A display tube has an evacuated envelope with a display panel, a cone (or
funnel) portion and a neck portion. The cone portion has a cone body
portion and a parabolic portion. The contour of the cone body in a plane
through the longitudinal axis of the tube and the short axis of the panel
is such that up to at least half the length of the cone body the cone
height sinks by maximally 12%. Hereby stresses at the sealing face
between the panel and the cone portion arc reduced. More in particular
the Z and Y coordinates of the outer contour are such that at 0.5L=Z it
holds that 0.88H