EP0045547B1 - Method of fabricating an electron gun electrode member for a cathode-ray tube and cathode ray tube comprising an electron gun electrode member fabricated by this method - Google Patents

Method of fabricating an electron gun electrode member for a cathode-ray tube and cathode ray tube comprising an electron gun electrode member fabricated by this method Download PDF

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Publication number
EP0045547B1
EP0045547B1 EP81200833A EP81200833A EP0045547B1 EP 0045547 B1 EP0045547 B1 EP 0045547B1 EP 81200833 A EP81200833 A EP 81200833A EP 81200833 A EP81200833 A EP 81200833A EP 0045547 B1 EP0045547 B1 EP 0045547B1
Authority
EP
European Patent Office
Prior art keywords
recess
depression
electron gun
electrode member
coining
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
Application number
EP81200833A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0045547A3 (en
EP0045547A2 (en
Inventor
Floyd Keith Collins
Donald Leroy Say
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.)
Philips ECG Inc
Original Assignee
Philips ECG Inc
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 Philips ECG Inc filed Critical Philips ECG Inc
Publication of EP0045547A2 publication Critical patent/EP0045547A2/en
Publication of EP0045547A3 publication Critical patent/EP0045547A3/en
Application granted granted Critical
Publication of EP0045547B1 publication Critical patent/EP0045547B1/en
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • 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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/48—Electron guns
    • H01J29/488—Schematic arrangements of the electrodes for beam forming; Place and form of the elecrodes

Definitions

  • the invention relates to a method of fabricating a cathode-ray tube comprising in an evacuated envelope an electron gun to generate an electron beam and a target for receiving said electron beam, the electron gun including a cathode and at least two grid electrodes, a discretely configurated beam shaping region being fabricated in at least one of the grid electrodes, said region having a one-piece effectual portion presenting upper and lower surfaces defining a material thickness therebetween.
  • Such cathode-ray tubes are used to display, for example, television pictures or are used in an oscilloscope.
  • the target is a display screen having a phosphor layer, for example, in a black-and-white display tube or in an oscilloscope tube, or having a pattern of phosphor elements luminescing in different colours in a colour display tube.
  • Such a tube may also be used as a camera tube.
  • the target is a photosensitive layer, for example, a photoconductive layer.
  • the spot formed when the electron beam impinges on the target must have predetermined, generally small, dimen- signs and the haze surrounding the target should be minimum.
  • Some beam shaping electrodes have been manufactured as two-piece structures in an effort to achieve the desired beam forming characteristics.
  • the article "30AX Self-aligning 110° in-line color TV display" in IEEE Transactions on Consumers Electronics, Vol. CE-24 No. 3, August 1978, pp. 481-487 discloses beam shaping electrodes constructed of two superimposed rectangularly slotted elements affixed in orthogonal relationship to provide a substantially square aperture therethrough. Through these slots the first grid electrode, in cooperation with the cathode, forms a first electrostatic quadrupole lens field and, in cooperation with the second grid electrode, forms a second electrostatic quadrupole lens field rotated 90° with respect to the first electrostatic quadrupole lens field.
  • the electron beam is focused in two focal lines by said lens fields so that the mutual repelling of the electrons (space charge repelling) becomes less than in the case of one concentrated stigmatic cross-over.
  • space charge repelling space charge repelling
  • Another object of the invention is to provide a method of fabricating a one-piece beam shaping electron gun electrode that evidences improved beam forming properties.
  • such a method comprises the steps of coining an elongated recess inward from said upper surface; coining a depression inward from said lower surface in opposed orientation to said recess coining to expedite a flow of electrode material to the upper coining region, thereby promoting the formation of a sub stantially sharp perimetrical edge in at least the central region of said recess shaping; and forming an aperture through the residual electrode material intermediate the bottoms of said coined recess and said coined depression to complete said beam shaping configuration.
  • the electrode fabrication procedure utilizing the aforementioned opposed coining makes the electrode material flow in a manner to assure the formation of a beneficially sharp perimetrical edge at least partially about the upper surface related recess.
  • This sharp edge perimeter in the region of the aperture, markedly augments the beam-shaping properties of the configuration, thereby promoting an improved lensing effect which beneficially modifies the cross-sectional shaping of the beam in the desired manner.
  • the electrode is also comparatively thin in the region of the aperture.
  • FIG. 1 the essentials of a plural in-line beam color cathode ray tube construction 11 are shown.
  • the encompassing envelope is comprised of an integration of neck 13, funnel 15 and face panel 17 portions.
  • a patterned cathodoluminescent screen 19 of color-emitting phosphor areas is disposed on the interior surface of the viewing panel 17 as an array of definite stripes or dots, in keeping with the state of the art.
  • a multiple apertured structure 21, in this instance a shadowmask, is spatially related to the patterned screen; such being secured within the panel by conventional means, not shown.
  • an electron gun assembly 23 Positioned within the neck portion 13 of the envelope is an electron gun assembly 23 comprised of several related electron guns, each of which produces a respective electron beam 25, 27 and 29. While not shown, each of these individual guns includes a cathode and a plurality of sequentially arranged cooperating electrode elements which are formed and spaced to achieve emission, formation, acceleration and focusing of the respective electron beam in a manner to properly impinge the screen 19.
  • a deflection yoke 31 Positioned externally of the tube 11 is a deflection yoke 31 which deflects the beams in a determined manner to provide an image display raster upon the screen.
  • FIG. 2 where is shown an exemplary enlarged sectional view of the rear beam forming region of one of the electron guns of the gun assembly 23.
  • This shown portion of the gun structure includes a thermionic cathode structure 35 having external electron emissive material 37 terminally disposed thereon, such being activated by an internally positioned heating element 39.
  • a first or control grid electrode (G1) 41 Positioned adjacent thereto is a first or control grid electrode (G1) 41 having a one-piece effectual portion 43 transversely oriented to the path of the beam of electrons 45.
  • This effectual portion evidences an upper surface 47 and a lower surface 49, such defining a material thickness "T" therebetween.
  • the shown effectual portion 43 of the control electrode 41 may be an element of several electrode constructions.
  • it can be the bottom part of an individual cup-shaped (G1) member, or a substantially planar dish-shaped portion of an integrated (G1) assembly utilizing a common grid plane for a plurality of guns.
  • the invention relates to the improved beam shaping region regardless of the over-all construction of the electrode.
  • the improved beam shaping region 51 Formed in the electrode effectual portion 41 of the control electrode is the improved beam shaping region 51, which, on conjunction with the spatially related apertured second or screen grid electrode (G2) 53 in an operating gun, provides an initial beam lensing influence in the inter-electrode spacing 54 therebetween.
  • the contoured configuration of the (G1) beam shaping region 51, adjacent the aperture 55 therethrough, and the related apertured effectual portion 57 of the second (G2) electrode, together influence shaping of the array of equipotential lines of force constituting the lensing an a manner ho beneficially modify the shaping of the beam bundle of electrons 45 passing therethrough.
  • the improved configurated beam shaping region in the control electrode 41 has an elongated recess 59 formed, as by coining, inward from the upper surface 47 thereof.
  • the term "coining” as used herein refers to the deformation of material by applied pressure, whether or not the deformed material is contained in a die cavity.
  • This recess which is free of surface imperfections, has a defined width "W", length "L” and depth “D", and as exemplarily shown, is substantially rectangular in shape.
  • W width
  • L length
  • D depth
  • This recess which is free of surface imperfections, has a defined width "W”, length "L” and depth "D”, and as exemplarily shown, is substantially rectangular in shape.
  • the desired lensing effects may require a more ovate modified shaping.
  • this recess evidences a substantially sharp perimetrical edge 61 at least partially thereabout. This is usually difficult to achieve in a stamping or coining operation per se since such pressure techniques tend to form a slightly rolled or radiused
  • a depression 63 is formed, as by coining, inward from the lower surface 49 of the control electrode 41 in opposed orientation to the upper surface-related recess 59.
  • These upper and lower related coining operations produce a beneficial flow of electrode material.
  • This lower surface depression is exemplarily shown as being circular in shape, but it too, may be of a modified ovate shaping. Its diameter or longest lateral dimension "B" should be sufficient to provide a flow of material to at least the central perimetrical region of the related recess 59.
  • the residual electrode material 64 intermediate the bottom 65 of the recess and the bottom 67 of the depression evidences a thickness "t".
  • the depth "D" of the recess 59 does not exceed the thickness "t" of the residual material, and the depth “d” of the depression 63 is less than the thickness "t” of the residual material.
  • the depression 63 is dimensioned to accommodate positioning of the cathode 35 in close spatial relationship with the bottom surface of the control (G1) electrode. Such accommodation tends to effect a degree of shielding for the emissive surface of the cathode.
  • An aperture 55 is formed through the residual material 64 in symmetrical relationship with the recess 59 and the depression 63 to complete the improved configurated beam shaping region 51.
  • This aperture is exemplarily shown as being circular in shaping, but such is not to be considered limiting. Regardless of its shaping, its width or diametrical dimension "A”, is slightly less than the width dimension "W" of the recess.
  • Such dimensional relationship allows a clean aperture to be formed through the residual material 64 without damaging the sharp perimetrical edge 61 of the recess or scarring the sidewalls thereof.
  • Fig. 5 wherein there is shown a grid blank for the control (G1) electrode 41.
  • the effectual portion is defined by the perimeter 69, in this instance circular, with the upper surface 47 and the lower surface 49 threreof defining a given thickness therebetween.
  • This blank is positioned in a tooling arrangement 71 as shown in Fig. 6. With the blank resting on a bottom anvil member, 72 a top forming die 73, having a defined projection 75, is pressured against an appropriate part of the upper surface of the ele- trode blank 41 in a manner to coin the substantially rectangular recess 59 therein.
  • a movable coining die 77 contained for sliding operation within anvil member 72, is pressured against the lower surface 49 of the blank to coin the substantially circular depression 63 in the lower surface thereof.
  • the resultant flow of material effected by the coining of the depression forces some of the flow material to the top forming die to fill in the inherently round edge about the recess 59, thereby promoting the formation of the substantially sharp perimetrical edge 61 about at least the central portion thereof.
  • the beam aperture 55 is thence provided in the coined region, being oriented as heretofore described. Thus, the forming of the configurated beam shaping region is completed.
  • the electron gun electrode structure of cathode ray tube fabricated by the method according to the invention incorporates the forming of a discretely configurated beam shaping region which contributes to improved lensing influencing the initial shaping of the beam.
  • the economical and expeditious double coined fabrication procedure assures the achievement of the beneficially sharp perimetrical edge in at least the critical region of the recess portion of the configuration.
  • the one piece electrode structure reduces manufacturing costs, and overcomes further disadvantages of the two-piece structures of the prior art by eliminating the inaccuracies of multiple piece assembly and the possible presence of weld burrs on critical surfaces.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
  • Microwave Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
EP81200833A 1980-08-04 1981-07-21 Method of fabricating an electron gun electrode member for a cathode-ray tube and cathode ray tube comprising an electron gun electrode member fabricated by this method Expired EP0045547B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US17516580A 1980-08-04 1980-08-04
US175165 1980-08-04

Publications (3)

Publication Number Publication Date
EP0045547A2 EP0045547A2 (en) 1982-02-10
EP0045547A3 EP0045547A3 (en) 1982-06-23
EP0045547B1 true EP0045547B1 (en) 1984-09-26

Family

ID=22639203

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81200833A Expired EP0045547B1 (en) 1980-08-04 1981-07-21 Method of fabricating an electron gun electrode member for a cathode-ray tube and cathode ray tube comprising an electron gun electrode member fabricated by this method

Country Status (5)

Country Link
EP (1) EP0045547B1 (enrdf_load_stackoverflow)
JP (1) JPS5763746A (enrdf_load_stackoverflow)
CA (1) CA1184234A (enrdf_load_stackoverflow)
DE (1) DE3166330D1 (enrdf_load_stackoverflow)
ES (1) ES8204880A1 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3617432A1 (de) * 1986-05-23 1987-11-26 Standard Elektrik Lorenz Ag Elektronenstrahlerzeugungssystem

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1170150B (it) * 1982-07-19 1987-06-03 Rca Corp Griglia dotata di aperture per cannoni elettronici e metodo di fabbricazione della stessa
IT1176203B (it) * 1983-06-27 1987-08-18 Rca Corp Tubo a raggi catodici con un cannone elettronico presentante una regione di formazione di un fascio astigmatico
JP2672502B2 (ja) * 1987-01-26 1997-11-05 株式会社日立製作所 カラーブラウン管電子銃用電極の製造方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2052845A (en) * 1979-05-18 1981-01-28 Hitachi Ltd Electrode for a colour crt electron gun

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2935636A (en) * 1955-10-31 1960-05-03 Rca Corp Electron gun structure
US2971108A (en) * 1958-09-26 1961-02-07 Sylvania Electric Prod Electron discharge device
US3628077A (en) * 1970-02-26 1971-12-14 Sylvania Electric Prod Electron gun having concave coined grid and annular rib
US4071932A (en) * 1976-10-28 1978-02-07 Standaart Adrian W Method of making electron guns for cathode ray tubes and the like

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2052845A (en) * 1979-05-18 1981-01-28 Hitachi Ltd Electrode for a colour crt electron gun

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"30 AX self-aligning 110 grad in line colour TV Display", in IEEE Trans. on Cons. Elec., vol. CE24 no. 3, pp. 481-487 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3617432A1 (de) * 1986-05-23 1987-11-26 Standard Elektrik Lorenz Ag Elektronenstrahlerzeugungssystem

Also Published As

Publication number Publication date
JPS5763746A (en) 1982-04-17
DE3166330D1 (en) 1984-10-31
JPH0312417B2 (enrdf_load_stackoverflow) 1991-02-20
ES504476A0 (es) 1982-05-01
CA1184234A (en) 1985-03-19
EP0045547A3 (en) 1982-06-23
EP0045547A2 (en) 1982-02-10
ES8204880A1 (es) 1982-05-01

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