US3177393A - Cathode for an electric discharge tube - Google Patents

Cathode for an electric discharge tube Download PDF

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Publication number
US3177393A
US3177393A US132835A US13283561A US3177393A US 3177393 A US3177393 A US 3177393A US 132835 A US132835 A US 132835A US 13283561 A US13283561 A US 13283561A US 3177393 A US3177393 A US 3177393A
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US
United States
Prior art keywords
cathode
caps
discharge tube
electric discharge
wire
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
US132835A
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English (en)
Inventor
Gerlach Hans Georg
Jurgens Wilhelmus Albert
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.)
US Philips Corp
North American Philips Co Inc
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US Philips Corp
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
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3177393A publication Critical patent/US3177393A/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
    • 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
    • H01J1/15—Cathodes heated directly by an electric current
    • H01J1/18—Supports; Vibration-damping arrangements
    • 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
    • H01J1/15—Cathodes heated directly by an electric current
    • H01J1/16—Cathodes heated directly by an electric current characterised by the shape

Definitions

  • an electric discharge tube be ready for operation substantially immediately after potentials are applied thereto.
  • the transmitting tubes are switched off while receiving in order to reduce the filament current consumption, and switched on to transmit so that a quick heating cathode is desired.
  • the wires are connected to two parallel cross bars, these bars, during the construction of the system, must be connected to supporting members and tensioning springs. Since the thin wires have no stitfness and the cathode does not form a unit which can readily be handled, the mounting of the cathode in the electrode system is not simple.
  • Another object of our invention is to provide a cathode comprising a plurality of thin Wires which can be easily supported and mounted in an electric discharge tube.
  • the cathode in accordance with our invention comprises a plurality of fine wires wound on two U-shaped caps which are insulated from one another, which caps are slidable on two oppositely located ends of a supporting plate.
  • the supporting plate with the caps and the cathode wire form a unit which can be easily handled.
  • the covered cathode wire may then be wound on these caps in a simple manner, in which the emitting material of the parts which come into contact with the caps is removed by means of a scraper during winding, at least on that side of the wire which isto engage the U-shaped caps.
  • Supporting rods are provided on these caps for the mounting of the cathode unit in the electrode system.
  • the ends, on which the U-shaped caps have to slide have to be covered with an insulating layer; but this is not necessary if the supporting plate consists of insulating material.
  • FIG. 1 is a longitudinal sectional view of a cathode unit according to the invention
  • FIG. 2 is a side view of the embodiment shown in FIG. 1; 7
  • FIGS. 3 and 4 are a longitudinal sectional view and a side view respectively of another embodiment.
  • FIG. 5 is a longitudinal sectional view of still another embodiment according to the invention.
  • the emitting cathode wires 1 which may consist, for example, of a tungsten-thorium wire, or of a tungsten of molybdenum wire coated with a barium-strontium emission paste, is wound continuously on the U-shaped molybdenum caps 2 and 3.
  • the parts of the wire 1 which are to engage the caps 2 and 3 are made bare of emissive material by means of a scrapper (not shown), at least in those places which come into contact with the caps.
  • the caps 2 and 3 are supported in a slidable manner by the supporting plate 4 which in this case consists of ceramic material. Between the caps 2 and 3, respectively, and the supporting plate 4, the supporting rods 5 and 6, respectively, are provided and welded to the caps. Supporting wire 5 is afterwards mounted in the electrode system on a supporting rod while the supporting wire 6 is provided with a brace 7.
  • the cathode forms a unit which can be easily handled.
  • a cross brace 15 is provided on the brace 7 which is pulled downwards by springs 8 and consequently strains the wire 1 in that the caps 2 and 3 are slideable on the supporting plate 4.
  • the ceramic plate 4 in the embodiment shown in FIGS. 3 and 4 is replaced by a mica plate 11.
  • a mica plate is in addition less breakable than a ceramic plate.
  • the caps 2 and 3 are welded on metal cylinders 9 and 10 having a rectangular cross section, which support the mica plate 11 through the greater part of its length and can slide on it.
  • the tungsten cathode wire 1 which has a thickness of 27 microns and is coated with an emitting layer of 20 microns in thickness, is wound 20 times on the caps 2 and 3 so that the cathode consists entirely of 40 wire parts having a total surface area of 2 cm.
  • the total length of the cathode unit without the braces 5 and 6 is 38 mm.; the width of the caps 2 and 3 is 5 mm.; the wound width is 4 mm.
  • the wall thickness of the caps 2 and 3 is 0.25 mm., and that of the cylinders 9 and 10 is microns, and the thickness of the mica supporting plate is 0.4 mm.
  • the total thick ness of the cathode unit is 1.3 mm.
  • the current strength is 3 amp. at a filament voltage of 1.4 to 1.6 volts.
  • a supporting plate 12 consisting of metal, for example molybdenum, is used which is coated at the ends with insulating layers 13 and 14 so as to avoid a short-circuit of the caps 2 and 3.
  • This plate 12 may be coated with zirconium powder and then also operates as an ion trap if a relatively small negative voltage, i.e. 10 to 50 volts, is applied to it.
  • the cathode according to the invention very rapidly reaches the operating temperature owing to the use of thin wires and is highly suitable for transmitting tubes for very short waves, since the thin wires situated close to one another, emit as a surface, while the two cathode surfaces are separated by the supporting plate, so that a definite transit time is obtained. Since the electrons can travel from one cathode half to the associated half of the system only, all the electrons cover an equal distance. In addition, the inductance of the supply conductors and the cathode wires is small.
  • a directly heated cathode foran electric discharge tube comprising a support, a pair of U-shaped metal :caps insulated from one another slideably mounted on opposite ends of said support, and a plurality of paral- ;lel-connected thin Wires woundonsaid U-shaped metal caps. 7 a
  • a cathode for an electric discharge tube comprising a support, U-shaped metal caps insulated from one another and slideably mounted on said support, aplurality of parallel-connected thin wires wound on said metal caps, and resilient means engaging said caps for imparting tension to said wires mounted thereon.

Landscapes

  • Solid Thermionic Cathode (AREA)
  • Discharge Lamp (AREA)
  • Electron Sources, Ion Sources (AREA)
US132835A 1960-10-14 1961-08-21 Cathode for an electric discharge tube Expired - Lifetime US3177393A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL256883 1960-10-14

Publications (1)

Publication Number Publication Date
US3177393A true US3177393A (en) 1965-04-06

Family

ID=19752630

Family Applications (1)

Application Number Title Priority Date Filing Date
US132835A Expired - Lifetime US3177393A (en) 1960-10-14 1961-08-21 Cathode for an electric discharge tube

Country Status (6)

Country Link
US (1) US3177393A (enrdf_load_stackoverflow)
CH (1) CH404812A (enrdf_load_stackoverflow)
DE (1) DE1165758B (enrdf_load_stackoverflow)
ES (1) ES271131A1 (enrdf_load_stackoverflow)
GB (1) GB978217A (enrdf_load_stackoverflow)
NL (1) NL113253C (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3351793A (en) * 1964-10-28 1967-11-07 Licentia Gmbh Septum extraction electrode comprising a plurality of parallel wires under tension
US4143295A (en) * 1976-08-09 1979-03-06 Hitachi, Ltd. Cathode structure for an electron tube

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3312854A (en) 1964-07-31 1967-04-04 Philips Corp Cathode having a u-shaped support member
US3419743A (en) * 1965-12-15 1968-12-31 Rca Corp Electron tube having a tensioned cathode

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1273630A (en) * 1918-02-20 1918-07-23 Gen Electric Electron-discharge apparatus.

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE519082C (de) * 1926-04-21 1931-02-23 Radiotechnique Soc Verfahren zur Herstellung von Elektronenroehren

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1273630A (en) * 1918-02-20 1918-07-23 Gen Electric Electron-discharge apparatus.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3351793A (en) * 1964-10-28 1967-11-07 Licentia Gmbh Septum extraction electrode comprising a plurality of parallel wires under tension
US4143295A (en) * 1976-08-09 1979-03-06 Hitachi, Ltd. Cathode structure for an electron tube

Also Published As

Publication number Publication date
DE1165758B (de) 1964-03-19
GB978217A (en) 1964-12-16
CH404812A (de) 1965-12-31
NL113253C (enrdf_load_stackoverflow)
ES271131A1 (es) 1962-01-01

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