US3899761A - Colour picture tubes containing an in-line type electron gun assemblies - Google Patents

Colour picture tubes containing an in-line type electron gun assemblies Download PDF

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Publication number
US3899761A
US3899761A US444275A US44427574A US3899761A US 3899761 A US3899761 A US 3899761A US 444275 A US444275 A US 444275A US 44427574 A US44427574 A US 44427574A US 3899761 A US3899761 A US 3899761A
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United States
Prior art keywords
pole piece
disposed
electron gun
segments
convergence
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Expired - Lifetime
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US444275A
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English (en)
Inventor
Masaaki Yamauchi
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Hitachi Ltd
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Hitachi Ltd
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Publication date
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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
    • H01J29/707—Arrangements intimately associated with parts of the gun and co-operating with external magnetic excitation devices

Definitions

  • ABSTRACT In an in-line type colour picture tube provided with dynamic and static convergences there is provided a pole piece assembly disposed in the plane of convergence adjustment.
  • the pole piece assembly comprises first and second pairs of pole piece segments which are disposed silbstantially at right angles with each other.
  • the second pair of pole piece segments is disposed in a direction coinciding with the direction of vertical deflection of the electron beams.
  • the tasters of three electron beams .do not generally coincide with each other in the vertical and horizontal peripheries of the fluorescent screen.
  • the deflection sensitivity of the electron beam emanated from the central electron gun to the vertical deflection field is smaller than that of the electron beams emanated from the electron guns on both sides. Such a phenomenon is caused by the characteristic of the deflection yoke.
  • shielding of the electron beam of the central electron gun from the field for the static convergence also shields a portion of the vertical and horizontal deflection fields with the result that the raster of the central electric field will be shifted toward the center of the fluorescent screen.
  • the deflection sensitivity of the electron beam from the central electron gun is decreased relative to the case wherein the electron beam is not magnetically shielded both in the horizontal and vertical directions. If the dynamic convergence were to be applied under these conditions it would be necessary to supply a current having an asymmetrical waveform with respect to the direction of the horizontal deflection of the electron beams emanated from the electron guns on both sides. Further, it is necessary to provide a complicated dynamic convergence circuit which increases the deflection sensitivity of the electron beam from the central electron gun for the vertical deflection or decreases the deflection sensitivity of the electron beams emanated from the electron guns on both sides.
  • the vertical deflection field applied to the electron beams from the electron guns on both sides near the pole pieces can be decreased relative to that of the case wherein no pole piece is used and the vertical deflection field applied to the electron beam from the central electron gun can be increased relative to that of the case wherein no pole piece is used thereby compensating for the difference in the vertical deflection sensitivity and eliminating the difference in the horizontal deflection sensitivity caused by the magnetic shield.
  • Another object of this invention is to provide an improved in-line type colour picture tube including a convergence pole piece assembly capable of eliminating the compensation for the dynamic convergence for the vertical deflection and which permits use of currentof a symmetrical waveform for the dynamic convergence in the horizontal direction for the electron beams from the electron guns on the opposite sides.
  • Still another object of this invention is to provide an in-line type colour picture tube provided with convergence pole pieces of the improved construction which do not intercept the fields of the static and dynamic convergences for the electron beams emanating from. the electron guns on both sides. 7
  • Yet another object of this invention is to provide an in-line type colour picture tube having convergence pole pieces which are simple in construction and can be mounted readily.
  • an in-line type colour picture tube of the type comprising three electron guns arranged on a straight line, and means for adjusting on substantially the same plane the dynamic convergence and the static convergence provided for concentrating three electron beams emanated from the three electron guns at a point on the fluorescent screen of the colour picture tube, characterized in that there is provided a pole piece assembly disposed in said plane of convergence adjustment, that the pole piece assembly includes a first pair of pole piece segments and a second pair of pole piece segments, that the pairs are disposed substantially at right angles with each other, and that the first pair of pole piece segments is disposed in a direction coinciding with the direction of vertical deflection of the electron beams.
  • FIG. 1 is a diagrammatic representation of a portion of an in-line type colour picture tube
  • FIG. 2 is a diagram showing typical rasters where no pole piece is used
  • FIG. 3 is a diagram showing typical rasters where the central electron gun is magnetically shielded
  • FIG. 4 is a perspective view of one example of the pole pieces embodying the invention.
  • FIG. 5 is a cross-sectional view of the assembly of the pole pieces shown in FIG. 4;
  • FIG. 6 is a diagram to explain the operation of this invention.
  • FIG. 7 is a diagram showing the rasters appearing in the colour picture tube embodying the invention.
  • FIG. 8 is a diagrammatic representation to explain the operation of this invention.
  • FIG. 1 shows the construction of the deflector of an in-line type colour picture tube
  • electron beams B B and B emanated from electron guns G G and B respectively are corrected by a convergence adjusting member 1 and are then deflected by a deflection yoke 2 so as to scan the entire surface of a fluorescent screen (not shown) of the colour picture tube.
  • the convergence member 1 includes a dynamic convergence adjuster and a static convergence adjuster which are arranged on the same plane.
  • the convergence adjusting member 1 and the deflection yoke 2 are located close to each other the pole pieces (not shown) for field correction which are disposed on substantially the same plane as the convergence adjusting member 1 are subjected to the complicated action of the flux produced by the deflection yoke 2, and the fluxes for providing the dynamic and static convergences.
  • the central electron beam B will be moved by the interference with the flux for effecting the static convergence thus rendering it difficult to adjust.
  • FIG'. 2 shows a manner of misconvergence of the electron beams B, G and R for respective colours at the periphery of the fluorescent screen where no pole piece for field correction is used, such manner representing the characteristic of the deflection yoke.
  • the deflection of the red beam R is not sufficient so that the red beam R is positioned on the inside of the screen with respect to the blue beam B and the green beam G.
  • the red beam R is positioned between the blue beam B and the green beam G.
  • the pole piece assembly of this invention for correcting the magnetic field comprises a first pair of pole piece segments 3 and a second pair of pole piece segments 6.
  • Each pole piece segment 3 is outwardly concave and includes a central fiat portion 3a and inclined portions 3b on both sides thereof.
  • Each pole piece segment 6 comprises an arcuate portion 6a and a flat web 6b extending in the diametrical direction from the center of the arcuate por tion 6a.
  • Pole piece segments 3 and 6 are made of a material of high permeability, for example permalloy, for providing magnetic paths of low reluctance. Accordingly, it is necessary to form portions 3a and 3b and 6a and 6b as integral structures not including any air gap or other region of high reluctance at the interface between these parts.
  • two pole piece segments 3 are disposed symmetrically with their back surfaces opposed to each other and are secured to the inside of a cylindrical cage 5 by means of supporting members 4.
  • the supporting members 4 and the cylindrical cage 5 are required to be made of a material that transmits magnetic flux, non-magnetic stainless steel for example.
  • the pole piece segments 6 are disposed between the spaced pair of segments 3 with their arcuate portions 6a secured to the inside of the cylindrical cage 5.
  • the pairs of segments 3 and 6 are combined to form an assembly wherein a line interconnecting the webs 6b of the segments 6 intersects at right angles with a line interconnecting the centers of the segments 3.
  • the central electron beam R will pass through the center of a space bounded by the segments 3 and 6 whereas the electron beams B and G will pass through the spaces defined by the left and right segments 3 and the cylindrical cage 5.
  • the pole piece segments 3 function to gather the vertical deflection flux VH at the center to increase the vertical deflection sensitivity of the central electron beam, that is the red beam R. This is caused by the fact that a magnetic path having a small relucthe deflection of three electron beams in the horizontal direction will be substantially the same as that of the case wherein no pole is provided.
  • FIG. 7 shows a condition wherein the left and right hand rasters are maintained unchanged but the rasters R along the upper and lower edges are made to coincide with the rasters B and G on the same sides.
  • FIG. 7 shows a condition wherein the left and right hand rasters are maintained unchanged but the rasters R along the upper and lower edges are made to coincide with the rasters B and G on the same sides.
  • Two pairs of pole piece segments 3 and 6 provide the function of the magnetic shield that prevents the flux of an external adjusting member, not shown, from interferring with the central electron beam (red beam R). This function will be described with reference to FIG. 8.
  • FIG. 8 shows the relationship between the static and dynamic convergences and the pole piece sections embodying the invention, in which the lefthand side a shows the function of the dynamic convergence, whereas the righthand side b that of the static convergence.
  • the static convergence is provided by rotating magnets M M M and M for adjusting the polarity and intensity of the flux SH flowing through E shaped magnetic cores of the convergence adjusting member 1 so as to statically coincide the outside beams (green and blue beams B and B with the central beam B
  • the dynamic convergence is provided by passing a current having a parabolic waveform through a coil 8 of the convergence adjusting member 1 from an external source E.C.S.
  • the dynamic convergence flux D which shifts the blue and green electron beams B and B to coincide with the central red beam B
  • the power required for the dynamic convergence may be small. It is necessary to vary the size and configuration of the two pairs of pole piece segments 3 and 6 in accordance with the flux distribution of the external convergence field and the flux distribution of the deflection yoke.
  • the correction of the convergence provided by this invention is most suitable for the convergence of the simple type such as those utilizing saddle type deflection yoke or of the wide angle (110) deflection type.
  • a pair of pole piece segments 3 acts to increase the deflection of the central beam (red beam B in the vertical direction and the other pair of the pole piece segments 6 functions to cause the horizontal deflection flux to act uniformly upon respective electron beams.
  • the fluxes of the dynamic and static convergences from interferring with the central electron beam it is possible to readily adjust the convergence of the colour picture tube.
  • the invention provides an improved colour picture tube in which the adjustment of the convergence can be readily made in a short time even by a unskilled person.
  • an in-line type colour picture tube of the type comprising three electron guns arranged on a straight line, and means for adjusting on substantially the same plane the dynamic convergence and the static convergence provided for concentrating three electron beams emanated from said three electron guns at a point on the fluorescent screen of said colour picture tube
  • the improvement which comprises a pole piece assembly disposed in said plane of convergence adjustment, said pole piece assembly including a first pair of spaced pole piece segments substantially symmetrically disposed with respect to a plane perpendicular to said straight line, which plane passes through the axis of a central electron gun, one of said first paired pole piece segments being disposed between the axes of the central electron gun and an outer electron gun, the other being disposed between the axes of the central electron gun and the other outer electron gun, individual segments of said first paired pole piece segments being disposed also symmetrically with respect to another plane passing through the axes of the three electron guns and opposed to each other by a smaller distance at said straight line than at the extremities remote from said straight line, and a second pair

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  • Video Image Reproduction Devices For Color Tv Systems (AREA)
US444275A 1973-05-04 1974-02-21 Colour picture tubes containing an in-line type electron gun assemblies Expired - Lifetime US3899761A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4911273A JPS5522907B2 (fr) 1973-05-04 1973-05-04

Publications (1)

Publication Number Publication Date
US3899761A true US3899761A (en) 1975-08-12

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ID=12821973

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Application Number Title Priority Date Filing Date
US444275A Expired - Lifetime US3899761A (en) 1973-05-04 1974-02-21 Colour picture tubes containing an in-line type electron gun assemblies

Country Status (6)

Country Link
US (1) US3899761A (fr)
JP (1) JPS5522907B2 (fr)
DE (1) DE2408994C3 (fr)
FR (1) FR2228293B1 (fr)
GB (1) GB1436925A (fr)
IT (1) IT1009332B (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4057747A (en) * 1974-10-14 1977-11-08 Tokyo Shibaura Electric Company, Ltd. In-line plural beam color cathode ray tube having deflection defocus correcting elements
US4232283A (en) * 1979-03-27 1980-11-04 Rca Corporation Electron beam moving apparatus for a color cathode ray tube
US4237437A (en) * 1978-02-06 1980-12-02 U.S. Philips Corporation Deflection unit for color television display tubes
US4257023A (en) * 1977-11-29 1981-03-17 Tokyo Shibaura Denki Kabushiki Kaisha Deflecting device for cathode-ray tube
US4305055A (en) * 1980-06-24 1981-12-08 Rca Corporation Television display system incorporating a coma corrected deflection yoke
US4386331A (en) * 1980-06-06 1983-05-31 Denki Onkyo Co., Ltd. Deflection yoke
US6893309B2 (en) 2000-09-12 2005-05-17 Thomson Licensing S.A. Apparatus for correcting static electron beam landing error

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3271747D1 (en) * 1982-03-31 1986-07-24 Ibm Convergence unit for in-line colour cathode ray tube
JPS59196538A (ja) * 1983-04-20 1984-11-07 Matsushita Electric Ind Co Ltd 偏向ヨ−ク
NL8401444A (nl) * 1984-05-07 1985-12-02 Philips Nv Beeldbuis.
DE3665111D1 (en) * 1985-09-27 1989-09-21 Hitachi Ltd Convergence correcting device capable of coma correction for use in a cathode ray tube having in-line electron guns
JP2661024B2 (ja) * 1986-12-27 1997-10-08 ソニー株式会社 陰極線管

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2923844A (en) * 1956-02-04 1960-02-02 Gen Electric Cathode ray tube structure including convergence system
US3325675A (en) * 1964-08-05 1967-06-13 Paramount Pictures Corp Three in-line gun magnetic convergence system
US3840765A (en) * 1972-09-26 1974-10-08 Tokyo Shibaura Electric Co Shielding member between only the control and side beams in a color cathode ray tube

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2923844A (en) * 1956-02-04 1960-02-02 Gen Electric Cathode ray tube structure including convergence system
US3325675A (en) * 1964-08-05 1967-06-13 Paramount Pictures Corp Three in-line gun magnetic convergence system
US3840765A (en) * 1972-09-26 1974-10-08 Tokyo Shibaura Electric Co Shielding member between only the control and side beams in a color cathode ray tube

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4057747A (en) * 1974-10-14 1977-11-08 Tokyo Shibaura Electric Company, Ltd. In-line plural beam color cathode ray tube having deflection defocus correcting elements
US4257023A (en) * 1977-11-29 1981-03-17 Tokyo Shibaura Denki Kabushiki Kaisha Deflecting device for cathode-ray tube
US4237437A (en) * 1978-02-06 1980-12-02 U.S. Philips Corporation Deflection unit for color television display tubes
US4232283A (en) * 1979-03-27 1980-11-04 Rca Corporation Electron beam moving apparatus for a color cathode ray tube
US4386331A (en) * 1980-06-06 1983-05-31 Denki Onkyo Co., Ltd. Deflection yoke
US4305055A (en) * 1980-06-24 1981-12-08 Rca Corporation Television display system incorporating a coma corrected deflection yoke
US6893309B2 (en) 2000-09-12 2005-05-17 Thomson Licensing S.A. Apparatus for correcting static electron beam landing error

Also Published As

Publication number Publication date
FR2228293A1 (fr) 1974-11-29
JPS5522907B2 (fr) 1980-06-19
JPS50712A (fr) 1975-01-07
DE2408994B2 (de) 1979-08-16
FR2228293B1 (fr) 1977-09-23
DE2408994A1 (de) 1974-11-14
DE2408994C3 (de) 1980-05-14
GB1436925A (en) 1976-05-26
IT1009332B (it) 1976-12-10

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