Cathode-ray tube having a faceplate panel with a substantially planar periphery

A cathode-ray tube including a rectangular faceplate wherein a long side of the faceplate substantially parallels a major axis of the tube and a short side of the faceplate substantially parallels a minor axis of the tube, said faceplate having an exterior surface having curvature along both said minor and major axes and wherein said exterior surface includes a substantially rectangular contour near the periphery of said faceplate which substantially lies in a plane that is perpendicular to the central longitudinal axis of said tube and wherein the equation of the line formed by the center-to-corner contour of the cross-section of said exterior surface has at least one sign change of its second derivative.