A masking technology invented by Sony to be used in monitors, that allows for a brighter image then a shadow mask. It is made of fine metal wires instead of a perferated metal plate to block stray electrons. A downside of the technology is that it usually has 2 fine horizontal lines in the middle of the screen created by the dampening wires.
In some CRTs, the aperture grille is a series of wires stretched vertically down the inside of the monitor to mask the beams from the electron guns at the back of the tube. In other types of monitors, this function falls to a perforated metal plate called a shadow mask. Some users prefer the image quality of Sony Trinitron monitors, which use an aperture grille; others notice the faint horizontal shadows cast by the grille's tensioning wires and prefer other shadow-mask designs.
a high-tension grill that permits more electrons to pass through to the screen in comparison to conventional shadow mask grilles used by other manufacturers