Color cathode ray tube apparatus

A color cathode ray tube apparatus comprising:

• an enclosure including a panel section having a phosphor screen and a shadow mask, a funnel section mounted externally with a deflecting yoke and a neck section;
• an electron gun assembly provided in the neck section of the enclosure, having
• three cathodes for emitting electron beams which are parallel to each other in a first plane, and
• a group of electrodes located in front of the cathodes with a predetermined interval between the adjacent electrodes, and having three electron beam paths for passing the electron beams, each electrode having three through-holes which compose the electron beam paths, the group of electrodes including
• rear electrodes for forming an auxiliary lens for preliminarily focusing the electron beams, one of the rear electrodes having a pair of electrode members applied with a relatively lower voltage, each member having cylindrical projections defining the through-holes, the cylindrical projections on one of the electrode members facing their counterparts on the other electrode member with a predetermined interval therebetween and each having an oblique surface at its end, each oblique surface having a predetermined angle with respect to a second plane perpendicular to the axis of the electron beam path but standing at right angles with the first plane, whereby the oblique surfaces of the projections have substantially the same inclination with respect to the electron beam paths, and
• a front electrode located in front of the rear electrodes to form a main lens, in cooperation with one of the rear electrodes that is adjacent to the front electrode for further focusing the electron beams preliminarily focused by the rear electrodes and for converging the electron beams;
• and
• a device connected to the electrodes for supplying an operating voltage thereto, having means for supplying a modulating voltage for modulating a scanning velocity of the electron beams to the pair of electrode members, when luminance values of a video signal arrive at a predetermined level.