Color cathode-ray tube apparatus

A color cathode-ray tube apparatus comprising:

• an electron gun structure having a plurality of electrodes for constituting a plurality of electron lenses including a main lens for focusing three electron beams on a phosphor screen, the three electron beams being arranged in line in a horizontal direction;
• and
• a deflection yoke for producing deflection magnetic fields for deflecting the three electron beams emitted from the electron gun structure in the horizontal direction and a vertical direction,
• wherein the main lens comprises a focus electrode, an anode electrode, at least one additional electrode disposed between the focus electrode and the anode electrode, and voltage application means for applying to the additional electrode a voltage which is higher than a voltage applied to the focus electrode and lower than a voltage applied to the anode electrode, and
• an electron beam passage hole formed in the additional electrode has a waist portion substantially acting on formation of the electron lenses, the waist portion minimizing a horizontal dimension of a region where the electron beam passes, and
• a value S, which is given by
• S=[(application voltage to the additional electrode)−(application voltage to the focus electrode)]/[(application voltage to the anode electrode)−(application voltage to the focus electrode)],
• varies in synchronism with deflection of the three electron beams by the deflection yoke.

A color cathode-ray tube apparatus comprising:

• an electron gun structure having a plurality of electrodes for constituting a plurality of electron lenses including a main lens for focusing an electron beam on a phosphor screen;
• and
• a deflection yoke for producing deflection magnetic fields for deflecting the electron beam emitted from the electron gun structure in a horizontal direction and a vertical direction,
• wherein an electron beam passage hole formed in at least one of the electrodes constituting the main lens has a waist portion substantially acting on formation of the electron lenses, the waist portion minimizing a vertical dimension of a region where the electron beam passes.

A color cathode-ray tube apparatus comprising:

• an electron gun structure having a plurality of electrodes for constituting a plurality of electron lenses including a main lens for focusing three electron beams on a phosphor screen, the three electron beams being arranged in line in a horizontal direction;
• and
• a deflection yoke for producing deflection magnetic fields for deflecting the three electron beams emitted from the electron gun structure in the horizontal direction and a vertical direction,
• wherein the main lens comprises a focus electrode, an anode electrode, at least one additional electrode disposed between the focus electrode and the anode electrode, and voltage application means for applying to the additional electrode a voltage which is higher than a voltage applied to the focus electrode and lower than a voltage applied to the anode electrode, and
• an electron beam passage hole formed in the additional electrode has a waist portion substantially acting on formation of the electron lenses, the waist portion minimizing a vertical dimension of a region where the electron beam passes, and
• a value S, which is given by
• S=[(application voltage to the additional electrode)−(application voltage to the focus electrode)]/[(application voltage to the anode electrode)−(application voltage to the focus electrode)],
• varies in synchronism with deflection of the three electron beams by the deflection yoke.