What is the difference between smartphone screens? Everything you need to know about types, resolutions, and frequency

When it comes to smartphone screens, there are many parameters that describe them. But it is not so easy to understand so many abbreviations and numbers. This article will help you navigate when choosing a smartphone, if the parameters of its screen are really important to you. Full HD or 2K, LCD or AMOLED? What is 300 ppi and 2160p? The answers to these and other questions can be found below.

Resolution One of the main parameters of smartphone screens is their resolution. When it comes to resolution, specify the size of the screen diagonal in inches, the number of pixels, and how tightly packed they are (pixels per inch, or ppi).

If you know the size of the display, you can determine how many pixels fall into one square inch: this is the pixel density (ppi). If you want, you can easily calculate the ppi of your phone, armed with a calculator.

So, the main screen resolutions of modern smartphones:

< /p>HD

< /p>HD stands for high definition or high resolution. If we talk about the number of pixels, the HD screen contains 1280 x 720 pixels, regardless of its size.

Naturally, the smaller the screen, the higher the pixel density and, theoretically, the better the image. Therefore, the very presence of an HD display does not matter much, since on a 5-inch screen, the picture quality will differ from the same on a 10-inch screen.

For example, a 4.3-inch screen has a pixel density of 342 ppi. On a 4.7-inch screen, the pixel density will drop to 312 ppi, but both will remain HD displays. According to Apple, 300 dpi is the best option, since this is about the point at which the human eye stops distinguishing individual pixels at a certain viewing distance (and on a screen of a certain size).

Full HD

Full HD resolution has been the next step in improving smartphone displays and is now the standard, although 2K (QHD) has been gaining popularity on high - end devices since the Oppo Find 7 and LG G3, the first commercially available devices with QHD screens.

Full HD is 1920 x 1080 pixels. Again, their density will depend on how large the screen is. In smartphones with a diagonal of 5 inches, the pixel density is about 440 ppi, and on a 5.5-inch screen, it drops to 400 ppi.

< /p>QHD, Quad HD or 2K

QHD means Quad HD, which is four times more than the standard HD resolution, or 2560 x 1440 pixels. The 5.5-inch QHD display has a density of 538 ppi.Very often, the HD resolution is called 720p, Full HD-1080p, and so on. As for QHD, its second name 2K comes from the fact that the number of pixels of such a screen in height is more than 2000 (although, in fact, 2.5 K should be mentioned, to be perfectly accurate).

Many phones from Samsung, Motorola, Huawei and other well-known brands are now equipped with 2K displays as standard.

4K or Ultra HD

Like 2K, the name 4K comes from the number of pixels in height – here they are 4096, but in Ultra HD-only 3840. Thus, although the two terms are often used in place of each other, they are still slightly different.

The Ultra HD screen measures 3860 x 2160 pixels, and the 4K screen measures 4096 x 2160. Often both of these resolutions are referred to as 2160p. One of the first phones with a claimed 4K display was the Sony Xperia Z5 Premium, which offered Ultra HD resolution on a 5.5-inch screen.

Sony called this display 4K, although, in fact, its actual resolution is slightly smaller. However, the Z5 Premium has a pixel density of 806 ppi – which is much more than many smartphones offer, and even beyond what users consider necessary.

Trend While smartphone screens continue to increase, devices with 4K displays are not as common. Therefore, Sony continues to lead the way in this area with the Xperia Z5 Premium and XZ Premium models.

As a result, 2K screens have become the norm for phones. It is likely that this has a direct bearing on the question of the battery life of the device, since large displays with high resolution consume much more power. Since battery life has become a hot topic for many smartphones, manufacturers seem reluctant to move towards 4K.

< /p>Panel types Smartphones use different types of displays: LCD, OLED, AMOLED, Super AMOLED, TFT, IPS, and the rarer TFT-LCD. Recently, IPS-LCD panels are among the most common. But what do all these abbreviations mean?

LCD

LCD or Liquid Crystal Display means a liquid crystal display whose matrix is created using liquid crystals with backlight. The relatively low cost of such displays makes them popular with manufacturers of phones and other equipment.

LCD screens, as a rule, work quite well in the bright sun, since the screen itself is illuminated from behind, but, unfortunately, they also have disadvantages-less accurate color reproduction.

In smartphones, TFT and IPS displays are often found. TFT is short for Thin Film Transistor-a screen that uses thin-film transistors, in other words, an improved version of an active matrix LCD (like AM in AMOLED). The concept of an active matrix means that each pixel is connected to a transistor and a capacitor separately.

The main advantage of TFT is its relatively low cost and increased contrast compared to traditional LCDs. The disadvantages of the TFT LCD are higher power consumption than other types of LCD screens, less impressive viewing angles and not too accurate color reproduction. It is for these reasons that TFT displays are increasingly used in smartphones.

IPS stands for In-Plane Switching, and this is an improved version of the TFT LCD. This display provides better color reproduction and, most importantly, a wider viewing angle. This is achieved by using two transistors for each pixel, combined with a more powerful backlight. The disadvantage is the high power consumption. But, as a rule, IPS screens still consume less power than TFT.

There are other types of abbreviations that can be found in combination with IPS, for example, IPS-NEO. In this case, it is the brand name of the technology created by JDI, but it works the same way as in any other IPS-LCD display.

AMOLED

AMOLED (Active Matrix Organic Light-Emitting Diode) stands for organic light-emitting diode with an active matrix. The name may seem complicated, but it really isn't. The active matrix works here, as in in the TFT LCD technology, and OLED is just a term for another thin-film display production technology.OLED is an organic material that, as the name suggests, emits light when a current passes through it. Unlike backlit LCD panels, OLED displays are "always off" if no power is applied to individual pixels.

This means that OLED displays have a much cleaner black color and consume less power when black or darker shades are displayed on the screen. However, the lighter themes on AMOLED screens consume significantly more power than in LCDs. OLED screens are also more expensive to produce.

Since the black pixels on the OLED display are "off", the image contrast is higher compared to LCD screens. AMOLED displays have a very high refresh rate, but on the other hand, the picture on them is not as clearly visible in direct sunlight as on backlit LCD displays. Screen burnout and degradation of diodes (don't forget that they are organic) are also factors that need to be taken into account.

On the other hand, AMOLED technology allows you to make screens thinner than liquid crystal (since they do not require a layer with a backlight), and also make them flexible.

What is the difference between OLED, AMOLED and Super AMOLED?OLED stands for organic light-emitting diode. The OLED display consists of thin sheets of electroluminescent material, the main advantage of which is that it produces its own light and therefore does not require a backlight, which reduces power consumption. As mentioned above, AM in AMOLED stands for Active Matrix, which is different from the passive OLED matrix, which is less common in smartphone screens.

Super AMOLED is the name that Samsung has given to its displays. Previously, this could only be found in high-end models, and now in more modest devices. As with IPS LCD screens, Super AMOLED improves on AMOLED technology by integrating the sensor into the display itself, rather than placing it as an additional layer on top.

As a result, Super AMOLED displays perform better in bright light conditions than AMOLED displays, and they also consume less power. As the name suggests, Super AMOLED is just an improved version of AMOLED.

< /p>Retina

< /p>Retina is another marketing term, this time from Apple. The Retina display does not have any particular characteristic, except that it has enough resolution that the human eye cannot distinguish pixels at a normal viewing distance, and has a pixel density of more than 300 per inch.

Given that 5.5-inch QHD screens are already widespread in top-of-the-line Android smartphones, and some devices show a density of 534 ppi, Apple had to eventually capitulate with the theory that 300 ppi is quite enough. As a result, the latest iPhone models, XS and XS Max, have displays with a density of 458 ppi.

Refresh rate: what do 60, 90, and 120 Hz mean?

At the end of 2019, we witnessed how smartphone manufacturers began to actively offer devices with screens with a refresh rate of 90 Hz. OnePlus was the first to use this technology in the OnePlus 7 Pro, and later in the 7T and 7T Pro. Google has released its Pixel 4 and Pixel 4 XL smartphones with the same screens. But what does it really mean? Is there a difference between the standard smartphone frequency of 60 Hz and the flagship 90 Hz? Yes, it is.

The refresh rate shows how many times the display refreshes the image in one second. It is measured in hertz (Hz). A 60 Hz refresh rate display will display picture changes 60 times per second, and a 90 Hz display will display 90 times per second. In essence, this means that the higher the refresh rate, the smoother the image of fast-moving objects looks. Higher refresh rates mean less blurring when moving, and this is important when we quickly scroll through a picture on the screen or play.

So far, 90 Hz is the highest screen refresh rate in smartphones, but Samsung is rumored to launch the S20 series with 120 Hz screens. It is reported that Apple is also working on the production of displays with a high refresh rate.

The disadvantage of 90 Hz screens (and 120 Hz, among others) is that the battery life of the device is significantly reduced.

Screens of the future As we see smartphones moving towards 4K, large TV screens and computer monitors are moving towards 8K (7680 × 4320). The new technology for smartphone screens , meanwhile, may be micro-LED.

< /p>Micro-LED

< /p>Micro-LED or micro-LEDs is a new technology that is still in its infancy, but it has great potential for the display market. Micro-LED screens work similarly to OLED panels, but they are even thinner. They consist of inorganic semiconductors, in particular, gallium nitrite compounds. Like OLEDs, these are also LEDs, but much smaller.

The backlight for micro-LEDs is not needed, and the polarizing filter is also not required. The layer of glass above the panel can be made even thinner. The brightness level of micro-LED is higher per watt than that of OLED panels, and significantly exceeds the LCD. At the same brightness, a micro-LED display consumes half as much power as an OLED screen. Extremely small diodes also allow for higher resolutions – for example, a smart watch with a 4K screen resolution would be quite possible if micro-LED technology was used. Last but not least, micro-LED screens are not as prone to pixel burnout as OLED displays.

The main disadvantage of this technology at the moment is its cost. The production of micro-LED is quite complex, there are very few production lines for this, and the level of defects is still high. All this increases the costs. However, many of these problems can be solved by mass production when it can become so.

Which screen is better?

As you can see, the difference in manufacturers has also created a difference in terminology, although recently these lines have been erased. AMOLED screens are no longer always just Samsung's, and Retina isn't always used by Apple. LCD displays for the iPhone are currently manufactured by LG, while Samsung produces screens for the iPad.

In general, when comparing screens, it is necessary to take into account not only the numbers and manufacturing technologies, which we discussed above. When choosing a smartphone with the best screen, you need to see it in real life to understand whether its color rendering is too cold or warm, whether you like its saturation, brightness or contrast, what its viewing angles are, and so on.

Finally, you should consider your habits: if you spend at work, indoors, all day and relax in the evening, then the benefits of LCD screens that are visible in daylight are probably not so important to you. If you are a fan of outdoor activities and lead a dynamic lifestyle, then on the contrary, LCD screens are what you need.

If you are forced to save battery power or are simply obsessed with stunning colors and contrasts, take a look at AMOLED displays. In a word, the choice is yours.