Properties characteristic of amoled matrices. How comfortable is the Huawei Mate X in terms of thickness? Responsiveness of the XYplorer program developer

Samsung Company differs from other manufacturers in that most of its smartphones are equipped with Super AMOLED screens, rather than the more traditional IPS LCDs. Such displays have become the company's signature feature and have gained many both fans and opponents. These matrices are one of the types of screens based on active LEDs, rather than liquid crystals, and indeed have both advantages and some disadvantages.

Super AMOLED is Samsung's marketing term for its LED matrix displays. last generations, starting in 2010. Such displays initially differed from conventional AMOLED in that they did not have an air gap under the touchscreen. The sensor layer in them is located directly on the matrix, due to which the brightness was increased, power consumption was reduced, the tendency to glare was eliminated, and the risk of dust getting on the matrix was eliminated. Nowadays, most smartphone screens have lost the air gap (except for the cheapest models), including AMOLED, but the term Super AMOLED continues to be used by Samsung.

Super AMOLED displays are built on a radically different principle, unlike conventional LCD matrices. LCD screens consist of an array of liquid crystals, diode backlighting and a mirror substrate. Light passing through the crystals is partially absorbed by them. Depending on the position of the crystal, it glows brighter or dimmer, and transmits only radiation of one color (red, green or blue). The color of the pixel that we see depends on the combination of brightnesses of three multi-colored subpixels.

In Super AMOLED, instead of liquid crystals in the subpixels, miniature LEDs are used, which have the same multi-colored filters. They themselves emit light, the brightness of the glow is regulated by changing the power of the supplied current, using the pulse width modulation (PWM) method. This approach made it possible to abandon additional illumination and a mirror reflective-scattering substrate, which had a beneficial effect on energy consumption and the thickness of the matrices.

Advantages of Super AMOLED matrices over LCD

• Less thickness. The absence of a special mirror substrate, as well as light-absorbing and diffusing filters, makes Super AMOLED thinner compared to its liquid crystal counterparts. This is also facilitated by a sensor installed without an air gap.
• Reduced energy consumption. Since the matrix itself glows (and not its backlight), and the brightness of the picture is adjusted by changing the brightness of individual pixels, less energy is wasted. So, a dark pixel on an LCD panel simply absorbs light, at a fixed brightness level of the main backlight (which still consumes energy), and in Super AMOLED, reducing the brightness of each pixel leads to a decrease in their energy consumption.
• Purer black color. In an LCD, the backlight remains bright, and in order to display black color, the liquid crystals are rotated to a position in which the usual white light of the backlight diodes does not pass through. However, part of it is still scattered, because of this you cannot get perfect blackness: the screen will cast gray, blue or brownish, especially at the edges. On Super AMOLED, when black is displayed, the pixel turns off completely. And since black is the absence of any color, there is nothing to shine.
• Adaptive brightness and high contrast. Depending on the displayed shades and their ratio in the picture, Super AMOLED displays are able to regulate the power supplied. If the screen is completely filled with white, its brightness will not be very high, about 400 cd/m2 (top IPS can have more than 1000 cd/m2). However, if there is a lot in the picture dark shades– light areas become brighter. Due to this, the contrast increases, and in bright sunlight the picture is perceived better.
• Curved screens. The design of LCD panels imposes restrictions on their shape; strong curvature is difficult and expensive to achieve. But LEDs can theoretically be placed on a surface of any shape, achieving a bend with a radius of only a few centimeters.

Disadvantages of Super AMOLED displays compared to LCD

• Price. The cost of Super AMOLED matrices of the latest generations is comparable in price to top-end LCD IPS. However, in budget segment LED panels will be more expensive than LCD panels of similar quality. $5 IPS delivers close-to-natural shades, with possible slight variations in white balance and color temperature. A Super AMOLED panel at a similar price will render overly acidic colors, which is why Samsung doesn't make those anymore. The cheapest Super AMOLED matrix will cost more than its budget IPS counterpart.
• Prone to burnout. Miniature LEDs have limited resource, over time they lose brightness. If the display constantly displays dynamic scenes (for example, movies) - it will simply reduce the brightness over time. But if it always displays some static information of a light shade (on-screen buttons, indicators, clocks, etc.) - in these places the diodes will burn out faster, and over time, “shadows” may remain under them (for example, silhouette of the battery, even if the charge indicator is not shown at this time).
• Flickering PWM diodes. Since the brightness of the pixels is controlled by the pulse width method, they flicker during operation. The flicker frequency ranges from 60 to hundreds of hertz, and those with sensitive eyes may notice it and experience discomfort. The lower the brightness, the shorter each pulse will be, so some people find it unpleasant to look at a Super AMOLED display at brightness levels lower than 100%.
• Pentile. The Pentile matrix structure involves the use of a reduced number of subpixels, usually blue. When used, five (hence the name) rather than six subpixels (one blue and two each red and green) are used to construct two pixels. The use of pentile is driven by the desire to reduce energy consumption, reduce the impact of blue light on the eyes and reduce the cost of producing screens. But at the moment, Samsung creates all matrices using this structure, so when we say Super AMOLED, we mean Pentile. With the naked eye, at the current pixel density, only a few can see the lack of subpixels, but in VR their deficit becomes more noticeable.

Screens with OLED, AMOLED and even Super AMOLED matrix “burn out” over time. If the same pixels are illuminated on the screen for a long time, they will dim and this will be clearly visible. Usually printed virtual buttons navigation, icons in the top bar and a clock. The display cases of smartphones displayed in stores suffer the most from this problem. They are turned on almost around the clock, stand on stands for weeks or months and always show the same demo content, which remains on the matrix forever.

What is causing this problem?

The crux of the problem lies in a key feature of OLED technology. The matrix consists of LEDs of three colors (blue, red and green), and different types diodes have their own service life. Blue subpixels are less bright, so to maintain color balance, they are higher current than the red and green subpixels. Because of this, the service life of blue diodes is reduced, over time they shine dimmer, and the color rendition of the screen goes into red and green shades.

Burnout occurs in the area where blue or White color. Black color does not use the pixel backlight, so it does not cause burn-in. Burnt-in pixels become dark and visible on the screen. The lighter the image, the better they are visible.

Is there a solution?

Manufacturers have not come up with an adequate solution to this problem; they either ignore it altogether or use crutches, providing for periodic displacement of static interface elements operating system by a few pixels. Users may not notice this shift, but it prevents subpixels from overheating and slows down the deterioration of their properties. In some matrices Samsung smartphones PenTile technology is used: blue diodes are larger in size and glow quite brightly with less current, which increases their service life.

How to avoid burnout?

Burn-in occurs most quickly on a bright screen, so you shouldn’t unnecessarily turn the brightness slider to maximum.

Do not leave your smartphone on with a static image for long periods of time.

Use a dark one in applications and keyboards, or better yet black theme registration

If your smartphone supports themes, change them from time to time.

Change the wallpaper and icon layout on your home screen occasionally.

Do not use your smartphone as electronic watch. There are applications that allow you to display the time on the screen, and a few hours of work in this mode is enough for the pixels under the numbers to burn out.

Is it possible to fix a screen with burnt-out pixels?

Diodes do not recover, so it is impossible to remove burnout from the screen. Some people advise leaving the screen in the sun for a couple of hours. After such a procedure, the burnt-out pixels may not be visible, but not because they have been restored, but because the remaining subpixels have also darkened. If your smartphone is uncomfortable to use due to marks on the screen, it makes sense to take it to a workshop and ask them to replace the matrix or do it yourself.

I feel that this year AMOLED vs IPS will be a new trend and a topic for endless debate. I want to express my opinion about AMOLED and IPS screens. I won’t go into technical details, just personal impressions.

Since I used the Galaxy S1, Galaxy S2, Galaxy Nexus, a little Note 2, and also Galaxy Tab 7.7, then I understand perfectly what an AMOLED display is and what its advantages are. In turn, I did not ignore displays on IPS matrices: iPhone 4/4S/5, Meizu MX2, HTC Droid DNA (LCD3) and HTC One(IGZO?).

AMOLED vs IPS

AMOLED screens often use their own pixel structure and most often it's not the best option their layout (PenTile), but in the era of the advent of FullHD resolution in smartphones, you can miss this moment, since it is in AMOLED screens high density pixels can hide all the jambs with a non-standard subpixel arrangement.

Active Matrix Organic Light-Emitting Diode (AMOLED) - technology for creating displays for mobile devices, computer monitors and televisions. The technology involves the use of organic LEDs as light-emitting elements and an active matrix of thin film transistors (TFT) to control the LEDs.

Any display made using AMOLED technology is an advertising bullshield. The colors on such a screen are oversaturated and far from natural, but many people like it, especially at first, until their eyes begin to get tired. To avoid this in smartphones Galaxy lines We added a special item in the screen settings in which you can change the color rendering from “tear out your eye and let him peck the crow” to “dead corpse”. In any mode, the colors are far from natural, I speak as a person who does a little design work.

A.M. OLED screens very economical - advertising noodles for your ears. Indeed, when the smartphone screen displays completely black, the power consumption is minimal, but this does not happen so often. Good example is a browser. If the picture is bright, then AMOLED consumes battery power 5-6 times more actively.

If we compare the power consumption of AMOLED screens with IPS, when white color predominates in the picture, then AMOLED begins to consume twice as much charge as IPS. If we consider the option of displaying icons on the desktop when the background is completely black, then the power consumption in both cases is similar. At normal use Based on the capabilities of a smartphone, a screen on an IPS matrix will always be more economical, unless, of course, you force yourself into limits and use black color everywhere. For Android there is special versions gapps, in which standard applications(gmail, contacts, etc.) are inverted to black colors, even the bare Android interface is mostly made in dark colors. Here you may like it as you please, but the advantages in energy consumption of IPS screens are undeniable.

One of the advantages of AMOLED screens is the maximum viewing angles, but here I can argue with fans of these types of screens. If we take into account the IPS smartphone screens that I listed at the beginning of the article, then their viewing angles are maximum, and in the case of the HTC One there is no distortion at all in the color or contrast of the picture. In the case of AMOLED, the contrast and viewing angles are also maximum, but if you look at a light background, then at certain angles it begins to give off different shades (most often green or red).

The undeniable advantage of AMOLED over IPS is true black color, but every year the quality of black color on IPS screens is noticeably improving, and if you look at it from the point of view that in everyday use of the device we are more likely to encounter light shades on screens than black ones , then the advantage of AMOLED is insignificant.

Which technology is better - IPS or Amoled? We talk about the advantages and disadvantages of screens. How to make the right choice?

There was a time when Samsung loudly declared its Amoled technologies, calling it almost the pinnacle in the production of matrices. Initially, Amoled screens were used in televisions, then the technology was inherited by the brand’s smartphones.

AMOLED displays are not liked for their unnatural picture, excessively high contrast, and saturated colors.

At this moment, the market appears IPS screens with its clarity and natural picture. Which is better - IPS or Amoled, and which display is right for you.

Advantages and disadvantages of IPS and AMOLED

Both technologies have a lot of them, that’s a fact. Let's start with Amoled.

AMOLED – Active Matrix Organic Light Emitting Diode. The technology provides maximum screen brightness and high image contrast, excellent glare suppression in bright daylight/sunlight/lamp light. At the same time, the screen itself consumes little energy, since the pixels are activated only when right moment, while with IPS all pixels are constantly active when the screen is on.

Disadvantages of Amoled:

• High cost of production, which significantly increases the price of a smartphone;
• High vulnerability to mechanical damage;
• Over time, colors fade.

What does IPS have? Here, too, everything is very ambiguous. In-Plane Switching technology was created as an ideological successor to TFT - a frankly outdated technology that does not provide a rich picture, good responsiveness, or wide viewing angles.

Having gotten rid of these shortcomings, IPS became a real godsend. The picture is clear, dynamic, deep and rich. But most importantly, the colors have become truly realistic. Amoled with its oversaturated color palette in this regard it loses greatly. Although, this is also a matter of taste. The picture is clear, the viewing angles are excellent - everything is great.

Disadvantages of IPS:

• Active energy consumption;
• Smartphones with IPS screens are slightly thicker than their Amoled counterparts;
• IPS requires more powerful backlighting;
• Slow matrix response (only the most picky users will be able to tell the difference);
• Pixel grid visibility.

AMOLED or IPS - what to choose?

If you are faced with a choice - to buy a smartphone with an IPS or Amoled screen, start from how exactly you will use it and what you generally expect from the screen. Do you want natural colors and overall good color rendition? Choose IPS. Do you want the battery to last longer, and the picture to delight you with richness and depth? Amoled for you.

At the same time, everyone should remember that you are not buying a TV, but a smartphone. The average user may not notice much difference between these technologies. And perhaps the best advice in choosing is to just look at what you like visually. Well, if you are buying a phone for several years, then it is better to buy one with an IPS matrix. You definitely won't like the faded colors on Amoled. Although, again, you may not even notice them.

I was inspired to create this article by two things: numerous speculations by marketers and specialized journalists on the topic of screens; and a bunch of absolutely identical comment threads under smartphone reviews with absolutely identical discussions about which matrices are better. Usually, the hottest thing happens under the reviews Chinese phones with OLED screens. I’m tired of fighting windmills, communicating with each reader individually, in this material I decided to dot all the i’s and dispel numerous myths about modern screens, looking ahead I will say that the emphasis will be on the confrontation between IPS and AMOLED matrices. Most likely, most of you will not see anything new in what has been written; you will not receive sacred knowledge here, nor will you be stripped of your veils. I will talk about obvious things that neither bloggers nor journalists want to talk about. The guide is designed for adequate thinking people; convinced fanatics can go about their business.

Definition of the term “screen”

Before getting to the point, we need to define the term screen and clarify its functional purpose. Wikipedia tells us that a screen or display is electronic device, designed to visually display information. If we try to give a less laconic and more modern definition of the screen from the point of view functional purpose and with an emphasis on consumer properties, it will turn out something like this: a screen is a device whose task is to display as accurately and in detail as possible all kinds of content and the user interface of operating systems and applications as the authors intended them. Physical resolution is responsible for “maximum detail”, otherwise: quantity smallest elements screen (picture’s elements) or just pixels (pixels), the higher the resolution the better, ideally it should be infinitely large. “As accurately as possible” are responsible for such parameters as: color accuracy and contrast, or the ratio of the lightest and darkest point on the screen. Secondary parameters that do not directly affect the accuracy or detail of information display, but affect the consumer properties of the screen, include: maximum brightness, picture distortion when the view deviates from perpendicular, reflectance, picture refresh rate, response time, energy efficiency and some others . A special parameter is the color gamut - the most important parameter for professional monitors and practically meaningless for devices intended for content consumption. But it is the color gamut in last years is the subject of much speculation by manufacturers mobile gadgets. Let's clear up this murky topic before moving on.

What is color gamut and why is it the subject of much speculation?

You need to start with the fact that any image is encoded when captured and stored in the memory of a photo or video camera. Artificially created pictures and clips, as well as parts of graphic user interface Operating systems and applications are coded in a similar way from the start. In both cases, color information is represented using a color model - a special mathematical tool for describing color using numbers or, more precisely, coordinates. The most common is the three-dimensional RGB model, in which each color is described by a set of three coordinates responsible for one of the colors: red, green and blue; the displayed hue depends on the brightness ratio of each component. Modern screens are capable of displaying only part of the spectrum of colors and shades visible to humans, gamut literally means how big that “part” is. Due to such limitations, a person is forced to create standards for representing the color spectrum based on the possibilities existing screens. So in 1996, to unify the use of the RGB model in monitors and printing, HP and Microsoft developed the sRGB standard, which used the primary colors described by the BT.709 standard, widespread at that time on television, and gamma correction designed for monitors with cathode ray tubes. It is important to understand that such unification allows, albeit with some reservations, to guarantee that the creator and consumer of content on their screens will see approximately the same thing. Subsequently, the sRGB standard became widespread in all areas of content production, including the creation of Internet sites. Of course, there are other standards for representing the color spectrum, such as Adobe RGB, which has a much wider color gamut, but today the vast majority of content is encoded in accordance with sRGB.

What happens if sRGB content is viewed on a screen with a wider color gamut without adaptation? The coordinates of the sRGB space will be transferred to the coordinate system of the color space of such a screen, as a result of which the colors will appear more saturated than they actually are, in some cases the shades will be distorted so much that orange will become red, light green green, and blue blue. Conversely, if content with a wider color gamut is viewed on an sRGB screen, the coordinate shift will cause the colors to appear less saturated than they should be.

We all know that the screens of most modern flagship smartphones have an expanded color gamut relative to sRGB, how does this affect their consumer properties? If this is a smartphone or tablet on Android, then three options are possible. In the best case, the shell settings will contain preset color profiles, among which there is one that brings the space to the sRGB standard, an example would be MIUI or the shell from Samsung. But even in this case, applying profiles on the fly is impossible, and the user will have to choose between an expanded color gamut and correct color rendering. The second option is when the system does not have built-in profiles, but in the developer settings you can activate the sRGB mode, for example this can be done on smartphones Google Pixel and OnePlus 3T. Unfortunately, GUI operating system, when sRGB mode is activated, it becomes faded, as it is encoded in accordance with the color gamut of their screens. In the third worst case scenario, the user will not find any profiles in the system and, accordingly, will not receive any choice; he will be left to enjoy oversaturated colors. But in personal computers there is no such problem on Windows and MacOS, since both systems not only support color profiles, but can also “on the fly” convert colors from one space to another, that is, regardless of what content and on what screen will be displayed, the user with Some reservations will be to see the colors as the author intended them. A similar color profile management system is available in iOS. Manufacturers, either for the sake of beautiful numbers on the specifications page, or just for the sake of it, continue to install in flagship models IPS and OLED screens with an extended color gamut, despite the fact that there is no need for this, since 99% of the content complies with the sRGB standard and it is unlikely that the situation will radically change in the near future. There are simply no tasks that such screens can perform in devices designed for content consumption. All this would make at least some sense if Google added color profile management to Android, as Apple did, but at least in 2017 we won’t see this. The irony is that the problem is created by empty space, and no one is in a hurry to solve it.

Liquid crystal screen: operating principle; Advantages and disadvantages

Twenty years ago, most monitors and televisions were equipped with screens based on cathode ray tubes; they were soon replaced by liquid crystal displays or LCD (liquid crystal display), which over time received several branches of development and today there are three technologies for the production of liquid crystal matrices screens: TN, MVA and IPS, the latter, due to a successful combination of advantages and disadvantages, has become dominant in the segment mobile technology. The operating principle of an LCD is simple, some parts may vary depending on the manufacturing technology, but a typical matrix includes a backlight lamp and six other layers. The first thing behind the lamp is a vertical filter that polarizes the light accordingly. Behind it are two layers of electrodes with a layer of liquid crystals located between them; the voltage applied to the electrodes orients the crystals and they refract the light so that it passes or does not pass through the next layer - a horizontal polarizing filter. The last one is a color filter - red, green or blue. Liquid crystal screens are lighter, more compact and more energy efficient than their predecessors, but they also have a number of serious drawbacks, in particular low contrast and black depth, and even limited color gamut potential, which depends on the imperfection of the backlight. In addition, brightness and contrast may deteriorate if you look at the screen at a different angle.

Organic LED screen: advantages, disadvantages, PWM, Pentile

Relatively recently, LCD has a serious competitor - these are screens with active matrix organic light-emitting diodes or AMOLED. Such screens are fundamentally different from LCDs in that the light source in them is not a backlight lamp, but each subpixel separately, which gives AMOLED many advantages over liquid crystal screens, the main ones being: almost infinite contrast; less power consumption when displaying images with a predominance of dark tones; potentially wider color gamut; and smaller dimensions. The first AMOLED screens, in addition to their advantages, also had significant disadvantages, including: inaccurate color rendering; rapid burnout of LEDs; high power consumption when displaying images with a predominance of light colors; flicker due to pulse width modulation; and most importantly the high cost of production. Over time, most of the shortcomings were overcome or reduced to a minimum, except for PWM, which to this day is the Achilles heel of the technology. Pulse width modulation, or PWM, is one way to adjust the brightness of LEDs, which has the side effect of causing the screen to flicker at a certain frequency. Most people are not susceptible to this kind of flicker, but for some users, PWM can cause rapid eye fatigue and even headaches. It is important to note that the flickering effect is completely absent at brightness values ​​close to maximum and begins to appear at brightness levels of 80% and below.

It is impossible to ignore the topic of organizing subpixels in screens based on organic LEDs; the fact is that in most AMOLED matrices the subpixels are arranged according to the RGBG scheme, when a pixel does not consist of three subpixels like a typical one LCD screen, and of four: red, blue and two green, this scheme is also called Pentile. The manufacturer (Samsung) considers the physical resolution of such screens to be exactly two times less in terms of the number of green subpixels, red and blue subpixels in the matrix. Obviously, to obtain a shade you need at least three full-fledged subpixels. Thus, the effective resolution of such screens is not equal to the nominal resolution specified in the official specification. For example, for a QHD screen the nominal resolution is 2560*1440 pixels, the resolution based on the number of red and blue subpixels will be approximately 1811*1018:

The effective resolution of such a matrix, taking into account the clever interpolation algorithms embedded in the screen controller, is somewhere between 1811 * 1018 and 2560 * 1440, we can assume that it corresponds to FullHD resolution in RGB matrices. It may very well be that it is precisely for this compliance that Samsung has been choosing QHD resolution for its flagship smartphones for many years in a row.

Detailed comparison of IPS and AMOLED using the example of iPhone 7 and Galaxy S8 smartphone screens

Now that we have learned everything about the characteristics of screens and the features of different types of matrices, we can move on to the main question: which technology is better? I am sure it is correct to try to answer this question by comparing best AMOLED And IPS matrices available today, namely the screens of smartphones Samsung Galaxy S8 and Apple iPhone 7. Since I have not yet acquired testing equipment, I will analyze the test results taken from a reputable resource. Let's start with the resolution, the Galaxy S8 screen has 2960*1440 pixels, the guaranteed effective resolution will be 2094*1018, the guaranteed effective pixel density will be 403 per inch. The iPhone 7 Plus has a lower nominal effective resolution: 1920*1080, and an effective pixel density of 401 per inch. The advantage is obvious in favor of the screen from the Korean vendor. The resolution of both screens is sufficient for everyday use and not enough for comfortable use with helmets virtual reality. Next, let's move on to accuracy; the contrast ratio of the Galaxy S8 is almost infinite. The iPhone 7 has a stated contrast ratio of 1400:1, but the actual contrast is slightly higher – 1700:1; this contrast is more than enough for comfortable viewing of content. It turns out that in this parameter the screen of the Galaxy S8 was ahead. As for color accuracy, both smartphones showed virtually identical results; color errors in the Galaxy S8 and iPhone 7 can be safely ignored. You can see the most important secondary characteristics in my opinion below:

As for the color gamut, the iPhone 7 is ahead here, since it can display the colors of the DCI-P3 space or 126% of the sRGB field, while the user does not need to sacrifice color rendition; the content is displayed based on the color profile embedded in it. Galaxy screen The S8 has an even wider color gamut - approximately 142% of the sRGB field, but does not have color profile management, driving the user into a corner, that is, into the Main mode, which corresponds to 100% of the sRGB field.

So what's the bottom line? If we consider screen technologies in isolation from the final product, AMOLED today is superior to IPS in almost everything, although it still has problems with PWM and high power consumption. Without any doubt, OLED matrices are the future. Unfortunately, due to the limitations of Android, their full potential has not yet been realized. When comparing ready-made solutions in the form of Galaxy S8 and iPhone 7, the slight superiority of the latter due to honest DCI-P3 and standard other parameters is obvious. I would like to warn you against projecting the results of the above comparison onto absolutely all IPS and AMOLED screens. There are a lot of good, average and bad matrices on the market, and each case needs to be analyzed separately. Internet publications focused on technical detail and reliability, to such publications I would include the already mentioned, anandtech.com and some other sites, from Russian-language sites - ixbt.com.

Perhaps you shouldn’t take the consumer properties of screens too seriously, because objective information is almost always superimposed on the factor of subjective perception. For example, in Southeast Asia there are a lot of people who like unnatural, oversaturated colors; in our country there are also quite a few such people. On the other hand, broadcasting information poured into the ears by marketers in numerous discussions under reviews on YouTube is at least strange. Finally, I’ll be Cap and give you a couple of banal tips: don’t stop thinking and be critical of any information you receive from brand representatives and the media, know how to analyze data and check facts, or just read resources and watch bloggers you can trust.