When the same image is displayed on a CRT screen for long periods, the properties of the exposed areas of the phosphor coating on the inside of the screen gradually and permanently change, eventually leading to a darkened shadow or 'ghost' image on the screen, called a screen burn-in. Purpose Screen protection īefore the advent of LCD screens, most computer screens were based on cathode ray tubes (CRTs). Īs well as computers, modern television operating systems, media players, and other digital entertainment systems may include optional screensavers. Some screensaver programs also use otherwise-idle computer resources to do useful work, such as processing for volunteer computing projects. Screensavers are often set up to offer a basic layer of security by requiring a password to re-access the device. Though most modern monitors are not susceptible to this issue (with the notable exception of OLED technology, which has individual pixels vulnerable to burnout), screensaver programs are still used for other purposes.

The original purpose of screensavers was to prevent phosphor burn-in on CRT or plasma computer monitors (hence the name).

For CAD scripts, see CadSoft EAGLE.Ī screensaver (or screen saver) is a computer program that blanks the display screen or fills it with moving images or patterns when the computer has been idle for a designated time.

Moving screensavers