US2614942A - Thermionic cathode - Google Patents

Thermionic cathode Download PDF

Info

Publication number
US2614942A
US2614942A US112246A US11224649A US2614942A US 2614942 A US2614942 A US 2614942A US 112246 A US112246 A US 112246A US 11224649 A US11224649 A US 11224649A US 2614942 A US2614942 A US 2614942A
Authority
US
United States
Prior art keywords
cathode
thorium oxide
mixture
sintered
body
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.)
Expired - Lifetime
Application number
US112246A
Inventor
Loosjes Robert
Antonius Josephus V Genuchten
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.)
Hartford National Bank and Trust Co
Original Assignee
Hartford National Bank and Trust Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL278121X priority Critical
Application filed by Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
Application granted granted Critical
Publication of US2614942A publication Critical patent/US2614942A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00Apparatus 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
    • H01J9/02Manufacture of electrodes or electrode systems
    • H01J9/04Manufacture of electrodes or electrode systems of thermionic cathodes
    • H01J9/042Manufacture, activation of the emissive part
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00Details 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
    • H01J1/02Main electrodes
    • H01J1/13Solid thermionic cathodes
    • H01J1/14Solid thermionic cathodes characterised by the material
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00Gas-discharge or vapour-discharge lamps
    • H01J61/02Details
    • H01J61/04Electrodes; Screens; Shields
    • H01J61/06Main electrodes
    • H01J61/073Main electrodes for high-pressure discharge lamps
    • H01J61/0735Main electrodes for high-pressure discharge lamps characterised by the material of the electrode
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/29Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913Rod, strand, filament or fiber
    • Y10T428/2933Coated or with bond, impregnation or core
    • Y10T428/294Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
    • Y10T428/2958Metal or metal compound in coating
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00Stock material or miscellaneous articles
    • Y10T428/29Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913Rod, strand, filament or fiber
    • Y10T428/298Physical dimension

Description

Patented Oct. 21, 1952 THERMIONIC CATHODE Robert Loosjes and Antonius Josephus v.

Genuchten, Eindhoven, Netherlands, assigncrs to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application August 25, 1949, Serial No. 112,246 In the Netherlands September 11i, 1948 3 Claims. l

This invention relates to cathodes the emission properties of which are determined by thorium oxide, the cathode body consisting of a sintered mixture of thorium oxide and a refractory metal such as tungsten.

The aforementioned type of cathodes have already been used in gaseous discharge lamps in which they are heated by the discharge. If the mixture is pressed at a suiciently high pressure and sintered at a sufficiently high temperature, the cathode body has great mechanical rigidity. A disadvantage is that the oxide-metal mixture is black so that the radiation has a comparatively high value. Furthermore, the specific emission is comparatively low.

The object of the invention is to provide an improvement in the above-mentioned cathode.

According to the invention, a cathode the emission properties of which are determined by thorium oxide, and the cathode body of which consists of a mixture of thorium oxide and a refractory metal such as tungsten which mixture is pressed at high pressure and subsequently sintered, is covered with a thin layer of thorium oxide which is secured by sintering to the cathode body. Since thorium oxide is white, the thermal radiation is comparatively small, whilst the specific electron emission of thorium oxide is materially higher than that of the mixture of thorium-oxide metal. Activation of the cathode is not required, since the cathode is capable of emitting electrons directly after incorporation in a tube. The invention will now be described with reference to the accompanying drawing in which the sole figure is a view, in cross-section, of an electric discharge tube comprising one form of cathode in accordance with the invention.

Referring to the figure, an electric discharge tube l comprises an envelope 2 enclosing a cathode 3, a control grid 4 and an anode 5. The cathode 3 comprises a body of a sintered mixture of thorium oxide and a refractory metal, e. g., tungsten, which body `has a thin layer 6 of thorium oxide sintered thereto. The composition of the cathode will now be explained more fully by reference to the following example.

A mixture consisting of equal amounts by weight of thorium oxide and of tungsten is pressed at high pressure to form a cylindrical vtemperatures up to 2300 C. Theheating of the cathode takes place evenly due to the intimate mixture of the tungsten and the thorium oxide. If the cathode is operated by pulses, the specific emission may be up to 50 amps/cm.2 at a temperature of 2200 K. The period of life is Very long.

What we claim is: i

1. A cathode comprising a body composed of a sintered mixture of thorium oxide and a refractory metal, and a discrete thin layer of given thickness of thorium oxide covering said mixture of thorium oxide and refractory metal and sin tered to said body.

2. A cathode comprising a body composed of a sintered mixture of thorium oxide and tungsten, and a discretethin layer of given thickness of thorium oxide covering said mixture of thorium oxide and refractory metal and sintered to said ROBERT LOOSJES. ANTONIUS J OSEPHUS V. GENUCHTEN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,339,392 Garner Jan. l8rJ 1944 2,477,601

Hanson Aug. 2, 1949

Claims (1)

1. A CATHODE COMPRISING A BODY COMPOSED OF A SINTERED MIXTURE OF THORIUM OXIDE AND A REFRACTORY METAL, AND A DISCRETE THIN LAYER OF GIVEN THICKNESS OF THORIUM OXIDE COVERING SAID MIXTURE OF THORIUM OXIDE AND REFRACTORY METAL AND SINTERED TO SAID BODY.
US112246A 1948-09-14 1949-08-25 Thermionic cathode Expired - Lifetime US2614942A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
NL278121X 1948-09-14

Publications (1)

Publication Number Publication Date
US2614942A true US2614942A (en) 1952-10-21

Family

ID=19782192

Family Applications (1)

Application Number Title Priority Date Filing Date
US112246A Expired - Lifetime US2614942A (en) 1948-09-14 1949-08-25 Thermionic cathode

Country Status (7)

Country Link
US (1) US2614942A (en)
BE (1) BE491070A (en)
CH (1) CH278121A (en)
DE (1) DE813573C (en)
FR (1) FR995225A (en)
GB (1) GB666053A (en)
NL (1) NL70864C (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2717975A (en) * 1951-03-30 1955-09-13 Wihtol Weltis Cathodes for electron tubes
US2845515A (en) * 1953-03-12 1958-07-29 Raytheon Mfg Co Semimetallic resistive filaments
US2847328A (en) * 1957-03-04 1958-08-12 James E Cline Method of making thorium oxide cathodes
US3558966A (en) * 1967-03-01 1971-01-26 Semicon Associates Inc Directly heated dispenser cathode
US3973155A (en) * 1975-01-31 1976-08-03 Westinghouse Electric Corporation Incandescent source of visible radiations
US4333035A (en) * 1979-05-01 1982-06-01 Woodland International Corporation Areal array of tubular electron sources
US4438557A (en) * 1979-05-01 1984-03-27 Woodland International Corporation Method of using an areal array of tubular electron sources
WO2009045605A2 (en) * 2007-09-28 2009-04-09 General Electric Company Thermo-optically functional compositions, systems and methods of making

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1009727B (en) * 1953-01-10 1957-06-06 Deutsche Elektronik Gmbh A method for producing solid, guthaftender emission layers of thorium oxide on a Traegermetall of tungsten or molybdenum
US2881512A (en) * 1954-06-16 1959-04-14 Cie Generale De Telegraphite S Composition for sintered barium cathodes
DE1080700B (en) * 1958-05-17 1960-04-28 Deutsche Elektronik Gmbh A process for producing an indirectly heated cathode, especially for magnetron high resonant power, and produced by this process cathode

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2339392A (en) * 1942-10-06 1944-01-18 Rca Corp Cathode
US2477601A (en) * 1947-06-11 1949-08-02 Raytheon Mfg Co Directly heated cathode

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2339392A (en) * 1942-10-06 1944-01-18 Rca Corp Cathode
US2477601A (en) * 1947-06-11 1949-08-02 Raytheon Mfg Co Directly heated cathode

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2717975A (en) * 1951-03-30 1955-09-13 Wihtol Weltis Cathodes for electron tubes
US2845515A (en) * 1953-03-12 1958-07-29 Raytheon Mfg Co Semimetallic resistive filaments
US2847328A (en) * 1957-03-04 1958-08-12 James E Cline Method of making thorium oxide cathodes
US3558966A (en) * 1967-03-01 1971-01-26 Semicon Associates Inc Directly heated dispenser cathode
US3973155A (en) * 1975-01-31 1976-08-03 Westinghouse Electric Corporation Incandescent source of visible radiations
US4333035A (en) * 1979-05-01 1982-06-01 Woodland International Corporation Areal array of tubular electron sources
US4438557A (en) * 1979-05-01 1984-03-27 Woodland International Corporation Method of using an areal array of tubular electron sources
WO2009045605A2 (en) * 2007-09-28 2009-04-09 General Electric Company Thermo-optically functional compositions, systems and methods of making
WO2009045605A3 (en) * 2007-09-28 2010-03-18 General Electric Company Thermo-optically functional compositions, systems and methods of making

Also Published As

Publication number Publication date
NL70864C (en)
DE813573C (en) 1951-09-13
CH278121A (en) 1951-09-30
GB666053A (en) 1952-02-06
FR995225A (en) 1951-11-29
BE491070A (en)

Similar Documents

Publication Publication Date Title
Dushman Thermionic emission
Schulz et al. Excitation of metastable levels in helium near threshold
US20050029917A1 (en) Magnetron
US2708726A (en) Electron discharge device employing secondary electron emission and method of making same
US3374386A (en) Field emission cathode having tungsten miller indices 100 plane coated with zirconium, hafnium or magnesium on oxygen binder
US2121589A (en) Emissive incandescent cathode
US4594220A (en) Method of manufacturing a scandate dispenser cathode and dispenser cathode manufactured by means of the method
GB922789A (en) Low temperature thermionic energy converter
US2912611A (en) Thermionic cathodes
Cronin Modern dispenser cathodes
Levi New dispenser type thermionic cathode
US2698913A (en) Cathode structure
US3798492A (en) Emissive electrode
US3558966A (en) Directly heated dispenser cathode
US2842706A (en) Cold cathode vacuum tube
US2543728A (en) Incandescible cathode
US3244929A (en) Multi-work function cathode
Vancil et al. Scandate dispenser cathodes with sharp transition and their application in microwave tubes
US2198329A (en) Electric discharge tube
US2528547A (en) Hydrogen thyratron
US2449113A (en) Electric discharge device
US2147447A (en) Glow cathode
GB568962A (en) Improvements in or relating to cathodes for electron discharge devices
GB1265881A (en)
US4275330A (en) Electric discharge lamp having a cathode with cesium metal oxide