US3808568A - Stator yoke - Google Patents

Stator yoke Download PDF

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Publication number
US3808568A
US3808568A US00383137A US38313773A US3808568A US 3808568 A US3808568 A US 3808568A US 00383137 A US00383137 A US 00383137A US 38313773 A US38313773 A US 38313773A US 3808568 A US3808568 A US 3808568A
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United States
Prior art keywords
slots
core
deflection yoke
horizontal
square root
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
US00383137A
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English (en)
Inventor
C Sawyer
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.)
DISPLAY CO Inc
Original Assignee
DISPLAY CO Inc
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 US00383137A priority Critical patent/US3808568A/en
Application filed by DISPLAY CO Inc filed Critical DISPLAY CO Inc
Publication of US3808568A publication Critical patent/US3808568A/en
Application granted granted Critical
Priority to CA204,231A priority patent/CA992129A/en
Priority to GB2994374A priority patent/GB1466443A/en
Priority to DE2433989A priority patent/DE2433989A1/de
Priority to FR7425385A priority patent/FR2239002B3/fr
Priority to CH1016774A priority patent/CH581388A5/xx
Priority to JP8594574A priority patent/JPS5725941B2/ja
Priority to NL7410110A priority patent/NL7410110A/xx
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • H01J29/764—Deflecting by magnetic fields only using toroidal windings

Definitions

  • An improved electromagnetic deflection yoke core comprising an annular member of ferromagnetic material in which a plurality of slots are disposed along the interior perimeter thereof and are distributed in a given quadrant with respect to horizontal and vertical orthogonal axes which divide the core into four equal quadrants, the disposition or location of the slots being in accordance with an approximate cosine distribution about a 45 diagonal to said orthogonal axes.
  • This invention relates to electromagnets and more particularly to improved electromagnetic deflection yokes capable of being used with cathode ray tubes.
  • electromagnets can be used to create a magnetic field to control the path of an electron beam passing through the field. Consequently, electromagnets have been used to form deflection yokes which generally comprise a system of magnetic poles arranged around the neck of a cathode ray tube, between the electron gun and the face of the tube. The poles provide a magnetic .field to bend in a controlled manner an electron beam 'from its straight line path as it is transmitted from the electron gun toward the face of the tube. By suitably varying the magnetic field and simultaneously modulating'the intensity of the beam, the electron beam can'be made to sweep up and down and back and forth across the face of the tube forming a visual presentation or picture on the face of the tube.
  • One type of deflection yoke has saddle shaped coils, and is capable of two-directional beam deflection. Examples can be found in US. Pat. Nos. 2,766,407 and 3,430,169 respectively issued to Sanford and Gabor, and will be seen to comprise two pairs of coils. Each of the coils are formed of windings of conductive wire which are bunched together to form a figure similar to a saddle. The coils of each pair are located on opposite sides of the tube neck, and the coil pairs are displaced 90 around the tube. When energized, the two pairs of coils produce orthogonal magnetic fields through the neck of the tube perpendicular to the path of the undeflected electron beam generated in the tube.
  • yokes having saddle shaped coils also include a jacket or a sleeve of low reluctance material fitted snugly around the windings to help constrain the magnetic field and to increase the flux density through the neck of the tube.
  • the so-called magnetic toroid deflection yoke was developed to provide wide angle deflection with minimized pin-cushion distortion.
  • This type of deflection yoke which by way of example, is shown and described in U.S. Pat. No. 2,881,341 issued to Schlesinger, comprises an annular core or ring having longitudinally directed slots formed equiangularly around the interiorperimeter of the core. lnwardly directed teeth are thereby provided which are defined by those portions of the core between the slots.
  • the slots are identical with one another in terms of cross-sectional width and depth; and the teeth, although tapered in an axial direction are also identical with one another.
  • the number of slots and corresponding number of teeth are symmetrically arranged about'the horizontal or X axis and the vertical or Y axis in order to provide symmetry of both the X and Y field components. Accordingly, the number of slots or teeth are a multiple of four.
  • a coil section is provided for each of the slots, wherein wire is wound around the core through the respective slot. It is known that with this arrangement the structure when energized will approximate linear fields. The intensity of these fields is a function of the number of ampere turns or current density of each of the coils. Ampere turns or current densities of a coil section can be defined as the product Nl, where N is the number of turns of the coil section and I is the current transmitted therethrough.
  • the ampere turns distribution of the coil section of each quadrant theoretically requires a cosine distribution with respect to the horizontal or X axis for horizontal deflection, and a sine distribution with respect to the horizontal axis for vertical deflection.
  • the magnetic field in the vertical or Y direction can be controlled by controlling the current to the connected coil sections.
  • the magnetic toroid deflection yoke having equiangularly arranged slots has been found to be not wholly satisfactory.
  • the speed of deflection of the electron beam is proportional to the time rate of change of the number of ampere-turns. For rapid changes in beam position therefore, it is necessary that the coil sections provide a low inductance. Thus, for high speed changes in beam position the number of turns, N, for each coil section must be small because the inductance has to be small.
  • an object of the present invention is to provide a deflection yoke which overcomes the above noted problems of the prior art.
  • Another object of the present invention is to provide a magnetic deflection yoke in which errors resulting from coil turn approximation are substantially reduced.
  • Yet another object of the present invention is to provide a deflection yoke capable of providing a uniform magnetic field intensity.
  • Still another object of the present invention is to provide a deflection yoke which is particularly useful with large currents
  • Yet another object of the present invention is to provide a deflection yoke in which a small number of turns for each coil section may be utilized.
  • a deflection yoke comprising an annular core member having slots formed on the interior perimeter thereof and spaced from one another so that the slot density distribution approximates a cosine distribution about the 45 diagonal.
  • FIG. 1 is a side elevational view of a deflection yoke in accordance with the invention positioned on a cathode ray tube;
  • FIG. 2 illustrates cross-sectional view taken across the axis of symmetry of a deflection yoke designed in accordance with the invention.
  • FIG. 1 shows deflection yoke 8 located in operative position on cathode ray tube 10 which conventionally comprises a generally cylindrical neck portion 12 housing the usual electron gun 16.
  • Neck 12 is joined to flared or bulbous portion 14 of the tube, the end of which includes target screen 18 comprising a suitable electron-responsive material for emitting light in response to electron impingement.
  • target screen 18 comprising a suitable electron-responsive material for emitting light in response to electron impingement.
  • Deflection yoke 8 which is shown in greater detail in FIG. 2, comprises annular core member 20 having a plurality of radially directed alternating slots 22 and teeth 24 formed around the interior perimeter of the core in a manner which will be described in greater detail hereinafter.
  • Member 20 is made of any material which exhibits small magnetic losses, and has a relative permeability greater than'unity, such as any of the ferromagnetic materials.
  • the core is made of a ferrite, since ferrites assure low eddy-current losses. It is preferable to use a ferrite having a high maximum permeability and saturation with low coercive force and electrical conductivity. Manganese zinc ferrites which meet these requirements'are particularly useful since they can be made from inexpensive raw materials.
  • the core is typically made as a solid piece of ferrite. Alternatively, a laminated metal construction may be used, such as is provided by stacking a plurality of thin laminations of silicon iron.
  • Slots 22 are-preferably formed identically with one another so that they are of equal and constant cross sectional width and of equal cross sectional depth.
  • the number of slots are symmetrically arranged about the intersections of X and Y axes (the directions respectively of the horizontal and vertical components of the composite magnetic field. that is created) in order to provide horizontal and vertical field components. Accordingly, the total number of slotsare a multiple of four. Although the total number of slots is a matter of choice, a typical slotted yoke for sonar or radar use typically has sixteen slots.
  • Theangular position, of the center. of each of the slots which are located in the first quadrant (where i is the number of the given slot) is determined in a counter clockwise direction from the horizontal X axis and is defined as follows:
  • n is even, n being the total number of slots in the first quadrant on the core;
  • teeth 24 will vary in width, thereby providing linear magnetic fields of varying intensities.
  • a coil section 26 is provided for each of the slots 22, wherein wire is wound around the core member and as it is wound, it is disposed in the slot.
  • the turns of each coil section is typically equal in number so that each of the sections are equal in inductance. The invention works particularly well as mentioned above, when the number of turns is small.
  • the coil sections 26 are electrically connected together as well as to horizontal and vertical deflection control circuits (not shown) of the tube.
  • the horizontal deflection of the electron beam is controlled by the horizontal control circuit and the vertical deflection is controlled by the vertical control circuit.
  • the coil sections designated for horizontal deflection on each side of the Y axis are connected together in series to provide the horizontal deflection coils. These horizontal deflection coils are connected to the horizontal control circuit of the tube.
  • the coil sections designated for vertical deflection on each side of the X axis are connected together in series to provide the vertical coils. These vertical coils are connected to the vertical control circuit.
  • the slot configuration described in equations l and (2), above, generally is derived from the fact that when the electron beam is being deflected at a 45 diagonal to the X and Y axes, where the maximum distortion would occur, and the X and Y coil sections 26, are equal in inductance and in number of turns, in order to minimize the distortion, it can be shown that the ideal ampere turn distribution should be a cosine distribution about the 45 diagonal, or,
  • each slot has L wire turns from the X coil and Mi wire turns from the Y coil, where i is the number of the slot, as defined above. Since the inductance of each of the coil sections is equal about the 45 diagonal, the following criterion can be established:
  • each slot will have an equal number of turns or
  • the slots are arranged in accordance with equation (1) or (2).
  • the yoke is positioned on the neck 12 of tube 10.
  • the coil sections which are connected together to provide horizontal deflection are energized by the horizontal control circuit to deflect the beam in a horizontal direction as well known in the art.
  • the coil sections which are connected together to provide vertical deflection are energized by the vertical control circuit to deflect the beam in a vertical direction.
  • a core for an electromagnetic deflection yoke comprising,
  • a core for an electromagnetic deflection yoke comprising;
  • annular member of ferromagnetic material having a plurality of radially-directed slots disposed about the interior perimeter thereof, each of said slots being distributed along said perimeter of said core in a given quadrant with respect to horizontal and vertical orthogonal axes which divide said core into four equal quadrants, in accordance with the following relationships: 0i cos- V272 when n is even, and
  • i is an integer indicating the particular slot in said given quadrant counting the slots from said horizontal axis
  • 61' is the angular position of the ith slot with respect to said horizontal axis
  • n is the total number of slots in said given quadrant.
  • each of said slots is equal in cross-sectional width and depth.
  • An electromagnetic deflection yoke comprising,
  • annular core member of ferromagnetic material having a plurality of radially-directed slots disposed about the interior perimeter thereof
  • each of said coil sections having a plurality of turns and being disposed in a corresponding slot, wherein said slots are distributed in a given quadrant with respect to horizontal and vertical orthogonal axes which divide said core into four equal quadrants, in accordance with the following relationships: 0i cos ⁇ [2/2 when n is even, and
  • i is an integer indicating the particular slot in said given quadrant counting the slots from said horizontal axis
  • 6i is the angular position of the ith slot with respect to said horizontal axis
  • n is the total number of slots in said given quadrant.

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US00383137A 1973-07-27 1973-07-27 Stator yoke Expired - Lifetime US3808568A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US00383137A US3808568A (en) 1973-07-27 1973-07-27 Stator yoke
CA204,231A CA992129A (en) 1973-07-27 1974-07-05 Stator yoke
GB2994374A GB1466443A (en) 1973-07-27 1974-07-05 Electromagnetic defelction yoke
DE2433989A DE2433989A1 (de) 1973-07-27 1974-07-15 Elektromagnetisches ablenkjoch
FR7425385A FR2239002B3 (enExample) 1973-07-27 1974-07-22
CH1016774A CH581388A5 (enExample) 1973-07-27 1974-07-23
JP8594574A JPS5725941B2 (enExample) 1973-07-27 1974-07-26
NL7410110A NL7410110A (nl) 1973-07-27 1974-07-26 Kern voor een elektromagnetisch afbuigjuk.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00383137A US3808568A (en) 1973-07-27 1973-07-27 Stator yoke

Publications (1)

Publication Number Publication Date
US3808568A true US3808568A (en) 1974-04-30

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00383137A Expired - Lifetime US3808568A (en) 1973-07-27 1973-07-27 Stator yoke

Country Status (8)

Country Link
US (1) US3808568A (enExample)
JP (1) JPS5725941B2 (enExample)
CA (1) CA992129A (enExample)
CH (1) CH581388A5 (enExample)
DE (1) DE2433989A1 (enExample)
FR (1) FR2239002B3 (enExample)
GB (1) GB1466443A (enExample)
NL (1) NL7410110A (enExample)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4508989A (en) * 1983-05-19 1985-04-02 Display Components, Inc. Core element for electrodynamic rotary machine
US4566179A (en) * 1983-05-19 1986-01-28 Display Components, Inc. Core element for electrodynamic rotary machine
US4902994A (en) * 1987-09-09 1990-02-20 International Business Machines Corporation Deflecting device for a cathode ray tube

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5729238Y2 (enExample) * 1976-12-06 1982-06-25
JPH0760645B2 (ja) * 1987-04-20 1995-06-28 松下電器産業株式会社 偏向ヨ−ク
GB2429834C (en) * 2005-09-02 2011-08-24 Nanobeam Ltd Coil former
DE102006044060A1 (de) * 2006-09-20 2008-03-27 Abb Patent Gmbh Zwei- oder mehrdimensionale Wicklungsanordnung und Verfahren zur Reduktion der Kopplungen zwischen Resonanzwicklungen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2846606A (en) * 1952-06-05 1958-08-05 Philips Corp Television receiver

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2846606A (en) * 1952-06-05 1958-08-05 Philips Corp Television receiver

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4508989A (en) * 1983-05-19 1985-04-02 Display Components, Inc. Core element for electrodynamic rotary machine
US4566179A (en) * 1983-05-19 1986-01-28 Display Components, Inc. Core element for electrodynamic rotary machine
US4902994A (en) * 1987-09-09 1990-02-20 International Business Machines Corporation Deflecting device for a cathode ray tube

Also Published As

Publication number Publication date
GB1466443A (en) 1977-03-09
CH581388A5 (enExample) 1976-10-29
CA992129A (en) 1976-06-29
JPS5045515A (enExample) 1975-04-23
JPS5725941B2 (enExample) 1982-06-01
DE2433989A1 (de) 1975-02-13
FR2239002B3 (enExample) 1977-05-20
FR2239002A1 (enExample) 1975-02-21
NL7410110A (nl) 1975-01-29

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