EP0641007A2 - Structure de cathode à réserve du type à chauffage direct - Google Patents

Structure de cathode à réserve du type à chauffage direct Download PDF

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Publication number
EP0641007A2
EP0641007A2 EP94300660A EP94300660A EP0641007A2 EP 0641007 A2 EP0641007 A2 EP 0641007A2 EP 94300660 A EP94300660 A EP 94300660A EP 94300660 A EP94300660 A EP 94300660A EP 0641007 A2 EP0641007 A2 EP 0641007A2
Authority
EP
European Patent Office
Prior art keywords
pellet
heating
filaments
direct
cathode structure
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.)
Ceased
Application number
EP94300660A
Other languages
German (de)
English (en)
Other versions
EP0641007A3 (fr
Inventor
Chang-Seob Kim
Seok-Bong Shon
Seok-Gi Kim
Dong-Gil Jang
Bong-Uk Jeong
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.)
Samsung SDI Co Ltd
Original Assignee
Samsung Display Devices Co Ltd
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 Samsung Display Devices Co Ltd filed Critical Samsung Display Devices Co Ltd
Publication of EP0641007A2 publication Critical patent/EP0641007A2/fr
Publication of EP0641007A3 publication Critical patent/EP0641007A3/fr
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/15—Cathodes heated directly by an electric current
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/13—Solid thermionic cathodes
    • H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
    • H01J1/28—Dispenser-type cathodes, e.g. L-cathode

Definitions

  • the present invention relates to a direct-heating-type dispenser cathode structure, and more particularly, to a direct-heating-type dispenser cathode structure of an electron gun for use in a color cathode ray tube where rapid thermion emission is possible.
  • a cathode emits thermions by thermal energy and is largely divided into two types.
  • One is an indirect-heating type in which indirect heating is used, which has a separated filament and thermion emission source.
  • Another is a direct-heating type in which direct heating is used, which has a connected filament and thermion emission source.
  • an indirect-heating-type cathode is applied to an electron gun which needs a large amount of thermions.
  • examples of such include an oxide cathode and a dispenser cathode.
  • the indirect-heating-type cathode comprises a sleeve in which a filament is provided, and a base metal or a cathode material reservoir fixed onto the sleeve.
  • the base metal is mainly applied to an oxide cathode while the reservoir is applied to a dispenser cathode.
  • a direct-heating-type cathode is applied to an electron gun for use in a small cathode ray tube, like the viewfinder of a video camera, and generally comprises a base metal or a medium for carrying cathode material which is to be directly fixed to the filament.
  • cathode material is deposited on the surface of the base metal, and the cathode material carrying media can be applied to large or industrial cathode ray tubes which require a large amount of current.
  • a porous pellet impregnated with a dispenser-type cathode material is an example of the carrying medium.
  • a U.S. patent application (filed September 14, 1993) based on Korea Patent Application No. 91-9461 (by the present Applicant) discloses a structure in which a porous pellet is directly fixed onto a filament and is as shown in FIG.1 of the accompanying drawings.
  • filament 2 is directly secured to both sides of a porous pellet 1 which contains cathode material.
  • Filament 2 is directly secured to the side of pellet 1 as shown in FIG. 2 of the accompanying drawings, and filament 2' is buried in the body of porous pellet 1 as shown in FIG. 3 of the accompanying drawings.
  • the porous pellet of the conventional direct-heating-type dispenser cathode structure is directly heated by the filament which is directly secured to the body of a pellet, and directly emits heat by the filament current. Therefore, it takes a very short time to start thermion emission after current is applied, and particularly, high-density thermion emission can be obtained.
  • a direct-heating-type cathode structure comprising a porous pellet which includes cathode material, and at least three filaments extending from the outer surfaces of the porous pellet.
  • the direct-heating-type cathode structure further comprises a supporter which supports the filaments, and an insulating block for supporting the supporter.
  • An embodiment of the direct-heating-type cathode structure of the present invention for use in an electron tube comprises a porous pellet is manufactured from either one selected from the group consisting of tungsten and molybdenum powders, and the cathode material includes an alkaline earth metal oxide of barium.
  • the porous pellet can be formed so as to have a circular cross-section or polygonal cross-section.
  • the filaments are disposed to be directly secured to the pellet body and spaced by a predetermined angle from one another.
  • the filaments form a supporting structure having three or more contact points with respect to the pellet.
  • the filament can also be formed of a material which penetrates the pellet body. However, several filaments which are exposed to the exterior of the pellet body can be obtained from a single material.
  • the material of the pellet includes a binder, for example Al2O3, for combining the metal powders.
  • the cathode material preferably includes at least one metal oxide powder selected from the group consisting of europium (Eu) oxide, scandium (Sc) oxide, indium (In) oxide and iridium (Ir) oxide. It is characteristically advantageous also to include SrCO3 in the amount of 2 ⁇ 29wt %.
  • a pellet obtained by compression molding and sintering the mixture of the cathode material and other materials therefor gives an advantage in manufacturing. It is more desirable to form a coating layer on the pellet surface, by at least one element selected from the group consisting of iridium (Ir), indium (In), osmium (Os), ruthenium (Ru) and rhenium (Re), so as to suppress the evaporation of barium (Ba) oxide and the resulting decrease in work function.
  • Ir iridium
  • In indium
  • Os osmium
  • Ru ruthenium
  • Re rhenium
  • the filaments are installed inside the pellet so as to cross each other. It is desirable to install the filaments so as to contact each other in the pellet, and it is most desirable that the filaments are integrally formed.
  • a porous pellet 100 i.e., a source of electron emission, consists of a porous material obtained by compression-molding and sintering the powder of refractory metals such as molybdenum or tungsten.
  • the porous portion of pellet 100 is filled with cathode material.
  • Porous pellet 100 is a hexahedron obtained by compression-molding and sintering a mixture of tungsten and/or molybdenum powder, an alkaline earth metal oxide including barium, Al2O3 powder and at least one metal oxide powder selected from Eu oxide, Sc oxide, In oxide or Ir oxide.
  • each end portion of four filaments 200 is secured to each side of pellet 100 while the other ends extend downward, thereby to form a structure for supporting the raised pellet 100.
  • Pellet 100 can be regarded as having four feet-like components when the four filaments are viewed as one filament. However, these four filaments 200 are installed so as to cross one another, passing through the body of pellet 100. Therefore, in practice, the four filaments exposed to the outside of the pellet are obtained by two filaments passing through pellet 100. The two filaments 200 make contact with each other when they cross inside pellet 100, but the two filaments may cross without contacting each other.
  • a coating layer 400 is formed on the upper surface of pellet 100 so as to prevent a decrease in work function and the evaporation of the cathode material, as shown in FIG.6.
  • Coating layer 400 is formed of at least one element selected from the group consisting of Ir, In, Os, Ru and Re.
  • FIGs.7 and 8 show two examples of the connecting structure of filament 200 with respect to pellet 100.
  • filaments 200 are respectively welded to the sides of pellet 100.
  • opposing filaments 200 are coupled to form a single body, and hence two filaments crossing each other are installed so as to pass through the body of pellet 100.
  • the four filaments 200 exposed on the outside of pellet 100 can be obtained from two filaments passing through pellet 100.
  • two filaments cross in contact with or separated from each other inside pellet 100.
  • FIG. 9 shows another embodiment in which filaments 200 pass through pellet 100.
  • the four filaments 200 extending down the sides of pellet 100 are combined into one.
  • filament 200 forms a cross-shaped single unit.
  • the cathode structure described above has four filaments, but the formation of a single pellet having three filaments is possible with a slight modification. However, it is preferable to prepare four filaments for a single pellet, considering various points.
  • the filaments act as supports for supporting both the pellet and heater, and accordingly, the pellet can be kept stable since at least three filaments support the pellet to maintain balance, even though filament strength is weakened by the applied current which heats the filament. Thus, pellet 100 is not greatly affected by external impacts, thereby to reduce an unstableness of the screen and lessen the occurrence of color variations in the CRT.
  • each filament is directly welded to the side of a pellet
  • the pellet heats simultaneously with the filament since the current passes directly through the pellet as well as the filament.
  • Such a filament configuration has the effect of faster heating than that in which the filament passes through the pellet, which also emits thermions relatively fast.
  • Pellet 100 can be modified into various shapes.
  • pellet 100 can be formed so as to have a circular cross-section, as shown in FIG.10, or a polygonal cross-section as shown in FIGs.11 and 12.
  • filaments 200 are secured to every other side surface, to provide four filaments. If necessary, the filament can be installed onto each surface, which results in a total of eight filaments.
  • FIG. 12 shows pellet 100 having six side surfaces. Here, the pellet has three filaments 200. However, a filament can be attached to each surface, so as to form a single pellet 100 having six filaments as shown in FIG. 13.
  • FIGs. 14 and 15 show an embodiment of the direct-heating-type cathode structure of the present invention which can be used for a monochromatic cathode ray tube.
  • filaments 200 are provided on each of four side surfaces of the hexahedron pellet 100.
  • Filaments 200 are fixed by welding to two supporters 400 installed directly onto a fixed block 300.
  • two welding surfaces 401 and 402 are provided for each support 400, and a respective single filament 200 is fixed to each welding surface 401 and 402.
  • this structure two filaments are connected in common. Therefore, the current flows in via two filaments and flows out via the remaining two filaments.
  • This kind of current application structure can be applied to the above-described filament structure of the present invention. In this structure, since heat is simultaneously provided to the pellet from four filaments, the pellet can quickly reach the temperature at which thermion emission is possible.
  • the pellet When the filament is welded to the pellet, the pellet is self-heated since the pellet is located in the current path. At this time, a plurality of filaments are divided into two groups through which voltage is applied to the pellet, since the two filaments are connected in common. That is, the current flows into a single pellet through the filament of group 1, and the current flows out from a single pellet through the filament of group 2. Accordingly, the combined resistance of the filament decreases, which results in an increase in the distribution voltage for the pellet. Thus, since the heating of the filament decreases due to the increase in distribution voltage while the heating of the pellet increases, the pellet reaches the thermion emission point faster, thereby to enable thermion emission immediately after current is applied.
  • a voltage is applied via the two groups, in the voltage application structure. That is, current flows into a single pellet via the filament of group 1, and the current flows out via the remaining filament of group 2.
  • a pellet has two current application terminals, and since each terminal consists of a plurality of filaments, the line resistance of each terminal is lowered.
  • lower line resistances are more advantageous in the prompt heating of the pellet, conversely to the conventional direct-heating-type cathode.
  • This decrease in resistance causes an increase in the distribution voltage ratio with respect to a pellet. Therefore, the amount of heat radiating outside the pellet decreases while the internal heating of the pellet is increased.
  • a temperature of 950 ⁇ 980°C is sufficient to obtain a current density of 10A/cm2. These temperature characteristics are equal to that of the existing indirect-heating impregnation-type cathode.
  • a cathode structure of the type shown in FIG.14 three cathode structures can be provided for a single electron gun, thereby to constitute an electron gun for use in a color cathode ray tube. Since the above cathode structure has an independent support block, means for fixing the supporting block for each cathode structure is required for the electron gun, when the above cathode structure is applied to an electron gun for use in a color cathode ray tube.
  • FIG.16 shows another embodiment of a cathode structure of the present invention which can be used for a color cathode ray tube.
  • the three cathode structures respectively having pellet 100 and filament 200 are positioned on a single insulating block 300.
  • three pairs of supporters 400 for fixing the filaments of each pellet are provided on the insulating block 300.
  • the structure for supporting the pellet having three or more filaments according to the present invention is very suitable for supporting pellets having considerable weight. That is, the pellet resists shock since it is supported by at least three filaments, thereby decreasing the potential deforming thereof. Additionally, the relative location for a first grid in an electron gun changes much less due to this shock-suppression effect.
  • the cathode structure and the reduced change of the first grid location together prevent the unstableness of the screen and the abnormal color generation due to minor impacts, thereby maintaining a stable screen quality. Particularly, the abnormal and permanent deformation according to extended operation is effectively suppressed.
  • a cathode structure of the present invention is more appropriate for use in a color cathode ray tube, and specifically in wide-screen televisions or industrial CRTs, rather than the general subminiature black-and-white cathode ray tube.

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  • Electrodes For Cathode-Ray Tubes (AREA)
  • Solid Thermionic Cathode (AREA)
EP94300660A 1993-08-31 1994-01-28 Structure de cathode à réserve du type à chauffage direct. Ceased EP0641007A3 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR9317567 1993-08-31
KR930017567 1993-08-31
KR930017566 1993-08-31
KR9317566 1993-08-31

Publications (2)

Publication Number Publication Date
EP0641007A2 true EP0641007A2 (fr) 1995-03-01
EP0641007A3 EP0641007A3 (fr) 1995-06-21

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ID=26629864

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EP94300660A Ceased EP0641007A3 (fr) 1993-08-31 1994-01-28 Structure de cathode à réserve du type à chauffage direct.

Country Status (3)

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EP (1) EP0641007A3 (fr)
JP (1) JPH0785775A (fr)
CN (1) CN1099903A (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0757370A1 (fr) * 1995-07-31 1997-02-05 Philips Patentverwaltung GmbH Tube à décharge électrique ou lampe à décharge et cathode à réserve comprenant du scandate
WO2000028566A1 (fr) * 1998-11-09 2000-05-18 Samsung Sdi Co., Ltd. Unite de cathode a chauffage direct et canon a electrons l'utilisant
EP1705684A1 (fr) * 2005-03-22 2006-09-27 ICT Integrated Circuit Testing Gesellschaft für Halbleiterprüftechnik mbH Emetteur stabilisé et méthode pour le stabiliser
US7189410B1 (en) 1990-11-27 2007-03-13 The American National Red Cross Supplemented and unsupplemented tissue sealants, methods of their production and use
US8480757B2 (en) 2005-08-26 2013-07-09 Zimmer, Inc. Implants and methods for repair, replacement and treatment of disease
US8497121B2 (en) 2006-12-20 2013-07-30 Zimmer Orthobiologics, Inc. Method of obtaining viable small tissue particles and use for tissue repair
US8518433B2 (en) 2003-12-11 2013-08-27 Zimmer, Inc. Method of treating an osteochondral defect
US9138318B2 (en) 2007-04-12 2015-09-22 Zimmer, Inc. Apparatus for forming an implant
US10167447B2 (en) 2012-12-21 2019-01-01 Zimmer, Inc. Supports and methods for promoting integration of cartilage tissue explants

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4789122B2 (ja) * 2006-09-05 2011-10-12 電気化学工業株式会社 電子源

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3273003A (en) * 1962-02-17 1966-09-13 Heraeus Gmbh W C Supporting members for a hot cathode block
US3384511A (en) * 1963-09-19 1968-05-21 Bell Telephone Labor Inc Cathode structures utilizing metal coated powders
US3689794A (en) * 1970-03-07 1972-09-05 Philips Corp Punctiform cathode, in particular suitable for detachable electric discharge tubes
US3758808A (en) * 1970-07-30 1973-09-11 Licentia Gmbh Dispenser cathode and method for making same
US3783330A (en) * 1971-04-02 1974-01-01 Mitsubishi Electric Corp Direct heated cathode
US4007393A (en) * 1975-02-21 1977-02-08 U.S. Philips Corporation Barium-aluminum-scandate dispenser cathode
EP0333369A1 (fr) * 1988-03-18 1989-09-20 Varian Associates, Inc. Cathode matricielle en solution solide

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3273003A (en) * 1962-02-17 1966-09-13 Heraeus Gmbh W C Supporting members for a hot cathode block
US3384511A (en) * 1963-09-19 1968-05-21 Bell Telephone Labor Inc Cathode structures utilizing metal coated powders
US3689794A (en) * 1970-03-07 1972-09-05 Philips Corp Punctiform cathode, in particular suitable for detachable electric discharge tubes
US3758808A (en) * 1970-07-30 1973-09-11 Licentia Gmbh Dispenser cathode and method for making same
US3783330A (en) * 1971-04-02 1974-01-01 Mitsubishi Electric Corp Direct heated cathode
US4007393A (en) * 1975-02-21 1977-02-08 U.S. Philips Corporation Barium-aluminum-scandate dispenser cathode
EP0333369A1 (fr) * 1988-03-18 1989-09-20 Varian Associates, Inc. Cathode matricielle en solution solide

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7189410B1 (en) 1990-11-27 2007-03-13 The American National Red Cross Supplemented and unsupplemented tissue sealants, methods of their production and use
EP0757370A1 (fr) * 1995-07-31 1997-02-05 Philips Patentverwaltung GmbH Tube à décharge électrique ou lampe à décharge et cathode à réserve comprenant du scandate
WO2000028566A1 (fr) * 1998-11-09 2000-05-18 Samsung Sdi Co., Ltd. Unite de cathode a chauffage direct et canon a electrons l'utilisant
US8518433B2 (en) 2003-12-11 2013-08-27 Zimmer, Inc. Method of treating an osteochondral defect
US8524268B2 (en) 2003-12-11 2013-09-03 Zimmer, Inc. Cadaveric allogenic human juvenile cartilage implant
US8652507B2 (en) 2003-12-11 2014-02-18 Zimmer, Inc. Juvenile cartilage composition
US8765165B2 (en) 2003-12-11 2014-07-01 Zimmer, Inc. Particulate cartilage system
US8784863B2 (en) 2003-12-11 2014-07-22 Zimmer, Inc. Particulate cadaveric allogenic cartilage system
US8834914B2 (en) 2003-12-11 2014-09-16 Zimmer, Inc. Treatment methods using a particulate cadaveric allogenic juvenile cartilage particles
EP1705684A1 (fr) * 2005-03-22 2006-09-27 ICT Integrated Circuit Testing Gesellschaft für Halbleiterprüftechnik mbH Emetteur stabilisé et méthode pour le stabiliser
US8480757B2 (en) 2005-08-26 2013-07-09 Zimmer, Inc. Implants and methods for repair, replacement and treatment of disease
US8497121B2 (en) 2006-12-20 2013-07-30 Zimmer Orthobiologics, Inc. Method of obtaining viable small tissue particles and use for tissue repair
US9138318B2 (en) 2007-04-12 2015-09-22 Zimmer, Inc. Apparatus for forming an implant
US10167447B2 (en) 2012-12-21 2019-01-01 Zimmer, Inc. Supports and methods for promoting integration of cartilage tissue explants

Also Published As

Publication number Publication date
JPH0785775A (ja) 1995-03-31
EP0641007A3 (fr) 1995-06-21
CN1099903A (zh) 1995-03-08

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