US3688151A - Device having an electric discharge tube comprising a field emission cathode, and discharge tube destined for such a device - Google Patents

Device having an electric discharge tube comprising a field emission cathode, and discharge tube destined for such a device Download PDF

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Publication number
US3688151A
US3688151A US71806A US3688151DA US3688151A US 3688151 A US3688151 A US 3688151A US 71806 A US71806 A US 71806A US 3688151D A US3688151D A US 3688151DA US 3688151 A US3688151 A US 3688151A
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United States
Prior art keywords
aluminum oxide
layer
discharge tube
aluminum
cathode
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Expired - Lifetime
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US71806A
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English (en)
Inventor
Constant Gijsbertus Joh Jansen
Klaas Compaan
Albertus Venema
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US Philips Corp
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US Philips Corp
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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
    • H01J1/30—Cold cathodes, e.g. field-emissive cathode
    • H01J1/304—Field-emissive cathodes

Definitions

  • the invention relates to a device having an electric discharge tube comprising a field emission cathode consisting of a layer of aluminum oxide on which a conductive metal layer is present on one side and a metal grid which has a positive potential relative to the conductive metal layer is present on the other side.
  • the invention furthermore relates to an electric discharge tube destined for such a device.
  • the aluminum oxide in the cathode described in the German patent specification 746,016 consists of a comparatively thick sintered mass.
  • the metal layer is provided on the aluminum oxide as a metallization
  • the metal grid is preferably pressed in the aluminum oxide layer.
  • the emission current is assumed to consist of electrons which move from the interior of the aluminum oxide to the apertures in the metal grid and there either emanate themselves, or liberate secondary electrons from the edges of the grid. Once the emission has started, it is not necessary to apply an external potential difference between the two electrodes at the aluminum oxide, since as a result of the emission the potential difference is automatically maintained. However, this applies only if the cathode goes on supplying current. In so far as it is known, the cathode described has not resulted in practical applications and data on the emission density to be achieved with the cathode and the value of the applied voltages are not known either.
  • a cold cathode which consists of an aluminum plate on which a layer of aluminum oxide with a thickness of from 100 to 300 AU is formed by vapor-deposition or by anodic oxidition. On this layer is present a layer of a metal, such as gold, platinum or palladium, obtained by vapor-deposition, which layer in turn is covered with a thick porous layer of magnesium oxide which has likewise been obtained by vapor-deposition. The thickness of this layer is in the order of 50 pm.
  • the cathode requires a voltage of approximately volts across the layer of aluminum oxide.
  • the aluminum oxide layer consists of a porous oxide layer having a thickness of from a few pm to a few tens um formed on an aluminum support by anodic oxidation.
  • Such porous aluminum oxide layers which have long been known already (see A.J. Decker and W.Ch. van Geel, Philips Res. 2 313-319, 1947) have a substantially hexagonal structure in which cavities and pillarlike particles of aluminum oxide, both with a diameter of a few hundred of AU directed at right angles to the surface, seem to alternate.
  • the cavities and pillars of oxide are separated from the underlying aluminum by a closed layer of aluminum oxide the thickness of which expressed in tens of AU is approximately equal to the voltage expressed in volts applied in the electrolytic formation of the layer.
  • As an electrolyte in the formation of the layer is used oxalic acid or another acid in which exclusively the formation of aluminum oxide occurs.
  • the required potential difference across the layer is in the order of 50 volts or higher.
  • the metal grid has a sufficiently low thickness, wire thickness 50 um and less, the gauze is attracted, throughout the surface of the cathode, by the electrostatic force.
  • the advantage of this with respect to a more rigid grid of thicker wires which is held only by mechanical force is that it better engages the surface of the cathode, which promotes the uniformity of the emission across the surface.
  • FIG. I is a diagrammatic representation on a strongly exaggerated scale of the electrode system of an electric discharge tube according to the invention with the associated electric connections and FIG. 2 shows a few current-voltage characteristics.
  • Reference numeral 1 in FIG. 1 denotes a strip of aluminum which has been bent at right angles and has an upper surface area of 0.3 sq.cm.
  • a porous oxide layer 2 thickness 5 pm, in which cavities are present at right angles to the surface, is present on the aluminum, the cavities and the intermediate oxide having transverse dimensions of from 200 to 500 AU.
  • Below said layer is a thin layer of aluminum oxide having a thickness of approximately AU.
  • a copper gauze 3, mesh width 40 um, wire thickness 7 pm, is present on the aluminum oxide 2.
  • the anode is constituted by a nickel plate 4 at a distance of 2 mm from the gauze 3.
  • the electric connection of the aluminum plate, the gauze and the nickel anode are denoted by 5, 6 and 7.
  • the current limiting resistors 8 and 9, respectively, each 1 Mil, are included in the connection leads to 5 and 7.
  • FIG. 2 the voltage difference between the connection terminals 6 and '7 in volts is plotted on the horizontal axis, and the electron current in A which flows to the anode 4 is plotted on the vertical axis, curve A applying to the case in which the voltage between 5 and 6 is volts and curve B applying to the case in which said voltage is volts.
  • the currents in said circuit are 2.0 and 12.5 A respectively.
  • a device having an electric discharge tube comprising a field emission cathode consisting of a layer of aluminum oxide on which a conductive metal layer is present on one side and on which a metal grid which has a positive potential relative to the conductive metal layer is present on the other side, said aluminum oxide layer consisting of a porous oxide layer formed on an aluminum support by anodic oxidation.

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  • Photoreceptors In Electrophotography (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Cold Cathode And The Manufacture (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
US71806A 1969-09-18 1970-09-14 Device having an electric discharge tube comprising a field emission cathode, and discharge tube destined for such a device Expired - Lifetime US3688151A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6914205A NL6914205A (enrdf_load_stackoverflow) 1969-09-18 1969-09-18

Publications (1)

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US3688151A true US3688151A (en) 1972-08-29

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ID=19807934

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US71806A Expired - Lifetime US3688151A (en) 1969-09-18 1970-09-14 Device having an electric discharge tube comprising a field emission cathode, and discharge tube destined for such a device

Country Status (5)

Country Link
US (1) US3688151A (enrdf_load_stackoverflow)
DE (1) DE2044466A1 (enrdf_load_stackoverflow)
FR (1) FR2062284A5 (enrdf_load_stackoverflow)
GB (1) GB1267029A (enrdf_load_stackoverflow)
NL (1) NL6914205A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4317067A (en) * 1980-04-11 1982-02-23 Fitzsimmons William A Dielectric surface electrical discharge device
US5945790A (en) * 1997-11-17 1999-08-31 Schaefer; Raymond B. Surface discharge lamp

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE39633E1 (en) 1987-07-15 2007-05-15 Canon Kabushiki Kaisha Display device with electron-emitting device with electron-emitting region insulated from electrodes
USRE40062E1 (en) 1987-07-15 2008-02-12 Canon Kabushiki Kaisha Display device with electron-emitting device with electron-emitting region insulated from electrodes
US5066883A (en) * 1987-07-15 1991-11-19 Canon Kabushiki Kaisha Electron-emitting device with electron-emitting region insulated from electrodes
US5872541A (en) * 1987-07-15 1999-02-16 Canon Kabushiki Kaisha Method for displaying images with electron emitting device
USRE40566E1 (en) 1987-07-15 2008-11-11 Canon Kabushiki Kaisha Flat panel display including electron emitting device
GB8816689D0 (en) * 1988-07-13 1988-08-17 Emi Plc Thorn Method of manufacturing cold cathode field emission device & field emission device manufactured by method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1618499A (en) * 1923-11-06 1927-02-22 Charles P White Electrical apparatus
DE746016C (de) * 1938-05-09 1953-02-09 Siemens & Halske A G Berlin Un Kalte Kathode fuer elektrische Entladungsroehren
FR1359344A (fr) * 1963-03-15 1964-04-24 Csf Perfectionnements aux cathodes froides à couche diélectrique
US3154711A (en) * 1961-06-19 1964-10-27 Gen Electric Electron beam focusing by means of contact differences of potential
US3363136A (en) * 1966-03-22 1968-01-09 Rauland Corp Thermionic cathodes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1618499A (en) * 1923-11-06 1927-02-22 Charles P White Electrical apparatus
DE746016C (de) * 1938-05-09 1953-02-09 Siemens & Halske A G Berlin Un Kalte Kathode fuer elektrische Entladungsroehren
US3154711A (en) * 1961-06-19 1964-10-27 Gen Electric Electron beam focusing by means of contact differences of potential
FR1359344A (fr) * 1963-03-15 1964-04-24 Csf Perfectionnements aux cathodes froides à couche diélectrique
US3363136A (en) * 1966-03-22 1968-01-09 Rauland Corp Thermionic cathodes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4317067A (en) * 1980-04-11 1982-02-23 Fitzsimmons William A Dielectric surface electrical discharge device
US5945790A (en) * 1997-11-17 1999-08-31 Schaefer; Raymond B. Surface discharge lamp

Also Published As

Publication number Publication date
DE2044466A1 (de) 1971-04-01
FR2062284A5 (enrdf_load_stackoverflow) 1971-06-25
GB1267029A (enrdf_load_stackoverflow) 1972-03-15
NL6914205A (enrdf_load_stackoverflow) 1971-03-22

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