When I touch my monitor, it starts pulsing dark circles around the spot where my finger is. Why does that happen?
In: Technology
Your screen is composed of multiple layers of material. One of these layers is a grid of liquid crystals (the LC in LCD). Pressing on them deforms them, changing the way they transmit light. Hitting them with electricity also deforms them, which is how they go from opaque to transparent and anything in between.
Your monitor uses something called LCD technology. The way it works basically is that there a light shined on the back of the screen and then the light has to go through different pieces of glass and stuff before it gets to you.
One of the things it has to go through is a sheet of lots of little cells that are filled with liquid crystal (this is where the LC in LCD stands for). These liquid crystals usually act like other liquids, like milk or water, except **when you put electricity through it just right, it can tell light which way to go**!
HOW COOL IS THAT?
but… When you push your finger on the screen you squish the the liquid and now it can’t point light in the same ways it’s supposed to. So you get light and colors going all kinds of different ways. But be careful doing this, because sometimes the liquid crystal can get stuck like that and then you screen might not work anymore.
[removed]
Patient: Doctor it hurt when I do this.
Doctor: Stop doing that
But seriously it’s due to polarization in LCD screens. When certain types of plastic are under stress, cross-polarized light (which is how an LCD makes bright pixels turn dark) will create weird rainbows and other effects.
[removed]
The LCD uses liquid crystals. There’s two layers that matter – the back and the front. The back filters all the light that’s not polarized in a certain way (vibrating up and down or left and right), and the top filters all the light that’s 90* of that. So normally, no light makes it through. The liquid crystals line up in a helix when an electric field is applied, and that twists the light from up and down to left and right.
If the layer is too thin, it won’t twist enough and not enough light gets through. It’s really hard to make some kind of spacer that would work, so what displays actually do is just mix a bunch of tiny glass beads into the liquid crystal solution. This keeps the display spaced perfectly. When you press your finger on it, you’re squishing the layers together, squeezing the beads out of the way, and ensuring the liquid crystal is too thin or too thick to twist the light far enough. When you let go, everything springs back to normal.
The LC in LCD stands for Liquid Crystals. You can think of them kind of like water in a video game. They flow like a liquid, but they follow predictable patterns. The ones in your monitor are special in that they change their patterns when there is an electric current. So you can make them clear like water, or opaque like coffee.
It turns out this is pretty useful!
Let’s say you shine a light toward a piece of paper with three holes that have red, green, and blue filters. If you block all but the red one, the light will be red. If you do it with all but the blue one you’ll get blue light. You can also mix and match colors to make all sorts of different colors.
Blocking the holes manually takes a lot of time, but by using liquid crystals you can do it very quickly. By putting a layer of liquid crystals between the light and the holes with colored filters, you can let as much, or as little, light through as you need. So you can mix a little red, some blue, and a lot of green, or anything any between. And you can this very quickly.
If you take millions of these and make them very small, you basically have a monitor. Since liquid crystals behave a lot like liquids, if you put pressure on them they will flow. That will change how the light passes through it which causes distortions. Much like how ripples on a pond makes the bottom look weird.
This depends on which type of screen you have. There are LCD screens, or Liquid Crystal Display, where pushing on the screen pushes these crystals around, similar to how water moves in a plastic bag when you push on the water.
There are also OLED, which has a carbon layer, another substance, sandwiched between two electrodes, or basically a conductor. When electricity flows through this sandwich, it will emit light. Pressing on an OLED screen will not distort the image unless you are putting excessive force.
Late to this thread, but:
The screen consists of multiple layers. Top surface simply is a transparent plastic sheet, then a layer with the LCD grid, and then a white white background. (Very simplified here, but you get the idea).
It’s called Liquid (!) Crystal Display, because, well, it uses liquid crystals. When you push on the transparent top layer, you displace the liquid which is between these layers, this is when the monitor “goes weird”.
**
I personally have not found that occasional careful touching a LCD harms it but I am sure it’s not “healthy” for the display either. But I DID have screens break from pushing too hard.
The biggest issue with LCD displays (to me) is that they are not sealed, these several layers are just put together inside a frame.
Because there is a gap between the clear sheet (the surface of your monitor) and the LCD layer this creates capillary action that sucks in liquids.
Biggest mistake is to directly spray a monitor with glass cleaner, or ANY liquid for that matter. (All I am saying is…I have cats….)
The liquids runs down the screen, and then inside the monitor and gets between the layers.
So: NEVER,spray your monitor directly with any fluid. When you clean it, always spray on a paper towel first and also make sure you wipe the screen dry after cleaning.
It’s shy, ok? Be gentle with your monitor, my guy.
Latest Answers