US3851215A - Deflection coil system for colour television - Google Patents

Deflection coil system for colour television Download PDF

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Publication number
US3851215A
US3851215A US00290651A US29065172A US3851215A US 3851215 A US3851215 A US 3851215A US 00290651 A US00290651 A US 00290651A US 29065172 A US29065172 A US 29065172A US 3851215 A US3851215 A US 3851215A
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United States
Prior art keywords
deflection
coil
coils
sections
parallel
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Expired - Lifetime
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US00290651A
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English (en)
Inventor
J Dekeijser
A Kuiper
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US Philips Corp
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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
    • H01J29/762—Deflecting by magnetic fields only using saddle coils or printed windings
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/96—Circuit elements other than coils, reactors or the like, associated with the tube
    • H01J2229/964—Circuit elements other than coils, reactors or the like, associated with the tube associated with the deflection system

Definitions

  • the invention relates to a deflection coil system for a colour television display tube, comprising deflection coils for electron beam deflection in the horizontal and the vertical direction, respectively, each coil consisting of a number of turns of a conductive wire, each of the coils for at least one of the two deflection directions being divided into a number of series-connected sections in that at least one turn which is situated between the first and the last turn of the coil is provided with a tapping.
  • Contemporary colour television display tubes usually comprise three electron guns which are preferably arranged at the comers of an equilateral triangle or are adjacently arranged on one line. Each of these electron guns generates an electron beam which, after having passed through one of the apertures in a shadow mask, impinges upon a phosphor dot on a rectangular display screen, the said phosphor dot thereby luminescing a given colour.
  • the electron beams can be deflected such that they scan the entire display screen.
  • the dynamic convergence of the beams is of major importance in this respect. This means that, regardless of the angle through which the beams have been deflected, the three beams must always intersect each other at the area of the shadow mask so as to cause luminescence of the correct phosphor dots.
  • This dynamic convergence greatly depends on the distribution of the turns of the wires constituting the deflection coils. During the manufacture of the coils, deviations occur in the turn distribution which cause a difference in the dynamic convergence in individual coil systems. Such differences are not acceptable, particularly in the case of colour television display tubes having large deflection angles.
  • each of the coils is woundwith a number of parallel wires, the coil being divided into a number of series-connected sections by means of tappings.
  • the parallel wires of some of these sections are connected in parallel, and the parallel wires of other sections are connected in series.
  • the effective turn distribution of the finished product can be influenced by varying the number of turns per section when the coil is being wound.
  • a drawback of this method is that the correction must be performed during winding, whilst the correction must also be rather coarse because a difference of at least one complete turn must each time be introduced.
  • the invention has for its object to eliminate these drawbacks by providing a deflection coil system in which the effective turn distribution of the finished product can be changed while it has already been mounted on the display tube, arbitrarily small variations also being possible.
  • a deflection coil system is characterized in that at least one of the sections of each of the coils for at least one deflection direction is connected in parallel with a circuit of adjustable impedance.
  • One embodiment of the system according to the invention by means of which the convergence can be influenced on the entire display screen is characterized in that at least the first .or the last section of the relevant coils is provided with a parallel circuit.
  • FIG. 1 is a perspective view of a saddle-shaped deflection coil which forms part of a. deflection coil system according to the invention
  • FIG. 2 is a diagrammatic cross-sectional view of a ferromagnetic core having vertical saddle-shaped deflection coils
  • FIG. 3 is a diagrammatic cross-sectional view of a ferromagnetic core having vertical toroidal deflection coils
  • FIGS. 4 and 5 are diagrammatic views of two methods of dividing the coils of FIGS. 2. and 3 into sections in accordance with the invention, and
  • FIGS. 6a, 6b and 7a, 7b show a number of practical circuits for a deflection coil system according to the invention.
  • the saddle-shaped deflection coil shown in FIG. 1 is intended to be arranged on the outside of a display tube (not shown) so as to deflect an electron beam which is generated in the tube and whose direction of travel is denoted by an arrow 1.
  • the coil consists of a number of turns of a conductive wire which. is composed of one or more strands, preferably copper wire, which enve lope a window 3.
  • the coil comprises active parts 5 and 7 in which the wire extends mainly parallel to the direction of travel of the electrons, and a foremost coil end 9 and a rearmost coil end 11 where the wire extends substantially at right angles to the said direction of travel.
  • the electrons are deflected substantially exclusively by the magnetic field which is generated in the active parts 5 and 7.
  • connection wires 13 and 15 The current required for the deflection can be supplied via connection wires 13 and 15 at the area of the rearmost coil end 11. Two turns are provided with tappings l7 and 19 that are also located at the rearmost coil end 11. As a result, the coil is divided into three sections, the first section consisting of the turns between the connection wire 13 and the first tapping 17, the second section consisting of the turns between the two tappings l7 and 19, and the third section consisting of the turns between thesecond tapping l9 and the connection wire 15. Connected in parallel to each of the three sections is a circuit 21 which has an adjustable impedance. Part of the deflection current which is applied to the coil via the supply wires 13 and 15 passes through a coil section while the remainder passes through the parallel circuit 21 which is associated with this section.
  • FIG. 2 is a diagrammatic cross-sectional view of an angular ferromagnetic core 23 which .surrounds a pair of saddle-coils, only the active parts 5 and 7 and 5 and 7 thereof being visible in FIG. 2.
  • the coils are arranged with respect to each other such that the connection line between the two windows 3 and 3' extends horizontally and intersects the axis of the core 23.
  • the magnetic field which generates a current which flows through these coils causes a vertical deflection of an electron beam (not shown) travelling at right angles to the plane of the drawing.
  • the deflection direction is denoted in the FIGS. 2 to 5 by a double arrow 25.
  • a complete deflection coil system is also provided with a second pair of saddle coils (not shown for the sake of clarity), which are arranged to be coaxial with the first pair and which have been turned through an angle of 90 with respect to the first pair so that the connection line between the windows of the second coil pair extends in the vertical direction.
  • the effect'of themagnetic field which is generated by each turn of the coil on the deflection of the electrons is dependent on the location of this turn.
  • This location is determined by measuring, in a plane perpendicular to the direction of travel of the electron beam, for example, the plane of the drawing in the FIGS. 2 to 5, the angle between the deflection direction of the coil on the one side and the connection line from the axis of the core 23 to the relevant turn on the other side.
  • FIG. 2 shows the angular distance a, of the turns which are arranged nearest to the deflection direction, and the angular distance a of the turns which are arranged furthest from the deflection direction.
  • the mean angular distance oz can be calculated from the angular distances of the turns by means of the formula:
  • the deflection coils consist of four coils 29, 31, 33 and 35 which are toroidally wound about the core.
  • the various angular distances 0, can be determined with reference to FIG. 3 in the same manner as for saddle-coils with reference to the FIG. 2.
  • the calculation of the mean angular distance or, is also the same.
  • the mean turns are denoted in FIG. 3by 37, 39, 41 and 43.
  • FIG. 4 a subdivision into sections of the saddle coils of FIG. 2 is shown diagrammatically. By means of four'tappings (not shown) each of the two coils is divided into five sections 45, 47, 49, 51, 53 and 45, 47',
  • each of these sections can be provided with a parallel circuit (not shown in FIG. 4). However, it appears to be particularly advantageous to provide one or more of the sections 45, 49 and 53 with a parallel circuit.
  • the parallel circuit of the first section 45 and of the last section 53 can be utilized to influence the location of the mean turn 27. By reducing the impedance of the parallel circuit of section 45, the current flowing through this section is reduced. As regards the magnetic field which is generated by the coil this has the same effect as a reduction of the number of turns in this section and hence of the factors n(a) in the formula for u As these factors remain the same in the other sections, it is obvious that the value oz, increases as a result thereof.
  • the convergence in the comer-s of the display screen is also dependent of the location of the mean turn 27. However, this convergence is also dependent of the manner in which the turns are distributed over the width of the coil. By influencing this distribution without changing the location of the mean turn 27 to any significant extent, optimum adjustment can be achieved of the convergence in the comers of the display screen without the already adjusted convergence on the axes being disturbed.
  • the section 49, extending on both sides of the mean turn, is also provided with a parallel circuit.
  • each of the coils comprising turns, each coil was divided by means of tappings such that each of the sections 45, 49 and 53 comprises ten turns.
  • the mean turn 27 of the uncorrected coil is always shifted in one direction with respect to the desired location.
  • the mean turn 27 must always be displaced in the same direction upon correction, so that for this purpose only section 45 or only section 53 must be provided with a parallel circuit. That one of these two sections which is not used need not even exist as a separate section in that case, so that the relevant tapping can also be omitted.
  • the sections 47 and 51 which are not provided with a parallel circuit can also be omitted.
  • the situation shown in FIG. 5 is obtained where the coil, in accordance with FIG. 1, is divided into only three sections 45, 49 and 53.
  • the coil is wound such that the mean turn is always shifted in the direction of, for example, section 53.
  • the tapping which limits section 53
  • an impedance is connected parallel to section 53.
  • the convergence in the corners and on the axes of the display screen is simultaneously adjusted by variation of this impedance. Obviously, this is possible only if this combined convergence adjustment constituted an acceptable compromise.
  • FIG. 2 As a basis, the division into sections has been described for saddle coils with reference to the FIGS. 4 and S. It is obvious that on the basis of FIG. 3 analogous figures for toroidal coils can be drawn which are subject to the same considerations. It is also possible to incorporate in one deflection coil system saddle coils for the deflection in the one direction and toroidal coils for the deflection in the other direction. This does not affect the above-mentioned considerations either.
  • the circuits which are connected parallel to the various sections preferably consist of variable resistors for the vertical deflection coils which are supplied with a deflection voltage of low frequency.
  • coils having a variable inductance are preferably used as the parallel circuit.
  • FIGS. 6 and 7 show some examples of circuits which can be used for deflection coil systems according to the invention.
  • FIG. 6a shows a pair of saddle-shaped horizontal deflection coils which are divided into sections 45, 47, 49, 51 and 53 and 45, 47', 49, 61' and 53, respectively.
  • the coils are connected in series via a variable coil 55 which serves for compensation of mutual differences, and they are earthed in the centre of the series network. They are supplied from a known sawtooth gener ator 57.
  • a coil having a variable inductance Connected in parallel to each of the sections 45, 49, 53, 45 49' and 53' is a coil having a variable inductance. These coils are denoted by 59, 61, 63, 59, 61' and 63, respectively.
  • FIG. 6b shows an analogous circuit for saddle-shaped vertical deflection coils.
  • the sections are numbered in the same manner as in FIG. 6a.
  • Connected in parallel with each of the sections 45, 49, 53, 45', 49' and 53 is a variable resistor. These resistors are denoted by 65, 67, 69, 65', 67' and 69, respectively.
  • the assembly is supplied from a known sawtooth. generator 71.
  • the voltage at the area of the centre of the series network can be adjusted by means of a potentiometer 73 which constitutes, on conjunction with the two fixed resistors 75 and 77, a voltage divider which is connected in parallel with the series network.
  • FIGS. 6a and 6b It appears from FIGS. 6a and 6b that, if the two deflection coils for one deflection direction are connected in series, a separate variable resistor or coil is required for each section provided with a parallel circuit. It appears that the number of variable resistors and coils can be reduced to one half by parallel connection of the deflection coils. This not only represents a saving as regards the number of components required for the circuit, but also the number of operations to be performed for adjustment is reduced.
  • FIGS. 7a and b show how such a circuit can be constructed for the horizontal and the vertical deflection coils, respectively.
  • each coil is again divided into five sections, the numbering of which corresponds to that in FIGS. 6a and b.
  • Sections forming part of different coils are pairwise connected in parallel. As a result, the following pairs of sections are obtained: 45 and 53', 47 and 51', 49 and 49, 51 and 47'. 53 and 45.
  • FIG. 7a shows that a coil having a variable inductance 79 is connected parallel to the first pair of sections 45, 53' of the horizontal deflection coils.
  • variable coil 81 is connected parallel to the third pair of sections 49, 49', and a variable coil 83 is connected parallel to the fifth pair 53, 45.
  • the complete parallel network is again supplied from the sawtooth generator 57 via a variable coil 85 for compensating differences between the two deflection coils.
  • FIG. 7b shows that a variable resistor 87 is connected parallel to the first pair of sections 45, 53 of the vertical deflection coils, a variable resistor 89 being connected parallel to the third pair 49, 49, and a variable resistor 91 being connected parallel to the fifth pair 53, 45'.
  • a variable resistor 93 for the elimination of irregularities in the two deflection coils, the complete parallel network is again supplied by the sawtooth generator 71.
  • a deflection coil system for a colour television display tube comprising deflection coils for electron beam deflection in the horizontal and the vertical direction, respectively, each coil being a single coil and consisting of a number of turns of a conductive wire, each of the coils for at least one of the two deflection directions being divided into a number of seriesconnected sections in that at least one turn which is situated between the first and the last turn of the coil is provided with a tapping, characterized in that at least one of the sections of each of the coils for at least one deflection direction, is connected in parallel with a circuit means of adjustable impedance for adjusting the dynamic convergence.
  • a deflection coil system as claimed in claim 1 characterized in that at least the first (45) or the last (cos a )-n(a) id-M 4.
  • each of the sections provided with a parallel circuit comprises a number of turns substantially equal to one tenth of the total number of turns of the relevant coil.
  • each of the parallel circuits (2]) of the horizontal deflection coils consists of a coil (59, 61, 63) of adjustable inductance, each of the parallel circuits (21) of the vertical deflection coils consisting of a variable resistor (65, 67, 69).
  • sections (45, 53'; 49, 49; 53, 45') which form part of different coils are pair-wise connected in parallel.
  • a deflection coil system for a color television display tube comprising a pair of single deflection coils for electron beam deflection in the horizontal and the vertical directions respectively, each coil comprising a plurality of turns of a conductive wire, one of said coils having a tap dividing said one coil into a plurality of series-connected sections, and means parallel coupled to at least one of the sections of each of the coils for adjusting the dynamic convergence of the tube comprising an adjustable impedance element.
  • n(a) represents the number of turns whose angular distance to the deflection direction amounts to a and N is the total number of turns of the coil.
  • a deflection coil system for a color television display tube comprising a pair of single deflection coils for electron beam deflection in the horizontal and the vertical directions respectively, each coil comprising a plurality of turns of a conductive wire, one of said coils having a tap dividing said one coil into a plurality of series-connected sections, means parallel coupled to at least one of the sections of each of the coils for adjusting the dynamic convergence of the tube comprising an adjustable impedance element, and wherein one of said sections which is provided with a parallel circuit extends on both sides of a mean turn the angular distance a, between said mean turn and the deflection direction associated with this coil satisfying the formula:
  • N is the total number of turns of the coil.

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US00290651A 1971-09-21 1972-09-20 Deflection coil system for colour television Expired - Lifetime US3851215A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7112929A NL7112929A (fr) 1971-09-21 1971-09-21

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US (1) US3851215A (fr)
JP (1) JPS4839112A (fr)
CA (1) CA957006A (fr)
DE (1) DE2245295C3 (fr)
ES (1) ES406833A1 (fr)
FR (1) FR2153370B1 (fr)
GB (1) GB1339881A (fr)
IT (1) IT967579B (fr)
NL (1) NL7112929A (fr)
SE (1) SE410538B (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4095143A (en) * 1976-07-21 1978-06-13 Gte Sylvania Incorporated Electron beam crossover correction circuitry
US4280080A (en) * 1978-09-14 1981-07-21 International Standard Electric Corporation Deflection-coil system for color picture tubes
US5028850A (en) * 1990-07-19 1991-07-02 Rca Licensing Corporation Deflection system with a controlled beam spot
US5039922A (en) * 1987-08-17 1991-08-13 Mitsubishi Denki Kabushiki Kaisha CRT deflection yoke with ringing suppression
US5327051A (en) * 1990-07-19 1994-07-05 Rca Thomson Licensing Corporation Deflection system with a pair of quadrupole arrangements
USRE35548E (en) * 1989-10-02 1997-07-01 U.S. Philips Corporation Color display tube system with reduced spot growth
EP1152449A2 (fr) * 2000-04-28 2001-11-07 Matsushita Electric Industrial Co., Ltd. Dispositif à tube à rayon cathodique

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2411486A1 (fr) * 1977-12-07 1979-07-06 Videon Sa Bobine de deviation perfectionnee
NL170573C (nl) * 1978-01-18 1982-11-16 Philips Nv Afbuiginrichting voor een kleurentelevisiebeeldbuis.
US4759771A (en) * 1987-05-21 1988-07-26 Sgs-Thomson Microelectronics, Inc. Packaging technique for batteries
US5397968A (en) * 1992-09-18 1995-03-14 Victor Company Of Japan, Ltd. Deflection yoke
DE102015223091A1 (de) 2015-11-23 2017-05-24 Continental Reifen Deutschland Gmbh Fahrzeugluftreifen

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2228821A (en) * 1938-10-01 1941-01-14 Gen Electric Magnetic sweep coil circuit
US2866125A (en) * 1954-02-09 1958-12-23 Philips Corp Cathode-ray tube
US3169207A (en) * 1962-06-11 1965-02-09 Rca Corp Electromagnetic deflection yoke having interconnected multifilar strands
US3456149A (en) * 1964-02-12 1969-07-15 Hollandse Signaalapparaten Bv Magnetic deflecting means for cathode-ray tubes

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS452401Y1 (fr) * 1968-06-27 1970-01-31

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2228821A (en) * 1938-10-01 1941-01-14 Gen Electric Magnetic sweep coil circuit
US2866125A (en) * 1954-02-09 1958-12-23 Philips Corp Cathode-ray tube
US3169207A (en) * 1962-06-11 1965-02-09 Rca Corp Electromagnetic deflection yoke having interconnected multifilar strands
US3456149A (en) * 1964-02-12 1969-07-15 Hollandse Signaalapparaten Bv Magnetic deflecting means for cathode-ray tubes

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4095143A (en) * 1976-07-21 1978-06-13 Gte Sylvania Incorporated Electron beam crossover correction circuitry
US4280080A (en) * 1978-09-14 1981-07-21 International Standard Electric Corporation Deflection-coil system for color picture tubes
US5039922A (en) * 1987-08-17 1991-08-13 Mitsubishi Denki Kabushiki Kaisha CRT deflection yoke with ringing suppression
USRE35548E (en) * 1989-10-02 1997-07-01 U.S. Philips Corporation Color display tube system with reduced spot growth
US5028850A (en) * 1990-07-19 1991-07-02 Rca Licensing Corporation Deflection system with a controlled beam spot
US5327051A (en) * 1990-07-19 1994-07-05 Rca Thomson Licensing Corporation Deflection system with a pair of quadrupole arrangements
US5489824A (en) * 1990-07-19 1996-02-06 Rca Thomson Licensing Corporation Deflection system with a controlled beam spot
EP1152449A2 (fr) * 2000-04-28 2001-11-07 Matsushita Electric Industrial Co., Ltd. Dispositif à tube à rayon cathodique
US6489734B2 (en) * 2000-04-28 2002-12-03 Matsushita Electric Industrial Co., Ltd. Cathode ray tube device
EP1152449A3 (fr) * 2000-04-28 2004-02-18 Matsushita Electric Industrial Co., Ltd. Dispositif à tube à rayon cathodique

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Publication number Publication date
ES406833A1 (es) 1975-10-16
JPS4839112A (fr) 1973-06-08
DE2245295B2 (de) 1979-07-05
NL7112929A (fr) 1973-03-23
FR2153370A1 (fr) 1973-05-04
FR2153370B1 (fr) 1977-07-29
CA957006A (en) 1974-10-29
DE2245295C3 (de) 1980-02-28
GB1339881A (en) 1973-12-05
IT967579B (it) 1974-03-11
SE410538B (sv) 1979-10-15
DE2245295A1 (de) 1973-03-29

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