Benefits of LCD screen module

Benefits of LCD screen module

LCD, TFT, IPS, AMOLED, P-OLED, QLED are a partial list of display technologies that can be found in the mainstream consumer electronics market today. But what do they all mean? How does IPS differ from AMOLED, and is such a comparison true? We will tell you how they work, what advantages and disadvantages they have, and whether there is a difference between them from the point of view of the end user.


Liquid Crystal Display, that is, a liquid crystal display - it was this technology in the late 1990s that made it possible to transform monitors and televisions from comfortable beds for cats with cathode ray tubes inside harmful to humans into thin, elegant devices. She also opened the way to the creation of compact gadgets: laptops, PDAs, smartphones.

Liquid crystals are a substance that is both fluid, like a liquid, and anisotropic, like a crystal. The latter quality means that with different orientations of liquid crystal molecules, optical, electrical, and other properties change.

Smartphone screen types: an end to the confusion

Crystalline, liquid crystal, liquid: crystals change to another state of aggregation under the influence of temperature

In displays, this property of LCDs is used to regulate light conductivity: depending on the signal from the transistor, the crystals are oriented in a certain way. In front of them is a polarizer that "collects" light waves into the plane of the crystals. After that, the light goes through an RGB filter and turns red, green, or blue, respectively. Then, if not blocked by the front polarizer, it appears on the screen as a subpixel. Several of these light fluxes are connected to each other, and on the display we see a pixel of the expected color, and its combination with neighboring pixels is capable of producing a gamut of the sRGB spectrum.

Smartphone screen types: an end to the confusionLCD pixel circuit

When the display is turned on, the backlighting is provided by white LEDs located around the perimeter of the display, and is evenly distributed over the entire area thanks to a special backing. This is where the well-known "diseases" of LCD arise. For example, the light still reaches the pixels that should be black. In old and low-quality displays, "black glow" is easily distinguishable.

It happens that the crystals "get stuck", that is, they do not move even when receiving a signal from the transistor, then a "dead pixel" appears on the display. Due to the specifics of the light source, white flares can be seen at the edges of LCD monitors, and smartphones with LCD cannot be absolutely frameless, although both generations of Xiaomi Mi Mix and Essential Phone strive for this.

Smartphone screen types: an end to the confusion

Backlight and LCD backing Apple iPod Touch

However, in the specifications of devices, we are used to seeing not LCD, but mysterious TN, TFT, IPS or even Retina. Let's figure out what this means.

TN, or TN + film . In fact, Twisted nematic is a "basic" technology that involves polarizing light and twisting liquid crystals into a spiral. Such displays are inexpensive and relatively easy to manufacture, and at the dawn of their existence on the market they had the lowest response time - 16 ms - but at the same time they were characterized by low contrast and small viewing angles. Today, technologies have stepped forward a lot, and the more advanced IPS has come to replace the TN standard.

IPS (in-plane switching) . Unlike TN, the liquid crystals in the IPS-matrix do not twist into a spiral, but rotate all together in one plane parallel to the display surface. This made it possible to increase the comfortable viewing angles up to 178 ° (that is, in fact, to the maximum), significantly increase the contrast of the image, make the black color much deeper, while maintaining comparative safety for the eyes.

Smartphone screen types: an end to the confusion Smartphone screen types: an end to the confusion

The difference between TN and IPS matrices in the diagram

Smartphone screen types: an end to the confusion

A clear difference between TN (foreground) and IPS

Initially, IPS matrices had a longer response time and power consumption than TN displays, since the entire crystal array had to be rotated to transmit the signal. But over time, IPS-matrices have lost these shortcomings, in part due to the introduction of thin-film transistors.

TFT LCD. In fact, this is not a separate type of matrix, but rather a subspecies, which is characterized by the use of thin-film-transistors (TFT) as a semiconductor for each subpixel. The size of such a transistor ranges from 0.1 to 0.01 microns, making it possible to create small, high-resolution displays. All modern compact displays have such transistors, and not only in LCD, but also in AMOLED.

LCD advantages:

  • inexpensive production;
  • slight negative effect on the eyes.

Disadvantages of LCD:

  • uneconomical energy distribution;
  • "Luminous" black color.


Organic light-emitting diode, or organic light-emitting diode - roughly speaking, it is a semiconductor that emits light in the visible spectrum, if it receives a quantum of energy. It has two organic layers, enclosed in the cathode and the anode: when exposed to an electric current, emission occurs in them and, as a result, light is emitted.

Smartphone screen types: an end to the confusion

An OLED matrix consists of many such diodes. In most cases, they are red, green and blue and together make up a pixel (we will omit the subtleties of various combinations of subpixels). But simpler displays can be monochrome and based on diodes of the same color (for example, in smart bracelets).

Smartphone screen types: an end to the confusion

However, "lights" alone are not enough - a controller is required to display information correctly. And for a long time, the lack of adequate controllers did not allow the production of LED displays in their current form, since it is extremely difficult to correctly control such an array of individual miniature elements.

PMOLED . For this reason, in the first OLED displays, diodes were driven by groups. The controller in PMOLED is the so-called passive matrix (PM). It sends signals to the horizontal and vertical row of diodes, and the point of their intersection is highlighted. Only one pixel can be calculated per clock cycle, so it is impossible to get a complex picture, and even in high resolution. Because of this, manufacturers are also limited in the size of the display: a high-quality image will not come out on a screen with a diagonal of more than three inches.

AMOLED . A breakthrough in the LED display market occurred when it became possible to use thin-film transistors and capacitors to control each pixel (more precisely, a sub-pixel) individually, and not in a group. In such a system, called an active matrix (AM), one transistor is responsible for the beginning and end of the signal transmission to the capacitor, and the other for the transmission of the signal from the diode to the screen. Accordingly, if there is no signal, the diode does not light up, and the output is the deepest black color possible, because there is no glow in principle. Due to the fact that the diodes themselves, which lie almost on the surface, glow, the viewing angles of the AMOLED matrix are maximum. But when deviating from the gaze axis, the color can be distorted - go into a red, blue or green tint, or even go in RGB waves.

Such displays are distinguished by high brightness and picture contrast. Previously, this was a real problem: the first AMOLED-screens were almost always "wry-eyed", they could get tired and hurt the eyes. Some displays used pulse width modulation (PWM) to prevent dark images from fading to purple, which also proved painful to the eyes. Due to the organic origin, the diodes sometimes burned out in two to three years, especially with prolonged display of an unchanged picture.

Smartphone screen types: an end to the confusion

An example of AMOLED display burnout

However, today technologies have gone far ahead, and the listed problems have for the most part already been resolved. AMOLED displays are capable of producing natural colors without heavy eye strain, while IPS displays, on the contrary, tightened up in the area of ​​richness and contrast. In terms of energy consumption, AMOLED technology was initially about one and a half times more efficient than LCD, but according to tests of various devices, we can say that today this figure has almost leveled off.

Smartphone screen types: an end to the confusion

Even five years ago, the difference was no longer as high as in the late 2000s.

Nevertheless, AMOLED is undeniably gaining in popularity in the areas that are gaining popularity. We are talking about frameless gadgets, where LEDs are much easier to place than side-backlit liquid crystals, and curved (and, in the future, bending) displays, for which LCD technology is unsuitable in principle. But this is where a new type of OLED comes into play.

P-OLED . In fact, there is some trickery in separating these displays into a separate category. Indeed, in fact, the fundamental difference between P-OLED (or POLED, not to be confused with PMOLED) from AMOLED is one thing - the use of a plastic (plastic, P) substrate, which allows the display to bend, instead of glass. But it is more difficult and more expensive to manufacture than standard glass. By the way, AMOLED displays are much thinner than LCD due to the smaller number of "layers", and P-OLED, in turn, is thinner than AMOLED.

Smartphone screen types: an end to the confusion

All smartphones with a curved display (mainly Samsung and LG) use P-OLED. Even in the flagships of Samsung in 2017, where, according to the manufacturer, there is both Super AMOLED and Infinity Display at once. The fact is that these are marketing names that have practically nothing to do with actual production technologies. From this point of view, OLED displays are installed there, which are controlled by an active matrix of thin-film transistors and lie on a plastic substrate - that is, the same AMOLED, or P-OLED. By the way, although the display in LG V30 does not bend, it still lies on a plastic substrate.

OLED advantages:

  • high contrast and brightness;
  • deep and not energy-consuming black color;
  • the ability to use in new form factors.

Disadvantages of OLED:

  • strong effect on the eyes;
  • expensive and complex production.

Marketing moves

Retina and Super Retina . Translated from English, this word means "retina", and Steve Jobs chose him for a reason. During the presentation of the iPhone 4 in 2010, he said that the human eye is not able to distinguish between pixels if the display ppi exceeds 300. Strictly speaking, any corresponding display can be called Retina, but for obvious reasons no one except Apple uses this term. The display of the future iPhone X has been called Super Retina, although it will have an AMOLED display, and not IPS, as in the rest of the company's smartphones. In other words, the name also has nothing to do with the screen manufacturing technology.

Super AMOLED . This trademark belongs to Samsung, which produces displays both for itself and for competitors, including Apple. Initially, the main difference between Super AMOLED and just AMOLED was that the company removed the air gap between the matrix and the touch layer of the screen, that is, combined them into a single display element. As a result, when deviating from the gaze axis, the picture ceased to delaminate. Very soon the technology reached almost all smartphones, and today it is not entirely clear why "super" is better than "regular" AMOLEDs produced by the same company.

Infinity Display . Everything is quite simple here: "infinite display" means just an almost complete absence of side frames and the presence of minimal frames at the top and bottom. On the other hand, you can't imagine some ordinary frameless smartphone at the presentation - you have to name it beautifully.

Advanced technologies

Micro-LED or ILED . This technology is a logical alternative to OLEDs: it is based on inorganic (Inorganic, I) gallium nitride of a very small size. According to the assessment of experts, micro-LED will be able to compete with the usual OLED in all key parameters: the higher the contrast, the best stock of brightness, faster response time, durability, smaller size and lower power consumption in half. But, alas, such diodes are very difficult to mass produce, so the technology will not yet be able to compete with conventional solutions on the market.

However, this did not stop Sony from showing a 55-inch TV with a matrix of inorganic LEDs at CES-2012. Apple bought LuxVue, a research and development company in this area , in 2014 . And although the iPhone X uses classic AMOLED, future models may already have micro-LED matrices, which, we are assured , will increase the pixel density to 1500 ppi.

Smartphone screen types: an end to the confusion

A prototype Sony micro-LED TV called Crystal LED

Quantum Dots, or QD-LED, or QLED... This promising technology has taken a bit of everything from those already on the market. She got an internal backlight from LCD displays, but it does not "hit" into liquid crystals, but into very small crystals with a glow effect, deposited directly on the screen - quantum particles. The size of each dot depends on what color it will shine, the range is from two to six nanometers (for comparison: the thickness of a human hair is 100,000 nanometers). The result is vibrant, rich yet natural colors. TVs with such displays were first released by Sony in 2013. There are several models from Samsung on the market now. The quantum dots in them are used in the illumination layer. So far, this is a very expensive technology to manufacture: the average cost of QLED TVs is about $ 2500-3000.

Smartphone screen types: an end to the confusion

Quantum dots are produced as a microscopic powder and then sprayed onto a screen


In practice, modern LCD and AMOLED displays are becoming less and less different from each other in image quality and energy efficiency. But the future belongs to LED technologies in one form or another. Liquid crystals have already outlived their time and are kept on the market only due to their cheapness and ease of production, although high image quality is also present. Due to their structure, LCD displays are thicker than LED ones and are unpromising in terms of new curvature and bezelless trends. So their withdrawal from the market is already on the horizon, while LED technologies are confidently developing in several directions at once and, as they say, are waiting in the wings.


TFT LCD Display Modules by jwslcd

TFT LCD Display Modules by Jwslcd

Long gone are the days when the whole variety of monitors was limited to cathode ray tubes. Users can choose monitors that render images using a wide variety of technologies. They make it possible to create both universal and highly specialized models. This article will focus on the technology, without which it is impossible to display an image in any of the monitors produced today. This is a TFT display.

Working principle of TFT LCD display

TFT LCD display

Before diving into the intricacies of a TFT screen, we note that displays are composed of two main technologies. The first is the LCD, and the second is the matrix itself. The two elements are connected together, performing a common function - displaying an image. The two values ​​should not be related to one another. So, a TFT matrix can have any kind of backlight - LCD, LED and their variations. Likewise, one kind of backlight can be combined with different matrices. Both the backlight and the matrix have their own list of technical characteristics for which they are responsible. However, the main parameter in determining the purpose of the monitor is precisely the matrix.

In order not to confuse LCD with TFT, let's decipher what each abbreviation means. In addition, it will be useful to understand how these technologies work.

What is LCD

LCD is a technology for manufacturing monitors, familiar to us by the abbreviation LCD (liquid crystal). Liquid crystals are a special substance that can change their properties when exposed to electricity. More precisely, the changes in them are caused by electromagnetic waves. The type of this surface affects the quality of the backlight and other functions. Screens are called liquid crystal screens, because in the switched on state the substance exhibits the properties of crystals (in terms of affecting the image).

What is TFT display

The second part of the monitor is a matrix. In our case, we are talking about TFT. The name stands for Thin Film Transistor. The matrix consists of thin film transistors. Its applicability is wide - calculators, arduino displays, old and not so phones, as well as monitors for laptops and PCs.

At the time when LCD monitors were just starting to go on sale, they were equipped with so-called passive matrices. These elements were quite sluggish, since the voltage had to change on it to change the pixel value. Due to the physical characteristics of the pixels, this was slow. Consequently, those monitors had low refresh rates and were often annoying with a flickering screen.

All monitors now produced are equipped with active matrices. A special transistor is responsible for the value of the cells, which stores the value in binary code (0/1). This allows the pixel values ​​to be retained until the signal changes. This approach increased the screen refresh rate and eliminated flickering. The new active matrices are called TFT.

Types of TFT matrices

Types of TFT matrices

If you look at it, it turns out that the type of TFT matrix is ​​found in absolutely all liquid crystal monitors. As explained earlier, the technology is based on thin film transistors. This technology is considered the most advanced, and no affordable alternative has been found. The scheme of operation of such a mechanism is as follows.

In modern monitors, color is built according to the RGB scheme. This means that every single pixel can display red, green, or blue. And already from these basic colors all the rest are made up. It turns out that there are color cells in each pixel. There are three of them, and each has its own transistor connected, which tells which colors should be displayed at the moment. Such a scheme is understandable, but difficult to manufacture, especially considering how delicate these schemes are. Therefore, high-quality matrices cost a lot of money.

When the variety of technologies was not so great, monitors were called TFT. However, the type of TFT screen does not reveal all the technical characteristics embedded in it. Therefore, over time, such a signature was abandoned. Now there are three main subtypes of the matrix, each of which has its own distinctive features. They will be discussed in the following subsections.

The first in the list will be considered a TFT matrix called TN. It has retained the basic features of the first thin-film designs. Most often, such matrices are inexpensive to create, and therefore are on many budget monitors. Their native element is offices, home PCs, etc., as well as game models. Why this is so will become clear when we understand the main distinguishing features of TN.

The main advantage of TN technology is the low response time of the monitor. This is an indicator that characterizes the ability of a pixel to quickly change its glow. At TN, this figure is at a height due to the design features. Low response is very good for gamers. This allows them to instantly react to the slightest changes in the gameplay, as well as to increase the smoothness of the picture (this will reduce fatigue).

However, TN also has a "proprietary" minus - viewing angles. This flaw is most noticeable on laptops. The slightest change in the angle of view is enough for the colors to change their brightness beyond recognition. Of course, such a screen is not suitable for designers, artists and other professionals. However, the TN + Film type deserves the attention of professional gamers and moviegoers, since in it this parameter is brought to a more or less decent state.

The second type that we will consider is the IPS matrix. It can be considered the opposite of TN. Distinctive features are the saturation and accuracy of color reproduction, which do not change at all with a change in the angle of view. At the same time, this was achieved at the cost of reducing the response time. However, this parameter can be compensated for by the increased screen refresh rate. In addition, this parameter can be improved in some game models. However, the cost of IPS matrices is quite high, and this can also be considered one of the disadvantages.

The IPS matrix is ​​best suited for professionals working with color, images and 3D models. It is for such users that color rendition is most important. In combination with Super LCD backlight, such a tool can become a serious help in work. However, gamers will also be interested in devices in which the monitor's response has been accelerated.

Which is better Super LCD or TFT

When trying to choose a TFT display, you can resort to the comparison method. It is good when you need to choose one model from several similar ones, or understand which technology is suitable for a specific situation. Comparative tendencies, however, can be a trap. It's like comparing Windows to Linux. They have different areas of success, and what is good for one user will be superfluous for another. Therefore, before resorting to the comparison tool, you need to make sure that it will be appropriate. Otherwise, the comparison will be a waste of time.

An attempt to find out which is better - LCD or TFT just from this area. Those who carefully read the previous sections realized that LCD backlight and TFT display are not competitors, but two components that are inseparably symbiotic. One technology without the other would be useless, turning the monitor into a piece of plastic.

As for Super LCD, this is the unofficial name for a screen equipped with a high-quality LCD backlight and an IPS matrix. This name stuck due to the fact that the selected combination of technologies provides a bright image with correct color reproduction. If you choose between IPS (Super LCD) and TFT (its classic variation, TN), then the first option will be more technologically advanced.

Which type of matrix is ​​right for you

To choose a suitable TFT display, you first need to decide on the tasks that the PC user will have to solve. Using knowledge about the characteristic advantages of a particular technology, you can choose the type of TFT matrix that will be optimal in terms of price-quality ratio and technical characteristics.

For gamers, the following types are preferable: budget - TN TFT display, or IPS gaming modifications. Photographers, designers and architects need a flagship IPS. And for moviegoers and home PC owners, IPS or PLS are not required, although they remain the leaders in terms of color. In this case, you can choose VA or MVA matrices.

So, the TFT display is the basis for all monitors produced. The versatility of the technology allows it to be used in devices of various classes. Until science has made a new breakthrough, the TFT display will remain the uncontested production option.


What is TFT LCD Screen

What is TFT LCD Screen


TFT LCD (Thin Film Transistor Liquid Crystal Display) is the abbreviation of Thin Film Transistor Liquid Crystal Display. The cross section of the TFT panel is shown in Figure 1.

The structure of LCD is introduced. Polarizer.

The top polarizer can polarize stray light from random polarization in a given polarization direction. Before applying an electric field to the electrodes, the liquid crystals are arranged in a twisted structure. The light in this case changes according to the twisted structure of the liquid crystal. The lower polarizer is oriented perpendicular to the upper polarizer. When the light reaches the bottom polarizer, the two polarizers are aligned with each other. Light can pass through them unhindered, as shown in Figure 2

LCD structure introduction

Glass substrate, TFT substrate, color film substrate

Using high-precision photolithography, the pattern is applied to the glass substrate to gradually transfer the images of multiple LCD electrodes in sequence (Figure 3). TFT glass has as many transistors as there are pixels on the display, and color generation is provided by color filter glass with color filters. The movement of the liquid crystal is caused by the potential difference between the electrodes on the TFT glass and the color filter glass. It is this movement of the liquid crystal that produces the color and determines the brightness of the LCD.

LCD liquid crystal

Liquid crystals are almost transparent substances and exhibit the characteristics of crystals and liquids at the same time. Two glass plates sealed with epoxy resin and with a groove in the left corner allow the introduction of liquid crystals (under vacuum) before the final sealing of the glass plates. The potential difference determines the orientation of the liquid crystal. When polarizers and color filters are used, the difference in the orientation of the liquid crystal causes the difference in transmittance (or reflectance) and the resulting color. Liquid crystals are substances that present different phases (solid, liquid crystal or liquid) at different temperatures

Leveling film

The film is deposited on two glass plates (upper and lower), with a series of parallel grooves, so that the liquid crystal molecules are aligned in the appropriate direction (Figure 5 has a series of parallel grooves, so that the liquid crystal molecules are aligned in the corresponding direction)

LCD development

Liquid crystal was discovered more than 100 years ago. When heated, their external state can change from solid to liquid crystal, and even completely transform into liquid form as the temperature rises further. Over the years, people have made great efforts to improve liquid crystals, and as a result they have been widely used in electronic calculators and digital clocks. At present, the application range of color liquid crystal is wider: mobile phones, personal computers and TVs, which have the characteristics of low thickness, low power consumption, high resolution and brightness. In addition, in the foreseeable future, driven by the rapid spread of flat panel displays, the demand for LCD panels is expected to grow substantially.

How does LCD work

When a voltage is applied to the two LCD electrodes, the stronger the "unfolding" of the liquid crystal molecules, the higher the applied potential (Figure 6). Voltage sensitivity is one of the main characteristics of liquid crystals. Figure 7 shows the normal "white" mode of the LCD. As long as no potential difference is applied, light can pass through the liquid crystal layer, and the liquid crystal molecules will change the orientation of the light plane according to their own angle. However, when a voltage is applied, the liquid crystal molecules will "unfold" and "straighten" the light directed to the upper polarizing filter. Therefore, light will not be able to pass through the active area of the LCD, and this area will be darker than the surrounding area.

LCD control mode

Figure 8 shows the LCD control circuit. In a selected period of time, the switch is closed and an input voltage is applied to the liquid crystal, which will cause the orientation of the liquid crystal molecules to change. When the switch is closed, a certain charge is stored in Clc, and the voltage across Clc decreases with time. Consider adding a storage capacitor Cst in parallel with Clc to expand the storage capacity of the charge.

Energy storage capacitor

In fact, the control of the liquid crystal must be carried out by AC voltage. To activate the LCD, voltage is applied only when the switch is turned on, and then the switch is turned off immediately. In some cases, the voltage across the liquid crystal drops due to leakage. To prevent this, we can use a parallel capacitor to compensate for the leakage voltage. As the capacitance Cst increases, the shape of the voltage across it is close to a zigzag

The working principle of TFT LCD

The TFT acts as a switch. The gate of the TFT is connected to the scan line, the source is connected to the data line, and the drain is connected to Clc and Cst. When the shutter is activated (selected on the scan line), the TFT channel is opened, and the image data will be written into Clc and Cst. When the shutter is not selected, the TFT channel is closed

The basic structure of TFT LCD

The core of TFT-LCD structure includes liquid crystal, two polarizers and glass plate: upper color film substrate and lower TFT array substrate. Inject liquid crystal material between the two glass plates

Luminous flux adjustment

By controlling the magnitude of the input voltage applied to the liquid crystal, the arrangement, orientation and direction of the molecules can be changed, which will cause the volume of the luminous flux through the liquid crystal to change accordingly

Color formation

When the light flux passes through the color filter integrated in the top colored glass, each pixel of the image is formed by mixing basic RGB color elements (R-red, G-green, and B-cyan). If the red, green, and blue pixel elements are selected in equal proportions, white light will be produced. By adjusting the ratio of these three elements, the required number of different colors is obtained



The difference between AMOLED, OLED, IPS, TFT,LCD

AMOLED, OLED, IPS, TFT, etc.: What are the differences between these types of displays and which one is better

If a person "is famous for his clothes and his heart is his heart", then TVs, computer monitors, smartphones and tablets will appear on the display. They also often see off. When buying such a device, it is not always possible to personally evaluate the aesthetics and other characteristics of its screen, because many transactions are conducted over the Internet. However, if you know the meaning of the 3 letters, it is easy to understand the display effect of the device even if you do not see it.


For example, LED, LCD, IPS, TFT, OLED, QLED, AMOLED. All of these are screen manufacturing technologies that determine its characteristics. Let's talk about LED, AMOLED, QLED, OLED displays and their differences with IPS, TFT, LCD, etc.


LCD and LED LCD, TFT, LED, AMOLED and other "ice" are just abbreviations, the difference between them is worlds apart. In addition, some of these concepts are unparalleled. So, no one will tell you which TV is best: LCD or LED, because LCD (large iquid ç rystal d isplay) is a liquid crystal display or just LCD, and LED (large mitting d IODE) is one of the types Its backlight (LED). In other words, the TV can be LCD and LED at the same time

The structure diagram of the LED backlight LCD screen is shown in the figure below:

TFT and LCD "How about TFT TV? Is it better or worse than liquid crystal?" Not because TFT is a type of liquid crystal display in active matrix LCD. Active matrix is a display color management system in which each pixel is controlled by its own set of thin film micro transistors

The LCD screens of all modern TVs, monitors, smartphones, and tablets have an active matrix, so it is not appropriate to compare these devices with LCDs and TFTs. TFT and IPS. IPS properties and version "But IPS screens are definitely better than TFTs. It's not useless to write this on the forum!?" Again, those who write in this way did not guess. IPS is a type of TFT. Same as TN, PLS, VA, MVA, PVA, etc. TFT screens are sometimes erroneously called TN displays, which really do not serve the picture quality-of all TFT choices, they have the worst color rendering, the lowest brightness and contrast, and a very limited viewing angle. On the other hand, TN screens are known for their low cost, fast response and high refresh rate.

The next step is the development of active matrix technology, which eliminates the main shortcomings of TN. Change the position of the crystal and the voltage point on the battery to make the black become true black. When looking at the screen from the side, the color is the same as when looking at the front. In addition, the IPS screen has significantly improved color reproduction and increased overall brightness and contrast, but compared with TN, the response speed has decreased. Today, IPS is being developed in parallel by three companies-Panasonic (which took over the "baton" from Hitachi, the developer of the first version), NEC and LG. Each version and generation of the technology has its own characteristics and names. The product lineup of Hitachi and Panasonic includes: IPS (Super TFT), S-IPS (Super-IPS), AS-IPS (Advanced super-IPS), IPS-Pro (IPS-provectus, IPS alpha, IPS alpha next gen). The development of NEC is named: SFT (Super Fine TFT), A-SFT (Advanced SFT), SA-SFT (Super-advanced SFT), UA-SFT (Ultra-advanced SFT). The names of LG products are: S-IPS (Super-IPS), AS-IPS (Advanced super-IPS), H-IPS (Horizontal IPS), E-IPS (Enhanced IPS), P-IPS (Professional IPS) ), AH-IPS (Advanced High Performance IPS).

All developers are improving technology in the same direction. This is the reduction of response time, the increase of contrast, color depth and naturalness, the improvement of viewing angle, the elimination of color distortion, the reduction of power consumption, and most importantly-the reduction of matrix production costs. In recent years, IPS screen computer monitors have "followed TN" in response speed, and can be used not only for professional graphics cards, but also for dynamic games. Most users, except perhaps professionals in the field of graphics and design, will not notice the difference in pictures on IPS monitors of different brands, but there are also considerable differences between their budget and the high-end version. LG's P-IPS and AH-IPS matrix reproduce the highest image quality. They are the most expensive. VA / MVA / PVA Matrix VA, MVA and PVA occupy the middle position between TN and IPS in terms of image quality and price. Compared with TN, they have a wider viewing angle, more accurately convey the depth and naturalness of colors, and they are cheaper than IPS. However, these types of screens are not widely used. They are used to produce monitors for personal computers and budget TV series. There are several types of LED LCD backlight technology. They differ in color, the position of the LEDs on the LCD panel, and the way they dim. A backlight with only white LEDs is called WLED. Its structure is relatively simple, but its color gamut is limited. RGB LED backlights based on red, green and blue LEDs cover a wider range of colors than WLEDs, but are prone to degradation (different color diodes decay at different rates), are heavy and expensive. GB-R LED is the next step in the development of LCD, in which green + blue combination LEDs covered with red phosphors (self-luminous pigments) are used instead of white LEDs. This solution allows us to cover 99% of the RGB palette and get rid of the shortcomings of RGB LEDs. GB-R LED technology is used in AH-IPS and PLS matrix. The RB-G LED is a variation of the previous type of backlight. It is not a blue-green LED, but a red-blue LED covered with green phosphor.

According to the position of the light-emitting elements on the LCD panel, LED backlights are divided into the following types: Edge LED-LEDs are arranged linearly around the periphery of the screen. This is economical, but does not provide uniform illumination and acceptable contrast levels. Direct LED-LED array is distributed throughout the display area. This technology provides a more realistic picture, but this type of panels consumes a lot of energy and is thick, which makes them difficult to install on ultra-thin TVs. Side lighting-Diodes are located only at the edges of the screen, and light guides connected to them provide illumination. This type of backlight is considered the best because it provides uniformity comparable to that of direct LEDs without its disadvantages. The three types of backlights are divided into two types-support local dimming (Local Dimming) and dynamic contrast (DCR), or not. Local dimming and DCR screens look more realistic. OLED and AMOLED Although the concept of OLED is the same as that of LED, it actually has nothing in common with LED. OLED (ø rganic large flying e mitting d IODE)-an element capable of emitting light through electric current-this shows the manufacturing technology based on the performance of organic semiconductors. Each sub-pixel on an OLED screen is a separate organic light-emitting diode (OLED). Unlike LCDs, OLED panels do not require backlighting because they will light up with each point. Other characteristics and characteristics of OLED and LED: Due to the small number of layers, the thickness is small and the weight is light. Unlimited viewing angle. Even lighting. The fastest response time. flexibility. Significantly improve brightness, contrast and color saturation. Low sensitivity to external temperature, but high sensitivity to moisture. The service life is short and there is a tendency for degradation: the burn-out speed of blue diodes is 3 times faster than that of red, and almost 10 times faster than that of green. The dependence of resource consumption on screen brightness-the higher it is, the faster the fading will occur. Sensitivity to mechanical damage. A small defect can cause the screen to fail completely. Flicker is achieved by applying PWM (Pulse Width Modulation) to brightness control. The OLED screen uses PWM as an option. High price.