EP0350359A1 - Verfahren zur Herstellung einer Röntgenbildverstärkerröhre und nach diesem Verfahren hergestellte Bildverstärkerröhre - Google Patents

Verfahren zur Herstellung einer Röntgenbildverstärkerröhre und nach diesem Verfahren hergestellte Bildverstärkerröhre Download PDF

Info

Publication number
EP0350359A1
EP0350359A1 EP89401743A EP89401743A EP0350359A1 EP 0350359 A1 EP0350359 A1 EP 0350359A1 EP 89401743 A EP89401743 A EP 89401743A EP 89401743 A EP89401743 A EP 89401743A EP 0350359 A1 EP0350359 A1 EP 0350359A1
Authority
EP
European Patent Office
Prior art keywords
electrode
anode
photocathode
tube
alkali metals
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.)
Granted
Application number
EP89401743A
Other languages
English (en)
French (fr)
Other versions
EP0350359B1 (de
Inventor
Gérard Vieux
Francis Diaz
Paul De Groot
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.)
Thales SA
Original Assignee
Thomson CSF SA
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 Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0350359A1 publication Critical patent/EP0350359A1/de
Application granted granted Critical
Publication of EP0350359B1 publication Critical patent/EP0350359B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/50—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output
    • H01J31/501—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output with an electrostatic electron optic system
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/12—Manufacture of electrodes or electrode systems of photo-emissive cathodes; of secondary-emission electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/14—Manufacture of electrodes or electrode systems of non-emitting electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/32—Secondary emission electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/34—Photoemissive electrodes
    • H01J2201/342—Cathodes
    • H01J2201/3421—Composition of the emitting surface
    • H01J2201/3426—Alkaline metal compounds, e.g. Na-K-Sb

Definitions

  • the present invention relates to a method for manufacturing an improved radiological image intensifier tube (I.I.R.). It also relates to the high vacuum tubes intensifiers of radiological images thus obtained.
  • I.I.R. improved radiological image intensifier tube
  • Radiological image intensifier tubes or I.I.R. are well known in the prior art. They transform a radiological image into a visible image, for example to ensure medical observation.
  • the problem which arises and which the present invention seeks to solve is that one observes in the I.I.R. even in the absence of X-rays, annoying parasitic lighting of the observation screen.
  • This stray light is due to the alkali metals involuntarily deposited on the electrodes of the I.I.R. during the development of the photocathode.
  • the intense electric field which reigns in the tube manages to tear electrons from these alkali metals which are very electro-positive, and therefore very easily ionizable. These electrons go up the electric field, strike the observation screen and create parasitic lighting.
  • photocathodes of the alkaline antimonide type are done in the vacuum enclosure of the I.I.R. because alkali metals are very reactive and must be created under vacuum to be stable.
  • These photocathodes can be produced by successive evaporations of their constituent elements, in the tube, using a conventional crucible containing antimony, which is caused to evaporate by heating the crucible, by Joule effect for example.
  • the alkali metals are evaporated from generators usually located on the electrode closest to the anode.
  • the evaporation of alkali metals is the result of a silicothermia or an aluminothermy of the chromates of the metals that one seeks to evaporate.
  • Silicothermia or aluminothermia are triggered by heating by Joule effect of alkaline generators.
  • Alkaline generators are much less directive than antimony generators. This is due to the fact that it is necessary for silicothermia or aluminothermia to occur under good conditions to use special crucibles in which the chromates are confined. This type of crucible has poor directivity which has the advantage of ensuring a very uniform deposition of alkali metals over the entire surface of the photocathode which is distant from these crucibles. On the other hand, it has the drawback of causing the deposition of alkali metals on all the parts of the I.I.R.tube, and in particular on the electrodes, which causes the problem of stray lighting of the observation screen.
  • a solution used by the Applicant is to cover with a layer of aluminum oxide Al2O3, the electrode closest to the anode, generally made of aluminum itself.
  • This solution eliminates stray lighting from the observation screen, but introduces electrical discharges through this oxide layer, which is an electrical insulator.
  • Another known solution to the problem mentioned which does not have the drawbacks of the known solution, consists in that, before introducing it into the intensifier, a layer is deposited, at least on part of one or more electrodes. of an electrically conductive material and having the property of oxidizing the alkali metals which are used in the composition of the photocathode.
  • This material can be chosen from the following bodies: Te, Se, S, P.
  • the present invention intends to propose a variant of this second solution which preserves the advantages of a conductive layer of electrons from the alkali metals while making its application and its implementation simpler.
  • the first object of the invention is a method of manufacturing an improved tube for intensifying radiological images, with in particular a photocathode comprising an alkaline antimonire, several electrodes and an anode, according to which, prior to the manufacture of the cathode by means of a vaporization of antimony and alkali metals, a layer of conductive material is deposited, before introducing it into the tube, on at least part of the electrode closest to the anode having the property of reacting with the above-mentioned alkali metals.
  • the conductive material is chosen from organic polymers that conduct electricity electronically.
  • a second object of the invention is an improved radiological image intensifier tube, in particular with a photocathode comprising an alkaline antimonire, several electrodes and an anode in which at least a part of at least one electrode and parts electrically connected to a electrode or at the anode of the intensifier carries a layer of organic polymer electronically conductive of electricity having the property of reacting chemically with the alkali metals which enter into the composition of the photocathode.
  • An intensifier of radiological images represented diagrammatically, seen in longitudinal section in FIG. 1, is constituted by an input screen, an electronic optical system and an observation screen contained in a vacuum enclosure 1.
  • the input screen includes a scintillator 2 which converts the incident X photons into visible photons, a photocathode 3 which converts the visible photons into electrons. Between the scintillator and the photocathode, an electrically conductive sublayer is generally inserted, the role of which is to re-supply the photocathode with electrical charges while it emits its electrons. This sublayer is not shown in FIG. 1.
  • the scintillator may consist, for example, of cesium iodide doped with sodium or with thallium.
  • the photocathode can consist of an alkaline antimonide.
  • the conductive sublayer may consist, for example, of indium oxide of formula In2O3.
  • the electronic optical system generally consists of three electrodes G1, G2, G3 and an anode A which carries the observation screen 4.
  • Photocathode 3 is generally connected to the ground of the tube.
  • the electrodes G1, G2, G3 and the anode A are brought to electric potentials increasing up to 30 KV for example;
  • An electric field E is therefore created in the tube, directed along the longitudinal axis of the tube, towards the photocathode. Electrons from the remon photocathode try this field and strike the observation screen 4, made of a cathodoluminescent material such as zinc sulphide, for example, which makes it possible to obtain a visible image.
  • the reference 7 denotes the layer of alkali metals deposited on the grid G3 during the manufacture of the cathode and which, under the action of the electric field E, prevailing between the grid G3 and the anode A and directed towards the grid G3, releases electrons which go up the electric field and come to strike the observation screen 4.
  • FIG. 3 represents a view in partial section of the electrode G3 and of the anode A of the I.I.R. of Figure 1, illustrating the solution provided by the invention to the problem of stray lighting previously mentioned.
  • the problem of stray lighting is due to the metallic nature of the parasitic alkalies.
  • the solution proposed by the invention is to chemically react these alkali metals with a material capable of transforming them into ionic or covalent compounds.
  • the alkali metals are fixed and no longer release electrons creating the stray light that we are trying to remove.
  • the deposit used must also conduct electricity so as to avoid the discharge phenomena encountered in the prior art when an oxide layer covers the G3 electrode.
  • the present invention it is proposed to cover one or all of the electrodes G1, G2, and G3 as well as any internal part of the tube capable of receiving alkali metals with an organic polymer that conducts electricity.
  • This conductive organic polymer may cover all or only part of the electrode or part concerned.
  • the conductive organic polymer may - by way of non-exhaustive examples - be polypyrrole, polythiophene, polyaniline, polyvinylferrocene (PVF), polythiazil, polyacethylene, polyparaphenylene, or any other electronic conductive polymer.
  • FIG. 3 it is shown that the electrode G rec is covered with a layer 8 of polymer before being introduced into the I.I.R. It is possible to cover the entire electrode G3 with polymer as is the case in FIG. 3, or only the areas of the electrode G3 which are most likely to cause the phenomenon of stray lighting. These areas can be determined experimentally. They can also be determined by calculation using computer programs. The zones which are most likely to cause the parasitic lighting phenomenon are generally very curved zones whose radius of curvature is small and whose electric field is strong. These areas are located near the alkaline generators and the observation screen. In FIG. 3, it can be seen that the periphery of the orifice of the electrode G3 has been covered with layer 8 which allows the passage of electrons.
  • oxidized form is conductive
  • reduced form is insulating
  • the ferric ion is the oxidizing ion
  • the ClO4 ion is used to respect the electroneutrality of the polymer: nFe3+ + ne ⁇ nFe2+ nPY ⁇ nPY ⁇ + ne ⁇ nPY ⁇ + n ClO4 ⁇ ⁇ [PY, ClO4] n
  • Polypyrrole is thus formed on the electrode G3 for example, present in the reaction bath.
  • the second method of obtaining is electrochemical oxidation in which oxidation and polymerization are carried out on the electrode connected to the positive terminal of the electric generator, the bath being composed of the basic monomer - for example pyrrole - diluted in an organic or aqueous solvent

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Electroluminescent Light Sources (AREA)
EP89401743A 1988-07-08 1989-06-20 Verfahren zur Herstellung einer Röntgenbildverstärkerröhre und nach diesem Verfahren hergestellte Bildverstärkerröhre Expired - Lifetime EP0350359B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8809310A FR2634057B1 (fr) 1988-07-08 1988-07-08 Procede de fabrication d'un tube perfectionne intensificateur d'images radiologiques, tube intensificateur ainsi obtenu
FR8809310 1988-07-08

Publications (2)

Publication Number Publication Date
EP0350359A1 true EP0350359A1 (de) 1990-01-10
EP0350359B1 EP0350359B1 (de) 1993-08-25

Family

ID=9368261

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89401743A Expired - Lifetime EP0350359B1 (de) 1988-07-08 1989-06-20 Verfahren zur Herstellung einer Röntgenbildverstärkerröhre und nach diesem Verfahren hergestellte Bildverstärkerröhre

Country Status (5)

Country Link
US (1) US4943254A (de)
EP (1) EP0350359B1 (de)
JP (1) JPH0268832A (de)
DE (1) DE68908637T2 (de)
FR (1) FR2634057B1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0608168A1 (de) * 1993-01-22 1994-07-27 Thomson Tubes Electroniques Bildumwandlungsröhre und Verfahren zur Unterdrucken von Störungen in der Röhre
EP0790640A3 (de) * 1996-02-15 1997-11-19 General Electric Company Elektrodenlose Entladungslampe

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02152143A (ja) * 1988-12-02 1990-06-12 Toshiba Corp Ｘ線イメージ管及びその製造方法
FR2688343A1 (fr) * 1992-03-06 1993-09-10 Thomson Tubes Electroniques Tube intensificateur d'image notamment radiologique, du type a galette de microcanaux.
FR2698482B1 (fr) * 1992-11-20 1994-12-23 Thomson Tubes Electroniques Dispositif générateur d'images par effet de luminescence.
FR2777112B1 (fr) 1998-04-07 2000-06-16 Thomson Tubes Electroniques Dispositif de conversion d'une image
FR2782388B1 (fr) 1998-08-11 2000-11-03 Trixell Sas Detecteur de rayonnement a l'etat solide a duree de vie accrue

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0249547A2 (de) * 1986-06-13 1987-12-16 Thomson-Csf Verfahren zur Herstellung eines Röntgenbildverstärkers und nach diesem Verfahren hergestellter Bildverstärker

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2212579A1 (de) * 1972-03-15 1973-09-27 Siemens Ag Vakuum-bildwandler
JPS5736758A (en) * 1980-08-14 1982-02-27 Nec Corp Image tube

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0249547A2 (de) * 1986-06-13 1987-12-16 Thomson-Csf Verfahren zur Herstellung eines Röntgenbildverstärkers und nach diesem Verfahren hergestellter Bildverstärker

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0608168A1 (de) * 1993-01-22 1994-07-27 Thomson Tubes Electroniques Bildumwandlungsröhre und Verfahren zur Unterdrucken von Störungen in der Röhre
FR2700889A1 (fr) * 1993-01-22 1994-07-29 Thomson Tubes Electroniques Tube convertisseur d'images, et procédé de suppression des lueurs parasites dans ce tube.
EP0790640A3 (de) * 1996-02-15 1997-11-19 General Electric Company Elektrodenlose Entladungslampe
US6097137A (en) * 1996-02-15 2000-08-01 General Electric Company Electrodeless discharge lamp

Also Published As

Publication number Publication date
FR2634057A1 (fr) 1990-01-12
JPH0268832A (ja) 1990-03-08
DE68908637T2 (de) 1993-12-23
FR2634057B1 (fr) 1991-04-19
DE68908637D1 (de) 1993-09-30
US4943254A (en) 1990-07-24
EP0350359B1 (de) 1993-08-25

Similar Documents

Publication Publication Date Title
US6045677A (en) Microporous microchannel plates and method of manufacturing same
EP0350359B1 (de) Verfahren zur Herstellung einer Röntgenbildverstärkerröhre und nach diesem Verfahren hergestellte Bildverstärkerröhre
JP3084713B2 (ja) シンチレータの作成方法及びその方法で得られるシンチレータ
US2586304A (en) Protection of phosphors from attack by alkali vapors
WO2007102471A1 (ja) 光電面、それを備える電子管及び光電面の製造方法
US3525679A (en) Method of electrodepositing luminescent material on insulating substrate
EP0093282A1 (de) Lithiumzelle mit festem Elektrolyten aus einer glasartigen leitenden Zusammensetzung
JP2918524B2 (ja) プラズマディスプレイパネル保護層およびその形成方法
JPH01209637A (ja) Ｘ線イメージ増倍管用の入力スクリーンシンチレータの製造方法
EP0249547B1 (de) Verfahren zur Herstellung eines Röntgenbildverstärkers und nach diesem Verfahren hergestellter Bildverstärker
US6049168A (en) Method and system for manufacturing microchannel plates
EP0044239B1 (de) Bildverstärkerröhre mit Mikrokanälen und solch eine Röhre enthaltende Bildaufnahmeeinheit
US5367155A (en) X-ray image intensifier tube with improved entrance section
JPH023262B2 (de)
JP3529152B2 (ja) 画像変換管及び該管の製造方法
DE2202217B2 (de) Verfahren zum Herstellen einer eine Elektronenquelle enthaltenden Einrichtung
JP3054032B2 (ja) 電子管
FR2650438A1 (fr) Procede de fabrication de tube perfectionne intensificateur d'image, tube intensificateur ainsi obtenu
JPH0125181B2 (de)
US3232781A (en) Electron image intensifying devices
US3666547A (en) Photo-cathodes for electronic discharge tubes
EP0561621A1 (de) Bildröhre
JPS635853B2 (de)
RU1816329C (ru) Способ изготовлени фотокатода
JPS58135548A (ja) 直接変換型ｘ線イメ−ジインテンシフアイア

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB NL

17P Request for examination filed

Effective date: 19900117

17Q First examination report despatched

Effective date: 19920818

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB NL

REF Corresponds to:

Ref document number: 68908637

Country of ref document: DE

Date of ref document: 19930930

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19931101

RAP2 Party data changed (patent owner data changed or rights of a patent transferred)

Owner name: THOMSON-CSF

NLT2 Nl: modifications (of names), taken from the european patent patent bulletin

Owner name: THOMSON-CSF TE PARIJS, FRANKRIJK.

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19960514

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19960516

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19960517

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19960621

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19970620

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19980101

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19970620

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980227

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 19980101

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980303

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST