EP0456550B1 - Elektronenröhre mit zylinderförmigem Gitter - Google Patents

Elektronenröhre mit zylinderförmigem Gitter Download PDF

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Publication number
EP0456550B1
EP0456550B1 EP91401116A EP91401116A EP0456550B1 EP 0456550 B1 EP0456550 B1 EP 0456550B1 EP 91401116 A EP91401116 A EP 91401116A EP 91401116 A EP91401116 A EP 91401116A EP 0456550 B1 EP0456550 B1 EP 0456550B1
Authority
EP
European Patent Office
Prior art keywords
grid
cathode
mesh
meshes
valve according
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
EP91401116A
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English (en)
French (fr)
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EP0456550A1 (de
Inventor
Michel-Pierre Tardy
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 Electron Devices SA
Original Assignee
Thomson Tubes Electroniques
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Publication date
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Publication of EP0456550A1 publication Critical patent/EP0456550A1/de
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    • 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
    • H01J19/28—Non-electron-emitting electrodes; Screens
    • H01J19/38—Control electrodes, e.g. grid
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J21/00—Vacuum tubes
    • H01J21/02—Tubes with a single discharge path
    • H01J21/06—Tubes with a single discharge path having electrostatic control means only
    • H01J21/10—Tubes with a single discharge path having electrostatic control means only with one or more immovable internal control electrodes, e.g. triode, pentode, octode

Definitions

  • the present invention relates to cylindrical concentric power electrode tubes. These tubes are, for example, triodes or tetrodes.
  • a triode tube mainly comprises a central cylindrical cathode emitting electrons when it has reached a sufficient temperature, a control grid around the cathode, an anode surrounding the control grid.
  • the electrons emitted by the cathode pass through the grid and reach the anode, if the potential of the grid and the anode have appropriate values.
  • the tetrodes have an additional grid, called a screen grid inserted between the control grid and the anode.
  • the cathode is often made from two layers of emissive metallic wires which are crossed in order to obtain a mesh.
  • the assembly thus produced has a cylindrical structure. Each end of the cylinder is fixed on a support. These cathodes are called cages.
  • the grids are also meshed. They can be made from sheets of son of a refractory material which is crossed in order to obtain a mesh. The wires are welded together at each intersection. The assembly thus formed has a cylindrical structure and its ends are connected to supports.
  • a second way of making a grid is to take a sheet of refractory material, in the shape of a cylinder, and to pierce it with regularly spaced openings in order to obtain the mesh.
  • pyrolitic graphite or molybdenum is commonly used as refractory material.
  • Each mesh is defined by a succession of bars connected by their ends and the intersection between two bars is a knot.
  • the cathode and the grids due to this very cut structure, are subject to vibrations affecting their mechanical stability.
  • the distance between the cathode and the control grid is small, generally less than 1000 micrometers, and the vibrations which may occur cause appreciable variations in this distance. These vibrations are detrimental to the proper functioning of the tube.
  • the same remarks apply to intergrid distances in the case of tetrodes or other multigrid tubes.
  • the importance of mechanical stability will be measured, adding that the cathode can operate at a high operating temperature (of the order of 1700 ° C.) and that it must also have good resistance to deformation.
  • the grids will reach a lower temperature (around 1200 ° C) but must also have good resistance to deformation
  • An ideal grid in terms of potential and transparency would have an infinity of vertical and very fine wires.
  • the gate current would be very low and the gate potential distributed very regularly around the cathode.
  • this grid would have extremely poor mechanical strength, especially if it had large dimensions.
  • the grids used frequently have meshes in the form of quadrilaterals: square, rectangle, rhombus or parallelogram. From a knot of mesh leave four bars.
  • patent DE-C-868 320 the grid is produced by stretching a strip provided with slots arranged in staggered rows. The finished grid has parallelogram type meshes.
  • Hexagonal mesh grids are known in linear beam tubes.
  • the grid is flat or in a cap.
  • it is a grid for camera tube.
  • US Patent 4,767,964 it is a grid for cathode ray tube.
  • the present invention aims to remedy these drawbacks and proposes a grid tube operating with a reduced grid current. For this, we sought to minimize the interception surface of the electrons, without harming either the mechanical stability or the distribution of the gate potential around the cathode.
  • the present invention relates to an electronic tube with concentric cylindrical electrodes including a central cathode and at least one grid of the mesh type, a mesh being defined by several bars in contact at their ends.
  • the cathode has two groups of substantially parallel wires, the two groups being crossed.
  • the grid meshes are hexagonal and the intersection between two cathode wire is aligned with the central part of a grid mesh.
  • the meshes are substantially identical.
  • the hexagons are substantially regular.
  • the rod and the wire are perpendicular to minimize the overlap area.
  • the meshes are produced from a sheet of refractory material in the form of a cylinder pierced with hexagonal orifices.
  • the material can be pyrolitic graphite or molybdenum.
  • FIG. 1a represents a mesh in parallelogram of an electron tube grid, of the triode type for example.
  • Figure 1b shows it, a diamond mesh.
  • Each of these meshes can be produced from two substantially parallel layers of wires 1,2, which are superimposed by crossing them.
  • the wires 1 of a ply are then welded to the wires 2 of the other ply, at all the crossing points.
  • Each crossing forms a knot 3. From each node 3 leave four bars 5.
  • a mesh 4 consists of four bars 5.
  • a mesh 4 has the shape of a parallelogram, it consists of four equal bars, two by two.
  • a mesh 4 has the shape of a rhombus, it consists of four equal bars 5.
  • the wires 1,2 used to make these grids are made of refractory metal, for example molybdenum.
  • a grid of this type can also be made from a sheet of refractory material of graphite or molybdenum for example.
  • the sheet is pierced with openings by any known means, machining, sandblasting or EDM, for example.
  • the openings are preferably regularly spaced and have an appropriate shape to obtain the mesh.
  • An electron tube grid for example a triode grid, is cylindrical and it is mounted around a cathode emitting electrons. The electrons pass through the grid when the latter is brought to a negative potential compared to that of the cathode.
  • the bars 5 and the nodes 3 form an electron screen.
  • Certain electrons are intercepted by the structure of the grid when it is brought to a positive potential compared to that of the cathode. The intercepted electrons cause the appearance of a gate current.
  • a high grid current causes an excessive increase in the temperature of the grid and requires the use of a powerful grid supply.
  • FIG. 3 represents a regular hexagonal mesh of an electron tube grid according to the prior art. This mesh has nodes 36. From each node 36, only three bars 35 leave.
  • each mesh 34 is hexagonal it is defined by six bars 35 connected by their ends.
  • the surface of the nodes 36 has been reduced compared to the meshes conventionally used.
  • the electrons intercepted by a grid of this type will be less numerous and an electronic power tube having a grid of this type will have a reduced grid current compared to the grid current of a conventional power tube.
  • each mesh 34 is made up of equal bars 35 and two successive bars 35 make an angle of 120 °. All the meshes are substantially identical.
  • the meshes are not all identical and that the hexagons are irregular.
  • Such a mesh is shown in FIG. 4.
  • Large meshes 41 have been shown in line and smaller meshes 42 also aligned.
  • Each mesh 41 or 42 is an irregular hexagon.
  • the angles between two successive bars can be larger or smaller than 120 °.
  • Figure 5 is a view of a mesh grid of electron tube according to the prior art.
  • the grid has 50 regular hexagonal meshes. It has a honeycomb structure. It comprises a meshed part 51 of cylindrical shape. The two ends 52 of the cylinder are each held on a support 53.
  • the grid will be produced from a sheet of refractory material, for example pyrolitic graphite, molybdenum, in the form of a cylinder.
  • a sheet of refractory material for example pyrolitic graphite, molybdenum
  • We cut holes. in this sheet by any known means, machining, sandblasting, EDM, for example.
  • the orifices are distributed regularly over the entire sheet. They are given the shape of hexagons. We obtain a hexagonal mesh. Each end of the cylinder is fixed on a support.
  • the interception surface has been reduced, at the level of the nodes, if we compare it to that of the grids with triangular meshes and meshes in the form of a quadrilateral.
  • the regularity of the hexagons and their orientation are chosen according to the mechanical and electrical parameters that the grid must have.
  • the geometry of the bars that is to say their length and their cross section, as well as the angle of intersection between two bars are chosen so as to ensure transparency to the electrons and a control of the potential around the cathode, corresponding to the characteristics that the tube must have.
  • a regular hexagonal mesh allows smaller meshes than those usually used. This results in better control of the potentials between the bars and near the cathode (if the grid is a control grid), an improvement in the tube blocking voltage or "cutt off" as well as a better distribution of the electron trajectories.
  • a regular hexagonal mesh allows larger meshes than those usually used. This results in greater transparency of the grid and a reduction in the grid current, in particular in high power operation.
  • FIG. 6 represents a mesh 60 of a cage cathode covered with a mesh 70 of the control grid of an electronic tube according to the invention.
  • the cathode mesh 60 consists of two groups of wires 61, 62 which are substantially parallel, the two groups being crossed. We made 63 diamond shaped meshes.
  • the wires 61,62 of the cathode emit electrons when they are heated.
  • An intersection 64 between two wires 61, 62 has a large surface which emits a high density of electrons.
  • the grid mesh 70 comprises hexagonal and regular meshes 65 made up of bars 66.
  • all the grids will be aligned with one another and will be identical, so that the intersection 64 between two cathode wires 61, 62 is placed in the central part of all the grid meshes.
  • the invention applies both to control grids and to other grids (screen grid, stop grid %)
  • This type of hexagonal mesh is particularly suitable for tubes in which the interelectrode distance is small because the mesh offers very good mechanical stability and very good resistance to deformation.
  • the hexagonal mesh makes it possible to minimize the grid current and to properly control the potential between the bars.
  • a grid with hexagonal meshes can advantageously be integrated into a tube of high gain and low attack power.

Landscapes

  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)

Claims (8)

  1. Elektronenröhre mit konzentrischen zylindrischen Elektroden, wozu eine zentrale Kathode und wenigstens ein Gitter mit Maschen gehören, wobei eine Masche (34) durch mehrere Stege (35) gebildet ist, die einander an ihren Enden berühren, dadurch gekennzeichnet, daß die Kathode zwei Gruppen von Drähten (61, 62) enthält, die zueinander im wesentlichen parallel sind, wobei die beiden Gruppen einander kreuzen, und daß die Gittermaschen (65) hexagonal sind, wobei die Kreuzungsstelle zwischen zwei Kathodendrähten (61, 62) auf den zentralen Teil einer Gittermasche (65) ausgerichtet ist.
  2. Elektronenröhre nach Anspruch 1, dadurch gekennzeichnet, daß die Maschen (34) im wesentlichen identisch sind.
  3. Elektronenröhre nach einem der Ansprüche 1 und 2, dadurch gekennzeichnet, daß die Hexagone im wesentlichen regelmäßig sind.
  4. Elektronenröhre nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die Kathodendrähte (61, 62) Rauten bilden.
  5. Elektronenröhre nach Anspruch 4, dadurch gekennzeichnet, daß dann, wenn ein Gittersteg (66) einen Kathodendraht (61, 62) abdeckt, der Gittersteg (66) und der Kathodendraht (61, 62) zueinander senkrecht sind, um die Überdeckungsfläche zu minimieren.
  6. Elektronenröhre nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die Maschen (34) durch Öffnungen gebildet sind, die in einem zylindrischen Blatt aus hitzebeständigem Material gebildet sind.
  7. Elektronenröhre nach Anspruch 6, dadurch gekennzeichnet, daß das Material Pyrographit ist.
  8. Elektronenröhre nach Anspruch 6, dadurch gekennzeichnet, daß das Material Molybdän ist.
EP91401116A 1990-05-11 1991-04-26 Elektronenröhre mit zylinderförmigem Gitter Expired - Lifetime EP0456550B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9005903 1990-05-11
FR9005903A FR2662020B1 (fr) 1990-05-11 1990-05-11 Tube electronique a grille cylindrique.

Publications (2)

Publication Number Publication Date
EP0456550A1 EP0456550A1 (de) 1991-11-13
EP0456550B1 true EP0456550B1 (de) 1996-05-22

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EP91401116A Expired - Lifetime EP0456550B1 (de) 1990-05-11 1991-04-26 Elektronenröhre mit zylinderförmigem Gitter

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US (1) US5225735A (de)
EP (1) EP0456550B1 (de)
DE (1) DE69119645D1 (de)
FR (1) FR2662020B1 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7049614B2 (en) * 2003-03-10 2006-05-23 Intel Corporation Electrode in a discharge produced plasma extreme ultraviolet source
KR20080072644A (ko) * 2005-11-03 2008-08-06 레드포인트 바이오 코포레이션 Ｔｒｐｍ5 이온 채널용 고속 처리 스크리닝 검정
WO2007134432A1 (en) 2006-05-18 2007-11-29 Valerian Pershin Highly ordered structure pyrolitic graphite or carbon-carbon composite cathodes for plasma generation in carbon containing gases
US20170284567A1 (en) * 2016-03-30 2017-10-05 The Boeing Company Grommet, conduit support assembly, and method of supporting a conduit

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2358011A1 (fr) * 1976-07-07 1978-02-03 Thomson Csf Procede de fabrication de grille hexagonale pour tube electronique, grille obtenue par ce procede et tube electronique comportant une telle grille
US4684994A (en) * 1985-02-07 1987-08-04 U.S. Philips Corporation Television camera tube with honeycomb grid electrode
US4767964A (en) * 1987-02-04 1988-08-30 Tektronix, Inc. Improved mesh for CRT scan expansion lens and lens fabricated therefrom

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE868320C (de) * 1950-03-21 1953-02-23 Siemens Ag Elektronenroehre
DE1134167B (de) * 1960-12-14 1962-08-02 Standard Elektrik Lorenz Ag Gitter fuer die gebuendelte Elektronenstroemung von Kathodenstrahl- oder Laufzeitroehren und Verfahren zu seiner Herstellung
US3573535A (en) * 1968-11-12 1971-04-06 Gen Electric High-frequency electronic tube having novel grid mounting
US3798539A (en) * 1973-02-15 1974-03-19 Magnetic Analysis Corp Pulse eddy current testing apparatus using pulses having a 25% duty cycle with gating at pulse edges
FR2276681A1 (fr) * 1974-06-28 1976-01-23 Thomson Csf Grille pour tube electronique et tube comportant une telle grille
US4230968A (en) * 1976-05-26 1980-10-28 Hitachi, Ltd. Cathode structure for magnetrons
US4254357A (en) * 1979-09-14 1981-03-03 The United States Of America As Represented By The Secretary Of The Navy Multi-arrayed micro-patch emitter with integral control grid
US4695760A (en) * 1982-01-18 1987-09-22 General Electric Company Self-aligned double grids for vacuum tubes
DE3369423D1 (en) * 1982-07-27 1987-02-26 Bbc Brown Boveri & Cie Electronic tube, particularly an emitter tube
FR2566959B1 (fr) * 1984-06-29 1987-02-20 Thomson Csf Dispositif de fixation d'une grille en graphite pyrolytique sur l'embase d'un tube electronique
NL8500220A (nl) * 1985-01-28 1986-08-18 Philips Nv Elektronenbuis.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2358011A1 (fr) * 1976-07-07 1978-02-03 Thomson Csf Procede de fabrication de grille hexagonale pour tube electronique, grille obtenue par ce procede et tube electronique comportant une telle grille
US4684994A (en) * 1985-02-07 1987-08-04 U.S. Philips Corporation Television camera tube with honeycomb grid electrode
US4767964A (en) * 1987-02-04 1988-08-30 Tektronix, Inc. Improved mesh for CRT scan expansion lens and lens fabricated therefrom

Also Published As

Publication number Publication date
FR2662020A1 (fr) 1991-11-15
US5225735A (en) 1993-07-06
EP0456550A1 (de) 1991-11-13
FR2662020B1 (fr) 1996-04-19
DE69119645D1 (de) 1996-06-27

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