In-line electron gun

Claim 2

In a color picture tube including an evacuated envelope comprising a faceplate and a neck connected by a funnel, a mosaic color phosphor screen on the inner surface of said faceplate, a multiapertured color selection electrode spaced from said screen, an in-line electron gun mounted in said neck for generating and directing three electron beams along co-planar paths through said electrode to said screen, and a deflection zone, located in the vicinity of the junction between said neck and said funnel, wherein said beams are subjected to vertical and horizontal magnetic deflection fields during operation of said tube for scanning said beams horizontally and vertically over said screen; said electron gun comprising: a. means for generating and directing three electron beams along three co-planar paths towards said screen; b. means interposed between said first-named means and said deflection zone for focusing each beam near said screen and for converging the three beams near said screen; and c. a shielding member of magnetic material surrounding each of the outer ones only of said beam paths in siad deflection zone, for partially shielding only the two outer beams from said magnetic deflecting fields, thereby reducing the size of the rasters scanned by the outer beams without reducing the size of the raster scanned by the middle beam.

Claim 3

The structure of claim 1, wherein said electron gun further comprises a pair of magnetic elements positioned in said deflection zone on opposite sides of the middle beam path and in a plane transverse to the common plane of said paths for enhancing the magnetic deflection field in said middle beam path transverse to said common plane and for reducing the magnetic deflection field in said middle beam path along said common plane, thereby increasing the dimension of the raster scanned by the middle beam in said common plane while reducing the dimension of said raster in said transverse plane.

Claim 4

In a color picture tube including an evacuated envelope comprising a faceplate and a neck connected by a funnel, a mosaic color phosphor screen on the inner surface of said faceplate, a multi-apertured color selection electrode spaced from said screen, an in-line electron gun mounted in said neck for generating and directing three electron beams along co-planar paths through said electrode to said screen, and a deflection zone, located in the vicinity of the junction between said neck and said funnel, wherein said beams are subjected to vertical and horizontal magnetic deflection fields during operation of said tube for scanning said beams horizontally and vertically over said screen, and wherein the eccentrity of the outer ones of said beams in the deflection fields causes the sizes of the rasters scanned by the outer beams to tend to be larger than the size of the raster scanned by a middle beam, said electron gun comprising; a. means for generAting and directing three electron beams along three co-planar paths towards said screen; b. means interposed between said first-named means and said deflection zone for focusing each beam near said screen and for converging the three beams near said screen; and c. two shield rings of high magnetic permeability material located at the fringe of the deflection zone, each ring concentrically surrounding one of the outer beams, whereby small portions of the fringe deflection field are bypassed around the outer beams thereby reducing the size of the rasters scanned by the outer beams without reducing the size of the raster scanned by the middle beam.

Claim 5

In a color picture tube including an evacuated envelope comprising a faceplate and a neck connected by a funnel, a mosaic color phosphor screen on the inner surface of said faceplate, a multi-apertured color selection electrode spaced from said screen, an in-line electron gun mounted in said neck for generating and directing three electron beams along co-planar paths through said electrode to said screen, and a deflection zone, located in the vicinity of the junction between said neck and said funnel, wherein said beams are subjected to vertical and horizontal magnetic deflection fields during operation of said tube for scanning said beams horizontally and vertically over said screen, and wherein the eccentrity of the outer ones of said beams in the deflection fields causes the sizes of the rasters scanned by the outer beams to tend to be larger than the size of the raster scanned by a middle beam, said electron gun comprising; a. means for generAting and directing three electron beams along three co-planar paths towards said screen; b. means interposed between said first-named means and said deflection zone for focusing each beam near said screen and for converging the three beams near said screen; and c. two shield rings of high magnetic permeability material located at the fringe of the deflection zone, each ring concentrically surrounding one of the outer beams, whereby small portions of the fringe deflection field are bypassed around the outer beams thereby reducing the size of the rasters scanned by the outer beams without reducing the size of the raster scanned by the middle beam.

Claim 6

The tube as defined in claim 3, including two small discs of magnetic material located at the fringe of the deflection zone on opposite sides of the middle beam transverse to the plane of the three beams, whereby the magnetic flux on the middle beam transverse to the plane of the three beams is enhanced and the flux in the plane of the three beams is decreased thereby increasing the middle beam dimension in the plane of the three beams while reducing the middle beam dimension in the plane of the three beams.