How an LCD pixel controls light
An LCD screen does not make its own light. A backlight shines through layers of filters and liquid crystals, while tiny electrical controls adjust how much light reaches each red, green, and blue subpixel. Together, those subpixels produce the colors you see.
The liquid crystals act like adjustable shutters. Changing the voltage changes their alignment, which changes how light passes through the pixel. If a control element or its connection fails in a way that leaves a subpixel transmitting light, it may stay visibly bright even when the screen is trying to make that area dark. The problem is not necessarily a crystal physically jammed in place; “stuck” describes the persistent display behavior.
Why the spot changes with the image
A stuck-bright subpixel stands out most against a dark background because its light contrasts with the surrounding screen. On a bright or similarly colored image, it may be difficult to notice. A pixel is also made of separate color subpixels, so a fault affecting just one can look like a tiny colored dot rather than a white one.
That differs from a pixel that produces no light, though people and manufacturers do not always use “dead” and “stuck” in exactly the same way. The distinction matters because a bright spot can still be responding incorrectly to the screen’s light-control system—not simply failing to illuminate. A single glowing point can therefore reveal a failure in the tiny electrical mechanism that regulates light, even while the rest of the display works normally.
