Types, types and disadvantages of LED backlighting of screens. What is an LED TV

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Every person, when choosing a TV for himself, learns about latest achievements science, gets acquainted with new technologies and terms. One of the modern technologies in the field of television is LED. In reality, an LED TV is an ordinary liquid crystal LCD TV. This means that the image in it is formed using a matrix consisting of pixels.

If in older devices the backlight was a fluorescent lamp, then in LED models the backlight is a matrix consisting of a set of LEDs (Light Emitting Diode).

Light Emitting Diode is translated as “light emitting diode”. The scope of their application is extensive: these are car headlights, traffic lights, lamps, spotlights, street and home lamps. In a TV, light from LEDs is directed onto the LCD screen, illuminating the image.

Of course, it would be more logical to call these models LCD TVs with LED backlighting. However, Samsung, which is a pioneer in this field, called these models "LED TV". The term became popular and began to denote a class of new televisions. The LEDs in these TV receivers do not form a picture as a real unit (pixel). Therefore, LED TVs cannot be considered full-fledged LED models.

How LED lighting works

To understand the operating principles and features of this device, you need to become familiar with the types of backlighting on a TV. Currently, several lighting systems have been developed. They differ from each other in their location and color.

Color of glow sources

Single color system (White led) more energy efficient fluorescent lamps, but still considered budget option. LEDs do not contain mercury, like lamps, but in terms of color rendering and coverage depth, LED TVs with this backlight are practically no different from LCDs.

Multi-color system (RGB) compares favorably with the previous version. TVs with this backlight have a wide color palette. Accordingly, very good color rendition. Unfortunately, this effect comes at a higher price. To operate such models, you need a modern, powerful graphics processor. These TVs consume more electricity and have a more bulky body, comparatively speaking, of course. The cost of these TVs limits demand, so leading companies are gradually abandoning RGB backlighting and are looking towards analog household appliances.

Mixed backlight option (QD VIsion) uses only blue LEDs and special films. The film is a collection of quantum dots that have red and green colors. This allows you to have a tuned spectrum of optical waves, limited in range. For this account color palette expands and brightness and intensity improves. Unlike the RGB system, this technology is more energy efficient.

The answer to the question of which backlight option to use is ambiguous. There are still various controversial opinions and discussions on this matter. Toshiba believes that white backlighting, based on all its characteristics, is preferable to RGB.

Accommodation options

There are two options for placing the backlight:

General advantages of LED TVs

These devices are an undoubted step forward in the development of television. They enjoy deserved popularity in everyday life. There are several main advantages:

Manufacturers are constantly working to improve these panels. The new technology is called OLED TV. In these TVs, the backlight is organized using organic light-emitting diodes. They are characterized by an even thinner body and improved color rendering.

Speaking about LED technologies, we should not forget that in the manufacture of LED TVs they do not use, as before, harmful substances - mercury and aerosols.

Some LED-TV models use “local dimming” technology. It is designed for local dimming. The basic idea is to control groups of LEDs. Each group contains several elements. True, with this approach, bright spots sometimes appear in certain areas of the screen in those areas where the backlight is turned on at full power. And where the backlight is not used, dark spots may appear.

Screen resolution. Determined by the number of pixels that form the image in width and height. The higher this parameter, the clearer the image and the more different details you can see on the screen.

LED-TVs mainly have Full HD (1980×1920 pixels) and H.D. Ready (1366×768 pixels) resolution. These are the most popular formats video in currently. Some premium models have 4K UHD resolution (3840x2160 pixels).

Almost all 4K UHD TVs support HDR. This is an extended format dynamic range, which allows you to depict a picture as close to reality as possible.

Screen coating. There are matte and glossy. At matte finish the image is softer. Viewing angle is limited. When hit sunlight no glare. If the coating is glossy, then the picture on the screen is very bright and contrasting. Visibility becomes poorer in bright sunlight.

Functional connectors. Usually there are standard ones: HDMI output, Ethernet output and USB connector for watching video from a flash drive or hard media. IN latest models there is a D-sub video port. It involves connecting a computer to a TV.

Sweep frequency. An indicator of how many frames of a film are shown per second. It is measured in Hertz and can reach values up to 960 Hz. For 3D TVs, the frequency can be even higher. The recommended range of values so that the image does not blur and pictures do not overlap one another is 100−200 Hz.

Additional features

DVB-T. Standard digital television. Allows, in addition to analog cable and terrestrial television, connect satellite.

Volumetric 3D image. Using this option, you can view 3D images with active or passive 3D. It is necessary to take care of special glasses.

Smart TV. Allows you to connect and use the Internet. Connection occurs via WiFi module. Connection possible via network cable. Some TVs allow you to build in an additional router. With Smart T.V. you can play videos from the Internet, play, listen to music, and search for information.

LED devices have become popular. After all, LED TV - what does it mean? This high quality, convenience and comfort of use. The advantage of an LCD TV is LED backlighting; all LED models have it. But for design features, additional features sometimes you have to pay extra. What should you pay attention to when choosing an LED TV model?

First of all, you need to decide which diagonal is best to choose. Available in stores huge selection different models from 19 to 58 inches. Sometimes it’s not very common to calculate in inches and you have to select the size in centimeters, that is, from 48 to 147 cm. Right choice diagonal depends on the size of the room where the TV will be installed.

There is an approximate table of the ratio of diagonal and distance to comfortable viewing.

These data are approximate and allow adjustments within half a meter.

14−17 inches - from 1.5 to 2 m.
21−25 inches - from 2 to 3 m.
26−32 inches - from 3 to 4 m.
34−37 inches - from 4 to 5 m.
42−55 inches - from 5 to 7 m.
61−80 inches - from 7 to 10 m.

So, when choosing a TV, you need to think about its location in the room in advance and select optimal model, based on the layout.

After choosing the TV diagonal, you need to consider the resolution. Here the criterion is the larger the better. Full HD will provide complete comfort and satisfaction from your TV.

The quality of the picture is assessed subjectively. If possible, colors should be natural, without overexposed areas or spots. The image during fast movement should not be jerky, but smooth. The black color must be free of impurities, as black as possible. You should check the transmission of halftones to see if the details are different. The color of the human body: hands, face should be pleasant, without yellow or red spots.

Manufacturers need to be well-known. In addition to the guarantee, this also includes service, as well as the availability of various additional parts and accessories in stores and service centers.

And of course you need to think about additional functions. Do you need Internet access or how important is it to connect your laptop to a large screen?

What is the difference between an LCD and an LED TV?

LED technologies are gradually replacing liquid crystal technologies, since the former are more efficient and economical. This is a serious energy saving and best picture on the screen. Although the differences between these LCD and LED approaches lie only in the way the screen itself is illuminated.

Everything is moving forward. Modern films are produced for latest technologies. Therefore, in order to fully immerse yourself in the atmosphere of the new film, it is better to watch it on LED-TV.

Today, devices with LED backlighting - The best decision in terms of image quality and equipment cost. Modern solutions in televisions of this type allow them to compete with expensive plasmas(PDP), confidently displacing the latter from the market.

True OLED TVs are very promising. In these panels, LEDs are truly the imaging unit. But these models are still expensive and only pay for themselves with very large screen sizes.

Attention, TODAY only!

Models of LED-backlit TVs dominate the market and deservedly so. In this article we will look at the types of LED backlights 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 O LED TV ov, which are manufactured on the basis of emitting technologies, where each pixel is a separate light source; in liquid crystal models, each pixel LCD matrices 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 backlighting using CCFL lamps. But to change the thickness of TVs downward, the developers abandoned the use of a full array of LEDs behind the screen, installing lines of light sources 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. Model data LCD TVs 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 turn it off completely separate groups 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 negative– the effect of local haze, which is formed when part of the light from brighter zones leaks into neighboring darker ones, which subsequently lightens the dark color at the border. 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.

Using standard backlight With the use of CCFL lamps and in most LCD TVs with edge LED backlighting, all backlight sources brighten or dim at the same time (the so-called " global dimming"), but among the models Samsung TVs and LG, displays with side LED backlighting are rare, which can also operate 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. The black level drops when using LED backlighting and possibly shifting the viewing angle by 1-2 meters to the left or right.

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 applied. 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 backlighting (Edge LED) built into the frame of the TV on all sides of the screen is complemented by the so-called quantum dots- fragments of a semiconductor several hundred atoms in size, emitting 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: color gamut Sony models The KDL-46W905A has coverage comparable to organic light-emitting diode (OLED) solutions and unmatched by 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 backlight 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, model 55EM9600 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 V South Korea, 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 with both flat and concave screens. Due to their extremely fast response time, such devices allow you to simultaneously demonstrate two or four programs in the format high definition(Full HD) or two various 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.

In this article we will look at what LED technology is and where it is used. I’ll say right away that not only the matrices of monitors and televisions (), but also anything from the bottom of a car to tap water are illuminated. Now let's talk about this in more detail.

Generally speaking, an LCD monitor is a device that consists of just a few basic components. This is the pixel matrix, backlight and top protective layer. In this case, the image itself is generated by a matrix of pixels, but since it does not emit light at all, it has to be illuminated from behind. You can shine a flashlight from the front, but it’s unlikely that anyone will sit and shine it into the monitor while working;) A backlight is used for this.

Previously, in older models of LCD monitors, it was electroluminescent, that is, a tube with gas, as in lamps for lighting schools, offices, and so on. It is clear that in monitors and televisions such lamps are much smaller, and the gas is different, but the main operating principle is the same. Now, most new models use LED backlighting, that is, LEDs (light-emitting diodes).

When using lamps, they are installed around the perimeter of the screen, and to distribute the light evenly from the perimeter to the center, reflectors and light-diffusing filters are used.

When using LED backlighting, two options are possible. The first is traditional, cheap and practical - the same installation around the perimeter. In this case, everything is done in the same way as with lamps - diodes are installed around the perimeter and their light is carried to the center by reflectors and various filters. But, naturally, there will be no improvement in the quality (uniformity) of illumination compared to electroluminescent lamps. But, however, there are advantages! Reducing energy consumption when using LED backlighting is reduced several times. As, in fact, the release of heat.

All of the above applies to the budget - white backlight (although it is actually blue, additional yellow filters are simply used). It is installed on the sides for the same purpose - saving money. Such monitors sell out faster because they do not scare away consumers with their prices. But there is another option for installing the backlight - over the entire surface of the matrix. It is much more uniform and of better quality, and besides, it is also colored. Yes, this is the so-called RGB LED backlight. It consists of RGB LEDs in three colors: red, green and blue. Located over the entire area of the matrix, such a backlight can be turned off to obtain an absolutely black color on the screen, or can be illuminated with a certain color, giving the picture brightness and color saturation.

However, since the cells can be quite large, when complete shutdown parts of the backlight to obtain black color, the part of the image that should be bright may also be affected. But, most likely, this will all be solved simply by increasing the number of LED cells or even control individual diodes on your own, you just need more computing power central processor at the monitor.

LED lighting throughout

In fact, backlighting can be used anywhere. For example, I have selected for you some successful, in my opinion, pictures with diodes.

LED bike lighting

Sofa with lighting

As you can see, everything depends only on imagination. LED lighting is perfect for cars, bicycles, furniture and even showers or faucets. Quite interesting effects are obtained and your hands begin to itch to do something similar, well, go ahead! Don't hold back :)

Today there are such a variety of TV models on the shelves that the consumer is simply lost and does not know what to choose. Dozens of screens before your eyes different sizes and thickness with incomprehensible words on explanatory signs. For example, if the sign indicates that the TV type is LED, what does this mean?

You know that the screens of some modern televisions are a liquid crystal matrix. If the matrix is illuminated from the inside with special LEDs, then it is an LED TV.

What is LED TV backlighting?

Edge LED

If you disassemble the TV, then behind the liquid crystal matrix along the perimeter of the case you can see many diodes that look like small light bulbs - this means that the TV has side lighting. The diffuser makes the screen illuminated evenly, but the backlight cannot be adjusted.

Matrix backlight (LED Backlight)

It is carried out by groups of diodes of three colors located over the entire surface of the panel. This method of illumination allows you to adjust it in individual areas, which allows you to achieve better color rendition.

What does LED TV mean for the consumer?

It is believed that this type of TV has a number of advantages over a conventional LCD TV.

What are the differences between LED TVs?

TVs of this type have a more contrasting image;
the colors are very rich and natural;
LED TVs consume less energy;
The LED TV body is thinner;
The TV is capable of displaying a high-definition signal;
Screen viewing angles are maximum.

TVs are equipped with a number of connectors for connecting various devices and are even able to connect to the Internet.

Characteristics of LED TVs

permission. The resolution of LED TVs can be: Full HD and HD Ready. Full HD - the most a high resolution;
sweep frequency. The scan frequency can be up to 960 Hz. More high frequency scans will be required for 3D TVs;
matte or glossy screen. The glossy finish of the screen may cause glare. On matte, the viewing angle is not so great;
. If you are going to watch 3D movies, then choose between two display technologies and two types of glasses: active and passive. Determine by viewing which type is more suitable for you, is not irritating, and is comfortable for the eyes.
smart function. Smart function will come in handy if you are going to go online. Choose a model with or without a built-in router.

So, you have made your decision and decided to purchase an LED TV. Where do we start choosing?

How to wipe LED TV?

In addition to all sorts of special liquids and wipes, which are available in abundance on store shelves, the TV is wiped with microfiber wipes. First slightly damp and immediately dry.

Using our tips, you will be able to choose the LED TV that best suits your needs and can save on features you don’t need.

Choosing suitable model TV, many consumers are faced with new terms and modern technologies. For example, not everyone knows what a TV is LED technology, and on what principle its work is based. Despite this, today this type of flat devices is most popular among buyers, so they are considered a completely familiar 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, modern led tv is a representative of 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.

Developers were the first to use this technology Samsung. 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

White led or single color system(white LEDs). Counts 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.
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 powerful GPU, 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.
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, technology, unlike RGB LEDs more energy efficient. A striking example of a mixed backlight option is the line of Bravia TV 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 developer digital technology Toshiba claims that white TV backlighting is much more efficient 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.

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.
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.

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;
Contrast and image clarity. LED TV is the main competitor of other types of TVs, as it has excellent image reproduction quality and adjustable contrast levels. 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.
Energy efficiency. Energy savings are perhaps the main point that attracts many buyers. Compared to its predecessors, the LED device consumes 40% less resources.
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 great amount models that include both classic solutions and interesting shapes and colors.
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 even more slim body, light weight (relative to its diagonal), wide viewing angle, absence of flare 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 modern LED TVs are unlikely to drop anytime soon. Detailed comparative characteristics both types are given in the article