US2472189A - Thermionic tube having a secondary-emission electrode - Google Patents

Thermionic tube having a secondary-emission electrode Download PDF

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Publication number
US2472189A
US2472189A US480102A US48010243A US2472189A US 2472189 A US2472189 A US 2472189A US 480102 A US480102 A US 480102A US 48010243 A US48010243 A US 48010243A US 2472189 A US2472189 A US 2472189A
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United States
Prior art keywords
electrode
emission electrode
emission
caesium
thermionic tube
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Expired - Lifetime
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US480102A
Inventor
Bienfait Henri
Veenemans Cornelis Frederik
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/12—Manufacture of electrodes or electrode systems of photo-emissive cathodes; of secondary-emission electrodes
    • H01J9/125—Manufacture of electrodes or electrode systems of photo-emissive cathodes; of secondary-emission electrodes of secondary emission electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J7/00—Details not provided for in the preceding groups and common to two or more basic types of discharge tubes or lamps
    • H01J7/14—Means for obtaining or maintaining the desired pressure within the vessel
    • H01J7/18—Means for absorbing or adsorbing gas, e.g. by gettering
    • H01J7/183—Composition or manufacture of getters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/04—Manufacture of electrodes or electrode systems of thermionic cathodes
    • H01J9/042—Manufacture, activation of the emissive part
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/32—Secondary emission electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/922—Static electricity metal bleed-off metallic stock
    • Y10S428/9335—Product by special process
    • Y10S428/938—Vapor deposition or gas diffusion
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12014—All metal or with adjacent metals having metal particles
    • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
    • Y10T428/12063—Nonparticulate metal component
    • Y10T428/12069—Plural nonparticulate metal components
    • Y10T428/12076—Next to each other
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12014—All metal or with adjacent metals having metal particles
    • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
    • Y10T428/12063—Nonparticulate metal component
    • Y10T428/12097—Nonparticulate component encloses particles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12771—Transition metal-base component
    • Y10T428/12778—Alternative base metals from diverse categories

Definitions

  • This invention relates to thermionic tubes provided with a secondary-emission electrode and more particularly to such tubes in which the secondary emission is brought about by an active layer consisting of caesium oxide, which is applied to the secondary-emission electrode.
  • Thermionic tubes containing a secondaryemission electrode covered with caesium oxide as an active material are already known.
  • Figure 1 shows the steps of the method according to the invention and Figure 2 shows an enlarged cross-section of a portion of an electrode made in accordance with the invention.
  • the finished electrode shown in Figure 2 comprises a base on which heat-radiating black metal particles are disposed and about which particles emissive material is deposited.
  • the cooling of the secondary-emission electrode is desirable, since the heating of the electrode produced during operation injuriously affects the emission.
  • the temperature of the secondary-emission electrode during operation must in general not exceed C.
  • a thermionic tube according to the invention contains at least one secondary-emission electrode a part of whose surface contains caesium oxide as an active secondary-emission material, the other non-activated parts of the surface of the electrode or electrodes being covered with the product obtained by reduction of one or more of the oxides of nickel, tungsten, zirconium or molybdenum.
  • the reduction of these metal oxides has the effect of producing on the secondary-emission electrode a layer consisting of the metal having such structure as to exhibit a black appearance.
  • This metal may still be mixed with a quantity of metal oxide, since the reduction is effected only partly.
  • a secondary-emission electrode is manufactured by applying, prior to its incorporation in the tube, to a part of the surface a layer consisting of one or more of the oxides of the metals nickel, tungsten, zirconium or molybdenum, and subsequently reducing this layer at low temperature.
  • the application of the metal oxides to the electrode may be efiected, for example, by spraying, dipping, or with the aid of the cataphoretic process.
  • the reduction at low temperature has the effect of producing a non-hardened, finely distributed structure of the metal which is particularly adapted to the emission of heat and the adherence of small quantities of caesium.
  • the reduction is efiected during about 10 minutes at a temperature of about 700 C.
  • the reduction may take place, for example, in a hydrogen atmosphere.
  • a secondary-emissive electrode for a thermionic tube having a multiplicity of parts on its surface comprised of black particles of nickel

Description

June 7, 1949. H. BIENFAIT ETAL 2,472,189
THERMIONIC TUBE HAVING A SECONDARY-EMISSION ELECTRODE Filed March 22, 1943 APPLY OXIDE OF NICKEL TUNGSTEN ZIRCONIUM OR MOLYBDENUM TO ELECTRODE SURFACE BEFORE PLACING IN TUBE REDUCE PART OF OXIDE AT LOW TEMPERATURE To FORM FINELY' DIVIDED BLACK METAL PARTICLES APPLY CAESIUM TO ELECTRODE SURFACE BY VAPORIZATION FIG. I
EMISSIVE MATERIAL HEAT RADIATING BLACK METAL PARTICLES CORNELIS FREDERIK VEENEMANS HENRI BIENFAIT INVENTORS ATTORNEY\ Patented June 7, 1949 THERMIONIC TUBE HAVING A SECONDARY- EIWISSION ELECTRODE Henri Bienfait and Cornelis Frederik Veenemans, Eindhoven, Netherlands, assignors to Hartford National Bank and Trust Company, Hartford,
Conn., as trustee Application March 22, 1943, Serial No. 480,102 In the Netherlands July 3, 1941 Section 1, Public Law 690, August 8, 1946 Patent expires July 3, 1961 2 Claims.
This invention relates to thermionic tubes provided with a secondary-emission electrode and more particularly to such tubes in which the secondary emission is brought about by an active layer consisting of caesium oxide, which is applied to the secondary-emission electrode.
Thermionic tubes containing a secondaryemission electrode covered with caesium oxide as an active material are already known.
Further, it is already known to cool secondaryemission electrodes; to this end, it has been suggested either to connect cooling bodies to the secondary-emission electrodes, or to cool the latter with the aid of a running liquid.
Furthermore, in thermionic tubes it was already general practice to cover definite electrodes with a black substance in order to improve the radiation of heat and thus maintain the temperature of the electrode concerned at a low value. The black material used is frequently carbon.
In the accompanying drawing Figure 1 shows the steps of the method according to the invention and Figure 2 shows an enlarged cross-section of a portion of an electrode made in accordance with the invention.
In Figure 1 the rectangles represent the successive steps of the method of the invention. The finished electrode shown in Figure 2 comprises a base on which heat-radiating black metal particles are disposed and about which particles emissive material is deposited.
It has been found, however, that carbon is not adapted to be applied to parts of secondaryemission electrodes which contain caesium oxide as active material, since carbon very easily absorbs or adsorbs caesium. Since the active caesium coating is almost solely obtained by applying caesium to the secondary-emission electrode by vaporisation and subsequently oxidising, good dosing of the caesium is impossible if part of the electrode is covered with carbon. On the other hand, it is desirable that on the secondary-emission electrode or in the vicinity thereof there be a material capable of binding small quantities of caesium.
Also the cooling of the secondary-emission electrode is desirable, since the heating of the electrode produced during operation injuriously affects the emission. The temperature of the secondary-emission electrode during operation must in general not exceed C.
A thermionic tube according to the invention contains at least one secondary-emission electrode a part of whose surface contains caesium oxide as an active secondary-emission material, the other non-activated parts of the surface of the electrode or electrodes being covered with the product obtained by reduction of one or more of the oxides of nickel, tungsten, zirconium or molybdenum.
The reduction of these metal oxides has the effect of producing on the secondary-emission electrode a layer consisting of the metal having such structure as to exhibit a black appearance. This metal may still be mixed with a quantity of metal oxide, since the reduction is effected only partly.
According to a process which also forms part of the invention, a secondary-emission electrode is manufactured by applying, prior to its incorporation in the tube, to a part of the surface a layer consisting of one or more of the oxides of the metals nickel, tungsten, zirconium or molybdenum, and subsequently reducing this layer at low temperature.
The application of the metal oxides to the electrode may be efiected, for example, by spraying, dipping, or with the aid of the cataphoretic process.
The reduction at low temperature has the effect of producing a non-hardened, finely distributed structure of the metal which is particularly adapted to the emission of heat and the adherence of small quantities of caesium.
According to one particular example of a process according to the invention, the reduction is efiected during about 10 minutes at a temperature of about 700 C. The reduction may take place, for example, in a hydrogen atmosphere.
We claim:
1. A secondary-emissive electrode for a thermionic tube having a multiplicity of parts on its surface comprised of black particles of nickel,
and secondary-emissive material on the said electrode around said nickel particles.
2. The process of making a secondary-emission electrode for a thermionic tube which comprises depositing nickel oxide on the surface of said electrode, reducing said oxide to a metal in a. hydrogen atmosphere at a temperature of about 700 C., and depositing secondary emissive maumber terial around said metal particles. 2,123,024 HENRI IBIENFAIT. 2,146,099 CORNELIS FREDERIK VEENEMANS. 2, 2,190,695 REFERENCES CITED 2,198,329 2,204,252
The following references are of record in the m file of this patent:
UNITED STATES PATENTS Name Date Piore et a1 July 5, 1938 De Boer et a1 Feb. '7, 1939 Schreinemachers Aug. 29, 1939 Bruining et a1 Feb. 20, 1940 Bruining et a1 Apr. 23, 1940 Krenzlen June 11, 1940
US480102A 1941-07-03 1943-03-22 Thermionic tube having a secondary-emission electrode Expired - Lifetime US2472189A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL242721X 1941-07-03

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US (1) US2472189A (en)
BE (1) BE446289A (en)
CH (1) CH242721A (en)
FR (1) FR883717A (en)
GB (1) GB613946A (en)
NL (1) NL59008C (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2858470A (en) * 1955-02-02 1958-10-28 Bell Telephone Labor Inc Cathode for electron discharge devices
US2996795A (en) * 1955-06-28 1961-08-22 Gen Electric Thermionic cathodes and methods of making
US3041209A (en) * 1955-06-28 1962-06-26 Gen Electric Method of making a thermionic cathode
US3342634A (en) * 1962-10-17 1967-09-19 Philips Corp Method of producing black, metalcontaining surface layers
US3376461A (en) * 1964-12-28 1968-04-02 Varian Associates Thermionic cathodes and high frequency electron discharge devices
US3958146A (en) * 1974-02-08 1976-05-18 Gte Sylvania Incorporated Fast warm up picture tube cathode cap having high heat emissivity surface on the interior thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2123024A (en) * 1936-05-29 1938-07-05 Rca Corp Electrode for electric discharge devices
US2146099A (en) * 1936-02-10 1939-02-07 Philips Nv Secondary electron emitter and method of making it
US2171227A (en) * 1937-08-09 1939-08-29 Philips Nv Secondary electron emitter and method of making it
US2190695A (en) * 1937-04-02 1940-02-20 Rca Corp Secondary electron emitter and method of making it
US2198329A (en) * 1937-03-25 1940-04-23 Rca Corp Electric discharge tube
US2204252A (en) * 1938-07-28 1940-06-11 Fides Gmbh Secondary electron emitter and method of making it

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2146099A (en) * 1936-02-10 1939-02-07 Philips Nv Secondary electron emitter and method of making it
US2123024A (en) * 1936-05-29 1938-07-05 Rca Corp Electrode for electric discharge devices
US2198329A (en) * 1937-03-25 1940-04-23 Rca Corp Electric discharge tube
US2190695A (en) * 1937-04-02 1940-02-20 Rca Corp Secondary electron emitter and method of making it
US2171227A (en) * 1937-08-09 1939-08-29 Philips Nv Secondary electron emitter and method of making it
US2204252A (en) * 1938-07-28 1940-06-11 Fides Gmbh Secondary electron emitter and method of making it

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2858470A (en) * 1955-02-02 1958-10-28 Bell Telephone Labor Inc Cathode for electron discharge devices
US2996795A (en) * 1955-06-28 1961-08-22 Gen Electric Thermionic cathodes and methods of making
US3041209A (en) * 1955-06-28 1962-06-26 Gen Electric Method of making a thermionic cathode
US3342634A (en) * 1962-10-17 1967-09-19 Philips Corp Method of producing black, metalcontaining surface layers
US3376461A (en) * 1964-12-28 1968-04-02 Varian Associates Thermionic cathodes and high frequency electron discharge devices
US3958146A (en) * 1974-02-08 1976-05-18 Gte Sylvania Incorporated Fast warm up picture tube cathode cap having high heat emissivity surface on the interior thereof

Also Published As

Publication number Publication date
CH242721A (en) 1946-05-31
NL59008C (en)
GB613946A (en) 1948-12-07
BE446289A (en)
FR883717A (en) 1943-07-13

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