Abstract: A fluorescent display tube, which has short-length filaments, can be driven by applied voltage of 3-8V to be used for a general fluorescent display tube. The fluorescent display tube can emit sufficient thermal electrons even if the number of filament cathodes is decreased to reduce power consumption of the filaments. The filament cathode is arranged between a first and third supporting plates by one end thereof fixed to the first supporting plate and the other end thereof fixed to the third supporting plate, and the filament cathode having an equal length with the filament cathode extended between the first and third supporting plates is arranged between the second and third supporting plates.

Abstract: A fluorescent display tube, which has short-length filaments, can be driven by applied voltage of 3-8V to be used for a general fluorescent display tube. The fluorescent display tube can emit sufficient thermal electrons even if the number of filament cathodes is decreased to reduce power consumption of the filaments. The filament cathode is arranged between a first and third supporting plates by one end thereof fixed to the first supporting plate and the other end thereof fixed to the third supporting plate, and the filament cathode having an equal length with the filament cathode extended between the first and third supporting plates is arranged between the second and third supporting plates.

Abstract: A double-faced vacuum fluorescent display of the invention is formed of an outer casing, and first and second display portions. The outer casing includes a base plate, a transparent front plate situated in front of the base plate, and a side member situated between the base plate and the front plate to form a space therebetween. The first display portion is mounted on the base plate, and includes a wiring pattern, an insulating layer with light shielding property, a first anode conductor and a first fluorescent layer. A display on the first display portion can be observed only from the front plate side. The second display portion is mounted on the transparent front plate, and includes a second anode conductor with transparency and a second fluorescent layer. The second display portion has a light transmitting portion for observing the first display portion therethrough.