In-line type electron gun and color cathode ray tube apparatus using the same

Abstract

An in-line type electron gun using a field superimposing type main lens system is provided that can attain good focusing properties by decreasing the size of the electron beam spot on the entire surface of the phosphor screen without being formed to be mechanically large. A field superimposing type main lens is formed by disposing two tubular electrodes opposite to each other and disposing a plate-like field correction electrode on each of the tubular electrodes on the sides not opposite to each other. On each of the opposite sides of the two tubular electrodes, an opening is formed by an edge portion and a folded portion. The shape of the opening may be an elongated flat-sided oval shaped aperture (laterally elongated aperture) that is formed by straight lines and semicircles and has a major diameter in the horizontal direction and a minor diameter in the vertical direction. The in-line type electron gun is configured such that a relationship B<A is satisfied, where A represents a minor diameter of the opening in the tubular electrode to which a relatively low voltage is applied, and B represents a minor diameter of the opening in the tubular electrode to which a relatively high voltage is applied.