Aperture grille

Technology used in certain color CRTs Aperture-grille-based CRT in close-up Labelled sketch showing the principle of the Trinitron picture tube Sony Trinitron aperture grille monitor Aperture-grille-based CRT in close-up, showing the letter e from a teletext page An aperture grille is one of two major technologies used to manufacture color cathode-ray tube (CRT) televisions and computer displays; the other is the shadow mask. The first patented aperture grille televisions were manufactured under the Trinitron brand name. Fine vertical wires behind the front glass of the display screen separate the different colors of phosphors into strips. These wires are positioned such that an electron beam from one of three guns at the rear of the tube is only able to strike phosphors of the appropriate color. That is, the blue electron gun will strike blue phosphors, but will find a wire blocks the path to red and green phosphors. The fine wires allow for a finer dot pitch as they can be spaced much closer together than the perforations of a shadow mask, and there need be no gap between adjacent horizontal pixels. During the display of bright images, a shadow mask warms, and expands outward in