US3761761A - Device comprising an electric high vacuum discharge tube provided with at least two electrodes not destined for emission, and discharge tube for such a device - Google Patents

Device comprising an electric high vacuum discharge tube provided with at least two electrodes not destined for emission, and discharge tube for such a device Download PDF

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Publication number
US3761761A
US3761761A US00154348A US3761761DA US3761761A US 3761761 A US3761761 A US 3761761A US 00154348 A US00154348 A US 00154348A US 3761761D A US3761761D A US 3761761DA US 3761761 A US3761761 A US 3761761A
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United States
Prior art keywords
electrodes
discharge tube
emission
titanium
high vacuum
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Expired - Lifetime
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US00154348A
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English (en)
Inventor
Oostrom A Van
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US Philips Corp
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US Philips Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/02—Vessels; Containers; Shields associated therewith; Vacuum locks
    • H01J5/06—Vessels or containers specially adapted for operation at high tension, e.g. by improved potential distribution over surface of vessel
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0001—Electrodes and electrode systems suitable for discharge tubes or lamps
    • H01J2893/0012—Constructional arrangements
    • H01J2893/0019—Chemical composition and manufacture
    • H01J2893/0022—Manufacture
    • H01J2893/0023—Manufacture carbonising and other surface treatments

Definitions

  • the invention relates to a device comprising an electric high vacuum discharge tube provided with at least two non-emitting electrodes, between which during operation of the device a high field strength prevails as a result of a voltage difference, direct voltage or low frequency voltage present between said electrodes.
  • High electric field strength is to be understood to mean in this connection a macroscopic field strength of more than kvolt/cm resulting from an applied direct voltage difference or a low frequency alternating voltage difference.
  • the macroscopic field strength follows from the applied voltage difference and the geometry of the arrangement without taking surface structure into account.
  • the invention also relates to a device having vacuum switches in which, in addition to contacts, screen electrodes are present.
  • One of the causes by which a breakdown can be introduced in a vacuum is the detachment of microparticles of electrodes or enveloping tube wall under the infiuence of a strong electric field. This cause can be substantially eliminated by careful processing during the manufacture of electrodes and other components as well as their assembly with regard to the absence of dust and smoothly finished surfaces. Moreover, during the actuation of the device, the voltage between the electrodes is increased gradually to restrict the occurrence of discharges if any in intensity.
  • the result of said protrusions is that at the free extremity thereof, and also in connection with the small radii of curvature, the field strength is considerably higher than the macroscopic field strength.
  • the field intensification factor i.e. the ratio of the actual field strength to the point of the protrusions to the macroscopic field strength, for example, is for copper in a quite clean condition and a good vacuum, approximately 100. In the presence of contaminations and in poor vacuum conditions, the field intensification factor may increase to a few hundreds and even above thousand. Under the influence of the high field strengths, field emission occurs from the protrusions.
  • this field emission results in a temperature increase of one of the electrodes, the negative or the positive one, which locally is so high that the formation of vapour occurs.
  • the ionization formed in said vapour results in breakdown.
  • the electrodes consist of copper having a closed layer of titanium or zirconium in a thickness of from 10 to 50 AU on at least those parts where a high field strength occurs.
  • the admissible field strength can amount to 20 kvolt/mm and more, as a result of which inter alia more compact constructions are possible.
  • the invention is based on the recognition of the fact that in the protrusions formed from copper the temperature increase as a result of the field emission current (Joule heat) is as small as possible, because both the electric and the thermal conductivity of copper are high.
  • the vapour pressure is lower than of copper while the thin titanium layer or zirconium layer has no influence on the electric and thermal conductivity. Gases, if any, released by the heating are also readily gettered, at least in none too large quantities. Similar considerations hold good for the positive electrode.
  • said layer is preferably provided by vapour deposition.
  • FIG. 1 shows a measuring arrangement
  • FIG. 2 shows diagrammatically a part of an electron microscope.
  • FIG. 3 is a cross-sectional view through an X-ray tube
  • FIG. 4 is a cross-sectional view through the electron gun of a display tube
  • FIG. 5 is a cross-sectional view through a vacuum switch.
  • two copper electrodes 2 and 3 covered with a layer of titanium 4 and 5, respectively, are present inside the glass tube 1.
  • the diameter of the electrodes is 18 mm and the mutual distance is 0.25mm.
  • the thickness of the titanium layers is 40 AU.
  • the current with a voltage difference of 5 kVolt between the electrodes was less than A. This high insulation value was maintained for several weeks.
  • reference numeral 20 denotes the V- shaped thermionic cathode of an electron microscope
  • 21 is the grid and 22 the accelerating anode.
  • the object is denoted by 23 and the fluorescent screen by 24.
  • a number of electromagnetic lenses is denoted by 25 to 28.
  • the grid 21 and the anode 22 are coated on the sides facing each other with a layer of zirconium 29 of 30 AU denoted in broken lines. With a distance of 5 mm between 21 and 22, the voltage difference may be more than 125 k.volt.
  • the X-ray tube shown in FIG. 3 consists of a glass envelope 30 in which is arranged a cathode 31, surrounded by a cathode screen 32.
  • a soft magnetic anode tube 33 is sealed to the glass by means of a wider tube 34 from a sealing alloy.
  • Said soft magnetic tube having an eccentric thickness distribution serves to concentrate the electron beam in the center 36 of the tungsten anode 35 by means of a magnetic system (not shown).
  • the radiation can emanate through a thin beryllium window 37.
  • the screening beaker 32 and the anode tube 33 are coated on the closely adjacent parts with a layer 38 of titanium of 50 AU thickness denoted by broken lines on a heavier layer of copper.
  • the voltage of the tube is 150 kV with a distance between 32 and 33 of 7 mm.
  • the electron gun of a cathode-ray tube for picture display is constituted by a cathode having a surface 40, a first grid 41, a second grid 42, an anode 44 comprising a spout 43, and lens electrodes 45 and 46.
  • the distance between the first and the second grid is 0.25 mm.
  • the first grid is at -l75 volt relative to the cathode, the second grid is at +3,000 volt.
  • the anode 44 is +25 kV relative to the cathode, the electrode 45 +7,200 volt and the electrode 46 again at +25 k.volt.
  • the distance between the spout 43 and the grid 42 is smaller than 1 mm, the mutual distances between the electrodes 44, 45 and 46 are 1 mm.
  • the titanium layer 47 shown in broken lines is provided in a thickness of 20 AU.
  • the narrowing of the gaps between the electrodes 44 to 46 has the advantage that insulating components, for example, supporting rods and the wall of the tube near said gaps which are charged in an uncontrollable manner have less influence on the beam.
  • the vacuum switch consists of a two-part ceramic housing 50 with terminating plates 51 and 52 of copper. Electrodes 53 and 54 are secured to the plates by means of a bellows 55 and a rod,respectively. Three screening electrodes 56, 57 and 58 screen the wall 50 from sputtering material. Coming from the electrodes. The closely adjacent edges of the screening electrodes are coated with the titanium layer 59 of 50 AU denoted by broken lines. The distances are 5 mm and the voltage of the opened switch kV eff 50 Hz.
  • An electrode system comprising a plurality of nonemitting members, and means for producing high intensity electrical fields between said members, said members essentially consisting of copper having a metal coating selected from the group consisting of titanium and zirconium, said coating having a thickness of 10 to 50 angstrom units.
  • An electron discharge tube comprising an evacuated envelope, a plurality of non-emitting electrodes closely spaced from each other, and means for applying potentials to said electrodes thereby producing high intensity electric fields between said electrodes, said electrodes essentially consisting of copper having a coating, varying in thickness between 10 and 50 angstron units selected from the group consisting of titanium and zirconium.

Landscapes

  • X-Ray Techniques (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Particle Accelerators (AREA)
US00154348A 1970-06-30 1971-06-18 Device comprising an electric high vacuum discharge tube provided with at least two electrodes not destined for emission, and discharge tube for such a device Expired - Lifetime US3761761A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7009601A NL7009601A (enrdf_load_html_response) 1970-06-30 1970-06-30

Publications (1)

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US3761761A true US3761761A (en) 1973-09-25

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US00154348A Expired - Lifetime US3761761A (en) 1970-06-30 1971-06-18 Device comprising an electric high vacuum discharge tube provided with at least two electrodes not destined for emission, and discharge tube for such a device

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Country Link
US (1) US3761761A (enrdf_load_html_response)
JP (1) JPS471817A (enrdf_load_html_response)
CA (1) CA934430A (enrdf_load_html_response)
DE (1) DE2128921C3 (enrdf_load_html_response)
FR (1) FR2100082A5 (enrdf_load_html_response)
GB (1) GB1309379A (enrdf_load_html_response)
NL (1) NL7009601A (enrdf_load_html_response)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3956657A (en) * 1972-07-18 1976-05-11 Robert Bosch G.M.B.H. Pre-ignition gap
US3993923A (en) * 1973-09-20 1976-11-23 U.S. Philips Corporation Coating for X-ray tube rotary anode surface remote from the electron target area
US4050914A (en) * 1976-07-26 1977-09-27 S.A.E.S. Getters S.P.A. Accelerator for charged particles
US4196938A (en) * 1978-06-07 1980-04-08 Blokin Vladimir I Gas-discharge chamber electrode and electrode system using same
US4757166A (en) * 1987-06-15 1988-07-12 Westinghouse Electric Corp. Vacuum interrupter with ceramic enclosure
US20050130550A1 (en) * 2001-12-20 2005-06-16 Pascal Ponard Method for making electrodes and vacuum tube using same
CN101894722A (zh) * 2010-08-06 2010-11-24 蒋贤华 一种真空放电管
CN108257835A (zh) * 2018-02-07 2018-07-06 东莞市阿甘半导体有限公司 一种气体放电管及过压保护装置

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2639033C3 (de) * 1976-08-30 1981-07-23 Gkss - Forschungszentrum Geesthacht Gmbh, 2000 Hamburg Bauteil in mit Ladungsträgerstrahlen arbeitenden elektrischen Vakuumgeräten und Verfahren zu dessen Herstellung
NL7905720A (nl) * 1979-07-24 1981-01-27 Hazemeijer Bv Werkwijze voor het verbeteren van schakelkontakten, in het bijzonder voor vakuumschakelaars.
JPS6264032A (ja) * 1985-09-13 1987-03-20 Shimadzu Corp 電子管
DE4329518A1 (de) * 1993-08-28 1994-01-05 Slamecka Ernst Vakuumschalter-Kontaktanordnung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2734003A (en) * 1956-02-07 Method for treating metals
US2846609A (en) * 1954-02-08 1958-08-05 Philips Corp Non-emissive electrode for electron discharge device
NL6401843A (enrdf_load_html_response) * 1964-02-13 1965-08-27

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2734003A (en) * 1956-02-07 Method for treating metals
US2846609A (en) * 1954-02-08 1958-08-05 Philips Corp Non-emissive electrode for electron discharge device
NL6401843A (enrdf_load_html_response) * 1964-02-13 1965-08-27

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3956657A (en) * 1972-07-18 1976-05-11 Robert Bosch G.M.B.H. Pre-ignition gap
US3993923A (en) * 1973-09-20 1976-11-23 U.S. Philips Corporation Coating for X-ray tube rotary anode surface remote from the electron target area
US4050914A (en) * 1976-07-26 1977-09-27 S.A.E.S. Getters S.P.A. Accelerator for charged particles
US4196938A (en) * 1978-06-07 1980-04-08 Blokin Vladimir I Gas-discharge chamber electrode and electrode system using same
US4757166A (en) * 1987-06-15 1988-07-12 Westinghouse Electric Corp. Vacuum interrupter with ceramic enclosure
US20050130550A1 (en) * 2001-12-20 2005-06-16 Pascal Ponard Method for making electrodes and vacuum tube using same
US7812540B2 (en) * 2001-12-20 2010-10-12 Thales Method for making electrodes and vacuum tube using same
CN101894722A (zh) * 2010-08-06 2010-11-24 蒋贤华 一种真空放电管
CN101894722B (zh) * 2010-08-06 2014-04-16 蒋贤华 一种真空放电管
CN108257835A (zh) * 2018-02-07 2018-07-06 东莞市阿甘半导体有限公司 一种气体放电管及过压保护装置

Also Published As

Publication number Publication date
DE2128921C3 (de) 1978-05-24
DE2128921A1 (de) 1972-01-05
FR2100082A5 (enrdf_load_html_response) 1972-03-17
CA934430A (en) 1973-09-25
JPS471817A (enrdf_load_html_response) 1972-01-29
DE2128921B2 (de) 1977-09-15
GB1309379A (en) 1973-03-07
NL7009601A (enrdf_load_html_response) 1972-01-03

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