EP0052047A1 - Thermoelektronische Kathode - Google Patents

Thermoelektronische Kathode 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
Authority
EP
European Patent Office
Prior art keywords
cathode according
tungsten
impregnated
thermoelectronic
barium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP81401713A
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English (en)
French (fr)
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EP0052047B1 (de
EP0052047B2 (de
Inventor
Pierre Palluel
Arvind Shroff
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thomson CSF SA
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Publication date
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Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0052047A1 publication Critical patent/EP0052047A1/de
Publication of EP0052047B1 publication Critical patent/EP0052047B1/de
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Publication of EP0052047B2 publication Critical patent/EP0052047B2/de
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Classifications

    • 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.

Landscapes

  • Solid Thermionic Cathode (AREA)
  • Microwave Tubes (AREA)
EP81401713A 1980-11-07 1981-10-27 Thermoelektronische Kathode Expired - Lifetime EP0052047B2 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8023884A FR2494035A1 (fr) 1980-11-07 1980-11-07 Cathode thermo-electronique pour tube hyperfrequences et tube incorporant une telle cathode
FR8023884 1980-11-07

Publications (3)

Publication Number Publication Date
EP0052047A1 true EP0052047A1 (de) 1982-05-19
EP0052047B1 EP0052047B1 (de) 1986-01-08
EP0052047B2 EP0052047B2 (de) 1990-05-02

Family

ID=9247818

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81401713A Expired - Lifetime EP0052047B2 (de) 1980-11-07 1981-10-27 Thermoelektronische Kathode

Country Status (5)

Country Link
US (1) US4494035A (de)
EP (1) EP0052047B2 (de)
JP (1) JPS57107534A (de)
DE (1) DE3173470D1 (de)
FR (1) FR2494035A1 (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2596198A1 (fr) * 1986-03-19 1987-09-25 Thomson Csf Cathodes pour klystron a faisceaux multiples, klystron comportant de telles cathodes et procede de fabrication de telles cathodes
EP0282040A1 (de) * 1987-03-10 1988-09-14 Siemens Aktiengesellschaft Vorratskathode, insbesondere Metall-Kapillar-Kathode, für elektrische Entladungsgefässe
EP0401068A1 (de) * 1989-05-30 1990-12-05 Thomson Tubes Electroniques Imprägnierte thermiorische Kathode für Elektronenröhre
FR2651369A1 (fr) * 1989-08-22 1991-03-01 Asea Brown Boveri Gyrotron quasi optique.
EP0757370A1 (de) * 1995-07-31 1997-02-05 Philips Patentverwaltung GmbH Elektrische Entladungsröhre oder Entladungslampe und Scandat-Vorratskathode
EP0890972A1 (de) * 1997-07-09 1999-01-13 Matsushita Electronics Corporation Imprägnierte Kathode und Verfahren zu ihrer Herstellung
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 (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0719530B2 (ja) * 1984-06-29 1995-03-06 株式会社日立製作所 陰極線管
JPH0416344Y2 (de) * 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 (fr) * 2001-12-10 2003-06-13 Thomson Licensing Sa Cathode pour tube a vide a duree de vie amelioree
CN103311066B (zh) * 2013-06-03 2015-08-19 哈尔滨工业大学 具有内芯的用于航天器自持空心阴极的发射体
CN116387116B (zh) * 2023-03-29 2025-05-30 中国科学院空天信息创新研究院 浸渍型阴极及其制备方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1093241A (de) * 1953-02-16 1955-05-02
FR1124860A (fr) * 1954-06-29 1956-10-19 Siemens Ag Cathode à chauffage indirect pour tube de décharge électrique
FR2069601A5 (de) * 1969-11-21 1971-09-03 Philips Nv
US3719856A (en) * 1971-05-19 1973-03-06 O Koppius Impregnants for dispenser cathodes
FR2356263A1 (fr) * 1976-06-21 1978-01-20 Varian Associates Cathode en iridium pour tube a hyperfrequence
FR2390825A1 (fr) * 1977-05-13 1978-12-08 Thomson Csf Cathode thermo-ionique a grille incorporee, son procede de fabrication et tube electronique comportant une telle cathode
DE2808134A1 (de) * 1978-02-25 1979-08-30 Licentia Gmbh Vorratskathode
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 (de) * 1954-12-06
US3076915A (en) * 1954-12-24 1963-02-05 Egyesuelt Izzolampa Cathode assembly and method of making same
NL272981A (de) * 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 (de) * 1972-09-18 1974-03-28 Patra Patent Treuhand Elektrode mit einem poroesen sinterkoerper
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 (de) * 1953-02-16 1955-05-02
FR1124860A (fr) * 1954-06-29 1956-10-19 Siemens Ag Cathode à chauffage indirect pour tube de décharge électrique
FR2069601A5 (de) * 1969-11-21 1971-09-03 Philips Nv
US3719856A (en) * 1971-05-19 1973-03-06 O Koppius Impregnants for dispenser cathodes
FR2356263A1 (fr) * 1976-06-21 1978-01-20 Varian Associates Cathode en iridium pour tube a hyperfrequence
FR2390825A1 (fr) * 1977-05-13 1978-12-08 Thomson Csf Cathode thermo-ionique a grille incorporee, son procede de fabrication et tube electronique comportant une telle cathode
DE2808134A1 (de) * 1978-02-25 1979-08-30 Licentia Gmbh Vorratskathode
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 (fr) * 1986-03-19 1987-09-25 Thomson Csf Cathodes pour klystron a faisceaux multiples, klystron comportant de telles cathodes et procede de fabrication de telles cathodes
EP0282040A1 (de) * 1987-03-10 1988-09-14 Siemens Aktiengesellschaft Vorratskathode, insbesondere Metall-Kapillar-Kathode, für elektrische Entladungsgefässe
EP0401068A1 (de) * 1989-05-30 1990-12-05 Thomson Tubes Electroniques Imprägnierte thermiorische Kathode für Elektronenröhre
FR2647952A1 (fr) * 1989-05-30 1990-12-07 Thomson Tubes Electroniques Cathode thermoelectronique impregnee pour tube electronique
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 (de) * 1989-08-22 1991-10-15 Asea Brown Boveri
FR2651369A1 (fr) * 1989-08-22 1991-03-01 Asea Brown Boveri Gyrotron quasi optique.
EP0757370A1 (de) * 1995-07-31 1997-02-05 Philips Patentverwaltung GmbH Elektrische Entladungsröhre oder Entladungslampe und Scandat-Vorratskathode
EP0890972A1 (de) * 1997-07-09 1999-01-13 Matsushita Electronics Corporation Imprägnierte Kathode und Verfahren zu ihrer Herstellung
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 (de) * 1997-07-09 2002-12-18 Matsushita Electric Industrial Co., Ltd. Verfahren zur Herstellung einer imprägnierten Kathode
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
FR2494035A1 (fr) 1982-05-14
EP0052047B1 (de) 1986-01-08
US4494035A (en) 1985-01-15
FR2494035B1 (de) 1983-05-13
JPS57107534A (en) 1982-07-05
EP0052047B2 (de) 1990-05-02
DE3173470D1 (en) 1986-02-20

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