Color display system having an electron gun with dual electrode modulation

In a color display system including a cathode-ray tube having an envelope with an inline electron gun therein for generating and directing three inline electron beams along initially coplanar paths towards a screen on an interior portion of said envelope, said gun including a plurality of spaced electrodes which provide a first lens, a second lens and a third lens for focusing said electron beams, said first lens including a beam-forming region for providing substantially symmetrical beams to said second lens and, said second lens including three electrodes, one of which being a first modulation electrode disposed between the two other electrodes of said second lens, said system including a self-converging yoke that produces an astigmatic field, the improvement comprising

• said second lens including means for applying a first vertical rate modulation voltage signal to a said first modulation electrode thereof, and asymmetric beam-focusing means for providing asymmetrically-shaped beams to said third lens, and
• said third lens including means for applying a first horizontal rate modulation voltage signal to a second modulation electrode thereof, said first vertical and horizontal rate modulation signals being related to deflection of the electron beams.

In a color cathode-ray tube including an envelope having therein an inline electron gun for generating and directing three inline electron beams along initially coplanar electron beam paths towards a screen on an interior portion of said envelope, said gun including a plurality of spaced electrodes which provide a first lens, a second lens and a third lens for focusing said electron beams, said first lens including a beam-forming region for providing substantially symmetrical beams to said second lens, said second lens including rotationally asymmetrical beam-focusing means for providing asymmetrically-shaped beams to said third lens, and said third lens being a low aberration main focusing lens, wherein the improvement comprises

• said rotationally asymmetrical beam-focusing means of said second lens including a first modulation electrode with three rotationally asymmetrical inline opening therethrough, each of said openings being elongated in the direction of the inline openings, each of said openings including a substantially circular center portion and two oppositely disposed arcuate portions intersecting the circumference of said circular center portion.

In a color display system including a cathode-ray tube having an envelope with an inline electron gun therein for generating and directing three inline electron beams along initially coplanar paths towards a screen on an interior surface of said envelope, said gun including a plurality of spaced electrodes which provide a first lens, a second lens and a third lens for focusing said electron beams, said first lens including a beam-forming region for providing substantially symmetrical beams to said second lens, said second lens including three electrodes, one of which being a first modulation electrode, and said system including a magnetic deflection yoke that produces an astigmatic magnetic deflection field, the improvement comprising

• means for applying at least a first dynamic voltage signal to said first modulation electrode of said second lens electrodes, and
• means for simultaneous applying a second dynamic voltage signal to a second modulation electrode of said third lens, said second modulation electrode being electrically separate from said first modulation electrode, said first and second signals being related to deflection of the electron beams.

In a color display system including a cathode-ray tube having an envelope with an inline electron gun therein for generating and directing three inline electron beams along initially coplanar paths towards a screen on an interior portion of said envelope, said gun including a plurality of spaced electrodes which provide a first lens, a second lens and a third lens for focusing said electron beams, said first lens including a beam-forming region for providing substantially symmetrical beams to said second lens, said second lens including three electrodes, one of which being a first modulation electrode disposed between the other two electrodes of said second lens, said system including a self-converging yoke that produces an astigmatic magnetic field, the improvement comprising

• said second lens including means for applying a first vertical rate modulation voltage signal to a first modulation electrode thereof, and asymmetric beam-focusing means for providing asymmetrically-shaped beams to said third lens, and
• said third lens including means for applying a first horizontal rate modulation voltage signal to a second modulation electrode thereof, said second modulation electrode being electrically separate from said first modulation electrode, said first vertical and horizontal rate modulation signals being related to deflection of the electron beams.