Patent ID: 7368865

Claim:
A picture display device comprising a display tube having an evacuated envelope, which envelope comprises, arranged along a longitudinal axis, a display panel having a short axis and a long axis, provided with a display screen on its inner side, a conical portion and a neck portion, the conical portion being connected to an upstanding wall of the display panel through a seal edge, the conical portion having a yoke area having a parabolic curvature, the conical portion being connected to the neck portion, characterized in that the cross section of the conical portion in a plane through the longitudinal axis and the short axis of the panel has an outer contour comprising a first area of the conical portion adjacent to the upstanding wall of the display panel which transverses into a second area of the conical portion adjacent to a position where the parabolic curvature of the yoke area ends, the outer contour having Z and Y coordinates in said plane, the coordinates being defined with respect to an origin positioned at the crossing of the short axis and the longitudinal axis, the outer contour passing through coordinates having values of Z and Y being defined such that at 0.5L=Z, 0.88H<Y<H, wherein H is a position of the seal edge on the short axis, L is the depth of the conical portion along the longitudinal axis from the seal edge towards the position where the parabolic curvature of the yoke area ends, Z is a value along the direction of the longitudinal axis, and Y is a value along the direction of the short axis.