TUB CINESCOP AUTOCONVERGENT PENTRU TELEVIZIUNE IN CULORI

摘要

1385745 Colour television tubes RCA CORPORATION 1 May 1972 [14 Jan 1972] 20047/72 Heading H1D A colour television tube of the shadow mask type using three co-planar beams, is provided with a deflection yoke adapted to produce a pin cushion shaped horizontal deflecting field which causes under convergence at extreme horizontal deflection, and a barrel-shaped vertical deflecting field which causes over-convergence at extreme vertical deflection; and the electron gun is adapted to produce a spacing between the beams at the centre of the deflection yoke not greater than 0À2 inch. Dynamic convergence arrangements are then unnecessary but may be provided for larger tubes. The electron gun may comprise three individual cathodes and common G1 to G4 electrodes provided with apertures for the beams; the outer apertures of the final electrode may be surrounded by magnetically permeable material such as nickel iron to partly screen the outer beams from the deflection fields and thereby equalize the raster sizes for the three colours. The deflection yoke is as described in Specification 1385747 and is preferaby toroidal but saddle coils may be used. The shadow mask may be provided with elongate apertures, and the fluorescent screen may comprise stripes of different colours.