Grid structure for color picture tube

Abstract

In a grid structure for a color picture tube of the type comprised of a pair of elongated frame elements disposed in substantially parallel, spaced apart relation at the top and bottom, respectively, of the grid structure, a pair of mechanically resilient brace members having mid-portions extending between the frame elements at the opposite sides of the grid structure and end portions affixed to the frame elements for maintaining the latter in their spaced apart relation, and a plurality of grid wires defining slits therebetween extending between the frame elements and being welded or otherwise affixed to the latter adjacent the opposite ends of the grid wires while the grid wires are longitudinally tensioned and the brace members are prestressed by forces acting on the frame elements in the directions to urge the frame elements toward each other; each brace member has a cross-sectional shape, such as, a rectangular shape, providing different section moduli in respect to correspondingly different axes passing through the centroid of the cross-sectional shape, and the mid-portion of each brace member is disposed so that an axis of the cross-sectional shape thereof which passes through the centroid at right angles to the axis about which there is a maximum section modulus is disposed in a plane containing the lines of action of the forces which act on the frame elements at predetermined points adjacent the respective end portions of the frame elements, for example, the points at which forces are applied to the frame elements for prestressing the brace members during the affixing of the grid wires to the frame elements.