Colour picture tubes containing an in-line type electron gun assemblies

Claim 1

In an in-line type colour picture tube of the type comprising three electron guns arranged on a straight line, and means for adjusting on substantially the same plane the dynamic convergence and the static convergence provided for concentrating three electron beams emanated from said three electron guns at a point on the fluorescent screen of said colour picture tube, the improvement which comprises a pole piece assembly disposed in said plane of convergence adjustment, said pole piece assembly including a first pair of spaced pole piece segments substantially symmetrically disposed with respect to a plane perpendicular to said straight line, which plane passes through the axis of a central electron gun, one of said first paired pole piece segments being disposed between the axes of the central electron gun and an outer electron gun, the other being disposed between the axes of the central electron gun and the other outer electron gun, individual segments of said first paired pole piece segments being disposed also symmetrically with respect to another plane passing through the axes of the three electron guns and opposed to each other by a smaller distance at said straight line than at the extremities remote from said straight line, and a second pair of pole piece segments being disposed symmetricalLy with respect to said plane passing through the axes of three electron guns, individual segments of said second paired pole piece segments being disposed also substantially symmetrically with respect to said plane perpendicular to said straight line and passing through the axis of the central electron gun, and having a web projecting toward said central electron gun substantially on the last mentioned plane.