Patent ID: 6259195
Filing Date: 2001-07-10
Classification: H01J

Abstract:
A cathode ray tube comprising an electron gun having a beam shaping portion having at least one electron source for generating an electron beam, a prefocusing electrode system including first and second prefocusing electrodes across which a prefocusing voltage is supplied during operation so as to form an electron-optical prefocusing lens, the electron gun further comprising a main lens electrode system including first and second main lens electrodes provided with means for supplying, at least during operation, a main focusing voltage between said electrodes so as to form an electron-optical main focusing lens, each of said electrodes being provided with at least one aperture for passing the electron beam and with securing means with which the electrode is secured to at insulating supporting body, characterized in that the second prefocusing electrode and the first main lens electrode are mutually electrically connected, one of the first and second prefocusing electrodes protruding toward the other in such a way that the distance between said electrodes at the location of the apertures therein is smaller than at the location of the respective securing means thereof, in that the electrodes at the location of the apertures provided therein are spaced apart substantially at a distance which is limited by electrostatic breakdown and in that the distance between the first and second prefocusing electrodes at the location of the apertures therein is approximately a factor of three smaller than at the location of the respective securing means thereof.