E4 material, HDR 10+… How much do you know about the screen parameters of mobile phones?

Screen is the main window of human-computer interaction. The quality of the screen almost determines the user experience of the mobile phone.

Fortunately, since the iPhone 4 started the trend of "retina screen", more and more manufacturers began to pay attention to the user's visual experience. The screen size is bigger, the border is narrower, and the bangs are smaller ... these are not enough. At the launch conference of new machines in the past two years, manufacturers began to emphasize the parameters such as material, contrast and color of the screen.

For example, Xiaomi 1 1 series, known as "flagship machine goalkeeper of 202 1", has made great efforts to improve the screen quality: Samsung E4 material, 5000000: 1 contrast, 1500nit maximum brightness, 2k+. Lei Jun said that this is "the most expensive and best screen in the history of Xiaomi mobile phone".

Xiaomi 1 1 screen poster

In the iOS camp, the super retina XDR screen on the iPhone 12 series supports playing Dolby Vision video and HDR display, which once again refreshes the look and feel experience of the iPhone. Apple called this screen a "sea of pixels" in official website.

Although manufacturers are vigorously promoting, these figures and proper terms are still somewhat difficult for ordinary users to understand. We try to analyze the screen parameters of these two "benchmark phones" in plain language, whether they are gimmicks or real kung fu.

Based on Xiaomi's mobile phone official Weibo and official website, as well as Apple's press conference and official website's publicity, we can see that their publicity points on screen quality mainly include the following aspects.

Let's look at "luminescent materials" first. One of the characteristics of OLED screen is that each pixel can emit light independently without backlight. Therefore, luminescent materials greatly affect the power consumption and display effect of the screen.

E4 used by Xiaomi 1 1 is Samsung's latest organic light-emitting diode luminescent material. Compared with the previous generation E3 materials, the main upgrade points of E4 are peak brightness, contrast and power consumption. For example, the local peak brightness of Xiaomi 1 1 soared to 1500nit, the contrast was upgraded to 500000: 1, and the power consumption was reduced by 15%.

Although the whole system of iPhone 12 also uses organic light-emitting diode screens, there is no official information about its luminescent materials at present.

Then let's look at "resolution" and "pixels per inch". The resolution of the screen refers to the number of pixels displayed on the screen, which is generally expressed by horizontal pixels and vertical pixels. At the same size, the higher the resolution, the more delicate the impression, which involves pixels per inch.

Jobs first proposed the retina screen at the iPhone 4 conference, indicating that the iPhone 4 has 326ppi pixels per inch, which exceeds the human eye recognition limit by 300ppi.

But this definition is conditional, that is, the user's vision is 1.0, and the viewing screen distance is 20-30cm. In fact, some people's eyesight may be higher than 1.0, and the screen will be closer to the human eye. According to the data of the shell network, the actual resolution of most people's eyes should be as high as 450ppi or more.

Xiaomi 1 1 and iPhone 12 Pro Max have pixels per inch higher than the value of 450ppi. If you don't look at it with a magnifying glass, it is difficult for the human eye to detect the difference in fineness between the two.

Image from: eizoglobal

"Contrast" and "peak brightness", we mentioned the screen luminescent materials above. The so-called "contrast" is actually the "light and dark performance" of the picture. The common expression is xxxx: 1, such as 2000000: 1. The higher the previous value, the higher the contrast.

Higher contrast means that you can see more light and dark details on this screen. For example, the following two pictures are typical contrast test pictures. The better the screen contrast, the more clearly you can see the squares behind. If the contrast is not high enough, it may be dark or pale.

White test. Image from: glennmessersmith

Black test. Image from: glennmessersmith

So what does "peak brightness" mean? It means that there can be how bright under the screen limit, and the unit is nit. It should be noted that the peak brightness of Xiaomi 1 1 1500nit and iPhone 12 Pro Max 1200nit refers to a part of the peak brightness, not the whole screen.

In addition, we should understand that the peak brightness is equivalent to a 100-meter sprint, which will not last long, and there are many conditions for activation. The higher the value, the more helpful it is to restore the HDR scene.

This has to mention "high dynamic range". Xiaomi 1 1 supports the dynamic range of HDR 10+, and iPhone 12 supports Dolby Vision video and HDR display.

At the top is Xiaomi 1 1, and at most, only "HDR field of vision" can be opened; The following is iPhone 12 Pro Max, which supports Dolby Vision.

Earlier, we had an article that specifically introduced what Dolby horizon is and its advantages over HDR 10 and HDR 10+. Simply put, Dolby Vision is the HDR video standard with the highest requirements for parameters on the market at present, and it needs to pay a lot of licensing fees. And HDR 10+ is an open specification, which is the mainstream choice at present.

The impact of this on ordinary users mainly lies in the experience of watching videos. Some platforms such as iQiyi and Tencent Video already support Dolby Vision format. Watching such a video, the experience of iPhone 12 Pro Max will be a flight of stairs.

The following is the effect of iPhone 12 Pro Max opening "Dolby Vision", with richer picture layers.

I believe everyone is familiar with the "refresh rate" and "touch sampling rate" mentioned below. The mainstream smartphone screen refresh rates are 60Hz, 90Hz, 120Hz, which can be understood as how many frames can be displayed on the phone screen in one second.

The larger the number, the smoother the visual experience will be when moving pictures, especially when sliding pages. Of course, the price is that the screen consumes a lot of power and the battery life of the mobile phone will be affected.

At present, the more advanced solution is to use LTPO (Low Temperature Polycrystalline Oxide) panel to realize several variable refresh rates on hardware, or to set several variable refresh rates through software optimization. However, the hardware of Xiaomi 1 1 does not support LTPO, only 60Hz or120 Hz; Can be selected in the settings; IPhone 12 Pro Max only supports 60Hz.

Xiaomi 1 1 screen refresh rate option

The "touch sampling rate" is the number of times that the screen can perceive your finger movement in one second. The higher the value, the more sensitive the screen and the more sensitive the manual tracking. For game lovers, especially music lovers, this value is more important.

In the publicity column of Xiaomi 1 1, "8 192 level dimming" is also an important parameter, which we have seen on one plus 8T. Compared with "4096 level dimming", 8 192 level means that the brightness level of the screen has more gears. Especially in the automatic brightness mode, the brightness change of the mobile phone screen will be more delicate and smooth.

But this is only a theoretical analysis. In fact, the brightness change of the screen has a great relationship with the sensitivity of the mobile phone light sensor and the optimization of the algorithm. Numbers can only be used as a reference, and the actual experience is not up to them.

Screen comparison between iPhone 12 Pro Max (left) and Xiaomi 1 1 (right)

Screen parameters often mentioned by mobile phone manufacturers are color gamut, color accuracy and color depth.

Simply put, color gamut refers to the range of colors that can be displayed on the screen. At present, P3 and sRGB color gamut are the mainstream. For example, the default setting of iPhone 12 Pro Max and the adaptive mode of Xiaomi 1 1 are all P3 color gamut. Xiaomi also provides two other modes: sRGB color gamut in primary color mode and NTSC color gamut in bright color mode.

At present, mainstream flagship machine has done a very good job in color gamut coverage. The data of WHYLAB test shows that the color gamut of Xiaomi 1 1 covering P3, NTSC and sRGB exceeds 100%. The default P3 color gamut of iPhone 12 also exceeds 100%.

The wider the gamut coverage, the richer the colors. Image from: Youpai

Color accuracy may affect our perception more than color gamut. Color accuracy refers to the accuracy of color. Xiaomi 1 1 refers to "professional primary color screen", which means that this screen is very accurate in color reproduction.

Xiaomi also gave specific values in official website: JNCD 0.38；; Delta E0.41.iPhone12 PROMAX did not indicate relevant parameters, but according to the data of displaymate, its average color error is 0.9 JNCD, which is also an excellent level.

We don't need to delve into the algorithms of JNCD and Delte E, only need to know that these two parameters refer to "the difference between two colors that human eyes can perceive". The smaller the value, the better, indicating that the screen can restore colors more accurately.

In P3 color gamut, iPhone 12 Pro Max (left) and Xiaomi 1 1 (right) have different color tendencies.

Finally, let's look at the color depth. Color depth is simply how many colors you can call in the same frame, and the unit is expressed in bits. The darker the color, the better. For example, 8bit has more colors than 6bit, and 10bit is better than 8bit.

It can be understood that from big red to deep red, the greater the color depth value, the more transitional colors between the two colors. When we look at photos and videos, we will feel that the color transition of the picture is more natural.

10 bit contrast 8 bit color depth indication. Image from: Jack Forest

In addition to the screen parameters often mentioned by the above manufacturers, Xiaomi 1 1 and iPhone 12 series also emphasize the glass material.

Xiaomi 1 1 adopts the seventh generation glass Victus of Corning Gorilla. Corning said that this generation of glass has improved its fall resistance and scratch resistance. The fall resistance is 1.5 times that of the previous generation, and the scratch resistance is improved by 2 times.

In fact, this generation of glass named Victus was first introduced in Samsung note 20 ultra. According to the test of tubing blogger Zack Nelson, the screen of Samsung note 20 ultra began to scratch at 6 Mohs hardness, and deeper grooves appeared at 7 hardness.

Scratch resistance test of Note 20 ultra. Image from: Zach Nelson

Using Xiaomi 1 1 with the same glass, the scratch resistance should be evenly matched with Samsung note 20 ultra. However, our streaking millet 1 1 has some scratches, so it is better for friends who mind to stick a layer of toughened film.

IPhone 12 adopts "super porcelain crystal glass panel". Apple said that it cooperated with Corning to combine nano-scale porcelain crystals with glass through the "double ion exchange process". However, the hardness of nano-ceramic crystal is higher than that of most metals, so the hardness of super-ceramic crystal panel is much higher than that of previous glass panel, and the fall resistance is improved by four times.

IPhone 12 Pro Max advertising language

The double ion exchange process also contributes to the scratch resistance and scratch resistance of glass. However, the screen of iPhone 12 Pro also began to scratch under the "difficult hand-damaged flower" of tubing blogger Zack Nelson, and the scratch deepened at 6 Mohs hardness, which looked similar to the performance of Victus.

Scratch resistance test of iPhone 12 Pro Max. Image from: Zach Nelson

For many users, whether the screen is durable may be more meaningful than pursuing parameters such as contrast and dimming degree. After all, the cost of changing a screen is getting higher and higher, and wear resistance and fall resistance are king.

Through the screens of Xiaomi 1 1 and iPhone 12 series, we can also infer the development direction of flagship machine in 20021year.

In terms of hardware, E4 will replace E3 luminescent materials and be applied to more flagship machine. This brings higher screen brightness and better outdoor experience. The screen resolution will be based on 2K. If flagship machine still uses the screen of 1080P, there is a high probability that someone will spit it out.

In 2020, the screen refresh rate has become a competitive selling point in flagship machine. This year, we may pay more attention to the improvement of touch sampling rate.

The automatic adjustment of screen brightness may also become the next force point. When we mentioned auto brightness before, we would be full of praise for the screen of iPhone. However, with the attention of Android manufacturers, iPhone's achievements in this area will face more challenges.

The screen is getting better and better and the maintenance cost is getting higher and higher. It takes one or two thousand to change a screen, which makes consumers expect the durability of the screen to be enhanced. And Corning Gorilla's seventh-generation glass Victus may be one of the best solutions for Android camp at present.

Slogans such as Xiaomi 1 1 "Professional Primary Color Screen" also show us flagship machine's efforts in color accuracy. In the past, we took different photos with the naked eye on different brands of mobile phones or different devices of the same brand, mainly reflected in the color difference.

Under the default settings, the perception difference between iPhone 12 Pro Max (left) and Xiaomi 1 1 (right).

This is not only because of the different screen hardware quality, but also because of the lack of color management system.

At present, only Apple has a relatively complete color management system. As early as 7. 1993 on the system1MAC, the technology of "ColorSync" has been applied. Starting early and attaching great importance to it have created the color uniformity of Apple devices.

In the Android camp, OPPO is about to apply "full link color management system" to Find X3 series for the first time, which is also the first full link color management system in Android.

It can be predicted that in 20021year, the screens in flagship machine will be in full swing. And if you master the meaning of the above parameters, you can happily "eat melons and watch plays".