US2486292A - Cathode structure for electric discharge tubes - Google Patents

Cathode structure for electric discharge tubes Download PDF

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Publication number
US2486292A
US2486292A US685157A US68515746A US2486292A US 2486292 A US2486292 A US 2486292A US 685157 A US685157 A US 685157A US 68515746 A US68515746 A US 68515746A US 2486292 A US2486292 A US 2486292A
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United States
Prior art keywords
cathode
layer
electric discharge
conductive
discharge tubes
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Expired - Lifetime
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US685157A
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English (en)
Inventor
Jonker Johan Lodewijk Hendrik
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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Publication date
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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

Definitions

  • This invention relates toan electric discharge tube and particularly to the cathode of such a tube.
  • the thickness of the emitting layer of a cathode for ⁇ discharge tubes, particularly rectifier and amplier valves, should be a minimum in order to ensure a low resistance across the layer and in addition satisfactory adherence of this layer to the support.
  • a very thin emitting layer may, however, have the disadvantage that the quantity of the emitting substance is low so that the cathode has a W life.
  • cathodes with a large supply of emitting material by housing this material in a small thin-walled tube which is heated direct and in which the active metal is outwardly diffused through the wall of this tube; While the cathode is in use; such a cathode acts as though it comprises a thin emitting layer, whilst at the same time a large supply of emitting material is internally available for subsequent supply. This subsequent supply, however, proceeds comparatively slowly so that nevertheless fatigue phenomena may occur.
  • the lm on the emitting material must have connected to it a current conductor; in this case it is 4not essential that such a conductor should also be connected to the conductive support of the emitting layer but particular advantages may be secured thereby.
  • the resistance across the layer and thus the subsequent supply and the emission may be favourably inuenced if a low potential difference is applied between the two conductors.
  • This potential diierence is for example lower than l0 volts and at any rate lower than volts of direct tension. This tension results in a certain electrolysis of the emissive oxides and this assists in the subsequent supply of emissive substance to the surface of the external layer.
  • the support may be constituted by nickel, copper, tungsten, molybdenum or similar metals and the emissive layer by one or more alkaline earth oxides.
  • the external layer applied to this emissive layer may also be constituted by a metal such as nickel and may be of widely different form and structure.
  • this layer is, however, constituted by a nickel wire gauze which is applied to the emissive layer; a further embodiment consists for example in a wire which is wound around the cathode in the form of a spiral or of a helix.
  • I designates a heating element which by means of insulating material may be separated from the support 2 for the emissive layer 3; this emissive layer 3 has applied to it a conductive lm 4 constituted by a nickel wire gauze folded and welded around the cathode.
  • the cathode thus constructed is surrounded by a grid 5 and an anode 6; the electrodes are centered by means of mica discs 'I and 8.
  • the aggregate is housed in a bulb 9 sealed by a disc I0.
  • This disc has sealed in it the contact members II of the tube and these contact members are connected on the inside of the tube to the various current supply conductors of the electrodes, to Wit the conductor I2 for the anode, the conductor I3 ⁇ for the grid, the conductors I4 for the heating element and finally the conductors l5 and I6 which are connected respectively to the support of the emitting material and the conductive lm on the emitting material; the corresponding connecting conductors of the tube may have the desired potential difference applied between them.
  • An electric discharge device comprising an anode and an indirectly heated cathode, said cathode embodying a heater, a conductive support adjacent to the heater, but electrically insulated therefrom, a layer of a readily emitting substance on the support, a conductive coating on said substance, a current supply conductor connected to said conductive coating and having a terminal for connection to an external circuit, and a separate supply conductor connected to the conductive support for the cathode and having a terminal for connection to an external circuit.
  • An electric discharge device comprising an anode and an indirectly heated cathode, said cathode embodying a centrally located heater, a cylindrical conductive support about said heater, but electrically insulated therefrom, a layer of a readily emitting substance on the support, a conductive coating of metal wire gauze about said substance, a current supply conductor connected to said conductive coating and having a terminal for connection to an external circuit, and a separate supply conductor connected to the conductive support for the cathode and having a terminal for connection to an external circuit, whereby a potential difference may be applied between the conductive support and the conductive coating on the emissive material.

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  • Discharge Lamp (AREA)
  • Solid Thermionic Cathode (AREA)
US685157A 1943-12-31 1946-07-20 Cathode structure for electric discharge tubes Expired - Lifetime US2486292A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL630621X 1943-12-31

Publications (1)

Publication Number Publication Date
US2486292A true US2486292A (en) 1949-10-25

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ID=19788726

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US685157A Expired - Lifetime US2486292A (en) 1943-12-31 1946-07-20 Cathode structure for electric discharge tubes

Country Status (3)

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US (1) US2486292A (fr)
FR (1) FR915556A (fr)
GB (1) GB630621A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563573A (en) * 1951-08-07 Hot cathode electron tube which re

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1923335A (en) * 1931-09-23 1933-08-22 Raytheon Inc Thermionic vapor discharge device
US1936419A (en) * 1930-06-03 1933-11-21 Gen Electric Photo-electric tube
US2091554A (en) * 1935-10-03 1937-08-31 Bell Telephone Labor Inc Composite refractory body
US2107945A (en) * 1934-11-20 1938-02-08 Gen Electric Cathode structure
US2128051A (en) * 1935-10-03 1938-08-23 Westinghouse Electric & Mfg Co Electric discharge apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1936419A (en) * 1930-06-03 1933-11-21 Gen Electric Photo-electric tube
US1923335A (en) * 1931-09-23 1933-08-22 Raytheon Inc Thermionic vapor discharge device
US2107945A (en) * 1934-11-20 1938-02-08 Gen Electric Cathode structure
US2091554A (en) * 1935-10-03 1937-08-31 Bell Telephone Labor Inc Composite refractory body
US2128051A (en) * 1935-10-03 1938-08-23 Westinghouse Electric & Mfg Co Electric discharge apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2563573A (en) * 1951-08-07 Hot cathode electron tube which re

Also Published As

Publication number Publication date
FR915556A (fr) 1946-11-12
GB630621A (en) 1949-10-18

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