Color display device with first and second dynamic focusing voltages

An electron gun for use in an electron beam color display tube having a deflection unit, comprising:

• an electron beam triode generating means,
• first and second electrodes aligned along the longitudinal axis of the electron gun,
• first and second focus electrodes adjacent one another and aligned along the longitudinal axis of the electron gun,
• a final electrode aligned along the longitudinal axis of the electron gun with the first and second focus electrodes, wherein
• the first and second focus electrodes form a quadrupole lens system and the second focus electrode and the final electrode form a main lens, and
• a first dynamic voltage is applied to the first focus electrode and a second dynamic voltage is applied to the second focus electrode.

A method of displaying video information on the screen of a color display tube having an electron gun and a deflection unit, comprising:

• generating an electron beam by means of said electron gun,
• accelerating the electron beam towards the screen of the color display tube,
• deflecting the electron beam in a horizontal and a vertical direction,
• applying a first dynamic focus voltage to a first focus electrode of the electron gun, and applying a second different dynamic focus voltage to a second focus electrode of the electron gun.