EP0456550A1 - Electron tube with cylindrical grid - Google Patents

Electron tube with cylindrical grid Download PDF

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Publication number
EP0456550A1
EP0456550A1 EP91401116A EP91401116A EP0456550A1 EP 0456550 A1 EP0456550 A1 EP 0456550A1 EP 91401116 A EP91401116 A EP 91401116A EP 91401116 A EP91401116 A EP 91401116A EP 0456550 A1 EP0456550 A1 EP 0456550A1
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EP
European Patent Office
Prior art keywords
grid
mesh
cathode
bars
meshes
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Granted
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EP91401116A
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German (de)
French (fr)
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EP0456550B1 (en
Inventor
Michel-Pierre Tardy
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Thales Electron Devices SA
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Thomson Tubes Electroniques
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
    • H01J19/28—Non-electron-emitting electrodes; Screens
    • H01J19/38—Control electrodes, e.g. grid
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J21/00—Vacuum tubes
    • H01J21/02—Tubes with a single discharge path
    • H01J21/06—Tubes with a single discharge path having electrostatic control means only
    • H01J21/10—Tubes with a single discharge path having electrostatic control means only with one or more immovable internal control electrodes, e.g. triode, pentode, octode

Definitions

  • the present invention relates to cylindrical concentric power electrode tubes. These tubes are, for example, triodes or tetrodes.
  • a triode tube mainly comprises a central cylindrical cathode emitting electrons when it has reached a sufficient temperature, a control grid around the cathode, an anode surrounding the control grid.
  • the electrons emitted by the cathode pass through the grid and reach the anode, if the potential of the grid and the anode have appropriate values.
  • the tetrodes have an additional grid, called a screen grid inserted between the control grid and the anode.
  • the cathode is often made from two layers of emissive metallic wires which are crossed in order to obtain a mesh.
  • the assembly thus produced has a cylindrical structure. Each end of the cylinder is fixed on a support. These cathodes are called cages.
  • the grids are also meshed. They can be made from sheets of son of a refractory material which is crossed in order to obtain a mesh. The wires are welded together at each intersection. The assembly thus formed has a cylindrical structure and its ends are connected to supports.
  • a second way of making a grid is to take a sheet of refractory material, in the shape of a cylinder, and to pierce it with regularly spaced openings in order to obtain the mesh.
  • pyrolitic graphite or molybdenum is commonly used as refractory material.
  • Each mesh is defined by a succession of bars connected by their ends and the intersection between two bars is a knot.
  • the cathode and the grids because of this very cut structure, are subject to vibrations affecting their mechanical stability.
  • the distance between the cathode and the control grid is small, generally less than 1000 micrometers, and the vibrations which may occur cause appreciable variations in this distance. These vibrations are detrimental to the proper functioning of the tube.
  • the same remarks apply to intergrid distances in the case of tetrodes or other multigrid tubes.
  • the importance of mechanical stability will be measured, adding that the cathode can operate at a high operating temperature (of the order of 1700 ° C.) and that it must also have good resistance to deformation.
  • the grids will reach a lower temperature (around 1200 ° C) but must also have good resistance to deformation
  • An ideal grid in terms of potential and transparency would have an infinity of vertical and very fine wires.
  • the gate current would be very low and the gate potential distributed very regularly around the cathode.
  • this grid would have extremely poor mechanical strength, especially if it had large dimensions.
  • the grids used frequently have meshes in the form of quadrilaterals: square, rectangle, rhombus or parallelogram. From a knot of mesh leave four bars.
  • the present invention aims to remedy these drawbacks and proposes a grid tube operating with a reduced grid current. To do this, we sought to minimize the interception surface of the electrons, without harming either the mechanical stability or the distribution of the gate potential around the cathode.
  • the present invention relates to an electronic tube with concentric cylindrical electrodes among which a central cathode and at least one grid of the mesh type, a mesh being defined by several bars in contact at their ends, characterized in that the meshes have the shape of a hexagon .
  • the meshes are substantially identical.
  • the hexagons are substantially regular.
  • this grid surrounds a cathode with diamonds-forming wires, the intersection between two cathode wires is aligned with the central part of a grid mesh.
  • the rod and the wire are perpendicular to minimize the overlap area.
  • the meshes are produced from a sheet of refractory material in the form of a cylinder pierced with hexagonal orifices.
  • the material can be pyrolitic graphite or molybdenum.
  • FIG. 1a represents a mesh in parallelogram of an electron tube grid, of the triode type for example.
  • Figure 1b shows it, a diamond mesh.
  • Each of these meshes can be produced from two plies of wires 1,2 which are substantially parallel, which are superimposed by crossing them.
  • the wires 1 of a ply are then welded to the wires 2 of the other ply, at all the crossing points.
  • Each crossing forms a knot 3. From each node 3 leave four bars 5.
  • a mesh 4 consists of four bars 5.
  • a mesh 4 has the shape of a parallelogram, it consists of four equal bars, two by two.
  • a mesh 4 has the shape of a rhombus, it consists of four equal bars 5.
  • the wires 1,2 used to make these grids are made of refractory metal, for example molybdenum.
  • a grid of this type can also be made from a sheet of refractory material of graphite or molybdenum for example.
  • the sheet is pierced with openings by any known means, machining, sandblasting or EDM, for example.
  • the openings are preferably regularly spaced and have an appropriate shape to obtain the mesh.
  • An electron tube grid for example a triode, is cylindrical and it is mounted around a cathode emitting electrons. The electrons pass through the grid when the latter is brought to a negative potential compared to that of the cathode.
  • the bars 5 and the nodes 3 form an electron screen.
  • Certain electrons are intercepted by the structure of the grid when it is brought to a positive potential compared to that of the cathode. The intercepted electrons cause the appearance of a gate current.
  • a high grid current causes an excessive increase in the temperature of the grid and requires the use of a powerful grid supply.
  • FIG. 3 represents a regular hexagonal mesh of an electron tube grid according to the invention. This mesh has nodes 36. From each node 36, only three bars 35 leave.
  • each mesh 34 is hexagonal, it is defined by six bars 35 connected by their ends.
  • the surface of the nodes 36 has been reduced compared to the meshes conventionally used.
  • the electrons intercepted by a grid of this type will be fewer and an electronic power tube having a grid of this type will have a reduced grid current compared to the grid current of a conventional power tube.
  • each mesh 34 is made up of equal bars 35 and two successive bars 35 make an angle of 120 °. All the meshes are substantially identical.
  • FIG. 5 is a view of a mesh grid of electronic tube according to the invention.
  • the grid has 50 regular hexagonal meshes. It has a honeycomb structure. It comprises a meshed part 51 of cylindrical shape. The two ends 52 of the cylinder are each held on a support 53.
  • the grid will be produced from a sheet of refractory material, for example pyrolitic graphite, molybdenum, in the form of a cylinder.
  • a sheet of refractory material for example pyrolitic graphite, molybdenum
  • We cut holes. in this sheet by any known means, machining, sandblasting, EDM, for example.
  • the orifices are distributed regularly over the entire sheet. They are given the shape of hexagons. We obtain a hexagonal mesh. Each end of the cylinder is fixed on a support.
  • the interception surface has been reduced, at the level of the nodes, if we compare it to that of the grids with triangular meshes and meshes in the form of a quadrilateral.
  • the regularity of the hexagons and their orientation are chosen according to the mechanical and electrical parameters that the grid must have.
  • the geometry of the bars that is to say their length and their cross section, as well as the angle of intersection between two bars are chosen so as to ensure transparency to the electrons and a control of the potential around the cathode, corresponding to the characteristics that the tube must have.
  • a regular hexagonal mesh allows smaller meshes than those usually used. This results in better control of the potentials between the bars and near the cathode (if the grid is a control grid), an improvement in the tube blocking voltage or "cutt off" as well as a better distribution of the electron trajectories.
  • a regular hexagonal mesh allows larger meshes than those usually used. This results in greater transparency of the grid and a reduction in the grid current, in particular in high power operation.
  • FIG. 6 represents a mesh 60 of a cage cathode covered with a mesh 70 of the control grid of an electronic tube according to the invention.
  • the cathode mesh 60 consists of two groups of wires 61, 62 which are substantially parallel, the two groups being crossed. We made 63 diamond shaped meshes.
  • the wires 61, 62 of the cathode emit electrons when they are heated.
  • An intersection 64 between two wires 61, 62 has a large surface which emits a high density of electrons.
  • the grid mesh 70 comprises hexagonal and regular meshes 65 made up of bars 66.
  • all the grids will be aligned with one another and will be identical, so that the intersection 64 between two cathode wires 61, 62 is placed in the central part of all the grid meshes.
  • the invention applies both to control grids and to other grids (screen grid, stop grid %)
  • This type of hexagonal mesh is particularly suitable for tubes in which the interelectrode distance is small because the mesh offers very good mechanical stability and very good resistance to deformation.
  • the hexagonal mesh makes it possible to minimize the grid current and to properly control the potential between the bars.
  • a grid with hexagonal meshes can advantageously be integrated into a tube of high gain and low attack power.

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Abstract

The invention relates to electron tubes with concentric cylindrical electrodes. <??>This tube includes at least one grid of mesh type, a grid cell (34) being defined by several bars (35) in contact via their ends, each point of contact producing a node (36). <??>So as to limit grid current, the area of a node is reduced. Only three bars (35) leave each node (36). The mesh cells (34) are hexagonal. <??>Application to power tubes of triode or tetrode type. <IMAGE>

Description

La présente invention concerne les tubes à électrodes cylindriques concentriques de puissance. Ces tubes sont, par exemple, des triodes ou des tétrodes.The present invention relates to cylindrical concentric power electrode tubes. These tubes are, for example, triodes or tetrodes.

Un tube triode comporte principalement une cathode cylindrique centrale émettant des électrons lorsqu'elle a atteint une température suffisante, une grille de commande autour de la cathode, une anode entourant la grille de commande. Les électrons émis par la cathode passent à travers la grille et atteignent l'anode, si le potentiel de la grille et de l'anode ont des valeurs appropriées. Les tétrodes comportent une grille supplémentaire, dite grille-écran insérée entre la grille de commande et l'anode.A triode tube mainly comprises a central cylindrical cathode emitting electrons when it has reached a sufficient temperature, a control grid around the cathode, an anode surrounding the control grid. The electrons emitted by the cathode pass through the grid and reach the anode, if the potential of the grid and the anode have appropriate values. The tetrodes have an additional grid, called a screen grid inserted between the control grid and the anode.

La cathode est souvent réalisée à partir de deux nappes de fils métalliques émissifs que l'on croise afin d'obtenir un maillage. L'ensemble ainsi réalisé a une structure cylindrique. On fixe chaque extrémité du cylindre sur un support. Ces cathodes sont dites en cage.The cathode is often made from two layers of emissive metallic wires which are crossed in order to obtain a mesh. The assembly thus produced has a cylindrical structure. Each end of the cylinder is fixed on a support. These cathodes are called cages.

Les grilles aussi sont maillées. Elles peuvent être réalisées à partir de nappes de fils d'un matériau réfractaire que l'on croise afin d'obtenir un maillage. On soude les fils entre eux à chaque intersection. L'ensemble ainsi formé a une structure cylindrique et ses extrémités sont raccordées à des supports.The grids are also meshed. They can be made from sheets of son of a refractory material which is crossed in order to obtain a mesh. The wires are welded together at each intersection. The assembly thus formed has a cylindrical structure and its ends are connected to supports.

Une deuxième façon de réaliser une grille est de prendre une feuille de matériau réfractaire, en forme de cylindre, et de la percer d'ouvertures régulièrement espacées afin d'obtenir le maillage.A second way of making a grid is to take a sheet of refractory material, in the shape of a cylinder, and to pierce it with regularly spaced openings in order to obtain the mesh.

Comme matériau réfractaire, on utilise couramment le graphite pyrolitique ou le molybdène. Chaque maille est définie par une succession de barreaux reliés par leurs extrêmités et l'intersection entre deux barreaux est un noeud.As refractory material, pyrolitic graphite or molybdenum is commonly used. Each mesh is defined by a succession of bars connected by their ends and the intersection between two bars is a knot.

La cathode et les grilles, à cause de cette structure très découpée, sont sujettes à des vibrations affectant leur stabilité mécanique. La distance entre la cathode et la grille de commande est faible, généralement inférieure à 1000 micromètre, et les vibrations qui peuvent intervenir entraînent des variations sensibles de cette distance. Ces vibrations sont préjudiciables au bon fonctionnement du tube. Les mêmes remarques s'appliquent aux distances intergrilles dans le cas des tétrodes ou autres tubes multigrilles.The cathode and the grids, because of this very cut structure, are subject to vibrations affecting their mechanical stability. The distance between the cathode and the control grid is small, generally less than 1000 micrometers, and the vibrations which may occur cause appreciable variations in this distance. These vibrations are detrimental to the proper functioning of the tube. The same remarks apply to intergrid distances in the case of tetrodes or other multigrid tubes.

On mesurera l'importance de la stabilité mécanique, en ajoutant que la cathode peut fonctionner à une température de fonctionnement élevée (de l'ordre de 1700 ° C) et qu'elle doit aussi avoir une bonne résistance à la déformation. Les grilles atteindront une température plus faible (de l'ordre de 1200° C) mais devront aussi avoir une bonne résistance à la déformationThe importance of mechanical stability will be measured, adding that the cathode can operate at a high operating temperature (of the order of 1700 ° C.) and that it must also have good resistance to deformation. The grids will reach a lower temperature (around 1200 ° C) but must also have good resistance to deformation

Une autre condition à intégrer, pour obtenir un bon fonctionnement du tube, est la transparence des grilles. Les barreaux et les noeuds des mailles forment une barrière pour les électrons issus de la cathode. L'interception d'un grand nombre d'électrons par une grille, provoque un courant de grille élevé, surtout dans les tubes de grande puissance. Ce courant de grille provoque un échauffement supplémentaire de la grille et nécessite l'utilisation d'une alimentation de grille relativement puissante. La transparence de la grille dépend de sa géométrie.Another condition to integrate, in order to obtain a good functioning of the tube, is the transparency of the grids. The bars and the mesh nodes form a barrier for the electrons coming from the cathode. The interception of a large number of electrons by a grid, causes a high grid current, especially in high power tubes. This grid current causes additional heating of the grid and requires the use of a relatively powerful grid supply. The transparency of the grid depends on its geometry.

Pour réaliser la grille, il faut aussi tenir compte de la répartition du potentiel de grille, entre les barreaux. Il faut que le potentiel soit réparti le plus régulièrement possible. Ceci est important pour la grille de commande qui sert à réguler le potentiel autour de la cathode. Cette dernière condition dépend aussi de la géométrie de la grille.To make the grid, it is also necessary to take into account the distribution of the grid potential between the bars. The potential must be distributed as regularly as possible. This is important for the control grid which is used to regulate the potential around the cathode. This last condition also depends on the geometry of the grid.

Une grille idéale au point de vue potentiel et transparence aurait une infinité de fils verticaux et très fins. Le courant grille serait très faible et le potentiel de grille réparti très régulièrement autour de la cathode.An ideal grid in terms of potential and transparency would have an infinity of vertical and very fine wires. The gate current would be very low and the gate potential distributed very regularly around the cathode.

Cette grille aurait par contre une résistance mécanique extrêmement mauvaise surtout si elle avait de grandes dimensions.However, this grid would have extremely poor mechanical strength, especially if it had large dimensions.

On a donc été amené à croiser les fils pour augmenter la rigidité de la grille.We therefore had to cross the wires to increase the rigidity of the grid.

Les grilles utilisées fréquemment ont des mailles en forme de quadrilatères : carré, rectangle, losange ou parallélogramme. D'un noeud de maille partent quatre barreaux.The grids used frequently have meshes in the form of quadrilaterals: square, rectangle, rhombus or parallelogram. From a knot of mesh leave four bars.

Dans les tubes de grande puissance, une grille de ce type se déforme et l'on a été obligé de la renforcer en rajoutant des barreaux, on a réalisé des mailles triangulaires. De chaque noeud partent maintenant six barreaux. La surface des noeuds est plus importante et le courant grille aussi.In high-power tubes, a grid of this type is deformed and we have been forced to strengthen it by adding bars, we have made triangular meshes. From each node there are now six bars. The surface of the nodes is larger and the current also grows.

La présente invention vise à remédier à ces inconvénients et propose un tube à grille fonctionnant avec un courant de grille réduit. Pour cela on a cherché à minimiser la surface d'interception des électrons, sans nuire ni à la stabilité mécanique, ni à la répartition du potentiel de grille autour de la cathode.The present invention aims to remedy these drawbacks and proposes a grid tube operating with a reduced grid current. To do this, we sought to minimize the interception surface of the electrons, without harming either the mechanical stability or the distribution of the gate potential around the cathode.

La présente invention concerne un tube électronique à électrodes cylindriques concentriques parmi lesquelles une cathode centrale et au moins une grille de type maillé, une maille étant définie par plusieurs barreaux en contact par leurs extrémités, caractérisé en ce que les mailles ont la forme d'hexagone.The present invention relates to an electronic tube with concentric cylindrical electrodes among which a central cathode and at least one grid of the mesh type, a mesh being defined by several bars in contact at their ends, characterized in that the meshes have the shape of a hexagon .

De préférence, les mailles sont sensiblement identiques. De préférence, les hexagones sont sensiblement réguliers. Lorsque cette grille entoure une cathode à fils formant des losanges, l'intersection entre deux fils de cathode est alignée avec la partie centrale d'une maille de grille. De préférence, lorsqu'un barreau de grille recouvre un fil de cathode, le barreau et le fil sont perpendiculaires pour minimiser la surface de recouvrement.Preferably, the meshes are substantially identical. Preferably, the hexagons are substantially regular. When this grid surrounds a cathode with diamonds-forming wires, the intersection between two cathode wires is aligned with the central part of a grid mesh. Preferably, when a grid rod covers a cathode wire, the rod and the wire are perpendicular to minimize the overlap area.

De préférence, les mailles sont réalisées à partir d'une feuille de matériau réfractaire en forme de cylindre percée d'orifices hexagonaux.Preferably, the meshes are produced from a sheet of refractory material in the form of a cylinder pierced with hexagonal orifices.

Le matériau peut être du graphite pyrolitique ou du molybdène.The material can be pyrolitic graphite or molybdenum.

D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description suivante, illustrée par les figures annexées qui représentent :

  • les figures 1a et 1b, un maillage respectivement en parallélogramme et en losange d'une grille d'un tube électronique selon l'art antérieur ;
  • la figure 2, un maillage triangulaire d'une grille d'un tube électronique selon l'art antérieur ;
  • la figure 3, un maillage hexagonal régulier d'une grille d'un tube électronique selon l'invention;
  • la figure 4, un maillage hexagonal irrégulier d'une grille d'un tube électronique selon l'invention;
  • la figure 5, une grille de tube électronique selon l'invention;
  • la figure 6, la superposition d'un maillage de cathode et d'un maillage de grille d'un tube électronique selon l'invention.
Other characteristics and advantages of the invention will appear on reading the following description, illustrated by the appended figures which represent:
  • FIGS. 1a and 1b, a mesh respectively in parallelogram and in rhombus of a grid of an electronic tube according to the prior art;
  • Figure 2, a triangular mesh of a grid of an electronic tube according to the prior art;
  • Figure 3, a regular hexagonal mesh of a grid of an electronic tube according to the invention;
  • FIG. 4, an irregular hexagonal mesh of a grid of an electronic tube according to the invention;
  • FIG. 5, an electron tube grid according to the invention;
  • Figure 6, the superposition of a cathode mesh and a grid mesh of an electronic tube according to the invention.

La figure 1a représente un maillage en parallélogramme d'une grille de tube électronique, de type triode par exemple. La figure 1b représente elle, un maillage en losange.FIG. 1a represents a mesh in parallelogram of an electron tube grid, of the triode type for example. Figure 1b shows it, a diamond mesh.

Chacun de ces maillages peut être réalisé à partir de deux nappes de fils 1,2 sensiblement parallèles, que l'on superpose en les croisant. On soude ensuite les fils 1 d'une nappe sur les fils 2 de l'autre nappe, à tous les points de croisement. On obtient des mailles 4 délimitées par des portions de fils 1, 2 ou barreaux 5. Chaque croisement forme un noeud 3. De chaque noeud 3 partent quatre barreaux 5. Une maille 4 est constituée de quatre barreaux 5.Each of these meshes can be produced from two plies of wires 1,2 which are substantially parallel, which are superimposed by crossing them. The wires 1 of a ply are then welded to the wires 2 of the other ply, at all the crossing points. We obtain meshes 4 delimited by portions of wires 1, 2 or bars 5. Each crossing forms a knot 3. From each node 3 leave four bars 5. A mesh 4 consists of four bars 5.

Sur la figure 1a, une maille 4 a la forme d'un parallélogramme, elle est constituée de quatre barreaux égaux, deux à deux.In FIG. 1a, a mesh 4 has the shape of a parallelogram, it consists of four equal bars, two by two.

Sur la figure 1b, une maille 4 a la forme d'un losange, elle est constituée de quatre barreaux 5 égaux.In Figure 1b, a mesh 4 has the shape of a rhombus, it consists of four equal bars 5.

Les fils 1,2 utilisés pour réaliser ces grilles sont en métal réfractaire, du molybdène par exemple.The wires 1,2 used to make these grids are made of refractory metal, for example molybdenum.

Une grille de ce type peut aussi être confectionnée à partir d'une feuille de matériau réfractaire du graphite ou du molybdène par exemple. La feuille est percée d'ouvertures par tout moyen connu, usinage, sablage ou électoérosion, par exemple. Les ouvertures sont, de préférence, régulièrement espacées et ont une forme appropriée pour obtenir le maillage.A grid of this type can also be made from a sheet of refractory material of graphite or molybdenum for example. The sheet is pierced with openings by any known means, machining, sandblasting or EDM, for example. The openings are preferably regularly spaced and have an appropriate shape to obtain the mesh.

Une grille de tube électronique, par exemple de triode, est cylindrique et elle est montée autour d'une cathode émettant des électrons. Les électrons traversent la grille lorsque cette dernière est portée à un potentiel négatif par rapport à celui de la cathode. Les barreaux 5 et les noeuds 3 forment un écran aux électrons. Certains électrons sont interceptés par la structure de la grille lorsque celle-ci est portée à un potentiel positif par rapport à celui de la cathode. Les électrons interceptés provoquent l'apparition d'un courant de grille. Un courant de grille élevé provoque une augmentation excessive de la température de la grille et nécessite l'utilisation d'une alimentation de grille puissante.An electron tube grid, for example a triode, is cylindrical and it is mounted around a cathode emitting electrons. The electrons pass through the grid when the latter is brought to a negative potential compared to that of the cathode. The bars 5 and the nodes 3 form an electron screen. Certain electrons are intercepted by the structure of the grid when it is brought to a positive potential compared to that of the cathode. The intercepted electrons cause the appearance of a gate current. A high grid current causes an excessive increase in the temperature of the grid and requires the use of a powerful grid supply.

Dans un tube de puissance moyenne, on peut utiliser une grille à maillage tel que représenté sur les figures 1a, 1b. Le courant de grille qui s'établit, à cause de l'interception d'électrons, est acceptable.In a medium power tube, one can use a mesh grid as shown in Figures 1a, 1b. The gate current which is established due to the interception of electrons is acceptable.

Mais lorsque l'on veut réaliser un tube de grande puissance, la grille a alors des dimensions plus importantes et on s'aperçoit qu'elle manque de rigidité.But when we want to make a high power tube, the grid then has larger dimensions and we see that it lacks rigidity.

On a été amené à la renforcer en lui donnant une structure telle que représentée sur la figure 2. On a réalisé un maillage triangulaire. On a utilisé comme précedemment deux nappes de fils croisés 22,23 et on a rajouté, à chaque intersection ou noeud 25 une troisième nappe de fils 21 sensiblement horizontaux. On a réalisé des mailles 24, triangulaires, définies par trois portions de fils 21,22,23 ou barreaux 26, dont les extrémités sont en contact. De chaque noeud 25 partent six barreaux 26.We were led to strengthen it by giving it a structure as shown in Figure 2. We made a triangular mesh. Two plies of crossed wires 22,23 were used as above and a third ply of wires 21 substantially horizontal was added at each intersection or node 25. We made 24 stitches, triangular, defined by three portions of wire 21,22,23 or bars 26, the ends of which are in contact. From each node 25 there are six bars 26.

Avec un tel maillage, on a gagné en stabilité mécanique et en résistance à la déformation. Mais d'autre part, on a augmenté aussi le courant de grille, car on a augmenté la surface d'interception des électrons, notamment au niveau des noeuds 25.With such a mesh, we have gained mechanical stability and resistance to deformation. But on the other hand, the grid current has also been increased, because the interception surface of the electrons has been increased, in particular at the level of the nodes 25.

La figure 3 représente un maillage hexagonal régulier d'une grille de tube électronique selon l'invention. Ce maillage présente des noeuds 36. De chaque noeud 36 partent seulement trois barreaux 35.FIG. 3 represents a regular hexagonal mesh of an electron tube grid according to the invention. This mesh has nodes 36. From each node 36, only three bars 35 leave.

Maintenant chaque maille 34 est hexagonale elle est définie par six barreaux 35 reliés par leurs extrémités.Now each mesh 34 is hexagonal, it is defined by six bars 35 connected by their ends.

On a diminué la surface des noeuds 36 par rapport aux maillages utilisés classiquement. Les électrons interceptés par une grille de ce type, seront moins nombreux et un tube électronique de puissance ayant une grille de ce type, aura un courant grille réduit par rapport au courant grille d'un tube de puissance classique.The surface of the nodes 36 has been reduced compared to the meshes conventionally used. The electrons intercepted by a grid of this type will be fewer and an electronic power tube having a grid of this type will have a reduced grid current compared to the grid current of a conventional power tube.

Le maillage représenté sur la figure 3 est régulier, chaque maille 34 est constituée de barreaux 35 égaux et deux barreaux 35 successifs font un angle de 120°. Toutes les mailles sont sensiblement identiques.The mesh shown in Figure 3 is regular, each mesh 34 is made up of equal bars 35 and two successive bars 35 make an angle of 120 °. All the meshes are substantially identical.

On pourrait envisager que les mailles ne soient pas toutes identiques et que les hexagones soient irréguliers. Un tel maillage est représenté sur la figure 4. On a représenté des grandes mailles 41 en ligne et des plus petites mailles 42 également alignées. Chaque maille 41 ou 42 est un hexagone irrégulier. Les angles entre deux barreaux successifs peuvent être plus grands ou plus petits que 120°.We could consider that the meshes are not all identical and that the hexagons are irregular. Such a mesh is shown in Figure 4. There are shown large meshes 41 in line and smaller meshes 42 also aligned. Each mesh 41 or 42 is an irregular hexagon. The angles between two successive bars can be larger or smaller than 120 °.

La figure 5 est une vue d'une grille maillée de tube électronique selon l'invention. La grille a des mailles 50 hexagonales régulières. Elle a une structure en nid d'abeilles. Elle comporte une partie 51 maillée de forme cylindrique. Les deux extrémités 52 du cylindre sont maintenues chacune sur un support 53.FIG. 5 is a view of a mesh grid of electronic tube according to the invention. The grid has 50 regular hexagonal meshes. It has a honeycomb structure. It comprises a meshed part 51 of cylindrical shape. The two ends 52 of the cylinder are each held on a support 53.

Sur les figures 3,4,5, les mailles hexagonales représentées ont toute la même orientation. Ce n'est qu'un exemple, leur orientation peut être quelconque. Les mailles auraient pu, notamment être tournées de 90°.In Figures 3,4,5, the hexagonal meshes shown have all the same orientation. This is only an example, their orientation can be arbitrary. The meshes could, in particular, have been turned 90 °.

De préférence, la grille sera réalisée à partir d'une feuille de matériau réfractaire, par exemple du graphite pyrolitique, du molybdène, en forme de cylindre. On découpe des orifice. dans cette feuille par tout moyen connu, usinage, sablage, électroérosion, par exemple. On répartit régulierement les orifices sur toute la feuille. On leur donne la forme d'hexagones. On obtient un maillage hexagonal. On fixe chaque extrémité du cylindre sur un support.Preferably, the grid will be produced from a sheet of refractory material, for example pyrolitic graphite, molybdenum, in the form of a cylinder. We cut holes. in this sheet by any known means, machining, sandblasting, EDM, for example. The orifices are distributed regularly over the entire sheet. They are given the shape of hexagons. We obtain a hexagonal mesh. Each end of the cylinder is fixed on a support.

Avec une telle grille, on gagne en stabilité mécanique et en résistance à la déformation par rapport aux grilles à mailles en forme de quadrilatère.With such a grid, one gains in mechanical stability and in resistance to deformation compared to grids with meshes in the form of a quadrilateral.

La surface d'interception a été réduite, au niveau des noeuds, si on la compare à celle des grilles à mailles triangulaires et à mailles en forme de quadrilatère.The interception surface has been reduced, at the level of the nodes, if we compare it to that of the grids with triangular meshes and meshes in the form of a quadrilateral.

La régularité des hexagones et leur orientation sont choisies en fonction des paramètres mécaniques et électriques que doit avoir la grille.The regularity of the hexagons and their orientation are chosen according to the mechanical and electrical parameters that the grid must have.

La géométrie des barreaux, c'est à dire leur longueur et leur section droite, ainsi que l'angle d'intersection entre deux barreaux sont choisis de manière à assurer une transparence aux électrons et un contrôle du potentiel autour de la cathode, correspondant aux caractéristiques que le tube doit avoir.The geometry of the bars, that is to say their length and their cross section, as well as the angle of intersection between two bars are chosen so as to ensure transparency to the electrons and a control of the potential around the cathode, corresponding to the characteristics that the tube must have.

Pour une section de barreaux donnée et une transparence de grille donnée, un maillage hexagonal régulier autorise des mailles plus petites que celles utilisées habituellement. Il en résulte un meilleur contrôle des potentiels entre les barreaux et près de la cathode (si la grille est une grille de commande), une amélioration de la tension de blocage du tube ou "cutt off" ainsi qu'une meilleure répartition des trajectoires des électrons.For a given section of bars and a given grid transparency, a regular hexagonal mesh allows smaller meshes than those usually used. This results in better control of the potentials between the bars and near the cathode (if the grid is a control grid), an improvement in the tube blocking voltage or "cutt off" as well as a better distribution of the electron trajectories.

Pour une section de barreaux donnée et un même contrôle des potentiels entre barreaux et près de la cathode, (s'il s'agit d'une grille de commande), un maillage hexagonal régulier autorise des mailles plus grandes que celles utilisées habituellement. Il en résulte une plus grande transparence de la grille et une diminution du courant de grille notamment en fonctionnement à forte puissance.For a given section of bars and the same control of the potentials between bars and near the cathode ((if it is a control grid), a regular hexagonal mesh allows larger meshes than those usually used. This results in greater transparency of the grid and a reduction in the grid current, in particular in high power operation.

Un autre avantage des grilles à mailles hexagonales régulières apparaît lorsque l'on utilise une cathode en cage. On peut aligner la cathode et la grille. Dans les tubes multigrilles, on alignera la cathode avec la grille de commande et aussi avec les autres grilles.Another advantage of regular hexagonal mesh grids appears when using a cage cathode. You can align the cathode and the grid. In multigrid tubes, the cathode will be aligned with the control grid and also with the other grids.

La figure 6 représente un maillage 60 de cathode en cage recouvert d'un maillage 70 de grille de commande d'un tube électronique selon l'invention. Le maillage 60 de cathode est constitué de deux groupes de fils 61,62 sensiblement parallèles, les deux groupes étant croisés. On a réalisé des mailles 63 en forme de losange.FIG. 6 represents a mesh 60 of a cage cathode covered with a mesh 70 of the control grid of an electronic tube according to the invention. The cathode mesh 60 consists of two groups of wires 61, 62 which are substantially parallel, the two groups being crossed. We made 63 diamond shaped meshes.

Les fils 61,62 de la cathode émettent des électrons lorsqu'ils sont chauffés. Une intersection 64 entre deux fils 61,62 a une surface importante qui émet une forte densité d'électrons.The wires 61, 62 of the cathode emit electrons when they are heated. An intersection 64 between two wires 61, 62 has a large surface which emits a high density of electrons.

Le maillage 70 de grille comporte des mailles 65 hexagonales et régulières constituées de barreaux 66.The grid mesh 70 comprises hexagonal and regular meshes 65 made up of bars 66.

On peut s'arranger pour aligner l'intersection 64 entre deux fils 61,62 de cathode, avec la partie centrale d'une maille 65 de grille. Cette disposition augmente la quantité d'électrons qui passe à travers la grille.We can arrange to align the intersection 64 between two cathode wires 61,62, with the central part of a grid mesh 65. This arrangement increases the amount of electrons that pass through the grid.

Dans le cas de tubes multigrilles, toutes les grilles seront alignées entre elles et seront identiques, de manière à ce que l'intersection 64 entre deux fils 61,62 de cathode soit disposée dans la partie centrale de toutes les mailles de grille.In the case of multigrid tubes, all the grids will be aligned with one another and will be identical, so that the intersection 64 between two cathode wires 61, 62 is placed in the central part of all the grid meshes.

On peut aussi chercher à minimiser les surfaces de fils 61, 62 de cathode recouvertes par un barreau 66 de grille. On s'arrange pour que les barreaux 66 de grille qui recouvrent un fil 61,62 de cathode soient perpendiculaires à ce fil 61,62 de cathode. Par rapport aux structures classiques, pour un même contrôle des potentiels entre barreaux et près de la cathode, on a amélioré la transparence de la grille.We can also try to minimize the areas of cathode wires 61, 62 covered by a grid bar 66. Arrangements are made so that the grid bars 66 which cover a cathode wire 61,62 are perpendicular to this cathode wire 61,62. Compared to conventional structures, for the same control of the potentials between bars and near the cathode, the transparency of the grid has been improved.

L'invention s'applique aussi bien aux grilles de commande qu'aux autres grilles (grille écran, grille d'arrêt... )The invention applies both to control grids and to other grids (screen grid, stop grid ...)

Ce type de maillage hexagonal est particulièrement adapté aux tubes dans lesquels la distance interélectrode est faible car le maillage offre une très bonne stabilité mécanique et une très bonne résistance à la déformation.This type of hexagonal mesh is particularly suitable for tubes in which the interelectrode distance is small because the mesh offers very good mechanical stability and very good resistance to deformation.

Le maillage hexagonal permet de minimiser le courant grille et de bien contrôler le potentiel entre les barreaux.The hexagonal mesh makes it possible to minimize the grid current and to properly control the potential between the bars.

Une grille à mailles hexagonales peut être avantageusement intégrée à un tube de gain élevé et de puissance d'attaque faible.A grid with hexagonal meshes can advantageously be integrated into a tube of high gain and low attack power.

Claims (8)

1 - Tube électronique à électrodes cylindriques concentriques, parmi lesquelles une cathode centrale et au moins une grille de type maillé, une maille ( 34 ) étant définie par plusieurs barreaux (35) en contact par leurs extrêmités caractérisé en ce que les mailles (34) ont la forme d'hexagone. 1 - Electronic tube with concentric cylindrical electrodes, including a central cathode and at least one grid of the mesh type, a mesh (34) being defined by several bars (35) in contact at their ends, characterized in that the meshes (34) have the shape of a hexagon. 2 - Tube électronique selon la revendication 1, caractérisé en ce que les mailles (34) sont sensiblement identiques. 2 - Electronic tube according to claim 1, characterized in that the meshes (34) are substantially identical. 3 - Tube électronique selon l'une des revendications 1 ou 2 caractérisé en ce que les hexagones sont sensiblement réguliers. 3 - Electronic tube according to one of claims 1 or 2 characterized in that the hexagons are substantially regular. 4 - Tube électronique selon la revendication 3, comprenant une cathode à fils (61,62) formant des losanges, caractérisé en ce que l'intersection (64) entre deux fils (61,62) de cathode est alignée avec la partie centrale d'une maille ( 65 ) de grille. 4 - Electronic tube according to claim 3, comprising a cathode son (61,62) forming diamonds, characterized in that the intersection (64) between two son (61,62) of cathode is aligned with the central part d 'a grid mesh (65). 5 - Tube électronique selon la revendication 4, caractérisé en ce que, lorsqu'un barreau (66) de grille recouvre un fil (61,62) de cathode, le barreau (66) de grille et le fil (61,62) de cathode sont perpendiculaires pour minimiser la surface de recouvrement 5 - Electronic tube according to claim 4, characterized in that, when a grid bar (66) covers a cathode wire (61,62), the grid bar (66) and the wire (61,62) of cathode are perpendicular to minimize the overlap area 6 - Tube électronique selon l'une des revendications 1 à 5 caractérisé en ce que les mailles (34) sont réalisées par des ouvertures percées dans une feuille en forme de cylindre, d'un matériau réfractaire. 6 - Electronic tube according to one of claims 1 to 5 characterized in that the meshes (34) are made by openings drilled in a sheet in the form of a cylinder, of a refractory material. 7 - Tube électronique selon la revendication 6, caractérisé en ce que le matériau est du graphite pyrolitique. 7 - Electronic tube according to claim 6, characterized in that the material is pyrolitic graphite. 8 - Tube électronique selon la revendication 6 caractérisé en ce que le matériau est du molybdène. 8 - Electronic tube according to claim 6 characterized in that the material is molybdenum.
EP91401116A 1990-05-11 1991-04-26 Electron tube with cylindrical grid Expired - Lifetime EP0456550B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9005903 1990-05-11
FR9005903A FR2662020B1 (en) 1990-05-11 1990-05-11 ELECTRONIC TUBE WITH CYLINDRICAL GRID.

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EP0456550A1 true EP0456550A1 (en) 1991-11-13
EP0456550B1 EP0456550B1 (en) 1996-05-22

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US7049614B2 (en) * 2003-03-10 2006-05-23 Intel Corporation Electrode in a discharge produced plasma extreme ultraviolet source
AU2006311827A1 (en) * 2005-11-03 2007-05-18 Redpoint Bio Corporation High throughput screening assay for the TRPM5 ion channel
WO2007134432A1 (en) 2006-05-18 2007-11-29 Valerian Pershin Highly ordered structure pyrolitic graphite or carbon-carbon composite cathodes for plasma generation in carbon containing gases
US20170284567A1 (en) * 2016-03-30 2017-10-05 The Boeing Company Grommet, conduit support assembly, and method of supporting a conduit

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US4546286A (en) * 1982-07-27 1985-10-08 Bbc Brown, Boveri & Company, Limited Electron tube, in particular a transmitter tube

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US4546286A (en) * 1982-07-27 1985-10-08 Bbc Brown, Boveri & Company, Limited Electron tube, in particular a transmitter tube

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FR2662020B1 (en) 1996-04-19
DE69119645D1 (en) 1996-06-27
FR2662020A1 (en) 1991-11-15
EP0456550B1 (en) 1996-05-22
US5225735A (en) 1993-07-06

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