Glass Case for Cathode Ray Tubes

Cathode ray tube for which the front face is flat and/or for which the deflection angle is greater than 110°. The tube comprises a front panel supporting a luminescent screen surrounded by a flange perpendicular to the panel, the said panel being defined by: a thickness t at the corner of the screen, a distance t 1 between the corner of the screen and the free edge of the flange, a rear part in the form of a funnel, whose tapered free edge is arranged at the distance t 2 from the reference line of the tube. The tube is characterized by values of t, t 1 , t 2 chosen in such a manner that the ratio A=(t 1 +/t)/t 2 is between the range of values [0.0061Thetam-7.8 10-6(Thetam)2±0.05]. for which Thetam is expressed in degrees. Hence, the quantity of glass reduced while providing the mechanical strength necessary for resisting the application of a vacuum to the tube.