COLOR PICTURE TUBE Russian patent published in 1994 - IPC

FIELD: TV. SUBSTANCE: color picture tube has observation screen and electronic gun to generate and direct three coplanar electron beams - two side and one central-to screen. Gun includes electrodes with three coplanar apertures in each forming three focusing lenses. First lens is put in beam-forming region of gun, second lens includes at least one electrode to form asymmetric beams for third lens. Third lens is common basic focusing lens of all three beams. It has three electrodes, in one of them, most remote from cathodes, there is made recession in the form of dumb-bell embracing apertures. Dimensions of this recession are chosen from condition of provision of third lens with main share of correction of focusing of each separate electron beam. For provision of remaining share of correction of focusing electrode used for formation of beams of asymmetric shape is manufactured in the form of plate with different thickness in areas of central and side apertures. EFFECT: enhanced efficiency of color picture tube. 3 cl, 14 dwg