Cathode ray tube having improved shadow mask

Claim 2

In a cathode-ray tube of the vertical line screen, slit apertured mask type, the improvement comprising, the ratio of mask-to-screen spacing at the edge of the screen on the horizontal central axis to the mask-to-screen spacing at the center of the screen being in the range of 1.15 to 3.0.

Claim 3

The tube as defined in claim 1, including the horizontal spacing between apertures in the mask changing as a function of the change of the mask-to-screen spacing.

Claim 4

In a cathode-ray tube comprising an evacuated envelope including a faceplate, a color phosphor line screen including a plurality of arrays of substantially parallel vertical phosphor lines affixed to an inner surface of said faceplate, the phosphor lines in each array being adapted to emit light of a particular color, an apertured mask spaced from said screen, said apertured mask having a plurality of substantially parallel vertical columns of apertures elongated in the direction of said columns, and means for generating and directing a plurality of electron beams through the apertures of said mask to said screen, the improvement comprising, the spacing between the centerlines of adjacent columns of apertures and the spacing between the apertured mask and said screen both varying in relation to each other and increasing from center to edge of said mask along the horizontal axis thereof.

Claim 5

In a cathode-ray tube comprising an evacuated envelope including a faceplate, a color phosphor line screen including a plurality of arrays of substantially parallel vertical phosphor lines affixed to an inner surface of said faceplate, the phosphor lines in each array being adapted to emit light of a particular color, an apertured mask spaced from said screen, said apertured mask having a plurality of substantially parallel vertical columns of apertures elongated in the direction of said columns, and means for generating and directing a plurality of electron beams through the apertures of said mask to said screen, the improvement comprising, the spacing between the centerlines of adjacent columns of apertures and the spacing between the apertured mask and said screen both varying in relation to each other and increasing from center to edge of said mask along the horizontal axis thereof.

Claim 6

The cathode-ray tube as defined in claim 3, wherein the width of the mask apertures are substantially constant over said mask.

Claim 7

The cathode-ray tube as defined in claim 3, wherein the width of the mask apertures are greater at the edges of said mask at the ends of the horizontal axis than in the center of said mask.

Claim 8

The cathode-ray tube as defined in claim 3, wherein the ratio of mask-screen spacing at the edges of said mask at the ends of the horizontal axis to the mask-screen spacing at the center of the mask is in the range of 1.15 to 3.0.

Claim 9

The cathode-ray tube as defined in claim 6, wherein said ratio is approximately 1.5.

Claim 10

The cathode-ray tube as defined in claim 3, wherein the horizontal edge-to-edge spacing between apertures is varied over said mask to provide visually acceptable packing of the phosphor lines.

Claim 11

The cathode-ray tube as defined in claim 3, wherein said faceplate is substantially flat and said mask is curved.

Claim 12

The cathode-ray tube as defined in claim 9, wherein the rate of change of spacing between said mask and said screen changes at least once from the center of said mask to the outer edges of said mask at the ends of the horizontal axis.

Claim 13

In a cathode-ray tube with a substantially flat faceplate utilizing an apertured mask color selection technique for registering a plurality of inline electron beams on phosphor elements of a cathodoluminescent line screen, said tube having structural relationships which approximately satisfy the formula q = La/3s in which "q" is the spacing between the mask and the cathodoluminescent screen of said tube, "L" is the spacing between a plane of deflection of said tube and said screen, "a" is the center-to-center spacing of adjacent mask apertures, and "s" is the spacing between an off axis electron beam path and the central tube axis in the plane of deflection, the improvement comprising, said apertured mask being curved and having a convex side facing said faceplate wherein the "q" spacing is a minimum at the center of said mask and is greatest at the periphery of said mask and, the horizontal "a" spacing is constant along the central horizontal axis of said mask and increases in relation to the increase in the "q" spacing above and below the central horizontal axis.

Claim 14

In a cathode-ray tube with a substantially flat faceplate utilizing an apertured mask color selection technique for registering a plurality of inline electron beams on phosphor elements of a cathodoluminescent line screen, said tube having structural relationships which approximately satisfy the formula q = La/3s in which "q" is the spacing between the mask and the cathodoluminescent screen of said tube, "L" is the spacing between a plane of deflection of said tube and said screen, "a" is the center-to-center spacing of adjacent mask apertures, and "s" is the spacing between an off axis electron beam path and the central tube axis in the plane of deflection, the improvement comprising, said apertured mask being curved and having a convex side facing said faceplate wherein the "q" spacing is a minimum at the center of said mask and is greatest at the periphery of said mask and, the horizontal "a" spacing is constant along the central horizontal axis of said mask and increases in relation to the increase in the "q" spacing above and below the central horizontal axis.

Claim 15

In a cathode ray tube of the line screen-inline gun type, the improvement comprising, the spacing between an apertured mask of said tube and a screen of said tube being approximately 1.5 times greater at an off-center point on the screen than at the center of the screen.

Claim 16

In a cathode ray tube of the line screen-inline gun type, the improvement comprising, the spacing between an apertured mask of said tube and a screen of said tube being approximately 1.5 times greater at an off-center point on the screen than at the center of the screen.