While computer monitors seem to be more or less the same once you get past the size and the ports, that’s not really true. Even the most common type, the humble LCD, has a lot of sub-types. And while the differences between them are subtle, they can vary greatly in how they perform and how you use them.
The simple idea of a monitor hasn’t changed a lot since we all moved from cathode ray tubes (CRT) — the big, old-fashioned gray boxes that some of you are too young to remember seeing in real life — to relatively tiny liquid crystal displays (LCD). LCDs have been around for decades, first being paired with simple computer displays way back in the 1970s.
The physics of how they work are fascinating, complex, and frankly too much to cover in an article you probably Googled just to figure out something on a spec sheet. I’m going do my best to bottom-line the most common variants, and why you should know and care about them. I’ll be linking to the relevant Wikipedia articles if you want to do some deep dives on the actual physics behind these displays.
There are three major types of LCD panels used in computer monitors, including the screens built into laptops. These are twisted nematic field effect (TN), in-plane switching (IPS), and vertical alignment (VA).
Twisted nematic LCDs are the oldest type of LCD still in use, with technology iterated since the original digital watch designs decades ago. The name comes from the fact that the molecules of liquid crystal that become electrified are literally twisted by 90 degrees between two glass plates.
Light shines through the liquid crystals and polarization filters, activating the pixel on the screen. Red, blue, and green pixels are combined in a sub-pixel array, and combined at variable brightness to create the desired pixel color.