What Is a Dead Pixel and Why Do They Occur?
Display devices like computer monitors, televisions, smartphone screens and human machine interface (HMI) screens are comprised of many individual pixels. Depending on the type of display device, it may contain hundreds of thousands or even millions of pixels. Normally, the pixels will perform their intended function by changing color in response to the image being projected. There are times, however, when a pixel can die.
Overview of Dead Pixels
A dead pixel is a phenomenon in which a pixel on a display device fails to change color. As previously mentioned, pixels are designed to change color. When a display device produces an image, its pixels feature the appropriate colors of the image. The term "dead pixel" refers to a pixel that fails to change color.
Dead pixels are distinguished from other pixels by remaining black at all times. Regardless of the image being displayed, a dead pixel will remain black. Therefore, they are relatively easy to spot by turning the display device to a white or otherwise bright image. If the display device projects an all or mostly white image, dead pixels will stick out.
What causes dead pixels exactly? Most instances of dead pixels are the result of a failed power connection. Pixels require power to change color. If the power connection to a pixel is cut off, it will become a black and dead pixel.
Dead vs Stuck Pixel: What's the Difference?
Another phenomenon that can occur with display devices is a stuck pixel. Like dead pixels, stuck pixels don't change color. That doesn't necessarily mean they are the same as dead pixels, though. Stuck pixels are different in the sense that they are typically red, green or blue. In comparison, dead pixels are black.

