Patent ID: 6646381
Filing Date: 2003-11-11
Classification: H01J

Abstract:
A cathode-ray tube apparatus including:an electron gun assembly having an electron beam generating section which generates three electron beams consisting of a center beam and a pair of side beams positioned on both sides of the center beam, and a main lens section which focus the electron beams generated by the electron beam generating section onto a phosphor screen; and a deflection yoke which deflects the electron beams emitted from the electron gun assembly in a horizontal direction and a vertical direction, wherein the main lens section comprises a focus electrode, to which a focus voltage of a first level is applied, an anode, to which an anode voltage of a second level higher than the first level is applied, and at least one intermediate electrode which is disposed between the focus electrode and the anode and to which a voltage of a substantially intermediate level between the first level and the second level is applied, the focus electrode has, in a first end face thereof opposed to the intermediate electrode, three electron beam passage holes for passing the three electron beams, the electron gun assembly includes an asymmetric lens section which has such asymmetry that lens functions of the asymmetric lens section acting on the electron beams are different between the horizontal direction and the vertical direction, and which has a lens power varying in synchronism with the deflection of the electron beams, and the asymmetric lens section is created at a position away by a distance or less, which corresponds to a diameter of the electron beam passage hole formed in said first end face, from the first end face of the focus electrode toward the electron beam generating section, the asymmetric lens section having an asymmetry of a lens function acting on the center beam, which differs from an asymmetry of a lens function acting on the side beams.