shadow mask



  • In a picture tube with a three-color gun, a grill with round holes that is placed behind the screen to make sure that each color beam strikes the correct phosphor dot on the screen. It insures, for instance, that the electron beam intended for the red phosphor dots only hits those. Also called aperture mask, or mask (3).

Media Studies

  • noun a metal sheet with very small holes in it that is situated close to the back of the phosphor screen of some types of colour television tubes.