Color selection means having a charged insulator portion for a cathode-ray tube

摘要

A cathode-ray tube includes a display screen having an array of phosphor stripes of three different emission colors arranged in cyclic order in adjacent triads. The tube further includes an electron gun for producing three convergent inline electron beams directed toward the display screen. A color selection structure is positioned between the display screen and the electron gun. The color selection structure includes a metal masking plate having therein an array of apertures arranged in columns that are substantially parallel to the phosphor stripes. The color selection structure further includes beam-influencing strips of insulation disposed on the masking plate which, in combination with the masking plate, define an array of windows for transmitting therethrough portions of the electron beams. A high voltage contact is provided for applying a potential to the metal masking plate and to the display screen. The strips of insulation are parallel to the phosphor stripes of the display screen. The strips of insulation are charged to a focusing potential by secondary electrons incident thereon and emanating from the display screen as a result of impingement thereon of the electron beams from the electron gun.