US3701065A - Color picture tube beam convergence apparatus - Google Patents

Color picture tube beam convergence apparatus Download PDF

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Publication number
US3701065A
US3701065A US112348A US3701065DA US3701065A US 3701065 A US3701065 A US 3701065A US 112348 A US112348 A US 112348A US 3701065D A US3701065D A US 3701065DA US 3701065 A US3701065 A US 3701065A
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Prior art keywords
neck
tube
discs
disc
convergence apparatus
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Expired - Lifetime
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US112348A
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English (en)
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John Walter Mirsch
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RCA Licensing Corp
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RCA Corp
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Assigned to RCA LICENSING CORPORATION, TWO INDEPENDENCE WAY, PRINCETON, NJ 08540, A CORP. OF DE reassignment RCA LICENSING CORPORATION, TWO INDEPENDENCE WAY, PRINCETON, NJ 08540, A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: RCA CORPORATION, A CORP. OF DE
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    • 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
    • H01J29/70—Arrangements for deflecting ray or beam
    • H01J29/701—Systems for correcting deviation or convergence of a plurality of beams by means of magnetic fields at least
    • H01J29/702—Convergence correction arrangements therefor
    • H01J29/703—Static convergence systems

Definitions

  • the beam convergence apparatus of this invention has particular utility with a color picture tube of the socalled in-line electron beam type in which a plurality of electron beams emanate from the neck of the tube nominally in a common plane.
  • the convergence apparatus comprises two low permeability permanent magnet structures disposed respectively on opposite sides of the tube neck. These magnet structures produce respective fields by which to influence the electron beams appropriately to effect their substantial convergence at the viewing screen of the tube.
  • the magnet, structures are provided with means for suitably adjusting the strength and the orientation of the produced fields.
  • each of the magnet structures includes a pair of diametrically magnetized ceramic ferrite discs coaxially disposed relative to one another.
  • each of the structures is rotatable as a unit about an axis parallel to the longitudinal axis of the tube to adjust the orientation of the produced field.
  • FIG. 1 is a diagrammatic top view of a color picture tube having three in-line electron guns and showing the general positions of the beam convergence apparatus of this invention in relation to other adjuncts used in the operation of the tube;
  • FIG. 2 is a fragmentary sectional view taken on the line 2-2 of FIG. 1 and showing the rear end view of the beam convergence apparatus;
  • FIG. 3 is an enlarged view of one of the permanent magnet structures of the beam convergence apparatus
  • FIG. 4 is an exploded view of the magnet structure of FIG. 3 and showing the relationship of the components of the magnet structure;
  • FIG. 5 is a sectional view taken on the line 5-5 of FIG. 4 and showing the details ofone of the magnetretaining collars of the apparatus;
  • FIG. 6 is a sectional view taken on the line 6--6 of FIG. 4 and showing the configuration and magnetization of one of the magnet components of the beam convergence apparatus;
  • FIG. 7 is a diagrammatic representation of the operation of the beam convergence apparatus of the invention.
  • the three beam shadow mask type of color picture tube 11, with whichthe beam convergence apparatus of the invention is used has a relatively large flared front section 12 and a relatively small cylindrical neck section 13.
  • the face plate 14 at the front of the flared section 12 has formed on its rear surface a fluorescent screen 15 comprising a multiplicity of triads of phosphor dots which are excitable by respective electron beams to produce light of three difierent colors such as red, green and blue.
  • a shadow mask 16 having a plurality of apertures aligned with the triads of phosphor dots of the screen 15 is mounted in back of the screen and functions, in cooperation with other elements of the tube, to direct the three electron beams to their respective phosphor dots.
  • Three electron guns 17, 18 and 19 are mounted in the neck section 13 of the picture tube 11. to produce, when suitably energized, the three electron beams for excitation of the screen 15.
  • the electron guns 17, 18 and 19 are located in a common horizontal plane in a so-called in-line arrangement.
  • a deflection yoke 21 is mounted externally of the tube 11 in the region in which the neck section 13 merges with the flared section 12.
  • the beam convergence apparatus 22 comprising this invention is located on opposite sides of the neck section 13 immediately to the rear of the deflection yoke 21.
  • a color purity device 23 is mounted still further to the rear on the neck section 13 of the tube 11.
  • FIG. 2 rear view of the convergence apparatus 22 shows its two magnet structures 24 and 25 on opposite sides of the picutre tube neck 13 and centered, as an example, in the same horizontal plane with the three electron beam-producing guns l7, l8 and 19.
  • the magnet structures 24 and 25 are mounted, in a manner to be described presently, in respective halves 26a and 26b of a non-magnetic plate 26 which effectively encircles the tube neck 13. Because it is desirable to position the convergence apparatus, including the magnet structures 24 and 25, immediately to the rear of the deflection yoke 21 the plate 26 may also serve as the terminal board for the yoke windings.
  • the two mounting half-plates 26a and 26b may be secured to one another by any suitable means such as a pair of spring clips 27.
  • FIG. 3 an assembled profile view (enlarged to approximately four times actual size) of one of the magnet structures 24 is shown as it is mounted on the halfplate 260.
  • Both of the half-plates 26a and 26b are constructed of non-magnetic material such as lucite for example.
  • Two'magnet discs (not shown in this figure) are supported within respective non-magnetic annular retaining collars 28 and 29 and are coaxially mounted on a non-magnetic flanged spindle 31 which extends through the half-plate 26a.
  • the retaining collars 28 and 29 have centrally disposedholes 32 and 33, respectively, to snugly receive ceramic magnet discs 34 and 35.
  • the thicknesses of the magnet discs 34 and 35 are substantially the same as those of their respective retaining collars 28 and 29 so that the faces of the magnet discs effectively abut one another when assembled as shown in FIG. 3.
  • the magnet discs 34 and 35 have centrally disposed holes 36 and 37 respectively for snug mounting on the spindle 31. With the magnet discs 34 and 35 respectively supported within the holes 32 and 33 of the retaining collars 28 and 29, the spindle 31 extends through the disc holes 36 and 37 into a hole 38 in the half-plate 26a.
  • the spindle 31 has a flange 39 so as to securely mount the components of the magnet structure 24 on the half-plate 26a as shown in the assembly on FIG. 3.
  • the retaining collars 28 and 29 and their respectively supported magnet discs 34 and 35 are adjustably rotatable about an axis 40 which is parallel to the longitudinal axis of the picture tube 11. It will be understood that the magnet structure 25 of FIG. 2 is similarly constructed.
  • FIG. view of the retaining collar 29 shows the peripheral edge of its flange portion to be notched such as by gear teeth 41.
  • the purpose of the gear teeth 41 is to facilitate manipulative rotation of the collar and its supported magnet disc 35 about the spindle 31.
  • Each of the magnet discs may be formed of a ceramic material such as plastic barium ferrite. Such a material has a relatively low permeablility and, when diametrically magnetized as indicated in this figure, is more strongly magnetized on one face than on the other.
  • the mounting of the magnet disc 35 of FIG. 6 in the retaining collar 29 of FIG. 5 should be such that the stronger magnetized face is away from the notched flange 41 of the retaining collar.
  • the magnet disc 34 should be similarly mounted in the collar 29. In this way the stronger magnetized faces of the magnet discs 34 and 35 will abut one another when the structure is assembled as indicated in FIGS. 3 and 4, thereby producing an effective field for electron beam convergence.
  • the strength of the resultant beam-controlling field is adjusted by manipulation of the notched peripheral edges, such as the edge 41 of the collar 29, of the two retaining collars 28 and 29 relative to one another.
  • the resultant field has maximum strength.
  • a minimum strength field is produced by aligning the N pole of one magnet disc with the S pole of the other disc.
  • Field strengths of intermediate values are produced by relative positions of the magnet discs 34 and 35 intermediate of the two described extreme positions.
  • the orientation of the resultant field is determined by the angular positioning of the mutually adjusted magnet discs 34 and 35 relative to the supporting spindle 31.
  • FIG. 7 A graphical example of the manner in which the convergence apparatus of this invention enables the accomplishment of the desired result is depicted in FIG. 7. It will be assumed that the desired convergence of the electron beams at the viewing screen can be achieved by positioning the beams symmetrically about the longitudinal tube axis in a common horizontal plane indicated by the broken line 42. It will also be assumed that the beams issue from their respective electron guns in the relative positions represented by the squares 43, 44 and 45. In this assumed example the middle beam is in its desired position substantially at the center of the tube neck 13 and in the common plane 42 as indicated by the circle 44'. The left-hand beam position 43, however, is above the common plane 42 and closer to the center of the tube neck 13 than it should be for effective convergence with the middle beam at the viewing screen. Also, the right-hand beam position 45 is below the common plane 42 and farther from the tube neck center than it should be for convergence with the middle beam.
  • the rotation of the complete magnet structures 24 and 25 about the respective axes 40 and 40' causes the associated electron beams to be moved in substantially circular patterns.
  • the magnitude of each circular pattern is determined by the rotational adjustment of the two component magnet discs (such as the discs 34 and 35 of FIG. 4) relative to one another.
  • the left-hand beam for example, may be positioned anywhere on the circular pattern 46 by a suitable rotational adjustment of the magnet structure 24 about the axis 40. Such latter adjustment determines the particular orinentation of the produced field and, thus, controls the direction in which the beam is moved to a selected position on the circular pattern 46. In the case of the left-hand beam, it may be moved from the position 43 to the position 43' efiectively along the line 47.
  • the length of the line is determined by the strength of the produced field which is a function of the relative rotational adjustments of the component magnet discs of the structure 24.
  • the angular relationship of the line 47 to the common plane 42 is determined by the orientation of the produced field which is selected by the rotational adjustment of the magnet structure 24 about the axis 40.
  • the right-hand beam may be effectively moved from position 45 to position 45
  • this stronger field must be oriented by a rotational adjustment of the magnet structure 25 about the axis 40' so that the diametral line 49, representing the effective path of beam movement, is angularly related to the common plane 42 in a way to cause the beam to be moved from position 45 to position 45.
  • the magnet structures 24 and 25 remain always at the same distance from the electron beams, the fields produced thereby do not spray out to adversely affect the beams in more sensitive areas. While the magnet structures are shown herein mounted in the common plane of the beams, they are not necessarily limited to such positions because of the fact that they operate in such a manner that coordinate X and Y motions of the beams are produced. Hence, the angular positioning about the longitudinal axis of the picture tube 11 of the magnet structures 24 and 25 is not critical.
  • a tri-beam color kinescope having a screen for display of a color picture in response to the scanning thereof by a plurality of electron beams in a succession of substantially parallel line sweeps, and having a cylindrical neck enclosing a trio of in-line beam paths, a central one of said in-line beam paths substantially coinciding with the longitudinal axis of said neck with the remaining outer ones of said in-line beam paths being substantially symmetrically disposed on opposite sides of said axis, and with all of said in-line beam paths traversing a region of the interior of said neck which is free of readily magnetizable structures;
  • shifting means for shifting one of said outer beam paths in a selectable one of a plurality of directions inclusive of directions parallel to, perpendicular to, and diagonal to the direction of said line sweeps said shifting means comprising a first adjustable permanent magnet means, mounted on the exterior of said tube neck for positioning on one side of said tube neck region in a first location closely adjacent one of said outer beam paths, for producing a magnetic field intersecting with primary influence said one of said outer beams with a selectable one of a plurality of directions inclusive of directions parallel to, perpendicular to, and diagonal to the direction of said line sweeps; and
  • said additional shifting means comprising second adjustable permanent magnet means, mounted on the exterior of said tube neck for positioning on the side of said tube neck region opposite to said one side in a secondv location closely adjacent said other of said outer beam paths, for producing a magnetic field intersecting with primary influence said other of said outer beams with a selectable one of a plurality of directions inclusive of directions parallel to, perpendicular to, and diagonal to the direction of said line sweeps;
  • each of said first and second permanent magnet field producing means is independently adjustable.
  • Beam convergence apparatus for a color picture tube having a plurality of electron beams emanating fromthe neck of said tube in a nominally common plane and subject to passage toward the screen of said tube through a region of said neck free of the presence of internal magnetizable pole piece structures, said apparatus comprising:
  • each of said magnet structures includes a pair of magnetized discs of low permeability material coaxially disposed relative to one another in a mounting therefor,
  • each disc being magnetized on a diameter
  • said discs being rotatable relative to one another to vary the strength of the produced magnetic field.
  • each of said magnet structures is rotatable about an axis that is parallel to the longitudinal axis of said tube to vary the orientation of the produced magnetic field.
  • said magnetized discs are ceramic of barium ferrite material with the magnetization being stronger on one face thereof than on the other, and
  • each of said magnet structures being assembled with the stronger magnetized faces of said respective discs abutting one another.
  • said disc mounting includes a non-magnetic spindle
  • said discs are provided with central transverse holes to snugly fit over said spindle.
  • said disc mounting also includes a non-magnetic annular retaining collar having an inside diameter so related to the outside diameter of said disc that the disc is firmly secured within the collar.
  • said disc mounting further includes a non-magnetic plate disposed around the neck of said tube normal to the longitudinal tube axis, and transverse holes through said plate on opposite sides of said tube neck in said common plane to receive said respective disc-supporting spindles.
  • each of said disc-supporting spindles has a flange at one end to constrain said disc-retaining collars to rotary movements between said flange and said plate.
  • said disc-retaining collars have notched peripheral edges by which to effect said field strength and orientation varying rotations of said discs.
  • a first pair of magnetized discs of low material a second pair of magnetized discs of low material; an apertured mount of non-magnetizable material for said first and second disc pairs, said tube neck being received within the aperture of said the mount, and said mount being positioned along the neck axis so as to encircle said structure-free region of said neck; and means for rotatably supporting each of said pair of discs on said mount in respective diametrically opposed positions spaced from said mount aperture, the discs of each pair being coaxially disposed and subject to individual rotation about an axis substantially parallel to the axis of said neck.

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  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
US112348A 1971-02-03 1971-02-03 Color picture tube beam convergence apparatus Expired - Lifetime US3701065A (en)

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Application Number Priority Date Filing Date Title
US11234871A 1971-02-03 1971-02-03

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US (1) US3701065A (xx)
JP (1) JPS569829B1 (xx)
AU (1) AU476702B2 (xx)
CA (1) CA948261A (xx)
DE (1) DE2204100C3 (xx)
ES (1) ES399450A1 (xx)
FR (1) FR2124249B1 (xx)
GB (1) GB1376844A (xx)
HK (1) HK3080A (xx)
IT (1) IT947173B (xx)
NL (1) NL175117C (xx)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3793602A (en) * 1973-04-13 1974-02-19 Gen Electric Convergence device for short neck in-line cathode ray tube
US3808570A (en) * 1972-03-20 1974-04-30 Rca Corp Static convergence device for electron beams
US3852693A (en) * 1973-12-04 1974-12-03 W Schwalm Magnetic convergence device for cathode ray tubes
US3858134A (en) * 1974-06-03 1974-12-31 Gte Sylvania Inc Horizontal convergence means for in-line beam cathode ray tube
US3913043A (en) * 1973-10-10 1975-10-14 Philips Corp Deflection device for a color television display tube
US4122421A (en) * 1975-11-21 1978-10-24 Indesit Industria Elettrodomestici Italiana S.P.A. Device for the control of electron beams of a cathode ray tube
US4198614A (en) * 1978-11-06 1980-04-15 Rca Corporation Deflection yoke assembly including a beam positioning magnet arrangement
DE3038621A1 (de) * 1979-10-19 1981-05-21 Naamloze Vennootschap Philips' Gloeilampenfabrieken, Eindhoven Vorrichtung zum wiedergeben farbiger bilder
US4490703A (en) * 1982-07-28 1984-12-25 Ball Corporation Multipole magnet for electron beam correction
US5399933A (en) * 1993-05-20 1995-03-21 Chunghwa Picture Tubes, Ltd. Magnetic beam adjusting rings with different thickness

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4100518A (en) * 1976-06-21 1978-07-11 Rca Corporation Eccentric convergence apparatus for in-line beam cathode ray tubes

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2854598A (en) * 1955-11-21 1958-09-30 Baermann Max Magnetic field adjuster for television picture tubes
US2854607A (en) * 1952-11-18 1958-09-30 Philips Corp Magnetic device
US2887598A (en) * 1956-04-16 1959-05-19 Rca Corp Plural gun cathode ray tube
US3290532A (en) * 1964-04-23 1966-12-06 Rca Corp Conjointly-movable, plural magnet means for blue lateral correction in color kinescopes
US3430099A (en) * 1966-08-23 1969-02-25 Gen Electric Simplified deflection system for plural in-line beam cathode ray tube
US3453472A (en) * 1967-01-18 1969-07-01 Sylvania Electric Prod Convergence apparatus for multi-gun cathode ray tubes
US3553523A (en) * 1969-06-12 1971-01-05 Sylvania Electric Prod Convergence means for plural in-line beam cathode ray tube

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3354336A (en) * 1965-06-30 1967-11-21 Zenith Radio Corp Ring magnetized across thickness with two diametrically opposed and oppositely oriented groups of magnetic pole pairs
DE1285516B (de) * 1967-12-11 1968-12-19 Matsushita Electric Ind Co Ltd Statische Konvergenzvorrichtung fuer Farbfernsehempfaenger mit Farbbildwiedergaberoehren
US3639796A (en) * 1968-03-11 1972-02-01 Sony Corp Color convergence system having elongated magnets perpendicular to plane of plural beams

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2854607A (en) * 1952-11-18 1958-09-30 Philips Corp Magnetic device
US2854598A (en) * 1955-11-21 1958-09-30 Baermann Max Magnetic field adjuster for television picture tubes
US2887598A (en) * 1956-04-16 1959-05-19 Rca Corp Plural gun cathode ray tube
US3290532A (en) * 1964-04-23 1966-12-06 Rca Corp Conjointly-movable, plural magnet means for blue lateral correction in color kinescopes
US3430099A (en) * 1966-08-23 1969-02-25 Gen Electric Simplified deflection system for plural in-line beam cathode ray tube
US3453472A (en) * 1967-01-18 1969-07-01 Sylvania Electric Prod Convergence apparatus for multi-gun cathode ray tubes
US3553523A (en) * 1969-06-12 1971-01-05 Sylvania Electric Prod Convergence means for plural in-line beam cathode ray tube

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3808570A (en) * 1972-03-20 1974-04-30 Rca Corp Static convergence device for electron beams
US3793602A (en) * 1973-04-13 1974-02-19 Gen Electric Convergence device for short neck in-line cathode ray tube
US3913043A (en) * 1973-10-10 1975-10-14 Philips Corp Deflection device for a color television display tube
US3852693A (en) * 1973-12-04 1974-12-03 W Schwalm Magnetic convergence device for cathode ray tubes
US3858134A (en) * 1974-06-03 1974-12-31 Gte Sylvania Inc Horizontal convergence means for in-line beam cathode ray tube
US4122421A (en) * 1975-11-21 1978-10-24 Indesit Industria Elettrodomestici Italiana S.P.A. Device for the control of electron beams of a cathode ray tube
US4198614A (en) * 1978-11-06 1980-04-15 Rca Corporation Deflection yoke assembly including a beam positioning magnet arrangement
DE3038621A1 (de) * 1979-10-19 1981-05-21 Naamloze Vennootschap Philips' Gloeilampenfabrieken, Eindhoven Vorrichtung zum wiedergeben farbiger bilder
US4490703A (en) * 1982-07-28 1984-12-25 Ball Corporation Multipole magnet for electron beam correction
US5399933A (en) * 1993-05-20 1995-03-21 Chunghwa Picture Tubes, Ltd. Magnetic beam adjusting rings with different thickness

Also Published As

Publication number Publication date
NL175117C (nl) 1984-09-17
DE2204100A1 (de) 1972-08-10
GB1376844A (en) 1974-12-11
NL7201353A (xx) 1972-08-07
AU476702B2 (en) 1976-09-30
AU3793772A (en) 1973-07-19
FR2124249A1 (xx) 1972-09-22
DE2204100C3 (de) 1982-02-25
NL175117B (nl) 1984-04-16
ES399450A1 (es) 1974-10-16
DE2204100B2 (de) 1981-07-02
HK3080A (en) 1980-02-01
JPS569829B1 (xx) 1981-03-04
CA948261A (en) 1974-05-28
FR2124249B1 (xx) 1978-04-14
IT947173B (it) 1973-05-21

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Owner name: RCA LICENSING CORPORATION, TWO INDEPENDENCE WAY, P

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:RCA CORPORATION, A CORP. OF DE;REEL/FRAME:004993/0131

Effective date: 19871208