Color CRT system and process with dynamic quadrupole lens structure

For use in focusing a plurality of electron beams on a screen of a color cathode ray tube, wherein said electron beams are aligned in an in-line array and are deflected across said screen by an asymmetric magnetic field which causes astigmatism of said electron beams, an electron gun comprising:

• first and third electrodes each adapted to receive a common dynamic voltage and each having for each beam a keyhole-shaped, horizontally oriented opening through which the electron beam passes;
• a second electrode between said first and third electrodes adapted to receive a fixed voltage and having for each beam a circular aperture,
• said first, second and third electrodes, when excited, establishing dynamic quadrupole fields effective to compensate the electron beams for said beam astigmatism.

For use in focusing a plurality of electron beams on a screen of a color cathode ray tube, wherein said electron beams are aligned in an in-line array and are deflected across said screen by an asymmetric magnetic field which causes astigmatism of said electron beams, an electron gun comprising:

• first and third electrodes each adapted to receive a common dynamic voltage and having a horizontally elongated slot through which the electron beams pass;
• a second electrode between said first and third electrodes adapted to receive a fixed voltage and having for each beam a circular aperture,
• said first, second and third electrodes, when excited, establishing dynamic quadrupole fields to the electron beams effective to compensate for said beam astigmatism.