High Quality Content by WIKIPEDIA articles! A monitor filter is an accessory to the computer display to filter out the light reflected from the smooth glass surface of a CRT or flat screen display as well as the radiation emitted from CRT and LCD displays. Many also include a ground to dissipate static buildup. A secondary use for monitor filters is privacy as they decrease the viewing angle of a monitor, preventing it from being viewed from the side; in this case, they are also called privacy screens.