PURPOSE: To prevent a resolving power and contrast from being deteriorated in a tube, by using a thin film, made of material with a high electron transmittivity, as a support film, evaporating an aluminum onto the surface of said film and forming a fluorescent material layer.

CONSTITUTION: Output screen support frame 11 provide an opening port 12 of area corresponding to the area of an output fluorescent screen and are fixed to the inner face of a glass vessel 1 or to a suitable fixed support. Fully on surfaces of the opening port 12 of the support frame 11 an auminum support film 13 is extensibly attached and then on its surface an aluminum 14 is evaporated to a thickness in a range 600W1,200 further on its top a fluorescent material layer 15 is formed.