EP0045932B1 - Méthode pour raccourcir le temps de chauffage d'une cathode à chauffage indirect - Google Patents

Méthode pour raccourcir le temps de chauffage d'une cathode à chauffage indirect Download PDF

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Publication number
EP0045932B1
EP0045932B1 EP81106086A EP81106086A EP0045932B1 EP 0045932 B1 EP0045932 B1 EP 0045932B1 EP 81106086 A EP81106086 A EP 81106086A EP 81106086 A EP81106086 A EP 81106086A EP 0045932 B1 EP0045932 B1 EP 0045932B1
Authority
EP
European Patent Office
Prior art keywords
cathode
control cylinder
bias voltage
heating
base plate
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
Application number
EP81106086A
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German (de)
English (en)
Other versions
EP0045932A2 (fr
EP0045932A3 (en
Inventor
Eberhard Weiss
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.)
International Standard Electric Corp
Original Assignee
International Standard Electric Corp
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 International Standard Electric Corp filed Critical International Standard Electric Corp
Publication of EP0045932A2 publication Critical patent/EP0045932A2/fr
Publication of EP0045932A3 publication Critical patent/EP0045932A3/de
Application granted granted Critical
Publication of EP0045932B1 publication Critical patent/EP0045932B1/fr
Expired legal-status Critical Current

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Classifications

    • 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
    • H01J1/22—Heaters

Definitions

  • the invention relates to a method for shortening the heating time of an indirectly heated cathode for cathode ray tubes such as oscillograph, television and color television picture tubes, in which an electron-emitting layer is located on the outside of a base plate of a cathode tube, which is directly through a arranged inside the cathode tube heated three-pole system is excited to emission, and wherein the inside of the bottom plate of the cathode tube serves as an anode of the three-pole system.
  • an indirectly heated cathode for cathode ray tubes such as oscillograph, television and color television picture tubes
  • the heat source consists of a coiled heating wire which is designed as a double helix or folded in a hairpin shape and covered with an insulating layer consisting essentially of aluminum oxide and is then pushed into the cathode tube.
  • an insulating layer consisting essentially of aluminum oxide and is then pushed into the cathode tube.
  • heavy metal particles are embedded in the insulating aluminum oxide, which give the insulating material the desired radiator properties and a dark color. Examples show DE-AS 23 17 445, 23 17 446 and 23 64 403. With heaters constructed in this way, the heating-up time of the cathode-ray tubes equipped with them could be shortened considerably.
  • DE-OS 29 38 248 proposes to make the distribution of the heating wire windings and / or the insulating material inside the cathode tube so uneven that the center of gravity is very close to the bottom plate of the cathode tube and so the emission layer heats up more quickly.
  • a cathode in which the electron-emitting layer is heated by an electron beam.
  • the cathode is designed as a three-pole system, which consists of a filament, a control cylinder surrounding it and a cover with an attached hollow cone cathode.
  • the cover has a hole in the region of the hollow cone cathode, so that the electron beam of the filament focused by the control cylinder hits the hollow cone cathode on the inside.
  • Very high electron beam densities can be achieved with the known cathode, a heating power of approximately 50 watts and an acceleration voltage of approximately 9000 volts being required, and a positive voltage of 4000 volts being applied to the control cylinder.
  • the operating temperature of the hollow cone cathode is then 2800 Kelvin, which is why water cooling is proposed for the cathode. No information is given on the heating time achieved for this cathode.
  • the present invention has for its object to provide a method for rapid heating of a cathode with a three-pole system, which can be used in cathode ray tubes for television sets.
  • the negative bias of a control cylinder of the three-pole system is reduced from a potential value O or a predetermined negative potential value, based on the potential of a filament of the three-pole system, to a lower negative potential final value and so that the beam current of the three-pole system is reduced so that the emitting layer on the outside of the base plate of the cathode tube receives the desired operating temperature value without overshoot.
  • the increase in the negative bias voltage can be generated in a simple manner in that the voltage source for the negative bias voltage has a high source resistance and when it is switched on a capacitor is connected in parallel, from which the negative bias voltage for the control cylinder is removed.
  • 1 now denotes the Wehnelt cylinder, the position of which is fixed via supporting webs, not shown, which are melted into the glass-ceramic rods carrying the entire system structure.
  • a holder tube 3 In the interior of the Wehnelt cylinder 1, one end of a holder tube 3 is fastened by means of an insulating ring 2 made of glass, glass ceramic or ceramic, with the other, free end of which the cathode tube 4 is connected at points, the end of which facing the Wehnelt cylinder base is closed with a cathode cap 5 made of cathode nickel which then carries the emissive layer 6.
  • control cylinder 7 is now inserted coaxially to the cathode tube 4, in the interior of which a heating filament 8 is arranged at connections (10) located in an insulating disk 9.
  • Filament 8 control cylinder 7 and the inside of the cathode cap 5 now form a directly heated three-pole tube system in which the control cylinder 7 as a control electrode with respect to the filament 8 receives a negative bias and the cathode cap 5 as an anode with respect to the filament 8 receives a positive anode voltage.
  • the electron current emerging from the filament depending on the level of the negative control electrode voltage, is accelerated towards the anode, strikes it and is fully converted into heat as anode power dissipation, since no useful power is drawn from this system.
  • the present three-pole tube structure shows the following special feature compared to a conventional triode system.
  • the control electrode of this three-pole system here does not consist of a wire spiral connected by one or more wire bridges, as in the conventional amplifier tube triode systems, but of a control cylinder 7 coaxial with the cathode tube.
  • the field distribution that forms at the exit of this control cylinder creates an acceleration electron lens that converts the electrons into a narrow beam and directs to the center of the bottom plate of the cathode tube 4 formed by the cathode cap 5, that is to a point which is exactly opposite the bore in the Wehnelt cylinder 1.
  • the area to which heat is emitted can therefore be kept considerably smaller than with the conventional indirectly heated cathodes.
  • cathode tube 4 For the formation of the cathode tube 4, it is irrelevant whether the end facing the Wehnelt cylinder 1 is now closed with a cathode cap 5 made of cathode nickel, as shown in the figure, or whether a base made of cathode nickel, as shown in FIG Figure of DE-AS 28 13 504 shows, or whether according to DE-OS 26 54 554 cathode tubes 4 and cathode cap 5 are made in one piece from an alloy which on the one hand does not adversely affect the emission mass but on the other hand also has the desired poor thermal conductivity, to keep the heat loss low.
  • the heating voltage V H of each system was approximately 2 volts and the heating current averaged 100 mA.
  • the anode voltage V A was approximately 800 volts and the anode current averaged 0.75 mA.
  • the control cylinder preload -V G could be adjusted between 0 and -100V compared to the center of the filament.
  • the previous color picture tubes require a heating current of around 250 mA at 6.3 V heating voltage, i.e.
  • the heating time of a cathode is approximately that Reduce half to a fifth of the usual time with a simultaneous reduction in heating power to about half. Since the thermal load on the system is considerably reduced by the reduced heating power, the convergence problems caused by the influence of heat are considerably reduced.

Landscapes

  • Electrodes For Cathode-Ray Tubes (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Solid Thermionic Cathode (AREA)

Claims (2)

1. Dispositif pour réduire le temps d'échauffement d'une cathode à chauffage indirect d'un tube cathodique pour tube image d'oscillographe, de télévision ou de télévision couleurs, dans lequel une couche émettrice d'électrons (6) se trouve sur la face externe de la plaque de fond (5) d'un tube de cathode (4), qui est excitée en vue de l'émission au moyen d'un système à trois pôles (5, 7, 8) à chauffage direct disposé à l'intérieur du tube de cathode, et dans lequel la face interne de la plaque de fond (5) du tube de cathode fait fonction d'anode du système à trois pôles, caractérisé en ce qu'après la mise en circuit du dispositif, la tension de polarisation négative (-VG) de l'électrode de commande (7) du système à trois pôles est réduite depuis une valeur de potentielle nulle ou depuis une valeur de potentiel négative donnée, spécifique du potentiel du filament de chauffage (8) du système à trois pôles, jusqu'à une valeur de potentiel négative inférieure, pour provoquer une réduction du courant de faisceau du système à trois pôles (5, 7, 8), la couche émettrice (6), située sur la face externe (5) du tube de cathode (4), s'arrêtant à la température souhaitée de fonctionnement sans dépassement.
2. Dispositif selon la revendication 1, caractérisé en ce que la source de tension de polarisation négative (-VG) comporte une résistance de source élevée et en ce qu'elle peut être mise en circuit par commutation d'un condensateur monté en parallèle, aux bornes duquel est prélevée la tension de polarisation de l'électrode de commande (7).
EP81106086A 1980-08-07 1981-08-04 Méthode pour raccourcir le temps de chauffage d'une cathode à chauffage indirect Expired EP0045932B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3029853A DE3029853C2 (de) 1980-08-07 1980-08-07 Indirekt durch Elektronenstoß geheizte Wehneltkathode
DE3029853 1980-08-07

Publications (3)

Publication Number Publication Date
EP0045932A2 EP0045932A2 (fr) 1982-02-17
EP0045932A3 EP0045932A3 (en) 1982-06-09
EP0045932B1 true EP0045932B1 (fr) 1986-05-07

Family

ID=6109051

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81106086A Expired EP0045932B1 (fr) 1980-08-07 1981-08-04 Méthode pour raccourcir le temps de chauffage d'une cathode à chauffage indirect

Country Status (6)

Country Link
US (1) US4401919A (fr)
EP (1) EP0045932B1 (fr)
JP (1) JPS57118333A (fr)
CA (1) CA1182165A (fr)
DE (2) DE3029853C2 (fr)
FI (1) FI71853C (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2644286A1 (fr) * 1989-03-07 1990-09-14 Thomson Tubes Electroniques Generateur de faisceau d'electrons et dispositifs electroniques utilisant un tel generateur
DE19800766C1 (de) * 1998-01-12 1999-07-29 Siemens Ag Elektronenstrahlröhre mit hoher Lebensdauer bei höchsten Strömen
US6091187A (en) * 1998-04-08 2000-07-18 International Business Machines Corporation High emittance electron source having high illumination uniformity
US8581481B1 (en) 2011-02-25 2013-11-12 Applied Physics Technologies, Inc. Pre-aligned thermionic emission assembly

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2291864A (en) * 1941-06-28 1942-08-04 Electronic Res Corp Electric discharge device
FR1485124A (fr) * 1965-06-30 1967-06-16 Siemens Ag Canon électronique pour tubes électroniques
FR1518363A (fr) * 1966-05-23 1968-03-22 Ibm Cathodes réfractaires à longue vie
NL153018B (nl) * 1967-02-17 1977-04-15 Philips Nv Indirect verhitte kathode.
US3569768A (en) * 1968-11-21 1971-03-09 Sylvania Electric Prod Cathode sleeve effecting maximum heat transfer to top of cathode cap and minimum to cap wall
DE2134513A1 (de) * 1971-07-10 1973-01-25 Westinghouse Electric Corp Elektronen emittierende quelle mit einem kathodenelement sowie einer anordnung zur aufheizung des kathodenelementes
US3914638A (en) * 1972-05-24 1975-10-21 Gte Sylvania Inc Cathode structure for cathode ray tube
JPS4929969A (fr) * 1972-07-20 1974-03-16
DE2313911B2 (de) * 1973-03-20 1975-09-25 Standard Elektrik Lorenz Ag, 7000 Stuttgart Schnell anheizende Kathode für Kathodenstrahlröhren
DE2317446C3 (de) * 1973-04-06 1983-11-10 Standard Elektrik Lorenz Ag, 7000 Stuttgart Verfahren zum Herstellen eines Heizelementes für eine indirekt geheizte Kathode
DE2317445C3 (de) * 1973-04-06 1982-09-09 Standard Elektrik Lorenz Ag, 7000 Stuttgart Verfahren zum Herstellen eines Heizkörpers für eine indirekt geheizte Kathode
DE2364403C3 (de) * 1973-12-22 1978-06-08 Standard Elektrik Lorenz Ag, 7000 Stuttgart Verfahren zum Herstellen eines Heizkörpers für eine indirekt geheizte Kathode
DE2654553A1 (de) * 1976-12-02 1978-06-08 Standard Elektrik Lorenz Ag Kathode fuer kathodenstrahlroehren
DE2938248A1 (de) * 1979-09-21 1981-03-26 Standard Elektrik Lorenz AG, 70435 Stuttgart Heizelement fuer eine indirekt geheizte kathode

Also Published As

Publication number Publication date
EP0045932A2 (fr) 1982-02-17
DE3174562D1 (en) 1986-06-12
EP0045932A3 (en) 1982-06-09
FI812424L (fi) 1982-02-08
US4401919A (en) 1983-08-30
FI71853C (fi) 1987-02-09
CA1182165A (fr) 1985-02-05
FI71853B (fi) 1986-10-31
DE3029853A1 (de) 1982-02-18
JPS57118333A (en) 1982-07-23
DE3029853C2 (de) 1982-08-26

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