US3920355A - Gettering - Google Patents
Gettering Download PDFInfo
- Publication number
- US3920355A US3920355A US447307A US44730774A US3920355A US 3920355 A US3920355 A US 3920355A US 447307 A US447307 A US 447307A US 44730774 A US44730774 A US 44730774A US 3920355 A US3920355 A US 3920355A
- Authority
- US
- United States
- Prior art keywords
- getter
- ring
- releasing material
- zone
- getter metal
- 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
Links
Images
Classifications
-
- 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
Definitions
- ABSTRACT A getter device for releasing an evaporable getter metal such as barium in a vacuum tube comprising a ring and a getter metal releasing material attached to the ring.
- the getter metal releasing material has a zone of high density adjacent to the ring. It also has a zone of low density adjacent to the Zone of high density. In getter devices of the present invention, upon release of the getter metal, the getter metal releasing material remains attached to the ring.
- Getter devices which release an evaporable getter metal in a vacuum tube are well known.
- These getter devices generally comprise a ring and a getter metal releasing material attached to the ring.
- the getter metal is released from the getter metal releasing material by subjecting the ring to radio frequency currents. These radio frequency currents induce heating in the ring and in the getter metal releasing material causing the getter metal releasing material to release its getter metal.
- radio frequency currents induce heating in the ring and in the getter metal releasing material causing the getter metal releasing material to release its getter metal.
- the getter metal releasing material Upon release of the getter metal, there is a tendency for the getter metal releasing material to become detached from the ring.
- Another object is to provide an improved getter de- I ing to the present invention, it has been found that the getter metal releasing material remains attached to the ring after release of its getter metal.
- Any evaporable getter metal can be employed in the devices of the present invention such as the alkali or alkaline earth metals, examples of which include among towards air and are easier to handle.
- the preferred getvice in which separation of the getter material from'the ring is minimized.
- a further object is to provide an improved getter device which has a reduced tendency to release loose particles.
- a still further object of the present invention is to provide an improved getter device accomplishing the above objects without adversely affecting other properties, such as the amount of getter metal released.
- Yet another object of the present invention is to provide an improved process for producing a getter device.
- FIG. 1 is a partially cut-away plan view of a getter device of the present invention
- FIG. 2 is a sectional view of the getter device of FIG.
- the getter metal releasing material has a zone of high density adjacent to the ring and a zone of lower density adjacent to the zone of high density.
- the getter device further comprises a third zone of high density.
- Accordter alloys are those of barium and aluminum, generally in weight ratio of about 10:5 to 10:20, and especially binary alloys containing about 50 to 56% barium, balance aluminum.
- the getter metals and getter alloys can be employed alone or in admixture with other substances. When employed alone so-called endothermic getter devices are produced. These devices rely upon induction heating in order to provide the heat of vaporization of the getter metal. More preferably the getter alloy is employed admixed with nickel to create an exothermic getter device wherein a portion of the heat of vaporization of the getter metal is supplied by an exothermic reaction between the nickel and the bariumaluminum alloy.
- The'getter metal-releasing materials of the present invention preferably contain a small amount of a gasreleasing material as described for example in US. Pat. Nos. 3,389,288 and 3,669,567.
- the particulate getter metal releasing material is em ployed in the present invention in the same particle sizes as employed in the prior art.
- the particulate material generally passes through a US. standard screen of 100 mesh per inch and preferably passes through a US. standard screen of 200 mesh per inch.
- a ring can have any of a variety of forms as long as it retains the getter metal releasing material at least prior to getter metal release.
- One preferred embodiment of a ring is an annular ring having a bottom wall attached to an inner wall which is substantially vertical and also attached to an outer wall which is also substantially vertical.
- the bottom wall can have a plurality of holes therein, in order to increase the exposed surface area to mass ratio.
- the exposed surface area to mass ratio of the getter metal releasing material is generally greater than 0.45 mm lmg and is preferably between 0.6 and 0.8 mm /mg.
- the ring is preferably constructed of a material which can be heated by radio frequency currents. Examplesof such an inductively-heatable material include among others iron, nickel and stainless steel.
- a getter device 10 of the present invention comprising an annular ring 11 and a getter metal releasing material l2attached to the ring 11.
- the ring 11 comprises a bottom wall 14 attached to an outer wall 15 and an inner wall 16.
- the bottom wall I 14 is provided with a plurality of holes 18, 19.
- the getpressed free-flowing state is placed in the ring 11.
- a plate 30 is placed underneath the ring 11 in order to keep the material 12 from flowing out of the ring 11 through the hole 18.
- the upper surface 32 of the uncompressed material 12 is substantially planar.
- a die 33 having a first flat annular surface 34 and a second flat annular surface 35 and having an annular depression 36 between the surfaces 34 and 35 is placed above the material 12.
- the die 33 is then moved downwardly causing the material 12 to be compressed unevenly.
- the zones of the material 12 underneath the flat surfaces 34 and 35 will becompressed to a greater degree than the zone of the material 12 underlying the depression 36.
- the greater degree of compression is caused by a reduction in the amount of free space in the material which gives zones of different bulk densities in the compressed material 12.
- the compression in all zones is sufficient to cause the particles of the material 12 to adhere to one another.
- the getter device produced by the above described process has an annular zone 40 of high density adjacent to the outer wall 15.
- the device 10 also has an annular zone 41 of high density adjacent to the inner wall 16. Between these zones 40 and 41 is an intermediate zone 42 which has a density less than that of zones 40 and 41.
- the upper surface 43 of the getter metal releasing material 12 has an elevated annular ridge 44 which is substantially concentric with the annular ring 11.
- the ridge 44 has a radius of curvature, R, which is greater than the depth of the getter metal releasing material 12.
- a getter device 10 as shown in FIGS. 1 and 2 having a ridge 44 is produced by pressing into an annular ring 11, 460mg of an alloy containing 56 weight percent barium, balance aluminum; 516mg nickel; and 24mg Fe N, in the manner described herein with reference to FIGS. 4 and 5.
- a number of such getter devices 10 are each placed in a vacuum tube and heated by a radio frequency induction coil until the barium is evaporated. Identical tests are conducted with prior art getter devices identical to the getter device 10 but having no ridge 44. Fewer of the getter devices of the present invention exhibit undesirable separation of the getter metal releasing material 12 from the ring 11 than do the prior art getter devices.
- a getter device for releasing an evaporable getter metal in a vacuum tube comprising:
- the getter metal releasing material remains attached to the ring.
- the getter device of claim 1 wherein the ring is an annular ring having a bottom wall attached to an inner and an outer wall, wherein the getter metal releasing material is in particulate form, the particles of which are compressed to different densities within the annular ring, wherein said different densities are achieved by reducing the amount of free space in the getter metal releasing material, said getter metal releasing material having a first annular zone of high density adjacent to the outer wall of the annular ring and a second annular zone of high density adjacent to the inner wall of the annular ring and an intermediate annular zone of density lower than the density in either the first or the second zone, said intermediate zone lying between the first and second zones being contiguous thereto.
- the getter device of claim 2 wherein the upper surface of the getter material is non-planar and comprises an elevated annular ridge spaced from both the inner and the outer walls of the ring.
- the getter device of claim 1 wherein the surface of the getter metal releasing material has a first planar portion adjacent to the outer wall of the ring and substantially perpendicular thereto and a second planar portion adjacent to the inner wall of the annular ring and substantially perpendicular, thereto said first and second surfaces being contiguous with a third surface which is curved above the first and second surfaces.
- the getter device of claim 1 wherein the particulate getter metal releasing material in its uncompressed state has a particle size such that it passes through a US. standard screen of mesh per inch.
- the getter device of claim 1 wherein the particulate getter metal releasing material in its uncompressed state has a particle size such that it passes through a US. standard screen of 200 mesh per inch.
- getter metal releasing material is a mixture of an alloy of barium with aluminum in particulate form mixed with particulate nickel.
- the getter device of claim 1 further comprising a ceramic heat insulating base attached to the ring and extending substantially completely underneath the ring.
- the getter device of claim 1 wherein the ring is constructed of an inductively heatable material.
- a getter device for releasing a evaporable getter metal in a vacuum tube comprising:
- said getter metal releasing material having a second annular zone wherein the particles are highly compressed said second annular zone being adjacent to the inside wall
- a getter device for releasing an evaporable getter metal in a vacuum tube comprising:
- a process for producing a getter device comprising an annular ring and a getter metal releasing material within the annular ring wherein said getter metal releasing material has a reduced tendency to separate from the annular ring during heating by radio frequency currents, said process comprising the steps of:
Landscapes
- Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
- Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT86217/74A IT1016466B (it) | 1974-02-28 | 1974-02-28 | Dispositivo getter perfezionato del tipo a materiale getterante evaporabile |
Publications (1)
Publication Number | Publication Date |
---|---|
US3920355A true US3920355A (en) | 1975-11-18 |
Family
ID=11330237
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US447307A Expired - Lifetime US3920355A (en) | 1974-02-28 | 1974-03-01 | Gettering |
Country Status (2)
Country | Link |
---|---|
US (1) | US3920355A (it) |
IT (1) | IT1016466B (it) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3996488A (en) * | 1974-07-19 | 1976-12-07 | Saes Getters S.P.A. | Getter device with deflector |
US4961040A (en) * | 1988-04-20 | 1990-10-02 | Saes Getters Spa | High yield pan-shaped getter device |
US5610438A (en) * | 1995-03-08 | 1997-03-11 | Texas Instruments Incorporated | Micro-mechanical device with non-evaporable getter |
US20070035233A1 (en) * | 2002-12-19 | 2007-02-15 | Shigemi Hirasawa | Display device |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3211280A (en) * | 1962-06-21 | 1965-10-12 | Union Carbide Corp | Getter assembly |
US3547255A (en) * | 1969-03-24 | 1970-12-15 | Gen Electric | Getter assembly |
US3560788A (en) * | 1968-12-11 | 1971-02-02 | Union Carbide Corp | R-f energizable, pan-shaped getter for television tube |
US3669567A (en) * | 1969-06-14 | 1972-06-13 | Getters Spa | Gettering |
US3820919A (en) * | 1970-12-21 | 1974-06-28 | Siemens Ag | Zirconium carbon getter member |
-
1974
- 1974-02-28 IT IT86217/74A patent/IT1016466B/it active
- 1974-03-01 US US447307A patent/US3920355A/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3211280A (en) * | 1962-06-21 | 1965-10-12 | Union Carbide Corp | Getter assembly |
US3560788A (en) * | 1968-12-11 | 1971-02-02 | Union Carbide Corp | R-f energizable, pan-shaped getter for television tube |
US3547255A (en) * | 1969-03-24 | 1970-12-15 | Gen Electric | Getter assembly |
US3669567A (en) * | 1969-06-14 | 1972-06-13 | Getters Spa | Gettering |
US3820919A (en) * | 1970-12-21 | 1974-06-28 | Siemens Ag | Zirconium carbon getter member |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3996488A (en) * | 1974-07-19 | 1976-12-07 | Saes Getters S.P.A. | Getter device with deflector |
US4961040A (en) * | 1988-04-20 | 1990-10-02 | Saes Getters Spa | High yield pan-shaped getter device |
US5610438A (en) * | 1995-03-08 | 1997-03-11 | Texas Instruments Incorporated | Micro-mechanical device with non-evaporable getter |
US20070035233A1 (en) * | 2002-12-19 | 2007-02-15 | Shigemi Hirasawa | Display device |
US7348721B2 (en) * | 2002-12-19 | 2008-03-25 | Hitachi Displays, Ltd. | Display device |
Also Published As
Publication number | Publication date |
---|---|
IT1016466B (it) | 1977-05-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3920355A (en) | Gettering | |
US3669567A (en) | Gettering | |
US3624007A (en) | Electrical contact material and method of making and utilizing the same | |
JPS60227343A (ja) | ゲッタ・アセンブリの成形方法 | |
US3385420A (en) | Getter devices | |
US3768884A (en) | Gettering | |
US2553016A (en) | Foamlike metal | |
US3148056A (en) | Cathode | |
US20040104675A1 (en) | Evaporable getter device for cathode-ray tubes | |
US2018965A (en) | Clean-up agent | |
US4530669A (en) | Method of making a borided dispenser cathode | |
US4128782A (en) | Getter holder and electric discharge tube comprising such a holder | |
EP0853328B1 (en) | Frittable evaporable getter device having a high yield of barium | |
US1963829A (en) | Producing high vacua | |
GB947999A (en) | Improvements in or relating to oxide cathodes | |
US4407657A (en) | Gettering device and method | |
US4147954A (en) | Thermionic electron emitter | |
US3211280A (en) | Getter assembly | |
US2535713A (en) | Protective plating for electrodes | |
JPS63192206A (ja) | Sm−Co系磁石の焼結方法 | |
US2175707A (en) | Spacer for electron discharge devices | |
JPH0378928A (ja) | 大型電子管用ゲッタ装置 | |
US1917044A (en) | Process for manufacturing highly emissive cathodes | |
JPS6233298B2 (it) | ||
US2167128A (en) | Method of producing superficial carbonization of metals and alloys |