US2624024A - Cathode for use in electron discharge tubes - Google Patents

Cathode for use in electron discharge tubes Download PDF

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Publication number
US2624024A
US2624024A US188542A US18854250A US2624024A US 2624024 A US2624024 A US 2624024A US 188542 A US188542 A US 188542A US 18854250 A US18854250 A US 18854250A US 2624024 A US2624024 A US 2624024A
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Prior art keywords
cathode
wires
discharge tubes
electron discharge
alkaline earth
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Expired - Lifetime
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US188542A
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Jansen Marinus Jacobus
Lemmens Hendrikus Johannes
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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
    • 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

Definitions

  • This invention relates to cathodes for use in electron discharge tubes and containing a supply of alkaline earth metal compounds in a supply chamber, the wall of the supply chamber consisting at least partly of a structure of fine wires.
  • the wall of known chambers consists of plaited strands of fine wires (so-called stranded wires).
  • the known cathodes suffer from the disadvantage that the apertures in the wall of the cathode body are of a comparatively irregular size and mass production of cathodes with uniform apertures is in practice not possible. Due to this, the rate at which the alkaline earth metal compounds reach the surface of the oathode is not exactly determined, whereby both the electron emission and the life of the cathode may be adversely aifected.
  • a cathode which contains a supply of alkaline earth metal compounds and the wall of which consists at least partly of a structure of fine wires, is characterised in that the wires extend at right angles to the electron-emitting surface.
  • a slice may be cut from a strand of wires drawn out to the desired size and this slice may subsequently be fitted in the wall of the cathode body.
  • Figs. 1 and 2 are an axial cross-section and a plan view, respectively, of a fiat cathode according to the invention.
  • the wires may consist of tungsten, molybdenum or tantalum.
  • the reference numeral l designates a slice which is cut from a strand of fine wires drawn out together.
  • tungsten wires of 200 p. are placed in a molybdenum tube, inner and outer diameter 6 and 10 mm. respectively, and drawn out to a diameter of 3 mm.
  • This slice 1 is welded in a molybdenum bush 2, with the aid of a spot-welding apparatus, to the bottom of which a second molybdenum bush 3 is welded.
  • a helical filament 4 is provided within the bush 3.
  • the supply of alkaline earth metal compounds is designated 5.
  • tantalum fittings may be used.
  • a cathode comprising a structure forming an internal cavity containing a supply of alkaline earth metal compounds, one wall portion of said structure comprising a plurality of wires each about one-tenth of a millimeter in diameter and extending at right-angles to the surface of the alkaline earth metal compounds in the cavity, said wires consisting of a metal selected from the group consisting of tungsten, molybdenum and tantalum.
  • a cathode comprising a structure of molybdenum forming an internal cavity containing a supply of alkaline earth metal compounds, one wall of said structure comprising a plurality of tungsten wires each about one-tenth of a millimeter in diameter extending at right angles to the surface of the alkaline earth metal compounds.

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  • Solid Thermionic Cathode (AREA)

Description

Dec. 30, 1952 M. J. JANSEN ETAL CATHODE FOR USE IN ELECTRON DISCHARGE TUBES Filed Oct. 5. 1950 =IlllIlIlllllillllllillliilfl'l" INVENTORS MARINUS J. JANSEN.
HENDRIKUS J.%LEMMENS BY AGENT Patented Dec. 30, 1952 CATHODE FOR USE IN ELECTRON DISCHARGE TUBES Marinus Jacobus Jansen and Hendrikus Johannes Lemmens, Eindhoven, Netherlands, assignors to Hartford National Bank and Trust Company, Hartford, (301111., as trustee Application October 5, 1950, Serial No. 188,542 In the Netherlands October 26, 1949 2 Claims. 1
This invention relates to cathodes for use in electron discharge tubes and containing a supply of alkaline earth metal compounds in a supply chamber, the wall of the supply chamber consisting at least partly of a structure of fine wires.
The wall of known chambers consists of plaited strands of fine wires (so-called stranded wires). Owing to this, the known cathodes suffer from the disadvantage that the apertures in the wall of the cathode body are of a comparatively irregular size and mass production of cathodes with uniform apertures is in practice not possible. Due to this, the rate at which the alkaline earth metal compounds reach the surface of the oathode is not exactly determined, whereby both the electron emission and the life of the cathode may be adversely aifected.
According to the invention, a cathode which contains a supply of alkaline earth metal compounds and the wall of which consists at least partly of a structure of fine wires, is characterised in that the wires extend at right angles to the electron-emitting surface. For a cathode having a fiat electron-emitting surface, a slice may be cut from a strand of wires drawn out to the desired size and this slice may subsequently be fitted in the wall of the cathode body.
When the wires are drawn out they are compacted to a high degree and only very small interstices remain between them.
In order that the invention may be more clearly understood and readily carried into effect, it will now be described more fully with reference to the accompanying diagrammatic drawin given by way of example, wherein Figs. 1 and 2 are an axial cross-section and a plan view, respectively, of a fiat cathode according to the invention.
The wires may consist of tungsten, molybdenum or tantalum.
In Figs. 1 and 2, the reference numeral l designates a slice which is cut from a strand of fine wires drawn out together. For example,
about 800 tungsten wires of 200 p. are placed in a molybdenum tube, inner and outer diameter 6 and 10 mm. respectively, and drawn out to a diameter of 3 mm. This slice 1 is welded in a molybdenum bush 2, with the aid of a spot-welding apparatus, to the bottom of which a second molybdenum bush 3 is welded. Within the bush 3, a helical filament 4 is provided. The supply of alkaline earth metal compounds is designated 5. Instead of the molybdenum bushes 2 and 3 and tube surrounding the wires, tantalum fittings may be used.
What we claim is:
l. A cathode comprising a structure forming an internal cavity containing a supply of alkaline earth metal compounds, one wall portion of said structure comprising a plurality of wires each about one-tenth of a millimeter in diameter and extending at right-angles to the surface of the alkaline earth metal compounds in the cavity, said wires consisting of a metal selected from the group consisting of tungsten, molybdenum and tantalum.
2. A cathode comprising a structure of molybdenum forming an internal cavity containing a supply of alkaline earth metal compounds, one wall of said structure comprising a plurality of tungsten wires each about one-tenth of a millimeter in diameter extending at right angles to the surface of the alkaline earth metal compounds.
MARINUS J ACOBUS J AN SEN. I-IENDRIKUS J OHANNES LEMMENS.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,107,945 Hull et a1 Feb. 8, 1938 2,131,204 Waldschmidt Sept. 2'7, 1938 2,416,661 Lawton Feb. 25, 1947
US188542A 1949-10-26 1950-10-05 Cathode for use in electron discharge tubes Expired - Lifetime US2624024A (en)

Applications Claiming Priority (1)

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NL2624024X 1949-10-26

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721372A (en) * 1951-06-30 1955-10-25 Philips Corp Incandescible cathodes
US2722626A (en) * 1953-02-16 1955-11-01 Philips Corp Thermionic cathode
US2750527A (en) * 1951-11-19 1956-06-12 Siemens Ag Cathode for electrical discharge device
US2786957A (en) * 1953-04-02 1957-03-26 Csf Emissive cathodes
US2786259A (en) * 1950-11-18 1957-03-26 Philips Corp Method of making supply cathodes and supply cathodes manufactured by means of these methods
US2822499A (en) * 1955-02-17 1958-02-04 Bell Telephone Labor Inc Cathodes for electron discharge devices
US2848644A (en) * 1953-01-19 1958-08-19 Philips Corp Thermionic cathode
US2888592A (en) * 1954-07-22 1959-05-26 Gen Electric Cathode structure
US2902620A (en) * 1953-03-04 1959-09-01 Egyesuelt Izzolampa Supply cathode
US2928013A (en) * 1954-12-23 1960-03-08 Siemens Ag Electrical discharge device
US2931934A (en) * 1955-02-05 1960-04-05 Egyesuelt Izzolampa Indirectly heated supply cathode
US3025428A (en) * 1959-10-15 1962-03-13 Kuthe Lab Inc Cathode structure
US3128531A (en) * 1959-10-22 1964-04-14 Nat Res Dev Dynodes for electron discharge tubes and methods of making same
US3842309A (en) * 1970-11-12 1974-10-15 Philips Corp Method of manufacturing a storage cathode and cathode manufactured by said method
US4229873A (en) * 1978-09-15 1980-10-28 Bykhovskij David G Method of producing nonconsumable electrode for use in arc techniques

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1123051B (en) * 1959-11-13 1962-02-01 Siemens Ag Emission cathode, especially for high vacuum tubes

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2107945A (en) * 1934-11-20 1938-02-08 Gen Electric Cathode structure
US2131204A (en) * 1936-01-15 1938-09-27 Siemens Ag Indirectly heated thermionic cathode
US2416661A (en) * 1943-05-28 1947-02-25 Gen Electric Dispenser type cathode electric discharge device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2107945A (en) * 1934-11-20 1938-02-08 Gen Electric Cathode structure
US2131204A (en) * 1936-01-15 1938-09-27 Siemens Ag Indirectly heated thermionic cathode
US2416661A (en) * 1943-05-28 1947-02-25 Gen Electric Dispenser type cathode electric discharge device

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2786259A (en) * 1950-11-18 1957-03-26 Philips Corp Method of making supply cathodes and supply cathodes manufactured by means of these methods
US2721372A (en) * 1951-06-30 1955-10-25 Philips Corp Incandescible cathodes
US2750527A (en) * 1951-11-19 1956-06-12 Siemens Ag Cathode for electrical discharge device
US2848644A (en) * 1953-01-19 1958-08-19 Philips Corp Thermionic cathode
US2722626A (en) * 1953-02-16 1955-11-01 Philips Corp Thermionic cathode
US2902620A (en) * 1953-03-04 1959-09-01 Egyesuelt Izzolampa Supply cathode
US2786957A (en) * 1953-04-02 1957-03-26 Csf Emissive cathodes
DE1039140B (en) * 1953-04-02 1958-09-18 Csf Process for the production of supply cathodes
US2888592A (en) * 1954-07-22 1959-05-26 Gen Electric Cathode structure
US2928013A (en) * 1954-12-23 1960-03-08 Siemens Ag Electrical discharge device
US2931934A (en) * 1955-02-05 1960-04-05 Egyesuelt Izzolampa Indirectly heated supply cathode
US2822499A (en) * 1955-02-17 1958-02-04 Bell Telephone Labor Inc Cathodes for electron discharge devices
US3025428A (en) * 1959-10-15 1962-03-13 Kuthe Lab Inc Cathode structure
US3128531A (en) * 1959-10-22 1964-04-14 Nat Res Dev Dynodes for electron discharge tubes and methods of making same
US3842309A (en) * 1970-11-12 1974-10-15 Philips Corp Method of manufacturing a storage cathode and cathode manufactured by said method
US4229873A (en) * 1978-09-15 1980-10-28 Bykhovskij David G Method of producing nonconsumable electrode for use in arc techniques

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DE833089C (en) 1952-03-03

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