In-line electron gun for a colored cathode ray

Abstract

A color cathode ray tube apparatus is provided with an electron gun assembly which emits three electron beams and focuses and converges the electron beam onto a phosphor screen. In the gun assembly, the electron beams generated from cathodes are accelerated and controlled by first and second grids and pass through third, fourth and fifth grids. The third and fourth grids have single rectangular apertures common to the three electron beams, respectively, which are faced to each other and have different heights and widths. Each of the fourth and fifth grids have individual apertures which allow the corresponding electron beams to pass therethrough, respectively. The third and fifth grids is maintained at fixed potentials and a potential of the fourth grid is adjusted. Thus, individual focusing and convergence electron lenses are formed between the fourth and fifth grids. A single and common asymmetrical electron lens is formed between the third and fourth grids, when a potential difference between the third and fourth grids is produced. A misconvergence of three electron beams produced due to the adjustment of the individual electron lenses is corrected by the common asymmetrical electron lens in such a manner that the side electron beams are deflected in accordance with the potential difference.