Patent ID: 6157122
Filing Date: 2000-12-05
Classification: H01J

Abstract:
A color cathode ray tube includinga vacuum envelope comprising a panel portion, a neck portion, and a funnel portion connecting said panel portion and said neck portion;a phosphor screen on an inner surface of said panel portion;a shadow mask suspended closely spaced from said phosphor screen in said panel portion;an electron gun comprising a plurality of electrodes for generating and focusing three in-line electron beams and housed within said neck portion;a deflection device mounted around a transition area between said funnel portion and said neck portion for deflecting said three in-line electron beams in horizontal and vertical directions; anda convergence correction device comprising a plurality of magnetic pieces positioned on opposite sides of each of said three in-line electron beams in an in-line direction of said three in-line electron beams in magnetic deflection fields generated by said deflection device;said plurality of magnetic pieces including a first pair of magnetic pieces positioned on a neck wall side of each of side electron beams of said three in-line electron beams in said in-line direction and a second pair of magnetic pieces positioned on opposite sides of a center electron beam of said three in-line electron beams in said in-line direction; andsaid first pair of magnetic pieces each having a first pair of protruding portions extending toward an adjacent one of said second pair of magnetic pieces, said first pair of protruding portions of said first pair of magnetic pieces being arranged on opposite sides of a corresponding one of said side electron beams of said three in-line electron beams in a direction perpendicular to said in-line direction;said second pair of magnetic pieces each having two second pairs of protruding portions, one of said second pairs of protruding portions extending toward an adjacent one of said first pair of magnetic pieces and the other of said second pairs of protruding portions extending toward an adjacent one of said second pair of magnetic pieces each of said second pairs of protruding portions of said second pair of magnetic pieces being arranged on opposite sides of a corresponding one of said three in-line electron beams in a direction perpendicular to said in-line direction;said first pair of magnetic pieces having a portion of an axial length greater than an axial length of said second pair of magnetic pieces; andsaid axial lengths being measured in a plane containing said in-line direction and a longitudinal axis of said color cathode ray tube.