US2917646A - Deflecting coil system for cathode ray tubes - Google Patents

Deflecting coil system for cathode ray tubes Download PDF

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Publication number
US2917646A
US2917646A US627785A US62778556A US2917646A US 2917646 A US2917646 A US 2917646A US 627785 A US627785 A US 627785A US 62778556 A US62778556 A US 62778556A US 2917646 A US2917646 A US 2917646A
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layers
winding
wound
turns
layer
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US627785A
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English (en)
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Janssen Peter Johanne Hubertus
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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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
    • H01J29/72—Arrangements for deflecting ray or beam along one straight line or along two perpendicular straight lines
    • H01J29/76—Deflecting by magnetic fields only
    • H01J29/766—Deflecting by magnetic fields only using a combination of saddle coils and toroidal windings

Definitions

  • This invention relates to deflection coil systems for cathode-ray tubes having a ferromagnetic annular core the cross-section of which is embraced by the coils for the slow or vertical deflection, all the layers of these coils being wound in the same Vhelical direction.
  • Such a coil system is known from U.S. Patent 2,239,865.
  • this particular manner of winding prevents the formation of resonant circuits by each pair of successive winding layers together with the capacitance between the adjacent wires, which circuits are excited by the sawtooth line deflection field and give rise to spurious oscillations causing very undesirable distortions of the frame deflecting field, particularly if the coils are of the high-impedance type.
  • each of the frame deflection coils is at least approximately rectangular, that is to say, all the layers of the toroidal coilcomprise the same number of turns. It is an object .of the present invention to provide a deflection coil system containing frame or vertical deilection coils of a different shape, which is suitable for wide-angle deflection, the said advantage of freedom from spurious oscillations being retained. According' to the invention, this is ensured in that the layers are wound with decreasing overall width in an axial direction so that a cross-section through half the coil exhibits a generally trapezoi-dal shape, with' each layer being divided in at least two parts which succeed one another in the direction of winding. Further, each layer starts at a point situated within the axial boundary of the outermost winding layer and, after a part which begins at this point has been wound and the winding wire is returned, a preceding part is wound up to the said point.
  • Fig. 1 shows a deflecting system of a known kind
  • FIGs. 2 and 3 illustrate diagrammatically two known manners of winding which may be used in the system shown in Fig. 1,
  • Fig. 4 illustrates the operation of another coil system
  • FIGs. 5 and 6 illustrate diagrammatically two embodiments of the invention, while Fig. 7 shows still a further embodiment of the invention, and
  • Fig. 8 is an axial cross-sectional view of o-ne half of a coil system of the invention mounted in operating position.
  • the known deflection coil system shown in Fig. l comprises two coils 1 for the frame deflection (vertical deflection) and two coils 3 for the line deflections (horizontal), the coils being wound as toroids on an annular, in the present case square, soft-ferromagnetic core 5 so that the windings embrace the sectional are of the core (so-called toroidal windings).
  • the core 5 surrounds the neck of a cathode ray tube 7 in the usual manner.
  • the line deflection coils 3 periodically produce a sawtooth ICC magnetic deflecting field in the tube which is indicated in Fig. 1 byV a number of lines of force 9.
  • Fig. 1 shows that the field 9 traverses the coils l and can induce pulse-shaped voltages in these coils. These voltages are in opposition in the two halves of each of the coils 1 situated on both sides of the vertical median or center symmetry line 11 and compensate each other to a certain extent.
  • Fig. 2 is a vertical axial cross-sectional view of part of the upper half of one of the coils 1 and shows the instantaneous distribution of the induced pulse voltages over the turns of the first two layers of the coil by means of figures placed above or below the turns indicating, on an arbitrary scale, the pulse voltage on each winding at the spot where the winding is intersected.
  • the numeral 1 placed above or below a turn of the coil indicates that there is induced therein due to flux from the horizontal coil system a voltage having an arbitrary magnitude of l and a certain polarity.
  • the numeral 4 indicates a voltage induced in the turn with a magnitude four times that represented by the numeral l and of the same polarity.
  • the numeral 3, for example, denotes an induced voltage three times greater than that represented by the numeral 1 but of the opposite polarity.
  • the starting turn of each layer is labelled 0, and the symmetry and winding sense determines the other numerals.
  • the horizontal dash-dot line represents the center line of the coil and the bottom half is identical to the top half shown.
  • Deflection coils of rectangular axial cross-section are found to produce a field which is not entirely uniform and this is a serious disadvantage particularly in the case of deflection through a large angle (for example
  • saddle coils of substantially trapezoidal cross-section In order to ensure this improved uniformity in toroidal coils, according to the invention these coils can be wound with decreasing axial width of the layers, as is shown in Fig. 4.
  • these parts are separated by a broken line 13), starting from a point (near the broken line 13) of the layer to be wound which is situated within the axial boundary (the broken line 13) of the outermost winding layer and, after the part starting from this point has been wound and the winding wire has been returned, winding the preceding part up to the said point.
  • the line dividing the two parts of the winding and the starting point preferably are situated midway between the ends of the layer, that is to say on the line 11 as shown in Fig. 6, since the winding process can thus be simplified.
  • the part first wound of each layer (with the exception of the two uppermost layers) is followed in the direction of winding and is preceded in the opposite direction by parts which are wound only after a part of the following and/ or preceding layer has been provided.
  • the eight turns of the second layer which are wound first are followed in the second layer by two turns which are wound after the provision of a part of the third layer and are preceded by two turns (immediately to the left of the broken line 13) wound after the provision of a few turns of the first layer and also by two turns wound after the provision of a part of the third layer (and of the first layer).
  • the starting point lies within the axial boundary of the outermost layer i.e., at a turn lying underneath the outermost layer, and all the turns situated directly above one another are at the same voltage.
  • the symmetry relative to the center line 11 is maintained, in that the interconnected turns of the same layer of the preceding and subsequent wound portions are located the same distance from the symmetry line 11.
  • Fig. 8 shows a practical embodiment of a deecting system in accordance with the invention.
  • r[he ferromagnetic core 15 is circular and the (uppermost) frame deflector toroidal coil 17 is wound on a correspondingly curved insulating coil former 19, the line deector coil 21 being designed as a saddle coil.
  • the coil 17 may comprise 10 layers having in all 2500 turns. Since the layers are shorter on the inside of the annular core than on the outside, the turns are not arranged as uniformly as is shown in Fig. 5, so that, for example, at some points on the outside the turns of a layer are interposed between the turns of the next subsequent layer. However, it has been found in practice that the desired effect is fully achieved.
  • a deflection coil system comprising a magnetic core, and a toroidal winding comprised of a plurality of layers of turns on said core, said toroidal winding having a generally trapezoidal-shaped half cross-section, the winding starting point of the inner layers being at a turn lying underneath the outermost layer and said layers being wound in the same direction such that adjacent turns in adjacent layers are substantially at the same induced potential when the system is excited.
  • a deection coil system comprising a magnetic core
  • a toroidal winding comprised of a plurality of layers of turns on said core, said toroidal winding having a generally trapezoidal-shaped half cross-section, the inner said layers commencing at a point intermediate their ends and all the layers being wound in the same direction, whereby substantially no induced potential difference exists between adjacent turns in adjacent layers when the system is excited.
  • a deection coil system comprising an annular magnetic core, and a toroidal winding comprised of a plurality of layers of turns on said core, said toroidal winding having a generally trapezoidal-shaped half cross-section, the inner said layers commencing at a turn intermediate their ends lying underneath the outermost layer and all the layers being wound in the same direction, so that the initial part of the inner layers is wound after a terminal part, and elongated conductor means interconnecting the initial and terminal parts of the thus-wound inner layers, whereby substantialy no induced potential difference exists between adjacent turns in adjacent layers when the winding system is excited.
  • a defiection coil system for producing the frame scan in a cathode-ray tube comprising a magnetic core, and a toroidal winding comprised of a plurality of layers of turns on said core, said toroidal winding having a generally trapezoidal-shaped half cross-section, each of said layers being wound in the same direction and the inner layers comprising adjacent, discontinuous, wound portions with the wound portion at the end remote from the winding starting point being wound before the preceding layer portion is wound, whereby substantially no induced potential difference exists between adjacent turns in adjacent layers when the system is excited.
  • each layer commences at its center.
  • a deection coil system comprising a magnetic core, and a toroidal winding comprised of a plurality of layers of turns on said core, said toroidal winding having a generally trapezoidal-shaped half cross-section and each of said layers being wound in the saine direction, and plural conductor means interconnecting the adjacent inner layers, each of said inner layers commencing as a winding at a turn located underneath the outermost layer.

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  • Details Of Television Scanning (AREA)
  • Coils Or Transformers For Communication (AREA)
US627785A 1956-01-05 1956-12-12 Deflecting coil system for cathode ray tubes Expired - Lifetime US2917646A (en)

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NL349006X 1956-01-05

Publications (1)

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US2917646A true US2917646A (en) 1959-12-15

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US627785A Expired - Lifetime US2917646A (en) 1956-01-05 1956-12-12 Deflecting coil system for cathode ray tubes

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US (1) US2917646A (en, 2012)
BE (1) BE553914A (en, 2012)
CH (1) CH349006A (en, 2012)
DE (1) DE1053677B (en, 2012)
FR (1) FR1185310A (en, 2012)
GB (1) GB840807A (en, 2012)
NL (1) NL102926C (en, 2012)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3089761A (en) * 1958-05-16 1963-05-14 Socony Mobil Oil Co Inc Fuel oil composition
US3152291A (en) * 1960-03-10 1964-10-06 Telefunken Ag Magnetic deflection yoke
US3671896A (en) * 1971-05-21 1972-06-20 Sylvania Electric Prod Deflection system for triad-beam cathode ray tube

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4511871A (en) * 1983-07-18 1985-04-16 Rca Corporation Modified deflection yoke coils having shootback windings

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB516743A (en) * 1937-07-06 1940-01-10 Telefunken Gmbh Improvements in or relating to electromagnetic deflecting systems for cathode ray tubes
US2383308A (en) * 1941-05-08 1945-08-21 Gen Electric Cathode-ray deflecting means
US2414925A (en) * 1944-01-26 1947-01-28 Farnsworth Television & Radio Scanning and focusing yoke
US2443032A (en) * 1946-10-29 1948-06-08 Gen Electric Electromagnetic deflecting yoke and circuit
US2569343A (en) * 1949-02-26 1951-09-25 Rca Corp Deflection coil arrangement
US2645735A (en) * 1952-04-19 1953-07-14 Rca Corp Precision deflecting yoke
US2684455A (en) * 1952-06-13 1954-07-20 Bendix Aviat Corp Symmetrical magnetic deflection system
US2771563A (en) * 1950-06-25 1956-11-20 Int Standard Electric Corp Cathode ray deflection coils
US2831997A (en) * 1955-07-27 1958-04-22 Hazeltine Research Inc Electron-beam deflection yoke

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE748909C (de) * 1939-11-17 1944-11-25 Anordnung zur magnetischen Ablenkung von Kathodenstrahlen unter Verwendung von Spulen mit sinusfoermigem Strombelag

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB516743A (en) * 1937-07-06 1940-01-10 Telefunken Gmbh Improvements in or relating to electromagnetic deflecting systems for cathode ray tubes
US2383308A (en) * 1941-05-08 1945-08-21 Gen Electric Cathode-ray deflecting means
US2414925A (en) * 1944-01-26 1947-01-28 Farnsworth Television & Radio Scanning and focusing yoke
US2443032A (en) * 1946-10-29 1948-06-08 Gen Electric Electromagnetic deflecting yoke and circuit
US2569343A (en) * 1949-02-26 1951-09-25 Rca Corp Deflection coil arrangement
US2771563A (en) * 1950-06-25 1956-11-20 Int Standard Electric Corp Cathode ray deflection coils
US2645735A (en) * 1952-04-19 1953-07-14 Rca Corp Precision deflecting yoke
US2684455A (en) * 1952-06-13 1954-07-20 Bendix Aviat Corp Symmetrical magnetic deflection system
US2831997A (en) * 1955-07-27 1958-04-22 Hazeltine Research Inc Electron-beam deflection yoke

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3089761A (en) * 1958-05-16 1963-05-14 Socony Mobil Oil Co Inc Fuel oil composition
US3152291A (en) * 1960-03-10 1964-10-06 Telefunken Ag Magnetic deflection yoke
US3671896A (en) * 1971-05-21 1972-06-20 Sylvania Electric Prod Deflection system for triad-beam cathode ray tube

Also Published As

Publication number Publication date
GB840807A (en) 1960-07-13
BE553914A (en, 2012)
FR1185310A (fr) 1959-07-31
NL102926C (en, 2012)
CH349006A (de) 1960-09-30
DE1053677B (de) 1959-03-26

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