US3389288A - Gettering device including a getter metal and a gas releasing material - Google Patents

Gettering device including a getter metal and a gas releasing material Download PDF

Info

Publication number
US3389288A
US3389288A US482104A US48210465A US3389288A US 3389288 A US3389288 A US 3389288A US 482104 A US482104 A US 482104A US 48210465 A US48210465 A US 48210465A US 3389288 A US3389288 A US 3389288A
Authority
US
United States
Prior art keywords
getter
barium
tube
screen
gas
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
US482104A
Other languages
English (en)
Inventor
Porta Paolo Della
Tiziano A Giorgi
Rabusin Elio
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.)
SAES Getters SpA
Original Assignee
SAES Getters SpA
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 SAES Getters SpA filed Critical SAES Getters SpA
Priority to US664593A priority Critical patent/US3388955A/en
Application granted granted Critical
Publication of US3389288A publication Critical patent/US3389288A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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

Definitions

  • This invention relates to a process for producing within electron tubes, and in particular television picture tubes, a thin metallic film capable of sorbing their residual gases and characterized by the fact that its distribution is substantially limited to the desired surfaces of the tube and also by the fact that the film on the screen of the television picture tube is of reduced thickness, when compared to other conventionally produced films, and so presents less impedance to the flow of electrons directed at the phosphors on the screen of the tube.
  • the present invention also relates to the device to be employed to accomplish the above mentioned process.
  • the getter consists of a thin metallic film deposited on appropriate surfaces of the device after it has been processed and isolated from the conventional pumps. This thin metallic film is usually barium and is commonly deposited from a getter container which may be heated by externally induced radio frequency currents.
  • the getter container consists of a non-magnetic stainless steel ring of U shaped section in which is usually compressed in equal proportions a mixture of powdered 50% barium-50% aluminium alloy and nickel.
  • the barium film obtained from either of these two processes is very active chemically, it reacts with the residual gases present in the tube and efiiciently removes them from the gaseous phase. Furthermore, the action of the barium film is not instantaneous or short lived, but by means of diffusion phenomena it is capable of continuing its gettering or pumping action throughout the life of the tube.
  • the image on the screen of a television picture tube is due to the high energy electrons which impinge and ex cite suitable phosphors, evenly distributed on the internal surface of the screen.
  • To increase the luminescence of these phosphors in the forward direction it is standard practice to cover them, on the side from which the electrons are incident on them, by a thin layer of aluminum which has also other electrical functions connected with the potential distribution within the tube, the protection of the phosphors from ion burn, etc.
  • the presence of this aluminum film causes a loss in energy of the electrons which are directed at the phosphors and so decrease their luminosity.
  • the same effect is also caused by the barium present on the screen and although its thickness is much less than that of the aluminum its effects are more pronounced due to its higher molecular mass.
  • the thickness of the barium film is greatest at the center of the screen and it is here that electrons are decelerated to a greater extent. This sometimes causes the characteristic darker central portion. in the image on the screen and can only be avoided by using higher electron accelerating potentials in the design of the set with consequent increase in production costs.
  • bafiles are such as to direct the barium vapors towards the center of the bulb, i.e. on the normal to the center of the screen of the tube.
  • the coverage being so adjusted as to cause collisions between the barium atoms before they reach the screen and thus cause a virtual point source of barium atoms from which they may evaporate in all directions.
  • the container of the getter has bafiies which direct the evaporating barium atoms in a direction perpendicular to that of the normal to the center of the screen.
  • bafiies which direct the evaporating barium atoms in a direction perpendicular to that of the normal to the center of the screen.
  • the principal object of the present invention is to provide a means of reducing the quantity of barium reaching the screen of a television picture tube or similar device, if required even to zero, and to redistribute the excess barium on other internal surfaces which have up till now been less utilized, for example the cone area.
  • attempts are not made, as occurs with known conventional methods, to direct the barium atoms by means of baffles, but steps are taken to prevent large amounts, or even all of the barium, from reaching the screen of television picture tubes or similar devices by introducing a deviating or retarding mass in its way.
  • the invention relates essentially to exothermic type getters.
  • the process consists in providing a getter device which in spite of its inherent high rate of evaporation, and just because of this characteristic, provides within the volume in which it is evaporated a suitable deviating and retarding mass which avoids the otherwise predominant deposition of getter material in the forward direction.
  • the evaporation of the getter occurs in the presence of a suitable gas having an adequate molecular mass and present at a predetermined pressure so that the mean free path of the barium atoms in it is smaller than the distance between getter container and screen. It is also a characteristic of the invention that the gas used is repumped by the actual barium film, Without however, consuming but a very minute fraction of the films gettering capacity, in a very short interval of time. In fact it may be stated that the last barium to leave the getter container does not find in its way any gas and not being hindered can be deposited according to the known distribution laws.
  • the heating of the getter container can be stopped immediately after having initiated the exothermic reaction.
  • the gas employed be nitrogen, introduced into the tube in the form of a stable compound, which will dissociate only at temperatures immediately below the onset of the exothermic reaction and that the gas be present in the tube before the onset of such exothermic reaction.
  • the novelty of the invention rests in the fact that, a suitable choice of gas and pressure enables the control of up to 50% of the barium which may be obtained from an exothermic type getter without producing any fine particles and Without leaving a high pressure in the tube at the end of the evaporation process.
  • this fraction of the barium is deposited only in the cone and neck zones of the television picture tube, while the rest of the barium is evenly distributed on these and the remaining internal surface areas of the tube. Should no barium be required on the screen this result can also :be obtained by interrupting the heating of the getter container once having initiated the exothermic reaction.
  • the rare gases such as argon, krypton, etc.
  • these gases are not sorbed by the getter material and so if the getter film is deposited, as occurs usually, in the closed tube the rare gases would remain in it rendering its functioning impossible. Therefore, such gases may not be utilized for the purposes of the present invention.
  • Other gases such as hydrogen, carbon monoxide, carbon dioxide and oxygen may be considered.
  • such gases would be extremely detrimental to tube characteristics as such and also because they tend to produce hydrocarbons, water vapor, etc., which are harmful to cathode activity.
  • a high pressure would be necessary due to its particularly low mass.
  • a high pressure would be necessary to cope with the extremely high reaction rates which they present with pure barium films.
  • the gas 'which to the ends of the present invention has resulted as the most suitable is nitrogen.
  • this gas does not damage the cathode, does not produce undesirable side products, it has a relatively high mass, it is not exceedingly reactive with barium, although it is easily sorbed by it, and as a consequence the pressure necessary to obtain the desired effect is rather low.
  • the nitrogen pressure which has proven to be most satisfactory for the scope of the present invention is of the order of between 5X10 and 1X10 torr. Pressures above 5x101: torr using up too great a fraction of the barium film and pressures below 10- torr not being sufficient to the scope of the present invention.
  • the introduction of the selected gas into the tube may occur in a number of ways. One of these could be to introduce the required pressure in the tube while still on the pump and just before tip-off. However, such a method would not be technically economical.
  • a compound of nitrogen which will be dissociated by heating prior to evaporation of the barium.
  • Such a compound could be in powdered form and be mixed in the correct proportions with the getter alloy in the container, it could also be mounted on a separate support removed from the getter, and it may even be that the actual getter container has been subjected to a nitrogenating action giving rise to suitable compounds.
  • the compound employed must be stable to all possible aging and pretreatments such as deionized Water wash, drying and vacuum heat treatments up to 400 C.
  • the compound used should, if mounted in the getter container, dissociate at temperatures below the one at which the exothermic reaction set in.
  • barium azide for example has been long known, with other finalities of those explained in the present invention, however, barium azide would not be usable since its extreme instability to aging under normal atmosphere conditions or to heating under vacuum are well known.
  • Non-limiting examples of compounds suitable to this end in the present invention are those obtained from nitrogen and any of the following metals or alloys thereof: nickel, iron, molybdenum, manganese, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, tungsten, cobalt, silicon and stainless steel.
  • the nitrogen bearing compound may be mixed with the exothermic charge in the getter container, it may be physically separated from it and thus the gas it contains may be evolved a priori before heating the getter container or the getter container itself may be nitrogenated.
  • the principle of the invention although essentially for exothermic getters, cannot be excluded from use in endothermic getters. However, since in this case the evaporation is initially low and then picks up speed the quantity of gas must be initially low and must slowly increase as the rate of evaporation rises. In the case of exothermic getters since, as previously mentioned, 30 to 40% of the barium is emitted simultaneously and at the same time, the nitrogen pressure present has full effect on this quantity of barium. The remaining barium which evaporates at a slower rate is less influenced due to the sorption of nitrogen which has taken place. Nevertheless an appreciable influence is also exercised on this second quantity of barium.
  • the exothermic getter containing the nitrogenous compound most suitable, and having any desired or suitable deflecting baffles arrangement can be mounted as the normal and more conventional getter on the electron gun of the tube or in any required or desired position.
  • the usefulness of the bafiles is, however, very limited in the getters of the present invention as far as regards the barium film distribution on the screen and on the cone of the television picture tube. Their action is still useful as far as regards back evaporation of barium towards the gun of the tube.
  • An 11-inch television picture tube having a flare angle of 110 is used in conjunction with a conventional getter mounted 1 from.
  • the yoke reference line (Y.R.L.) consisting of a powdered mixture of equal proportion of 50% Ba-50% metal alloy and nickel supported in a stainless steel container of ring shape.
  • the getter is evaporated under good vacuum conditions producing the distribution of barium in the tube indicated in FIG. 1 which shows schematically a section of the tube together with two Diagrams a and 12. These diagrams refer to the barium thickness on the screen a and cone b sections of the tube. In each diagram the dashed lines, indicated by 1 and 3, refer to the above-mentioned type of getter.
  • the thickness of the film at the centre of the screen is 1400 Angstrom units.
  • Fe N powdered iron nitride
  • the barium film distribution in the tube is shown by the continuous lines in the Diagrams a and b of FIG. 1 indicated by 2 and 4. It will be noted that the thickness of the barium film at the centre of the screen is less than 400 Angstrom units in this case.
  • the relative quantities of barium on the screen, cone and neck of the tube with conventional getters are respectively 7.0, 1.8, and 16.2 mg. and with the getters object of the present invention they are respectively 2.5, 3.5 and 19 mg.
  • Such significant reduction of barium on the screen is very useful for electron transparence and results in an increased light output from the tube of up to 30%.
  • FIG. 2 The fact that evaporation of the barium film in a nitrogen atmosphere in no way reduces the characteristics of the barium film produced is illustrated in FIG. 2.
  • the gettering rates of carbon monoxide whilst on the abscissae are reported the related quantities of carbon monoxide sorbed.
  • the television picture tube and getter types as well as position are the same as those previously mentioned.
  • the gettering characteristics were, also in this case, measured for a 25 mg.
  • Ba film and the constant CO pressure on the getter was 5 x 10- torr.
  • Curve 5 refers to the characteristics of a conventional getter film while curve 6 refers to those of a film obtained according to the present invention.
  • FIG. 3 clearly shows the retarding action of the gas introduced on the forward evaporation of barium.
  • Such curves have been obtained by using a quartz crystal thickness monitor.
  • the crystal is mounted on a tube similar to the one above at the centre of the screen.
  • Its shift of frequency as barium is deposited on one of its faces is a direct measure of the quantity of barium condensed on the face itself.
  • On the ordinates of this diagram are reported the percentages of barium thick ness referred to the conventional getter at the end of evaporation, on the abscissae is reported the time of evaporation.
  • the external radio frequency power is applied at zero time (not shown).
  • the starter times S and 8 show the instant when the exothermic reaction begins, while the total times T and T are the times at which the radiofrequency current to the getter container is discontinued.
  • the curve 7 refers to the conventional getter, while curve 8 refers to the getter of the present invention.
  • a getter device for use in closed vessels comprising an evaporable getter metal; a gas releasing material which releases a gas at a temperature below the evaporation temperature of the getter metal and which is stable to temperatures up to 400 C. said gas being readsorbable by the getter metal.
  • a getter device comprising an evaporable getter metal and a gas releasing material, said getter device when mounted within a picture tube having a tube screen and tube walls and heated, evaporates the getter metal in the present of a gas released from the gas releasing material wherein said gas is present in an amount great enough to preferentially deposit the evaporated getter metal on the tube walls and wherein said gas is then sorbed by the getter metal [without deterimental effect on the sorptive capacity of the getter metal with respect to other residual gases present within the tube or evolved during operation to the tube].
  • a getter device especially adapted to produce within a picture tube a getter metal of particularly controlled distribution and of high sorptive capacity said getter device comprising:
  • a getter device for use within a picture tube having walls attached to a screen said device comprising an evaporable getter metal and Fe N means for releasing a gas in an amount sutficient to effect deposition of a major portion of the getter metal on the walls of the tube.
  • a getter device for use within a picture tube which has a substantially planar screen, a conically shaped wall section attached to the screen and a neck attached t0 said wall section, said getter device comprising:
  • a getter device for use within a picture tube which has a substantially planar screen, a conically shaped wall section attached to the screen and a neck attached to said wall section, said getter device being mountable in the vicinity of the point attachment of the neck of the tube and the wall section of the tube, and which tube has a given volume, said getter device comprising:
  • a gas containing material adapted to release its gas at a temperature below the temperature of evaporation of the getter metal, said gas containing material present in an amount such that the gas released is present in an amount such that the mean free path of the getter metal atoms within the tube during evaporation is equal to or less than the distance between the getter device and the tube screen.
  • the getter device of claim 8 wherein the gas produces within the tube a gas pressure of 5X10 to 1X 10* torr.
  • a getter device especially adapted to produce within a picture tube a getter metal of particularly controlled distribution and of high sorptive capacity said getter device comprising:

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US482104A 1965-02-25 1965-08-24 Gettering device including a getter metal and a gas releasing material Expired - Lifetime US3389288A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US664593A US3388955A (en) 1965-02-25 1967-08-10 Process for producing within electron tubes,in particular television picture tubes,a thin metallic film capable of sorbing their residual gases

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT170865 1965-02-25

Publications (1)

Publication Number Publication Date
US3389288A true US3389288A (en) 1968-06-18

Family

ID=11101980

Family Applications (1)

Application Number Title Priority Date Filing Date
US482104A Expired - Lifetime US3389288A (en) 1965-02-25 1965-08-24 Gettering device including a getter metal and a gas releasing material

Country Status (5)

Country Link
US (1) US3389288A (fr)
DE (1) DE1514552B2 (fr)
FR (1) FR1465051A (fr)
GB (1) GB1086489A (fr)
NL (1) NL132102C (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3605036A (en) * 1967-10-17 1971-09-14 Laser Sciences Inc Method and apparatus for thermochemically controlling the gas atmosphere of a gas coherent radiation generator
US3728004A (en) * 1971-06-25 1973-04-17 Gte Sylvania Inc Method of employing mercury-dispensing getters in fluorescent lamps
US3768884A (en) * 1970-05-04 1973-10-30 Getters Spa Gettering
DE2028949C3 (de) 1969-06-14 1979-12-06 S.A.E.S. Getters S.P.A., Mailand (Italien) Gettervorrichtung für Elektronenröhren
US4203860A (en) * 1970-09-10 1980-05-20 Tokyo Shibaura Electric Co., Ltd. Nitrogen-emitting composition to be used with flash getter materials
DE2066088C2 (de) * 1969-06-14 1982-05-13 S.A.E.S. Getters S.p.A., Milano Verfahren zur Ablagerung eines Gettermetalls
US4665343A (en) * 1984-07-05 1987-05-12 S.A.E.S. Getters S.P.A. Low methane getter device
US6583559B1 (en) 1999-06-24 2003-06-24 Saes Getter S.P.A. Getter device employing calcium evaporation
US6793461B2 (en) 2001-10-29 2004-09-21 Saes Getters S.P.A. Device and method for producing a calcium-rich getter thin film
US6851997B2 (en) 2001-11-14 2005-02-08 Saes Getters S.P.A. Process for depositing calcium getter thin films inside systems operating under vacuum
WO2005087971A1 (fr) * 2004-03-15 2005-09-22 Ifire Technology Corp. Procede de filtration de l'oxygene et de l'eau pendant le depot sous vide de films de sulfure
WO2022261564A3 (fr) * 2021-06-11 2023-01-19 Helion Energy, Inc. Pompe à diffusion à absorption hybride

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8002836A (nl) * 1980-05-16 1981-12-16 Philips Nv Werkwijze voor het vervaardigen van een kleurentelevisiebeeldbuis voorzien van een gasabsorberende laag; kleurentelevisiebeeldbuis aldus vervaardigd en getterinrichting geschikt voor een dergelijke werkwijze.
NL8101459A (nl) * 1981-03-24 1982-10-18 Philips Nv Werkwijze voor het vervaardigen van een beeldweergeefbuis voorzien van een gasabsorberende laag; beeldweergeefbuis aldus vervaardigd en getterinrichting geschikt voor een dergelijke werkwijze.
DE3315011A1 (de) * 1983-04-26 1984-10-31 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Elektronenroehre mit leuchtschirm
GB0319171D0 (en) 2003-08-15 2003-09-17 Boc Group Plc Purifier/getter for vacuum and uhp gas applications

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1894948A (en) * 1929-10-29 1933-01-24 Siemens Ag Manufacture of electron discharge devices
GB496856A (en) * 1937-03-09 1938-12-07 Philips Nv Improvements in the manufacture of highly exhausted discharge tubes
US2540647A (en) * 1945-05-04 1951-02-06 Hartford Nat Bank & Trust Co Method of manufacturing electronic tubes with active getters
US2615140A (en) * 1948-09-28 1952-10-21 Hartford Nat Bank & Trust Co Electric discharge tube containing an alkaline metal
US2899257A (en) * 1959-08-11 Getter for electron discharge device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2899257A (en) * 1959-08-11 Getter for electron discharge device
US1894948A (en) * 1929-10-29 1933-01-24 Siemens Ag Manufacture of electron discharge devices
GB496856A (en) * 1937-03-09 1938-12-07 Philips Nv Improvements in the manufacture of highly exhausted discharge tubes
US2540647A (en) * 1945-05-04 1951-02-06 Hartford Nat Bank & Trust Co Method of manufacturing electronic tubes with active getters
US2615140A (en) * 1948-09-28 1952-10-21 Hartford Nat Bank & Trust Co Electric discharge tube containing an alkaline metal

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3605036A (en) * 1967-10-17 1971-09-14 Laser Sciences Inc Method and apparatus for thermochemically controlling the gas atmosphere of a gas coherent radiation generator
DE2028949C3 (de) 1969-06-14 1979-12-06 S.A.E.S. Getters S.P.A., Mailand (Italien) Gettervorrichtung für Elektronenröhren
DE2066088C2 (de) * 1969-06-14 1982-05-13 S.A.E.S. Getters S.p.A., Milano Verfahren zur Ablagerung eines Gettermetalls
US3768884A (en) * 1970-05-04 1973-10-30 Getters Spa Gettering
US4203860A (en) * 1970-09-10 1980-05-20 Tokyo Shibaura Electric Co., Ltd. Nitrogen-emitting composition to be used with flash getter materials
US3728004A (en) * 1971-06-25 1973-04-17 Gte Sylvania Inc Method of employing mercury-dispensing getters in fluorescent lamps
US4665343A (en) * 1984-07-05 1987-05-12 S.A.E.S. Getters S.P.A. Low methane getter device
US6583559B1 (en) 1999-06-24 2003-06-24 Saes Getter S.P.A. Getter device employing calcium evaporation
US6793461B2 (en) 2001-10-29 2004-09-21 Saes Getters S.P.A. Device and method for producing a calcium-rich getter thin film
US20040195968A1 (en) * 2001-10-29 2004-10-07 Saes Getters S.P.A. Composition used in producing calcium-rich getter thin film
US20050163930A1 (en) * 2001-10-29 2005-07-28 Saes Getters S.P.A. Device and method for producing a calcium-rich getter thin film
US7083825B2 (en) * 2001-10-29 2006-08-01 Saes Getters S.P.A. Composition used in producing calcium-rich getter thin film
US6851997B2 (en) 2001-11-14 2005-02-08 Saes Getters S.P.A. Process for depositing calcium getter thin films inside systems operating under vacuum
WO2005087971A1 (fr) * 2004-03-15 2005-09-22 Ifire Technology Corp. Procede de filtration de l'oxygene et de l'eau pendant le depot sous vide de films de sulfure
US20050227005A1 (en) * 2004-03-15 2005-10-13 Cheong Dan D Method for gettering oxygen and water during vacuum deposition of sulfide films
US8057856B2 (en) 2004-03-15 2011-11-15 Ifire Ip Corporation Method for gettering oxygen and water during vacuum deposition of sulfide films
WO2022261564A3 (fr) * 2021-06-11 2023-01-19 Helion Energy, Inc. Pompe à diffusion à absorption hybride

Also Published As

Publication number Publication date
DE1514552B2 (de) 1971-01-21
DE1514552A1 (de) 1969-12-04
FR1465051A (fr) 1967-01-06
NL132102C (fr) 1900-01-01
GB1086489A (en) 1967-10-11

Similar Documents

Publication Publication Date Title
US3389288A (en) Gettering device including a getter metal and a gas releasing material
US3582702A (en) Thermionic electron-emissive electrode with a gas-binding material
US3669567A (en) Gettering
US4342662A (en) Getter device
US4019077A (en) Field emission electron gun
Giorgi Getters and gettering
US3549937A (en) Low pressure mercury vapour discharge lamp including an alloy type getter coating
US3768884A (en) Gettering
US3388955A (en) Process for producing within electron tubes,in particular television picture tubes,a thin metallic film capable of sorbing their residual gases
US2100746A (en) Gettering vacuum tube
US3552818A (en) Method for processing a cathode ray tube having improved life
US3544829A (en) Low pressure mercury vapour discharge lamp
US3432712A (en) Cathode ray tube having a perforated electrode for releasing a selected gas sorbed therein
US4481441A (en) Method of manufacturing a picture display tube having a gas-absorbing layer; picture display tube thus manufactured, and gettering device suitable for such a method
US4530669A (en) Method of making a borided dispenser cathode
Holland Theory and design of getter-ion pumps
US3356436A (en) Gettering system for electron tubes
JP2001357814A (ja) 極高真空スパッタイオンポンプ
RU2169960C2 (ru) Испаряемое газоулавливающее устройство с уменьшенным временем активации
US1752747A (en) Electron-discharge device and getter therefor
US1722121A (en) Electron-discharge device
US3684401A (en) Cathode-getter materials for sputter-ion pumps
JPS6349852B2 (fr)
JPS6348387B2 (fr)
US2686735A (en) Cathode material