EP0052047A1 - Thermoelectronic cathode - Google Patents

Thermoelectronic cathode Download PDF

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Publication number
EP0052047A1
EP0052047A1 EP81401713A EP81401713A EP0052047A1 EP 0052047 A1 EP0052047 A1 EP 0052047A1 EP 81401713 A EP81401713 A EP 81401713A EP 81401713 A EP81401713 A EP 81401713A EP 0052047 A1 EP0052047 A1 EP 0052047A1
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EP
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Prior art keywords
cathode according
tungsten
impregnated
thermoelectronic
barium
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EP81401713A
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German (de)
French (fr)
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EP0052047B1 (en
EP0052047B2 (en
Inventor
Pierre Palluel
Arvind Shroff
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Thales SA
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Thomson CSF SA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
    • H01J1/28—Dispenser-type cathodes, e.g. L-cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/02—Electrodes; Magnetic control means; Screens
    • H01J23/04—Cathodes

Definitions

  • the present invention relates to a new thermoelectronic cathode structure.
  • Such cathodes find their field of application in electronic tubes, tubes with localized constants such as triodes and tetrodes, or tubes with distributed constants such as klystrons and magnetrons used at microwave frequencies.
  • the invention also relates to such electronic tubes.
  • the power developed by electronic tubes at very high frequencies is limited in particular by the current density produced by the cathode.
  • Thermoelectronic cathodes with a reserve of emissive material have long been known, known as "L" cathodes;
  • Another improvement consisted in replacing the reserve of alkaline earth with a ceramic consisting of a mixture of aluminum, mine, alkaline earth oxides and tungsten powder.
  • L type cathodes have always had a density of emitted current, at equal temperature, greater than that of so-called impregnated cathodes, even in the best cases when the latter are covered with '' a film of a refractory metal with high output work like osmium, ruthenium, iridium, rhenium, which tends to increase the current density.
  • the Applicant proposes to produce a cathode structure whose current density is at least equal to that of "L" cathodes, but which would not present the difficulties of technological realization of the latter.
  • the cathode structure according to the invention consists of two superposed porous bodies of identical or different porosity, the lower porous body being impregnated with barium and calcium aluminates for example, the upper porous body not being impregnated, the together being brazed in a molybdenum skirt to ensure the mechanical and thermal solidarity of the two porous bodies as well as the establishment of a heating filament.
  • thermoelectronic cathode comprising inside a cylindrical envelope, in molybdenum for example, a heating filament located in the lower part of said envelope, and above, a chamber filled with a certain quantity of material.
  • porous, cathode characterized in that said chamber comprises two separate superimposed parts, namely a part made of a porous material impregnated with emissive material covered with a part made of a porous material not impregnated.
  • FIG. 1 shows an example of a cathode structure "L" of the prior art.
  • a cathode is constituted by a molybdenum tube 1, divided into two cavities; the lower part contains the heating filament, 2; the upper part consists of a chamber 3 containing a reserve of 4 barium and calcium carbonates for example.
  • a porous tungsten disc 5 is attached to the top of the barium reservoir, so that the upper cavity communicates outward only through the porous body.
  • the upper face of this disc may comprise a thin layer 6 of a refractory metal with high output work such as osmium, iridium, rhenium, ruthenium, or an alloy of several of these materials.
  • a refractory metal with high output work such as osmium, iridium, rhenium, ruthenium, or an alloy of several of these materials.
  • FIG. 2 represents an example of a cathode structure impregnated with the prior art.
  • a filament 2 is located inside a molybdenum cylinder 1 containing a body of porous tungsten 7 which is impregnated with barium and calcium aluminates.
  • the upper face of the body 7 can be covered with a thin layer 6 of a refractory metal with high output work from one of those mentioned above.
  • the underside of the coprs 7 rests on a molybdenum bottom 8 ensuring sealing.
  • FIG. 3 represents an example of a cathode structure according to the invention.
  • the cathode according to the invention consists of a cylindrical molybdenum body 1 inside which is located a filament 2 in its lower part and a set of two porous bodies superimposed in its upper part: a porous body 9 free of all impregnating, with a porosity of between 16 and 21%, made of tungsten or of a tungsten alloy and of a refractory metal with high output work such as iridium, rhenium, osmium, ruthenium, porous body whose front face 10 is the only one by which the emissive material can be evacuated; It is possible to cover the front face 10 with a layer 15 obtained by depositing oriented tungsten by vapor phase for example, revealing a relief of successive islands on which an anti-emissive coating 16 is deposited of a material with high output work.
  • a porous body 12 impregnated with barium aluminates and calcium or a mixture comprising barium aluminates, calcium and a scandium oxide or "barium scandate", porous body having a porosity of between 16 and 50%, for example; the rear face of this body is made waterproof by conventional means such as the deposition of molybdenum-ruthenium solder, or by resting on a molybdenum base 13.
  • a gap or gap 14 which is filled, in order to improve the thermal contact before the porous body 9 ′ is put in place, either of powder of a conductive metal at high melting temperature, either a molybdenum grid or tungsten, with a very fine mesh, of pitch 20 ⁇ m for example, which serves as additional conductance for the diffusion of barium towards the porous body 9, either with a flexible foil ensuring contact between the cathode bodies, or using threading.
  • This gap 14 can be eliminated by producing the assembly by pressing and impregnating the porous body 12 only, or by impregnating the assembly and eliminating by chemical attack the excess of impregnator contained in the porous body 9.
  • the porous body 9 generally has a curved shape obtained by machining or by pressing.
  • the operating mechanism of this type of cathode is as follows: the free barium is produced in the porous body 12 by heating the assembly using the filament 2, by chemical reaction between the impregnant and the tungsten.
  • This barium then migrates through the pores of the body 9 from the face 11 to the face 10 where it comes to cover its surface, thus lowering the work of leaving it.
  • An electrode placed opposite the cathode, at a certain distance, and brought to a positive potential with respect to the cathode, collects the electrons emitted by the latter.

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  • Solid Thermionic Cathode (AREA)
  • Microwave Tubes (AREA)

Abstract

Une telle cathode comporte un corps cylindrique en molybdène (1) entourant un filament chauffant (2) et au-dessus du filament une superposition de deux corps poreux, l'un (12) étant imprégné, l'autre (9) recouvrant ce dernier n'étant pas imprégné.Such a cathode comprises a cylindrical molybdenum body (1) surrounding a heating filament (2) and above the filament a superposition of two porous bodies, one (12) being impregnated, the other (9) covering the latter not being impregnated.

Description

La présente invention concerne une nouvelle structure de cathode thermoélectronique. De telles cathodes trouvent leur domaine d'application dans les tubes électroniques, tubes à constantes localisées comme les triodes et les tétrodes, ou tubes à constantes réparties comme les klystrons et les magnétrons utilisés en hyperfréquences.The present invention relates to a new thermoelectronic cathode structure. Such cathodes find their field of application in electronic tubes, tubes with localized constants such as triodes and tetrodes, or tubes with distributed constants such as klystrons and magnetrons used at microwave frequencies.

L'invention concerne également de tels tubes électroniques.The invention also relates to such electronic tubes.

La puissance développée par les tubes électroniques à des hyperfréquences très élevées est limitée notamment par la densité de courant produite par la cathode.The power developed by electronic tubes at very high frequencies is limited in particular by the current density produced by the cathode.

Il existe depuis longtemps des cathodes thermo-électronique à réserve de matière émissive connues sous le nom de cathodes "L" ;Thermoelectronic cathodes with a reserve of emissive material have long been known, known as "L" cathodes;

Elles sont constituées par un tube en molybdène divisé en deux cavités ; la partie inférieure contient l'élément chauffant ; la partie supérieure comporte un mélange de carbonate de baryum et de calcium, par exemple, et fonctionne comme un réservoir de baryum un disque de tungstène poreux est fixé au sommet du réservoir de baryum, de sorte que la cavité supérieure ne communique vers l'extérieur qu'à travers le corps poreux. Le défaut de ce système est qu'il faut transformer les carbonates en oxydes, opération longue à cause des gaz de réactions qui ne peuvent s'échapper qu'à travers le tungstène poreux.They consist of a molybdenum tube divided into two cavities; the lower part contains the heating element; the upper part contains a mixture of barium carbonate and calcium, for example, and functions as a barium tank a porous tungsten disc is fixed to the top of the barium tank, so that the upper cavity does not communicate towards the outside only through the porous body. The drawback of this system is that it is necessary to transform the carbonates into oxides, a long operation because of the reaction gases which can only escape through porous tungsten.

Une amélioration du présent état de fait a été apportée par l'utilisation directe d'oxydes d'alcalino-terreux et non plus de carbonates ; cependant, cette amélioration a amené une autre difficulté importante, celle de la réalisation pratique et du stockage de telles cathodes, du fait de la grande réactivité des oxydes alcalino-terreux avec l'air ambiant.An improvement in the present state of affairs has been brought about by the direct use of alkaline earth oxides and no longer of carbonates; however, this improvement has brought another important difficulty, that of the practical production and storage of such cathodes, due to the high reactivity of the alkaline earth oxides with ambient air.

Une autre amélioration a consisté à remplacer la réserve d'alcalino-terreux par une céramique constitué d'un mélange d'alu- , mine, d'oxydes alcalino-terreux et de poudre de tungstène.Another improvement consisted in replacing the reserve of alkaline earth with a ceramic consisting of a mixture of aluminum, mine, alkaline earth oxides and tungsten powder.

Les problèmes technologiques des cathodes à réserve ont conduit l'homme de l'art à utiliser dans la pratique les cathodes dites imprégnées constituées par une matrice en tungstène imprégnée d'aluminates de baryum et de calcium, dans des proportions variables.The technological problems of reserve cathodes have led those skilled in the art to use in practice so-called impregnated cathodes constituted by a tungsten matrix impregnated with barium and calcium aluminates, in variable proportions.

Cependant, d'après les résultats connus actuellement, les cathodes de type "L" ont toujours présenté une densité de courant émis, à température égale, supérieure à celle des cathodes dites imprégnées, même dans les meilleurs des cas quand ces dernières sont recouvertes d'un film d'un métal réfractaire à haut travail de sortie comme l'osmium, le ruthénium, l'iridium, le rhénium, ce qui tend à augmenter la densité de courant.However, according to the results currently known, "L" type cathodes have always had a density of emitted current, at equal temperature, greater than that of so-called impregnated cathodes, even in the best cases when the latter are covered with '' a film of a refractory metal with high output work like osmium, ruthenium, iridium, rhenium, which tends to increase the current density.

Partant de ces constatations, la Demanderesse se propose de réaliser une structure de cathode dont la densité de courant est au moins égale à celle des cathodes "L", mais qui ne présenterait pas les difficultés de réalisation technologique de ces dernières.Based on these observations, the Applicant proposes to produce a cathode structure whose current density is at least equal to that of "L" cathodes, but which would not present the difficulties of technological realization of the latter.

La structure de cathode selon l'invention est constituée par deux corps poreux superposés de porosité identique ou différente, le corps poreux inférieur étant imprégné d'aluminates de baryum et de calcium par exemple, le corps poreux supérieur n'étant pas imprégné, l'ensemble étant brasé dans une jupe en molybdène permettant d'assurer la solidarité mécanique et thermique des deux corps poreux ainsi que la mise en place d'un filament de chauffage.The cathode structure according to the invention consists of two superposed porous bodies of identical or different porosity, the lower porous body being impregnated with barium and calcium aluminates for example, the upper porous body not being impregnated, the together being brazed in a molybdenum skirt to ensure the mechanical and thermal solidarity of the two porous bodies as well as the establishment of a heating filament.

Les avantages d'une telle cathode par rapport aux cathodes connues dans l'art antérieur sont :

  • - sa réalisation technologique non complexe ne nécessitant pas d'appareillage compliqué tel que machine de transfert évitant la mise à l'air des oxydes.
  • - son stockage en atmosphère neutre, les aluminates ne nécessisant pas de précautions excessives.
  • - en fonctionnement, une évaporation non excessive au début de la durée de vie du fait que la zone où le baryum est créée est éloignée de la surface, et que le chemin à franchir par le baryum est toujours le même ; cette vitesse d'évaporation se maintient dans le temps du fait de la constance de cette distance
  • - l'émission électronique qui résulte du recouvrement en baryum est équivalente sinon supérieure à celle des cathodes imprégnées utilisant un matériau poreux analogue.
The advantages of such a cathode compared to cathodes known in the prior art are:
  • - Its non-complex technological implementation does not require complicated equipment such as a transfer machine avoiding the venting of oxides.
  • - its storage in a neutral atmosphere, the aluminates not requiring excessive precautions.
  • - in operation, non-excessive evaporation at the start of the service life because the area where the barium is created is far from the surface, and the path to be crossed by the barium is always the same; this rate of evaporation is maintained in the time due to the constancy of this distance
  • - The electronic emission which results from the barium covering is equivalent if not greater than that of impregnated cathodes using a similar porous material.

La présente invention concerne une cathode thermo-électronique comprenant à l'intérieur d'une enveloppe cylindrique, en molybdène par exemple, un filament chauffant situé dans la partie inférieure de ladite enveloppe, et supérieurement, une chambre remplie d'une certaine quantité de matériau poreux, cathode caractérisée en ce que ladite chambre comprend deux parties distinctes superposées, à savoir une partie en un matériau poreux imprégné de matière émissive recouverte d'une partie en un matériau poreux non imprégné.The present invention relates to a thermoelectronic cathode comprising inside a cylindrical envelope, in molybdenum for example, a heating filament located in the lower part of said envelope, and above, a chamber filled with a certain quantity of material. porous, cathode characterized in that said chamber comprises two separate superimposed parts, namely a part made of a porous material impregnated with emissive material covered with a part made of a porous material not impregnated.

L'invention sera mieux comprise en se reportant à la description suivante illustrée par les figures jointes qui représentent :

  • - Figure 1 : un exemple de cathode "L" de l'art antérieur.
  • - Figure 2 : un exemple de cathode imprégnée de l'art antérieur.
  • - Figure 3 : un exemple de cathode selon l'invention.
The invention will be better understood by referring to the following description illustrated by the attached figures which represent:
  • - Figure 1: an example of cathode "L" of the prior art.
  • - Figure 2: an example of cathode impregnated with the prior art.
  • - Figure 3: an example of a cathode according to the invention.

La figure 1 représente un exemple de structure de cathode "L" de l'art antérieur. Une telle cathode est constituée par un tube en molybdène 1, divisé en deux cavités ; la partie inférieure contient le filament chauffant, 2 ; la partie supérieure est constituée d'une chambre 3 contenant une réserve 4 carbonates de baryum et de calcium par exemple.FIG. 1 shows an example of a cathode structure "L" of the prior art. Such a cathode is constituted by a molybdenum tube 1, divided into two cavities; the lower part contains the heating filament, 2; the upper part consists of a chamber 3 containing a reserve of 4 barium and calcium carbonates for example.

Un disque de tungstène poreux 5 est fixé au sommet du réservoir de baryum, de sorte que la cavité supérieure ne communique vers l'extérieur qu'à travers le corps poreux.A porous tungsten disc 5 is attached to the top of the barium reservoir, so that the upper cavity communicates outward only through the porous body.

La face supérieure de ce disque peut comporter une mince couche 6 d'un métal réfractaire à haut travail de sortie tel l'osmium, l'iridium, le rhénium, le ruthénium, ou un alliage de plusieurs de ces matériaux.The upper face of this disc may comprise a thin layer 6 of a refractory metal with high output work such as osmium, iridium, rhenium, ruthenium, or an alloy of several of these materials.

Le défaut de ce système est qu'il faut transformer les carbonates en oxydes, opération longue à cause de gaz de réactions qui ne peuvent s'échapper qu'à travers le tungstène poreux.The drawback of this system is that it is necessary to transform the carbonates into oxides, a long operation because of reaction gases which can only escape through porous tungsten.

La figure 2 représente un exemple de structure de cathode imprégnée de l'art antérieur. Sur la figure 2, un filament 2 se trouve à l'intérieur d'un cylindre en molybdène 1 contenant un corps en tungstène poreux 7 qui est imprégné d'aluminates de baryum et de calcium. La face supérieure du corps 7 peut être recouverte d'une mince couche 6 d'un métal réfractaire à haut travail de sortie parmi l'un de ceux cités précédemment. La face inférieure du coprs 7 repose sur un fond en molybdène 8 assurant l'étanchéité.FIG. 2 represents an example of a cathode structure impregnated with the prior art. In FIG. 2, a filament 2 is located inside a molybdenum cylinder 1 containing a body of porous tungsten 7 which is impregnated with barium and calcium aluminates. The upper face of the body 7 can be covered with a thin layer 6 of a refractory metal with high output work from one of those mentioned above. The underside of the coprs 7 rests on a molybdenum bottom 8 ensuring sealing.

La figure 3 représente un exemple de structure de cathode selon l'invention.FIG. 3 represents an example of a cathode structure according to the invention.

La cathode selon l'invention est constituée d'un corps cylindrique en molybdène 1 à l'intérieur duquel est situé un filament 2 dans sa partie inférieure et un ensemble de deux corps poreux superposés dans sa partie supérieure : un corps poreux 9 libre de tout imprégnant, de porosité comprise entre 16 et 21%, en tungstène ou en alliage de tungstène et d'un métal réfractaire à haut travail de sortie tels l'iridium, le rhénium, l'osmium, le ruthénium, corps poreux dont la face avant 10 est la seule par laquelle la matière émissive peut s'évacuer ; Il est possible de recouvrir la face avant 10 d'une couche 15 obtenue en déposant par phase vapeur du tungstène orienté par exemple, laissant apparaître un relief d'îlots successifs sur lesquels on dépose un revêtement anti-émissif 16 d'un matériau à haut travail de sortie. Sa face arrière 11 est placée vis à vis d'un corps poreux 12 imprégné d'aluminates de baryum et de calcium ou d'un mélange comprenant des aluminates de baryum, de calcium et un oxyde de scandium ou "de scandate de baryum, ce corps poreux ayant une porosité comprise entre 16 et 50%, par exemple ; la face arrière de ce corps est rendue étanche par les moyens classiques tels que le dépôt de brasure Molybdène-Ruthénium, ou en reposant sur un fond en molybdène 13.The cathode according to the invention consists of a cylindrical molybdenum body 1 inside which is located a filament 2 in its lower part and a set of two porous bodies superimposed in its upper part: a porous body 9 free of all impregnating, with a porosity of between 16 and 21%, made of tungsten or of a tungsten alloy and of a refractory metal with high output work such as iridium, rhenium, osmium, ruthenium, porous body whose front face 10 is the only one by which the emissive material can be evacuated; It is possible to cover the front face 10 with a layer 15 obtained by depositing oriented tungsten by vapor phase for example, revealing a relief of successive islands on which an anti-emissive coating 16 is deposited of a material with high output work. Its rear face 11 is placed opposite a porous body 12 impregnated with barium aluminates and calcium or a mixture comprising barium aluminates, calcium and a scandium oxide or "barium scandate", porous body having a porosity of between 16 and 50%, for example; the rear face of this body is made waterproof by conventional means such as the deposition of molybdenum-ruthenium solder, or by resting on a molybdenum base 13.

Il existe entre les corps poreux 9 et 12 un intervalle ou gap 14, qui est rempli, afin d'améliorer le contact thermique avant mise en place du corps poreux 9', soit de poudre d'un métal conducteur à température de fusion élevée, soit d'une grille en molybdène ou en tungstène, à maille très fine, de pas 20 um par exemple, qui sert de conductance supplémentaire à la diffusion du baryum vers le corps poreux 9, soit d'un clinquant souple assurant un contact entre les corps de cathodes, soit à l'aide d'un filtage. Ce gap 14 peut être supprimé en réalisant l'ensemble par pressage et en imprégnant le corps poreux 12 uniquement, ou en imprégnant l'ensemble et en éliminant par attaque chimique l'excédent d'imprégnant contenu dans le corps poreux 9.There exists between the porous bodies 9 and 12 a gap or gap 14, which is filled, in order to improve the thermal contact before the porous body 9 ′ is put in place, either of powder of a conductive metal at high melting temperature, either a molybdenum grid or tungsten, with a very fine mesh, of pitch 20 μm for example, which serves as additional conductance for the diffusion of barium towards the porous body 9, either with a flexible foil ensuring contact between the cathode bodies, or using threading. This gap 14 can be eliminated by producing the assembly by pressing and impregnating the porous body 12 only, or by impregnating the assembly and eliminating by chemical attack the excess of impregnator contained in the porous body 9.

Le corps poreux 9 a généralement une forme galbée obtenue par usinage ou par pressage.The porous body 9 generally has a curved shape obtained by machining or by pressing.

D'autres formes de réalisation sont possibles comme l'utilisation dans un magnétron ou un girotron.Other embodiments are possible such as use in a magnetron or a girotron.

Le mécanisme de fonctionnement de ce type de cathode est le suivant : le baryum libre, est produit dans le corps poreux 12 par chauffage de l'ensemble à l'aide du filament 2, par réaction chimique entre l'imprégnant et le tungstène.The operating mechanism of this type of cathode is as follows: the free barium is produced in the porous body 12 by heating the assembly using the filament 2, by chemical reaction between the impregnant and the tungsten.

Ce baryum migre ensuite à travers les pores du corps 9 depuis la face 11 jusqu'à la face 10 où il vient recouvrir sa surface, abaissant ainsi le travail de sortie de celle-ci.This barium then migrates through the pores of the body 9 from the face 11 to the face 10 where it comes to cover its surface, thus lowering the work of leaving it.

Une électrode, non représentée sur la figure 3, placée vis à vis de la cathode, à une certaine distance, et portée à un potentiel positif par rapport à la cathode, recueille les électrons émis par cette dernière.An electrode, not shown in FIG. 3, placed opposite the cathode, at a certain distance, and brought to a positive potential with respect to the cathode, collects the electrons emitted by the latter.

Claims (12)

1. Cathode thermo-électronique comprenant à l'intérieur d'une enveloppe cylindrique (1), en molybdène par exemple, un filament chauffant (2) situé dans la partie inférieure de ladite enveloppe, et supérieurement, une chambre remplie d'une certaine quantité de matériau poreux, caractérisée en ce que ladite chambre comprend deux parties distinctes superposées à savoir une partie (12) en un matériau poreux imprégné de matière émissive recouverte d'une partie (9) en un matériau poreux non imprégné.1. Thermo-electronic cathode comprising inside a cylindrical envelope (1), in molybdenum for example, a heating filament (2) located in the lower part of said envelope, and above, a chamber filled with a certain quantity of porous material, characterized in that said chamber comprises two separate superimposed parts, namely a part (12) made of a porous material impregnated with emissive material covered with a part (9) made of a porous material not impregnated. 2. Cathode thermo-électronique suivant la revendication 1, caractérisée en ce que le matériau (9) a une porosité comprise entre 16% et 21%.2. Thermoelectronic cathode according to claim 1, characterized in that the material (9) has a porosity of between 16% and 21%. 3. Cathode thermo-électronique suivant la revendication 1, caractérisée en ce que le matériau (12) a un porosité comprise entre 16% et 50%.3. Thermoelectronic cathode according to claim 1, characterized in that the material (12) has a porosity of between 16% and 50%. 4. Cathode thermo-électronique suivant la revendication 1, caractérisée en ce que le matériau (9) est du tungstène.4. Thermoelectronic cathode according to claim 1, characterized in that the material (9) is tungsten. 5. Cathode thermo-électronique suivant la revendication 1, caractérisée en ce que le matériau (9) est un alliage de tungstène et d'un métal à haut travail de sortie.5. Thermoelectronic cathode according to claim 1, characterized in that the material (9) is an alloy of tungsten and a metal with high output work. 6. Cathode thermo-électronique suivant la revendication 5, caractérisé en ce que ledit métal à haut travail de sortie est de l'iridium.6. Thermoelectronic cathode according to claim 5, characterized in that said metal with high output work is iridium. 7. Cathode thermo-électronique suivant les revendications 4 ou 5 caractérisée en ce que le matériau (9) est recouvert d'une couche d'un métal réfractaire à haut travail de sortie.7. Thermoelectronic cathode according to claims 4 or 5 characterized in that the material (9) is covered with a layer of a refractory metal with high output work. 8. Cathode thermo-électrique suivant les revendications 4 ou 5, caractérisé en ce que le matériau (9) est recouvert d'une couche de tungstène (15) présentant des parties en creux et des parties en relief, lesdites parties en relief étant elles-mêmes recouvertes d'un matériau réfractaire à haut travail de sortie (16).8. Thermoelectric cathode according to claims 4 or 5, characterized in that the material (9) is covered with a layer of tungsten (15) having hollow parts and raised parts, said raised parts being - even covered with a refractory material with high output work (16). 9. Cathode thermo-électronique suivant la revendication 1, caractérisée en ce que le matériau (12) est du tungstène imprégné d'aluminates de baryum et de calcium.9. Thermoelectronic cathode according to claim 1, characterized in that the material (12) is tungsten impregnated with barium aluminates and calcium. 10. Cathode thermo-électronique suivant la revendication 1, caractérisée en ce que le matériau (12) est un alliage de tungstène et d'un métal réfractaire à haut travail de sortie, imprégné d'aluminates de baryum et de calcium.10. Thermoelectronic cathode according to claim 1, characterized in that the material (12) is an alloy of tungsten and of a refractory metal with high output work, impregnated with barium and calcium aluminates. 11. Cathode thermo-électronique suivant la revendication 1, caractérisée en ce que le matériau (12) est du tungstène imprégné d'un mélange d'aluminates de baryum et de calcium, et d'un oxyde de scandium.11. Thermoelectronic cathode according to claim 1, characterized in that the material (12) is tungsten impregnated with a mixture of barium aluminates and calcium, and a scandium oxide. 12. Tube électronique pour hyperfréquence caractérisé en ce qu'il comporte une cathode selon l'une des revendications 1 à 11.12. Electronic tube for microwave characterized in that it comprises a cathode according to one of claims 1 to 11.
EP81401713A 1980-11-07 1981-10-27 Thermoelectronic cathode Expired - Lifetime EP0052047B2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8023884 1980-11-07
FR8023884A FR2494035A1 (en) 1980-11-07 1980-11-07 THERMO-ELECTRONIC CATHODE FOR MICROFREQUENCY TUBE AND TUBE INCORPORATING SUCH A CATHODE

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EP0052047A1 true EP0052047A1 (en) 1982-05-19
EP0052047B1 EP0052047B1 (en) 1986-01-08
EP0052047B2 EP0052047B2 (en) 1990-05-02

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EP (1) EP0052047B2 (en)
JP (1) JPS57107534A (en)
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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2596198A1 (en) * 1986-03-19 1987-09-25 Thomson Csf Cathodes for multibeam klystron, klystron containing such cathodes and method of manufacturing such cathodes
EP0282040A1 (en) * 1987-03-10 1988-09-14 Siemens Aktiengesellschaft Dispenser cathode, especially metal capillary cathode, for electric discharge vessels
EP0401068A1 (en) * 1989-05-30 1990-12-05 Thomson Tubes Electroniques Impregnated thermionic cathode for electron tube
FR2651369A1 (en) * 1989-08-22 1991-03-01 Asea Brown Boveri QUASI OPTICAL GYROTRON.
EP0757370A1 (en) * 1995-07-31 1997-02-05 Philips Patentverwaltung GmbH Electric discharge tube or discharge lamp and scandate dispenser cathode
EP0890972A1 (en) * 1997-07-09 1999-01-13 Matsushita Electronics Corporation Impregnated cathode and method for manufacturing the same
US6351061B1 (en) 1997-09-26 2002-02-26 Matsushita Electric Industrial Co., Ltd. Cathode, method for manufacturing the cathode, and picture tube

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0719530B2 (en) * 1984-06-29 1995-03-06 株式会社日立製作所 Cathode ray tube
JPH0416344Y2 (en) * 1985-07-02 1992-04-13
US4810926A (en) * 1987-07-13 1989-03-07 Syracuse University Impregnated thermionic cathode
US5266414A (en) * 1988-03-18 1993-11-30 Varian Associates, Inc. Solid solution matrix cathode
US6495949B1 (en) * 1999-11-03 2002-12-17 Orion Electric Co., Ltd. Electron tube cathode
FR2833406A1 (en) * 2001-12-10 2003-06-13 Thomson Licensing Sa VACUUM TUBE CATHODE WITH IMPROVED LIFETIME
CN103311066B (en) * 2013-06-03 2015-08-19 哈尔滨工业大学 There is the emitter of the hollow cathode of controlling oneself for spacecraft of inner core

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1093241A (en) * 1953-02-16 1955-05-02
FR1124860A (en) * 1954-06-29 1956-10-19 Siemens Ag Indirectly heated cathode for electric discharge tube
FR2069601A5 (en) * 1969-11-21 1971-09-03 Philips Nv
US3719856A (en) * 1971-05-19 1973-03-06 O Koppius Impregnants for dispenser cathodes
FR2356263A1 (en) * 1976-06-21 1978-01-20 Varian Associates IRIDIUM CATHODE FOR HYPERFREQUENCY TUBE
FR2390825A1 (en) * 1977-05-13 1978-12-08 Thomson Csf THERMO-IONIC CATHODE WITH INCORPORATED GRID, ITS MANUFACTURING PROCESS AND ELECTRONIC TUBE INCLUDING SUCH A CATHODE
DE2808134A1 (en) * 1978-02-25 1979-08-30 Licentia Gmbh Long-life cathode with porous two layer emitter - has emitting layer thinner and of lower porosity than supporting layer
GB2060246A (en) * 1979-10-01 1981-04-29 Hitachi Ltd Impregnated cathode

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL94233C (en) * 1954-12-06
US3076915A (en) * 1954-12-24 1963-02-05 Egyesuelt Izzolampa Cathode assembly and method of making same
NL272981A (en) * 1961-01-02
US3373307A (en) * 1963-11-21 1968-03-12 Philips Corp Dispenser cathode
US3558966A (en) * 1967-03-01 1971-01-26 Semicon Associates Inc Directly heated dispenser cathode
US3842309A (en) * 1970-11-12 1974-10-15 Philips Corp Method of manufacturing a storage cathode and cathode manufactured by said method
DE2245717A1 (en) * 1972-09-18 1974-03-28 Patra Patent Treuhand ELECTRODE WITH A POROUS SINTER BODY
US4310603A (en) * 1978-11-30 1982-01-12 Varian Associates, Inc. Dispenser cathode

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1093241A (en) * 1953-02-16 1955-05-02
FR1124860A (en) * 1954-06-29 1956-10-19 Siemens Ag Indirectly heated cathode for electric discharge tube
FR2069601A5 (en) * 1969-11-21 1971-09-03 Philips Nv
US3719856A (en) * 1971-05-19 1973-03-06 O Koppius Impregnants for dispenser cathodes
FR2356263A1 (en) * 1976-06-21 1978-01-20 Varian Associates IRIDIUM CATHODE FOR HYPERFREQUENCY TUBE
FR2390825A1 (en) * 1977-05-13 1978-12-08 Thomson Csf THERMO-IONIC CATHODE WITH INCORPORATED GRID, ITS MANUFACTURING PROCESS AND ELECTRONIC TUBE INCLUDING SUCH A CATHODE
DE2808134A1 (en) * 1978-02-25 1979-08-30 Licentia Gmbh Long-life cathode with porous two layer emitter - has emitting layer thinner and of lower porosity than supporting layer
GB2060246A (en) * 1979-10-01 1981-04-29 Hitachi Ltd Impregnated cathode

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2596198A1 (en) * 1986-03-19 1987-09-25 Thomson Csf Cathodes for multibeam klystron, klystron containing such cathodes and method of manufacturing such cathodes
EP0282040A1 (en) * 1987-03-10 1988-09-14 Siemens Aktiengesellschaft Dispenser cathode, especially metal capillary cathode, for electric discharge vessels
EP0401068A1 (en) * 1989-05-30 1990-12-05 Thomson Tubes Electroniques Impregnated thermionic cathode for electron tube
FR2647952A1 (en) * 1989-05-30 1990-12-07 Thomson Tubes Electroniques IMPREGNATED THERMOELECTRONIC CATHODE FOR ELECTRONIC TUBE
US5134343A (en) * 1989-08-22 1992-07-28 Asea Brown Boveri Ltd. Quasi-optical gyrotron having an electron gun with alternating high and low density electron emitting segments
CH678671A5 (en) * 1989-08-22 1991-10-15 Asea Brown Boveri
FR2651369A1 (en) * 1989-08-22 1991-03-01 Asea Brown Boveri QUASI OPTICAL GYROTRON.
EP0757370A1 (en) * 1995-07-31 1997-02-05 Philips Patentverwaltung GmbH Electric discharge tube or discharge lamp and scandate dispenser cathode
EP0890972A1 (en) * 1997-07-09 1999-01-13 Matsushita Electronics Corporation Impregnated cathode and method for manufacturing the same
US6306003B1 (en) 1997-07-09 2001-10-23 Matsushita Electric Industrial Co., Ltd. Impregnated cathode and method for manufacturing the same
US6376975B1 (en) 1997-07-09 2002-04-23 Matsushita Electric Industrial Co., Ltd. Impregnated cathode and method for manufacturing the same
EP1267377A1 (en) * 1997-07-09 2002-12-18 Matsushita Electric Industrial Co., Ltd. Method for manufacturing an impregnated cathode
US6705913B2 (en) 1997-07-09 2004-03-16 Matsushita Electric Industrial Co., Ltd. Method for manufacturing impregnated cathode having a cathode pellet
US6351061B1 (en) 1997-09-26 2002-02-26 Matsushita Electric Industrial Co., Ltd. Cathode, method for manufacturing the cathode, and picture tube
US6565402B2 (en) 1997-09-26 2003-05-20 Matsushita Electric Industrial Co., Ltd. Cathode, method for manufacturing the cathode, and picture tube

Also Published As

Publication number Publication date
EP0052047B1 (en) 1986-01-08
FR2494035B1 (en) 1983-05-13
US4494035A (en) 1985-01-15
DE3173470D1 (en) 1986-02-20
EP0052047B2 (en) 1990-05-02
JPS57107534A (en) 1982-07-05
FR2494035A1 (en) 1982-05-14

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