Patent ID: 6504298
Filing Date: 2003-01-07
Classification: H01J

Abstract:
A picture display device having an evacuated envelope (1), which envelope comprises, around a longitudinal axis (20), a display window (2) with a display screen (3) on its inner side, a conical portion (4) and a neck portion (5), the conical portion being connected to an upstanding wall (15) of the display window (2), characterized in that, along a diagonal in a direction from the neck portion (5) to one of the corners of the display window (2), the wall thickness d60% of the conical portion (4) at a distance of 60% between the transition in the conical portion from at least substantially axial symmetry to a lower symmetry and the connection to the upstanding wall (15) of the display window (2), which distance is measured with respect to the projection on the longitudinal axis (20), is defined by the relation:d60%=dseâˆ’&agr;(dseâˆ’dpa), in which the coefficient &agr; is in the range of 0.4&lE;&agr;&lE;1, and in which dse is the wall thickness of the conical portion (4) at the area of the transition between the conical portion (4) and the upstanding wall (15), and dpa is the wall thickness of the conical portion (4) at the area of said transition in the conical portion, the conical portion (4) is provided with a coating (17) of a thickness of less than 50 &mgr;m where the value of the coefficient &agr; is >0.6 and the upstanding wall (15) of the display window (2) is provided with the coating (17).