GB482513A - Improvements in or relating to deflecting means for cathode-ray tubes or the like - Google Patents

Abstract

482,513. Discharge apparatus. FERNSEH AKT.-GES. Sept. 30, 1936, No. 26501. Convention date, Sept. 30, 1935. [Class 39 (i)] The longitudinal conductors of the deflecting coil of a cathode-ray tube or like electrondischarge device lie between the surfaces of two concentric cylinders or cones which are coaxial with the tube, and the current in conductors lying on one side of a certain diametral section flows in the opposite direction to that in conductors lying on the other side of the section. The invention is applicable where the beam is of large cross-sectional, e.g. in scanning devices in which an electron image corresponding with an optical image cast upon a photo-electric cathode is to be deflected. In one form, Fig. 1, the conductors 2 are so distributed as shown by the sizes of the dots and crosses, that a substantially homogeneous field 3 is produced. One deflecting coil may be placed within another to produce two mutually perpendicular deflections of the beam, and one or both coils may be adjustable about the tube axis. If the field is to diverge as shown in Fig. 4, for example, when a rectangular scan is required on a surface oblique to the direction of the undeflected beam, the current distribution is such that the average current density below the section line 7 is greater than that above. The coil may be situated within or outside the tube and may be wound on the ceramic support formed with indentations or grooves to receive the wires.