dead pixel

A pixel on an LCD screen in which a defective transistor is permanently turned off. It shows up as a dark spot on the screen. Contrast with "lit pixel," in which the transistor is permanently turned on and shows up as a red, green or blue dot. Contiguous lit pixels show up as the color produced by the combination of pixels.

Does It Matter?
It depends. On an LCD TV, which is displaying motion and is situated several feet from the viewer, dead or lit pixels may not matter. On a computer monitor only two feet away, they may be very annoying, especially if located in the center of the screen. Equipment manufacturers have different policies regarding defective pixels. They typically state that if a certain number of bad pixels exist, the unit may be returned.