An electron emitter that consists of: a low work function material including Lanthanum hexaboride or Iridium Cerium that acts as an emitter, a cylinder base made of high work function material that has a cone shape where the low work function material is embedded in the high work function material but is exposed at end of the cone and the combined structure is heated and biased to a negative voltage relative to an anode, an anode electrode that has positive bias relative to the emitter, and a wehnelt electrode with an aperture where the cylindrical base protrudes through the wehnelt aperture so the end of the cone containing the emissive area is placed between the wehnelt and the anode.

An electron emitter that consists of: a low work function material including Lanthanum hexaboride or Iridium Cerium that acts as an emitter, a cylinder base made of high work function material that has a cone shape where the low work function material is embedded in the high work function material but is exposed at end of the cone and the combined structure is heated and biased to a negative voltage relative to an anode, an anode electrode that has positive bias relative to the emitter, and a wehnelt electrode with an aperture where the cylindrical base protrudes through the wehnelt aperture so the end of the cone containing the emissive area is placed between the wehnelt and the anode.

A vacuum tube includes a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emits thermoelectrons. Both of the anodes are formed on a same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode of a same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube further includes an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.

A vacuum tube includes a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emits thermoelectrons. Both of the anodes are formed on a same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode of a same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube further includes an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.

A vacuum tube includes a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emits thermoelectrons. Both of the anodes are formed on a same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode of a same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube further includes an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.

A vacuum tube includes a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emits thermoelectrons. Both of the anodes are formed on a same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode of a same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube further includes an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.

An object of the present invention is to provide a vacuum tube with a structure close to that of an inexpensive and easily available vacuum fluorescent display which easily operates as an analog amplifier. A vacuum tube subject to the present invention comprises: a filament which is tensioned linearly and emits thermoelectrons, an anode arranged parallel to the filament, and a grid arranged between the filament and the anode such that the grid faces the anode. The present invention is characterized in that a distance between the filament and the grid is between 0.2 mm and 0.6 mm, including 0.2 mm and 0.6 mm.

An object of the present invention is to provide a vacuum tube with a structure close to that of an inexpensive and easily available vacuum fluorescent display which easily operates as an analog amplifier. A vacuum tube subject to the present invention comprises: a filament which is tensioned linearly and emits thermoelectrons, an anode arranged parallel to the filament, and a grid arranged between the filament and the anode such that the grid faces the anode. The present invention is characterized in that a distance between the filament and the grid is between 0.2 mm and 0.6 mm, including 0.2 mm and 0.6 mm.

The vacuum tube subject to the present invention comprises a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emitting thermoelectrons. Both of the anodes are formed on the same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode in the same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube comprises an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.

The vacuum tube subject to the present invention comprises a filament and two pairs of a grid and an anode. The filament is tensioned linearly and emitting thermoelectrons. Both of the anodes are formed on the same face on a planar substrate. The filament is arranged parallel to the planar substrate at a position facing both of the anodes. Each of the grids is arranged, such that the grid faces the anode in the same pair at a first predetermined distance from the anode and has a second predetermined distance from the filament, between the anode and the filament. The vacuum tube comprises an intermediate filament fixing part fixing the filament at a position corresponding to an intermediate point between the anodes of the two pairs.