LED TV technology - how it works. Operating principles of LED TV and LED backlight

LED backlighting of displays is one of the many ways to use LEDs. It has been used on an industrial scale since 2008. Today, LEDs are installed in the vast majority of liquid crystal (LCD) screens: televisions, monitors, mobile devices.

Since 2008, LED backlighting has been actively improved and improved. In this article we’ll talk about what LED backlighting is, what it comes in, and how justified its implementation in electronics is.

A little theory

Just 10 years ago, the main light source in LCD screens were CCFL and HCFL fluorescent lamps, which were inferior to plasma TVs in image quality. The advent of white SMD light-emitting diodes with high luminous efficiency, low power consumption and dimensions has radically changed the situation, thanks to which a new generation of monitors has appeared.

Stores began to actively offer LED TV, without explaining that only LED backlighting was used, and the screen still remained liquid crystal. Large-scale advertising campaigns and beautiful stories from consultants about the advantages of the LED option have contributed to a sharp increase in sales of LED TVs and monitors, thanks to which today they have complete superiority over other types of backlighting.

Types of LED backlight

With the invention of compact ultra-bright LEDs, manufacturers were faced with the question: “How to place them in order to simultaneously obtain a high-quality image and save money?” Several types have appeared in search of an answer LED backlight, among which there are two main ones:

• end (Edge), also called side or edge;
• matrix (Direct), assembled on wled or rgb led.

According to the method of controlling the glow, there are also two types of backlight: static and dynamic. In the first case, the brightness of all LEDs changes equally regardless of the image. In the second case, each LED or group individually interacts with the corresponding section of the LCD matrix.

Edge

LEDs in the side lighting are arranged in one of the following ways:

• on the sides;
• above and below;
• along the perimeter.

The choice of one or another placement method depends on the screen size and production technology. This type of backlight uses only white LEDs. The light flux they emit passes through the diffuser and the light guide system, thus illuminating the entire screen.

This method has three important advantages that made it popular. Low cost achieved due to the minimum number of LEDs used and the simplicity of the control system. The ability to create ultra-thin monitor models with a remote power supply, which, due to advertising, have become very popular among buyers. Low energy consumption, which is impossible to achieve in other variations. In terms of light characteristics, edge backlighting occupies an average position and strongly depends on the build quality and the used element base. But in general, color rendition is comparable to CCFL technology. Edge-lit TV models cannot achieve high contrast images for two reasons. All LEDs shine with the same brightness, equally illuminating dark and light areas of the screen. Light guides, despite their well-thought-out design, are not able to ensure uniform distribution of light over the entire working surface.

Direct

The back (matrix) illumination is a matrix assembled from several lines with LEDs distributed over the entire area. This method ensures uniform illumination of the entire LCD panel, and most importantly allows for dynamic control. As a result, the developers managed to achieve high image contrast and rich black color.

Direct backlighting is implemented in two ways. The first, most common, is assembled using white LEDs or WLEDs, which are basically the same thing. It can be either static or dynamic, depending on the TV model.

The second involves using RGB LEDs instead of white ones. With their help, it is possible to adjust not only the brightness, but also set any color from the entire visible spectrum. Due to the high switching speed, the LEDs perfectly process the supplied signal and keep up with the rapidly changing picture on the screen. RGB lighting is built only according to the dynamic principle.

Matrix-backlit displays feature excellent contrast and color rendition across the entire screen area. This is their main advantage, which is covered by several disadvantages, namely:

• high cost;
• high power consumption comparable to CCFL technology;
• The case thickness is more than one inch.

If one of the LEDs fails, the entire line goes out. This phenomenon will be reflected on the screen as a darkening of a certain area. It will not be possible to replace a burnt-out element with a similar one on your own, since it is almost impossible to find an exact copy with the same lens. As a result, the entire line must be replaced.

About health disadvantages

LED backlight itself, regardless of its implementation method, has several significant drawbacks that affect not the image quality, but the vision. First of all, this is a pulse-width modulation function. With its help, the user adjusts the brightness and, thereby, worsens his health. The essence of the problem is the flickering of LEDs with a frequency above 80 Hz, which manifests itself when the brightness is reduced. Such flickering is not visually detected by the human eye, but it continuously irritates the nerve endings, causing headaches and fatigue in the eyes.

While watching television, this disadvantage does not cause much discomfort due to the large distance between the viewer and the screen, as well as low concentration. But users of PCs and laptops with LED backlighting find themselves in a dead end situation. On the one hand, when the monitor brightness is 100%, the pulse width modulation (PWM) function is disabled, but the retina of the eye suffers greatly. On the other side, long work with documents at reduced brightness it is more comfortable for the eyes, but now PWM adds negativity.

In addition, there are other shortcomings that impair vision, the manifestation of which to one degree or another depends on the display production technology. For example, increased radiation of LEDs in the region close to the ultraviolet spectrum.

Those who value their eyesight should opt for a professional series of monitors with CCFL lamps, which are still produced for working with images. They have a high color rendering index and cost less than RGB LED products.

Despite the presence of shortcomings, manufacturers of electronic equipment will not stop using LED backlighting in their devices, and large companies So-called LED TV will continue to be advertised. Because marketing goals still have a high priority. We can only hope that in the near future, mass-produced monitors will be equipped with higher-quality backlighting that operates at a frequency that is safe for the eyes.

Read also

Choosing suitable model TV, many consumers are faced with new terms and modern technologies. For example, not everyone knows what a TV with LED technology is and what principle its operation is based on. Despite this, today this type of flat devices is most popular among buyers, so they are considered a completely common attribute in the home. Before you do it, you should still figure out what the abbreviation LED means, how such TVs differ, and what advantages they have over other types of TV.

If translated literally, then LED – light emitting diode. However, it is advisable to believe that it cannot serve as a complete definition. In fact, a modern LED TV is a representative of the long-known liquid crystal panels. The main component is an LCD matrix with many luminous dots - pixels. But if the usual LCD devices used fluorescent lamps as backlight, then the devices in question use LEDs, that is, TVs with such backlighting are more advanced options LCD-models.

Samsung developers were the first to use this technology. As a marketing ploy, the new TVs were given the name LED TV, which is still used today.

LEDs here act as light sources, and are not the actual unit of the image being formed. Therefore, it would be more correct to call such panels LCD TV with modern LED backlighting.

Types of LED backlight

In order to understand what the fundamental feature of such equipment is, you need to understand the types of TV backlighting. Today, several systems are used; they differ in color and arrangement.

By color of light sources

1. White led or single color system(white LEDs). It is considered a budget solution, but still outperforms fluorescent lamps. LEDs are more energy efficient and do not contain mercury. As for color rendering and coverage depth, LED TVs with this type of backlight are not much different from LCDs; the difference is more significant in the next option.
2. RGB or multi-color system. Their color palette is much wider. Due to this, color rendition improves. But it is worth noting that models with a similar backlight option are more expensive, which is not commensurate with the achieved effect. Such models require a powerful graphics processor, and they consume more electricity. Since such HDTVs are not affordable for every group of consumers, leading companies decide to abandon RGB backlighting and continue to search for analog technology.
3. QD Vision or mixed backlight option. It is based on pure blue LEDs and a special film with quantum dots, which have green and red colors. This technology makes it possible to emit a strictly limited and tuned spectrum of optical waves. Due to this, the color palette and intensity of colors expands, at the same time, the technology, unlike RGB LEDs, is more energy efficient. A striking example of a mixed backlight option is the line of Bravia television panels, the leading manufacturer of Triluminos Sony.

In fact, the question of using the first and second backlight options continues to find many controversial opinions. For example, the famous digital technology developer Toshiba claims that white TV backlighting is much more effective than RGB. So why spend a ton of money when you can save millions?

According to the lighting placement option

There are 2 options here.

1. Along the perimeter of the LCD matrix(Edge LED). This is a one-color system (White led), which can be located on one side (most often from the bottom), on parallel sides (on the sides) or along the entire perimeter. The method of organizing side lighting depends on the size of the screen diagonal. The disadvantages of such backlighting include “flares” at the edges of the TV screen and an insufficient level of contrast (compared to the second type). But this technology makes it possible to create panels only a few millimeters thick.
2. Directly behind the LCD matrix (Direct LED). It is based on the uniform distribution of diodes over the entire area. In terms of price, it is more expensive than edge lighting. The main advantage of such a system is the ability to use local black dimming technology. Both white and color LEDs can be used here; they significantly improve image quality.

If you already own such a TV and have problems with the image, you may find information about

Advantages of LED TVs

These panels have significant advantages, which is why they are popular among consumers. Of the main advantages, the following factors should be noted.

1. Case thickness. It is through the use of LEDs that the production of ultra-thin models has become possible. This TV can be easily mounted on the wall using a bracket;
2. Contrast and image clarity. LED TV is the main competitor to other types of TVs because it has excellent quality image reproduction, adjusting the contrast level. Remembering when problems with the perception of moving objects were observed, it can be noted that with modern ice screens such problems will not arise.
3. Energy efficiency. Energy savings are perhaps the main point that attracts many buyers. Compared to its predecessors, the LED device consumes 40% less resources.
4. Wide range of models not only in functionality, but also in appearance. Such a panel will decorate absolutely any interior without any problems. Leading manufacturers have a huge number of models, including both classic solutions and interesting shapes and colors.
5. Durability. Thanks to the use of fade-resistant LEDs, TVs have more long term operation.

But the improvement of such television panels does not end there. Already appearing on store shelves todayOLEDTV, the illumination of which is based on organic light-emitting diodes. They have an even thinner body, low weight (relative to their diagonal), wide angle visibility, absence of “lights” and glare, excellent color rendition. However, this does not mean that other lower class models will lose demand. Innovative technologies This format is not cheap, and the financial capabilities of most consumers will not allow them to have such a widescreen panel at home. Therefore, the demand for simple models of modern LED TVs is unlikely to fall in the near future. Detailed comparative characteristics of both types are given in the article

L

If you want to enjoy watching your favorite movies, TV series and TV shows in the evenings, then you just need to buy a good LED TV. Nowadays, equipment manufacturers offer a huge number of such devices at different prices. Find out what an LED TV is. These TV panels have a huge number of advantages and will delight their owners with high-quality, bright images.

What are LED TVs

An LED TV is a device that is a TV receiver with a liquid crystal screen. The matrix is ​​equipped with a special backlight from a set of LEDs. Explanation of the abbreviation LED - “Light Emitting Diode”. From a technical point of view, it would be more correct to call such devices liquid crystal with LED backlighting. However, Samsung was the first to launch such a device on the market under the name “LED TV”. Other manufacturers adopted it, so it became common.

LED backlight

Now releasing different types such devices. They differ in the type of LEDs used and the order of their location in relation to the screen. By lamp color:

1. Single color (White LED). Budget option. It does not have the disadvantages of fluorescent backlighting and creates an image with a similar color gamut, but not as contrasty.
2. Multi-colored (basic RGB LED color triad). The color palette is expanded due to the LED brightness control. The number of semitones has been increased. To support this technology you need a powerful GPU. The model will cost more and consume more energy.
3. Mixed. Blue LED backlights and a special film with green and red quantum dots. This technology reduces the device's power consumption.

We found out what LED backlighting is on a TV. In addition to the color of the lamps, it differs in their location. There are two options:

1. Directly behind the LCD matrix. Direct backlight type Full or Direct LED. These models are cheaper than Edge, but not as thin. With a high level of contrast. They have white and multi-colored LEDs.
2. Along the perimeter of the LCD matrix. Edge LED backlight type. LEDs can be located on one (bottom), two (side) or four sides of the screen. Thanks to this, manufacturers produce models less than 1 cm thick in these LED devices white. Budget models made using this technology have a drawback. They show highlights along the edges of the screen. In addition, they have a low contrast level.

Characteristics

There is a huge variety of models from different manufacturers on the market. They differ in price depending on the parameters they have. To make it easier to choose a model based on your budget when purchasing, learn to understand at least the key characteristics that an LED TV has:

1. Permission. There are several options: Full HD, HD Ready, Ultra HD. The latter is considered the best.
2. Smart function. Thanks to this option, you can access the Internet directly from the device. There are models with and without a built-in router.
3. Sweep frequency. Shows how many times the image is updated per unit of time.
4. 3D image function. If you plan to watch films in this format, then choose from two display technology options: active and passive. Compare both options in the store and determine which is more comfortable for your eyes.
5. Matte or glossy screen. The first one does not have such a large viewing angle, but the second one has glare.

Advantages

An LED TV is nothing more than an LCD screen, but improved. LCDs used to use CCFL cold cathode fluorescent lamps as the light source. They were replaced with LED lighting. This freed liquid crystal devices from their characteristic disadvantages. Thanks to LED technology, TVs have become thinner (especially Edge models). They are environmentally cleaner and more energy efficient, do not contain mercury, and do not require specialized disposal. Advantages:

• more contrast image compared to other technologies;
• maximum screen viewing angles;
• rich and natural colors;
• consumption of a relatively small amount of energy;
• display high definition signals;
• thin body.

LED TVs

There is a huge range of panels from different manufacturers on sale. You can easily choose a small budget device or a huge one with many additional functions and capabilities. Some panels can be used not only for watching movies, but also for playing games on the console. Find out which models from well-known manufacturers are the most popular.

Shivaki

• Model name: Shivaki STV-48LED15;
• price: 24,000 rubles;
• characteristics: black, screen diagonal - 48 inches (121 cm), refresh rate - 50 Hz, resolution 1920x1080 dpi, video in Full HD format, sound power - 16 W, four digital tuners, 3 HDMI ports, 1 USB connector for viewing multimedia files from external media, there is a recording function, a child lock option, weight – 11.5 kg;
• pros: fits well into any design, can be placed on a shelf or mounted on a wall, reasonable cost, high-quality image;
• cons: no Smart TV, Wi-Fi, 3D capabilities, surround sound, few functions, poor response to the remote control remote control, inconvenient menu.

TCL

This company has a lot of TV options: plasma, LCD, LED. They are distinguished by good quality and affordable prices. You may be interested in the following option, budget but worthy:

• Model name: TCL LED32D2930;
• price: 14500 rub.;
• characteristics: diagonal 32 inches (81.3 cm), resolution 1366x768 Pixels, brightness 240 cd/sq. m, 16:9 format, progressive scan, 60 Hz refresh rate, Smart TV, timers, child lock, teletext, program guide, 2 built-in speakers, stereo sound power 10 W, surround sound, Wi-Fi? connectors – component, 3 HDMI, PC input, coaxial audio output, 1 USB, black;
• pros: cheap, can be hung on the wall or put on display, good picture and sound quality, bright colors;
• Cons: too fragile, cannot be used instead of a monitor.

Samsung

The company's products include a huge number of LED TVs. Nowadays this one is especially popular:

• Model name: Samsung UE40MU6100UXRU;
• price: 36,000 rub.;
• characteristics: diagonal 40 inches (101.6 cm), Edge LED backlight, 16:9 format, Ultra HD, resolution 3840x2160 pixels, HDR support, Smart TV, voice control, timers, program list, channel name entry, protection from children, Russian menu, program guide, teletext, digital noise reduction, comb filter, image and sound enhancement technologies, decoder with automatic and manual setting, 2 built-in speakers, sound power 20 W, 3 HDMI connectors, 2 USB ports, Wi-Fi, Bluetooth;
• pros: natural colors, stylish design, the remote control is universal and controls all devices connected to the LED TV, connects to a mobile device, excellent picture quality;
• cons: slows down when playing very large files.

LG

All LED TVs from this company are different high quality, durability and attractive modern design. This option will fit perfectly into a stylish interior:

• model name: Ultra HD (4K) LG 43UH619V;
• price: 32,000 rub.;
• characteristics: white, diagonal 43 inches (109.2 cm), Direct LED backlight, 16:9 format, Ultra HD available, resolution 3849x2160 pixels, progressive scan, anti-glare coating, Smart TV, input of channel names, child lock, menu Russified, teletext, program guide, Plug&Play function, dynamic scenes index, digital noise reduction, comb filter, 2 built-in speakers, sound power 10 W, surround sound, 3 HDMI port, 1 USB connector, Wi-Fi;
• pros: good image detail, detailed clear instructions, loud and clear sound, a lot of useful functions and modes;
• disadvantages: there is distortion of the picture when viewed from different angles, there are few applications, you often need to adjust the screen format to the files different types, inconvenient wall mounting.

Mystery

Among the wide range of this manufacturer there are a lot of inexpensive and high-quality models. Pay attention to this option:

• model name: Mystery MTV-4030LT2;
• price: 18,000 rub.;
• characteristics: diagonal 40 inches (101.6 cm), Direct LED backlight, 16:9 format, Full HD, resolution 1920x1080 pixels, progressive scan, refresh rate 60 Hz, timers, clock, input of channel names, program list, protection against children, freeze frame, Russian menu, blue screen, shutdown when there is no signal, teletext, program guide, built-in radio, digital noise reduction, 2 tuners, 2 built-in speakers, power 20 W, 3 HDMI connectors, 1 USB port;
• pros: affordable price, convenient menu;
• cons: not very saturated colors, insensitive remote control, no Wi-Fi, poor sound.

How to choose an LED TV

Buying equipment for your home is a very important moment that needs to be approached with the utmost seriousness. It is important to go to stores with a good reputation that guarantee the quality of their products. You can either buy an LED TV or order it from an online store with delivery from Moscow or St. Petersburg to your home by mail. It is profitable to buy equipment before the holidays; during such periods, stores often have sales and promotions and offer excellent discounts. Tips for choosing an LED TV:

1. Screen diagonal. This is one of the most important indicators. Many people think that bigger screen- so much the better. Optimal size should be calculated as follows: divide the estimated distance from the viewing location to the LED TV by three. The diagonal should be equal to the number you get.
2. Screen resolution. The best for today, but also the most expensive, will be an Ultra HD LED TV.
3. Image quality. This option should be selected based on personal preferences. In stores, as a rule, there are a lot of working TVs broadcasting the same file. Compare which one you like better.
4. Screen covering. Glossy is more contrasty and brighter. However, it is not suitable for a room with a lot of sun, it will glare. Matte makes the image less clear, but is not shiny at all.
5. Format. The most popular at the moment is 16:9. Suitable for watching both digital and satellite television. The second 4:3 format option is suitable for cable channels.
6. Manufacturer. Buy only products from companies that have been on the market for a long time and have proven themselves well. Pay attention to reviews online.
7. Settings. The more options you can adjust, the better. On some budget models It is impossible to even change the brightness of the image.
8. Additional features. Modern LED TVs are equipped with many options that are not critical: voice control, wi-fi, built-in router. Assess your budget and decide which bells and whistles you need.
9. A set of functional connectors. It is better to purchase a TV that has HDMI and USB ports for connecting other devices. Check whether the connectors are conveniently located and whether access to them will be difficult.

Video

Quite recently - in the midst of summer, a report was published on our website Samsung LED TVs: from Kaluga with love, dedicated to the opening of the Russian Samsung plant for the production of various electronics and household appliances - Samsung Electronics Rus Kaluga (SERK). Let me remind you: the key point of the report was the story about the launch production lines for the production of the most modern and most relevant flat panel panels today Samsung TVs with LED backlighting - the so-called LED TV. Since then, the editorial mail has received more than once letters in which our readers ask us to tell more about LED technology TV. The main questions lie in the technical details of the technology, its advantages over competing proposals, and so on. But almost always we are talking about the price factor: is it really worth paying for an LED TV an amount that is sometimes more than twice the cost of an LCD and plasma TVs with similar diagonals and screen resolution, will there be a real return on such costs? What is typical is that as time passes, the relevance of the questions asked does not decrease. Flat panel TVs are becoming fashionable, and their range is constantly expanding. You don’t have to look far for an example: the Kaluga plant of Samsung Electronics plans to produce about 75 thousand televisions of all three LED TV series - 6000, 7000 and 8000, with diagonals of 32, 37, 40, 46 and 55 inches by the end of the year and with special emphasis on the most popular are 32- and 40-inch models. Already now, these models are present on the shelves of most Russian retail chains, along with this, the choice of “LED” TV models from other companies is growing, so the growing interest in this technology is quite understandable. In short, today we are publishing a brief overview of the features of the production technology of flat panel displays with LED backlighting.

LED TV or LED LCD TV?

LED TV vs CCFL LCD TV

LED backlighting varies

However, further we will look at LED TV technology using the example of Samsung Electronics TVs - for the reason that currently in Russia Samsung’s share of the LED TV market reaches 98%.

Samsung LED backlighting: how it works

At its core, an LCD screen is a multilayer “pie” made up of color filters, liquid crystal arrays, backlight lamps, etc. The liquid crystal cells themselves do not glow, but, depending on the voltage level applied to them, they open to allow light to pass through fully, partially open, or simply closed when a dark area of ​​the picture is displayed.

The role of the backlight lamps in this whole story is to illuminate the slightly opened LCD cells so that the final picture appears on the screen. Despite such a simplified retelling of the operating principle of the LCD display, this is quite enough to understand the purpose of its main components. The thickness of the layers of the “pie” of different LCD screens is different. When using traditional fluorescent lamps, the backlight layer is so thick that it occupies more volume than all other layers combined.

Let's replace the fluorescent lamps backlighting the LCD cells with LEDs. The first obvious effect of such a replacement is a significant reduction in the overall thickness of the LCD panel. Moreover, in Samsung LED TVs, the LEDs are placed not behind the matrix, but along its edges, due to which the presence of such an end layer has practically no effect on the overall thickness, but the overall weight is significantly reduced.

The LED BLU light-directing layer ensures uniform illumination in all areas of the screen. Thanks to a special reflective grille, the light transmission efficiency of Samsung LED TVs is stated to be 20% higher than that of models with direct RGB LED backlighting. In addition, instead of the usual 10 or more centimeters in thickness, it turns out to be less than 3 cm - if you want, put such a TV on a shelf, or if you want, hang it like a picture on the wall using a specially designed lightweight mounting system. The thickness of Samsung 8000 series LED TVs is 11 mm in the thinnest part of the body, and 29.9 mm in the thickest part. In advertising, Samsung always indicates the value obtained by measuring the thickest part of the case.

For reference: Samsung 8000 series LED TVs use 324 LEDs for backlighting. Thanks to the complete elimination of fluorescent lamps, LED TVs do not contain a single gram of mercury. IN Samsung technology in addition to this, it was also possible to completely get rid of soldering using lead compounds, and to practically reduce emissions of volatile organics and other harmful by-products by eliminating the use of sprayed powder paints - the thin, durable and attractive casing of the new TVs is made using special technology Casting Crystal Design. Another significant advantage of LED TVs is the high level of image contrast, which significantly exceeds the best performance of traditional LCD matrices. The brightness of the LEDs is so high that, for example, in Samsung LED TVs of the 6000, 7000 and 8000 series, the contrast ratio reaches 1,000,000:1. In addition digital processing signal with Mega Dynamic Contrast technology provides a detailed image in low-contrast “twilight” areas of the picture.

The maximum capabilities of the new backlight system are squeezed out using a multi-layer Ultra Clear Panel filter, which transmits light from inside the screen and does not reflect it from the outside, so it is possible to achieve better brightness and contrast with a minimum of glare, regardless of how the screen is lit from the outside - sunlight or artificial electric lighting. LED backlight allows you to achieve white illumination of LCD cells, as a result of which it is possible to display a wider and more natural range of color shades. The color palette of LED TVs turns out to be richer and more saturated, with green and blue bright areas compared to conventional models no longer look faded and pale. In Samsung LED TVs, color saturation is also additionally monitored by the Wide Color Enhancer Pro hardware technology. Often, the weak point of LCD screens is the blurred image with a long response time, which reduces the sharpness of the image and reduces the smoothness of the movement of objects in dynamic scenes. In the new Samsung LED TVs, this is monitored by the Motion Plus interpolation system: models of the 6000 and 7000 series have double the 100-Hz scan, and the flagship 8000 series have quadruple the 200 Hz scan.

An important factor is electricity consumption. Traditional LCD TVs are, of course, more economical than previous models with cathode ray picture tubes, but don’t forget that the diagonals are no longer the same, so with large LCD TVs, electricity meters still spin quite quickly. As for the new LED models, LED backlighting can significantly reduce energy consumption without sacrificing image brightness.

In addition to significant energy savings - up to 40% compared to traditional LCD models with the same diagonal, Samsung LED TVs can also boast certification according to one of the most stringent environmental standards. Energy standards Star 3.0.

LED TV Samsung: it's not just a TV...

First of all, Samsung LED TVs of the 6000, 7000 and 8000 series, along with the reception of traditional analog channels ready to work with digital TV thanks to the presence of built-in DVB-T/C tuners. Whenever the era of ubiquitous digital television arrives in Russia, you are already ready for it. In addition, the LNA plus tuner used in these models was created specifically taking into account Russian specifics - interference, vast open spaces and not the first freshness of television repeaters. In addition to this, thanks to the presence of two ports USB new TVs can be used as a photo frame for viewing photos from a flash drive, watching multimedia videos in DivX/Xvid formats, for example, from an external USB hard drive, but it won’t be enough - there is a built-in 2 GB of flash memory with pre-loaded content. The TV can be "registered" in home network with access to laptops, desktops and external data storage, and the TV remote control turns into wireless keyboard to navigate through folders, display content from different places networks. For Internet access there is a LAN connector and support for Internet@TV with access to YouTube. The sound system in ultra-thin LED TVs is on par with the best Samsung models. A unique flat subwoofer was created especially for ultra-thin LED TVs, plus well-proven hidden speakers are used.

Finally, communication with consumer electronics DVD player, Blu-ray player, AV receiver, cinema, HD video camera, game console, can be done using a connection via HDMI interface, of which four are provided in the design of Samsung LED models.

LED TV: are there any disadvantages?

TV models with LED backlighting dominate the market and deservedly so. In this article we will look at the types of LED backlights on modern TVs and evaluate their effectiveness.

LED TVs

Let's start with the fact that LED TV is not a new type of HDTV. . Unlike plasma and OLED TVs, which are made on the basis of emitting technologies, where each pixel is a separate light source, in liquid crystal models, each pixel of the LCD matrix requires lighting (from behind or from the side through a lens system). So LED HDTV models are the same liquid crystal (LCD or LCD) TVs, but they have a built-in light-emitting diode (LED) backlight, which replaces the standard cold cathode fluorescent lamp (abbreviated CCFL).

2 types of LED backlight according to design: matrix and side

LED backlighting with local dimming. First, televisions with LED backlight, used to illuminate the cells of the LCD matrix " full array"(full array) of LEDs, similar to standard TVs based on backlight using CCFL lamps. But to change the thickness of TVs downward, the developers abandoned the use of a full array LED LEDs behind the screen, installing the light source lines on the side of the LCD panel. Thus, the distribution of light from LED sources over the entire screen area is carried out using specially shaped LEDs. These LCD TV models are called TV with side or regional LED backlight, which still dominate today.

LED lighting with local dimming system allows you to automatically reduce the brightness or completely turn off individual groups of backlight sources. Most modern LCD TVs with LED backlighting are equipped with a full array of LED sources placed behind the LCD panel. dynamic backlight technology also called local or local dimming. Using local dimming, specific areas of the overall backlight LED array become darker or lighter depending on the brightness and color of the corresponding part of the image on the screen.

The ability to darken a specific area of ​​the screen can reduce the amount of light that passes through the closed pixels of the LCD panel, which has a positive effect on the rendering of blacks, which become darker and more realistic. Because black levels are critical to contrast, the perception of depth on black surfaces, full-color images become more vibrant and clear. Local dimming technology has the only drawback - the effect of local dimming, which is formed when part of the light from brighter zones leaks into neighboring darker ones, which subsequently brightens at the border dark color. It is quite difficult to notice the clouding effect on most models, since the disadvantage is directly related to the number of local dimming zones behind the screen, and manufacturers do not always provide such information.

When using standard backlighting using CCFL lamps and in most LCD TVs with edge LED backlighting, all backlight sources brighten or dim simultaneously (the so-called " global dimming"), but among Samsung and LG TV models there are rarely displays with side LED backlighting, which can also work on the principle of local dimming (“precision dimming” for Samsung and “LED Plus” for LG). To put it simply, this is a local dimming sham.

Thin models with side LED backlight Of course, they suffer from uneven screen illumination, but not everyone. Main feature of TVs with side LED backlighting– thin body, therefore it is difficult to ensure uniform distribution luminous flux across the entire screen plane. When purchasing a TV, play an image of the white surface on the edge-lit LED display screen to check that there are no brighter areas around the edges of the screen. Likewise, when the screen is filled with a black field, the edges should not appear lighter (gray).

It is also worth noting that LED backlighting, regardless of the type, does not improve the viewing angles of the LCD panel. Black level in use LED backlight and a possible shift in the angle of view by 1-2 meters to the left or right falls.

We must not forget about the energy efficiency of LED backlighting. Of course, the consumption of any model is significantly affected by the size of the screen and the brightness of the backlight sources. LCD TV models of both types of LED backlighting are much more energy efficient compared to plasma models.

LED backlights for LCD displays are divided into categories according to the following criteria:

• glow color: white or RGB;
• lighting uniformity: static or dynamic;
• design: matrix or side (this is described in more detail above)

RGB backlighting is used to fine-tune the light spectrum. In addition, additional compensation for changes in the emission spectrum of LEDs over time is often used. LED TVs with RGB LED backlighting light up different areas of the screen depending on the color of the image. Colored backlighting provides enhanced contrast and deep blacks, as demonstrated by many Sony LED TVs.

Edge LED: Better Color Rendering

Sony in new flagship models TVs - for example, the W905 line - uses Triluminos technology. The LED backlight (Edge LED) built into the frame of the TV on all sides of the screen is complemented by so-called quantum dots - fragments of a semiconductor several hundred atoms in size that emit light in a strictly specified range. Triluminos technology is designed to minimize color distortion and provide enhanced red and green tones. This will allow you to achieve an extremely uniform and natural image with a significantly wider color gamut. Tests of the first devices with Triluminos support did not disappoint us: the color gamut of the Sony KDL-46W905A model is comparable to that of organic light-emitting diode (OLED) solutions and is unattainable for LED-backlit LCD TVs. The W805 and W605 series devices, which also went on sale this year, do not use Triluminos, making their cost significantly lower. In the future, manufacturers will be able to completely abandon LED backlighting in favor of quantum dots.

OLED TVs: brightness and color at their best

TVs with OLED screens have already reached stores, and developers have rushed to release new models with concave displays. Last year, LG planned to introduce a 55-inch OLED TV to the market, but it only went on sale this summer. In Russia, the 55EM9600 model and its improved analogue 55EM9700 will cost the buyer 500,000 rubles. In addition, the device is sold in Europe, the USA and some other countries.

Advantages of OLED TVs: it is not a type of backlight, but a different technology

• accurate color reproduction
• greater brightness margin compared to other technologies
• high contrast compared to LCD models (another imaging technology).
• absence of an LCD matrix and LED backlight - their place was taken by a matrix made of light-emitting organic diodes.

Samsung and LG independently developed OLED TVs with concave screens (Curved OLED). This design is designed to minimize distortion at the edges of the image and increase detail. New items are still available in limited quantities in South Korea, the USA and some European countries. 55-inch Samsung model KN55S9C is priced by the manufacturer at $9,000 (300,000 rubles).

Of particular interest is also Multi-View technology, implemented in many models of OLED TVs, both flat and concave screens. Due to the extremely short response time similar devices allow you to simultaneously demonstrate two or four programs in high definition format (Full HD) or two different films in 3D format. Shutter glasses are used to separate the image. Each viewer can use the controls located on the glasses to select an individual program for viewing. At the same time, thanks to the built-in headphones, playback of the soundtrack corresponding to the film is ensured.