dots. They are tiny particles with a diameter of only a few nanometers. It is impossible to see them with the naked eye. But this is their main advantage. By adjusting the size and giving a certain shape to this semiconductor, it is possible to exercise precise control over the electrical conductivity, and therefore change the color of the light emanating from the quantum dot. Large dots will appear red, smaller ones will appear blue, and medium ones will appear green. Thanks to its stability, as well as precise control over particle sizes, it is possible to obtain exactly the color that is needed. In this case, the given shade will be almost eternal.

Advantages of nanocrystals over LEDs

The displays of modern LED-backlit LCD TVs have a major drawback: their images depend on LEDs, which emit impure light. White light, with a narrow color spectrum. There are certain technologies that make it possible to bring white closer to the ideal, but the resulting colors still do not have the same intensity (green and blue will be brighter than red). To somehow smooth out this difference they use special settings colors on the TV by lowering the blue and green values, but the result is a much duller picture than necessary.

The problem of finding a source of ideal white light, which would provide the entire light spectrum with colors of the same intensity when refracted, was solved by using quantum dots.

Thus, when creating displays using nanocrystals, the following technology was used. Quantum particles of red and green shades are applied to a special film. They are not divided into subpixels as in the RGB model, but are simply mixed with each other. Behind this layer are LEDs of blue color. When hit by light from the diode, the quantum dots begin to emit their red and green colors. And just in the process of mixing all three colors, the desired source of ideal white light is obtained. This provides correct color rendering without distortion of the color spectrum and loss of color intensity.

Thus, the quantum mechanism will allow us to resolve whole line problems encountered with conventional backlit LCD displays. Among the main advantages of QD-LED technology are the following:

Application of an ideal white light source.
No problems with loss of contrast and brightness. All colors of the light spectrum have the same degree of intensity. No one color dominates the other.
Increased color realism by more than 50 percent (about a billion shades).
Color saturation increases by 40 percent.

Advantages of nanocrystals over OLED

OLED displays, the operation of which is based on organic light-emitting diodes, have become the next step in the development of electronics. Compared to conventional liquid crystal OLED displays have a number of advantages:

image quality does not change depending on the viewing angle;
no backlight;
the weight and dimensions of the product are reduced;
The brightness and contrast of the image increases.

However, despite all the advantages, this technology has a number of disadvantages. For example, OLED displays have a short service life. Blue LEDs have a limited service life of several years of continuous operation. And when they fail, color accuracy is significantly distorted. Image brightness also affects display life and power consumption: the higher the brightness, the shorter the lifespan and the higher the power consumption. But most significant problem the use of organic LEDs is their mass production . This technology requires complete replacement

The use of quantum dots requires only minor changes and improvements to existing pipelines. This will directly affect the final cost of the displays. In addition, the use of nanocrystals solves the problem of color rendering fragility and energy efficiency. The result is high quality image, comparable to OLED while being more affordable to purchase. / Read more on our website.

Thus, quantum dots become a new milestone in the development of liquid crystal displays. Although who knows, maybe something new will be just around the corner scientific discovery, which will change our current ideas about advanced technologies.

Quantum dots are tiny crystals that emit light with precisely controlled color values. Quantum dot LED technology significantly improves image quality without affecting the final cost of the devices, in theory :).

Conventional LCD TVs can only cover 20-30% color range, which the human eye can perceive. The image is not very realistic, but this technology is not focused on mass production of large display diagonals. Those who follow the TV market remember that back in early 2013 Sony introduced the first TV based on quantum dots (Quantum dot LED, QLED). Large manufacturers TVs will release quantum dot TV models this year; Samsung has already presented them in Russia under the name SUHD, but more on that at the end of the article. Let's find out how displays produced using QLED technology differ from the already familiar LCD TVs.

LCD TVs lack pure colors

After all, liquid crystal displays consist of 5 layers: the source is white light emitted by LEDs, which passes through several polarizing filters. Filters located at the front and rear, together with liquid crystals, control the passing light flux, reducing or increasing its brightness. This happens thanks to pixel transistors, which affect the amount of light passing through the filters (red, green, blue). The generated color of these three subpixels, on which filters are applied, gives a certain color value of the pixel. The color mixing happens quite smoothly, but it is simply impossible to get pure red, green or blue this way. The stumbling block is filters that transmit not just one wave of a certain length, but a whole series of waves of different lengths. For example, orange light also passes through a red filter.

An LED emits light when voltage is applied to it. Due to this, electrons (e) are transferred from the N-type material to the P-type material. N-type material contains atoms with an excess number of electrons. P-type material contains atoms that lack electrons. When excess electrons enter the latter, they release energy in the form of light. In a conventional semiconductor crystal, this is typically white light produced by many different wavelengths. The reason for this is that electrons can be in different energy levels. As a result, the resulting photons (P) have different energies, which results in different wavelengths of radiation.

Light stabilization with quantum dots

IN QLED TVs Quantum dots act as a light source - these are crystals only a few nanometers in size. In this case, there is no need for a layer with light filters, since when voltage is applied to them, the crystals always emit light with a clearly defined wavelength, and therefore color value. This effect is achieved by the miniscule size of a quantum dot, in which an electron, as in an atom, is able to move only in limited space. As in an atom, the electron of a quantum dot can only occupy strictly defined energy levels. Due to the fact that these energy levels also depend on the material, it becomes possible to specifically tune the optical properties of quantum dots. For example, to obtain red color, crystals from an alloy of cadmium, zinc and selenium (CdZnSe), the size of which is about 10–12 nm, are used. Cadmium and selenium alloy suitable for yellow, green and blue colors, the latter can also be obtained using nanocrystals from a zinc-sulfur compound with a size of 2–3 nm.

Mass production of blue crystals is very difficult and expensive, so introduced in 2013 by the company Sony TV is not "thoroughbred" QLED TV based on quantum dots. At the back of their displays is a layer of blue LEDs, the light of which passes through a layer of red and green nanocrystals. As a result, they essentially replace the currently common light filters. Thanks to this, the color gamut compared to regular LCD TVs increases by 50%, but does not reach the level of a “pure” QLED screen. The latter, in addition to a wider color gamut, have another advantage: they save energy, since there is no need for a layer with light filters. Thanks to this, the front part of the screen in QLED TVs also receives more light, than in regular TVs, which transmit only about 5% of the light flux.

QLED TV with Quantum Dot Display from Samsung

Samsung Electronics presented premium TVs in Russia made using quantum dot technology. New products with a resolution of 3840 × 2160 pixels turned out to be not cheap, but flagship model completely valued at 2 million rubles.

Innovations. Curved TVs Samsung SUHD based on quantum dots differ from common LCD models by more high performance color rendering, contrast and power consumption. Integrated SUHD Remastering Engine allows video content to be upscaled low resolution in 4K. In addition, the new TVs received Peak Illuminator and Precision Black intelligent backlighting, Nano Crystal Color technology (improves color saturation and naturalness), UHD Dimming (provides optimal contrast) and Auto Depth Enhancer ( automatic setting contrast for certain areas of the picture). IN program basis TVs lies in the operating room Tizen system with updated Samsung platform Smart TV.

Prices. The Samsung SUHD TV family is presented in three series (JS9500, JS9000 and JS8500), where the cost starts from 130 thousand rubles. This is how much the 48-inch model UE48JS8500TXRU will cost Russian buyers. The maximum price for a TV with quantum dots reaches 2 million rubles - for the UE88JS9500TXRU model with an 88-inch curved display.

New generation TVs using QLED technology are being prepared South Korean Samsung Electronics and LG Electronics, Chinese TCL and Hisense, as well as Japanese Sony. The latter has already released LCD TVs made using quantum dot technology, which I mentioned in the description of Quantum dot LED technology.

December 4, 2016 at 10:35 pm

Quantum dots and why they are installed

Quantum technologies,
Monitors and TV

Good day, Habrazhiteliki! I think many people have noticed that advertisements about displays based on quantum dot technology, the so-called QD – LED (QLED) displays, have begun to appear more and more often, despite the fact that at the moment this is just marketing. Similar to LED TV and Retina, this is a technology for creating LCD displays, using LEDs based on quantum dots as backlight.

Your humble servant decided to figure out what quantum dots are and what they are used with.

Instead of introducing

Quantum dot- a fragment of a conductor or semiconductor, the charge carriers of which (electrons or holes) are limited in space in all three dimensions. The size of a quantum dot must be small enough for quantum effects to be significant. This is achieved if the kinetic energy of the electron is noticeably greater than all other energy scales: first of all more temperature, expressed in energy units. Quantum dots were first synthesized in the early 1980s by Alexei Ekimov in a glass matrix and by Louis E. Brous in colloidal solutions. The term "quantum dot" was coined by Mark Reed.

The energy spectrum of a quantum dot is discrete, and the distance between stationary energy levels of the charge carrier depends on the size of the quantum dot itself as - ħ/(2md^2), where:

ħ - reduced Planck constant;
d is the characteristic size of the point;
m is the effective mass of an electron at a point

If we talk in simple language then a quantum dot is a semiconductor, electrical characteristics which depends on its size and shape.

For example, when an electron moves to a lower energy level, a photon is emitted; Since you can adjust the size of a quantum dot, you can also change the energy of the emitted photon, and therefore change the color of the light emitted by the quantum dot.

Types of Quantum Dots

There are two types:

epitaxial quantum dots;
colloidal quantum dots.

In fact, they are named after the methods used to obtain them. I will not talk about them in detail due to large quantities chemical terms (Google to help). I will only add that using colloidal synthesis it is possible to obtain nanocrystals coated with a layer of adsorbed surfactant molecules. Thus, they are soluble in organic solvents and, after modification, also in polar solvents.

Quantum dot design

Typically, a quantum dot is a semiconductor crystal in which quantum effects are realized. An electron in such a crystal feels like it is in a three-dimensional potential well and has many stationary energy levels. Accordingly, when moving from one level to another, a quantum dot can emit a photon. With all this, the transitions are easy to control by changing the dimensions of the crystal. It is also possible to transfer an electron to a high energy level and receive radiation from the transition between lower-lying levels and, as a result, we obtain luminescence. Actually, it was the observation of this phenomenon that served as the first observation of quantum dots.

Now about the displays

The history of full-fledged displays began in February 2011, when Samsung Electronics presented the development of a full-color display based on QLED quantum dots. It was 4 inch display controlled by active matrix, i.e. Each color quantum dot pixel can be turned on and off by a thin film transistor.

To create a prototype, a layer of quantum dot solution is applied to a silicon circuit board and a solvent is sprayed on. Then a rubber stamp with a comb surface is pressed into the layer of quantum dots, separated and stamped onto glass or flexible plastic. This is how stripes of quantum dots are applied to a substrate. In color displays, each pixel contains a red, green or blue subpixel. Accordingly, these colors are used with different intensities to obtain the most more shades.

The next step in development was the publication of an article by scientists from the Indian Institute of Science in Bangalore. Where were quantum dots described that not only luminesce? orange, but also in the range from dark green to red.

Why is LCD worse?

The main difference between a QLED display and an LCD is that the latter can cover only 20-30% of the color range. Also, in QLED TVs there is no need to use a layer with light filters, since the crystals, when voltage is applied to them, always emit light with a clearly defined wavelength and, as a result, with the same color value.

There was also news about the sale computer display on quantum dots in China. Unfortunately, I haven’t had a chance to check it with my own eyes, unlike on TV.

P.S. It is worth noting that the scope of application of quantum dots is not limited only to LED monitors; among other things, they can be used in field effect transistors, photocells, laser diodes, they are also studying the possibility of using them in medicine and quantum computing.

P.P.S. If we talk about my personal opinion, then I believe that they will not be popular for the next ten years, not because they are little known, but because the prices for these displays are sky-high, but I still want to hope that quantum the points will find their application in medicine, and will be used not only to increase profits, but also for good purposes.

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For five years, Samsung engineers have perfected the technology to produce super-high resolution SUHD displays at quantum dots. The matrix of this type of monitor is built on 1-5 nanometer particles (1000 times smaller than a hair), which emit light depending on the voltage and size.

The screen matrices of the 7-series models are represented by three diagonals:
49” – 78,000 rub.;
55” – 102,000 rubles;
65′‘ – 170,000 rub.

A good 65-inch TV (our test one) costs that much. The resolution is 3840x2160 pixels (4K Ultra HD).

In fact, UE65KS7500U TVs are hybrid, because only red and green pixels are quantum dots, and blue is LED. The reason for hybridity lies in the service life of the monitor - 30 thousand hours, and the blue quantum dot lives only 10 thousand. Therefore, it was replaced with an LED diode.

Advantages of “quantum” monitors:

energy costs are 30-50% less compared to LCD;
display brightness is 50-100 times higher;
Quantum dots are suitable for flexible panels;
due to the ultra-small dot size, the matrix has a high pixel density;
The number of light shades is 64 times more than on other Samsung TVs.

With this we will finish the physical and technical introductory part and move on to what consumers see with their eyes - design, management, operating system, opportunities.

Design

The TV screen is curved so that the viewer can plunge deeper into the picture before his eyes.

A couple of years ago, Samsung was aiming for thin, invisible bezels. Then he returned them. Apparently, they are technologically important, either for creating stiffeners or for placing electronics at the edges. Still, few people pay attention to the frames.

The steel-colored perimeter flows elegantly into a monolithic stand with legs. The weight of the stand is 0.5 kg, the weight of the TV is 23.2 kg.

Ports and connectors

On the TV body there are:
– USB
– LAN
– CI/PCMCIA
– Ex-Link

Few? Samsung supplies TVs with an external One Connect hub for those who lack built-in ports.

Additionally we get:
– 2 antenna connectors (cable and satellite)
– 4 HDMI 2.0a
– 2 USB
– optical audio output.

Image quality

Samsung's immersive effect is created by the Auto Depth Enhancer, which increases the contrast of foreground objects relative to the background.

Coating Ultra Black reduces glare on the screen. Not completely, but noticeable to the eye.

The entire 7-series KS7500 is a powerful picture enhancer. If video Low quality, then it is converted on the fly to SUHD format. If the picture has low contrast, then the technology Precision Black regulates the flow of light, causing the image to come to life. The TV plays popular video formats (avi, mkv, mov, etc.).

4 settings are responsible for gamma and color gamut: dynamic, standard, normal, cinema.

The only thing that was disappointing: the TV couldn’t cope with the complex fractal structure of Emma Stone’s blouse from the interview below. It turned out that the jacket lived its own life and with a second’s delay moved behind the actress.

I played with the Automotion Plus setting, but the strange effect persisted.

Control

Smart TV is controlled from an elegant remote control. It is minimalistic, like Apple TV, and at the same time more functional. It has buttons hidden under the top cover, and only the main ones are made physical, such as volume and channel switching. The remote control is not touch sensitive.

The KS7500's controls are intuitive. The fact that there are practically no manipulators on the remote control does not prevent you from getting to required function. The only thing is that you stumble when entering characters in the movie search. The remote control is equipped with a microphone for voice input commands, but this feature suddenly turned off. The Korean voice recognition server probably crashed during the test.

Tizen OS

The Tizen operating system on which the TV runs is good for everyone, except for its reluctance third party developers port applications to it. The main providers of media content are built into the shell. Additionally, online cinemas ivi, Okko, Megogo are installed from the store. Consider that there are no games - only two (El Dorado casino and Monkey Madness arcade). Maybe this is for the best: if you want to play, buy a separate console.

Tizen is better optimized for TV and works faster than Android. You can feel it. The hardware is controlled by a 4-core Quad Core processor.

Conclusion

If we ignore the small number of applications and games, the Samsung SUHD 4K Curved Smart TV 65 KS7500 7 Series does an excellent job main task– convey to the owner a clear and live image. Powerful processor and a set of various technologies stretch low-quality video to the 4K level. The screen's quality reserve will last for several years to come.