Screensaver

A screensaver (or screen saver) is software that controls a monitor of the host computer with the intent of preventing screen burn-in for a screen susceptible to it. Generally, a screensaver starts controlling a monitor when the computer has been idle for a designated period of time and fills the screen either with black (all pixels off) or with changing graphics that tend to prevent each pixel from being on for a long time. Although monitors were commonly constructed with screen technology that was susceptible to burn-in (CRT and plasma), most modern monitors use LCD, which is not. Another modern technology, OLED, is susceptible. In addition to the feature described by its name (saving a screen from burn-in), a screensaver may provide other features. It may provide physical security by requiring a password to exit the screen control mode (acting as a lock screen). Some use otherwise-idle computer resources to do useful work, such as processing for volunteer computing projects. Many modern devices such as televisions and other digital entertainment devices include a screensaver.