GB836230A - Improvements in deflection coil assemblies for cathode ray tubes - Google Patents

Abstract

836,230. Electron beam deflecting apparatus. PYE Ltd. April 9, 1958 [April 16, 1957], No. 12403/57. Class 39(1). In a deflection coil system the line deflection ciols are of the saddle type and are wound so that they have a greater concentration of turns towards the outer edges of the two longitudinal limbs of each coil than along the adjacent edges of the two limbs, and the frame deflection ciols are toroidally wound outside the line deflection coils and have a greater concentration of turns at the centre of each coil than at the remote edges. In one embodiment a coil supporting member of a synthetic material such as polythene comprises two semi-cylindrical parts 1, Fig. 1 having flanges 1a, 1b and two saddle type line deflection coils 2 are located in the bore of members 1 by projections 1c. 'Flange la is flared to fit over the conical part of the cathode ray tube of a television receiver of the wide angle deflection type. The frame deflection coils 3 which are preferably wave wound are wound about a toroidal yoke 4 of magnetic material which may be in several sections as shown in Fig. 2 and are located by projections 1d on the outside of members 1. The line deflection coils 2 have a greater concentration of turns at the outer edges 2a of their longitudinal limbs than along their adjacent edges 2b, and the frame deflection coils which comprise two windings 3 have a greater concentration of turns at the centre 3a than at the remote edges 3b. The assembly is held together by an aluminium clamp 5, the two sections of the clamps surrounding yoke 4 inside coils 3. Pockets 7 may be provided for permanent magnets 8 to correct the shape of the raster produced by the coil assembly. An insulating band 9 may surround the assembly and carry tags 11 by which connection may be made to the coils.