EP0130874A1 - Method and apparatus for heating the electrodes or electrostatic lenses of a cathode ray tube gun during its manufacture - Google Patents

Method and apparatus for heating the electrodes or electrostatic lenses of a cathode ray tube gun during its manufacture Download PDF

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Publication number
EP0130874A1
EP0130874A1 EP84401222A EP84401222A EP0130874A1 EP 0130874 A1 EP0130874 A1 EP 0130874A1 EP 84401222 A EP84401222 A EP 84401222A EP 84401222 A EP84401222 A EP 84401222A EP 0130874 A1 EP0130874 A1 EP 0130874A1
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Prior art keywords
grid
voltage
cathode
generator
order
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German (de)
French (fr)
Inventor
Giuliano Giudici
Domenico Quaresima
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Videocolor SA
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Videocolor SA
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    • 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
    • H01J9/44—Factory adjustment of completed discharge tubes or lamps to comply with desired tolerances
    • H01J9/445—Aging of tubes or lamps, e.g. by "spot knocking"

Definitions

  • the invention relates to a method and an apparatus for heating the electrodes or lenses of the electron gun (s) of a cathode ray tube, in particular for color television, during its manufacture.
  • a television tube or, in general, a cathode ray tube comprises one or more electron guns intended to produce one or more beams of excitation of the luminescent substances forming the screen of the tube.
  • the electron gun comprises, on the one hand, an emissive cathode heated by a filament and, on the other hand, a set of electrodes and electrostatic lenses, generally called grids, namely: an electrode or Wehnelt G 1 brought to a variable potential, usually negative with respect to the cathode to control the extraction of electrons, in particular their quantity, a second electrode G 2 for acceleration of the electron beam and two electrostatic lenses G 3 and G 4 for concentration of the electron beam electrons.
  • This barrel is arranged at the rear of the vacuum interrupter that constitutes the tube itself.
  • the cathode (s) are heated to a temperature higher than the usual operating temperature in order to form and stabilize the material forming this cathode and then apply voltages to the grids to clean the tube, that is to say to remove unwanted gaseous particles which are absorbed by a pellet called getter.
  • such cleaning consists in sparking: application of a high voltage, of the order of 50 KV, between the grid G 4 and the other grids or cathode which are grounded and, on the other hand, by heating the various grids.
  • heatings are carried out in several stages; during one of these, a current of high intensity, at low voltage, is produced between the cathode and the grid G 2 , this current not only making it possible to heat the grid G 2 but also contributing to eliminating the gases in the tube.
  • a voltage is applied between the cathode and the gate G3 so as to produce a heating current from this gate G 3 .
  • a voltage generator which applies a potential difference between the cathode and the grid.
  • the output of this generator is often connected to the grid via a low-value resistor whose purpose is to limit the intensity of the current absorbed in the event of a short circuit.
  • the heating filament of the cathode is supplied. In this way an electric current flows between the cathode and the grid - thus constituting an anode - which heats this anode in order to perform a degassing or cleaning.
  • the parameters of the supply circuit are chosen so that the intensity of the current between the cathode and the anode is practically insensitive to variations in the dimensions of the cathode and of the grids as well as to the variations in distances between cathode and grid.
  • the heating power of the anode is also practically constant. This power is chosen in such a way that the temperature reached by the grid remains above a determined threshold.
  • a generator 11 of voltage V is used whose terminal 12 of higher potential is connected, via a resistor 13 of value R, to said grid 10 then constituting an anode, and the terminal 14 of the lowest potential of this generator 11, generally grounded, is connected to the cathode 15 and the heating filament 16 of this cathode is supplied with current.
  • sufficiently high values of the voltage V and of the resistance 13 are chosen so that the variations of the value r of the dynamic resistance between cathode 15 and anode 10 have little influence on the intensity of the current in the circuit.
  • V and R are chosen sufficiently high so that, taking into account the dispersion over the values of the dynamic resistance r, the heating power always retains a value sufficient to effect correct degassing.
  • the values V and R are such that, even for the greatest possible value of r, taking into account the dispersion, the intensity 1 of the current is sufficient for cleaning, these various values being linked by the relation:
  • the heating power supplied to the anode 10 is also practically independent of the variations in dimensions of the cathode 15 and of the anode 10 and of the distance between cathode 15 and anode 10. It is also possible to use the same assembly with generator 11 and resistance 13 to treat tubes of different types, that is to say tubes in which the dimensions of the cathode 15 and of the anodes 10 as well as the cathode-anode distances are various.
  • the resistor 13 has a value of the same order of magnitude as the average value r of the dynamic resistance between cathode 15 and anode 10.
  • a first example is the so-called "low voltage extraction” treatment. It consists in applying, in the previously known method, to the grid G 2 of an electron gun a voltage between 300 and 400 volts, the resistance in series with the generator having a value between 2.5 and 5 K ⁇ In this case the treatment varies from one tube to another and does not always give satisfactory results.
  • a generator 11 is used producing a voltage of the order of 800 to 900 volts (or 850 volts) and the value R of the resistor 13 is, for example, between 31 and 39 K ⁇ or between 30 and 40 K ⁇ . In this case the results obtained are much more satisfactory, the heating power being much more constant.
  • This second example concerns the heating of the grid G 3 to clean it and avoid the aforementioned "after glow" defect.
  • a voltage generator of the order of 800 to 1000 volts which is connected, via a resistance of 39 K ⁇ to the gate G 3 .
  • Another voltage generator + 450 volts is connected to the grid G 2 via a resistance of 5 K ⁇ while the grid G and the cathode are grounded.
  • the treatment is very sensitive to variations in dimensions.
  • the invention provides for using a single voltage generator delivering a positive voltage of + 1840 volts (of the order of 1800 volts), the output 20 of which is connected, via a resistor 21 with a value of 39 K ⁇ (of the order of 40 K n) at grid G 3 .
  • the terminal 22 of the resistor 21 which is opposite the terminal 20 is connected, by a resistor 23, of value 470 K ⁇ to a terminal 24 connected directly to the gate G 2 .
  • This terminal 24 is connected to ground via a resistor 25 of value 350 K ⁇ .
  • the cathode K and the gate G 1 are, as in the known method, connected to ground.
  • the heating power of the grid G 3 is much more constant than with the arrangement of the known method.
  • the stabilization of the power dissipated on the grid G 3 contributes, in this embodiment, the stabilization of the potential of the grid G 2 .

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)

Abstract

During manufacture of a cathode ray tube a grid (electrode or electrostatic lens) of an electron gun disposed in this vacuum tube, is heated. For this purpose, using a generator (11) a specified voltage is applied between the cathode (15) of the gun and the grid (10) so as to generate a current for heating this grid. The parameters of the power circuit are such that the intensity of the current is practically insensitive to the dimensional variations in the cathode (15) and in the grid (10) and to the variations in distance between cathode and grid, so that the temperature reached by the grid remains above a specified threshold. <IMAGE>

Description

L'invention est relative à un procédé et à un appareil de chauffage des électrodes ou lentilles du (ou des) canon(s) à électrons d'un tube à rayons cathodiques, notamment pour la télévision en couleurs, au cours de sa fabrication.The invention relates to a method and an apparatus for heating the electrodes or lenses of the electron gun (s) of a cathode ray tube, in particular for color television, during its manufacture.

On sait qu'un tube de télévision ou, de façon générale, un tube à rayons cathodiques, comprend un ou plusieurs canons à électrons destinés à produire un ou plusieurs faisceaux d'excitation des substances luminescentes formant l'écran du tube.It is known that a television tube or, in general, a cathode ray tube, comprises one or more electron guns intended to produce one or more beams of excitation of the luminescent substances forming the screen of the tube.

Le canon à électrons comprend, d'une part, une cathode émissive chauffée par un filament et, d'autre part, un ensemble d'électrodes et lentilles électrostatiques, généralement appelées grilles, à savoir : une électrode ou Wehnelt G1 portée à un potentiel variable, habituellement négatif par rapport à la cathode pour commander l'extraction des électrons, notamment leur quantité, une seconde électrode G2 d'accélération du faisceau d'électrons et deux lentilles électrostatiques G3 et G4 de concentration du faisceau d'électrons.The electron gun comprises, on the one hand, an emissive cathode heated by a filament and, on the other hand, a set of electrodes and electrostatic lenses, generally called grids, namely: an electrode or Wehnelt G 1 brought to a variable potential, usually negative with respect to the cathode to control the extraction of electrons, in particular their quantity, a second electrode G 2 for acceleration of the electron beam and two electrostatic lenses G 3 and G 4 for concentration of the electron beam electrons.

Ce canon est disposé à l'arrière de l'ampoule sous vide que constitue le tube proprement dit.This barrel is arranged at the rear of the vacuum interrupter that constitutes the tube itself.

Au cours de la fabrication du tube, après l'installation du canon dans l'ampoule et la mise sous vide de cette dernière, on chauffe la (ou les) cathode(s) à une température supérieure à la température habituelle de fonctionnement afin de former et stabiliser le matériau formant cette cathode et on applique ensuite aux grilles des tensions destinées à nettoyer le tube, c'est-à-dire à éliminer les particules gazeuses indésirables qui sont absorbées par une pastille appelée getter. Un tel nettoyage consiste, d'une part, en un étincelage : application d' une tension élevée, de l'ordre de 50 KV, entre la grille G4 et les autres grilles ou cathode qui sont à la masse et, d'autre part, en des chauffages des diverses grilles. Ces chauffages s'effectuent en plusieurs étapes; au cours de l'une de celles-ci on produit un courant d'intensité importante, à basse tension, entre la cathode et la grille G2, ce courant permettant non seulement de chauffer la grille G2 mais contribuant aussi à éliminer les gaz dans le tube. Au cours d'une autre étape on applique une tension entre la cathode et la grille G3 de façon à produire un courant de chauffage de cette grille G3.During the manufacture of the tube, after the installation of the barrel in the bulb and the evacuation of the latter, the cathode (s) are heated to a temperature higher than the usual operating temperature in order to form and stabilize the material forming this cathode and then apply voltages to the grids to clean the tube, that is to say to remove unwanted gaseous particles which are absorbed by a pellet called getter. On the one hand, such cleaning consists in sparking: application of a high voltage, of the order of 50 KV, between the grid G 4 and the other grids or cathode which are grounded and, on the other hand, by heating the various grids. These heatings are carried out in several stages; during one of these, a current of high intensity, at low voltage, is produced between the cathode and the grid G 2 , this current not only making it possible to heat the grid G 2 but also contributing to eliminating the gases in the tube. In another step, a voltage is applied between the cathode and the gate G3 so as to produce a heating current from this gate G 3 .

Pour ces chauffages de grilles on utilise un générateur de tension qui applique une différence de potentiel entre la cathode et la grille. La sortie de ce générateur est souvent connectée à la grille par l'intermédiaire d'une résistance de faible valeur dont le but est de limiter l'intensité du courant absorbé en cas de court-circuit. En même temps, on alimente le filament de chauffage de la cathode. De cette manière un courant électrique circule entre la cathode et la grille - constituant alors une anode - qui chauffe cette anode afin d'effectuer un dégazage ou nettoyage.For these grid heaters a voltage generator is used which applies a potential difference between the cathode and the grid. The output of this generator is often connected to the grid via a low-value resistor whose purpose is to limit the intensity of the current absorbed in the event of a short circuit. At the same time, the heating filament of the cathode is supplied. In this way an electric current flows between the cathode and the grid - thus constituting an anode - which heats this anode in order to perform a degassing or cleaning.

Les inventeurs ont constaté qu'avec ce procédé connu on n'obtenait pas toujours des résultats satisfaisants, c'est-à-dire que le nettoyage ou dégazage n'avait pas toujours la qualité requise. En particulier sur une même chaîne de fabrication de tubes certains de ceux-ci peuvent présenter le défaut appelé couramment "after glow", qui se traduit par une émission lumineuse de l'écran pendant un temps non négligeable après la mise hors tension du récepteur de télévision équipé du tube.The inventors have found that with this known process, satisfactory results are not always obtained, that is to say that the cleaning or degassing does not always have the required quality. In particular on the same tube production line, some of these tubes may have the defect commonly called "after glow", which results in a light emission from the screen for a non-negligible time after the receiver is switched off. television with tube.

Les études effectuées par les inventeurs ont montré que l'origine de ce défaut est la suivante : même pour des tubes en principe identiques les dimensions des diverses cathodes et grilles varient d'un tube à un autre en raison des dispersions inévitables pour une fabrication en grande série ; de même les distances entre la cathode et les diverses grilles ne sont pas constantes. Il résulte de cette observation que, le générateur, délivrant une tension constante, le courant produit n'a pas une intensité constante; ainsi la puissance appliquée sur l'anode à chauffer n'est pas constante et celle-ci peut être inférieure à la valeur qui permet un nettoyage efficace, la température atteinte étant trop basse.The studies carried out by the inventors have shown that the origin of this defect is as follows: even for tubes which are in principle identical, the dimensions of the various cathodes and grids vary from one tube to another due to the inevitable dispersions for manufacturing in large series; similarly the distances between the cathode and the various grids are not constant. It follows from this observation that, the generator, delivering a constant voltage, the current produced does not have a constant intensity; so the the power applied to the anode to be heated is not constant and this may be less than the value which allows effective cleaning, the temperature reached being too low.

Pour remédier à cet inconvénient, selon l'invention, on choisit les paramètres du circuit d'alimentation de façon telle que l'intensité du courant entre cathode et anode soit pratiquement insensible aux variations de dimensions de la cathode et des grilles ainsi qu'aux variations de distances entre cathode et grille. De cette manière la puissance de chauffage de l'anode est également pratiquement constante. Cette puissance est choisie de façon telle que la température atteinte par la grille reste supérieure à un seuil déterminé.To overcome this drawback, according to the invention, the parameters of the supply circuit are chosen so that the intensity of the current between the cathode and the anode is practically insensitive to variations in the dimensions of the cathode and of the grids as well as to the variations in distances between cathode and grid. In this way the heating power of the anode is also practically constant. This power is chosen in such a way that the temperature reached by the grid remains above a determined threshold.

Lorsque qu'une résistance est en série avec le générateur, pour s'affranchir desdites variations, il est avantageux de conférer une valeur élevée à la tension du générateur et à la résistance en série. En effet, dans ce cas, les variations de valeur de la résistance dynamique entre cathode et anode influent dans une faible mesure sur l'intensité du courant électrique de chauffage de l'anode. Il n'est cependant pas indispensable que la résistance en série soit de grande valeur par rapport à ladite résistance dynamique. On a, en effet, constaté qu'il suffit que cette résistance en série soit du même ordre de grandeur que la résistance dynamique moyenne entre cathode et anode pour que la puissance (et donc la température) de chauffage reste au-dessus du seuil en-dessous duquel le nettoyage est inefficace.When a resistor is in series with the generator, to overcome these variations, it is advantageous to give a high value to the generator voltage and to the resistor in series. In this case, the variations in the value of the dynamic resistance between the cathode and the anode have a small influence on the intensity of the electric heating current of the anode. However, it is not essential that the series resistance be of great value compared to said dynamic resistance. We have, in fact, found that it is sufficient for this series resistance to be of the same order of magnitude as the average dynamic resistance between cathode and anode for the heating power (and therefore the temperature) to remain above the threshold in - below which cleaning is ineffective.

D'autres caractéristiques et avantages de l'invention apparaîtront avec la description de certains de ses modes de réalisation, celle-ci étant effectuée en se référant aux dessins ci-annexés sur lesquels :

  • - la figure 1 est un schéma servant à illustrer le procédé de l'invention, et
  • - la figure 2 est le schéma d'un circuit utilisable pour le chauffage des grilles G3 et G2 d'un tube de télévision en couleurs.
Other characteristics and advantages of the invention will appear with the description of some of its embodiments, this being carried out with reference to the attached drawings in which:
  • FIG. 1 is a diagram used to illustrate the process of the invention, and
  • - Figure 2 is a diagram of a circuit usable for heating the grids G 3 and G 2 of a color television tube.

Pour chauffer une grille 10 (électrode ou lentille électrostatique) d'un canon à électrons - non représenté en détail - d'un tube de télévison, après l'installation de ce dernier dans l'ampoule de verre (également non représentée) et la mise sous vide de cette ampoule, on utilise un générateur 11 de tension V dont la borne 12 de plus haut potentiel est reliée, par l'intermédiaire d'une résistance 13 de valeur R, à ladite grille 10 constituant alors une anode, et on connecte la borne 14 de plus bas potentiel de ce générateur 11, généralement à la masse, à la cathode 15 et on alimente en courant le filament 16 de chauffage de cette cathode. On a ainsi affaire à un circuit fermé grâce aux électrons produits par la cathode 15 vers l'anode 10.To heat a grid 10 (electrode or electrostatic lens) of an electron gun - not shown in detail - of a television tube, after the installation of the latter in the bulb of glass (also not shown) and the vacuuming of this bulb, a generator 11 of voltage V is used whose terminal 12 of higher potential is connected, via a resistor 13 of value R, to said grid 10 then constituting an anode, and the terminal 14 of the lowest potential of this generator 11, generally grounded, is connected to the cathode 15 and the heating filament 16 of this cathode is supplied with current. We are thus dealing with a closed circuit thanks to the electrons produced by the cathode 15 towards the anode 10.

Selon l'invention on choisit des valeurs suffisamment élevées de la tension V et de la résistance 13 pour que les variations de la valeur r de la résistance dynamique entre cathode 15 et anode 10 aient une faible influence sur l'intensité du courant dans le circuit. De façon plus précise on choisit V et R de façon suffisamment élevée pour que, compte tenu de la dispersion sur les valeurs de la résistance dynamique r, la puissance de chauffage garde toujours une valeur suffisante pour effectuer un dégazage correct. Autrement dit les valeurs V et R sont telles que, même pour la plus grande valeur possible de r, compte tenu de la dispersion, l'intensité 1 du courant soit suffisante pour le nettoyage, ces diverses valeurs étant liées par la relation :

Figure imgb0001
De cette manière, comme déjà mentionné ci-dessus, la puissance de chauffage apportée à l'anode 10 est également pratiquement indépendante des variations de dimensions de la cathode 15 et de l'anode 10 et de la distance entre cathode 15 et anode 10. On peut aussi utiliser le même montage à générateur 11 et résistance 13 pour traiter des tubes de types différents, c'est-à-dire des tubes dans lesquels les dimensions de la cathode 15 et des anodes 10 ainsi que les distances cathode-anode sont diverses.According to the invention, sufficiently high values of the voltage V and of the resistance 13 are chosen so that the variations of the value r of the dynamic resistance between cathode 15 and anode 10 have little influence on the intensity of the current in the circuit. . More precisely, V and R are chosen sufficiently high so that, taking into account the dispersion over the values of the dynamic resistance r, the heating power always retains a value sufficient to effect correct degassing. In other words the values V and R are such that, even for the greatest possible value of r, taking into account the dispersion, the intensity 1 of the current is sufficient for cleaning, these various values being linked by the relation:
Figure imgb0001
 In this way, as already mentioned above, the heating power supplied to the anode 10 is also practically independent of the variations in dimensions of the cathode 15 and of the anode 10 and of the distance between cathode 15 and anode 10. It is also possible to use the same assembly with generator 11 and resistance 13 to treat tubes of different types, that is to say tubes in which the dimensions of the cathode 15 and of the anodes 10 as well as the cathode-anode distances are various.

L'expérience a montré que pour s'affranchir desdites variations il peut suffire que la résistance 13 ait une valeur du même ordre de grandeur que la valeur moyenne r de la résistance dynamique entre cathode 15 et anode 10.Experience has shown that to overcome these variations it may suffice that the resistor 13 has a value of the same order of magnitude as the average value r of the dynamic resistance between cathode 15 and anode 10.

Pour montrer l'intérêt de l'invention on décrit ci-après des expériences de comparaison entre le procédé connu et le procédé de l'invention.In order to show the advantage of the invention, experiments of comparison between the known method and the method of the invention are described below.

Un premier exemple est le traitement dit "d'extraction" à basse tension. Il consiste à appliquer, dans le procédé antérieurement connu, sur la grille G2 d'un canon à électrons une tension comprise entre 300 et 400 volts, la résistance en série avec le générateur ayant une valeur comprise entre 2,5 et 5 K Ω.Dans ce cas le traitement varie d'un tube à un autre et ne donne pas toujours des résultats satisfaisants.A first example is the so-called "low voltage extraction" treatment. It consists in applying, in the previously known method, to the grid G 2 of an electron gun a voltage between 300 and 400 volts, the resistance in series with the generator having a value between 2.5 and 5 K Ω In this case the treatment varies from one tube to another and does not always give satisfactory results.

Avec le procédé de l'invention on utilise un générateur 11 produisant une tension de l'ordre de 800 à 900 volts (ou 850 volts) et la valeur R de la résistance 13 est, par exemple, comprise entre 31 et 39 KΩ ou entre 30 et 40 KΩ . Dans ce cas les résultats obtenus sont beaucoup plus satisfaisants, la puissance de chauffage étant beaucoup plus constante.With the method of the invention, a generator 11 is used producing a voltage of the order of 800 to 900 volts (or 850 volts) and the value R of the resistor 13 is, for example, between 31 and 39 KΩ or between 30 and 40 KΩ. In this case the results obtained are much more satisfactory, the heating power being much more constant.

Un second exemple est décrit en relation avec la figure 2.A second example is described in relation to Figure 2.

Ce second exemple concerne le chauffage de la grille G3 pour la nettoyer et éviter le défaut, susmentionné, d"'after glow".This second example concerns the heating of the grid G 3 to clean it and avoid the aforementioned "after glow" defect.

Dans le procédé connu on utilise un générateur de tension de l'ordre de 800 à 1000 volts qui est relié, par l'intermédiaire d'une résistance de 39 KΩ à la grille G3. Un autre générateur de tension + 450 volts est relié à la grille G2 par l'intermédiaire d'une résistance de 5 K Ω tandis que la grille G et la cathode sont à la masse. Là également le traitement est très sensible aux variations de dimensions.In the known method, a voltage generator of the order of 800 to 1000 volts is used which is connected, via a resistance of 39 KΩ to the gate G 3 . Another voltage generator + 450 volts is connected to the grid G 2 via a resistance of 5 K Ω while the grid G and the cathode are grounded. Here too, the treatment is very sensitive to variations in dimensions.

Pour ce traitement, l'invention prévoit d'utiliser un unique générateur de tensions délivrant une tension positive de + 1840 volts (de l'ordre de 1800 volts), dont la sortie 20 est reliée, par l'intermédiaire d'une résistance 21 de valeur 39 KΩ (de l'ordre de 40 K n ) à la grille G3. La borne 22 de la résistance 21 qui est opposée à la borne 20 est connectée, par une résistance 23, de valeur 470 KΩ à une borne 24 connectée directement à la grille G2. Cette borne 24 est reliée à la masse par l'intermédiaire d'une résistance 25 de valeur 350 KΩ . Dans ce montage (qui fait appel à un diviseur de tensions à résistances 21, 23 et 25) la cathode K et la grille G 1 sont, comme dans le procédé connu, reliées à la masse. Avec ce montage la puissance de chauffage de la grille G3 est beaucoup plus constante qu'avec le montage du procédé connu. A la stabilisation de la puissance dissipée sur la grille G3 contribue, dans cette réalisation, la stabilisation du potentiel de la grille G2.For this treatment, the invention provides for using a single voltage generator delivering a positive voltage of + 1840 volts (of the order of 1800 volts), the output 20 of which is connected, via a resistor 21 with a value of 39 KΩ (of the order of 40 K n) at grid G 3 . The terminal 22 of the resistor 21 which is opposite the terminal 20 is connected, by a resistor 23, of value 470 KΩ to a terminal 24 connected directly to the gate G 2 . This terminal 24 is connected to ground via a resistor 25 of value 350 KΩ. In this arrangement (which uses a voltage divider with resistors 21, 23 and 25) the cathode K and the gate G 1 are, as in the known method, connected to ground. With this arrangement, the heating power of the grid G 3 is much more constant than with the arrangement of the known method. In this stabilization of the power dissipated on the grid G 3 contributes, in this embodiment, the stabilization of the potential of the grid G 2 .

Claims (6)

1. Procédé de chauffage d'une grille - électrode ou lentille électrostatique - d'un canon à électrons disposé dans un tube à rayons cathodiques sous vide, au cours de la fabrication de ce dernier, procédé dans lequel on applique, à l'aide d'un générateur (11), une tension déterminée entre la cathode (15) et la grille (10) de façon à engendrer un courant de chauffage de ladite grille, caractérisé en ce qu'on choisit les paramètres du circuit d'alimentation de façon telle que l'intensité du courant soit pratiquement insensible aux variations de dimensions de la cathode (15) et de la grille (10) et aux variations de distance entre cathode (15) et grille (10) afin que la température atteinte par la grille reste supérieure à un seuil déterminé.1. Method of heating a grid - electrode or electrostatic lens - of an electron gun placed in a cathode ray tube under vacuum, during the manufacture of the latter, method in which one applies, using of a generator (11), a determined voltage between the cathode (15) and the grid (10) so as to generate a heating current of said grid, characterized in that the parameters of the supply circuit of so that the intensity of the current is practically insensitive to variations in the dimensions of the cathode (15) and the grid (10) and to the variations in distance between cathode (15) and grid (10) so that the temperature reached by the grid remains above a determined threshold. 2. Procédé selon la revendication 1, caractérisé en ce qu'une résistance (13) étant en série avec le générateur (11), pour s'affranchir desdites variations, on choisit à une valeur suffisamment élevée la tension (V) du générateur (11) et la résistance (13).2. Method according to claim 1, characterized in that a resistor (13) being in series with the generator (11), to overcome said variations, the voltage (V) of the generator is chosen at a sufficiently high value ( 11) and the resistance (13). 3. Procédé selon la revendication 2, caractérisé en ce que ladite résistance (13) en série avec le générateur (11) de tension (V) a une valeur (R) du même ordre de grandeur que la résistance dynamique moyenne entre cathode (15) et grille (10).3. Method according to claim 2, characterized in that said resistor (13) in series with the voltage generator (11) (V) has a value (R) of the same order of magnitude as the average dynamic resistance between cathode (15 ) and grid (10). 4. Procédé selon la revendication 3, du type à application d'une basse tension, de l'ordre de 400 volts, sur la grille G2, caractérisé en ce que la tension du générateur (11) est de l'ordre de 850 volts et la valeur (R) de la résistance en série est de l'ordre de 30 à 40 Kn .4. Method according to claim 3, of the type applying a low voltage, of the order of 400 volts, on the grid G 2 , characterized in that the generator voltage (11) is of the order of 850 volts and the value (R) of the series resistance is of the order of 30 to 40 Kn. 5. Procédé selon la revendication 3, du type dans lequel une tension de l'ordre de 800 à 1000 volts est appliquée sur la grille G 39 caractérisé en ce que la tension (V) du générateur est de l'ordre de 1800 volts et la valeur de la résistance (21) en série est de l'ordre de 40 K n.5. Method according to claim 3, of the type in which a voltage of the order of 800 to 1000 volts is applied to the gate G 39 characterized in that the voltage (V) of the generator is of the order of 1800 volts and the value of the resistance (21) in series is of the order of 40 K n. 6. Appareil pour la mise en oeuvre du procédé selon les revendications 4 et 5, caractérisé en ce qu'il comprend un unique générateur de tensions (+ V) alimentant un diviseur de tensions à résistances (21, 23 et 25), les grilles G3 et G2 étant connectées à des prises distinctes (22, 24) de ce diviseur et le montage étant tel qu'à la stabilisation de l'intensité du courant de la grille G3 contribue la stabilité de la tension de la grille G2.6. Apparatus for implementing the method according to claims 4 and 5, characterized in that it comprises a single voltage generator (+ V) supplying a voltage divider to resistors (21, 23 and 25), the grids G 3 and G 2 being connected to separate sockets (22, 24) of this divider and the mounting being such as to stabilize the current intensity of the grid G 3 contributes to the stability of the voltage of the gate G 2 .
EP84401222A 1983-06-24 1984-06-14 Method and apparatus for heating the electrodes or electrostatic lenses of a cathode ray tube gun during its manufacture Withdrawn EP0130874A1 (en)

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FR8310503A FR2547951B1 (en) 1983-06-24 1983-06-24 METHOD AND APPARATUS FOR HEATING ELECTROSTATIC ELECTRODES OR LENSES OF AN ELECTRON CANON OF A CATHODE RAY TUBE DURING ITS MANUFACTURE
FR8310503 1983-06-24

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2583919A1 (en) * 1985-06-21 1986-12-26 Videocolor METHOD AND APPARATUS FOR HEATING ELECTRODES OF AN ELECTRON GUN DURING ITS MANUFACTURE

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1632074A (en) * 1927-06-14 X c control apparatus
US3736038A (en) * 1971-03-26 1973-05-29 Mitsubishi Kenki Kk Spot-knocking method for electronic tubes
FR2317761A1 (en) * 1975-06-27 1977-02-04 Rca Corp ELECTRICAL TREATMENT PROCESS OF ASSEMBLED CATHODIC TUBES
US4125306A (en) * 1977-11-17 1978-11-14 Rca Corporation Spiked low-voltage aging of cathode-ray tubes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1632074A (en) * 1927-06-14 X c control apparatus
US3736038A (en) * 1971-03-26 1973-05-29 Mitsubishi Kenki Kk Spot-knocking method for electronic tubes
FR2317761A1 (en) * 1975-06-27 1977-02-04 Rca Corp ELECTRICAL TREATMENT PROCESS OF ASSEMBLED CATHODIC TUBES
US4125306A (en) * 1977-11-17 1978-11-14 Rca Corporation Spiked low-voltage aging of cathode-ray tubes

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2583919A1 (en) * 1985-06-21 1986-12-26 Videocolor METHOD AND APPARATUS FOR HEATING ELECTRODES OF AN ELECTRON GUN DURING ITS MANUFACTURE
EP0206927A1 (en) * 1985-06-21 1986-12-30 Videocolor Method for heating electron gun electrodes during manufacture
US4687454A (en) * 1985-06-21 1987-08-18 Videocolor Method and device for heating the electrodes of an electron gun during its manufacture

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FR2547951A1 (en) 1984-12-28
FR2547951B1 (en) 1985-10-11

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