Multi-beam group electron gun with common lens for color crt

Abstract

An inline electron gun for a color cathode ray tube (CRT) directs electron beams through an Einzel lens common to all of the beams for focusing the beams on a display screen across which the beams are scanned in horizontal scan lines in a raster-like manner. The electron gun includes a beam forming region (BFR) for forming the beams in a matrix array including a plurality of vertically spaced, horizontally aligned apertures, where each horizontally aligned group of apertures passes the primary color electron beams for one scan line on the display screen and vertically aligned apertures are grouped to pass common color electron beams which are horizontally deflected in synchronism over adjacent, vertically spaced scan lines on the display screen. All of the electron beams converge and cross over the electron gun's axis at the center of the Einzel lens, with the diverging beams then directed through a convergence arrangement which converges each group of the horizontally aligned beams to a common spot on a given scan line permitting video display information to be presented simultaneously on more than one scan line. The beam convergence arrangement equalizes the vertical and horizontal convergence effects on each of the beams in the matrix array of beams to deflect the outer beams inwardly while deflecting the upper and lower beams respectively downwardly and upwardly so that each group of horizontally aligned beams converge on the center beam of that group at the display screen.