Patent ID: 6608435
Filing Date: 2003-08-19
Classification: H01J

Abstract:
A cathode ray tube apparatus having a screen, comprising:an electron gun assembly provided with electron beam forming means for generating and emitting at least one electron beam, said electron beam forming means including a cathode and a plurality of electrodes disposed along an electron beam traveling direction, and a main focus lens for focusing the electron beam from the cathode on the screen; and a deflection yoke for generating a deflection magnetic field deflecting the electron beam in horizontal and vertical directions to scan the screen with the deflected electron beam, wherein the main focus lens of the electron gun assembly is formed by focus electrodes and an anode electrode, focus voltages having intermediate voltage levels being applied to the focus electrodes from an outside of the electron gun assembly and an anode voltage having a high voltage level being applied to the anode electrode, the focus electrodes including at least one focus electrode to which a constant focus voltage is applied from the outside of a tube, and at least one dynamic focus electrode to which a dynamic focus voltage varied in synchronism with the deflection magnetic field generated from the deflection yoke is applied, and a resistor being connected to at least two electrodes which constitutes the electron beam forming means, a fixed voltage being applied from an outside of the tube to the one of the electrodes connected to the resistor, the another one of the electrodes connected to the resistor is so arranged to face the dynamic focus electrode to which the dynamic focus voltage varied in synchronism with the deflection magnetic field generated from the deflection yoke is applied to form the main lens, and axially asymmetrical lens forming means for forming an axially asymmetrical lens being formed between the at least two electrodes connected to the resistor.