Color cathode ray tube of the shadow mask variety

Claim 1

A shadow mask for a color cathode ray tube, said shadow mask having increased tolerance to permanent deformation caused by heat generated by impingement of an electron beam in a confined area for extended period of time, and comprising: a relatively rigid light weight frame of substantially rectangular configuration being formed to provide an inwardly extending flange having an attached side wall thereabout having a constant height; at least three areas of indentations formed in said side wall, one each being formed in the short sides and one in the long side of said frame; and a relatively fragile portion having a curved foraminated face and a solid skirt surrounding said face, a portion of said skirt being formed to provide a rectangular, peripheral, upstanding wall having four sides extending from said face and joined at the corners thereof, said four sides of said wall having a planar termination whereby the height of any one of said side walls is continuously variable when measured from adjacent points of said termination to said curved face, said peripheral wall of said foraminated face fitting over the outside of said frame side wall and being attached thereto by a plurality of welds spaced thereabout; each of said indentations having a leaf spring attached thereto, said springs having a flat area in contact with said indentations and having outwardly angled areas, said peripheral upstanding wall having slots in at least three of said sides corresponding to said indentations and said slots being positioned so that one edge of each of said slots lies on said flat area of said spring and the other edge of said slots lies between said springs and said indentations.