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US2859365A - Electron beam controlling apparatus - Google Patents

Electron beam controlling apparatus Download PDF

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Publication number
US2859365A
US2859365A US455996A US45599654A US2859365A US 2859365 A US2859365 A US 2859365A US 455996 A US455996 A US 455996A US 45599654 A US45599654 A US 45599654A US 2859365 A US2859365 A US 2859365A
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US
United States
Prior art keywords
magnetic
screen
tube
color
magnets
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
Application number
US455996A
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English (en)
Inventor
Albert M Morrell
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.)
RCA Corp
Original Assignee
RCA Corp
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
Priority to BE541271D priority Critical patent/BE541271A/xx
Application filed by RCA Corp filed Critical RCA Corp
Priority to US455996A priority patent/US2859365A/en
Priority to US473809A priority patent/US2816244A/en
Priority to US473865A priority patent/US2943218A/en
Priority to GB23498/55A priority patent/GB801487A/en
Priority to FR1140367D priority patent/FR1140367A/fr
Priority to DER17426A priority patent/DE1041075B/de
Application granted granted Critical
Publication of US2859365A publication Critical patent/US2859365A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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
    • H01J29/003—Arrangements for eliminating unwanted electromagnetic effects, e.g. demagnetisation arrangements, shielding coils
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/0007—Elimination of unwanted or stray electromagnetic effects
    • H01J2229/003—Preventing or cancelling fields entering the enclosure

Definitions

  • This invention relates to new and improved apparatus for use in controlling electrons in cathode ray tubes of the type employed as color television image reproducing devices. Specifically, the invention relates to such apparatus which is adapted for use in conjunction with cathode ray tubes having a plane of dellection at which electrons are subjected to a scanning movement in their travel toward a screen unit of the type comprising a socalled mosaic screen and one or more adjacent grills or .masks through which electrons pass in diiferent angular directions to preselected elemental areas of the mosaic.
  • the particular screen area which is illuminated at any given instant in a cathode ray tube of the type in question is a function of the precise angle at which the electron Ibeam approaches the color screen.
  • color dilution which is encountered incolor kinescopes is that which results from misalignment of the shadow mask or grill about its longitudinal axis with respect to the phosphor screen, this form of color dilution being termed tangential or rotational color dilution.
  • Still another source of diculty in the operation of color kinescopes of the type under consideration is that which is brought about by stray magnetic elds such, for example, as the earths magnetic i'ield.
  • the present invention provides means for subjecting the electron beams, in the space between the tubes shadow mask and target screen to substantially constant direct current magnetic elds of such intensity, polarity and orientation as to direct said electrons to their normal or intended points of impact on the screen, regardless of the section of the screen in which the beams may be operating.
  • such direct current, magnetic eld producing means may comprise la plurality of permanent magnets disposed around the screen unit of the cathode ray tube, each of the magnets being in association with magnetic pole forming means and being provided with a magnetic shunt piece, the permanent magnet and its shunt being mounted for relative movement in such manner that the strength and direction of the magnetic elds produced by the magnets may be suitably adjusted.
  • a plurality of electro-magnetic coils disposed around the screen region of the cathode ray tube, with separate means associated with each of the coils for applying direct current thereto in a manner which is adjustable as to field strength and direction.
  • the coils are so oriented with respect to pole forming means surrounding the screen unit that the active flux produced by the coils is generally parallel to the longitudinal axis of the tube.
  • the magnets whether of the electromagnetic or permanent magnetic type, and their pole pieces, are oriented to produce axial lields.
  • Such adjustable axial fields may serve to correct for either rotational misalignment of the parts of the tube or to neutralize undesired stray fields which are axial of the tube.
  • Fig. l is a side elevational view, partially in section
  • Fig. 2 is a diagrammatic illustration of a cathode ray tube oriented with respect to certain axes to be described;
  • Y""Figf3. is Va fragmentary vfront view, greatly enlarged, of the screen of the tube of Fig. 1;
  • FIG. 4 A, vFig'. 4'is aA front view of the apparatus of Fig. 1; FigQfS is an enlarged detail view of a portion of the apparatus of Figures l and 4;
  • Fig. 6 is a sectional view taken along line 6 6 of Figure 5;
  • Fig. 7 is a sectional View, with ⁇ certain parts omitted, taken along line 7-7 of Figure 6;
  • rfFig. 8 is an isometric view of another form of the invention.
  • the color kinescope lfshown therein comprises an evacuated envelope having'a cylindrical neck portion 12 of glass, for example, which terminates in a flared con-e portion 14 whose larger end is closed by a glass face plate 16 through whichY is visible the phosphor screen 18 of the target ⁇ structure of the tube which further includes a shadow mask or aperture mask electrode 20.
  • the tube as described thus far may be of the type disclosed in the above-cited Law article in which the phosphor screen 18 is of the well-known dot screenV variety.
  • the phosphor screen is deposited directly upon the rear surface of the face plate 16 and the mask 20is curvedl concentrically with the curvature of the face plate.
  • the screen 18 is provided on its surface with a multiplicity of groups of red, blue and green phosphor dots, the dots of each group being arranged at the apices of an equilateral triangle.
  • the mask element 20 of the screen unit comprises a thin metal plate containing a multiplicity of apertures arranged in the same triangular pattern as the trios of phosphor dots such that there is one mask aperture for each tro of phosphor dots.
  • the aperture mask 20 isgsupported in spaced relationship with respect to the screen 18 by suitable means (not shown).
  • the cylindrical neck portion 12 of the kinescope 10 houses three electron guns 24, 26 and 28, each of which produces an electron beam intended for bombardment of a particular screen color.
  • the guns 24, 26 and 28 may. be arranged at the apices of an equilateral triangle as shown in the Law article or in any other suitable manner such, for example, as an in-line arrangement.
  • the .electron beams produced by the guns are indicated diagrammatically by the dotted lines 30, 32 and 34 and are focused in a conventional manner by suitable means indicated as an electromagnetic focus coil 36 ⁇ energized by currents from a source 38, whereby to provide fine spots at the target screen.
  • the electron beams are subjected to the action of substantially perpendicular magnetic fields for the scanning, in horizontal and vertical directions, of a conventional rectangular raster at the screen unit.
  • Such scanning llelds are produced by means of a dellection yoke 40 which may comprise a pair of normally arranged deflection windings disposed about the neck of the kinescope and energized by suitable Vsawtooth c-urrents of television line and lield frequenciesfrom the dellection circuits 42.
  • the plane of deflection for thethree beams 30, 32v and 34 extends transversely through the dellection yoke 40.
  • Fig. 2 illustrates, in simplied form, the kinescope oriented about its several axes X, ⁇ Y and Z. It will be seen from Fig. 2 that the Zaxis coincides with the longitudinal axis of the tube,"'while the X and Yaxes are normal to each other and to the Z-axis.
  • Va primary object of the present invention is that of eliminating the vmask and diverge therefrom so that the red beam 3l) strikes the red-designated phosphor R and the' other beams 2 and 34 strike the green and bluedesignated phosphors G and B, respectively, which phosphor dots are arranged, as explained, at the apices of an equilateral triangle.
  • Va primary object of the present invention is that of eliminating the vmask and diverge therefrom so that the red beam 3l) strikes the red-designated phosphor R and the' other beams 2 and 34 strike the green and bluedesignated phosphors G and B, respectively, which phosphor dots are arranged, as explained, at the apices of an equilateral triangle.
  • the tangential color dilution is manifest at peripheral regions of the screen such that the red beam spots are not centered exactly on the red phosphor dots.V Rather, the red beam spots are tangent to or overlap and, hence, illuminate peripheral portionsof the adjacent blue and green phosphor dots, thus diluting the red light and preventing it from appearing with its proper degree of saturation.
  • the present in- ⁇ vention eliminates or, at least, substantially minimizes such color dilution through the agency of means for subjecting the several electron beams to the actionof substantially constant (i. e., D.
  • Figure l illustratesmeans, in accordance with a specic form of the invention, for providing the requisite axial magnetic eld, such means comprising a pluralitysof permanent magnets 50 disposed around the screen lunit of the tube 10,as illustrated in Figure 4. Interposed -between'the magnets 50 and the cathode ray tube are some of the iron rings 52 and 54 which serve as magf netic pole forming means.
  • the pole rings 52 and 54 are held in spaced relationship by means of spacers 5640i brass or other non-magnetic material, the spacers being ⁇ riveted or otherwise secured to the rings.
  • the rings are split and their loose ends are provided with brackets 58 of -brass or other' non-magnetic material.
  • Abrass bolt 60 is passed through holes in the brackets 58 for securing the assembly.
  • the rings are not mounted directly on the tube 10 but are, rather, separated therefrom by a cylinder 62 of plastic material or the like.
  • the cylinder 62 may, for example, form a part of the conventional mask usually associated with television receiver kinescopes. While eight of the permanent magnets 50 are shown in Figure 4, that is, two for each corner of the raster 64 scanned by the tube, it will be understood that fewer or-more magnets may be employed, depending upon the extent of correction control desired.
  • the permanent magnet 50 is a bar magnet having north and south poles designated N and S and is held by -a clamp 66 formed of suitablenonmagnetic spring material such as Phosphor bronze.
  • a rivet 68 passed through an aperture 70 in the bottom of the clamp 66'is secured to one, end of a threadcdbolt 72.
  • the bolt 72 passes'through a shunt piece 74 of soft iron or other magnetic material which is supported by a block 76 of Lucite or other plastic composition, as indicated in Figure 7.
  • the shunt piece 74 is provided vat each end with a detent or struck-down portion 78, the detent being held in depressions 80 in the top surface of the block 76.
  • a coil compression spring 82 which may be conical, as shown, surrounds the bolt 72 and bears against a continuous groove 84 in the under-surface of the block 76. The end of the spring 82 remote from the block, bears against a Washer 86 which is held ou the bolt by means of a nut 88.
  • the block 76 is supported, with respect to the soft iron rings 52 and 54, by means of soft iron brackets 90 and 92.
  • the brackets 90 and 92 are secured, respectively, to the rings 52 and 54 by means of rivets 94 and the block 76 is secured to vupwardly-extending portions 96 and 9S of the brackets by screws 100.
  • the magnet 50 carried by the clamp 66 may be rotated about the axis of the bolt 72.
  • the north and south poles of the magnet will be spaced ⁇ a very short distance from the upwardly-extending portions of the brackets 96 and 98, so that the path of the magnetic ux produced by the magnet 50 may be traced through the apparatus as follows:
  • ux will pass through the member 98 and its lower portion 92 to the pole ring 54.
  • the pole ring 54 serves to spread the llux over an appreciable angle of the tube, and the ux passes from the ring 54 to the ring 52, from which it travels through the bracket 90 and its upwardly-extending portion 96 to the south pole of the magnet.
  • the pole forming rings 52 and 54 serve, in addition to their 'function of enlarging the sector of activity of each of the magnets 50, to render the active magnetic eld in the region of the screen unit of the tube more uniformly axial with respect to the tube.
  • each of the magnets 50 may be rotated about its bolt 72 so that it is perpendicular to its shunt piece 74. In this position t the magnetic elds produced will be maximum. Normally, if it is found that color dilution in ⁇ a particular section of the raster is increased rather than decreased with the magnets adjacent that section polarized in a given direction, that fact indicates that the magnetic eld operating upon the raster there is of the wrong polarity. The magnet in question may then be rotated through 180 until the proper magnitude of magnetic eld of the required polarization is provided.
  • the permanent magnets nearest that section may be eectively immobilized by rotating them until they are parallel to their magnetic shunt pieces 74.
  • the rings may be continuous, if desired.
  • speciiic magnetic materials have been set forth by way of example for the rings and their extensions and 92, it is to be understood that other materials offering the necessary magnetic properties may be substituted.
  • substitutions of materials may ⁇ also be made for the spacers S6, bracket 66 Iand the other non-magnetic elements of the apparatus.
  • FIG 8 is illustrative of a second form of the invention; namely, that employing electromagnetic means in place of the permanent magnets heretofore described.
  • an electromagnetic coil 104 which is generally of cylindrical form is mounted on the pole forming rings 52 and 54 so that the rings lie adjacent the opposite magnetic poles of the coil.
  • the coil 104 is supplied with direct current energy from a variable source illustrated, by way of example, as Icomprising a rheostat 106 across which is connected a battery 108 whose terminals may be connected in either of two directions to the ends 110 and 112 of the rheostat.
  • a reversing switch 114 Such reversible connections are made through the agency of a reversing switch 114.
  • each of the coils being supplied with reversible and variable direct current from a separate source.
  • the electromagnetic assembly is mounted around the screen region of a cathode ray tube such as the tube 10 of Figure l and is effective in correcting color purity in the following manner. Assuming that there exists a condition of color dilutionof the tangential type, as by reason of rotational misalignment of the tube elements or by reason of stray magnetic fields having axial components, each of the coils 104 is connected to its energy source.
  • the reversing switches should be moved to their opposite positions and the rheostats adjusted to provide the proper magnitude of current through the coils for eiecting rotational movement of the beams with respect to the phosphor screen.
  • the pole rings 52 and 54 By virtue of the pole rings 52 and 54, the magnetic eld of each of the coils 104 is spread over a substantially greater angle than that which would be aiected in the absence of the rings, so that the number of coils required is thereby substantially reduced.
  • the rings 52 and 54 serve to insure that the magnetic tields of the coils are substantially parallel to the longitudinal Vaxis of the cathode ray tube about which they are located.
  • the present invention provides means comprising a plurality of magnets disposed around the screen unit of a tri-color kinescope, which magnets are adapted to be active in the marginal regions of the raster scanned on the screen and for the purpose of substantially eliminating tangential color dilution error.
  • the pole forming means provided by the invention served to improve the shapes of the magnetic elds and to extend the activity of each magnet over a wider range than is otherwise possible.
  • adjustability of the strength of the magnetic elds is aorded through the agency Iof the shunt pieces, while the strength of the electromagnetic elds is adjustable in the manner shown.
  • the Combinationzwith envisagerV imageTreproducing cathodez-rayutube having -aa longitudinal axismandrfa plane eindeectionat which electrons are subjectedto a scanningldeflection ill-their, transit in 4angularly related paths topa mosaic screen k.of thel type comprising areas of respectivelyxdiierent ycolor,characteristics,of la plurality of permanent magnets farranged around ⁇ such paths and -located in ⁇ the Vicinity'ofg-said screenaandV magnetic vpole-forming means-,located-between ,-said ⁇ magnets and said tube for causing saidmagnets toaproduce ,magnetic elds whose linesA of ux are generally-parallel lto said longitudinal axis.
  • An ,adjunctfor a color imagefreproducing cathode ray tube of.the type including a plane of deflection at whichelectrons-are subjected .to a scanning deflection in ther..transit,toward a ,mosaicrscreen ⁇ made up-of a pluralityrof areas of respectively ,dierent color characteristics,-said adjunct comprising: a ⁇ plurality .of magnets, means for supporting .said ⁇ magnets inlring-like array such that said .magnets-may be,disposed.-aroundand ladjacent -to such screenvand magnetic .pole-forming means within said ring-like'array forcausngsaid magnets to produce magnetic ields whoselines Vof uX are in the -axial directionfof such tube. ⁇

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
US455996A 1954-09-14 1954-09-14 Electron beam controlling apparatus Expired - Lifetime US2859365A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
BE541271D BE541271A (xx) 1954-09-14
US455996A US2859365A (en) 1954-09-14 1954-09-14 Electron beam controlling apparatus
US473809A US2816244A (en) 1954-09-14 1954-12-08 Electron beam controlling apparatus
US473865A US2943218A (en) 1954-09-14 1954-12-08 Electron beam controlling apparatus
GB23498/55A GB801487A (en) 1954-09-14 1955-08-15 Arrangement for connecting tangential and/or radial distortions in a cathode ray beam
FR1140367D FR1140367A (fr) 1954-09-14 1955-09-01 Appareil pour la commande des faisceaux électroniques
DER17426A DE1041075B (de) 1954-09-14 1955-09-14 Vorrichtung zur Korrektur der Richtungen eines Elektronenstrahles in einer Farbfernsehroehre

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US455996A US2859365A (en) 1954-09-14 1954-09-14 Electron beam controlling apparatus

Publications (1)

Publication Number Publication Date
US2859365A true US2859365A (en) 1958-11-04

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Family Applications (1)

Application Number Title Priority Date Filing Date
US455996A Expired - Lifetime US2859365A (en) 1954-09-14 1954-09-14 Electron beam controlling apparatus

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US (1) US2859365A (xx)
BE (1) BE541271A (xx)
DE (1) DE1041075B (xx)
FR (1) FR1140367A (xx)
GB (1) GB801487A (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939979A (en) * 1957-04-26 1960-06-07 Sol L Reiches Color pure cathode ray tube display mechanism
US2982200A (en) * 1958-06-06 1961-05-02 Swing Spout Measure Co Can crushing machine
US20040095054A1 (en) * 2001-03-16 2004-05-20 Jong-Eon Choi Color cathode ray tube

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL295045A (xx) * 1962-07-09
DE1270077B (de) * 1966-11-10 1968-06-12 Werk Fernsehelektronik Veb Verfahren zur Vermeidung von Farbfehlern bei Farbfernsehbildroehren

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2258643A (en) * 1938-04-25 1941-10-14 Philips Nv Distortion correction for cathode ray tubes
US2459732A (en) * 1946-03-26 1949-01-18 Philco Corp Electrical system
US2513221A (en) * 1948-07-01 1950-06-27 Rca Corp Register correction for television
US2518200A (en) * 1947-10-03 1950-08-08 Rca Corp Television system
US2529485A (en) * 1945-10-09 1950-11-14 Thornton W Chew Color television
US2541446A (en) * 1949-01-04 1951-02-13 Barnet S Trott Image distortion corrector for cathode-ray tubes
US2663757A (en) * 1950-03-06 1953-12-22 Gen Teleradio Inc Television apparatus

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE727477C (de) * 1938-04-25 1942-11-04 Philips Patentverwaltung Einrichtung zur Beseitigung der Verzerrung der bei einer Kathodenstrahlroehre vom Kathodenstrahl beschriebenen Figur

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2258643A (en) * 1938-04-25 1941-10-14 Philips Nv Distortion correction for cathode ray tubes
US2529485A (en) * 1945-10-09 1950-11-14 Thornton W Chew Color television
US2459732A (en) * 1946-03-26 1949-01-18 Philco Corp Electrical system
US2518200A (en) * 1947-10-03 1950-08-08 Rca Corp Television system
US2513221A (en) * 1948-07-01 1950-06-27 Rca Corp Register correction for television
US2541446A (en) * 1949-01-04 1951-02-13 Barnet S Trott Image distortion corrector for cathode-ray tubes
US2663757A (en) * 1950-03-06 1953-12-22 Gen Teleradio Inc Television apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939979A (en) * 1957-04-26 1960-06-07 Sol L Reiches Color pure cathode ray tube display mechanism
US2982200A (en) * 1958-06-06 1961-05-02 Swing Spout Measure Co Can crushing machine
US20040095054A1 (en) * 2001-03-16 2004-05-20 Jong-Eon Choi Color cathode ray tube

Also Published As

Publication number Publication date
FR1140367A (fr) 1957-07-19
GB801487A (en) 1958-09-17
BE541271A (xx)
DE1041075B (de) 1958-10-16

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