GB1454679A - Apparatus for the deflection and convergence correction of electron beams in colour television tubes - Google Patents

Abstract

1454679 Electron beam magnetic deflecting apparatus VIDEON SA 9 July 1974 [11 July 1973] 30290/74 Heading H1D Apparatus for electron beam deflection and convergence correction in a colour c.r.t., the beam systems of which are coplanar, comprises two pairs of saddle/deflection coils 1, 2 for deflection in two orthogonal directions mounted in a frame (8) (Fig. 2, not shown) securable to the neck of the tube, four toroidal correction coils 4, 5, 6, 7 wound on a ferrite core 3 to produce a four-pole field, two of the coils acting along a vertical axis and two along a horizontal axis, the ferrite core being on a movable part of the frame, the toroidal coils, the movable part of the frame, and the core forming a unit rotatable within predetermined angular limits (e.g. a few degrees to the right or left) while the deflection winding are retained in position, the arrangement allows optimum alignment of the coils with the beams. Core 3 may be split, and coils 4 to 7 are series connected, or wound so as to produce force lines superposed on the deflection field. Figs. 2 and 3 (not shown) indicate force lines for horizontal and vertical beam arrangements. Parabolic currents are supplied to coils 4 to 7. Clip (9) secures the deflection unit to the tube neck, and frame (8) has two raised portions with tapped bores (10). Coils 4 to 7 are on a movable part of the frame with flange (11) having arcuate slots (12) (Fig. 5, not shown) for wing bolts (13).