US2597298A - Beam centering device for cathoderay tubes - Google Patents

Beam centering device for cathoderay tubes Download PDF

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Publication number
US2597298A
US2597298A US144688A US14468850A US2597298A US 2597298 A US2597298 A US 2597298A US 144688 A US144688 A US 144688A US 14468850 A US14468850 A US 14468850A US 2597298 A US2597298 A US 2597298A
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United States
Prior art keywords
magnets
annular
magnet
cathode ray
ray tube
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Expired - Lifetime
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US144688A
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English (en)
Inventor
Court Patrick Richard James
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Pye Electronic Products Ltd
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Pye Ltd
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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
    • H01J29/54—Arrangements for centring ray or beam

Definitions

  • the present invention relates to devices for icenteringthe electron beam on the screen of a cathode ray-tube a'nd is particularly applicable to the centering of the raster on the screen of :thecathode ray tube. of a television receiver.
  • Each magnet may comprise a single magnet or may'be assembled from a pair of part-annular magnets arranged substantially concentrically to form a complete annulus but with narrow gaps between the ends of the pair of magnets,'like poles" of each of the magnets of a pair lying adjacent one another, the two pairs of magnets being disposed side-by-side around the neck of the cathode ray tube and mounted for independent rotation around said neck and substantially concentrically with the axis thereof.
  • each annular magnet or pair of part-annular magnets
  • The'resultant magnetic field due to each annular magnet is very uniform at the centre or axis of the neck of the cathode ray tube where the electron beam passes, and by rotating either or both of the Y magnets which are arranged close together but nottouchingaround the tube neck, the strength and direction of the resultant magnetic field along-"the axis of the tube neck may be changed in accordance with the relative positions of the magnets.
  • the magnetic field at the axis of the cathode ray tube will actually be the vector sum of the two; separate fields.
  • the magnets maybe conveniently made. quite small, of only slightly larger internal diameter than theexternal diameter of the neck of the cathode ray tube, and each magnet is preferably thin and fiat in the axial direction of the assembly.
  • the magnets may be separated from one another by an intervening layer of nonmagnetic.
  • material n the'case Whe e ch ma t omp is s a pair of part-annular magnets, each part-am nula'r, magnet is preferably almost a complete semi-annulus, so that when a pair of magnets are arranged concentrically only narrow gaps existbetween adjacent ends of the magnets.
  • :maeriasj may be "carried oninsulating discs or yniembers whichmay be'cairistructed to rotate aroundthe'neckof the tube, and'the magnets of onepairmaybe 'separated from the magnets of the other pair by an interposed layer of -nonmagnetic material.
  • the two magnets may be arranged concentrically round the neck of a cathode ray tube, between the focus magnet or con and the, deflector coils. By simply rotating the two magnets with respect to each other and with respect to the tube, the electron beam may be. moved to any desired position, within the limits imposed by the strength of the magnet fields.
  • Fig. 1 shows aperspective view of one embodiment according to the invention.
  • Fig. 2 shows a view similar to Fig. 1 but with the elements of the centering device exploded.
  • Fig. 3 shows a section through the device .mounted on a cathode raytube.
  • Fig. 4 shows an end view of an alternative construction of magnet.
  • the centering device comprises two annular permanent magnets I, 2 magnetised across their diameters as more clearly indicated in Fig. 2. These magnets may be made of thin sheet metal and are mounted at the front of a focussing the centre of the assembly. Positioned between the focussing magnet 3 and the magnet l are three annular spacers of non-magnetic and preferably insulating sheet material 5, B and I; between the two magnets I and 2 is a further annulus of non-magnetic sheet material 8; and infrontof the magnet 2 is another annulus of non-magnetic sheet material 9. The whole assembly is held in position to the front of the focus magnet 3 by means of three clips [0 secured to the magnet 3 by screws 1 I.
  • the longitudinally extending limbs l0a of these clips are positioned one circle correspondingapproximately to the internal diameter of the magnets 1 and 2 so that "the latterare guidingly rotatable therearound.
  • the internal diameters of the spacers are smaller than the internal diameter of the magnets I and 2, recesses 12 being formed in the internal peripheries of the spacers to accommodate the clips I0, whereby rotation of the spacers is prevented.
  • the whole assembly is held against the focus magnet 3 by the outwardly turned ends b of the clips 10 bearing on the outer surface of the spacer 9.
  • the spacer 6 is of wavy or corrugated form so as to exert a slight axial pressure on the elements of the assembly and create friction between the magnets I and 2 and the adjacent spacers so that the magnets will remain in the adjusted position to which they are turned.
  • the magnets are provided with ears la, 2a extending beyond the external periphery of the insulating spacers.
  • the centering assembly By making the centering assembly narrow in the axial direction, it can be disposed in between the focus magnet and the deflector coils [4, as shown in Fig. 3.
  • Centering of the cathode ray beam is achieved by simply rotating the two annular magnets independently around the neck of the cathode ray tube.
  • each magnet may comprise a pair of flat part-annular magnets 20, 2
  • is almost a complete semi-annulus, so that if the magnets are secured concentrically on the supporting ring 22, the ends of the two magnets are spaced apart by narrow gaps.
  • lie adjacent to one another.
  • each ring 22 is made of a size to fit the neck of the cathode ray tube, two such rings each carrying pairs of part-annular magnets being disposed around the neck of the tube and arranged sideby-side between the focussing magnet and the deflector coils.
  • the two rings may be separated by a further ring 25 of non-magnetic material to prevent contact between the two sets of magnets. If desired, two further rings of non-magnetic material may be used to space the magnet rings from the deflector coils and from the focus magnet respectively.
  • , when concentrically secured on the supporting ring, are preferably slightly spaced from the internal periphery of the ring, so that the said internal periphery forms a bearing with the external surface of the neck of the cathode ray tube, around which the ring can be rotated.
  • the rings on which the magnets are mounted may be provided with projecting arms or lugs.
  • the - magnets may be mounted for rotation around the deflection coils. for example, adjacent the end thereof which lies adjacent the bulb of the oathode ray tube when the deflector coils are mounted on the tube neck.
  • the beam centering magnets adjacent the bulb of the tube, corner cutting of the beam (that is interception of the deflected beam by the corner of the tube between the neck and bulb portions) may be prevented or reduced.
  • the two magnets may rotate around a cylindrical member, which may be grooved, fitted around the deflector coil assembly adjacent one end thereof.
  • the pairs of magnets may be provided with windings, means being provided for varying the current flowing through the windings.
  • the raster will be normally displaced off-centre and towards one corner of the screen, and by separately energising the windings in opposition to the field produced by the permanent magnets, the position of the raster can be shifted towards the centre.
  • This modification provides a centering arrangement in which the control is effected electrically instead of mechanically.
  • a device for centering the electron beam of a cathode ray tube comprising two annular magnets each permanently mag'netised across its diameter means for supporting said two magnets side-by-side and coaxially surrounding the neck of the cathode ray tube, each magnet being independently rotatable around the common axis, a thin annular spacer of non-magnetic material positioned between said magnets, and resilient means urging said magnets axially towards one another with the spacer compressed therebetween.
  • a device for centering the electron beam of a cathode ray tube comprising two annular magnets each permanently magnetised across its diameter, each of said magnets being made from thin sheet magnetic material with the thickness of the sheet defining the axial length of a magnet, means for supporting said two magnets coaxialiy side-by-side and surrounding the neck of the cathode ray tube and with each magnet independently rotatable around the common axis, a thin annular spacer of non-magnetic material positioned between said magnets, resilient means urging said magnets axially towards one another with the spacer therebetween, and means for rotating each of said magnets independently about said common axis.
  • a device for centering the electron beam of a cathode ray tube comprising a support member having a central aperture through which the neck of a cathode ray tube is adapted to pass, two annular magnets each permanently magnetised across its diameter, a plurality of members extending longitudinally from one side of the support member, the outer surfaces of said members lying on a circle of a diameter corresponding to the internal diameters of the annular magnets and substantially coaxial with the aperture in the support member, said annular magnets being arranged side-by-side and surrounding said longitudinal members so as to be independently rotatable therearound, a thin annular spacer of non-magnetic material positioned between said annular magnets and having at least one notch on its inner periphery adapted to engage-- with one of said longitudinal members to prevent rotation of said spacer, and means for holding the two magnets in positions adjacent opposite faces of said spacer respectively.
  • a device as claimed in claim 3, comprising also two annular members of non-magnetic-material positioned respectively adjacent the-outer faces of said annular magnets, an annular corrugated member of resilient material positioned between the support member and the annular member nearest thereto, at least one notch in each of said annular members and the corrugated member engaging with one of the longitudinal members to prevent relative rotation therebetween, abutments carried from the free ends of the longitudinal members and bearing against the end of the outer annular member, said abutments being so spaced from the support member that the corrugated member will be slightly compressed and thereby urges the two annular magnets together with the spacer therebetween, and at least one ear projecting from the outer periphery of each of the annular magnets and beyond the external peripheries of the annular members.
  • a combined focussing and beam centering device for the cathode ray tube of a television receiver comprising a focussing device having a central aperture through which the neck of a cathode ray tube is adapted to pass, two annular magnets each permanently magnetised across its diameter, a plurality of members extending longitudinally from one side of the focussing device, the outer surfaces of said members lying on a circle of a diameter corresponding to the internal diameters of the annular magnets and substantially coaxial with the aperture in the focussing device, said annular magnets being arranged side-by-side and surrounding said longitudinal members so as to be independently rotatable therearound, a thin annular spacer of non-magnetic material positioned between said annular magnets and having at least one notch on its inner periphery adapted to engage with one of said members to prevent rotation of said spacer, two annular members of non-magnetic material positioned respectively adjacent the outer faces of said annular magnets an annular corrugated member of resilient material positioned between the
  • a device for centering the electron beam of a cathode ray tube comprising two annular magnets each permanently magnetised across its diameter, means for supporting said two magnets side-by-side and coaxially surrounding the neck of the cathode ray tube, and with each magnet independently rotatable around the common axis, a thin annular spacer of non-magnetic material extending radially between said magnets, and at least one ear connected to and extending outwardly from each of said magnets.

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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)
US144688A 1949-02-18 1950-02-17 Beam centering device for cathoderay tubes Expired - Lifetime US2597298A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4446/49A GB670021A (en) 1949-02-18 1949-02-18 Improvements in beam centering devices for cathode ray tubes

Publications (1)

Publication Number Publication Date
US2597298A true US2597298A (en) 1952-05-20

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US (1) US2597298A (de)
DE (1) DE973714C (de)
GB (1) GB670021A (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1041170B (de) * 1952-10-23 1958-10-16 Cossor Ltd A C Anordnung zum Zentrieren des Leuchtflecks auf den Leuchtschirm einer Kathodenstrahlroehre
US2860329A (en) * 1955-01-18 1958-11-11 Sol L Reiches Centering device for cathode ray tube and tv receiver using same
US2907908A (en) * 1955-09-01 1959-10-06 Philco Corp Apparatus for preventing distortion in plural beam cathode ray tubes
US2922908A (en) * 1955-08-31 1960-01-26 Westinghouse Electric Corp Retaining device
US3356879A (en) * 1963-08-14 1967-12-05 Zenith Radio Corp Beam positioning device for varying the effective origin of cathode-ray tube electron beam
US3808570A (en) * 1972-03-20 1974-04-30 Rca Corp Static convergence device for electron beams
US5399933A (en) * 1993-05-20 1995-03-21 Chunghwa Picture Tubes, Ltd. Magnetic beam adjusting rings with different thickness

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE522315A (de) * 1952-08-26
DE1186561B (de) * 1960-07-06 1965-02-04 Magnetfab Bonn Gmbh Ringfoermiger Korrekturmagnet fuer Kathodenstrahlroehren und Verfahren zur Herstellung des Korrekturmagneten
US4549155A (en) * 1982-09-20 1985-10-22 The United States Of America As Represented By The United States Department Of Energy Permanent magnet multipole with adjustable strength

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB464637A (en) * 1934-10-19 1937-04-21 Fernseh Ag Improvements in or relating to magnetic deflecting means for cathode-ray tubes
US2102421A (en) * 1934-07-12 1937-12-14 Gen Electric Cathode ray oscillograph
US2188579A (en) * 1933-05-27 1940-01-30 Loewe Radio Inc Cathode ray tube, more particularly for television purposes
US2195470A (en) * 1936-03-03 1940-04-02 Telefunken Gmbh Cathode ray tube deflection system
US2224933A (en) * 1934-02-09 1940-12-17 Loewe Radio Inc Magnetic distortion correcting means for cathode ray tubes
US2455977A (en) * 1946-12-31 1948-12-14 Philco Corp Magnetic lens for correcting scanning defects
US2456474A (en) * 1946-07-02 1948-12-14 Gen Electric Electric discharge device
US2498354A (en) * 1946-12-03 1950-02-21 Philco Corp Magnetic lens system
US2513929A (en) * 1948-05-21 1950-07-04 Gen Electric Beam centering device for cathode-ray tubes
US2525919A (en) * 1948-07-01 1950-10-17 Hazeltine Research Inc Centering arrangement for cathode-ray tubes
US2544875A (en) * 1950-03-02 1951-03-13 Pye Ltd Combination centering, focusing, and deflecting device for beam of cathode-ray tubes
US2544898A (en) * 1949-12-31 1951-03-13 Guardian Electric Mfg Co Centering device for beams of cathode-ray tubes

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR747139A (fr) * 1931-11-10 1933-06-12 Appareils de déviation de courants électroniques dans les tubes à rayons cathodiques
AT135287B (de) * 1931-12-12 1933-11-10 Telefunken Gmbh Einrichtung zum Synchronisieren von Kathodenstrahl-Bildschreibern.
DE681755C (de) * 1934-02-09 1939-09-30 Loewe Opta Gmbh Anordnung zur Kompensation aeusserer magnetischer Stoerfelder bei Kathodenstrahlroehren
DE970708C (de) * 1934-10-19 1958-10-16 Fernseh Gmbh Anordnung zur Beeinflussung von Elektronenstrahlen in Kathodenstrahlroehren mit einer Strahlbegrenzungsblende
DE701422C (de) * 1936-03-03 1941-01-16 Telefunken Gmbh Einrichtung zur Kompensation der von der Gleichstromkomponente eines unsymmetrischen Saegezahnstromes erzeugten Ablenkung
DE688644C (de) * 1937-05-29 1940-02-27 Aeg r koaxialen Teillinsen besteht
FR79502E (fr) * 1957-05-30 1962-12-14 Armstrong Patents Co Ltd Perfectionnements aux systèmes de suspension de véhicules

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2188579A (en) * 1933-05-27 1940-01-30 Loewe Radio Inc Cathode ray tube, more particularly for television purposes
US2224933A (en) * 1934-02-09 1940-12-17 Loewe Radio Inc Magnetic distortion correcting means for cathode ray tubes
US2102421A (en) * 1934-07-12 1937-12-14 Gen Electric Cathode ray oscillograph
GB464637A (en) * 1934-10-19 1937-04-21 Fernseh Ag Improvements in or relating to magnetic deflecting means for cathode-ray tubes
US2195470A (en) * 1936-03-03 1940-04-02 Telefunken Gmbh Cathode ray tube deflection system
US2456474A (en) * 1946-07-02 1948-12-14 Gen Electric Electric discharge device
US2498354A (en) * 1946-12-03 1950-02-21 Philco Corp Magnetic lens system
US2455977A (en) * 1946-12-31 1948-12-14 Philco Corp Magnetic lens for correcting scanning defects
US2513929A (en) * 1948-05-21 1950-07-04 Gen Electric Beam centering device for cathode-ray tubes
US2525919A (en) * 1948-07-01 1950-10-17 Hazeltine Research Inc Centering arrangement for cathode-ray tubes
US2544898A (en) * 1949-12-31 1951-03-13 Guardian Electric Mfg Co Centering device for beams of cathode-ray tubes
US2544875A (en) * 1950-03-02 1951-03-13 Pye Ltd Combination centering, focusing, and deflecting device for beam of cathode-ray tubes

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1041170B (de) * 1952-10-23 1958-10-16 Cossor Ltd A C Anordnung zum Zentrieren des Leuchtflecks auf den Leuchtschirm einer Kathodenstrahlroehre
US2860329A (en) * 1955-01-18 1958-11-11 Sol L Reiches Centering device for cathode ray tube and tv receiver using same
US2922908A (en) * 1955-08-31 1960-01-26 Westinghouse Electric Corp Retaining device
US2907908A (en) * 1955-09-01 1959-10-06 Philco Corp Apparatus for preventing distortion in plural beam cathode ray tubes
US3356879A (en) * 1963-08-14 1967-12-05 Zenith Radio Corp Beam positioning device for varying the effective origin of cathode-ray tube electron beam
US3808570A (en) * 1972-03-20 1974-04-30 Rca Corp Static convergence device for electron beams
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
DE973714C (de) 1960-05-19
GB670021A (en) 1952-04-09

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