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Laptop screen

Andrzej Pająk

The screen is the central element of each and every notebook. Things that characterize it are: its size, which also determines how big the whole laptop is going to be, its resolution, and the type of display used.

Size

Most laptops currently on the market have screens that are somewhere between 10 and 21 inches in diameter. The most popular laptops come with screens ranging from 13 to 15 inches.

The size of the screen determines the size of the whole computer. The bigger the screen, the deeper and wider the laptop. However, for the last two years, screens with very thin frames have started appearing on the market. As a result, laptops that at first glance seem to be packing a 13" screen may actually have 14" panels. Gaming laptops with 17" screens packed into 15.6" bodies have also started showing up. An example of a notebook with the biggest possible screen (21") would be the Acer Predator 21X, which came out in 2017 and cost $9,000. But it should be treated as a curiosity, as in the world of gaming laptops the most popular screens have a diameter of 17.3, or 18.4 inches.

More classic designs that combine convenient use with mobility come equipped with 14" panels.

Resolution

Resolution is the parameter that tells us how many pixels are shown on screen. The more tiny squares we have, the sharper, more detailed picture we get. The lowest screen resolution you'll find in laptops currently on the market is 1366x768 (HDl 720p), and the highest is 3840x2160 (4K). However, the vast majority of notebooks come with a Full HD panel, so we get 1920 pixels horizontally and 1080 pixels vertically (1080p.)

PPI

Pixels Per Inch. This parameter tells us how many pixels we'll find in one square inch of the screen. For example, the most popular resolution - Full HD - on a 17.3" screen will have a ppi of 127, but the same resolution on a 13.3" panel will bump the ppi count up to 165.

HiDPI

The higher the resolution, the more information can be displayed on screen. It's a very sought-after feature, but only to a degree. MacBook screens, for example, have a resolution of 2560x1600. Such a high resolution on a 13.3" screen lets us see more, sure, but menu bars may be too small for us to comfortably read them. That's why outside of, let's say, watching films, the resolution is used in a different way. Instead of giving us more workspace, the 4 million pixels are used to improve the sharpness of the picture. Apple started this trend with their Retina displays, where instead of the native 2560x1600 resolution on a 13.3" screen, we get a 1280x800. It gives us a very dense (227 ppi), and clear picture, which is especially visible on thin, curved edges.

Display type

Hardware producers don't always inform what type of panel is used in what laptop, but when we're buying a new computer it's better to look for that information on our own, for example by reading detailed online reviews, as it directly influences the picture quality we will get.

TN (Twisted Nematic) is the most popular - because it's also the oldest and the cheapest to produce - type of TFT (thin-film-transistor) panels. It's characterized by its poor colors when viewed from an angle, mediocre contrast, and passable to good color reproduction (faint saturation). Paired with LED backlight TN screens offer good brightness, but their main asset is the fastest response time on the market, which makes them great for gaming.

IPS(In-Plane Switching TFT) – their main asset when compared with TN panels is their decidedly superior color reproduction and far better viewing angles. One drawback, especially in the cheaper IPS panels, would be their far-from-great black reproduction and contrast, but the more expensive ones can be so good, that even graphic designers use them for work. IPS panels have longer response times than TNs, but there are IPS monitors on the market that need only 4 ms to shift between colors.

VA (Vertical Alignment TFT) – MVA and PVA panels classify somewhere between TNs and IPSs. They have good viewing angles, better contrast and blacks. Theoretically their response times can go lower than what IPS panels have to offer, but, as often is the case, what looks good on paper, isn't what we get in real life (problems with ghosting.) Their colors aren't as good as IPS's.

OLED (Organic Light Emitting Diode) – OLED panels use light emitting diodes as pixels instead of LED backlit liquid crystals of an LCD panel. Each pixel of an OLED panel has its own independent light source. OLED screens are more efficient, and have incomparably better contrast (very deep blacks and amazingly vivid colors) than any other currently existing technology.

IGZO (Indium Gallium Zinc Oxide) – it's not a different type of panel, but the transistors used in it. It can be applied to any type of panel. The difference between a TFT IPS screen and an IGZO TFT IPS screen is that the second one consumes dramatically less energy (80-90%) and thanks to how densely the pixels are packed, it can be used in 4K screens. They can be found in ultrabooks, that value mobility and long battery life more than anything else.

Refresh rate and response time

The standard refresh rate of 60 Hz is enough for practically everyone except gamers. Watching someone play an action game can be compared to, let's say, watching a football match, or better yet, a 100 meter dash on TV. Every time there's a lot of fast movement watching it on a screen with a lower refresh rate means we may encounter some ghosting (trails of pixels behind fast moving objects). Smooth, flowing picture can be achieved with higher refresh rate, like 120 Hz or 144 Hz.

For gamers, a panel's response time (meaning how long does it take it to change a pixel from, for example, white to black) is also important. The quicker the response, the faster the changes on screen, which also means less ghosting. Gamers should aim for screens with a response time of less than 5 ms.

Screen finish

Your notebook's screen can have a glossy or matte finish. In the first case the display comes with a layer of polarized glass which makes the picture look clearer. Unfortunately it's also very reflective and glary, which can be especially cumbersome when using the computer outdoors, or in an office space, where there's a lot of artificial lighting (fluorescent lamps) just above our heads, or behind us.

Matte screens are free of this problem, as instead of reflecting light, they diffuse it. Their drawback is a less vivid and sharp picture.