Cathode ray tube

A cathode ray tube, comprising:

• an electron gun including an electron beam forming section for forming and emitting at least one electron beam and a main lens portion for accelerating and focusing the electron beam, said main electron lens portion including at least four electrodes in the order of first, second, third and fourth grids, the first and second grids being closely arranged and the third and fourth grids being closely arranged, and including a resistor connected to each of the second and third grids, and these first to fourth grids being constructed and arranged such that a second electrostatic capacitance between the second and third grids is smaller than any of a first electrostatic capacitance between the first and second grids and a third electrostatic capacitance between the third and fourth grids;
• a deflection yoke generating a deflecting magnetic field for deflecting the electron beam emitted from the electron gun in horizontal and vertical directions to have the screen scanned by the electron beam;
• means for generating an intermediate first voltage and an anode voltage;
• and
• means for generating a dynamic focusing voltage which is varied depending on the deflection of the electron beam;
• wherein
• the intermediate first voltage and the dynamic focusing voltage are applied to the first grid, the anode voltage is applied to the fourth grid, the anode voltage is divided by the resistor to generate a second voltage and a third voltage that are higher than the first voltage and lower than the anode voltage, and the second and third voltages are applied to the second and third grids, respectively, said second and third voltages being substantially same potential;
• and
• a first lens region is formed between the first and second grids, a third lens region is formed between the third and fourth grids, a second lens region is formed between the second and third grids, and an asymmetric lens is formed in the second lens region.