Patent ID: 7045976
Filing Date: 2006-05-16
Classification: H01J

Abstract:
1. An electron gun for cathode ray tube comprising aligned in series along an axis: an electron-emitting cathode, a first electrode and a second electrode effecting the formation of an electron beam and being focused to a so-called crossover point, an electron lens for prefocusing the electron beam comprising three successive electrodes: G a first quadripolar device electrically controlled in a dynamic manner in synchronism with a screen scan so as to correct beam focusing defects at a screen edge, a main electron lens making it possible to focus the electron beam onto a screen, the gun also comprising a second quadripolar device comprising a first electrode, a second electrode and a third electrode, the second quadripolar device being situated between the prefocusing electron lens and the first quadripolar device, characterized in that: the second electrode of the second quadripolar device exhibits apertures of substantially rectangular shape whose large sides are oriented in a first direction, the first and third electrodes of the second quadripolar device exhibit facing the second electrode apertures of substantially rectangular shape whose large sides are oriented in a second direction orthogonal to the first direction, the first electrode and the third electrode being placed at a fixed polarization potential, the second electrode being at a polarization potential varying in synchronism with the screen scan.