Abstract: A shadow mask has a major axis H and a minor axis V that intersect at right angles with each other, and a curvature along the major axis is set to satisfy the following relationships, Cxm0<Cxmv, and Cxmd<Cxmh where Cxm0 is a curvature at an origin O where the major axis and the minor axis intersect at right angles, Cxmv is a curvature at a point (0, Ymvi) that is located towards a long side from a point of at least ¾ of a distance from the origin on the minor axis to an end of an effective dimension, Cxmh is a curvature at a point (Xmhi, 0) that is located in a region of 2/4 to ¾ of a distance from the origin on the major axis to an end of an effective dimension, and Cxmd is a curvature at a coordinate point (Xmhi, Ymvi).

Abstract: A mask frame comprises a sidewall portion in the form of a rectangular frame including a pair of long sidewalls opposed to each other, a pair of short sidewalls opposed to each other, and corner sidewalls between the long and short sidewalls, and a base portion extending from the sidewall portion toward the center of the rectangular frame. The base portion has beads located near the corner sidewalls and connecting the long and short sidewalls.

Abstract: A main body 34 of a shadow mask is opposed to a phosphor screen and is formed in a substantially rectangular shape. The main body 34 has a main surface portion 31 where a number of electron beam apertures are formed, and a skirt portion 33 provided around the main surface portion with a non-aperture portion 32 interposed between the skirt portion and the main surface portion. A plurality of rectangular openings 38a extending in the long axis direction (or X-direction) of the mask body are formed at the skirt portion. Concave portions 47 extending in the long axis direction (X-direction) of the mask body are formed at the non-aperture portion. The openings and concave portions are provided within a range of about ¼ of the length W of the mask body in the long axis direction, with respect to a center of the range defined at a position distant from the short axis Y by about ⅓ of the length W of the long axis direction of the mask body.

Abstract: A mask frame comprises a sidewall portion in the form of a rectangular frame including a pair of long sidewalls opposed to each other, a pair of short sidewalls opposed to each other, and corner sidewalls between the long and short sidewalls, and a base portion extending from the sidewall portion toward the center of the rectangular frame. The base portion has beads located near the corner sidewalls and connecting the long and short sidewalls.

Abstract: A substantially rectangular shadow mask is arranged opposite to a phosphor screen formed on an inner surface of a panel. The shadow mask has a mask body and a mask frame to which a peripheral portion of the mask body is attached. The shadow mask has a rectangular form having a center through which a tube axis passes, and a long axis and a short axis passing through the center and perpendicular to each other. The mask frame has a pair of long side walls extending parallel to the long axis and a pair of short side walls extending parallel to the short axis. The height of each long side wall at a central portion along the tube axis is lower than the height of each short side wall at a central portion along the tube axis.

Abstract: A shadow mask opposed to a phosphor screen has a substantially rectangular effective surface (30) where slit-like apertures are formed. The apertures are disposed so as to constitute a plurality of aperture rows which extend in parallel with the short axis of the effective surface and are disposed in the long axis of the effective surface. Each of the aperture rows includes a plurality of aperture, and bridges (38) positioned between any adjacent pair of the apertures. The width B of the bridges in the lengthwise direction of the aperture rows, positioned an intermediate between the short axis of the effective surface and a short side edge thereof is greater than that of the bridges positioned at a peripheral portion of the effective surface.