Abstract: A cathode ray tube comprises an electron gun for generating electron beams. External magnetic fields influence the electron beams and reduce the picture quality. An electrode of the gun includes a part of a soft-magnetic material, which extends transversely to the electron beams, and two parts, situated to the left and to the right of the electron beams, which extend along the electron beams. Together these parts form a magnetic circuit. Preferably, these parts are strongly magnetically coupled, for example, because they are interconnected or very closely spaced. Interaction of the magnetic circuit formed by the three parts with an external magnetic field causes a Lorentz force on the electron beams. The resultant deviations in the paths of the electron beams largely compensate for the deviations in the paths of the electron beams caused by the effect of the external magnetic field between the electron gun and the display screen.

Abstract: The centering cup of an in-line electron gun of a color cathode ray tube is provided with four slits, positioned substantially mirror-symmetrical with respect to the in-line plane and with respect to a plane perpendicular to the in-line plane through the central aperture, a line drawn through two slits and the central opening making an angle with the in-line plane ranging between 51 and 63 degrees. The slits reduce the occurrence of eddy currents, without introducing convergence errors.