A weird black dot is probably one of the most disheartening things you can run into when buying a new screen. That, dear readers, is a dead pixel. Here’s why they happen and what you can do about it.
What Causes a Dead Pixel
Before jumping headlong into fixing dead pixels, it’s important first to understand how pixels work in a monitor. The primary technology that runs monitors is Liquid Crystal Display or LCD for short.
How it works is that two polarizing filters sandwich a layer of liquid crystal, a name for a type of liquid that can also exhibit properties of crystals. Behind that sandwich is a backlight that provides the light source that you see from your monitor. As that light passes through the sandwich, each layer is altered using electrons to produce either light, no light, or some gradient between the two. At an individual level, these are called electrodes and are the building block of LCD monitors.
If you want to get color out of your LCD, you add another three layers of filters—usually red, green, and blue. Again, by adjusting the number of electrons that go into each color of the filter, you can increase or decrease the hue and intensity, thereby giving you a specific RGB value that your eyes interpret as color. Therefore, each pixel is made of three different electrodes, one for each color.
When you have an issue with a pixel, the underlying cause is that one or more electrodes for that pixel are malfunctioning somehow.
Types of Pixel Defects: Stuck, Hot, and Dead
Alright, so you know how pixels work and you have a dead one to deal with—-but, do you really have a dead pixel? There are various pixel issues you might encounter. If you’re lucky, you’re not dealing with a dead pixel.
For example, one of the most common defects is a “stuck pixel.” Thankfully there are a few things you can try to fix a stuck pixel.
Another defect is a “hot pixel,” which is a pixel that is always bright. That’s because the electrodes behind it allow all light to go through, regardless of what is on the screen. The opposite is called a dark dot defect, where no light is going through, although this defect is slightly rarer.
Finally, we have the dead pixel, and this one is the real killer because that means the electrodes behind the pixel have failed completely.
Can You Fix a Dead Pixel?
Unfortunately, as a consumer, there’s no direct way for you to fix a dead pixel since it’s a manufacturing defect or transportation issue 99% of the time. At that point, the only option you have is to look at the warranty that comes with your screen and see if dead pixels are covered or not.
Ultimately, this can vary depending on the manufacturer and the class of screen you have. For example, Class I monitors do not allow for any dead pixels, so the manufacturer will replace them with one in perfect working order.
On the other hand, Class III monitors allow for up to 15 dead pixels and three clusters of stuck pixels. If your dead pixel problem isn’t big enough, it won’t be covered under your manufacturer’s warranty.
Interestingly enough, sometimes manufacturers will take these defective screens and sell them for a massively reduced price. It’s a great way to recycle the products for uses where dead or stuck pixels won’t cause that big of an issue, such as in industrial processes or server rooms where graphical quality is not essential.