EP0540096B1 - Ablenkjochvorrichtung mit Mitteln zur Verringerung von Leckmagnetfeldern - Google Patents

Ablenkjochvorrichtung mit Mitteln zur Verringerung von Leckmagnetfeldern Download PDF

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Publication number
EP0540096B1
EP0540096B1 EP92203252A EP92203252A EP0540096B1 EP 0540096 B1 EP0540096 B1 EP 0540096B1 EP 92203252 A EP92203252 A EP 92203252A EP 92203252 A EP92203252 A EP 92203252A EP 0540096 B1 EP0540096 B1 EP 0540096B1
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EP
European Patent Office
Prior art keywords
deflection
magnetic
core
coils
magnetic field
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
EP92203252A
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English (en)
French (fr)
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EP0540096A1 (de
Inventor
Hans C/O Int. Octrooibureau B.V. Meershoek
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.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips Electronics NV
Philips Electronics NV
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Publication date
Application filed by Koninklijke Philips Electronics NV, Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Priority to EP92203252A priority Critical patent/EP0540096B1/de
Publication of EP0540096A1 publication Critical patent/EP0540096A1/de
Application granted granted Critical
Publication of EP0540096B1 publication Critical patent/EP0540096B1/de
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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
    • H01J29/003—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
    • H01J2229/0015—Preventing or cancelling fields leaving the enclosure
    • H01J2229/0023—Passive means

Definitions

  • the invention relates to a deflection yoke apparatus to be mounted on a neck of cathode-ray tube for projecting rasters on a screen by scanning with at least one electron beam, comprising
  • the leaking magnetic field of a deflection unit is not very strong; at a distance of 50 cm from the front side of a deflection unit for a 110° monochrome display tube the field strength has already decreased to approximately 1% of the strength of the earth's magnetic field, but it is the variation of the leaking field with respect to time which is important. Field variations may cause electromagnetic interferences in other electronic apparatus which causes these electronic apparatuses to malfunction. Also research is being done to establish whether human health is affected by these leaking fields.
  • the time derivative of the field of the deflection yoke apparatus increases with the increase of the line frequencies and hence with increasingly shorter fly-back periods.
  • a compensation coil means which, when energized, generates a compensating magnetic dipole field has been proposed in EP-A-220 777.
  • This dipole field can be obtained by energizing one auxiliary coil whose turns have been wound around a bobbin in a square form which coil has the correct number of turns, the correct surface area and the correct orientation.
  • Energization may be effected, for example, by arranging the said coil in series with or parallel to the pair of horizontal deflection coils.
  • the compensation field may be obtained alternatively by energizing two of such auxiliary coils which are positioned on either side of the deflection yoke apparatus which auxiliary coils have the correct number of turns, the correct surface area and the correct orientation. Also in this case energization may be effected, for example, by arranging the auxiliary coils in series with or parallel to the pair of horizontal coils.
  • the auxiliary coils are preferably large so as to reduce their energy content.
  • auxiliary coils can only be used so that the compensation of the leaking fields consumes much (deflection) energy.
  • the sensitivity of the pair of horizontal deflection coils is affected if the known auxiliary coils are arranged in series with them. The induction then increases.
  • each auxiliary coil means has an auxiliary coil and a magnetic rod made of soft magnetic material as a magnetic core for said coil.
  • the magnetic rods are positioned relative to the screen-side end of the deflection core in a magnetic flux coupling relationship with it.
  • the effectiveness of the inventive solution for radiation compensation is both superior to solutions which are based on the use of rod-shaped auxiliary core means of a magnetizable material provided with (toroidal) auxiliary coils, is both superior to solutions which are based on the use of coreless, i.e. air-cored auxiliary coils and to solutions which are based on the use of auxiliary coils wound on magnetic rods which are not engaging the smaller diameter end of the deflection core in magnetic flux coupling relationship.
  • the inventive solution was found to compensate the leaking fields effectively, while there was a reduced loss of deflection sensitivity (in a given case, for example, a reduction by a factor 5 as compared with conventional auxiliary coil means).
  • the assembly of deflection core and magnetic rods acts, as it were, like one magnetic core of minimum length.
  • An engaging means is provided for engaging the magnetic rods of the auxiliary coil means in the required magnetic flux-coupling relationship with the deflection core.
  • a preferred embodiment of the invention is characterized in that said engaging means comprises an annular member through which the deflection core passes, which annular member has two support members which support the magnetic rods in inclined positions towards the smaller diameter end of the deflection core, and connection parts which connect the annular member to the expanded part of the coil separator.
  • This construction provides a stable and simple support for supporting the magnetic rods of the auxiliary coil means in a desired angled relationship with the smaller diameter end of the deflection core.
  • the stability may be improved by bonding the end faces of the magnetic rods to the deflection core.
  • connection parts in the form of click-on mounts may be improved by using connection parts in the form of click-on mounts.
  • annular ferrite core 10 is supported on a coil separator 13 made of plastic resin material around which vertical deflection coils 11 and 12 are arranged. Inside the coil separator 13 a pair of horizontal deflection coils 14 and 15 is arranged. On the exterior of the deflection core 10, auxiliary coil devices 16 and 17 are slantly arranged in the vertical direction on the drawing and engage the smaller diameter end of the core 10.
  • Figure 2 shows a front view of the apparatus in Figure 1 and the deflection core 10 is located at the coordinate position where it is divided into four equal portions by X and Y axes.
  • a pair of horizontal deflection coils 14 and 15 are respectively arranged at upper and lower sides in reference to the X axis so that they are arranged symmetrically in reference to the Y axis.
  • the auxiliary coil devices are located at the positions in the Y-axis direction equally away from the X axis and the parallel to the Y-Z plane.
  • An essential aspect of the invention is the relationship between the deflection core 10 in the interior of which vertical deflection coils 11 and 12 and horizontal deflection coils 14, 15 are disposed and the auxiliary coil devices 16 and 17.
  • Auxiliary coils 18 and 19 are wound on magnetic rods 20 and 21 with high magnetic permeability made of ferrite, permalloy, silicon steel sheet or other material, the lengths of which are almost equal to the length of the deflection core 10 in the axial direction of the core to intensify the magnitude of magnetic field generated when a current is supplied to the auxiliary coils.
  • Auxiliary coils 18 and 19 may be made up by winding several times 0.4 mm diameter copper wires which are stranded or bound, and these auxiliary coils may be connected in series to horizontal deflection coils 14 and 15. Accordingly, a current as large as the current flowing through the horizontal deflection coils is supplied to auxiliary coils 18 and 19.
  • the magnetic rods 20, 21 had a length of 60 mm and a diameter of 5 mm, and they were made of 4C6 ferrite. Rod lengths of, for example, between 5 and 10 cm were found to be suitable in practice.
  • auxiliary coils 18, 19 are wound having a limited number of turns (in connection with the induction).
  • the vertical deflection coils 11, 12 are of the saddle type: they are arranged inside the deflection core 10 and do not extend along the outer surface of the deflection core 10.
  • the rods 20,21 preferably are bonded to the core 10 by means of an adhesive.
  • the rods 20,21 are supported by an annular member 22 which is provided with connecting parts 36a, 36b. which connect the annular member 22 to the front expanded part 13a of the coil separator 13.
  • the connections are of the click-on type.
  • the annular member 22, through which the core 10 passes, is provided with support members 23, 24 in which fit the magnetic rods 20, 21.
  • the use of magnetic rods is determined according to the design of each type of the deflection yoke apparatus.
  • the external sizes of auxiliary coils 18 and 19, number of turns of said coils, diameters of conductors used in these cols, etc. are determined taking into account the impedance of the horizontal deflection coils, magnitude of the externally leaking magnetic field, frequency of the current flowing through said coils 18 and 19, etc.
  • the deflection yoke apparatus in accordance with the present invention can reduce the externally leaking magnetic field radiated from the deflection coils, in other words, an unwanted radiation and minimize electromagnetic interference to other electronic equipment.
  • the deflection yoke apparatus of the present invention can be modified in the design within the scope of the appended claims.

Claims (2)

  1. Ablenkjochvorrichtung zur Befestigung auf einem Hals einer Elektronenstrahlröhre zum Projizieren von Rastern auf einem Schirm durch Abtastung mit wenigstens einem Elektronenstrahl, mit:
    (a) einem Paar Horizontal-Ablenkspulen (14, 15) zum Erzeugen eines Magnetfeldes zur Ablenkung des genannten Elektronenstrahls in einer horizontalen Richtung,
    (b) einem Paar Vertikal-Ablenkspulen (11, 12) zum Erzeugen eines Magnetfeldes zur Ablenkung des genannten Elektronenstrahls in einer vertikalen Richtung,
    (c) einem Spulentrenner (13) zur elektrischen Isolierung zwischen den genannten zwei Ablenkspulen, wobei dieser Spulentrenner am vorderen Ende mit einem erweiterten Teil versehen ist,
    (d) einem ringförmigen, trichterförmigen Ablenkkern (10), der für einen magnetischen Fluß eine magnetische Strecke bildet, wobei dieser Fluß erzeugt wird, wenn der Horizontal- und der Vertikal-Ablenkspule ein Ablenkstrom zugeführt wird, und ein Ablenkmagnetfeld bildet zum Ablenken des genannten Elektronenstrahls innerhalb des genannten Ablenkkerns und ein äußeres Leckmagnetfeld bildet, außerhalb des Ablenkkerns,

    gekennzeichnet durch
    (e) zwei Hilfsspulenmittel (16, 17), die an einander diametral gegenüberliegenden Stellen in der genannten vertikalen Richtung außerhalb des Ablenkkerns zum Erzeugen eines Magnetfeldes vorgesehen sind, in einer Richtung, die der Richtung des genannten äußeren Leckmagnetfeldes entgegengesetzt ist wenn den Mitteln ein Horizontal-Ablenkstrom zugeführt wird, wobei jedes Hilfsspulenmittel eine Hilfsspule (18, 19) sowie einen aus weichmagnetischem Material hergestellten Magnetstab (20, 21) als Magnetkern für die genannte Spule aufweist, und
    (f) ein Beeinflußungsmittel zum Beeinflußen der Magnetstäbe der genannten Hilfsspulenmittel, die mit dem Ende des Ablenkkerns mit kleinerem Durchmesser in einer Flußkoppelbeziehung stehen.
  2. Ablenkjochvorrichtung nach Anspruch 1, wobei die genannten Beeinflußungsmittel ein ringförmiges Element (22) aufweisen, durch das der Ablenkkern hindurchgeht, wobei dieses ringförmige Element zwei Träger (23, 24) aufweist, welche die Magnetstäbe in schrägen Lagen in Richtung zu dem Ende mit dem kleineren Durchmesser des Ablenkkerns tragen, und Verbindungsteile (36a, b) , die das ringförmige Element mit dem erweiterten Teil (13a) des Spulentrenners verbinden.
EP92203252A 1991-10-30 1992-10-22 Ablenkjochvorrichtung mit Mitteln zur Verringerung von Leckmagnetfeldern Expired - Lifetime EP0540096B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP92203252A EP0540096B1 (de) 1991-10-30 1992-10-22 Ablenkjochvorrichtung mit Mitteln zur Verringerung von Leckmagnetfeldern

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP91202801 1991-10-30
EP91202801 1991-10-30
EP92203252A EP0540096B1 (de) 1991-10-30 1992-10-22 Ablenkjochvorrichtung mit Mitteln zur Verringerung von Leckmagnetfeldern

Publications (2)

Publication Number Publication Date
EP0540096A1 EP0540096A1 (de) 1993-05-05
EP0540096B1 true EP0540096B1 (de) 1996-01-03

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EP92203252A Expired - Lifetime EP0540096B1 (de) 1991-10-30 1992-10-22 Ablenkjochvorrichtung mit Mitteln zur Verringerung von Leckmagnetfeldern

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EP (1) EP0540096B1 (de)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5036250A (en) * 1988-06-14 1991-07-30 U.S. Philips Corporation Picture display device with core means comprising compensation coils
KR920001582Y1 (ko) * 1989-12-23 1992-03-05 삼성전관 주식회사 편향요크

Also Published As

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EP0540096A1 (de) 1993-05-05

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