Beam penetration color cathode ray tube

Claim 1

A CATHODE RAY TUBE COMPRISING A LUMINESCENT VIEWING SCREEN AND AN ELECTRON GUN ASSEMBLY INCLUDING THREE ELECTRON GUNS DISPOSED SIDE-BY-SIDE IN DELTA ARRAY AND FOR PRJECTING THREE DIFFERENT VELOCITY ELECTRON BEAMS TOWARD SAID SCREEN THROUGH A COMMON DEFLECTION ZONE FOR ESTABLISHING A COMMON DEFLECTION FIELD THEREIN, A FIRST MAGNETIC TUBULAR SHEILD SURROUNDING THE PATH OF A FIRST ONE OF SAID BEAMS IN SAID DEFLECTION FIELD THEREIN, A FIRST MAGNETIC TUBULAR SHIELD SURROUNDING THE PATH OF A FIRST ONE OF SAID SAID BEAMS IN SAID DEFLECTION ZONE, ONE OF SAID SHIELDS BEING SHORTER AND OF LARGER DIAMETER THAN THE OTHER AND AXIALLY DISPOSED BETWEEN AND SPACED FROM THE ENDS OF SAID OTHER SHIELD, THE RELATIVE LENGTHS, RELATIVE DIAMETERS, AND RELATIVE AXIAL DISPOSITIONS OF SAID SHIELDS BEING SUCH THAT FOR GIVEN BEAM VELOCITIES AND A GIVEN FIELD SHAPE AND STRENGTH, SUBSTANTIALLY EQUAL SIZE RASTERS ARE SCANNED BY THE THREE BEAMS AND THE DEFLECTION FIELD DISTORTIONS CAUSED BY THE TWO SHIELDS HAVE SUBSTANTIALLY CORRESPONDING EFFECTS ON THE RASTER OF THE THIRD BEAM WHICH IS SCANNED THROUGH THE TWO FIELD DISTORTIONS.