Color cathode-ray tube including a shadow mask having holes arranged with a monotonically non-decreasing arrangement pitch

A color cathode-ray tube comprising:

• an envelope having a panel portion, a neck portion, and a funnel portion coupling said panel portion and said neck portion to each other;
• an electron gun mounted within said neck portion for producing electron beams;
• a phosphor screen formed on an inner surface of said panel portion;
• and
• a shadow mask having a plurality of holes therein and disposed opposing said phosphor screen so that said electron beams pass through holes in said shadow mask to impinge on said phosphor screen;
• wherein said holes are arranged with a varying arrangement pitch, said varying arrangement pitch being monotonically non-decreasing from a central portion to two opposite peripheral portions of said shadow mask as viewed, in a horizontal direction in the color cathode-ray tube, at an arbitrary position on said shadow mask in a vertical direction in the color cathode-ray tube;
• wherein an increase of said varying arrangement pitch in said horizontal direction is substantially zero in first regions from said central portion to intervening portions between said central portion and said two opposite peripheral portions of said shadow mask;
• wherein an increase of said varying arrangement pitch in said horizontal direction has a gradient not smaller than zero in second regions from said intervening portions toward said two opposite peripheral portions of said shadow mask;
• wherein a distance between said central portion and each of said two opposite peripheral portions of said shadow mask is L.sub.x ;
• wherein a distance between said central portion and each of said intervening portions is at least L.sub.x /2 and not more than 2L.sub.x /3;
• wherein said varying arrangement pitch at said central portion is Ph.sub.0 ;
• and
• wherein said varying arrangement pitch in said first regions is at least Ph.sub.0 and not greater than 1.005 Ph.sub.0.

A shadow mask for use in a color cathode-ray tube, said shadow mask comprising:

• a metal plate in which a plurality of holes are formed for passage of electron beams therethrough in the color cathode-ray tube, said holes being arranged with a varying arrangement pitch, said varying arrangement pitch being monotonically non-decreasing from a central portion to two opposite peripheral portions of said shadow mask as viewed, in a first direction conforming with a horizontal direction in the color cathode-ray tube, at an arbitrary position on said shadow mask in a second direction perpendicular to said first direction;
• wherein an increase of said varying arrangement pitch in said first direction is substantially zero in first regions from said central portion to intervening portions between said central portion and said two opposite peripheral portions of said shadow mask;
• wherein an increase of said varying arrangement pitch in said first direction has a gradient not smaller than zero in second regions from said intervening portions toward said two opposite peripheral portions of said shadow mask;
• wherein a distance between said central portion and each of said two opposite peripheral portions of said shadow mask is L.sub.x ;
• wherein a distance between said central portion and each of said intervening portions is at least L.sub.x /3 and not more than 2L.sub.x /3;
• wherein said varying arrangement pitch at said central portion is Ph.sub.0 ;
• wherein said varying arrangement pitch in said first regions is at least Ph.sub.0 and not greater than 1.005 Ph.sub.0 ;
• wherein a radius of curvature of a cross-section of said shadow mask taken along said first direction is substantially constant in said first regions from said central portion to said intervening portions, and gradually decreases in said second regions from said intervening portions toward said two opposite peripheral portions of said shadow mask;
• wherein said radius of curvature is R1 at said central portion, substantially R1 at said intervening portions, and R2 at said two opposite peripheral portions of said shadow mask;
• and
• wherein R1/R2 is substantially 1.98.

A color cathode-ray tube comprising:

• an envelope having a panel portion, a neck portion, and a funnel portion coupling said panel portion and said neck portion to each other;
• an electron gun mounted within said neck portion for producing electron beams;
• a phosphor screen formed on an inner surface of said panel portion;
• and
• a shadow mask having a plurality of holes therein and disposed opposing said phosphor screen so that said electron beams pass through holes in said shadow mask to impinge on said phosphor screen;
• wherein said holes are arranged with a varying arrangement pitch, said varying arrangement pitch being monotonically non-decreasing from a central portion to two opposite peripheral portions of said shadow mask as viewed, in a horizontal direction in the color cathode-ray tube, at an arbitrary position on said shadow mask in a vertical direction in the color cathode-ray tube;
• wherein an increase of said varying arrangement pitch in said horizontal direction is substantially zero in first regions from said central portion to intervening portions between said central portion and said two opposite peripheral portions of said shadow mask;
• wherein an increase of said varying arrangement pitch in said horizontal direction has a gradient not smaller than zero in second regions from said intervening portions toward said two opposite peripheral portions of said shadow mask;
• wherein a distance between said central portion and each of said two opposite peripheral portions of said shadow mask is L.sub.x ;
• wherein a distance between said central portion and each of said intervening portions is at least L.sub.x /3 and not more than 2L.sub.x /3;
• wherein said varying arrangement pitch at said central portion is Ph.sub.0 ;
• wherein said varying arrangement pitch in said first regions is at least Ph.sub.0 and not greater than 1.005Ph.sub.0 ;
• wherein a radius of curvature of a cross-section of said shadow mask taken along said horizontal direction is substantially constant in said first regions from said central portion to said intervening portions, and gradually decreases in said second regions from said intervening portions toward said two opposite peripheral portions of said shadow mask;
• wherein said radius of curvature is R1 at said central portion, substantially R1 at said intervening portions, and R2 at said two opposite peripheral portions of said shadow mask;
• and
• wherein R1/R2 is substantially 1.98.