Patent ID: 6411027
Filing Date: 2002-06-25
Classification: H01J

Abstract:
A color display device comprisingan in-line electron gun (5) for generating three electron beams (6,7,8) being located substantially within a plane extending in an X-direction of a rectangular X-Y coordinate system, deflecting means (51) for deflecting the electron, and convergence means (14â€²) for dynamically influencing the convergence of the electron beams, the convergence means (14â€²) comprising a ring-shaped element (21â€²) having four coils (22â€²), said coils (22â€²) comprising electrically conductive wires, which have been toroidally wound in a winding direction and according to a winding density distribution N (&phgr;) given by N (&phgr;)=N0 cos (2&phgr;); where &phgr; is an angle enclosed by the X-direction and a line between an element of the coil and the center, which ranges between 0Â° and 360Â°, N0 is the winding density at &phgr; equal to 0Â°, and the sign of N (&phgr;) denotes the winding direction.