Screen Burn-in - CRT

CRT

Further information: Comparison of CRT, LCD, Plasma, and OLED

Phosphor burn-in is particularly prevalent with monochromatic CRT screens, such as the amber or green monochrome monitors common on older computer systems and dumb terminal stations. This is partly because those screens displayed mostly non-moving images, and at one intensity: fully on. Yellow screens are more susceptible than either green or white screens because the yellow phosphor is less efficient and thus requires a higher beam current. Color screens, by contrast, use three separate phosphors (red, green, and blue) per pixel (called "sub-pixels"), mixed in varying intensities to achieve specific colors, and in typical usage patterns such as "traditional" TV viewing (non-gaming, non-converged TV usage, non-Internet browsing, broadcasts without tickers or flags, no prolonged or permanent letterboxing) are used for operations where colors and on-screen object placement approach uniformity.

Modern CRT displays are less susceptible than older CRTs because they have a layer of aluminum behind the phosphor which offers some protection. The aluminum layer was provided to reflect more light from the phosphor towards the viewer. As a bonus, the aluminum layer also prevented ion burn of the phosphor and the ion trap, common to older monochrome CRT displays, was no longer required.