US3356436A - Gettering system for electron tubes - Google Patents

Gettering system for electron tubes Download PDF

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Publication number
US3356436A
US3356436A US405508A US40550864A US3356436A US 3356436 A US3356436 A US 3356436A US 405508 A US405508 A US 405508A US 40550864 A US40550864 A US 40550864A US 3356436 A US3356436 A US 3356436A
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United States
Prior art keywords
getter
tube
bulk
getter device
tubes
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Expired - Lifetime
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US405508A
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English (en)
Inventor
Porta Paolo Della
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SAES Getters SpA
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SAES Getters SpA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/94—Selection of substances for gas fillings; Means for obtaining or maintaining the desired pressure within the tube, e.g. by gettering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J7/00—Details not provided for in the preceding groups and common to two or more basic types of discharge tubes or lamps
    • H01J7/14—Means for obtaining or maintaining the desired pressure within the vessel
    • H01J7/18—Means for absorbing or adsorbing gas, e.g. by gettering
    • H01J7/186—Getter supports

Definitions

  • This'system is effected by means of a nonevaporating metal absorber, which in the specification andsubsequent claim-s will be indicated by the name bulk getter, and also by means'of a main absorber, indicated simply as ash getter, which is evaporable and preferably of the barium type.
  • the usual production technique for electron tubes is at the present time as follows: after depositing the phosphors, lacquering, aluminizing and/or graphitizing the tube, the gun is welded onto the neck and the tube is ready for the pumping process. It should be noted that the cost of screening the tube, especially in the case of a kinescope for color TV, may be as much as 50% of the total cost of the finished tube.
  • the tube is then -subjected to a normal pum-ping cycle, i.e. it is pumped, degassed, the cathode is processed and the tube sealed oi after which, normally, when the tube has cooled a ash getter contained within the tube itself is evaporated.
  • the function of the flash getter is that of further reducing the gas pressure in the tube after it has been sealed off, and also that of maintaining a low internal pressure for the entire life of the tube.
  • the getter generally used in such .tubes is a barium getter which, when ilashed, deposits on the entire inside surface of the tube, .with the exception of the gun, a thin film ⁇ of pure barium. lt is this film that acts as a pump for the tube. The greater the amount of barium deposited andthe greater the area of the film thus formed, the better will be the internal pumping action taking place in the tube.
  • the bulk getter will be especially advantageous if lpartially saturated with hydrogen which, on activation, is liberated within the electron tube in a controlled and known quantity, in such a way as to produce and maintain the conditions most favorable for the activation of the cathode and for the performance of the test.
  • the bulk getter used according to the present invention preferably includes metals or alloys of the elements Zr, Ti, H, Th, W, Mo, Nb, and especially such elements alloyed with aluminum.
  • the hydrogen content in the bulk getter is between 5 and 15 cc. torr/mg. of thealloy used in the bulk getter.
  • the main evaporable getter used in the tube can be any one of those commonly used having the essential characteristic of being able to evaporate barium over the largest possible area.
  • FIGS. 1, 2 and 3 represent three different dispositions of bulk getter mounting.
  • the bulk getter is indicated in the drawing with the numeral 1, with the main evaporable flash getter being indicated with the numeral 2.
  • the bulk getter which in the example illustrated has the form of a tablet
  • the main flash getter which according to known techniques is ring-shaped, are mounted in different positions in each of the three figures, but are always so disposed as to bring it about that the plane substantially containing the bulk getter is perpendicular to the plane containing the ring of the main flash getter, so that when one getter is activated by means of a high frequency coil, the eddy currents induced into the other getter will not suffice to activate it.
  • a flash getter consisting of a ring with an external diameter of 25 mm. and capable of supplying 100 mg. of evaporated barium, and there is also mounted a bulk getter having a surface area of 50 mm.2 and containing 500 cc. torr of hydrogen.
  • the bulk getter After having prepared the tube, after producing the vacuum, and after sealing off the said tube, the bulk getter only is activated. Despite the fact that the vacuum is only about 1x104t torr, a .good cathode activity was found.
  • the vacuum cannot be improved; however, the composition of the gas contained in the tube is of the nature necessary to maintain a good activity of the cathode.
  • the bulk getter used showed that it was suitable to keep the tube in good working condition for a long period of time. In fact, even ten days after activation of the bulk getter it was noted that the pressure had remained constant, and that the activity of the cathoderwas still good.
  • a method for the manufacture of an electron tube whereby deposition of a getter metal film on internal surfaces within the tube is avoided until after the tube has tested satisfactorily comprising in sequence the steps of mounting in said tube a first getter device and a second getter device said first getter device having a heat activatable nonvaporizing gas adsorptive getter material, and said second getter device having a getter metal which is evaporable under the inliuence of heat in a vacuum, sealing the tube, activating the first getter device and testing the tube whereby, if the tube tests satisfactorily, the getter metal in the second getter device is vaporized depositing itself in the form of a gas adsorbtive film on the internal surfaces within the tube.
  • a method as claimed in claim 1 comprising saturating the first getter device with hydrogen to enhance its effectiveness independently of the second getter device.
  • a method as claimed in claim 1 comprising mounting the getter devices in respective positions whereat only one getter device at a time can be activated by high-frequency heating.
  • a method for the manufacture of an electron tube whereby deposition of a getter metal film on internal surfaces Within the tube is avoided until after the tube has tested satisfactorily comprising in sequence the steps of mounting in said tube a first getter device and a second getter device said first getter device having a heat activatable nonvaporizing gas adsorptive getter material, and said second getter device having a getter metal which is evaporable under the influence of heat in a vacuum, sealing the tube, activating the first getter device and testing the tube whereby, if the tube tests unsatisfactorily the tube is opened to the atmosphere, repaired, sealed, tested, and if the tube then tests satisfactorily the getter metal in the second getter device is then vaporized.

Landscapes

  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US405508A 1964-04-11 1964-10-21 Gettering system for electron tubes Expired - Lifetime US3356436A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT793564 1964-04-11

Publications (1)

Publication Number Publication Date
US3356436A true US3356436A (en) 1967-12-05

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US405508A Expired - Lifetime US3356436A (en) 1964-04-11 1964-10-21 Gettering system for electron tubes

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US (1) US3356436A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1041356A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
IT (1) IT720119A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3408130A (en) * 1966-01-08 1968-10-29 Philips Corp Nonevaporative getter
US5508586A (en) * 1993-06-17 1996-04-16 Saes Getters S.P.A. Integrated getter device suitable for flat displays
EP0817234A1 (en) * 1996-06-24 1998-01-07 Motorola, Inc. Ultra-high vacuum field emission display
FR2771549A1 (fr) * 1996-05-29 1999-05-28 Futaba Denshi Kogyo Kk Recipient hermetique sous vide

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS49132972A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) * 1973-04-24 1974-12-20
US4398897A (en) 1981-07-28 1983-08-16 Rca Corporation Method of processing a cathode-ray tube for eliminating blocked apertures caused by charged particles
US4431939A (en) * 1981-07-28 1984-02-14 Rca Corporation Structure and method for eliminating blocked apertures caused by charged particles

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1752747A (en) * 1926-03-10 1930-04-01 Westinghouse Lamp Co Electron-discharge device and getter therefor
US1883174A (en) * 1927-12-12 1932-10-18 Electrons Inc Discharge tube fabrication

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1752747A (en) * 1926-03-10 1930-04-01 Westinghouse Lamp Co Electron-discharge device and getter therefor
US1883174A (en) * 1927-12-12 1932-10-18 Electrons Inc Discharge tube fabrication

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3408130A (en) * 1966-01-08 1968-10-29 Philips Corp Nonevaporative getter
US5508586A (en) * 1993-06-17 1996-04-16 Saes Getters S.P.A. Integrated getter device suitable for flat displays
FR2771549A1 (fr) * 1996-05-29 1999-05-28 Futaba Denshi Kogyo Kk Recipient hermetique sous vide
EP0817234A1 (en) * 1996-06-24 1998-01-07 Motorola, Inc. Ultra-high vacuum field emission display

Also Published As

Publication number Publication date
GB1041356A (en) 1966-09-07
IT720119A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

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