Comparison of smartphone matrices. What is the difference between TN, IPS, AMOLED technologies. Types of screens in smartphones: which one to choose

Color LCD displays are divided into two types: active and passive. - this is “STN” (Super Twisted Nematic). Here, “nematic” denotes the type of liquid crystal used: nematic crystal molecules are characterized by the presence of orientational and lack of positional order. The technology of “twisted nematic” (twisted crystals) improves image contrast.

The basic principle of operation of STN: the image is formed line by line due to the sequential supply of control voltage to individual cells, which makes them transparent.

STN displays have worse characteristics than TFT displays: as a rule, they have a lower resolution and can display a significantly smaller number of colors. A serious disadvantage of STN matrices is the small viewing angle of the screen - it is better to look at it from a certain angle, then the colors will appear clear. In bright sunlight, such screens “blind” - the information on the display becomes difficult to see

However, STN displays are approximately three times cheaper than their TFT counterparts, so they are actively used by phone manufacturers in models in the budget price category, for example:,.

The graph compares the voltage transmittance across the electrodes of LCD displays based on a typical twisted nematic (TN) and a super twisted nematic (STN). (Actually, increasing the twist angle is equivalent to increasing multiplexing). The points on the graph V90 and V10 characterize the voltages at which light transmission is 90% and 10%, respectively.

The figure shows that the slope of the STN display characteristic is higher than that of the TN display, which allows the first type of display to be performed with a higher level of multiplexing. (Supernematics were developed primarily to overcome the difficulty of increasing the multiplexing level of TN displays.)

The multiplex ratio is equivalent to the number of rows that can be displayed simultaneously. For example, a display with a multiplex ratio of 400 to 400 lines of information can display simultaneously.

Passive matrix

This type of matrix is ​​called passive because it is not able to display information quickly enough: due to the large electrical capacitance of the cells, the voltage on them cannot change quickly enough, so the picture is updated slowly.

The passive matrix is ​​formed by superimposing layers of horizontal and vertical contact strips. Current is supplied to the vertical and horizontal strip, and the coordinates are specified. Where these stripes intersect, the crystals change structure, and a dot appears in the corresponding place on the screen.

Depending on the current, the crystals are distorted to a greater or lesser extent, allowing more or less light to pass through. In color displays, they also polarize light. When polarized from white light An electroluminescent backlight lamp “cuts out” certain color components in the required proportions, which ultimately determines the color of the screen dot. The technology is based on the principle of a passive matrix.

Modification of technology. CSTN (Color Super Twist Nematic) is a technology based on which displays for portable devices are made. In displays made using CSTN technology, each pixel has three separate pixels different color(Red, Green and Blue). Each pixel is controlled individually by the graphics controller chip. In fact, a CSTN display with a resolution of 320 x 240 pixels contains 960 x 240 individual color pixels.

The first CSTN displays had big time response and suffered from interference. Currently, displays based on CSTN matrices provide a response time of 100ms, a wide viewing angle (140 degrees) and high-quality colors that are almost as rich as TFT screens.

Technology modification - FSTN (Film Super Twisted Nematic). Matrix with film compensation, which improves the viewing angle. The technology differs from STN matrices only in that FSTN matrices have a special film on the outside that allows them to compensate for color shifts from blue to green to black to white.

In more detail, FSTN is a super-twisted nematic with film compensation. LCD with an additional film added to the outside of the cell to compensate for color shifts from blue to green to black to white. The film is made from a dual-refractive polymer to eliminate the possibility of color interference. As a result, compensation slows down.

Film ( upper layer in the figure) is located on the display below or above the upper polarizer. Some film compensation systems use two films, one on the rear side that serves as a collimator, and one on the front side that serves as a dispersion film, allowing a wider viewing angle. Film compensation improves viewing angle, but does not improve performance. FSTN - all standard STN displays with a polymer film applied to the glass as a compensating layer instead of the second cell like DSTN displays. This technology is characterized by a simpler and more cost-effective way of achieving a predominance of black over white in an image.

DSTN (Dual Super Twisted Nematic). Each cell of this matrix consists of two STN cells. Distinctive feature matrix is ​​that its entire field is divided into several independent matrix fields, each of which is controlled separately.

Active Matrix

Active matrices are abbreviated TFT (Thin Film Transistors) or AM (Active Matrix). In such matrices, under the surface of the screen there is a layer of thin-film transistors, semiconductors, each of which controls one point of the screen. Thus, in a color phone display their number can reach several tens, or even hundreds of thousands.

The basic principle of operation of the matrix is ​​to control the intensity of the light flux using its polarization. The polarization vector changes in liquid crystals depending on the electric field applied to them.

There are three transistors per pixel, each of which corresponds to one of the three primary colors - red, green or blue, and a capacitor that maintains the required voltage. This control method allows you to significantly speed up the operation of the display, although this is not a panacea - when playing a video, the image may be slightly “blurry”, since the crystals themselves will not have time to rotate with the required speed.

It happens that the transistor fails. Such a defect is easy to notice with the naked eye - a point on the screen constantly glows as a bright “star” against the background of others or does not glow at all. Therefore, when buying a mobile phone, do not be lazy to turn it on and take a close look at the display and, if you notice “broken” elements, change the device in time.

TFT (thin film transistor) is a type of liquid crystal display that uses an active matrix controlled by thin film transistors, that is, TFT - thin film transistor. Compared to a conventional passive liquid crystal matrix, using an active matrix controlled by thin-film transistors can significantly increase the performance of the display, as well as increase the contrast and clarity of the image.

TFT panel device : liquid crystal matrix with dividers (8); control plate (5,6 - horizontal and vertical control buses; 9 - thin-film transistors; 11 - rear electrodes); 10 - front electrode; 1 - glass plates; 2,3 - horizontal and vertical polarizers; 4 — RGB filter; 7 - layers of durable polymer; yellow arrow—light from an external source.

TFD (Thin Film Diode) is a technology for the production of liquid crystal displays using thin film diodes. It is similar to TFT technology, but here the transistors are replaced with thin-film control diodes. The main feature of such displays is reduced power consumption.

LTPS (Low Temperature Poly Silicon) is a technology for the production of LCD TFT displays using low-temperature polycrystalline silicon. This technology provides increased image indicator brightness and reduced power consumption.

UFB (Ultra Fine and Bright) is Samsung's own technology based on the use of a passive matrix. Such screens have increased brightness and contrast, while power consumption is reduced compared to traditional LCDs. UFB displays, capable of displaying 262 thousand colors, have a contrast ratio of 100:1 and a brightness of 150 cd/sq. m, while consuming no more than 3 mW. In addition, the production of the new display, according to the developers, is cheaper.

OLED (Organic Light Emitting Diodes) - electroluminescent displays based on organic light-emitting semiconductors. The main difference is that backlight lamps are not needed; in the new displays, surface elements glow directly. And they glow significantly brighter than LCD screens (100,000 cd/sq. m). At the same time, power consumption is lower, color rendition is better, contrast is higher (300:1), viewing angle is larger (up to 180 degrees), and color gamut is wider. Unlike a conventional LCD display, organics can respond 100–1000 times faster. The display thickness does not exceed 1 mm (including 2 mm protective glass), weight is calculated in grams. An important parameter is the operating temperature range: from -30 to +60 degrees. The only disadvantage we can note is the relatively low lifetime (about 5-8 thousand hours), however, this is quite enough for a phone. How do organic screens work? Once upon a time, the inventors of fluorescent diodes discovered that if they combine two layers of certain organic materials and pass an electric current through them at some point, a glow will appear at that place. At the same time, using different materials and filters, you can get different colors. Existing models, similar to LCDs, are divided according to the type of control matrix. There are OLEDs with passive and active matrices. The operating principle of the matrices is the same, but instead of a layer of liquid crystals, a layer of organic semiconductors is used.

If we compare modern OLED displays and good old LCD screens, the comparison will clearly not be in favor of the latter: LCD displays are already operating at the limit of their capabilities, the frame rate on the screen is low, and the power consumption, on the contrary, leaves much to be desired. Color LCD screens are difficult to see in sunlight and are quite fragile.

Of course, displays with active matrices (LCD TFT) are brighter and more contrasty than similar displays with passive matrices, but they are more difficult to manufacture, more expensive, and are used mainly in expensive devices.

The technology of organic displays is devoid of almost all the disadvantages characteristic of LCD displays, and provides much best characteristics Images. OLED Display - Physically, an organic electroluminescent display is an integral device consisting of several very thin organic films sandwiched between two conductors. Applying a small voltage (about 2-8 volts) to these conductors causes the display to emit light. The basis of the OLED matrix is polymer materials, their constant improvement greatly contributes to the improvement of displays and the development of matrix manufacturing technologies. Currently, two technologies are mainly being developed that have shown the greatest efficiency. They differ in the organic materials used: polymers (PLED) and micromolecules (sm-OLED). We will not consider them in detail, since for the phone user this is not of fundamental importance, and the manufacturer very rarely indicates the technical nuances of making the display in the phone specifications. What's good about OLED displays? Firstly, it is high brightness (up to 100 thousand cd/m2) and contrast (up to 300:1), which, in theory, should ensure readability of the display in any conditions. Next comes compactness and lightness, the display thickness does not exceed 1 mm (including 2 mm protective glass), weight is calculated in grams. The range of operating temperatures is also considered an important parameter. Both in severe winter (up to minus 30 degrees Celsius) and in summer on the beach (up to plus 60), the OLED display is operational. OLED displays are distinguished by decent mechanical strength and even... flexibility. However, the use of flexible substrates has already emerged as a separate area of ​​FOLED. And finally, unlike existing TFT and STN displays, OLED displays consume noticeably less energy. By analogy with other displays, it is also possible to use a passive or active matrix. Most often, OLED displays are used as external (or auxiliary) displays, since making the main display of a phone based on OLED technology is expensive, to say the least. For this same reason, these displays are usually limited to 256 colors. For example, such a display with a resolution of 94 x 94 pixels is used in the LG G7030, while the Samsung SGH-E700 has a slightly lower resolution (96 x 64 pixels). In general, such displays look very good, providing bright and readable picture, but, unfortunately, it is impossible to see anything on this display in the sun.

MEMS (Micro-Electro Mechanical Systems) - technology of microelectromechanical systems.

With the growing popularity of entertainment functions, including built-in high-resolution cameras, mobile phones have discovered a very serious drawback - the high power consumption of liquid crystal displays. In addition, with the massive spread of fashion for cameras, multimedia players and mobile games, the LCD screens of modern phones have become larger and brighter, and at the same time they remain on longer and longer, which ultimately leads to fast discharge batteries. Another disadvantage of TFT screens is the loss of readability of the information they display in bright sunlight, which often makes using the phone outdoors on a sunny day extremely inconvenient.

Thanks to MEMS, or more precisely, the iMoD (Interferometric Modulator - interference modulator) technology built on the basis of microelectromechanical systems by Iridigm engineers, mobile phone displays that “blind” in the sun and “fading” in order to save battery power may, after some time, become a thing of the past .

The operating principle of the iMoD display is that color image formed by the interference of light waves, similar to how daylight takes on a certain hue in the pollen-covered wings of a butterfly. Each iMoD pixel is a micromechanical system consisting of a transparent film and a mirror membrane, between which there is free air space. Interference occurs between light waves reflected from the film and waves passing through it and then reflected from the membrane. As a result, radiation appears a certain color, which can change from red to blue, depending on the size of the gap.

Structure of iMoD Interference Display

Displays built on the basis of this technology remain “readable” in any lighting. They have significantly lower power consumption compared to their liquid crystal competitors, since they do not require backlighting, and the energy in them is spent only on transferring the pixel from one state to another. It is also impossible not to note their small thickness - a godsend for mobile phone manufacturers, for whom the problem of saving space is extremely significant, especially in light of the increasingly popular ultra-thin models.

There are only two fundamental types of screen matrices used in modern smartphones - LCD and OLED. However, the number of subtypes, marketing terms and technologies that are used in their production and/or labeling can confuse even an electronics specialist. All these AMOLED, P-OLED, TN, OGS, In-Cell, TFT and other abstruse abbreviations do not make it clear to everyone what kind of beast is in front of them. One such confusing term is GFF.

GFF display is not a type of screen matrix, but an acronym that refers to the technology used in the manufacture of a single-piece display module. It stands for Glass to Film to Film, that is, literally, “glass to film to film.” As you can understand from the translation, this is a method of gluing a screen matrix with a sensor and protective glass using two films into a single piece.

GFF technology has similarities with . In particular, the screen module produced using it is a single part that cannot be divided into an LCD/OLED matrix and sensor without special equipment. However, the “anatomy” of GFF screens is different, and they themselves are easier to manufacture than OGS.

How does a GFF screen work in a smartphone?

Any touch screen contains three key components: a matrix that forms the image, a sensor that registers touches, and a protective coating that protects these two elements from damage. There are now two types of matrices in smartphones (see at the beginning), sensors are projection-capacitive, and tempered glass (Corning Gorilla Glass, Asahi DragonTail or others) is used to protect them.

The GFF display can be built on either an LCD (IPS, VA or TN) matrix or an OLED one. However, the first option is more common, since manufacturers of LED panels prefer to embed a touch grid directly on them. A layer of transparent LOCA glue or a special OCA adhesive film is applied on top of the GFF screen matrix, and another film with a transparent touch grid applied is glued to it. The next layer of this “sandwich” is OCA/LOCA, with which the glass of the display module is attached.

Scheme for gluing GFF screen parts

An exact list of devices with GFF is difficult, since there are so many of them. But it's safe to say that most of the available Xiaomi smartphones, Huawei, Meizu (and other large Chinese manufacturers), equipped with screens without an air gap, are equipped with GFF displays. OGS remains the domain of high-end devices equipped with LCD IPS matrices, such as the iPhone 8 or HTC U12+.

GFF variant with film-separated layers of X- and Y-axis sensor electrodes (red and blue)

Features of GFF screens and differences from OGS

The use of GFF modules allows you to equip your smartphone with a good matrix, while maintaining an affordable price. After all, gluing together an IPS panel, touch film and protective glass is much simpler and cheaper than integrating touch electrodes directly onto the matrix, on top of the pixels or between them, as in the case of OGS. Therefore, now most inexpensive smartphones whose screens are designated as OGS are actually equipped with modules produced using GFF technology.

Differences between OGS and GFF

In addition to the mentioned ease of production and low cost, GFF modules have good maintainability. Of course, at home, without special equipment, this is almost impossible (I tried it, but it didn’t work). But if only the glass and the sensor are damaged (with the entire matrix), only these parts can be replaced in the workshop, while if the touchscreen on the OGS is damaged, the entire module will be replaced.

The downside of screens produced using GFF technology is a little less transparency due to the presence of one or two more films. This means that when using two identical matrices, but one with OGS and the other with GFF, the brightness of the second will be slightly lower, with the same backlight energy consumption.

Today, smartphones are so similar to each other in appearance and technical characteristics that manufacturers have to compete in other areas. Some offer top-end cameras, others offer body protection, and others offer better screens that will blow your mind. Let's talk about popular technologies for manufacturing mobile displays: LCD, IGZO LCD, MLCD+, OLED and SuperAMOLED.

The average user of a mobile device does not look at the display except when using the smartphone for conversations. The rest of the time his eyes are glued to the picture on the screen. In 2018, it’s not enough just to have high resolution (although some manufacturers have succeeded here too) – it’s necessary to make color reproduction as realistic as possible. What technologies are used for this?

LCD

Liquid Crystal Display, also known as LCD, or liquid crystal display (LCD), is familiar to us not only from smartphones, but also from other electronics - TVs and laptops. The technology is based on liquid cyanophenyl crystals, which change their position under the influence of electric current. Following this, the polarization also changes, that is, these particles act as filters that transmit a certain color spectrum.

LCD displays are used in inexpensive smartphones, but not all manufacturers use this technology. For example, Qualcomm reported that they cannot combine scanners with LCD displays, since this requires expensive OLED matrices.

Advantages: good focusing and image clarity, minimum errors in beam convergence, minimum geometry violations, low weight.

Flaws: low brightness and contrast parameters, small margin of mechanical strength.

IGZO LCD

The most interesting thing about this technology is how its abbreviation stands for. Indium gallium zinc oxide translated means “Oxide of indium, gallium and zinc.” These substances became the basis for semiconductor material, which is used as a channel for thin-film transistors. The debut of IGZO technology took place in 2012 with the help of Sharp, which demonstrated the first panels based on IGZO LCD at an exhibition in Berlin. They do not require constant updating when demonstrating stationary objects, so they save battery energy, and this is important for modern smartphones!

The IGZO LCD matrix is ​​thinner and more transparent than IPS and LCD counterparts, does not require additional backlighting and produces high-definition images. These are consequences of the fact that the transistors themselves have become smaller, and the electrons in them move faster.

If the first smartphones with IGZO LCD displays were produced only by Sharp, then later other manufacturers became interested in them. For example, this was done by the manufacturer Meizu, which, with a short break, released two smartphones with similar matrices: M2 Note and M6 Note.

Advantages: top resolution, energy efficiency, fast sensor response, maximum angles review, high values brightness and contrast.

Flaws: price.

IPS

The first commercial IPS (in-plane switching) matrices ) appeared in 1996 thanks to the joint efforts of Hitachi and NEC. By the way, the second one uses the abbreviation SFT – Super Fine TFT – to denote this technology. Unlike LCD technology, IPS uses a different principle of arrangement of liquid crystal molecules. The latter are in the same plane and rotate synchronously under the influence of electric current.

The first IPS displays had long response times and high power consumption, but the technology has developed rapidly, and modern products no longer have these shortcomings.

Advantages: clarity and naturalness of color rendering, wide viewing angles (up to 178 degrees), high brightness and contrast values, good detail of small objects, energy efficiency, affordable cost.

Flaws: Slow response to touches on the screen.

Super AMOLED

This is the brainchild of the Korean company Samsung, which is sensitive to the image quality on its smartphones. It’s interesting that this manufacturer uses Super AMOLED (Active Matrix Organic Light-Emitting Diode) matrices not only on flagship devices, but also on budget models. The company first began using displays of this type in 2009, and the first commercial smartphones with them were Samsung Wave And Samsung Galaxy S – went on sale in 2010. The technology is based on organic light-emitting diodes, which are used as light-emitting elements. They are controlled by an active matrix of thin-film transistors.

The flagship Samsung Galaxy S9 and S9+, announced in 2018, received frameless SuperAMOLED displays with QHD+ resolution. Compared to the previous generation matrices, the brightness level has increased by 13%, which is now 1000 nits.

In Samsung smartphones, matrices of this type fit tightly to the screen itself, so there is no air gap between them. This primarily affects the compact design - it is thinner than display units made using other technologies.

Super AMOLED matrices are considered one of the most economical, since when the screen brightness is reduced, their power consumption is proportionally reduced. The color range they reproduce is 32% greater than that of LCD matrices. However, with intensive work at maximum brightness, the service life of the display quickly decreases - take this into account if you are buying a smartphone for 3-4 years.

Advantages: energy efficiency, thin screen thickness, maximum viewing angles, rich realistic colors, decent behavior in direct sunlight, high contrast and image brightness, response time - about 0.01 ms.

Flaws: fragility, rapid pixel burnout, predominance of violet and blue tints at low brightness values.

Along with Super AMOLED, Samsung uses Super AMOLED Plus matrices. They have less image grain and better color rendition. The company managed to achieve this thanks to Real-Stripe technology.

MLCD+

The second name of this technology is M+ LCD. Such displays differ from LCD solutions in the white pixel added by LG. She first did this in 2015 with her new line of TVs. Later, information appeared about the release of the LG G7 ThinQ smartphone with a screen made using a similar technology.

White color complements the three previously used subpixels: red, green and blue. By changing the transparency of the white subpixel, you can achieve more combinations of shades. This brings the quality of such an image as close as possible to that obtained using a Super AMOLED matrix.

In the summer of 2018, Apple announced that it plans to use MLCD+ displays in new iPhone smartphones.

Advantages: energy efficiency, high contrast, thin thickness.

Flaws: grainy, low reliability.

OLED

Organic light-emitting diode, also known as OLED (organic light-emitting diode) is a technology that is based on the use of organic polymers with a multilayer structure. They emit their own light when an electric current passes, while LED LCDs use external illumination for the subpixels. For the same reason, OLED panels are more compact than LCD.

OLED displays maintain natural color reproduction of images at any viewing angle and, most importantly, do not require additional backlighting. Matrices of this type are considered less harmful to the eyes, since they use selective backlighting. The LEDs turn on only in the area where it is needed.

Advantages: fast response, high contrast, natural color rendering.

Flaws: high cost, short service life of some phosphors (predominantly blue).

OLED matrices are often used in smart watches and fitness bracelets. Most often these are monochrome panels with good contrast and economical use of energy. In many ways, this is what allows fashionable gadgets to work without recharging from several days to a couple of weeks.

What technologies are gaining popularity?

It's unlikely that you've heard of Micro-LED (aka ILED) technology, but it has every chance of becoming popular in a few years. Unlike OLED, Micro-LED is based on an inorganic light-emitting diode. It is expected that smartphone manufacturers will be interested in the technology due to its advantages: high brightness and contrast values, minimum time response, compact size, the ability to increase image density up to 1500 ppi and low power consumption. Micro-LED panels are currently difficult to produce, but the process is expected to become cheaper in the future.

Quantum Dots technology (aka QD-LED and QLED) borrows something from liquid crystal displays, but in its case we are dealing with even smaller crystals with a glowing effect. Matrices of this type are distinguished by natural color reproduction, which Sony has already used in practice when it released a QD-LED TV in 2013. Mass production continues to be hampered by labor intensity and high production costs.

How else do mobile gadget displays differ?

In screen modules recent years Not only technology is important, but also image clarity. While some manufacturers boldly install matrices with Full HD (1920 x 1080) and Full HD+ (2160 x 1080) resolutions on smartphones in the mid-price segment, others attract buyers with 2K and even 4K displays - with a resolution of 2560 x 1440 and 3840 x 2160, respectively. The PPI parameter – the number of dots per inch – speaks even more eloquently about image clarity. The more there are, the less grainy the picture will be. Although already in Full HD resolution on a 5.5-inch diagonal you will hardly be able to see individual pixels.

Many new products go on sale with 2.5D displays. This designation has nothing to do with “under-three-dimensionality”. This is the marketing name for the shaped edge around the perimeter of the screen that makes the edges smoother. In this design, the device looks more premium, but adds worries to the owner. Now it will be difficult for him to find high-quality glass, and the protective properties of ordinary film, which manufacturers recommend sticking on, are highly questionable.

Apple was the first to use 2.5D glass in smartphone screens.

An even more advanced option is 3D glass. It can be curved in the most unpredictable way - for example, in the center (in a horizontal or vertical plane) or along the edges. The most striking examples of smartphones with 3D screens are LG G Flex and Samsung Galaxy Edge.

In the near future, we expect to see smartphones with flexible folding OLED displays from Samsung, completely bezel-less displays, and ones that occupy the entire front surface of the device. Will they become popular soon? We'll see in 2-3 years.

Modern devices are equipped with screens of various configurations. Main on this moment There are displays based on them, but different technologies can be used for them, in particular we are talking about TFT and IPS, which differ in a number of parameters, although they are descendants of the same invention.

Nowadays there are a huge number of terms that denote certain technologies hidden under abbreviations. For example, many may have heard or read about IPS or TFT, but few understand what the actual difference is between them. This is due to the lack of information in electronics catalogs. That is why it is worth understanding these concepts, and also deciding whether TFT or IPS is better?

Terminology

To determine what will be better or worse in each individual case, you need to find out what functions and tasks each IPS is responsible for. In fact, it is a TFT, or more precisely, a variety of it, in the manufacture of which a certain technology was used - TN-TFT. These technologies should be considered in more detail.

Differences

TFT (TN) is one of the methods for producing matrices, that is, thin-film transistor screens, in which the elements are arranged in a spiral between a pair of plates. In the absence of voltage supply, they will be turned to each other at right angles in the horizontal plane. The maximum voltage causes the crystals to rotate so that light passing through them results in the formation of black pixels, and in the absence of voltage - white.

If we consider IPS or TFT, the difference between the first and the second is that the matrix is ​​made on the basis described earlier, however, the crystals in it are not arranged in a spiral, but parallel to a single plane of the screen and to each other. Unlike TFT, the crystals in this case do not rotate under no-voltage conditions.

How do we see this?

If you look at IPS or visually, the difference between them is the contrast, which is ensured by almost perfect reproduction of black. The image will appear clearer on the first screen. But the quality of color rendering when using a TN-TFT matrix cannot be called good. In this case, each pixel has its own shade, different from the others. Because of this, colors are greatly distorted. However, such a matrix also has an advantage: it is characterized by the highest response speed among all currently existing ones. An IPS screen requires a certain time during which all parallel crystals will make a complete turn. However, the human eye hardly detects the difference in response time.

Important Features

If we talk about what is better in operation: IPS or TFT, then it is worth noting that the former are more energy-intensive. This is due to the fact that turning the crystals requires a considerable amount of energy. That is why, if a manufacturer is faced with the task of making their device energy efficient, it usually uses a TN-TFT matrix.

If you choose a TFT or IPS screen, it is worth noting the wider viewing angles of the second, namely 178 degrees in both planes, this is very convenient for the user. Others have proven unable to provide the same. And another significant difference between these two technologies is the cost of products based on them. TFT matrices are currently the cheapest solution, which is used in most budget models, and IPS belongs to a higher level, but it is not top-end either.

IPS or TFT display to choose?

The first technology allows you to obtain the highest quality, clearest image, but requires more time to rotate the crystals used. This affects response time and other parameters, in particular the rate at which the battery discharges. The color rendering level of TN matrices is much lower, but their response time is minimal. The crystals here are arranged in a spiral.

In fact, one can easily note the incredible gap in the quality of screens based on these two technologies. This also applies to cost. TN technology remains on the market solely because of price, but it is not capable of providing a rich and bright picture.

IPS is a very successful continuation in the development of TFT displays. A high level of contrast and fairly large viewing angles are additional advantages of this technology. For example, on TN-based monitors, sometimes the black color itself changes its hue. However, the high energy consumption of IPS-based devices forces many manufacturers to resort to alternative technologies or reduce this figure. Most often, matrices of this type are found in wired monitors that do not operate on a battery, which allows the device not to be so energy dependent. However, developments in this area are constantly underway.

A few years ago, when choosing a smartphone, a rare user wondered what kind of matrix it had and what technologies were used in production. Basically, the size of the display was assessed, some wanted a large one, while others wanted a small one. Today, the matrix is ​​a powerful argument when choosing a device, so this text will talk about what smartphone screens exist and which one is better to choose.

Currently, the type of display is one of the first criteria for choosing a phone, so it makes sense to start the review with the types of smartphone screens and their differences. There are not many types, but a lot depends on what the matrix costs. Smartphone displays today are manufactured using two main technologies:

• liquid crystals (LCD), these include IPS and TN matrices;
• organic light-emitting diodes – AMOLED.

TFT matrix is ​​the basis for creating all other types of smartphone displays. TFT can be deciphered as thin-film transistor; this is a thin film of transistors that controls each individual subpixel. Its existence became the basis for the production of all of the above matrices, including AMOLED. This is especially true for TN and IPS matrices, which sometimes makes their comparison not the most correct. The difference between them is that amorphous silicon is used for TN matrices, while polycrystalline silicon is used for IPS. Its advantage is high pixel density and low power consumption.

TN

TN matrix today considered the most inexpensive and easiest to produce. It has low viewing angles, low color accuracy, and poor contrast. Most often, this type of matrix is ​​installed in smartphones in the low-cost segment. The advantage of this type is the price, as well as low response time, which is important for playing games. Despite this, the disadvantages of TN displays outweigh the pros, so Today the technology is considered obsolete.

IPS

IPS matrices can be safely called the most common type of smartphone display. They have a wide viewing angle (can reach 180 degrees), realistic color reproduction, and high pixel density. In addition, they are quite inexpensive, which allows them to be installed in devices from the mid-price segment to the most expensive devices. IPS matrices have a division within the group:

• AH-IPS – created by LG;
• PLS – produced by the Samsung brand;
• Retina - Apple.

There is no particular point in comparing these matrices, since their characteristics are generally the same.

On a note! If we talk about cheap and expensive IPS matrices, the former can be distinguished by low color rendering (the picture fades at angles), as well as by fading as the device is used.

It is worth understanding that IPS matrices have many subtypes, each of which focuses on different aspects of work - energy efficiency, brightness, contrast. The most important advantage of an IPS display is natural color reproduction at the level of the matrix itself. Displays created using this technology do not require separate software settings or processor intervention in its operation. Everything is initially transferred as needed. These IPS matrices are better than AMOLED.

AMOLED

A separate segment includes matrices based on organic light-emitting diodes. This technology is called OLED; among phones, it is produced by the Samsung brand, which gave its development the name AMOLED. The difference between these matrices is low energy consumption, black depth and rich colors. Many people believe that AMOLED matrices are sometimes too saturated, so when making a smartphone, how the matrix is ​​configured is of great importance.

It may happen that the device will be too contrasty, and it will be extremely inconvenient to use. It was said above that the IPS display does not need adjustment, the same cannot be said about the AMOLED screen. Often, expensive phones have the best display in the world, but due to incorrect settings, it does not allow you to fully enjoy the image. A simple example The new 2017 iPhone X may serve. Apple bought displays from Samsung, but was unable to properly configure them to get a good image. In 2018, in the XS and XS Max models, the situation changed, the matrix remained the same, but the correct settings made the picture much better. Otherwise, AMOLED matrices can be called the best smartphone screen in 2018, and it is not surprising that the most expensive devices use these matrices as a screen.

Important! It’s worth knowing about AMOLEDs that they have a limited lifespan - about 3 years of continuous operation. Considering that the smartphone display is not always on, this is quite enough.

QLED

Separately, it is worth mentioning the technology for producing the matrix - QLED. She is currently active used in the production of televisions, but developments are underway to introduce these displays into the smartphone industry. In this case, the technology is based on quantum dots, which glow on their own. The advantage of a QLED matrix over AMOLED is better contrast, color accuracy, brightness, and lower energy consumption. In addition, they do not need to be fine-tuned like Amoled.

Bottom line

At the end of the conversation about matrix types, we can highlight the following: the best matrices in given time AMOLED, followed by IPS displays, which may differ in production technology. Sometimes a high-quality IPS screen may be slightly inferior to an AMOLED display, and this will only be noticeable in specialized tests, but not during normal use of the device. TN matrices are outdated, and there is no point in dwelling on them, since for the same price you can buy a simple IPS display, which will be better in comparison.

Design features of the screen

When choosing the best display, you should pay attention to other features of its manufacture - the presence of an air gap, curved edges, lack of frames, the number of simultaneous touches, pressing force.

Some technologies created by developers find their application in production, while others fade into oblivion over time, as not promising. The so-called OGS technology belongs to the first type, and at one time it created a real sensation. For a long time The smartphone screen structure was a kind of sandwich, which consisted of several layers - protective glass, an air gap, and the matrix itself. The essence of OGS is that engineers have learned to remove a layer of air, and thus the matrix becomes directly part of the protective glass. That is, the picture is on the glass, and not under it.

The difference in this case is noticeable even to the naked eye - The viewing angle becomes higher, and the picture is more accurate and rich in colors. Today, types of screens without an air gap have secretly become the main ones and are used in almost every device, regardless of price.

Important! The technology has its drawback - previously, in case of glass damage, it was necessary to replace only the top layer, that is, the glass; today the entire matrix requires replacement.

A fairly new trend that Samsung introduced to smartphones is a curved display. The first phone with a curved screen was Samsung Galaxy Edge. The curved edges of the matrix not only make the device visually more interesting, but also allow functions useful for the user to be placed on these edges. Moreover, visually the picture becomes more voluminous.

Samsung is an adept of the technology, and its phones have similar matrices. However, a few years ago you could find in store windows smartphones from LG Flex series, which had a bend in the center of the device in such a way that the device fit perfectly in the hand.

On a note! Another useful property developments from LG - protection of the device in case of a fall. When the phone fell face down, it hit the upper edges, but not the entire surface of the matrix, which saved it from having to be replaced.

LG's curved phones were not widely used, so the company has abandoned them today.

Another interesting trend associated with curved screens is 2.5D displays. Here it is not the matrix that is curved, but the surface of the screen in such a way that all the edges smoothly flow into each other. From the point of view of displaying information, there is no difference, but in terms of ergonomics, phones have become more comfortable, and similar glasses are found in many devices in the mid-price segment from a variety of manufacturers.

Frameless display

Another fashionable trend, but far from new in terms of its occurrence, is the absence of frames on the display. Sharp began producing similar matrices in 2014, but the world saw the first such smartphone in 2016, and it became Mi Mix from the Chinese brand Xiaomi. In fact, calling the devices frameless is not entirely correct, since there are still frames here, they just have a minimal size. At the moment, there are several variations of this design - matrices extended upward, when there are no frames on the sides, devices with a bottom edge, as well as screens that have almost no frames at all, and all the elements of the front panel are placed on a small patch on top.

The latest type of smartphones appeared in 2017 with the phone from Apple - iPhone X. Models that are released after this device are mostly made with just such displays. By reducing the frames, manufacturers managed to fit a large diagonal into a relatively small body. In addition, it has become possible to increase the aspect ratio of the usable display area. If previously 16:9 screens were considered the standard, today you can increasingly see phone with 18:9, 19:9 matrix.

On a note! It is important to understand that this technology does not carry any real benefits or advantages, so there is no answer to the question of which screen is better for a smartphone; it all depends on the preferences of the owner.

Pressure force

Pressure sensing technology originally appeared Apple's iPhone 6s smartphone. Its essence is that the display understands the force of pressing the screen, and depending on this it performs one or another action. At first glance, it seems that this is not very useful or convenient, but those users who have learned to use the function note an increase in the level of comfort.

In fact 3D Touch has three options– quick press, medium and long. The sensitivity of the matrix can be adjusted in the settings. What happens when you press one or another:

• a quick tap opens an application (image, file);
• the middle one opens a preview;
• long brings up a context menu that offers different options for action.

For example, by quickly clicking on the mail icon, the user will immediately be taken to the application, and if he clicks on the icon, a menu will appear with different actions - write a letter, read inboxes, etc.

At present technology is actively used by Apple, although in official information the brand says that in 2019 it will not be available in new devices. In addition, some Chinese brands are making attempts to use the development in their devices, but have not achieved much success in this field.

Number of touches

A fairly important parameter that many do not pay attention to is the number of simultaneous touches. It determines which tasks can be performed on the device and which cannot. Modern screen can recognize 2,3,5,10 touches. Every user uses this every day, but doesn’t even think about it.

On a note! The first phone that began to understand 2 touches was created by Apple. For him, two touches made it possible to scale the image by swiping two fingers in different directions of the display. Today any phone can do this.

The second model for using the device, which requires several touches, is games. Most often the user Uses at least 2 fingers when playing to control the character and perform other actions - running, hitting, shooting, acceleration. It's rare that a modern phone doesn't understand gestures. The ability to work with them again requires support for multiple touches. Many musicians install music programs on their devices where necessary press different keys at the same time, and this also requires the device to support multiple touches. The vast majority of expensive smartphones have a maximum number of touches - 10. In cheaper models, the number can be 5. A smaller number is practically never found.

Screen Cover Types

In the first generations of smartphones, and for some years after that, it was used as a display coating. thin plastic plate. It had a lot of disadvantages - it scratched quickly, broke, and had unpleasant tactile sensations. Over time, manufacturers began to work in this direction.

In many high-quality smartphones of recent years, you can see glass from Corning, which is called Gorilla Glass, as matrix protection. This is a scratch-resistant coating that is difficult to scratch or break. It does not distort colors, unlike the plastic layer. There are several generations, and the highest quality at the moment is the fifth, which can be found in premium phones. Previous generations are common among less expensive models.

The display glass constantly interacts with your fingers. Due to this, fingerprints, greasy stains and other unpleasant marks appear on the screen. To protect against their appearance, it was created grease-repellent layer, which is commonly called oleophobic. It not only resists fingerprints, but allows them to be easily removed. Another important point: with the presence of such coverage Sliding your finger across the screen becomes more enjoyable and easier.

Advice! Checking for the presence of an oleophobic layer is very simple - just drop a drop of water on the screen. The better the drop is preserved, that is, it does not spread, the higher the quality of the layer.

Anti-glare coating

Any smartphone owner has encountered a situation where in the summer, under direct sunlight, it is impossible to see anything on the display. There are two ways to deal with this:

• set the backlight brightness to maximum, which drains the battery faster and does not always help;
• use an anti-reflective layer.

Relatively recently, before the appearance of a special layer on matrices in the store, sellers offered to buy matte film, which has anti-glare properties. Its essence is that it scatters the sun's rays and increases visibility on the screen. The downside of such films is that color rendition is reduced, and you have to choose between losing color or getting the opportunity to get rid of glare.

Today, display manufacturers have created a similar layer that is applied directly to the screen. Its advantage is that the device does not glare in the sun, allowing you to see the image. In addition, this layer does not deteriorate like film, meaning it does not need to be replaced. But the most important difference from film - the layer does not affect the quality of color display, the screen remains bright and beautiful. The function is useful, so when choosing a smartphone, you should check with the seller whether it is on the matrix, and it is best to find out this information in advance in reviews of the device, as this is often not indicated in the technical specifications.

Selecting diagonal and resolution

Screen diagonal and resolution are important, and these two parameters always stand side by side. It can be argued that to some extent the other depends on one.

Diagonal selection

The diagonal is measured in inches. One inch equals 2.54 cm, that is, a five-inch screen equals 12.7 cm. It is correct to measure the diagonal of the screen solely along the matrix from one corner to the opposite without capturing the frame. The frame does not affect the diagonal, which is why in the description you can see the parameter - physical size, and it is measured in centimeters. Accordingly, to find out the diagonal of the screen, it is enough to measure the distance in cm from one corner to the other, and then divide this number by 2.54.

It's difficult to answer the question what is the optimal screen size. Modern smartphones offer users options from 3.5 to 7 inches. It is impossible to choose the best one here; it all depends on the preferences of the owner, as well as the model of use.

1. A buyer who does physical labor and uses a smartphone exclusively for calls will be more suitable for a small device, since the likelihood of damage to it is minimal.
2. For work and constant use of the Internet, it is more convenient to take the middle option from 5 to 5.7 inches. It is convenient for one-handed operation and fits perfectly in your pocket.
3. For those who draw, play, watch movies, read or give presentations on the device, excellent option There will be a device from 5.7 inches or more. Such phones are inconvenient to carry in your pocket and operate with one hand, but the size of the display will allow you to see the smallest details in the image.

In other words, when choosing a device, you need to understand what tasks it will perform, and also try the device for ergonomics.

This is interesting! The fashion for diagonal sizes is changing: once upon a time, manufacturers sought to reduce the display, and everyone wanted to buy a small device, then so-called phablets came into fashion - a transitional option from a smartphone to a tablet. Today, users want to get a phone that is small in size, but with a large matrix. This is facilitated by the emergence of new aspect ratios, as well as frameless devices.

If choosing a diagonal is quite difficult, then with resolution everything is a little simpler. The concept of permission is ratio of number of pixels per unit area. The higher this ratio, the clearer and more accurate the picture. It is worth understanding that the same resolution will look different on smartphone screens of different sizes. After all, the sheer number of pixels on a larger diagonal makes their density smaller, which means the picture becomes grainy. When selecting and comparing devices, this point must be taken into account. You can generally take the following dependence as a rule: large diagonal – high resolution.

Important! Pixel density is abbreviated as PPI. In fact, you don’t have to think about how many inches the screen is and what number of pixels it has, but compare it by density. For example, one phone has a PPI of 443, and another 403, which means that the first model will have a less grainy image.

Today there are no specific rules for phone resolution depending on the diagonal, but the most popular ones can be identified:

• 840*480 pixels – up to 4.5 inches;
• 1280*720 (HD) – from 4.5 to 5 inches;
• 1920*1080 (FHD) – from 5 inches and above.

In addition, in expensive devices with large diagonals there are more a high resolution, For example, QHD – 1440*2560 pixels. This is one of the highest pixel-to-area ratios, and today for an expensive smartphone, having a lower resolution is considered a disadvantage. At the same time, you should not overpay for such a resolution on a small matrix; the difference on a 5.5-inch diagonal between FHD and QHD resolutions will not be visible.

Smartphones with two screens

To conclude the topic of displays, we should recall another interesting trend that is not widespread, but is periodically encountered in smartphones. It's about about devices with two screens.

Usually the second display is small in size and serves to display additional information, such as notifications or control of certain functions. This is a rather unique feature that not every user needs, so smartphones with 2 screens are not very common.

The second display can be created using one of the technologies listed above - IPS or AMOLED, or it can be completely different - for example, with electronic ink technology. Initially, it was created for electronic books, since the peculiarity of the production of such matrices allows them to be optimal for reading (they do not flicker, the eyes do not get tired), and in addition, they have such minimal energy consumption that they practically do not drain the battery. An example of a phone with such a display is Russian YotaPhone, here the entire rear panel is an E-ink (electronic ink) matrix. It displays notifications, displays a clock and other useful functions.

One of prominent representatives modern devices with an auxiliary display – Meizu Pro 7. The additional screen is created using AMOLED technology, its diagonal is 1.9 inches and the resolution is 240*536 pixels. Serves to display a notification, take selfies with the main camera, and also perform a limited set of functions.

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