Patent ID: 6313574
Filing Date: 2001-11-06
Classification: H01J

Abstract:
A color cathode-ray tube using a slot-type shadow mask in which a column of slots is constructed by linking approximately rectangular slot apertures in a direction parallel to the longitudinal direction of the slot by way of bridge portions, a plurality of said column of slots are lined up in the direction parallel to a lateral direction of the slot to form an active area;wherein a shape of a slot transmission aperture of said shadow mask is defined as the reference shape when the shape of the slot transmission aperture is rectangular; a longitudinal axis is defined as a line that lies within a plane containing a slot transmission aperture of reference shape and that is equidistant from two long sides of said slot transmission aperture; a lateral axis is defined as a line that lines within the plane containing said slot transmission aperture of reference shape, that is equidistant from two short sides, and that is perpendicular to the longitudinal axis; an intersection of said longitudinal axis and lateral axis is defined as a center of that slot transmission aperture; the direction parallel to said lateral axis is defined as a lateral direction; points of intersection of said long sides and said lateral axis are defined as the centers of the long sides; a side of said slot transmission aperture from which an electron beam exits is defined as the front side and the side into which an electron beam is incident is defined as the rear side; and the direction in which an angle of incidence of an electron beam on said active area increases is defined as outward;said shadow-mask type color cathode-ray tube including a shadow mask having a slot transmission aperture which defines a surface curving toward the front or rear side with respect to a prescribed reference plane, and has a bend in shape such that a position of each portion of said aperture is shifted in the lateral direction of said slot transmission aperture depending on a longitudinal position of the portion so as to compensate for deviation in the position of a projection of an electron beam onto a fluorescent screen from a designed position on the screen, said deviation being caused by a curvature of said surface.