Rectangular shadow mask for colour CRT - consists of perporated thin metal sheet with bent edge fitting over frame of thicker metal

摘要

The rectangular shadow mask is for a colour c.r.t. and consists of a perforated thin metal sheet with a bent edge. This edge fits over a frame made of a thicker metal. It is fastened to it in several places. The edge has holes or recesses while the frame has fastening elements for holding the shadow-mask in the tube. The holes or recesses in the shadow-mask's short side edge form strips supporting the shadow-mask and run parallel to each other and to the symmetry plane. They run in the middle part of the long side parallel to the symmetry plane, but slope progressively towards the mask corners.