Patent ID: 7122977

Claim:
A cathode-ray tube apparatus comprising: an electron gun assembly including an electron beam generating section that generates an electron beam, a prefocus lens section that prefocuses the electron beam generated from the electron beam generating section, and a main lens section that accelerates and focuses the prefocused electron beam onto a phosphor screen; a deflection yoke that generates deflection magnetic fields for deflecting the electron beam emitted from the electron gun assembly in a horizontal direction and a vertical direction on the phosphor screen; and a sub-lens section between the prefocus lens section and the main lens section, wherein the main lens section includes a focus electrode, to which a focus voltage is applied, an anode electrode, to which an anode voltage with a level higher than the focus voltage is applied, and at least one intermediate electrode, to which a voltage with a level between the focus voltage and the anode voltage is applied, said at least one intermediate electrode being disposed between the focus electrode and the anode electrode, each of the focus electrode, the anode electrode and the intermediate electrode includes, at opposed faces thereof, at least one cylindrical body extending in a direction of travel of the electron beam, the prefocus lens section includes a screen electrode, to which a voltage with a level lower than the focus voltage is applied, and at least one additional electrode, to which a voltage with a level between the focus voltage and the anode voltage, is applied, and the sub-lens section is configured to decelerate and further prefocus the electron beam that is prefocused by the prefocus lens section.