EP0476609A2 - Magnetkreis mit Permanentmagnet - Google Patents

Magnetkreis mit Permanentmagnet Download PDF

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Publication number
EP0476609A2
EP0476609A2 EP91115830A EP91115830A EP0476609A2 EP 0476609 A2 EP0476609 A2 EP 0476609A2 EP 91115830 A EP91115830 A EP 91115830A EP 91115830 A EP91115830 A EP 91115830A EP 0476609 A2 EP0476609 A2 EP 0476609A2
Authority
EP
European Patent Office
Prior art keywords
magnetic
pair
permanent magnet
opposite
magnetic circuit
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.)
Granted
Application number
EP91115830A
Other languages
English (en)
French (fr)
Other versions
EP0476609B1 (de
EP0476609A3 (en
Inventor
Masami C/O Tdk Corporation Oguriyama
Yoshio C/O Tdk Corporation Ishigaki
Haruo Okano
Isahiro Hasegawa
Jun-Ichi C/O Tokyo Electron Limited Arami
Hiromi C/O Tokyo Electron Limited Harada
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.)
Toshiba Corp
Tokyo Electron Ltd
TDK Corp
Original Assignee
Toshiba Corp
Tokyo Electron Ltd
TDK Corp
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
Application filed by Toshiba Corp, Tokyo Electron Ltd, TDK Corp filed Critical Toshiba Corp
Publication of EP0476609A2 publication Critical patent/EP0476609A2/de
Publication of EP0476609A3 publication Critical patent/EP0476609A3/en
Application granted granted Critical
Publication of EP0476609B1 publication Critical patent/EP0476609B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/02—Permanent magnets [PM]
    • H01F7/0205—Magnetic circuits with PM in general
    • H01F7/021—Construction of PM
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets

Definitions

  • This invention relates to a permanent magnet magnetic circuit.
  • Such permanent magnet magnetic circuits are used in semiconductor manufacturing apparatus and similar apparatus requiring a unidirectional magnetic field having linear lines of magnetic force in a desired region and especially useful when restrictions are imposed on their attachment or arrangement.
  • the circuit includes a U-shaped yoke 2 having opposed legs.
  • a pair of permanent magnets 1A and 1B are attached to the inside surfaces of the yoke legs such that the N pole of one magnet 1A is opposed to the S pole of the other magnet 1 B.
  • This arrangement creates a unidirectional magnetic field containing least of unnecessary perpendicular magnetic field components.
  • a region E1 where the unidirectional magnetic field is produced is surrounded at three sides by the magnetic circuit.
  • This magnetic circuit is not useful where restrictions are imposed on its attachment or location.
  • this first prior art circuit cannot be applied under the requirement that the magnetic circuit should not protrude beyond the lower boundary line F1 of the unidirectional magnetic field generating region E1.
  • Such restrictions arise, for example, when it is desired for a magnetic circuit located outside a vacuum vessel to provide a region E1 of unidirectional magnetic field within the vacuum container interior.
  • FIGS. 12 and 13 show a second example of the prior art, illustrating a most fundamental magnetic circuit.
  • a plate-shaped permanent magnet 5 has N and S poles disposed at opposite edges.
  • a region E2 of approximate unidirectional magnetic field is available above (or below) one major surface of the plate-shaped permanent magnet 5 as seen from FIG. 13.
  • the magnetic circuit can be located only below (or above) the boundary line F2 of the approximate unidirectional magnetic field region E2.
  • FIG. 14 shows the distribution of lines of magnetic force generated in the second prior art circuit of FIGS. 12 and 13.
  • the plate-shaped permanent magnet 5 is a ferrite permanent magnet having a lateral dimension Lx of 250 mm, a transverse dimension Ly of 300 mm and a thickness Lz of 24 mm.
  • an object of the present invention is to provide a permanent magnet magnetic circuit capable of producing a unidirectional magnetic field free of perpendicular components and of a simple structure which does not surround the unidirectional magnetic field producing region.
  • the permanent magnet magnetic circuit includes a magnet block having a pair of opposite edge surfaces and a pair of major surfaces between the opposite edge surfaces.
  • a pair of main magnetic poles of opposite polarities are situated at the opposite edge surfaces.
  • a channel is defined in one major surface.
  • a pair of auxiliary magnetic poles are situated at a pair of opposed inner surface portions of the channel disposed inside the main magnetic poles. Each auxiliary magnetic pole has opposite polarity to that of the corresponding main magnetic pole.
  • the channel may be recessed stepwise or continuously to define the opposed inner surface portions.
  • the permanent magnet magnetic circuit includes a magnet block having a pair of opposite edge surfaces, with a magnetic pole of one polarity at one edge surface and a magnetic pole of opposite polarity at the other edge surface for creating a magnetic field having lines of magnetic force extending from the one edge surface to the other edge surface. Compensating magnetic poles are situated between the edge surfaces for controlling the vectorial direction of the magnetic field.
  • the permanent magnet magnetic circuit includes a magnet block having a pair of opposite edge surfaces.
  • Main magnetic means is provided for creating a loop pattern of lines of magnetic force extending from the one edge surface to the other edge surface.
  • Compensating magnetic means is provided for controlling a middle portion of the lines of magnetic force to be linear.
  • the main magnetic means is comprised of a magnetic pole of one polarity at one edge surface and a magnetic pole of opposite polarity at the other edge surface, and the compensating magnetic means is comprised of auxiliary magnetic poles.
  • a vertical component contained in the magnetic field produced between the main magnetic poles can be offset by a vertical component of opposite orientation contained in the magnetic field produced between the main and auxiliary (or compensating) magnetic poles.
  • the unidirectional magnetic field region is spaced from the magnet block so that the magnetic circuit does not surround the unidirectional magnetic field region. The circuit is thus best suited as the unidirectional magnetic field producing means associated with semiconductor manufacturing apparatus.
  • the circuit include a rectangular magnet block 20 of a suitable permanent magnet material such as ferrite or rare earth permanent magnet.
  • the block 20 has a pair of first and second opposite edge or outer surfaces and a pair of major surfaces joining the first and second opposite edge surfaces and extending substantially perpendicular to the edge surfaces.
  • Main magnetic poles 21A and 21B are formed in the first and second opposite edge surfaces by magnetization.
  • the main magnetic poles 21 A and 21 B are N and S poles, respectively.
  • a channel 22 is defined in one (upper in the illustrated embodiment) major surface.
  • the channel 22 illustrated herein is a transverse trough extending throughout the block 20 in a transverse direction and recessed stepwise at the right and left sides in a symmetrical manner as viewed in the front elevation of FIG. 2.
  • a flat bottom is connected to the stepwise side walls.
  • the channel includes at least one pair, three pairs in the illustrated embodiment, of steps defining opposed inner surface portions disposed inward of the opposite edge surfaces (21A, 21B).
  • Auxiliary magnetic poles in the form of compensating magnetic poles 23Ai, 23A 2 and 23A3 are formed by magnetization in the inner surface portions on the left side disposed inward of the main magnetic pole 21A.
  • auxiliary magnetic poles in the form of compensating magnetic poles 23B i , 23B 2 and 23B 3 are formed by magnetization in the inner surface portions on the right side disposed inward of the main magnetic pole 21 B.
  • the auxiliary magnetic poles have opposite polarity to that of the main magnetic poles.
  • the compensating magnetic poles 23Ai, 23A 2 and 23A3 are S poles and the compensating magnetic poles 23B i , 23B 2 and 23B 3 are N poles.
  • the main and auxiliary magnetic poles 21 and 23 have equal surface magnetic flux density, but the main magnetic poles have a substantially larger total quantity of magnetic flux.
  • the compensating magnetic poles 23 function to compensate for magnetic force for tailoring the lines of magnetic force produced by the main magnetic poles 21 to be linear.
  • FIG. 3 shows the distribution of lines of magnetic force generated in the magnetic circuit embodiment of FIGS. 1 and 2.
  • FIG. 4 is an enlarged view of a portion of FIG. 3.
  • the magnet block 20 is a ferrite permanent magnet having a lateral dimension Lx of 250 mm, a transverse dimension Ly of 300 mm and a thickness Lz of 60 mm and the channel 22 defined therein includes three pairs of opposed steps each having a lateral width of 20 mm and a height of 10 mm.
  • the first embodiment of FIGS. 1 and 2 produces a magnetic field whose unnecessary vertical component Bz is substantially equal to zero over a substantial portion of the X range.
  • the magnetic field has a vector V1 directing from the main N pole toward the main S pole and a vector V2 extending between each main magnetic pole (N or S pole) and each compensating magnetic pole (S or N pole).
  • the magnetic poles are arranged such that the resultant magnetic field vector VO may become substantially horizontal.
  • the first embodiment of FIGS. 1 and 2 produces a nearly ideal unidirectional magnetic field substantially free of unnecessary perpendicular components over a wide range.
  • the magnetic circuit may be located on one side of the unidirectional magnetic field region because the magnetic circuit does not enclose the unidirectional magnetic field.
  • FIGS. 7 and 8 show a second embodiment of the present invention.
  • This embodiment is similar to the first embodiment except the channel geometry.
  • the magnet block 20 includes a continuously or smoothly recessed channel 30 in one major surface between the opposite edge surfaces.
  • the continuous channel used herein means that the opposed inner side walls are curvilinear or rectilinear slant walls joining to a flat bottom.
  • the inner side walls are symmetrical as viewed in the elevation of FIG. 8.
  • Compensating magnetic poles 23A and 23B are formed by magnetization in the opposed inner side walls disposed inward of the main magnetic poles 21A and 21B, respectively.
  • the main magnetic poles 21A and 21 B are N and S
  • the compensating magnetic poles 23A and 23B are S and N, respectively.
  • the magnet block 20 is a ferrite permanent magnet having a lateral dimension Lx of 250 mm, a transverse dimension Ly of 300 mm and a thickness Lz of 60 mm and the channel 30 defined therein includes a flat bottom having a lateral dimension of 130 mm and a thickness of 30 mm.
  • the magnetic poles are arranged such that the resultant magnetic field vector VO between a vector V1 directing from the main N pole toward the main S pole and a vector V2 directing from each main magnetic pole (N or S pole) toward each compensating magnetic pole (S or N pole) in the region where a unidirectional magnetic field is to be produced as shown in FIG. 5 becomes substantially horizontal.
  • FIGS. 9 and 10 show a third embodiment of the present invention.
  • This embodiment is similar to the first embodiment except the block geometry.
  • a disk-shaped magnet block 40 having a pair of opposite edge surface segments, that is, arcuate segments included within angles 81 and 02 where main magnetic poles 41A and 41B are formed by magnetization.
  • the main magnetic poles 41A and 41B are N and S poles, respectively, in the illustrated embodiment.
  • the magnet block 40 has a pair of major surfaces joining the opposite edge surface segments (41A and 41 B) and extending substantially perpendicular to the segments (in the cross section of FIG. 10).
  • a transverse channel 42 is defined in one major surface.
  • the channel 42 has symmetric steps defining pairs of opposed inner surface portions disposed inward of the opposite edge surface segments.
  • compensating magnetic poles 43Bi, 43B 2 and 43B 3 of opposite polarity by magnetization in the opposed inner surface portions disposed inward of the main magnetic pole 41B of one polarity are formed compensating magnetic poles 43Bi, 43B 2 and 43B 3 of opposite polarity by magnetization.
  • compensating magnetic poles of one polarity in the opposed inner surface portions disposed inward of the main magnetic pole 41A of opposite polarity are formed compensating magnetic poles of one polarity.
  • the magnet block may be either a unitary permanent magnet block or an assembly of a plurality of permanent magnet pieces.
  • the magnetic circuit is advantageously applicable to semiconductor fabricating apparatus and similar apparatus where restrictions are imposed on the attachment or location of the circuit.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
  • Magnetic Treatment Devices (AREA)
EP91115830A 1990-09-19 1991-09-18 Magnetkreis mit Permanentmagnet Expired - Lifetime EP0476609B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP249040/90 1990-09-19
JP2249040A JP2826895B2 (ja) 1990-09-19 1990-09-19 永久磁石磁気回路

Publications (3)

Publication Number Publication Date
EP0476609A2 true EP0476609A2 (de) 1992-03-25
EP0476609A3 EP0476609A3 (en) 1992-11-19
EP0476609B1 EP0476609B1 (de) 1995-10-11

Family

ID=17187112

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91115830A Expired - Lifetime EP0476609B1 (de) 1990-09-19 1991-09-18 Magnetkreis mit Permanentmagnet

Country Status (4)

Country Link
EP (1) EP0476609B1 (de)
JP (1) JP2826895B2 (de)
KR (1) KR100201575B1 (de)
DE (1) DE69113732T2 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0656621A2 (de) * 1993-12-03 1995-06-07 Eastman Kodak Company Magnetoresistiver Kopf mit abgeschiedenem Vormagnetisierungsmagnet
CN102723164A (zh) * 2012-06-04 2012-10-10 江苏多维科技有限公司 一种凹槽形永磁体及包括该永磁体的磁传感器
CN104835614A (zh) * 2015-05-29 2015-08-12 李丽霞 一种复合式磁铁及包括该复合式磁铁的磁传感器

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3065781B2 (ja) * 1992-03-09 2000-07-17 ティーディーケイ株式会社 永久磁石磁気回路
KR100334670B1 (ko) * 1994-06-21 2002-11-22 삼성전기주식회사 편향요크의그린빔드롭현상방지장치
JP4627921B2 (ja) * 2001-05-08 2011-02-09 信越化学工業株式会社 永久磁石の磁気回路

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3237059A (en) * 1962-10-04 1966-02-22 Siemens Ag Permanent magnet system for producing a magnetic field for the focused passage of a beam of electrons
JPS59208812A (ja) * 1983-05-13 1984-11-27 Mitsubishi Electric Corp 高均一磁場発生装置
JPS6075589A (ja) * 1983-09-30 1985-04-27 Toshiba Corp ドライエツチング装置
JPS647156A (en) * 1987-06-30 1989-01-11 Nec Corp Processing system for reception data
DE3832835A1 (de) * 1988-09-28 1990-03-29 Windhorst Beteiligungsgesellsc Dauermagnetanordnung zum magnetischen entsperren der sperrvorrichtungen von warensicherungssystemen
JPH02117106A (ja) * 1988-10-27 1990-05-01 Shin Etsu Chem Co Ltd 磁場発生装置
WO1990007774A1 (en) * 1989-01-03 1990-07-12 Eastman Kodak Company Deposited permanent magnet for hard and easy axes biasing of a magnetoresistive head

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3237059A (en) * 1962-10-04 1966-02-22 Siemens Ag Permanent magnet system for producing a magnetic field for the focused passage of a beam of electrons
JPS59208812A (ja) * 1983-05-13 1984-11-27 Mitsubishi Electric Corp 高均一磁場発生装置
JPS6075589A (ja) * 1983-09-30 1985-04-27 Toshiba Corp ドライエツチング装置
JPS647156A (en) * 1987-06-30 1989-01-11 Nec Corp Processing system for reception data
DE3832835A1 (de) * 1988-09-28 1990-03-29 Windhorst Beteiligungsgesellsc Dauermagnetanordnung zum magnetischen entsperren der sperrvorrichtungen von warensicherungssystemen
JPH02117106A (ja) * 1988-10-27 1990-05-01 Shin Etsu Chem Co Ltd 磁場発生装置
WO1990007774A1 (en) * 1989-01-03 1990-07-12 Eastman Kodak Company Deposited permanent magnet for hard and easy axes biasing of a magnetoresistive head

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
IBM TECHNICAL DISCLOSURE BULLETIN vol. 19, no. 5, October 1976, NEW YORK pages 1856 - 1857; JONES ET AL: 'directionally homogeneous magnets for vacuum-deposition apparatus' *
PATENT ABSTRACTS OF JAPAN vol. 14, no. 344 (E-955)(4287) 25 July 1990 & JP-A-2 117 106 ( SHIN ETSU CHEM ) 1 May 1990 *
PATENT ABSTRACTS OF JAPAN vol. 9, no. 69 (E-305)(1792) 29 March 1985 & JP-A-59 208 812 ( MITSUBISHI DENKI ) 27 November 1984 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0656621A2 (de) * 1993-12-03 1995-06-07 Eastman Kodak Company Magnetoresistiver Kopf mit abgeschiedenem Vormagnetisierungsmagnet
EP0656621A3 (de) * 1993-12-03 1996-07-31 Eastman Kodak Co Magnetoresistiver Kopf mit abgeschiedenem Vormagnetisierungsmagnet.
CN102723164A (zh) * 2012-06-04 2012-10-10 江苏多维科技有限公司 一种凹槽形永磁体及包括该永磁体的磁传感器
CN104835614A (zh) * 2015-05-29 2015-08-12 李丽霞 一种复合式磁铁及包括该复合式磁铁的磁传感器

Also Published As

Publication number Publication date
JPH04127504A (ja) 1992-04-28
KR100201575B1 (ko) 1999-06-15
EP0476609B1 (de) 1995-10-11
DE69113732T2 (de) 1996-05-30
JP2826895B2 (ja) 1998-11-18
KR920007011A (ko) 1992-04-28
EP0476609A3 (en) 1992-11-19
DE69113732D1 (de) 1995-11-16

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