Stands for tft. Which is better PLS or IPS? How to Pick a Good Screen - Guide

The image is formed using individual elements, as a rule, through a scanning system. Simple devices (electronic clocks, telephones, players, thermometers, etc.) can have a monochrome or 2-5 color display. Multicolor images are rendered using 2008) in most TN (and some * VA) desktop monitors, as well as in all laptop displays, 18-bit color (6-bit per channel) matrices are used, 24-bit is emulated with dither flicker ...

LCD monitor structure

Color LCD subpixel

Each LCD pixel consists of a layer of molecules between two transparent electrodes, and two polarizing filters, the polarization planes of which are (usually) perpendicular. In the absence of liquid crystals, the light transmitted by the first filter is almost completely blocked by the second.

The surface of the electrodes in contact with liquid crystals is specially treated for the initial orientation of the molecules in one direction. In a TN matrix, these directions are mutually perpendicular; therefore, in the absence of stress, the molecules are arranged in a helical structure. This structure refracts light in such a way that before the second filter the plane of its polarization is rotated, and light passes through it without loss. Except for the absorption of half of the unpolarized light by the first filter, the cell can be considered transparent. If a voltage is applied to the electrodes, the molecules tend to line up in the direction of the field, which distorts the helical structure. In this case, the elastic forces counteract this, and when the voltage is turned off, the molecules return to their original position. With a sufficient field strength, almost all molecules become parallel, which leads to the opacity of the structure. By varying the voltage, you can control the degree of transparency. If a constant voltage is applied for a long time, the liquid crystal structure may degrade due to ion migration. To solve this problem, an alternating current is used, or a change in the polarity of the field with each addressing of the cell (the opacity of the structure does not depend on the polarity of the field). In the entire matrix, each of the cells can be controlled individually, but with an increase in their number, this becomes difficult, since the number of required electrodes increases. Therefore, row and column addressing is used almost everywhere. Light passing through the cells can be natural - reflected from the substrate (in LCD displays without backlighting). But more often they are used, in addition to independence from external lighting, it also stabilizes the properties of the resulting image. Thus, a full-fledged LCD monitor consists of electronics that process the input video signal, an LCD matrix, a backlight module, a power supply and a housing. It is the combination of these components that determines the properties of the monitor as a whole, although some characteristics are more important than others.

LCD Monitor Specifications

The most important characteristics of LCD monitors:

• Resolution: The horizontal and vertical dimensions, expressed in pixels. Unlike CRT monitors, LCDs have one, "native", physical resolution, the rest are achieved by interpolation.

Fragment of the LCD monitor matrix (0.78x0.78 mm), enlarged 46 times.

• Point size: the distance between the centers of adjacent pixels. Directly related to physical resolution.

• Screen aspect ratio (aspect): The ratio of width to height, for example: 5: 4, 4: 3, 5: 3, 8: 5, 16: 9, 16:10.

• Visible Diagonal: The size of the panel itself, measured diagonally. The area of ​​displays also depends on the format: a monitor with a 4: 3 aspect ratio has a larger area than a 16: 9 aspect ratio with the same diagonal.

• Contrast: The ratio of the brightness of the lightest and darkest points. Some monitors use an adaptive backlight level using additional lamps, the contrast figure shown for them (the so-called dynamic) does not apply to a static image.

• Brightness: The amount of light emitted from a display is usually measured in candelas per square meter.

• Response time: the minimum time it takes for a pixel to change its brightness. Measurement methods are ambiguous.

• Viewing angle: the angle at which the drop in contrast reaches a given value is calculated differently for different types of matrices and by different manufacturers, and often cannot be compared.

• Matrix type: the technology by which the LCD is made.

• Inputs: (e.g. DVI, HDMI, etc.)

Technologies

LCD clock

LCD monitors were developed in 1963 at RCA's David Sarnoff Research Center, Princeton, NJ.

The main technologies in the manufacture of LCD displays: TN + film, IPS and MVA. These technologies differ in the geometry of surfaces, polymer, control plate and front electrode. Great importance have the purity and type of liquid crystal polymer used in specific designs.

The response time of LCD monitors constructed using SXRD technology (eng. Silicon X-tal Reflective Display - silicon reflective liquid crystal matrix), reduced to 5 ms. Sony, Sharp and Philips have jointly developed PALC technology. Plasma Addressed Liquid Crystal - plasma control of liquid crystals), which combines the advantages of LCD (brightness and richness of colors, contrast) and plasma panels (large viewing angles horizontally, H, and vertical, V, high refresh rate). These displays use gas-discharge plasma cells as a dimmer and an LCD matrix for color filtering. PALC technology allows each display pixel to be addressed individually, which means unrivaled controllability and image quality.

TN + film (Twisted Nematic + film)

The “film” part in the name of the technology means an additional layer used to increase the viewing angle (approximately - from 90 ° to 150 °). Nowadays the prefix "film" is often omitted, calling such matrices simply TN. Unfortunately, no way has been found to improve contrast and response time for TN panels, and the response time for of this type matrices are currently one of the best, but the contrast level is not.

TN + film is the simplest technology.

The TN + film matrix works as follows: if no voltage is applied to the subpixels, liquid crystals (and the polarized light that they transmit) are rotated relative to each other by 90 ° in the horizontal plane in the space between the two plates. And since the polarization direction of the filter on the second plate makes an angle of 90 ° with the polarization direction of the filter on the first plate, light passes through it. When the red, green and blue subpixels are fully illuminated, a white dot appears on the screen.

The advantages of the technology include the smallest response time among modern matrices, as well as low cost.

IPS (In-Plane Switching)

In-Plane Switching technology was developed by Hitachi and NEC and was intended to overcome the shortcomings of TN + film. However, while IPS was able to achieve an increase in viewing angle of up to 170 °, as well as high contrast and color reproduction, the response time remained low.

At the moment, matrices made using IPS technology are the only LCD monitors that always transmit the full RGB color depth - 24 bits, 8 bits per channel. TN matrices are almost always 6-bit, as is the MVA part.

If no voltage is applied to the IPS matrix, the liquid crystal molecules do not rotate. The second filter is always rotated perpendicular to the first, and light does not pass through it. Therefore, the display of black is close to ideal. If the transistor fails, the “broken” pixel for the IPS panel will not be white, as for the TN matrix, but black.

When a voltage is applied, the liquid crystal molecules rotate perpendicular to their initial position and transmit light.

IPS is currently superseded by technology S-IPS(Super-IPS, Hitachi year), which inherits all the advantages of IPS technology while reducing the response time. But despite the fact that the color of S-IPS panels is close to that of conventional CRT monitors, contrast is still a weak point. S-IPS is actively used in panels starting from 20 ", LG.Philips, NEC remain the only panel manufacturers based on this technology.

AS-IPS- Advanced Super IPS technology was also developed by Hitachi Corporation in the year. The improvements were mainly related to the contrast level of conventional S-IPS panels, bringing it closer to that of S-PVA panels. AS-IPS is also used as the name for LG.Philips Corporation monitors.

A-TW-IPS- Advanced True White IPS, developed by LG.Philips for the corporation of the year. The increased power of the electric field made it possible to achieve even greater viewing angles and brightness, as well as to reduce the inter-pixel distance. AFFS-based displays are mainly used in tablet PCs based on matrices manufactured by Hitachi Displays.

* VA (Vertical Alignment)

MVA- Multi-domain Vertical Alignment. This technology was developed by Fujitsu as a compromise between TN and IPS technologies. Horizontal and vertical viewing angles for MVA matrices are 160 ° (on modern monitor models up to 176-178 degrees), while thanks to the use of acceleration technologies (RTC) these matrices are not far behind TN + Film in response time, but significantly exceed the characteristics of the latter the depth of colors and the accuracy of their reproduction.

MVA is the successor to VA technology introduced in 1996 by Fujitsu. When the voltage is off, the liquid crystals of the VA matrix are aligned perpendicularly to the second filter, that is, they do not transmit light. When voltage is applied, the crystals are rotated 90 °, and a light dot appears on the screen. As in IPS matrices, pixels do not transmit light in the absence of voltage, therefore, when they fail, they are visible as black dots.

The advantages of the MVA technology are deep black color and the absence of both a helical crystal structure and a double magnetic field.

Disadvantages of MVA in comparison with S-IPS: the disappearance of details in the shadows when viewed from a perpendicular view, the dependence of the color balance of the image on the angle of view, and a longer response time.

The following technologies are analogous to MVA:

• PVA (Patterned Vertical Alignment) from Samsung.
• Super PVA from Samsung.
• Super MVA from CMO.

MVA / PVA matrices are considered a compromise between TN and IPS, both in terms of cost and consumer qualities.

Advantages and disadvantages

Distortion on the LCD monitor at wide viewing angles

A closeup of a typical lcd matrix. In the center, you can see two defective subpixels (green and blue).

Currently, LCD monitors are the main, rapidly developing direction in monitor technology. Their advantages include: small size and weight in comparison with CRT. LCD monitors, unlike CRTs, have no visible flicker, focusing and beam convergence defects, magnetic field interference, and problems with image geometry and clarity. Power consumption of LCD monitors is 2-4 times less than that of CRT and plasma screens of comparable sizes. The power consumption of LCD monitors is 95% determined by the power of the backlight lamps or LED backlight matrix (eng. backlight- back light) LCD matrix. In many modern (2007) monitors, to adjust the brightness of the screen by the user, pulse-width modulation of backlight lamps with a frequency of 150 to 400 and more Hertz is used. LED backlighting is mainly used in small displays, although in recent years it has been increasingly used in laptops and even desktop monitors. Despite the technical difficulties of its implementation, it also has obvious advantages over fluorescent lamps, for example, a wider spectrum of radiation, and hence the color gamut.

On the other hand, LCD monitors also have some disadvantages, which are often difficult to eliminate in principle, for example:

• Unlike CRTs, they can display a clear image in only one ("native") resolution. The rest are achieved by lossy interpolation. And too low resolutions (for example 320x200) cannot be displayed on many monitors at all.
• Color gamut and color accuracy are lower than plasma panels and CRTs, respectively. Many monitors have fatal unevenness in brightness (gradient stripes).
• Many of the LCD monitors have relatively low contrast and black depth. Increasing the actual contrast is often associated with simply increasing the brightness of the backlight to an uncomfortable level. The widely used glossy coating of the matrix affects only the subjective contrast in ambient light conditions.
• Due to strict requirements for constant matrix thickness, there is a problem of uneven uniform color (uneven illumination).
• The actual picture change rate also remains lower than that of CRT and plasma displays. Overdrive technology only partially solves the speed problem.
• The dependence of the contrast on the viewing angle is still a significant disadvantage of the technology.
• Mass-produced LCD monitors are more vulnerable than CRTs. The matrix, which is not protected by glass, is especially sensitive. When pressed firmly, irreversible degradation is possible. There is also the problem of defective pixels.
• Contrary to popular belief, pixels on LCD monitors degrade, although the rate of degradation is the lowest of all display technologies.

OLEDs are often considered a promising technology that could replace LCD monitors. On the other hand, this technology met with difficulties in mass production, especially for matrices with a large diagonal.

see also

• Visible screen area
• Anti-reflective coating
• en: Backlight

Links

• Information on the fluorescent lamps used for the LCD backlight
• Liquid crystal displays (TN + film, IPS, MVA, PVA technologies)

Literature

• Artamonov O. Parameters of modern LCD monitors
• Mukhin I. A. How to choose an LCD monitor? ... "Computer-business-market", No. 4 (292), January 2005, pp. 284-291.
• Mukhin I.A. Development of liquid crystal monitors. "BROADCASTING Television and Radio Broadcasting": Part 1 - No. 2 (46) March 2005, p.55-56; Part 2 - No. 4 (48) June-July 2005, pp.71-73.
• Mukhin I. A. Modern flat-panel display devices. "BROADCASTING Television and Radio Broadcasting": No. 1 (37), January-February 2004, pp. 43-47.
• Mukhin I. A., Ukrainsky O. V. Methods of improving the quality of television images reproduced by liquid crystal panels. Materials of the report at the scientific and technical conference "Modern Television", Moscow, March 2006.

As is usually the case with abbreviations used to denote specificity and technical characteristics, confusion and substitution of concepts occurs in relation to TFT and IPS. Largely due to unqualified descriptions of electronic devices in catalogs, consumers put the question of choice initially incorrectly. So, the IPS matrix is ​​a kind of TFT matrix, so it is impossible to compare these two categories with each other. However, for the Russian consumer, the abbreviation TFT often means TN-TFT technology, and in this case it is already possible to make a choice. So, speaking about the differences between TFT and IPS screens, we will mean TFT screens made using TN and IPS technologies.
TN-TFT- the technology of performing a matrix of a liquid crystal (on thin-film transistors) screen, when the crystals, in the absence of voltage, rotate to each other at an angle of 90 degrees in the horizontal plane between two plates. The crystals are arranged in a spiral, and as a result, when the maximum voltage is applied, the crystals rotate so that when light passes through them, black pixels are formed. Without tension - white.
IPS- the technology of performing a matrix of a liquid crystal (on thin-film transistors) screen, when the crystals are located parallel to each other along a single plane of the screen, and not spirally. In the absence of voltage, the liquid crystal molecules do not rotate.
In practice, the most important difference between an IPS matrix and a TN-TFT matrix is ​​the increased contrast level due to the almost perfect display of black color. The picture is clearer.
The color reproduction quality of TN-TFT matrices leaves much to be desired. Each pixel in this case can have its own hue, different from the others, as a result of which the colors are distorted. IPS already handles the image much more carefully.
The response speed of the TN-TFT is slightly higher than that of other matrices. IPS takes time to rotate the entire array of parallel crystals. Thus, when performing tasks where drawing speed is important, it is much more profitable to use TN matrices. On the other hand, in everyday use, a person does not notice the difference in response time.
Monitors and displays based on IPS-matrices are much more power-hungry. This is due to the high level of voltage required to rotate the array of crystals. Therefore, the TN-TFT technology is more responsible for the tasks of saving energy in mobile and portable devices.
IPS-based screens have wide viewing angles, which means they don't distort or invert colors when looking at an angle. Unlike TN, IPS viewing angles are 178 degrees both vertically and horizontally.
Another difference, important for the end user, is the price. TN-TFT is by far the cheapest and most widespread version of the matrix, therefore it is used in budget electronics models.

TheDifference.ru determined that the difference between TFT (TN-TFT) and IPS screens is as follows:

IPS screens are less responsive and have longer response times.
IPS screens provide better color reproduction and contrast.
The viewing angles of IPS screens are significantly larger.
IPS screens require more power.
IPS screens are more expensive.

Good day.

When choosing a monitor, many users do not pay attention to the matrix manufacturing technology ( matrix - the main part of any lcd monitor, which forms the image), and on it, by the way, the quality of the picture on the screen depends very much (and the price of the device too!).

By the way, many may argue that this is a trifle, and any modern laptop (for example) provides an excellent picture. But these same users, if you put them on two laptops with different matrices - notice the difference in the picture with the naked eye (see fig. 1)!

Since a lot of abbreviated abbreviations have appeared recently (ADS, IPS, PLS, TN, TN + film, VA), it’s easy to get confused. In this article, I want to describe a little each technology, its pros and cons (it will turn out to be something in the form of a small reference article, which is very useful when choosing: a monitor, a laptop, etc.). So…

Rice. 1. The difference in the picture when the screen is rotated: TN-matrix VS IPS-matrix

Matrix TN, TN + film

Description of technical issues is omitted, some terms are "interpreted" in their own words so that the article is understandable and accessible to an unprepared user.

The most common type of matrix. When choosing inexpensive models of monitors, laptops, TVs - if you look at the advanced characteristics of the device you choose, you will surely see this matrix.

Pros:

1. very fast response time: thanks to this, you can observe a good picture in any dynamic games, films (and any scenes with a rapidly changing picture). By the way, for monitors with a long response time, the picture may start to "float" (for example, many complain about a "floating" picture in games with a response time of more than 9ms). For games, a response time of less than 6ms is generally desirable. In general, this parameter is very important and if you buy a monitor for games - the TN + film option is one of the best solutions;
2. Affordable Price: This type of monitor is one of the most affordable.

Minuses:

1. poor color rendering: Many people complain about not bright colors (especially after switching from monitors with a different type of matrix). By the way, some color distortion is also possible (therefore, if you need to choose the color very carefully, then you should not choose this type of matrix);
2. small viewing angle: Probably, many have noticed that if you approach the monitor from the side, then part of the picture is no longer visible, it is distorted and its color changes. Of course, TN + film technology somewhat improved this moment, but nevertheless the problem remained (although many may object to me: for example, on a laptop, this moment is useful - no one sitting next to you will be able to see exactly your image on the screen);
3. high probability of broken pixels: probably even many novice users have heard this statement. When a "broken" pixel appears, there will be a point on the monitor that will not display the picture - that is, there will be just a luminous point. If there are a lot of them, it will be impossible to work at the monitor ...

In general, monitors with this type of matrix are quite good (despite all their shortcomings). Suitable for most users who love dynamic movies and games. It is also very good to work with text on such monitors. For designers and those who need to see a very colorful and accurate picture, this type should not be recommended.

Matrix VA / MVA / PVA

(Analogs: Super PVA, Super MVA, ASV)

This technology (VA - vertical alignment in English) was developed and implemented by Fujitsu. Today this type of matrix is ​​not very common, but nevertheless, it is in demand among some users.

Pros:

1. one of the best black color reproduction: when looking at the monitor surface perpendicularly;
2. more quality colors(in general) compared to TN matrix;
3. enough good response time(quite comparable with TN matrix, though inferior to it);

Minuses:

1. higher price;
2. distortion of colors at a large viewing angle (this is especially noticed by professional photographers and designers);
3. possible "loss" of small details in the shadows (at a certain viewing angle).

Monitors with this matrix are a good solution (compromise) for those who are not satisfied with the color rendering of the TN monitor and who need a short response time. Those who need colors and picture quality - choose an IPS matrix (more on it later in the article ...).

IPS matrix

Varieties: S-IPS, H-IPS, UH-IPS, P-IPS, AH-IPS, IPS-ADS, etc.

This technology was developed by Hitachi. Monitors with this type of matrix are often the most expensive on the market. I think it makes no sense to consider each type of matrix, but it's worth highlighting the main advantages.

Pros:

1. better color rendering compared to other types of matrices. The picture is "juicy" and bright. Many users say that when working on such a monitor, their eyes practically never get tired (the statement is very controversial ...);
2. largest viewing angle: even if you stand at an angle of 160-170 degrees. - the picture on the monitor will be as bright, colorful and clear;
3. good contrast;
4. excellent black color.

Minuses:

1. high price;
2. long response time (may not suit some fans of games and dynamic films).

Monitors with this matrix are ideal for all those who need a high-quality and bright picture. If you take a monitor with a short response time (less than 6-5 ms), then it will be quite comfortable to play on it. The main drawback is the high price ...

PLS Matrix

This type of ball matrix was developed by Samsung (planned as an alternative to ISP matrix). Has both pros and cons ...

pros: Higher pixel density, high brightness, less power consumption.

Minuses: low color gamut, lower contrast compared to IPS.

By the way, the last tip. When choosing a monitor, pay attention not only to the specifications, but also to the manufacturer. I cannot name the best of them, but I recommend choosing a well-known brand: Samsung, Hitachi, LG, Proview, Sony, Dell, Philips, Acer.

On this note, I conclude the article, good choice everyone 🙂

And again the confusion of concepts. If you are trying to determine the difference between monitors or televisions, which someone called TFT and LCD, then you have been misled. Try to spot the differences between the bus and Ikarus? Between a dog and a neighbor's Bug? Between a fruit and an apple? That's right, the occupation is useless, because both objects are both at the same time. So it is with screen matrix technologies: LCD is the general name for a class of displays, which includes TFT.

Definition

TFT matrix- active matrix LCD-display, made on the basis of the use of thin-film transistors.

LCD- flat display (and a device based on it) based on liquid crystals.

Comparison

LCD displays are not an invention of our century. The screens of electronic clocks, calculators, devices, players are also liquid crystal, although they differ significantly from the screens of smartphones or TVs we are used to. True, at first LCDs were monochrome, but with the development of technology they flourished in the RGB gamut. TFT is also a kind of LCD-displays, the production of which is based on an active matrix on thin-film transistors. If you compare it with the earlier version of LCD, a passive matrix, it becomes obvious that the color quality and response time of TFT are much higher. A twisted polymer is used as crystals in passive matrices. But the power consumption and cost of passive matrices, called STN, can please anyone. However, monochrome screens in this regard will look like prize money at all, but there will hardly be many who want to watch such TVs.

The principle of TFT is that each of the thin film transistors drives a single pixel. There are three transistors for each pixel, corresponding to the RGB primary colors (red, green, and blue). The intensity of the light flux depends on polarization, polarization depends on the application of an electric field to liquid crystals. TFT assumes an increase in the level of performance, contrast and clarity of the resulting image.

It is worth noting the disadvantages of TFT matrices, eliminated in other technologies. The image quality is directly dependent on the ambient light of the screen. Transistors at any of the pixels can fail, which leads to the appearance of "dead spots", or dead pixels. Not a single screen can be insured against this. In addition, TFT matrices are largely energy-intensive, so their use as displays for mobile electronics makes one of the most important properties to be compromised - autonomy.

Thin-film transistors, which formed the basis of the operation of liquid crystal matrices, today have practically crossed over to another camp: OLED screens use them to control their active matrices. There are no longer liquid crystals, but organic compounds.

Conclusions site

1. LCD is a type of display matrix based on liquid crystals.
2. TFT is a type of active LCD-matrix.
3. TFT distinguishes itself from other LCD technologies by the use of thin film transistors.
4. TFT-matrices are economical, provide a high-quality picture, but power-consuming.

Technology does not stand still, and LCD production is no exception. However, due to the constant development and release of new technologies in the manufacture of screens, as well as due to special marketing approaches to advertising, many buyers when choosing a monitor or TV may have a question, which is better than an IPS or TFT screen?

To answer this question, you need to understand what IPS technology is and what a TFT screen is. Only by knowing this, you will be able to understand what is the difference between these technologies. This, in turn, will help you make the right choice of a screen that will fully meet your requirements.

1. So what is a TFT display

As you might have guessed, TFT is the abbreviated name for the technology. It completely looks like this - Thin Film Transistor, which in translation into Russian means a thin-film transistor. Basically, a TFT display is a type of liquid crystal display that is based on an active matrix. In other words, it is a conventional active matrix liquid crystal display. That is, the control of liquid crystal molecules occurs using special thin-film transistors.

2. What is IPS technology

IPS is also short for In-Plane Switching. It is a kind of active matrix LCD. This means that the question of which is better than TFT or IPS is erroneous, since they are essentially the same thing. More precisely, IPS is a type of FTF display matrix.

The IPS technology got its name due to the unique arrangement of the electrodes, which are on the same plane with the liquid crystal molecules. In turn, liquid crystals are located parallel to the plane of the screen. This solution made it possible to significantly increase the viewing angles, as well as increase the brightness and contrast of the image.

Today, there are three most common types of active matrix TFT displays:

• TN + Film;
• PVA / MVA.

Thus, it becomes obvious that the difference between TFT and IPS lies only in the fact that TFT is a type of LCD screen with an active matrix, and IPS is the same active matrix in a TFT display, or rather one of the types of matrices. It should be noted that such a matrix is ​​the most common among users all over the world.

3. What is the difference between TFT and IPS displays: Video

The common misconception that there is any difference between TFT and IPS has arisen from the marketing gimmicks of sales managers. In an effort to attract new customers, marketers do not disseminate full information about the technology, which creates the illusion that a completely new development is coming out into the world. Of course, IPS is a newer development than TN, but you cannot choose which TFT or IPS display is better for the above reasons.