EP0130874A1 - Verfahren und Vorrichtung zum Erwärmen der Elektroden oder elektrostatischen Linsen einer Elektronenkanone einer Kathodenstrahlröhre während deren Herstellung - Google Patents

Verfahren und Vorrichtung zum Erwärmen der Elektroden oder elektrostatischen Linsen einer Elektronenkanone einer Kathodenstrahlröhre während deren Herstellung 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
Authority
EP
European Patent Office
Prior art keywords
grid
voltage
cathode
generator
order
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.)
Withdrawn
Application number
EP84401222A
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English (en)
French (fr)
Inventor
Giuliano Giudici
Domenico Quaresima
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.)
Videocolor SA
Original Assignee
Videocolor 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 Videocolor SA filed Critical Videocolor SA
Publication of EP0130874A1 publication Critical patent/EP0130874A1/de
Withdrawn legal-status Critical Current

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Classifications

    • 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 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
EP84401222A 1983-06-24 1984-06-14 Verfahren und Vorrichtung zum Erwärmen der Elektroden oder elektrostatischen Linsen einer Elektronenkanone einer Kathodenstrahlröhre während deren Herstellung Withdrawn EP0130874A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8310503A FR2547951B1 (fr) 1983-06-24 1983-06-24 Procede et appareil de chauffage des electrodes ou lentilles electrostatiques d'un canon a electrons d'un tube a rayons cathodiques au cours de sa fabrication
FR8310503 1983-06-24

Publications (1)

Publication Number Publication Date
EP0130874A1 true EP0130874A1 (de) 1985-01-09

Family

ID=9290158

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84401222A Withdrawn EP0130874A1 (de) 1983-06-24 1984-06-14 Verfahren und Vorrichtung zum Erwärmen der Elektroden oder elektrostatischen Linsen einer Elektronenkanone einer Kathodenstrahlröhre während deren Herstellung

Country Status (3)

Country Link
EP (1) EP0130874A1 (de)
JP (1) JPS6014728A (de)
FR (1) FR2547951B1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2583919A1 (fr) * 1985-06-21 1986-12-26 Videocolor Procede et appareil de chauffage des electrodes d'un canon a electrons au cours de sa fabrication

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 (fr) * 1975-06-27 1977-02-04 Rca Corp Procede de traitement electrique de tubes cathodiques assembles
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 (fr) * 1975-06-27 1977-02-04 Rca Corp Procede de traitement electrique de tubes cathodiques assembles
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 (fr) * 1985-06-21 1986-12-26 Videocolor Procede et appareil de chauffage des electrodes d'un canon a electrons au cours de sa fabrication
EP0206927A1 (de) * 1985-06-21 1986-12-30 Videocolor Verfahren zur Heizung von Elektroden eines Elektronenstrahlerzeugers während seiner Herstellung
US4687454A (en) * 1985-06-21 1987-08-18 Videocolor Method and device for heating the electrodes of an electron gun during its manufacture

Also Published As

Publication number Publication date
FR2547951A1 (fr) 1984-12-28
JPS6014728A (ja) 1985-01-25
FR2547951B1 (fr) 1985-10-11

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

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Effective date: 19861218

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Inventor name: QUARESIMA, DOMENICO

Inventor name: GIUDICI, GIULIANO