Foil shadow mask mounting with low thermal expansion coefficient

Abstract

A mounting arrangement for a foil shadow mask includes a plurality of elongated, generally linear spacers affixed to an inner surface of the flat glass faceplate of a color cathode ray tube (CRT) and arranged in a generally rectangular array. Attached to each spacer substantially along the length thereof is a respective elongated mounting spring. Each mounting spring includes a first portion attached to its associated spacer and a second flexible, resilient U-shaped portion to which a mask anchor is securely attached. Each peripheral edge portion of the foil shadow mask is attached to a respective mask anchor for maintaining the foil shadow mask in registration with light emitting phosphor elements on the CRT's faceplate. The mounting springs allow the glass faceplate as well as glass-based spacers to which the mounting springs are attached to expand during high temperature processing encountered in CRT fabrication without exceeding the foil shadow mask's tensile stress limits while maintaining the foil shadow mask in registration with the phosphor elements during lower temperature operation. Another embodiment contemplates a monolithic bi-metallic structure attached to the glass faceplate as well as to the foil shadow mask which is inflexible at lower operating temperatures to maintain the foil shadow mask in registration yet flexes at higher CRT processing temperatures during manufacture to allow for expansion of the glass faceplate without exceeding mask tensile stress limits.