US2421039A - Cathode structure - Google Patents

Cathode structure Download PDF

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Publication number
US2421039A
US2421039A US520383A US52038344A US2421039A US 2421039 A US2421039 A US 2421039A US 520383 A US520383 A US 520383A US 52038344 A US52038344 A US 52038344A US 2421039 A US2421039 A US 2421039A
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US
United States
Prior art keywords
metal
disk
cathode
insulating
plate
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
US520383A
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English (en)
Inventor
Jr Carl A Segerstrom
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.)
STC PLC
Federal Telephone and Radio Corp
Original Assignee
Standard Telephone and Cables PLC
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 BE470922D priority Critical patent/BE470922A/xx
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US520383A priority patent/US2421039A/en
Priority to GB2090/45A priority patent/GB590520A/en
Priority to CH259587D priority patent/CH259587A/de
Priority to FR928312D priority patent/FR928312A/fr
Application granted granted Critical
Publication of US2421039A publication Critical patent/US2421039A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J21/00—Vacuum tubes
    • H01J21/36—Tubes with flat electrodes, e.g. disc electrode
    • 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

Definitions

  • This invention relates to improvements in cathode structures, and more particularly to indirectly heated cathodes adapted for use in electron discharge devices.
  • An object of the present invention is to provide an indirectly heated cathode structure of improved efliciency.
  • Another object of this invention is to provide an indirectly heated cathode structure in which the heating element concentrates its heat toward the electron-emitting cathode with a minimum of loss.
  • Still another object of this invention is the provision of an improved heater structure, especially for cathodes of electron discharge devices.
  • a further object of this invention is to provide an improved cathode structure in which the electron emitting surface is indirectly heated by direct radiation and concentrated reflected heat from an adjacent heating element.
  • Fig. 1 is a vertical cross-sectional view in partial perspective of a vacuum tube illustrating one form of cathode structure in accordance with the present invention
  • Fig. 2 is an enlarged top plan view of the cathode heater structure shown in Fig. 1;
  • Fig. 3 is a partial enlarged cross-sectional view of a detail of the cathode structure
  • Fig. 4 is a top plan view of a modified form of cathode heater structure according to the present invention.
  • Fig. 5 is a transverse cross-sectional view taken along the line 5-5 of Fig. 4;
  • Fig. 6 is a top plan view of a still further form of cathode heater structure according to the present invention.
  • Fig. '7 is a transverse cross-sectional view taken along the line 'i'
  • Fig. 1 illustrates a preferred form of cathode structure according to the present invention, illustrated, by way of example, as used in one type of high frequency electron-discharge device which is more fully described and claimed in my copending application, S. N. 517,498, filed January 8, 1944, now Patent No. 2,391,927.
  • This tube may be built up on a, metal base ID in the form of a disk having an opening in its center.
  • a second metal disk l2 also having an opening in its center is spaced from a disk ID by means of a glass annulus I4 sealed to suitable extensions on the two disks.
  • a third disk 16 also having a hole in its center is spaced from and supported by the disk l2 by a second glass annulus i8 sealed to extensions on these two disks in a manner known to the art.
  • a grid 20 about the central opening in the disk l2 may be placed a grid 20, while over the central opening of the disk i6 is placed a hollow metal cylinder 22 having a closed cylindrical extension 24 passing through the opening, the bottom of this extension being spaced adjacent to the grid 20 and forming the tube anode.
  • the main part of the cylinder 22 is sealed to the outer surface of the disk It and it will be seen that this cylinder, together with the disk I8, the glass portion 18, the width of the disk [2 and the glass portion l4 form part of the vacuum tube envelope.
  • a cathode in accordance with the present invention in the form of a metal disk 26 coated with some suitable emissive material and resting on a ceramic or other insulating plate 28.
  • This plate may have imbedded in it a pair of heater coils 30 and 32, spirally interwound, as more clearly indicated in Fig. 2.
  • a lead 34 may be connected to the outer end of the coil 30.
  • a common lead 38 to the center common point of the two heater wires, and a further lead 42 to the outer end of the heater coil 32.
  • the leads 34 and 38 pass through an insulating support 44 sealed within the central opening of the base disk I0 and serve, at the same time, to support the ceramic plate 28 and its superimposed cathode disk 25 in proper spaced relation with the grid 20.
  • Other wires such as 36 may be used to give additional support but they need not pass through the insulating base 44.
  • still another lead wire 40 passing through the insulating base 44 may pass upwardly through the ceramic plate 28 and make contact with the metal disk 26 to afford a D. C. cathode lead.
  • the two outer ends of the heater wires 30 and 32 may be interconnected by any suitable means such as a. transverse lead wire 46, which then effectively connects the two heater filaments in parallel.
  • the metal disk 26 is preferably supported out of contact with the heater wires, as by the annular ring 56 on the upper surface of the ceramic plate, and may be attached to this rim in any suitable manner (not shown).
  • a cylinder 48 of some suitable metal foil which, if the device is to be used with high or ultra high frequencies, may be spaced from a, flanged metal sleeve 50 by a cylinder 52 of mica or other insulating material.
  • flanged portion or the sleeve Ill may be welded or otherwise attached to the metal base III. the aforedescribed construction thus forming between the cathode 26 and this metal base a series condenser structure.
  • Means such as a spring ring 54 may be used to press the foil 48 against the insulating sleeve and the attached metal sleeve.
  • the cathode structure described above is relatively simple of manufacture, compact and is most efllcient.
  • the use of metal foil 48 provides a simple built-in condenser structure, and at the'same time this metal foil will conduct little heat away from the cathode disk 26.
  • the heater structure may be most advantageously utilized if the heater coils 30 and 32, as more clearly shown in Fig. 2, are wound with a closer spacing near the periphery of the cathode disk where heat losses may be greater, than near the center. If the internal condenser structure between the cathode and outer disk in is not desired, the metal foil 48 will be readily galvanically connected thereto, as will be obvious to those skilled in this art.
  • a plate I28 of ceramic or other insulating material has, in addition to an integral surrounding raised ring I56, a plurality of integral, radiallyextending ribs l 58 provided with radially spaced, generally arcuate notches I60 which hold and support the heater coils 30, 32 on the surface or the plate.
  • the surface of the plate may, inturn, be coated with some suitable heatreflecting material, for example, magnesium oxide. The heat from the heater coils is thus even more concentrated toward'the cathode disk which will be supported upon the upper surface of the surrounding, integral ring I56.
  • Heater leads 34, 38 and 42 will be provided as before,
  • the heater structure illustrated in Figs. 6 and 7 is similar to that shown in Figs. 4 and 5 except that in this case the heater coils I0 and 32 are supported above a heat-reflecting surface I62 by a plurality of pigtails 284, each having one end wrapped about or otherwise attached to a point on one of the heater coils, and having its other end passing into, and imbedded in the supporting insulating plate.
  • the cathode disk is supported on the ring 56, as before, while the same lead construction which supports the insulating plate 28 from the insulating base may be utilized.
  • the heater structures may be of use other than as heater elements for the cathodes of electron discharge devices, and as far as the instant invention is concerned it is not intended to limit the heater structures shown solely for use in connection with such cathodes.
  • I have utilized the double spiral heater construction with variable spacing, as illustrated in Fig. 1, although it will be clear that a single heater coil with other spacing could be utilized, if desired. Accordingly, while I have described above the principles of my invention in connection with speciiic apparatus, and particular modifications thereof. it is to be clearly understood that this description is made only by way of example, and
  • Cathode structure comprising, an insulating plate having an integral upstanding ring on one surface thereof, heating coils carried by said plate, a metal disk carried on said ring out of contact with said heating coils, an insulating base, and means including lead wires attached to said heating coils and metal disk at one end and passing through said insulating base near their other ends, supporting said insulating plate in spaced relation with said insulating base.
  • heating coils are in the form of a pair of interwound spirals connected together at their center, the spacing between adjacent turns of the two coils being closer near the outer portion of the insulating plate than at the inner portion thereof.
  • Cathode structure comprising an insulating plate having an integral upstanding ring on one surface thereof, and integral grooved supports below the upper surface of said ring, heating coils carried by said plate in said grooves, a metal disk carried on said ring out of contact with said heating coils, an insulating base, and means including lead wires attached to said heating coils and metal disk at one end and passing through said insulating base near their other ends, supporting said insulating plate in spaced relation with said insulating base.
  • saidheatlng coils are in the form of a pair of interwound spirals connected together at their center, the spacing between adjacent turns of heating coil on said plate above said reflecting means but below the upper surface of said ring, a metal disk carried on said ring out of contact with said heating coil, an insulating base, and means including lead wires attached to said heating coil and metal disk at one end and passing through said insulating base near their other ends, supporting said insulating plate in spaced relation-with said insulating base.
  • heating coil is in the form of a pair of interwound spirals connected together at their center, the spacing between adjacent turns of the two spirals being closer near the outer portion of the insulating plate than at the inner portion thereof.
  • Cathode structure comprising an insulating plate having an integral upstanding ring on one surface thereof, and a plurality of integral, angularly-spaced ribs extending inwardly from said ring toward the center of said plate, each of said ribs being provided with a plurality of radially spaced, generally arcuategrooves.
  • a spiral heating coil carried by said groove above the surface of the plate, heat-reflecting means on said surface, a metal disk carried on said ring, an insulating base, and means including lead wires attached to said heating coil and metal disk at one end and passing through said insulating base near their other ends, supporting said insulating plate in spaced relation with said insulating base.
  • heating coil is in the form of a pair of interwound spirals connected together at their center. the spacing between adjacent turns of the two spirals being closer near the outer portion of the insulating plate than at the inner portion thereof.
  • Cathode structure comprising an insulating plate having an integral upstanding ring on one surface thereof, heat-reflecting means covering said surface, a heating coil, means supporting said heating coil above said reflecting surface and below the upper surface of said ring, said means including a plurality of spaced, fine wire pigtails, each having one end wrapped about spaced points on said heating coil and its other end imbedded in said insulating plate, a metal disk carried on said ring out of contact with said heating coil, an insulating base, and means including lead Wires attached to said heating coil and metal disk on one end and passing through said insulating base near their other ends, supporting said insulating plate in spaced relation with said insulating base.
  • heating coil is in the form of a pair of interwound spirals connected together at their center, the spacing between adjacent turns of the two spirals being closer near the outer portion of the insulating plate than at the inner portion thereof.
  • Cathode structure comprising a, flat wound wire heating element and a metallic plate coated with emitting materials in close spaced parallel relation with said element, the wire of said element towards the perimeter thereof being spaced more closely together than towards the center thereof.
  • a unitary condenser and cathode assembly comprising a metal plate, said plate being electron emissive on one side, and a heating element adjacent the other side of said plate;
  • the condenser comprising two coaxial insulatingly spaced metal cylinders capacitively coupled, the rim of one cylinder being electrically connected along the periphery of said plate. and an electrical connection to the rim of the other cylinder.
  • a cathode assembly comprising a sheet metal member electron emissive on one side, a heating element ad- 'jacent the other side of the member, two coaxial metal cylinders and a cylinder of insulating material, the cylinder of insulating material being telescoped between the two metal cylinders, the rim of one of said metal cylindersbeing directly connected to the edge of said member.

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  • Electrodes For Cathode-Ray Tubes (AREA)
  • Solid Thermionic Cathode (AREA)
US520383A 1944-01-31 1944-01-31 Cathode structure Expired - Lifetime US2421039A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE470922D BE470922A (fr) 1944-01-31
US520383A US2421039A (en) 1944-01-31 1944-01-31 Cathode structure
GB2090/45A GB590520A (en) 1944-01-31 1945-01-26 Indirectly-heated cathode structures for electron discharge devices
CH259587D CH259587A (de) 1944-01-31 1945-11-08 Elektrische Heizvorrichtung, insbesondere für eine indirekt geheizte Kathode.
FR928312D FR928312A (fr) 1944-01-31 1946-01-12 Cathodes pour tubes électroniques

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US520383A US2421039A (en) 1944-01-31 1944-01-31 Cathode structure

Publications (1)

Publication Number Publication Date
US2421039A true US2421039A (en) 1947-05-27

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ID=24072365

Family Applications (1)

Application Number Title Priority Date Filing Date
US520383A Expired - Lifetime US2421039A (en) 1944-01-31 1944-01-31 Cathode structure

Country Status (5)

Country Link
US (1) US2421039A (fr)
BE (1) BE470922A (fr)
CH (1) CH259587A (fr)
FR (1) FR928312A (fr)
GB (1) GB590520A (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2436907A (en) * 1945-06-23 1948-03-02 Nasa Indirectly heated cathode
US2500355A (en) * 1944-11-14 1950-03-14 Sylvania Electric Prod Electron discharge tube
US2504335A (en) * 1946-08-30 1950-04-18 Hartford Nat Bank & Trust Co Indirectly heated cathode
US2899591A (en) * 1959-08-11 Electrical heating device
DE1133041B (de) * 1954-10-22 1962-07-12 Gen Electric Verfahren zur Herstellung eines aus einer duennen Folie bestehenden Heizers oder Kathodenkoerpers fuer eine mit Hochfrequenz geheizte Roehre und der nach dem Verfahren hergestellte Heizer oder Kathodenkoerper
DE1143589B (de) * 1959-12-22 1963-02-14 Edgerton Germeshausen And Grie Verfahren zur Herstellung eines Heizers fuer Kathoden von elektrischen Entladungsroehren
US3558965A (en) * 1967-10-02 1971-01-26 Nat Video Corp Cathode for television tube and method of making
US4878866A (en) * 1986-07-14 1989-11-07 Denki Kagaku Kogyo Kabushiki Kaisha Thermionic cathode structure

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4296311A (en) * 1979-08-15 1981-10-20 The Kanthal Corporation Electric hot plate

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1102249A (en) * 1911-10-31 1914-07-07 Cutler Hammer Mfg Co Electric resistance unit.
US1539497A (en) * 1922-03-27 1925-05-26 W B Mcallister Company Electrical heating device
FR700923A (fr) * 1929-11-13 1931-03-09 Telefunken Gmbh Tube à cathode chauffée et électrode de commande
US1866195A (en) * 1929-06-01 1932-07-05 Ile De France Radio valves employing gallium
US2051637A (en) * 1934-12-07 1936-08-18 Electric Trading Corp Electrical heating device
US2300891A (en) * 1941-04-25 1942-11-03 Hankscraft Co Liquid conductor heater
US2357905A (en) * 1942-01-26 1944-09-12 Mcgraw Electric Co Automatic sadiron
US2367332A (en) * 1942-06-26 1945-01-16 Gen Electric Cathode

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1102249A (en) * 1911-10-31 1914-07-07 Cutler Hammer Mfg Co Electric resistance unit.
US1539497A (en) * 1922-03-27 1925-05-26 W B Mcallister Company Electrical heating device
US1866195A (en) * 1929-06-01 1932-07-05 Ile De France Radio valves employing gallium
FR700923A (fr) * 1929-11-13 1931-03-09 Telefunken Gmbh Tube à cathode chauffée et électrode de commande
US2051637A (en) * 1934-12-07 1936-08-18 Electric Trading Corp Electrical heating device
US2300891A (en) * 1941-04-25 1942-11-03 Hankscraft Co Liquid conductor heater
US2357905A (en) * 1942-01-26 1944-09-12 Mcgraw Electric Co Automatic sadiron
US2367332A (en) * 1942-06-26 1945-01-16 Gen Electric Cathode

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2899591A (en) * 1959-08-11 Electrical heating device
US2500355A (en) * 1944-11-14 1950-03-14 Sylvania Electric Prod Electron discharge tube
US2436907A (en) * 1945-06-23 1948-03-02 Nasa Indirectly heated cathode
US2504335A (en) * 1946-08-30 1950-04-18 Hartford Nat Bank & Trust Co Indirectly heated cathode
DE1133041B (de) * 1954-10-22 1962-07-12 Gen Electric Verfahren zur Herstellung eines aus einer duennen Folie bestehenden Heizers oder Kathodenkoerpers fuer eine mit Hochfrequenz geheizte Roehre und der nach dem Verfahren hergestellte Heizer oder Kathodenkoerper
DE1143589B (de) * 1959-12-22 1963-02-14 Edgerton Germeshausen And Grie Verfahren zur Herstellung eines Heizers fuer Kathoden von elektrischen Entladungsroehren
US3558965A (en) * 1967-10-02 1971-01-26 Nat Video Corp Cathode for television tube and method of making
US4878866A (en) * 1986-07-14 1989-11-07 Denki Kagaku Kogyo Kabushiki Kaisha Thermionic cathode structure

Also Published As

Publication number Publication date
CH259587A (de) 1949-01-31
GB590520A (en) 1947-07-21
BE470922A (fr)
FR928312A (fr) 1947-11-25

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