EP0273884A2 - Dispositif et composition permettant de libérer de l'azote pendant la fabrication d'un tube à rayons cathodiques - Google Patents

Dispositif et composition permettant de libérer de l'azote pendant la fabrication d'un tube à rayons cathodiques Download PDF

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Publication number
EP0273884A2
EP0273884A2 EP87830454A EP87830454A EP0273884A2 EP 0273884 A2 EP0273884 A2 EP 0273884A2 EP 87830454 A EP87830454 A EP 87830454A EP 87830454 A EP87830454 A EP 87830454A EP 0273884 A2 EP0273884 A2 EP 0273884A2
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EP
European Patent Office
Prior art keywords
percent
weight smaller
weight
smaller
particulate
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EP87830454A
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German (de)
English (en)
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EP0273884A3 (en
EP0273884B1 (fr
Inventor
Daniele Martelli
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SAES Getters SpA
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SAES Getters SpA
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Publication of EP0273884A3 publication Critical patent/EP0273884A3/en
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    • 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
    • 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
    • H01J7/183—Composition or manufacture of getters
    • 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 device and compo­sition of matter for the release of nitrogen during the manufacture of a cathode ray tube.
  • a first disadvantage is that the nitrogen is released at an undesirable period of time relative to the evaporation of the barium.
  • Another disadvantage is that the nitrogen is released exceedingly quickly and a nitrogen pressure is created within the CRT outside the range of pressures desired to effectively control the distribution and subsequent sorption capabilities of the barium film.
  • Yet another disadvantage is the fact that the extremely rapid production of nitrogen creates a miniature explo­sion of the nitrogen releasing material thus producing large quantities of loose particles. These loose parti­cles may enter the gun region of the cathode ray tube causing short circuits of the electrodes or the parti­cles may find their way to the shadow mask and block passage of the image producing electron beams thus degrading picture quality.
  • particulate Fe4N can have any particle size distribution which is capable of withstanding the frit process when in admixture with nickel powder and aluminium powder.
  • the parti­culate Fe4N has a particle size distribution of: 10-50 percent by weight smaller than 5 ⁇ m 60-90 percent by weight smaller than 10 ⁇ m 83-98 percent by weight smaller than 15 ⁇ m 92-100 percent by weight smaller than 20 ⁇ m 97-100 percent by weight smaller than 30 ⁇ m
  • the particulate Ni may have any particle size distribution which is capable of withstanding a frit seal process and preferably has a particle size distribution of: 0- 9 percent by weight smaller than 5 ⁇ m 7-28 percent by weight smaller than 10 ⁇ m 21-46 percent by weight smaller than 15 ⁇ m 35-56 percent by weight smaller than 20 ⁇ m 49-65 percent by weight smaller than 30 ⁇ m 58-75 percent by weight smaller than 40 ⁇ m 69-86 percent by weight smaller than 60 ⁇ m 78-93 percent by weight smaller than 80 ⁇ m at least 92 percent by weight smaller than 100 ⁇ m
  • the particulate Al may have any particle size distribution which is capable of withstanding a frit seal process and preferably has a particle size distribution of: 4.5- 9 percent by weight smaller than 40 ⁇ m 7-16 percent by weight smaller than 60 ⁇ m 15-25 percent by weight smaller than 80 ⁇ m 20-45 percent by weight smaller than 100 ⁇ m 30-60 percent by weight smaller than 150 ⁇ m at least 95 percent by weight smaller than 250 ⁇ m
  • the weight percentage of the components Fe4N, Ni and Al can vary over a wide range. It is preferable that the particulate Fe4N is present at a percentage of from 40 to 80%. At percentage compositions less than 40% there is insufficient Fe4N to create a suitable pressure within CRT whereas if the percentage is greater than 80% there is an insufficient Ni and Al to cause a sufficiently exothermic reaction to aid the release of N2.
  • the Ni should be present in a weight percentage of from 20 to 40%. At a percentage weight less than 20% there is insufficient Ni for the exothermic react­ion to aid release of N2 whereas if the percentage Ni is higher than 40% there is a risk of too much heat being produced with an excessive speed in the release of N2.
  • the Al should be present in a weight percen­tage of from 5 to 20%. If the percentage weight of Al is less than 5% there is insufficient Al present to produce sufficient heat in the exothermic reaction to cause release of N2 from the Fe4N, whereas if more than 20% of Al is present then the exothermic reaction may take place too violently causing excessive speed in the release of N2.
  • the nitrogen releasing composition comprises 60% Fe4N, 30% Ni and 10% Al.
  • the ratio of Ni to Al can vary widely but general­ ly is chosen to produce the maximum amount of heat when the Ni is combined with the Al.
  • the maximum amount of heat is generally produced within weight ratios of Ni to Al of 1 : 10 to 10 : 1.
  • An ideal ratio of Ni to Al is about 3: 1.
  • the ratio of Fe4N to the combined weight of Ni and Al is chosen to release substantially all the nitrogen from the Fe4N within a very short period of time generally less than five and preferably less than three seconds.
  • the Fe4N is generally present in the composition within a weight ratio of 1 : 5 to 5 : 1 and preferably 1 : 2 to 2 :1 compared to the combin­ed weight of Ni and Al.
  • the composition is preferably adopted as a second source of nitrogen in a N2 doped getter, and is preferably contained within a holder such as a capsule.
  • the capsule may be of any suitable material for holding the mixture for instance ceramic. Preferably it is of metal. Even more preferably it is of nichrome or stainless steel. Any suitably shaped holder may be used but it is preferably in the form of a hollow cylinder closed at one end.
  • N2 releasing capsule for use in a so called “delayed nitrogen doped getter" will now be described with reference to Fig. 1 and Fig. 2 wherein 102 is a nitrogen gas releasing capsule comprising a holder 104 in the form of a cylinder 106 integrally closed at one end by means 108.
  • the open end 110 is horizontally flared in the form of a flange 112.
  • Flange 112 has present a series of pips for subsequent projection welding for support purposes 114, 114 ⁇ , 114 ⁇ .
  • Fig. 2 illustrates the use of a nitrogen gas releasing capsule as a delayed nitrogen doped gas source or second gas source in a nitrogen doped getter.
  • the evaporable getter device 202 comprises a ring shaped holder 204 supporting an evaporable getter metal vapour releasing material 206.
  • Evaporable getter material generally comprises a barium aluminium alloy of composition approximately BaAl4 in admixture with approximately an equal weight of Ni powder.
  • Fe4N as a first source of N2.
  • This mixture is any mixture known in the art, see for example USA Patent No. 4.077.899 which is capable of withstanding the frit process.
  • the evaporable getter device 202 further comprises a reflecting shield 208 which serves to hold a ceramic disk 210 to prevent a heated getter device from cracking the nearby glass wall of a cathode ray tube.
  • a nitrogen gas releasing capsule 212 identical in all respects to capsule 102 shown in Fig. 1 is projection welded to the centre portion of reflecting shield 208.
  • composition of matter for the release of nitrogen gas is meant to include both the composition prior to and after nitrogen gas release. This term embraces both the material in the solid form sold with the getter device and in the form in which it is found in an operating tube wherein the major part of the nitrogen has been evaporated from the composition and is chemically combined with the getter film on the inside surfaces of the tube.
  • getter metal vapor releasing material as used in the specification and claims herein is meant to include both the material prior to and after getter metal vapor release. This term embraces both the material in the form sold with the getter device and in the form in which it is found in an operating tube wherein the bulk of the getter metal has been evaporated from the material and is in the form of a film on the inside surfaces of the tube.
  • compositions of the present invention have the property od not releasing particles even after being heated in air at temperatures of 100 to 450°C for a period of two hours.
  • a powder mixture is prepared comprising 60% by weight of Fe4N having a preferred particle size distribution as described above.
  • the mixture further comprises 30% of powdered titanium having a particle size distribution of 2-20 percent by weight smaller than 10 ⁇ m 15-40,2 percent by weight smaller than 20 ⁇ m 30-70 percent by weight smaller than 30 ⁇ m 50-90 percent by weight smaller than 40 ⁇ m 80-92 percent by weight smaller than 50 ⁇ m at least 90% percent by weight smaller than 60 ⁇ m and 10% of particulate Al having a particle size distri­bution as described above.
  • Example 2 This example was carried out under the same conditions as Example 1 with the sole exception that in the composition for release of nitrogen gas the titanium was substituted with nickel having the particle size distribution described in US Patent No. 4.077.899 where its use is disclosed to avoid excessive exother­mic reactions.
  • This distribution was as follow: 0% by weight smaller than 15 ⁇ m 0.1-0.2% by weight smaller than 20 ⁇ m 3-10% by weight smaller than 30 ⁇ m 22-60% by weight smaller than 40 ⁇ m 70-96% by weight smaller than 50 ⁇ m 86-99% by weight smaller than 55 ⁇ m 97-100% by weight smaller than 65 ⁇ m
  • This Example is designed to show the behaviour of a composition of matter for the release of nitrogen gas of the present invention held in a capsule after having been subjected to a frit sealing process.
  • a powder mixture is prepared having exactly the same weight composition and particle size ranges except that the Ni is replaced by Ni having a particle size distribution according to the preferred Ni distri­bution as described above.
  • Getter capsules are exposed to air at exactly the same temperature and for exactly the same time as in Example 1. When the capsules are caused to release N2 in an evacuated system the N2 is found to be released in a controlled manner without the expulsion of any loose particles from the capsules.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
  • Battery Electrode And Active Subsutance (AREA)
EP87830454A 1986-12-22 1987-12-21 Dispositif et composition permettant de libérer de l'azote pendant la fabrication d'un tube à rayons cathodiques Expired - Lifetime EP0273884B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT2280886 1986-12-22
IT22808/86A IT1198229B (it) 1986-12-22 1986-12-22 Dispositivo e composizione per l'emissione di gas azoto durante la preparazione di un tubo a raggi catodici

Publications (3)

Publication Number Publication Date
EP0273884A2 true EP0273884A2 (fr) 1988-07-06
EP0273884A3 EP0273884A3 (en) 1989-01-25
EP0273884B1 EP0273884B1 (fr) 1991-10-16

Family

ID=11200667

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87830454A Expired - Lifetime EP0273884B1 (fr) 1986-12-22 1987-12-21 Dispositif et composition permettant de libérer de l'azote pendant la fabrication d'un tube à rayons cathodiques

Country Status (5)

Country Link
EP (1) EP0273884B1 (fr)
JP (1) JPH0722005B2 (fr)
KR (1) KR950001489B1 (fr)
DE (1) DE3773877D1 (fr)
IT (1) IT1198229B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2471740A (en) * 2009-07-10 2011-01-12 Beijing Synergy Vacuum Glazing Technology Co Ltd An encapsulated getter

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3768884A (en) * 1970-05-04 1973-10-30 Getters Spa Gettering
GB2076586A (en) * 1980-05-16 1981-12-02 Philips Nv Gas-releasing getter device for television display tubes

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3768884A (en) * 1970-05-04 1973-10-30 Getters Spa Gettering
GB2076586A (en) * 1980-05-16 1981-12-02 Philips Nv Gas-releasing getter device for television display tubes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2471740A (en) * 2009-07-10 2011-01-12 Beijing Synergy Vacuum Glazing Technology Co Ltd An encapsulated getter
GB2471740B (en) * 2009-07-10 2011-08-17 Beijing Synergy Vacuum Glazing Technology Co Ltd An encapsulated getter arranged vacuum glazing

Also Published As

Publication number Publication date
JPH01173551A (ja) 1989-07-10
EP0273884A3 (en) 1989-01-25
EP0273884B1 (fr) 1991-10-16
IT1198229B (it) 1988-12-21
DE3773877D1 (de) 1991-11-21
JPH0722005B2 (ja) 1995-03-08
KR950001489B1 (ko) 1995-02-25
KR880008375A (ko) 1988-08-31
IT8622808A0 (it) 1986-12-22

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