What is tft ips ogs. Electronic magazine “Electrical Solutions. The best smartphones with AMOLED matrices

Smartphone display technologies do not stand still; they are constantly being improved. Today there are 3 main types of matrices: TN, IPS, AMOLED. There are often debates about the advantages and disadvantages of IPS and AMOLED matrices and their comparison. But TN screens have not been in fashion for a long time. This is an old development that is now practically not used in new phones. Well, if it is used, it is only in very cheap state employees.

Comparison of TN matrix and IPS

TN matrices were the first to appear in smartphones, so they are the most primitive. The main advantage of this technology is its low cost. The cost of a TN display is 50% lower compared to the cost of other technologies. Such matrices have a number of disadvantages: small viewing angles (no more than 60 degrees. If more, the picture begins to distort), poor color rendition, low contrast. The logic of manufacturers to abandon this technology is clear - there are a lot of shortcomings, and all of them are serious. However, there is one advantage: response time. In TN matrices the response time is only 1 ms, although in IPS screens the response time is usually 5-8 ms. But this is just one plus that cannot be weighed against all the minuses. After all, even 5-8 ms is enough to display dynamic scenes, and in 95% of cases the user will not notice the difference between response times of 1 and 5 ms. In the photo below the difference is clearly visible. Note the color distortion at angles on the TN matrix.

Unlike TN, IPS matrices show high contrast and have huge viewing angles (sometimes even maximum). This type is the most common, and they are sometimes referred to as SFT matrices. There are many modifications of these matrices, so when listing the pros and cons, you need to keep in mind a specific type. Therefore, below, to list the advantages, we will mean the most modern and expensive IPS matrix, and to list the disadvantages, the cheapest.

Pros:

1. Maximum viewing angles.
2. High energy efficiency (low energy consumption).
3. Accurate color reproduction and high brightness.
4. The ability to use high resolution, which will give a higher pixel density per inch (dpi).
5. Good behavior in the sun.

Minuses:

1. Higher price compared to TN.
2. Distortion of colors when the display is tilted too far (however, viewing angles are not always maximum on some types).
3. Oversaturation of color and insufficient saturation.

Today, most phones have IPS matrices. Gadgets with TN displays are used only in the corporate sector. If a company wants to save money, then it can order monitors or, for example, cheaper phones for its employees. They may have TN matrices, but no one buys such devices for themselves.

Amoled and SuperAmoled screens

Most often, Samsung smartphones use SuperAMOLED matrices. This company owns this technology, and many other developers are trying to buy or borrow it.

The main feature of AMOLED matrices is the depth of black color. If you put an AMOLED display and an IPS side by side, then the black color on the IPS will seem light compared to the AMOLED. The very first such matrices had implausible color reproduction and could not boast of color depth. Often there was so-called acidity or excessive brightness on the screen.

But developers at Samsung have corrected these shortcomings in SuperAMOLED screens. These have specific advantages:

1. Low power consumption;
2. Better picture compared to the same IPS matrices.

Flaws:

1. Higher cost;
2. The need to calibrate (set) the display;
3. Rarely can the lifespan of diodes vary.

For the most TOP flagships AMOLED and SuperAMOLED matrices are installed due to better picture quality. Second place is occupied by IPS screens, although it is often impossible to distinguish between an AMOLED and an IPS matrix in terms of picture quality. But in this case, it is important to compare subtypes, and not technologies as a whole. Therefore, you need to be on guard when choosing a phone: often advertising posters indicate the technology, and not a specific matrix subtype, and the technology does not play a key role in the final quality of the picture on the display. BUT! If TN+film technology is indicated, then in this case it is worth saying “no” to such a phone.

Innovation

Removing the OGS air gap

Every year engineers introduce image enhancement technologies. Some of them are forgotten and not used, and some make a splash. OGS technology is just that.

Typically, a phone screen consists of protective glass, the matrix itself, and an air gap between them. OGS allows you to get rid of the extra layer - the air gap - and make the matrix part of the protective glass. As a result, the image appears to be on the surface of the glass, rather than hidden underneath it. The effect of improving display quality is obvious. Over the past couple of years, OGS technology has been unofficially considered a standard for any more or less normal phones. Not only expensive flagships are equipped with OGS screens, but also budget phones and even some very cheap models.

Screen glass bending

The next interesting experiment, which later became an innovation, is 2.5D glass (that is, almost 3D). Thanks to the curves of the screen at the edges, the picture becomes more voluminous. If you remember, the first samsung smartphone Galaxy Edge made a splash - it was the first (or not?) to have a display with 2.5D glass, and it looked amazing. There was even an additional one on the side Touchpad for quick access to some programs.

HTC was trying to do something different. The company created the Sensation smartphone with a curved display. In this way it was protected from scratches, although it was not possible to achieve any greater benefit. Nowadays, such screens cannot be found due to the already durable and scratch-resistant protective glass Gorilla Glass.

HTC didn't stop there. The LG G Flex smartphone was created, which not only had a curved screen, but also the body itself. This was the “trick” of the device, which also did not gain popularity.

Stretchable or flexible screen from Samsung

As of mid-2017, this technology is not yet used in any phone available on the market. However, Samsung in videos and at its presentations demonstrates AMOLED screens that can stretch and then return to their original position.

Photo of the flexible display fromSamsung:

The company also presented a demo video where you can clearly see the screen curving by 12 mm (as the company itself states).

It is quite possible that Samsung will soon make a very unusual revolutionary screen that will amaze the whole world. This will be a revolution in terms of display design. It's hard to even imagine how far the company will go with this technology. However, perhaps other manufacturers (Apple, for example) are also developing flexible displays, but so far there have been no such demonstrations from them.

The best smartphones with AMOLED matrices

Considering that SuperAMOLED technology was developed by Samsung, it is mainly used in models from this manufacturer. And in general, Samsung is leading the way in developing improved screens for mobile phones and televisions. We already understood this.

Today, the best display of all existing smartphones is the SuperAMOLED screen in the Samsung S8. This is even confirmed in the DisplayMate report. For those who don’t know, Display Mate is a popular resource that analyzes screens inside and out. Many experts use their test results in their work.

To define the screen in S8, we even had to introduce a new term - Infinity Display. It received this name due to its unusual elongated shape. Unlike its previous screens, Infinity Display has been seriously improved.

Here is a short list of benefits:

1. Brightness up to 1000 nits. Even in bright sunshine, the content will be highly readable.
2. A separate chip for implementing Always On Display technology. The already economical battery now consumes even less battery power.
3. Picture enhancement function. In Infinity Display, content without an HDR component gains it.
4. Brightness and color settings are automatically adjusted based on users' preferences.
5. Now there is not one, but two lighting sensors, which more accurately allows you to automatically adjust the brightness.

Even compared to the Galaxy S7 Edge, which had a “reference” screen, the S8's display looks better (on it, whites are truly white, while on the S7 Edge they go warmer).

But besides the Galaxy S8, there are other smartphones with screens based on SuperAMOLED technology. These are, of course, mostly models Korean company Samsung. But there are also others:

1. Meizu Pro 6;
2. OnePlus 3T;
3. ASUS ZenFone 3 Zoom ZE553KL – 3rd place in the TOP of Asusu phones (located).
4. Alcatel IDOL 4S 6070K;
5. Motorola Moto Z Play and others.

But it is worth noting that although the hardware (that is, the display itself) plays a key role, software is also important, as well as minor software technologies that improve picture quality. Super AMOLED displays They are famous primarily for their ability to widely regulate temperature and color settings, and if there are no such settings, then the point of using these matrices is slightly lost.

The screen is the face of a smartphone; it occupies most of the front surface and is necessary to control the gadget and perceive all information. It would probably be redundant to list all the functions of the display, since each of us perfectly understands how important this element is in a smartphone. Manufacturers spend millions of dollars on improving displays, delighting users with increasing resolution, improved color reproduction, new technologies and ever-expanding viewing angles. If among more or less expensive smartphones it is not difficult to find a model with a decent display, then in the budget segment, as a rule, screens with the minimum parameters necessary for modern times are presented (IPS technology, HD resolution). We don’t argue - this will be enough for many, but our goal today is to find interesting expensive smartphones with a good screen, preferably Full HD.

Let's start by declaring variables, i.e. let's figure it out What display parameters should you pay attention to:

• screen diagonal, i.e. its size. A large display makes reading and watching videos more comfortable, but too large will turn your smartphone into a shovel. Screen diagonals of modern smartphones start from 4.7 inches, and even such ones are difficult to find. The most popular format is no longer even 5 inches, but 5.5 dm. There are smartphones with a diagonal of 6 dm and even 6.5 dm. Here everyone chooses for themselves, but before buying it doesn’t hurt to hold the device in your hand to understand how convenient it will be to use. In the budget sector, smartphones with a wide variety of diagonals are presented;
• screen resolution– the number of pixels that form the image. The more there are, the higher quality and integrity the picture will be, and the smaller the individual image points will be. Manufacturers indicate the number of horizontal and vertical pixels in the form 320*480. Resolution has become the standard for budget smartphones HD – 720*1280 , and it is quite enough if the screen diagonal is 4.7 inches or less. Screens with a resolution of 540*960 are still found in the budget sector, but with a diagonal of 4.7-5.5 inches, individual pixels are very clearly visible, so we don’t even consider such models. If the diagonal is 5 inches or more, it is better to look to the side FullHDscreens, their resolution 1920*1080 . They allow you to create an ideal high-quality picture;
  
• pixel density– this is an indicator depending on the diagonal and resolution. It determines how many image pixels there are per inch of screen. It has been proven that at density 300ppiand above, our eye cannot distinguish the individual components of the picture(pixels) and perceives the picture as a whole. Apple, for example, is precisely why it does not use a resolution higher in its smartphones than what can provide 300 ppi at a certain diagonal. Other manufacturers have taken a different path, offering a pixel density of 500 ppi or more, which is achieved by using high-resolution screens (2K or QHD - 1440 * 2560, 4K or UHD - 3840 * 2160). It’s up to you to decide what this is, a publicity stunt or concern for the user, but we advise you to pay attention first of all to the pixel density indicator, and not to the resolution: if it is 300 ppi or more, we can safely take it. True, with the rapid growth of screen diagonals, it is not easy to find an inexpensive smartphone with such an indicator. Simple rule: if the diagonal is less than 4.7 dm, the resolution may beHD, if more – desirableFull HD, and they are already available in budget devices;
  
• screen type. We will not go into the details of how each type of screen constructs an image and will go straight to the facts. TN-matrices– the cheapest, not very contrasting, have poor color rendering and small viewing angles, but they are cheap. Today they are practically not used. IPS-matrices– standard for many smartphones. This screen provides good color reproduction, viewing angles and contrast, but consumes more energy than AMOLED-matrix. The latter, due to their structural features, do not require additional illumination; they provide the deepest black color, excellent color rendition, and consume a minimum of energy. Previously, AMOLED was installed only in the most expensive smartphones, but today everything has changed somewhat.

It is better to take a smartphone with a screen made according to OGS technologies, which provides no air gap between the sensor and the display. This allows you to achieve better color reproduction, wider viewing angles and a compact screen. However, if the glass breaks, you will have to replace the entire screen unit. Today, most smartphone screens are manufactured using OGS technology.

Wouldn't be amiss in a smartphone protective glass and oleophobic coating. The latter makes it much easier to keep the screen clean. This year's fashion trend is frameless screens- approaches and budget smartphones. It’s unusual to use such devices, but with standard smartphone sizes you can get a screen with a larger diagonal.

Now let's get to the fun part and arrange the smartphones from the cheapest to the slightly less cheap. All of them will cost you up to $130-150.

The smartphone was released in 2015 and at that time was premium. Today it is still on sale and in demand, and if you get a discount, you can buy the device for $85-90. Got the gadget metal body, fingerprint scanner and medium filling, memory can be expanded. The shooting quality is satisfactory, but in the dark it leaves much to be desired. The pride of the model is the screen, large, with good resolution and wide viewing angles, handles 10 simultaneous touches. At the minimum brightness level, the display allows you to use it comfortably at night, but if you examine the device in detail, you can find fault with the color rendering and the lack of an oleophobic coating. Otherwise, the gadget is not bad for its price.

OUKITEL U20 Plus

When purchased in Russia, the device will cost $110-120, you can even find it for $100, but when ordering from China you can save a couple of tens of dollars. Minimum price for it – $88. The smartphone itself began selling this year, and it immediately surprised us with its flagship aspirations. The manufacturer packaged the device in a nice case with 2,5 D-screen, supplied fingerprint scanner and dual camera, which is still rare in the budget segment. The large screen with Full HD resolution turned out to be very, very successful: color rendition is close to the most natural, brightness is adjustable within a wide range, and even in direct sunlight, the information on the display remains readable, viewing angles are wide, the screen processes up to 5 simultaneous touches. It is possible to customize color rendering and other display parameters to suit your needs. In other respects, this is an ordinary smartphone, the capabilities of which, however, are sufficient for the average user.

Leagoo KIICAA Mix

The device came out just the other day and became one of the first budget frameless smartphones. Previously similar devices were already presented in the inexpensive segment, but the screens left much to be desired. The company offers an excellent frameless frame for $105-120, and this is a modern trend. The screen occupies almost the entire front panel - a small space remains only at the bottom, where it is located Fingerprint's scanner. The quality of the screen is excellent: the brightness is adjustable over a wide range, making it convenient to use the device both at night and in bright light. Let's add here excellent performance, decent memory, dual camera with good photo quality, and you can get probably the most interesting offer in this price category, but there were some nuances.

To expand the boundaries of the screen, designers had to abandon the light and proximity sensor, peephole front camera move to the bottom and speaker- at the top end. This solution causes a lot of inconvenience, at least at first. But the earpiece turns on along with the normal one during sound playback and it turns out something like stereo. Another unpleasant feature is that it is used to connect headphones. USB port Type-C. But the device is lightweight, cheap, has a large screen and small sizes, fits comfortably in your hands and flies in most applications.

Xiaomi Mi4

The screen of this smartphone received Gorilla Glass III protective glass and oleophobic coating, on which the finger glides more easily, and all dirt is erased more easily. With a 5-inch diagonal Full HD resolution allows you to create incredibly clear images. By the way, the very fact that the device uses a 5-inch screen is an obvious plus for those who are looking for a more or less compact smartphone. The display recognizes up to 10 touches, has decent viewing angles, an impressive reserve of brightness and anti-reflective coating. This is one of best screens in the segment, so you can forgive the device for the fact that it was released in 2014 and then, by the way, was a flagship. The model is still actively sold in stores. The smartphone is productive, the camera module from Sony allows you to take excellent pictures. There is function fast charging . The downside is the lack of a slot for memory cards.

Prestigio Grace

Even if this is not the most powerful smartphone our rating, but it can boast AMOLED-matrix, so the image quality is very high. The seemingly small battery capacity will be enough for average work of 1-1.5 days, since the screen here is economical.

Alcatel POP 4S 5095K

An interesting inexpensive device that will be of interest to those who are guided by the name of the manufacturer when choosing. The company is well-known, regularly releases new models, and this time it presented a good budget device with a decent screen and average hardware. Device feature – availability fingerprint scanner. Stock technical capabilities will be more than enough for most users.

Leagoo T5

The device surprises, first of all, with its memory reserves, and then with its display parameters. Considering the price, we get a very decent device. Among the advantages metal body, dual camera, fingerprint scanner. As a result, we get a very solid device at an indecently low price for it, however, it will have to be ordered from the Middle Kingdom.

LeEco Le S3 X522

The smartphone is made in metal case, equipped with an excellent screen with protective glass. It’s difficult for even the most pedantic user to find fault with the picture the device produces. Many experts say that only flagship devices can compete with this screen, so the device can be called the best inexpensive smartphone with a good screen.

In other respects, this is a very decent smartphone. It's fast, has very good cameras and sound, though The usual headphone jack was abandoned here, replacing it with USB Type-C. During various promotions, the device can be purchased for $120.

Meizu M5 Note

Cute all metal smartphone completes our rating. Outwardly, it resembles a device of a much higher price category. The screen has become the pride of the device; it is juicy, bright and has extremely wide viewing angles. Eat oleophobic coating. We praise the device for its high performance, good battery life and functional shell. The camera is average, as in many Meizu, but otherwise everything is very good. If you get a promotion, you can buy the device a little cheaper.

How to choose from the variety of modern smartphones what is right for you? Today the bad-android team has prepared material with useful tips on the topic of display selection.

How not to overpay for a device? How can you figure out what to expect from it based on the type of display?

Types of matrices

IN modern smartphones are used three basic types of matrices.

The first of them, called - is based on organic light-emitting diodes. The remaining two types are based on liquid crystals - IPS And TN+film.

It is impossible not to mention the frequently encountered abbreviation TFT.

TFT- these are thin-film transistors that control subpixels of displays (subpixels are responsible for the three primary colors, on the basis of which “full” “multicolor” pixels are formed, which we will talk about a little later).

Technology TFT applies in all three types of matrices listed above. That is why the often used comparison TFT And IPS is essentially absurd.

For many years, the main material for TFT matrices was amorphous silicon. On this moment launched an improved production of TFT matrices, in which the main material is polycrystalline silicon, significantly increasing energy efficiency. The size of the transistors has also been reduced, which allows achieving the highest performance. ppi(pixel density).

So, we’ve sorted out the matrix base, it’s time to talk directly about the data types of matrices.

TN+film matrix

These matrices were the first to appear in smartphones. At the moment they remain the most primitive and, accordingly, cheap.

Advantages:

Affordable price

Flaws:

Small viewing angles (maximum 60 degrees)

Inverts images even at small angles

Low contrast level

Poor color rendering

Most manufacturers have practically abandoned the use of this type matrices due to too large quantity shortcomings.

IPS matrix

At the moment, this type of matrix is ​​the most common. Also, IPS matrices are sometimes designated by the abbreviation S.F.T..

Story IPS-matrix originates several decades ago. During this period, many different modifications and improvements were developed IPS-displays.

When listing the advantages and disadvantages of IPS, it is necessary to take into account the specific subtype. To summarize, for the list strengths IPS let’s take the best subtype (and therefore the most expensive), and for the cons we’ll mean the cheapest subtype.

Advantages:

Excellent viewing angles (maximum 180 degrees)

High-quality color rendition

Possibility of producing high ppi displays

Good energy efficiency

Flaws:

Picture fades when the display is tilted

Possible oversaturation or, conversely, insufficient color saturation

AMOLED matrix

The matrix provides the deepest black color, compared to the other two types of matrices. But it was not always so. The first AMOLED matrices had implausible color reproduction and insufficient color depth. There was some acidity in the picture, too intense brightness.

Until now, due to internal incorrect settings, some displays are almost identical in perception to IPS. But in super-AMOLED displays, all flaws were successfully fixed.

When listing the advantages and disadvantages, let’s take a regular AMOLED matrix.

Advantages:

The highest quality picture among all existing types of matrices

Low power consumption

Flaws:

Rarely occurring uneven lifespan of LEDs (different colors)

The need for careful configuration of the AMOLED display

Let's sum up the intermediate results. Obviously, the matrices are leaders in image quality. It is AMOLED displays that are installed on the most top-end devices. In second place are IPS matrices, but you should be careful with them: manufacturers rarely indicate the subtype of the matrix, and this is what plays a key role in the final level of the image. An unambiguous and firm “no” should be said to devices with TN+film matrices.

Subpixels

The determining factor in the final quality of the display is often hidden display characteristics. Image perception is strongly influenced by subpixels.

In case of LCD the situation is quite simple: everyone is colored ( RGB) pixel consists of three subpixels. The shape of the subpixels depends on the modification of the technology - a subpixel can be shaped like a “check mark” or a rectangle.

In the implementation of displays in terms of subpixels, everything is somewhat more complicated. In this case, the light source is the subpixels themselves. As you know, the human eye is less sensitive to blue and red colors, in contrast to green. That is why repeating the IPS subpixel pattern would significantly affect the picture quality (of course, in the worst side). To preserve the realistic color rendering, technology was invented.

The essence of the technology is to use two pairs of pixels: RG (red-green) and BG (blue-green), which, in turn, consist of corresponding subpixels of the corresponding colors. A combination of subpixel shapes is used: green ones have an elongated shape, and red and blue ones are almost square.

The technology turned out to be not very successful: the white color was frankly “dirty”, and notches appeared at the junctions of different shades. At a low rate ppi a grid of subpixels became visible. Such matrices have been installed on a number of smartphones, including flagships. The last flagship that was “lucky” to get a PenTile matrix was Samsung Galaxy S III.

Naturally, it was impossible to leave the situation with low-quality implementation of subpixels in the same state, so soon the upgrade above the described technology, which received the prefix Diamond.

By increasing ppi Diamond PenTile made it possible to get rid of the problem with jagged boundaries between colors, and white became much “cleaner” and more pleasing to the eye. And it is this development that is installed in all Samsung flagships, starting with the Galaxy S4.

And here IPS-matrices, although they are generally considered weaker than ’ov’s ones, however, have never encountered such problems.

What conclusion can be drawn? Be sure to pay attention to the quantity ppi in case of purchasing a smartphone with an -matrix. A high-quality picture is only possible with an indicator of 300 ppi. But with IPS matrices do not have such strict restrictions.

Innovative technologies

Time does not stand still; talented engineers continue to work painstakingly to improve all characteristics of smartphones, including matrices. One of the latest serious developments is technology O.G.S..

O.G.S. is an air gap between the screen itself and the projective-capacitive sensor. In this case, the technology met expectations 100%: color rendering quality, maximum brightness and viewing angles increased.

And over the past few years O.G.S. It has become so embedded in smartphones that you won’t find the implementation of a “hamburger” display filled with an air gap except on the simplest devices.

In their search for display optimization, designers came across another interesting opportunity to improve the picture on phones. In 2011, experiments began on shape glass Perhaps the most common form of glass among the unusual ones has become 2.5D- with the help of curved edges of the glass, the edges become smoother and the screen becomes more voluminous.

Company HTC released a smartphone Sensation, the glass of which was concave in the center of the display. According to HTC engineers, this increases protection from scratches and impacts. But glass concave to the center never received widespread use.

The concept of bending the display itself, and not just the glass, as was done in . One of the side edges of the display has a curved shape.

Very interesting characteristic, which you should pay attention to when buying a smartphone is sensor sensitivity. Some smartphones are equipped with a sensor with increased sensitivity, which allows you to fully use the display even with regular gloves. Also, some devices are equipped with an inductive substrate to support styluses.

So for those who like to text in the cold or use a stylus, the sensitive sensor will definitely come in handy.

Known truths

It's no secret that screen resolution also greatly affects the final level of the image. Without further comment, we present to your attention a table of correspondence between display diagonal and resolution.

Conclusion

Each matrix has its own characteristics and hidden characteristics. You should be careful with -displays, or rather, with the ppi pixel density indicator: if the value less than 300 ppi, then the picture quality will tell you frankly will disappoint.

For IPS-matrix is ​​important subtype, and depending on the subtype, the cost of the smartphone logically increases proportionally.

Curved glass 2.5D will significantly increase the attractiveness of the picture, as will technology O.G.S..

The issue of display size is a purely individual one, but with multi-inch “shovels” a high resolution would be appropriate.

We wish you pleasant shopping, friends!

Stay tuned, more to come a lot of interesting.

Before the mass adoption of smartphones, when buying phones, we evaluated them mainly by design and only occasionally paid attention to functionality. Times have changed: now all smartphones have approximately the same capabilities, and when looking only at the front panel, one gadget can hardly be distinguished from another. Came to the fore specifications devices, and the most important among them for many is the screen. We will tell you what lies behind the terms TFT, TN, IPS, PLS, and help you choose a smartphone with the desired screen characteristics.

Types of matrices

Modern smartphones mainly use three matrix production technologies: two are based on liquid crystals - TN+film and IPS, and the third - AMOLED - based on organic light-emitting diodes. But before we begin, it’s worth talking about the acronym TFT, which is the source of many misconceptions. TFT (thin-film transistor) are thin-film transistors that are used to control the operation of each subpixel of modern screens. TFT technology is used in all of the above types of screens, including AMOLED, therefore, if somewhere they talk about comparing TFT and IPS, then this is a fundamentally incorrect formulation of the question.

Most TFTs use amorphous silicon, but recently polycrystalline silicon TFTs (LTPS-TFTs) have been introduced into production. The main advantages of the new technology are reduction in power consumption and transistor sizes, which allows achieving high pixel densities (more than 500 ppi). One of the first smartphones with an IPS display and LTPS-TFT matrix was OnePlus One.

OnePlus One smartphone

Now that we have dealt with TFT, let's move directly to the types of matrices. Despite the wide variety of LCD varieties, they all have the same basic operating principle: the current applied to the liquid crystal molecules sets the polarization angle of the light (it affects the brightness of the subpixel). The polarized light then passes through the filter and is colored to match the color of the corresponding subpixel. The first to appear in smartphones were the simplest and cheapest TN+film matrices, the name of which is often abbreviated to TN. They have small viewing angles (no more than 60 degrees when deviating from the vertical), and even with slight tilts the image on screens with such matrices is inverted. Other disadvantages of TN matrices include low contrast and low color accuracy. Today, such screens are used only in the cheapest smartphones, and the vast majority of new gadgets already have more advanced displays.

The most common technology in mobile gadgets now is IPS technology, sometimes referred to as SFT. IPS matrices appeared 20 years ago and since then have been produced in various modifications, the number of which is approaching two dozen. However, it is worth highlighting among them those that are the most technologically advanced and are actively used at the moment: AH-IPS from LG and PLS from Samsung, which are very similar in their properties, which was even the reason for litigation between manufacturers . Modern modifications of IPS have wide viewing angles that are close to 180 degrees, realistic color reproduction and provide the ability to create displays with high pixel density. Unfortunately, gadget manufacturers almost never report the exact type of IPS matrix, although when using a smartphone, the differences will be visible to the naked eye. Cheaper IPS matrices are characterized by fading of the image when the screen is tilted, as well as low color accuracy: the image can be either too “acidic” or, on the contrary, “faded”.

As for energy consumption, in liquid crystal displays it is mostly determined by the power of the backlight elements (in smartphones LEDs are used for these purposes), so the consumption of TN+film and IPS matrices can be considered approximately the same at the same brightness level.

Matrixes created on the basis of organic light-emitting diodes (OLED) are completely different from LCDs. In them, the light source is the subpixels themselves, which are subminiature organic light-emitting diodes. Since there is no need for external backlighting, such screens can be made thinner than LCD ones. Smartphones use a type of OLED technology - AMOLED, which uses an active TFT matrix to control subpixels. This is what allows AMOLED to display colors, whereas regular OLED panels can only be monochrome. AMOLED matrices provide the deepest blacks, since to “display” them you only need to turn off the LEDs completely. Compared to LCDs, such matrices have lower power consumption, especially when using dark themes, in which the black areas of the screen do not consume energy at all. Another characteristic feature of AMOLED is that colors are too saturated. At the dawn of their appearance, such matrices really had implausible color rendering, and although such “childhood sores” are long in the past, most smartphones with such screens still have a built-in saturation adjustment, which allows the image on AMOLED to be closer in perception to IPS screens.

Another limitation of AMOLED screens used to be the uneven lifespan of LEDs of different colors. After a couple of years of using the smartphone, this could lead to subpixel burnout and residual images of some interface elements, primarily in the notification panel. But, as in the case of color rendering, this problem is a thing of the past, and modern organic LEDs are designed for at least three years of continuous operation.

Let's summarize briefly. The highest quality and brightest images at the moment are provided by AMOLED matrices: even Apple, according to rumors, will use such displays in one of the next iPhones. But it’s worth considering that Samsung, as the main manufacturer of such panels, keeps all the latest developments for itself, and sells “last year’s” matrices to other manufacturers. Therefore, when choosing a non-Samsung smartphone, you should look towards high-quality IPS screens. But under no circumstances should you choose gadgets with TN+film displays - today this technology is already considered outdated.

The perception of the image on the screen can be influenced not only by the matrix technology, but also by the pattern of subpixels. However, with LCDs everything is quite simple: each RGB pixel in them consists of three elongated subpixels, which, depending on the modification of the technology, can be shaped like a rectangle or a “tick”.

Everything is more interesting in AMOLED screens. Since in such matrices the light sources are the subpixels themselves, and the human eye is more sensitive to pure green light than to pure red or blue, using the same pattern in AMOLED as in IPS would degrade color reproduction and make the picture unrealistic. An attempt to solve this problem was the first version of PenTile technology, which used two types of pixels: RG (red-green) and BG (blue-green), consisting of two subpixels of corresponding colors. Moreover, if the red and blue subpixels had a shape close to squares, then the green ones looked more like highly elongated rectangles. The disadvantages of this design were the “dirty” white color, jagged edges at the junction of different colors, and at low ppi - a clearly visible grid of subpixels, appearing due to too much distance between them. In addition, the resolution indicated in the characteristics of such devices was “dishonest”: if the IPS HD matrix has 2,764,800 subpixels, then the AMOLED HD matrix has only 1,843,200, which led to a difference in the clarity of IPS and AMOLED matrices visible to the naked eye. seemingly the same pixel density. Last flagship smartphone With such an AMOLED matrix, the Samsung Galaxy S III became available.

On a smartpad Galaxy Note II, the South Korean company made an attempt to abandon PenTile: the device’s screen had full-fledged RBG pixels, albeit with an unusual arrangement of subpixels. However, for unclear reasons, Samsung subsequently abandoned such a design - perhaps the manufacturer was faced with the problem of further increasing ppi.

In their modern Samsung screens returned to RG-BG pixels using a new pattern type called Diamond PenTile. New technology made the white color more natural, and as for jagged edges (for example, around a white object on a black background individual red subpixels were clearly visible), this problem was solved even more simply - by increasing the ppi to such an extent that the irregularities were no longer noticeable. Diamond PenTile is used in all Samsung flagships starting with the Galaxy S4 model.

At the end of this section, it is worth mentioning one more pattern of AMOLED matrices - PenTile RGBW, which is obtained by adding a fourth, white, subpixel to the three main subpixels. Before the advent of Diamond PenTile, such a pattern was the only recipe for pure white color, but it never became widespread - one of the last mobile gadgets with PenTile RGBW was Galaxy tablet Note 10.1 2014. Nowadays AMOLED matrices with RGBW pixels are used in TVs, since they do not require a high ppi. To be fair, we also mention that RGBW pixels can also be used in LCDs, but we are not aware of examples of the use of such matrices in smartphones.

Unlike AMOLED, high-quality IPS matrices have never experienced quality problems associated with subpixel patterns. However, Diamond PenTile technology, coupled with high pixel density, has allowed AMOLED to catch up and overtake IPS. Therefore, if you choose gadgets pickily, you should not buy a smartphone with an AMOLED screen that has a pixel density of less than 300 ppi. At a higher density, no defects will be noticeable.

Design features

The variety of displays on modern mobile gadgets does not end with imaging technologies alone. One of the first things that manufacturers took on was the air gap between the projected capacitive sensor and the display itself. This is how OGS technology was born, combining the sensor and matrix into one glass package in the form of a sandwich. This gave a significant leap in image quality: maximum brightness and viewing angles increased, color rendition was improved. Of course, the thickness of the entire package has also been reduced, allowing for thinner smartphones. Alas, the technology also has disadvantages: now, if you break the glass, it is almost impossible to change it separately from the display. But the quality advantages turned out to be more important, and now non-OGS screens can only be found in the cheapest devices.

Popular in Lately steel and experiments with glass shapes. And they started not recently, but at least in 2011: HTC Sensation had a concave glass in the center, which, according to the manufacturer, was supposed to protect the screen from scratches. But such glass reached a qualitatively new level with the advent of “2.5D screens” with glass curved at the edges, which creates the feeling of an “infinite” screen and makes the edges of smartphones smoother. He actively uses such glasses in his gadgets. Apple company, and lately they have become more and more popular.

A logical step in the same direction was the bending of not only the glass, but also the display itself, which became possible when using polymer substrates instead of glass. Here the palm, of course, belongs to Samsung with its Galaxy smartphone Note Edge, in which one of the side edges of the screen was curved.

Another method was proposed by LG, which managed to bend not only the display, but also the entire smartphone along its short side. However, the LG G Flex and its successor did not gain popularity, after which the manufacturer abandoned further production of such devices.

Also, some companies are trying to improve human interaction with the screen by working on its touch part. For example, some devices are equipped with highly sensitive sensors that allow you to operate them even with gloves, while other screens receive an inductive substrate to support styluses. The first technology is actively used Samsung companies and Microsoft (formerly Nokia), and the second - Samsung, Microsoft and Apple.

The future of screens

Don’t think that modern displays in smartphones have reached the highest point of their development: technology still has room to grow. One of the most promising are quantum dot displays (QLEDs). A quantum dot is a microscopic piece of semiconductor in which quantum effects begin to play a significant role. A simplified radiation process looks like this: exposure to a weak electric current causes the electrons of the quantum dots to change energy, emitting light. The frequency of the emitted light depends on the size and material of the dots, making it possible to achieve almost any color in the visible range. Scientists promise that QLED matrices will have better color rendering, contrast, higher brightness and low power consumption. Quantum dot screen technology is partially used in screens Sony TVs, and LG and Philips have prototypes, but there is no talk of widespread use of such displays in TVs or smartphones yet.

It is also highly likely that in the near future we will see not just curved, but also completely flexible displays in smartphones. Moreover, prototypes of such AMOLED matrices almost ready for mass production have existed for a couple of years. The limitation is the electronics of the smartphone, which cannot yet be made flexible. On the other hand, large companies can change the very concept of a smartphone by releasing something like the gadget shown in the photo below - we can only wait, because the development of technology is happening right before our eyes.

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 a smartphone with a good matrix, while maintaining reasonable 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. That's why now the majority inexpensive smartphones, the screens of which are designated as OGS, are actually equipped with modules manufactured 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.

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