What is a good screen, or what qualities should fans choose from? Today, I will tell you something about the screen.

This issue of popular science is not only applicable to notebook computers, but also to desktop monitors. For the convenience of example, we take a monitor located in a professional media manufacturer as a reference, and introduce the meaning behind the parameters of the monitor from the simple to the deep.

First of all, let's briefly introduce the specific parameters of the display in the control group:

27 inch 4K(3840×2 160) resolution, 99%AdobeRGB color gamut IPS panel, interface, this monitor has 2 HDMI, 1 DP, 1 miniDP, 3 USB downlink interfaces, 1 USB uplink interface and/kloc-0.

The actual test results are as follows: the color space basically covers sRGB and AdobeRGB, and the color gamut coverage of DCI-P3 is over 90%. The average Delta E is 0. 1 1, and the maximum is 1.98, which can be said to be quite good.

In terms of uniformity, the measured center of the display can reach about 340nit, which is close to the nominal maximum brightness (350nit), and the corners are only 280nit, which can only be said to be unsatisfactory.

The control group showed the measurement of uniformity.

In addition to excellent color display, this control group monitor also has good expansibility. The manufacturer has equipped this 60W monitor with 180W adapter, so that the USB Type-C interface of the monitor can not only be used to transmit video signals and data, but also be used to charge the notebook supporting Type-C power supply.

Anyway, let's get down to business and start this issue of popular science.

1, resolution, aspect ratio and pixels per inch

Almost every computer user knows what resolution means. Whether the resolution can reach 1080P is also the only requirement for most white people to buy a computer. There are also some extreme fans who have no brains to pursue 4K screens when buying high-profile notebooks. What resolution screen should we choose when choosing a daily computer?

When it comes to resolution, we have to mention another concept: aspect ratio, which has a great influence on our daily use habits. In the early days, the mainstream display ratio was 4: 3, and then it gradually developed to the widescreen ratio of 16: 10. Due to the cost of panel cutting, the more cost-effective 16: 9 cutting scheme has gradually become the mainstream of the market. Many products of Apple still like to use the screen of 16: 10, while the Surface series products launched by Microsoft in recent years focus on promoting the 3:2 ratio closer to traditional paper.

Evolution of aspect ratio of display

The resolution is slightly different with different aspect ratios. At present, common display products on the market are classified according to aspect ratio and resolution, as shown in the following table. Except for Surface and Mac series, and 2 1: 9 and larger screen with fish screen, the other three types are full HD 1080P, 2K and 4K screens that are common in our notebooks.

Statistics of aspect ratio, horizontal and vertical resolution of display

In terms of parameters, of course, the 4K screen is the best, but do we really need to use such a high-resolution screen on notebook products? This will introduce the concept of "pixels per inch". PPI refers to the number of pixels per inch. Theoretically, the higher the PPI, the finer the picture. Unfortunately, screen scaling in Windows display settings often leads to blurred fonts in software, and different settings may also cause problems with element scaling in some software. In order to avoid these situations, a better solution at present is to replace all commonly used software with UWP applications or adjust the screen scaling to 100%, which is obviously more universal.

On notebooks, common screen sizes are 13, 15 and 17 inches. Here, we will show you the images taken from the 4K screen at the ratio of 100%. Fans can feel it on their own display devices. These are screenshots of 4K and 100% scale. So if you choose a notebook with a 4K screen, adjusting the screen ratio is likely to become your daily life. Of course, the 4K screen is not useless, because the popularity is still not high. Almost all notebook 4K screens that can be found in the market are high-quality screens, and the same size can display more content, which is also widely favored by media workers.

2. Panel type, viewing angle, response time and refresh rate

The type of screen panel is very complicated. Due to the different patented technologies of different manufacturers, the naming of panel types is also different. Notebook manufacturers generally divide screens into TN and IPS in publicity, and claim that IPS is better than TN. In fact, there is no way to judge the screen effect from the panel type alone. TN panel usually has a smaller viewing angle, faster response time and higher refresh rate, while IPS panel has a larger viewing angle. However, the quality of an excellent TN screen is not worse than the standard deviation of mainstream notebook IPS on the market, and IPS panels can also find e-sports products with high refresh rate and low delay. In addition, the panel type is a factory trademark, and there is no simple way to judge. Therefore, when choosing a screen, the reference value of the panel type is not high, so try to use your own actual perception as the selection criterion.

Visual angle is a concept that is easily used by manufacturers to make a fuss. A real high-quality screen should have the same effect from all angles. But many manufacturers only judge the viewing angle according to whether they can see the picture displayed on the screen. In the evaluation, we even saw IPS panels with worse viewing angles than some TN screens. If you look at them from a slightly biased angle, the screen will have serious color difference. However, there is no accurate and convenient quantitative data from the perspective, and the best way to judge is to experience it personally. It is strongly recommended that major notebook brands and e-commerce platforms provide real photos from all angles of the screen for users to choose from. Regarding the viewing angle, we summarized a convenient detection method for people who have access to the prototype to try: aim your head at one side of the display, the distance to the display is similar to the width of the display, and then turn your head to look at the other side. If the picture displayed above is clear and there is no obvious color cast, then we can think that the display effect of this screen is ok. Try again at the usual distance where you use your notebook. If the far display effect is acceptable, then the viewing angle of this screen.

Response time is a difficult parameter to detect, which is mainly divided into black and white response time and gray response time. The former is the time required to change from black to white, and the latter is the time required for gray scale change. There is no way to directly compare the black-and-white response time with the gray response time. The parameter of reaction time is also very important for e-sports players, because there is no relatively convenient detection method, so it can only be compared by official data. The smaller the response time parameter, the better.

The refresh rate is a very important parameter. Now more and more games test the refresh rate of the screen, and the concept of "e-sports screen" came into being. In some professional fields, a screen with a refresh rate of 30Hz can meet the requirements of users. Our daily common screen has a refresh rate of 60Hz, and "e-sports screen" usually needs a refresh rate of 120Hz or more to meet the standard. So why is a high refresh rate screen so important? Because it can make people feel that the picture moves more smoothly, and the lack of refresh rate will make people feel that the picture jumps, flashes and is incoherent. Generally speaking, the closer to the screen, the larger the screen size, and the higher the requirement for refresh rate. In addition, with the help of G-Sync, Free-Sync and other technologies, the screen with high refresh rate can control the tearing of the picture better. It can be said that the higher the refresh rate, the better when other parameters meet the demand and the budget is sufficient. However, the effect of each refresh rate increase of 1Hz is not obvious, and the effect of 144Hz is much lower than that of 120Hz. If you don't have too high requirements for the fast movement of the screen or the consistency of the screen content, 60Hz can be said to be enough for your daily use.

3. Color gamut, color depth and color accuracy

The following concepts can be said to be the key concepts that determine the quality of a screen and how much Qian Qi should sell. Color gamut, also called color space, can be simply understood as the size of all color ranges that can be displayed on a screen, such as how red red is, how green is, and how blue is. The color depth indicates the fineness of the gradient between colors. Taking gray scale as an example, the more types of gray scale that can be inserted between black and white, the better the display quality. Gamut defines the outer boundary of color, while color depth indicates the inner level.

Commonly used standards to measure the color gamut of displays are sRGB, AdobeRGB, NTSC, DCI-P3, etc. As shown in the figure, each color gamut is not completely coincident, which leads to two new concepts-color coverage and color quantity. The former means that the intersection of the actual color gamut and the control color gamut is always less than or equal to 100%. The latter means that the coverage area of the actual color gamut on the chromatogram may exceed 100% relative to the size of the control color gamut, while the commonly used standard in the pen bar evaluation room is the color coverage of NTSC color gamut. In actual publicity, many brands like to use sRGB as the standard. First, the numbers look good. Second, if the screen color space is really good, the slogan "Gundam 150% standard color gamut" is also quite bluffing. In practice, the Windows operating system has once again held us back. Due to the sRGB color space adopted by Windows itself and the poor color management of the operating system, the display screen will be seriously oversaturated in many application scenarios. However, because many image processing software have their own color management, there is no need to worry about serious color problems in the photos and videos you make under Windows. Apple's products next door are also deeply loved by film and television producers because of the excellent color management of MacOS.

Schematic diagram of size coverage relationship of several basic color gamut

In daily use, 72%NTSC or 100%sRGB screen is enough. Nominally lower than this value, we generally think that the screen quality is poor, 45%NTSC color gamut is considered as junk screen, and many people call it blind screen. In fact, it doesn't mean that using this screen will cause harm to your eyes. If you have very high requirements for photo processing, you may need to print photos, so you need to choose a screen as close as possible to 100%AdobeRGB. Why are you meeting AdobeRGB here? Because AdobeRGB covers the standard CMYK color gamut of printing industry, the display color can cover the color actually output by the printer. Apple users may be more concerned about the DCI-P3 color gamut, and this color gamut standard is also a standard that the film and television industry is more concerned about.

We also mentioned the measurement data of the monitor in the control group. For this high-end monitor specially designed for designers, we should focus on the color coverage of AdobeRGB and DCI-P3. The former is used for graphic production and the latter is used for video output.

The color depth of the display panel mainly includes 6bit, 8bit, 10bit, etc. It should be noted that some displays will use pixel dithering technology to "enhance" the color depth of the display, so that in addition to "picking holes" with gray images, the look and feel will indeed be improved. Generally, we recommend monitors that support 8 bits and higher. It should be noted that in some OpenGL rendering interfaces, such as Photoshop, if you want,

It is a good thing to display more colors, but a good screen should also display accurately. The color scale is used to describe the deviation between the screen display and the actual color, which is usually expressed by δ E. The smaller this value, the more accurate the color display. Most high-end monitors have their own factory color calibration report δ E.

4. Brightness, contrast, high dynamic range and backlight uniformity

The brightness of the screen panel is different, which is usually only used when we often change the working environment or the light changes frequently in the working scene. The stronger the ambient light, the higher the brightness of the display is required. On the contrary, when the ambient light is weak, we should reduce the brightness of the screen appropriately, otherwise it may cause eye discomfort. Generally speaking, the brightness of 350nit can meet the highest requirements of daily use, and the higher-end screen that can be found in notebooks can reach 500nit. Nowadays, many screens claiming to support HDR technology obviously require higher maximum brightness of the screen. HDR technology is to make the picture displayed on the screen closer to the real world with higher contrast, that is, the bright part of the picture is brighter and the dark part of the picture is darker, so the maximum brightness of many display devices supporting HDR can even reach 1000nit. The highest brightness is high, the lowest brightness is low, and the contrast is naturally high. At present, the OLED screen is the best in this respect. Because of its luminous principle, the theoretical contrast of OLED screen can be close to infinity. However, due to various factors, there are very few OLED screen products on the market at present.

The problem of screen light leakage can be said to be a matter of great concern to fans. There are even many buyers who find that there is light leakage on the screen after turning on the phone and go straight for 7 days for no reason. Light leakage is generally a packaging problem of the screen panel itself, or a design defect of some models causes the screen shell to squeeze the panel. Generally, it can be verified by letting the screen display a black screen and watching it directly. If the light leakage area is not large enough to affect the display effect of color pictures, it can be used completely. Many small white users pay too much attention to light leakage after buying a new machine. Actually, it is a misunderstanding. We usually suggest putting the parameters such as viewing angle, color gamut and color accuracy in a more important position. Only when these items meet the requirements can we consider the light leakage of the screen.

5. Matters needing attention when purchasing monitors

For those friends who want to buy a desktop monitor, there are still some things that need your attention, such as the monitor interface. For ultrabooks that can be charged with USB Type-C, when purchasing an external screen, you can consider a display with a Type-C interface, such as our control display. When using Type-C connection, there is no need for an external adapter, which effectively reduces the messy wires on the desktop. However, it should be noted that it is not recommended to turn on the data transmission function in Tpye-C of some monitors. Because of the bandwidth limitation, when the data transmission function of Type-C is turned on, the refresh rate of the display will be reduced to 30Hz by default. For ordinary users, it is recommended to choose a display with both DP and miniDP interfaces. Due to different designs, DP interface has better performance than HDMI of the same generation, and different computers may be equipped with different models of DP interfaces. A display that supports both DP and miniDP only needs one video transmission line, which is more compatible. For the host player, HDMI interface is essential. Due to market policy reasons, HDMI is more popular than DP, while PS4, XBOX and other game consoles only support HDMI, and displays with HDMI interface are obviously more convenient. DVI and VGA interfaces are not recommended. Unless you want to dig out the old machine 10 years ago, these two interfaces that have long been eliminated can still be used. After all, even DVI was cancelled on Volkswagen GTX 1080Ti. Public version 1080Ti cancels DVI interface.

6. Summary

That's all the popular science about the screen. To sum up, the screen is actually a relatively metaphysical thing. Just looking at the parameters, there are many consumption traps. The best choice is the actual experience. Only when you have experienced it yourself will you know whether this screen is suitable for you. For users who can't experience it personally, we can only recommend it according to different usage scenarios and with relatively reasonable judgment criteria:

For users who work in the office and read text all the year round, you should start with the visual angle and the maximum brightness of the screen. If you have outdoor office needs, you may need to consider the frosted screen as the first choice. Generally, you should choose a notebook, just choose 1080P IPS screen.

For friends who usually watch movies online, I recommend you to choose IPS screen with 72%NTSC color gamut.

For users with design requirements, drawing details or editing video clips, we recommend that you choose a screen with a resolution of over 2K, and the minimum color gamut requirement is 72%NTSC. If possible, please choose AdobeRGB or DCI-P3 color gamut standard, and the higher the value, the better.

For users who need e-sports, especially the first-person shooter, I suggest you pay attention to the parameter of refresh rate. The higher the refresh rate, the better. For example, if your computer eats chicken, it can run to 100 frames per second. The screen you choose is not much different from the screen you choose, but if you play CS: Go, you can run to it.

If you are a local tyrant, you just want to buy a top-level external monitor to play with. Some people recommend you a screen with DVI interface, most of which are just teasing you.

So much for the popular science of the screen today. If you have more questions about the screen, please reply to the message. If necessary, we will select some valuable questions and hold a special issue of popular science to answer them for you. If you think our popular science content in this issue is of reference value to you or your friends, please tell us and forward it to the collection. If you still want us to launch more similar popular science content, you are welcome to leave us a message. And welcome everyone to pay attention to our official Weibo WeChat, Zhihu column and live broadcast platform. If you are not satisfied with your current notebook screen, please also consult our official maintenance Taobao shop. If you feel bored watching videos, you are also welcome to come to our snack bar to find something to eat. All platforms can search for pens, evaluation rooms.

Exchange your screen selection experience and help the computer. That's all for this issue. See you next time!