Electron gun for color picture tube

A color picture tube, comprising:

• a glass envelope provided with a fluorescent screen at an end face thereof;
• electron beam generating means disposed in said glass envelope for generating three electron beams, said beams being substantially parallel to one another and directed to said fluorescent screen and being arranged so as to define one plane;
• and
• a main lens for focusing said three electron beams on said fluorescent screen, said main lens including electrodes spaced apart from each other, said electrodes having:
• (a) at least two envelopes surrounding said three electron beams and having opposing ends which confront each other;
• and
• (b) electrode plates each disposed on a different one of said envelopes proximate to an opposing end so as to form confronting end faces in said envelopes, each of said electrode plates being shaped such that a single aperture is provided in said electrode plate so that said single aperture surrounds only the center path for the center electron beam among said three electron beams, said electrode plates having end portions configured so that the path for each outer electron beam is partly surrounded by a corresponding one of said end portions, at least one of said electrode plates being provided in one of said envelopes such that said electrode plate is recessed from the end of said one envelope confronting the other envelope.