JP3406273B2 - Disturbance magnetic field cancellation device - Google Patents
Disturbance magnetic field cancellation deviceInfo
- Publication number
- JP3406273B2 JP3406273B2 JP2000089476A JP2000089476A JP3406273B2 JP 3406273 B2 JP3406273 B2 JP 3406273B2 JP 2000089476 A JP2000089476 A JP 2000089476A JP 2000089476 A JP2000089476 A JP 2000089476A JP 3406273 B2 JP3406273 B2 JP 3406273B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- canceling
- coil
- disturbance
- local
- 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 - Fee Related
Links
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、分析装置等が外部
からの変動磁界による悪影響を受けないように、その使
用場所において変動磁界をキャンセルするための装置に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for canceling a fluctuating magnetic field at the place of use so that an analyzer or the like is not adversely affected by a fluctuating magnetic field from the outside.
【０００２】[0002]
【従来の技術】走査電子顕微鏡などが配置されている場
所の周辺には、車輌やエレベーター等の移動に伴う変動
磁界や配電線から生じる交流磁界など、その分析性能を
劣化させるような変動磁界の発生源が多く存在する。こ
の様な変動磁界による悪影響をなるべく少なくするた
め、従来から磁気シールドルームや外乱磁界をキャンセ
ルする装置が実用化されている。従来の外乱磁界キャン
セル装置では、図４に示すように、磁界検出器５１、増
幅器５２、減算回路５３、電流出力回路５４、外乱磁界
の打ち消し磁界用コイル５５により構成されており、走
査電子顕微鏡筒など分析装置５６の周りを前記外乱磁界
打ち消し磁界用コイル５５で囲って磁界キャンセルの領
域が形成されている。そして、その磁界キャンセル領域
内部であって分析装置５６の近傍に前記磁界検出器５１
を設置して使用されているのである。図中５７は前述し
た外乱磁界の発生源を示している。上記装置において
は、外乱磁界の発生源５７で生じた磁界は磁界検出器５
１で検知され、この磁気検知信号は増幅器５２で増幅さ
れた後、減算回路５３で地磁気等の静磁界が減算され
る。そして、それにより算出された磁界変動分が、電流
出力回路５４により外乱磁界の打ち消し磁界用コイル５
５を励磁する。磁界検出器５１の検知信号が０となるよ
うにフィードバック制御を行うように出力され、これに
より前記外乱磁界を打ち消すようになっている。2. Description of the Related Art Around a place where a scanning electron microscope or the like is placed, there is a fluctuation magnetic field that causes deterioration of analysis performance such as a fluctuation magnetic field due to movement of a vehicle or an elevator or an AC magnetic field generated from a distribution line. There are many sources. In order to reduce the adverse effects of such a fluctuating magnetic field as much as possible, a magnetic shield room and a device for canceling a disturbance magnetic field have been put into practical use. As shown in FIG. 4, the conventional disturbance magnetic field canceling device is composed of a magnetic field detector 51, an amplifier 52, a subtraction circuit 53, a current output circuit 54, and a disturbance magnetic field canceling magnetic field coil 55. A magnetic field canceling region is formed by surrounding the analyzer 56 with the disturbance magnetic field canceling magnetic field coil 55. The magnetic field detector 51 is provided inside the magnetic field canceling region and near the analyzer 56.
Is installed and used. In the figure, reference numeral 57 indicates the source of the above-mentioned disturbance magnetic field. In the above device, the magnetic field generated by the disturbance magnetic field source 57 is generated by the magnetic field detector 5
1, the magnetic detection signal is amplified by an amplifier 52, and then a subtraction circuit 53 subtracts a static magnetic field such as geomagnetism. Then, the magnetic field fluctuation amount calculated thereby is canceled by the current output circuit 54 to the disturbance magnetic field coil 5
Excite 5 The detection signal of the magnetic field detector 51 is outputted so as to perform feedback control so that it becomes 0, thereby canceling the disturbance magnetic field.
【０００３】[0003]
【発明が解決しようとする課題】ところで、前記外乱磁
界キャンセル装置にあっては、外乱磁界を打ち消すコイ
ルを円形コイルとし、コイル間隔を半径とする理想的ヘ
ルムホルツコイルにすると、走査電子顕微鏡筒などの分
析装置５６のスペース確保が狭くなって困難となる。し
かし、スペース確保のために、前記打ち消し磁界用コイ
ル５５の一方５５ａ，他方５５ｂのコイル間隔を拡張し
なければならない。その結果として発生磁界の勾配がで
きる範囲が広くなり、均一性に欠けることになる。ま
た、打ち消し磁界用コイル５５を小さくすると変動磁界
キャンセル領域は狭くなり、打ち消し磁界用コイル５５
を大きくするとコイル周辺にある他の装置に乱磁界を発
生することになる。By the way, in the disturbance magnetic field canceling apparatus, when the coil for canceling the disturbance magnetic field is a circular coil and the ideal Helmholtz coil having a coil interval is a radius, a scanning electron microscope tube or the like is used. It becomes difficult to secure a space for the analyzer 56, which is difficult. However, in order to secure a space, the coil spacing between the one 55a and the other 55b of the canceling magnetic field coil 55 must be expanded. As a result, the range in which the gradient of the generated magnetic field can be widened becomes wide and lacks uniformity. If the canceling magnetic field coil 55 is made smaller, the variable magnetic field canceling region becomes narrower, and the canceling magnetic field coil 55 becomes smaller.
When is increased, a turbulent magnetic field is generated in another device around the coil.
【０００４】ここで、磁界キャンセル装置で使用される
コイル形状は正方形が一般的であり、単独の正方形コイ
ルの中心から面に垂直に、Ｄの距離における磁界は、正
方形コイルの一辺を２Ｌ、巻線数をＮ、流す電流をＩと
すれば、次式で表される。
Ｈ＝２ＩＬ2 Ｎ／（π（Ｌ2 ＋Ｄ2 ）（２Ｌ2 ＋Ｄ2 ）1/2 ）・・（１）
（１）式から、コイルからの距離により磁界の強さ一様
ではなく、減衰していくことが分かる。図５は、対向す
る一対の打ち消し用コイルにおける磁界の強度分布を、
（１）式を基にしてグラフ化したものであって、横軸に
距離、縦軸に磁界の強さを示す。 図中の５５ａｘ，５
５ｂｘは対向する単独の打ち消し用コイルによる各打ち
消し磁界、５５ｃは打ち消し合成磁界、５７ａは外乱磁
界で理解し易いように極性を反転（負）して表示してい
る。図から磁界検出器５１の位置では、合成磁界の強さ
と外乱磁界が一致しているので外乱磁界５７ａは相殺で
きているが、分析装置５６などを置くコイル中央部の最
も重要な位置では、合成磁界５５ｃと外乱磁界５７ａと
の間に差が生じており、外乱磁界が完全に打ち消されて
いないことが分かる。Here, the coil shape used in the magnetic field canceling device is generally square, and the magnetic field at a distance D perpendicular to the plane from the center of a single square coil is wound by 2 L on one side of the square coil. Assuming that the number of wires is N and the flowing current is I, it is expressed by the following equation. H = 2IL2 N / (π (L2 + D2) (2L2 + D2) 1/2) ・ (1) From the equation (1), the magnetic field strength may not be uniform but may be attenuated depending on the distance from the coil. I understand. FIG. 5 shows the intensity distribution of the magnetic field in the pair of opposing canceling coils,
It is a graph based on the equation (1), in which the horizontal axis represents distance and the vertical axis represents magnetic field strength. 55ax, 5 in the figure
5bx is each canceling magnetic field by a single opposing canceling coil, 55c is a canceling combined magnetic field, and 57a is a disturbance magnetic field, and its polarity is inverted (negative) for easy understanding. From the figure, at the position of the magnetic field detector 51, since the strength of the synthetic magnetic field and the disturbance magnetic field coincide with each other, the disturbance magnetic field 57a can be canceled, but at the most important position of the coil center where the analyzer 56 and the like are placed, It can be seen that there is a difference between the magnetic field 55c and the disturbance magnetic field 57a, and the disturbance magnetic field is not completely canceled.
【０００５】従来の外乱磁界キャンセル装置ではこのよ
うな欠点があって、磁界検出器５１と分析装置５６との
距離が離れるほど打ち消し誤差は増大し、走査電子顕微
鏡などの装置を使用して精確な分析はできないという問
題があった。The conventional disturbance magnetic field canceling device has such drawbacks, and the canceling error increases as the distance between the magnetic field detector 51 and the analyzing device 56 increases, and it is accurate using a device such as a scanning electron microscope. There was a problem that analysis was not possible.
【０００６】本発明はこのような従来の問題点を解決す
るもので、磁界検出器を走査電子顕微鏡筒など装置の重
要な中心に置くことができない場合でも外乱磁界を打ち
消し精確な分析ができ、さらに打ち消すコイルを最小限
に設置できる外乱磁界キャンセル装置を提供することを
目的とする。The present invention solves the above-mentioned conventional problems. Even when the magnetic field detector cannot be placed at an important center of the apparatus such as a scanning electron microscope cylinder, the disturbance magnetic field can be canceled and accurate analysis can be performed. Further, it is an object of the present invention to provide a disturbance magnetic field canceling device in which a coil for canceling can be installed to a minimum.
【０００７】[0007]
【課題を解決するための手段】前記目的を達成するため
の手段として、本発明請求項１記載の外乱磁界キャンセ
ル装置では、外乱磁界を打ち消す磁界を発生するための
コイルを備えた外乱磁界キャンセル装置において、前記
外乱磁界の打ち消し磁界用コイル近傍であって該コイル
における磁束通過面の一部において前記磁束通過面の法
線方向と同一方向の磁界をキャンセルする局部磁界打ち
消しコイルと、前記局部磁界打ち消しコイルの磁束通過
領域内に配置される前記外乱磁界を検知する磁界検出器
と、前記磁界検出器の検知信号により前記外乱磁界の打
ち消し磁界用コイルと前記局部磁界打ち消しコイルに外
乱磁界キャンセル用電流を出力する電流出力回路と、を
有することを特徴とする。As means for achieving the above object, in a disturbance magnetic field canceling device according to claim 1 of the present invention, a disturbance magnetic field canceling device comprising a coil for generating a magnetic field for canceling the disturbance magnetic field. in, a near field coil cancellation of the disturbance magnetic field the coil
Of a part of the magnetic flux passage surface in
A local magnetic field canceling coil for canceling a magnetic field in the same direction as the line direction, a magnetic field detector for detecting the disturbance magnetic field arranged in the magnetic flux passing region of the local magnetic field canceling coil, and the detection signal of the magnetic field detector It has a coil for canceling a disturbance magnetic field and a current output circuit for outputting a current for canceling a disturbance magnetic field to the local magnetic field canceling coil.
【０００８】請求項２記載の外乱磁界キャンセル装置で
は、請求項１記載の外乱磁界キャンセル装置において、
局部磁界打ち消しコイルを備えた外乱磁界の打ち消し磁
界用コイルが互いに直交する３軸の位置ごとに対を成し
て対向配置されていることを特徴とする。A disturbance magnetic field canceling device according to a second aspect is the disturbance magnetic field canceling device according to the first aspect.
It is characterized in that the disturbance magnetic field canceling magnetic field coils having the local magnetic field canceling coils are arranged so as to face each other in pairs at three mutually orthogonal positions.
【０００９】請求項３記載の外乱磁界キャンセル装置で
は、請求項１または請求項２記載の外乱磁界キャンセル
装置において、局部磁界打ち消しコイルが外乱磁界の打
ち消し磁界用コイルの面内に配置され、磁界検出器が局
部磁界打ち消しコイルの磁束中心位置に配置されている
ことを特徴とする。In the disturbance magnetic field canceling device according to a third aspect of the present invention, in the disturbance magnetic field canceling device according to the first or second aspect, the local magnetic field canceling coil is arranged in the plane of the canceling magnetic field canceling magnetic field coil to detect the magnetic field. Is placed at the center of the magnetic flux of the local magnetic field canceling coil.
【００１０】請求項４記載の外乱磁界キャンセル装置で
は、外乱磁界を検知する磁界検出器と、この磁界検出器
と対を成して配置され外乱磁界を打ち消す磁界を発生さ
せるための打ち消し磁界用コイルと、前記磁界検出器の
位置に前記打ち消し磁界用コイルの発生磁界の影響を一
部分キャンセルして補正する磁界を発生する局部磁界打
ち消しコイルと、前記磁界検出器よりの出力信号が供給
される増幅器と、前記増幅器の信号から静磁界成分を減
算し変動磁界成分を出力する回路と、変動磁界成分を励
磁電流として出力する電流出力回路と、前記電流出力を
打ち消し磁界用コイルと局部磁界打ち消しコイルとに分
流する分流器を備え、外乱磁界の打ち消し磁界用コイル
と局部磁界打ち消しコイルは前記電流出力回路の出力に
基づいて励磁されるように構成されていることを特徴と
する。[0010] In magnetic disturbance cancellation device according to claim 4 is a magnetic field detector for detecting a magnetic disturbance, striking Chi erase magnetic field for generating a magnetic field that cancels the are arranged in the magnetic field detector paired magnetic disturbance and use the coil, the magnetic field detector
A local magnetic field canceling coil that generates a magnetic field that partially cancels and corrects the effect of the magnetic field generated by the canceling magnetic field coil at a position, an amplifier to which an output signal from the magnetic field detector is supplied, and a static signal from the amplifier signal. A circuit for subtracting a magnetic field component to output a fluctuating magnetic field component, a current output circuit for outputting a fluctuating magnetic field component as an exciting current, and a shunt for shunting the current output to a magnetic field canceling coil and a local magnetic field canceling coil, The disturbance magnetic field canceling magnetic field coil and the local magnetic field canceling coil are configured to be excited based on the output of the current output circuit.
【００１１】[0011]
【作用】本発明の外乱磁界キャンセル装置では、外乱磁
界を検出する磁界検出器を外乱磁界の打ち消し磁界用コ
イル近傍であって磁束通過領域の一部において磁界をキ
ャンセルする局部磁界打ち消しコイルの磁束通過領域内
に配置したので、磁界検出器は静磁界成分と変動磁界成
分を検出する。そこで検出信号成分から変動磁界成分だ
けを抽出し、その値を基にしてリアルタイムで打ち消し
磁界用電流と磁界レベル補正のための局部磁界打ち消し
用電流を各コイルに流すことにより、判定装置などが設
置される真に必要な位置での外乱磁界を良好にキャンセ
ルし、走査電子顕微鏡筒などによる判定を極めて精確に
行うことができるようになる。また、余分に強力なキャ
ンセル用磁界を必要としないので、外乱磁界の打ち消し
磁界用コイルを小型化でき、使用場所や装置の大きさ等
に限定されることなく使用することができる。According to the disturbance magnetic field canceling apparatus of the present invention, the magnetic field detector for detecting the disturbance magnetic field passes the magnetic flux of the local magnetic field canceling coil for canceling the magnetic field in a part of the magnetic flux passing region in the vicinity of the coil for canceling the disturbing magnetic field. Since it is arranged in the area, the magnetic field detector detects the static magnetic field component and the fluctuating magnetic field component. Therefore, only the fluctuating magnetic field component is extracted from the detection signal component, and based on the value, the current for magnetic field for canceling and the current for local magnetic field for correcting the magnetic field level are supplied to each coil in real time, so that the judgment device is installed. It is possible to satisfactorily cancel the disturbance magnetic field at the truly required position, and it is possible to make an extremely accurate determination by the scanning electron microscope cylinder or the like. Further, since an extra strong canceling magnetic field is not required, the disturbance magnetic field canceling magnetic field coil can be miniaturized and can be used regardless of the place of use or the size of the device.
【００１２】[0012]
【発明の実施の形態】以下、本発明の実施の形態を図面
に基づいて詳細に説明する。図１は実施の形態の外乱磁
界キャンセル装置を示す模式図、図２は同上の使用状態
を示す斜視図、図３は同上の装置内発生磁界を示すグラ
フ図である。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram showing a disturbance magnetic field canceling device of an embodiment, FIG. 2 is a perspective view showing a usage state of the same, and FIG. 3 is a graph showing a magnetic field generated inside the device of the same.
【００１３】まず、実施の形態の構成を説明する。本実
施の形態の外乱磁界キャンセル装置は、磁界検出器ｘ
１，ｙ１，ｚ１、増幅器ｘ２，ｙ２，ｚ２、減算回路ｘ
３，ｙ３，ｚ３、電流出力回路ｘ４，ｙ４，ｚ４、分流
器ｘ５，ｙ５，ｚ５、外乱磁界の打ち消し磁界用コイル
ｘ６，ｙ６，ｚ６、局部磁界打ち消しコイルｘ７，ｙ
７，ｚ７を主要な構成としている。図中８は外乱磁界発
生源、９は走査電子顕微鏡筒などの判定装置である。First, the configuration of the embodiment will be described. The disturbance magnetic field canceling device according to the present embodiment includes a magnetic field detector x
1, y1, z1, amplifiers x2, y2, z2, subtraction circuit x
3, y3, z3, current output circuits x4, y4, z4, shunts x5, y5, z5, disturbance magnetic field canceling magnetic field coils x6, y6, z6, local magnetic field canceling coils x7, y
7 and z7 are the main components. In the figure, 8 is a disturbance magnetic field generation source, and 9 is a determination device such as a scanning electron microscope cylinder.
【００１４】前記磁界検出器ｘ１は従来と同様に、ホー
ル素子や磁気抵抗素子等の磁界を検知する素子やフラッ
クスゲートセンサのような磁気検知回路を使用してお
り、外乱発生源８で発生した変動磁界を検知するもので
ある。増幅器ｘ２は、磁界検出器ｘ１の検知信号を増幅
するものであり、減算回路ｘ３は、増幅器ｘ２の出力か
ら地磁気等の静磁界成分を減算し変動磁界成分を算出す
るものである。電流出力回路ｘ４は、前記変動磁界成分
のみに比例した電流出力を行うものであり、分流器ｘ５
は、前記出力電流を外乱磁界の打ち消し磁界用コイルｘ
６と磁界レベル補正のための局部磁界打ち消しコイルｘ
７に分流するものである。外乱磁界の打ち消し磁界用コ
イルｘ６，ｙ６，ｚ６は、前記判定装置９を囲繞するよ
うにそれぞれ三軸上に一対づつ対向配置され、内部に磁
界キャンセルの領域を形成するものである。局部磁界打
ち消しコイルｘ７〜ｚ７は、それぞれ前記外乱磁界の打
ち消し磁界用コイルｘ６〜ｚ６の面内中心位置に配置さ
れ、更に、それぞれその中心位置に、前記磁界検出器ｘ
１〜ｚ１を配置させるものである。尚、ｙ２〜ｙ５，ｚ
２〜ｚ５も前記と同様の構成であるので、その説明は省
略する。As in the conventional case, the magnetic field detector x1 uses an element for detecting a magnetic field, such as a Hall element or a magnetoresistive element, or a magnetic detection circuit such as a fluxgate sensor. It detects a fluctuating magnetic field. The amplifier x2 amplifies the detection signal of the magnetic field detector x1, and the subtraction circuit x3 subtracts a static magnetic field component such as geomagnetism from the output of the amplifier x2 to calculate a fluctuating magnetic field component. The current output circuit x4 outputs a current proportional to only the fluctuating magnetic field component, and the shunt x5
Is a coil x for magnetic field for canceling the disturbance current of the output current.
6 and local magnetic field cancellation coil x for magnetic field level correction
It is divided into seven. The disturbance magnetic field canceling magnetic field coils x6, y6, z6 are arranged in pairs so as to surround the determination device 9 in pairs on three axes and form a magnetic field canceling region inside. The local magnetic field canceling coils x7 to z7 are arranged at in-plane center positions of the disturbance magnetic field canceling magnetic field coils x6 to z6, respectively, and further, the magnetic field detector x is located at the center position.
1 to z1 are arranged. In addition, y2-y5, z
2 to z5 also have the same configuration as described above, and thus the description thereof will be omitted.
【００１５】次に作用を説明する。磁界検出器ｘ１によ
り、外乱発生源８で発生した変動磁界成分の磁界を検出
し電流出力回路ｘ４で励磁電流として発生させるのだ
が、従来装置との違いはここから生じてくる。まず、図
３は、本発明装置内で発生する磁界の強さを横軸に距離
を取って表示したものである。図中のｘ６ａ，ｘ６ｂ
は、（１）式に基づいて発生する外乱磁界の打ち消し磁
界用コイルｘ６の一方６ａと他方６ｂによる磁界を示
す。また、ａ１は前記磁界ｘ６ａ，ｘ６ｂによるキャン
セル用合成磁界、ｂ１は外乱磁界である。ｃ１は局部磁
界打ち消しコイル７の局部キャンセル用磁界、ｄ１はキ
ャンセル用合成磁界ａ１と逆極性の局部キャンセル用磁
界ｃ１の合成磁界を示す。Next, the operation will be described. Although the magnetic field of the fluctuating magnetic field component generated in the disturbance generation source 8 is detected by the magnetic field detector x1 and generated as the exciting current in the current output circuit x4, the difference from the conventional device arises from this. First, FIG. 3 shows the strength of the magnetic field generated in the device of the present invention with the horizontal axis taken as a distance. X6a and x6b in the figure
Indicates a magnetic field generated by the one side 6a and the other side 6b of the canceling magnetic field coil x6 of the disturbance magnetic field generated based on the equation (1). Further, a1 is a canceling synthetic magnetic field by the magnetic fields x6a and x6b, and b1 is a disturbance magnetic field. c1 represents a local canceling magnetic field of the local magnetic field canceling coil 7, and d1 represents a synthetic magnetic field of a local canceling magnetic field c1 having a polarity opposite to that of the canceling synthetic magnetic field a1.
【００１６】図のｃ１は、円形コイルの中心に磁界検出
器ｘ１を配置した事例であって、次式（２）に基づいて
発生する磁界であって、コイル径が小さいと、磁界の強
さはコイルから離れるに従い急激に減少するので、局部
キャンセル用磁界ｃ１の影響は外乱磁界の打ち消し磁界
用コイルｘ６の一方６ａと他方６ｂとの中央部まで及ば
ない。
Ｈ＝ｒ2 ・Ｎ・Ｉ／２（ｒ2 ＋Ｄ2 ）3/2 ・・・（２）
ただし、ｒはコイルの径、Ｎは巻数、Ｉは電流、Ｄはコ
イルの中心から面に垂直に離れた距離である。そこで、
磁界検出器ｘ１が設置されているコイル位置Ａ点におい
て、打ち消し磁界用コイルｘ６が発生する磁界ｘ６ａ，
ｘ６ｂの合成磁界ａ１を打ち消すように、局部磁界打ち
消しコイルｘ７に電流を流せば、コイル位置近傍におけ
る磁界の強度分布は曲線ｄ１となり、Ａ点では打ち消し
磁界用コイルｘ６が発生する磁界の影響を受けなくな
り、外乱磁界キャンセル性能は著しく改善される。In the figure, c1 is an example in which the magnetic field detector x1 is arranged at the center of the circular coil, which is a magnetic field generated based on the following equation (2). When the coil diameter is small, the magnetic field strength is high. Is drastically reduced as the distance from the coil is increased, so that the effect of the local canceling magnetic field c1 does not extend to the central portion between the one side 6a and the other side 6b of the disturbance magnetic field canceling magnetic field coil x6. H = r2.N.I / 2 (r2 + D2) 3/2 (2) where r is the diameter of the coil, N is the number of turns, I is the current, and D is perpendicular to the plane from the center of the coil. It is a distance. Therefore,
At the coil position A where the magnetic field detector x1 is installed, the magnetic field x6a generated by the canceling magnetic field coil x6,
If a current is applied to the local magnetic field canceling coil x7 so as to cancel the combined magnetic field a1 of x6b, the intensity distribution of the magnetic field in the vicinity of the coil position becomes a curve d1, and at point A, the magnetic field generated by the canceling magnetic field coil x6 is affected. The disturbance magnetic field canceling performance is remarkably improved.
【００１７】具体的にはそのために、外乱磁界の打ち消
し磁界用コイルｘ６に流す電流出力回路４の励磁電流
を、分流器ｘ５で局部磁界打ち消しコイルｘ７に分流
し、相互のコイルに同様な比率で励磁電流を流す。その
結果、変動する外乱磁界は打ち消し磁界用コイルｘ６が
発生する磁界でキャンセルすると同時に、Ａ点にその影
響が現れなくする。結局のところ、磁界検出器ｘ１は、
外乱磁界の打ち消し磁界用コイルで発生した磁界に影響
されることなく、外乱磁界の静磁界成分と変動磁界成分
を検出し、その検出信号を増幅器ｘ２で増幅し、減算回
路ｘ３で静磁界成分を減算し、電流出力回路ｘ４から変
動分だけの出力電流を分流器ｘ５を介して局部磁界打ち
消しコイルｘ７と打ち消し磁界用コイルｘ６に分流する
ことにより、外乱磁界を精度良くキャンセルすることが
できるのである。尚、これまでの説明はｘ軸成分にのみ
着目して記載してきたが、ｙ軸成分、ｚ軸成分について
も同様の構成、機能であるので、その説明を省略する。
図中、外乱磁界の打ち消し磁界用コイルｙ６とｚ６につ
いてその一方と他方を区別する符号は省略している。ま
た、各コイルの形状は、正方形、長方形、円形以外にソ
レノイド形状であっても本発明の目的が達成できるもの
であれば、その形状に限定されるものではない。Specifically, for that purpose, the exciting current of the current output circuit 4 which is applied to the external magnetic field canceling magnetic field coil x6 is shunted to the local magnetic field canceling coil x7 by the shunt x5, and the same ratio is applied to the mutual coils. Apply exciting current. As a result, the fluctuating disturbance magnetic field is canceled by the magnetic field generated by the canceling magnetic field coil x6, and at the same time, its influence does not appear at the point A. After all, the magnetic field detector x1
The static magnetic field component and the fluctuating magnetic field component of the disturbance magnetic field are detected without being affected by the magnetic field generated by the canceling magnetic field coil, the detected signal is amplified by the amplifier x2, and the static magnetic field component is detected by the subtraction circuit x3. The disturbance magnetic field can be accurately canceled by subtracting and diverting the output current from the current output circuit x4 into the local magnetic field canceling coil x7 and the canceling magnetic field coil x6 via the shunt x5. . It should be noted that although the description so far has been made by focusing only on the x-axis component, the y-axis component and the z-axis component have similar configurations and functions, and therefore description thereof will be omitted.
In the figure, the reference numerals for distinguishing one of the coils y6 and z6 for canceling the disturbance magnetic field from the other are omitted. Further, the shape of each coil is not limited to a square, a rectangle, a circle, and a solenoid shape as long as the object of the present invention can be achieved.
【００１８】以上、説明してきたように本実施の形態の
外乱磁界キャンセル装置にあっては、磁界検出器１は静
磁界成分と変動磁界成分の磁界検出だけとなるので、変
動磁界成分だけを抽出しその値によってリアルタイムで
各コイルを励磁することにより、真に必要な位置での外
乱磁界を良好にキャンセルし、走査電子顕微鏡筒９など
による判定を極めて精確に行うことができる。また、余
分に強力なキャンセル用磁界を必要としないので、外乱
磁界の打ち消し磁界用コイルを小型化でき、使用場所や
装置の大きさ等に限定されることなく使用することがで
きる。As described above, in the disturbance magnetic field canceling device of the present embodiment, the magnetic field detector 1 only detects the static magnetic field component and the varying magnetic field component, and therefore only the varying magnetic field component is extracted. By exciting each coil in real time by the value, the disturbance magnetic field at the truly required position can be canceled well, and the determination by the scanning electron microscope cylinder 9 or the like can be performed extremely accurately. Further, since an extra strong canceling magnetic field is not required, the disturbance magnetic field canceling magnetic field coil can be miniaturized and can be used regardless of the place of use or the size of the device.
【００１９】以上、本発明の実施の形態を説明してきた
が、本発明の具体的な構成はこの実施の形態に限定され
るものではなく、発明の要旨を逸脱しない範囲の設計変
更等があっても本発明に含まれる。Although the embodiment of the present invention has been described above, the specific configuration of the present invention is not limited to this embodiment, and there are design changes and the like within the scope not departing from the gist of the invention. However, it is included in the present invention.
【００２０】[0020]
【発明の効果】以上、説明してきたように本発明の外乱
磁界キャンセル装置にあっては、前記構成としたため、
打ち消し磁界用コイル間隔内側に磁界検出器を設置しな
いでも要部の外乱磁界を精確に検知することができ、極
めて精確な判定などの作業を行うことができる。また、
打ち消し磁界用コイルを最小限に小さく構成して設置す
ることができる。そのため、外部装置に及ぼす悪影響を
減少させることができる。更に、コイル間隔の内部に磁
界検出器を置く必要がないため、乱磁界発生源を逆に打
ち消し磁界用コイルで囲み、外部装置に及ぼす乱磁界の
悪影響を減少させることもできる。As described above, since the disturbance magnetic field canceling device of the present invention has the above-mentioned structure,
Even if the magnetic field detector is not installed inside the canceling magnetic field coil interval, the disturbance magnetic field of the main part can be accurately detected, and work such as extremely accurate determination can be performed. Also,
The canceling magnetic field coil can be installed with a minimum configuration. Therefore, the adverse effect on the external device can be reduced. Further, since it is not necessary to place the magnetic field detector inside the coil interval, the disturbing magnetic field generation source can be reversed and surrounded by the coil for magnetic field to reduce the adverse effect of the disturbing magnetic field on the external device.
【図１】本発明実施の形態の外乱磁界キャンセル装置を
示す模式図である。FIG. 1 is a schematic diagram showing a disturbance magnetic field canceling device according to an embodiment of the present invention.
【図２】実施の形態の使用状態を示す斜視図である。FIG. 2 is a perspective view showing a usage state of the embodiment.
【図３】実施の形態の装置内発生磁界を示すグラフ図で
ある。FIG. 3 is a graph showing a magnetic field generated in the apparatus according to the embodiment.
【図４】従来の外乱磁界キャンセル装置を示す説明図で
ある。FIG. 4 is an explanatory diagram showing a conventional disturbance magnetic field canceling device.
【図５】従来の磁界の作用を示す説明図である。FIG. 5 is an explanatory diagram showing the action of a conventional magnetic field.
ｘ１，ｙ１，ｚ１ 磁界検出器 ｘ２，ｙ２，ｚ２ 増幅器 ｘ３，ｙ３，ｚ３ 減算回路 ｘ４，ｙ４，ｚ４ 電流出力回路 ｘ５，ｙ５，ｚ５ 分流器 ｘ６，ｙ６，ｚ６ 外乱磁界の打ち消し磁界用コイル ｘ７，ｙ７，ｚ７ 局部磁界打ち消しコイル ８ 外乱磁界発生源 ９ 判定装置 x1, y1, z1 magnetic field detector x2, y2, z2 amplifier x3, y3, z3 subtraction circuit x4, y4, z4 current output circuit x5, y5, z5 flow divider x6, y6, z6 Coil for canceling disturbance magnetic field x7, y7, z7 local magnetic field canceling coil 8 Disturbance magnetic field source 9 Judgment device
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭59−25726（ＪＰ，Ａ) 特開 平４−357481（ＪＰ，Ａ) 特開2000−37362（ＪＰ，Ａ) 特開 昭48−38972（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01R 33/02 - 33/10 H05K 9/00 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-59-25726 (JP, A) JP-A-4-357481 (JP, A) JP-A 2000-37362 (JP, A) JP-A-48-38972 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) G01R 33/02-33/10 H05K 9/00
Claims (4)
のコイルを備えた外乱磁界キャンセル装置において、 前記外乱磁界の打ち消し磁界用コイル近傍であって該コ
イルにおける磁束通過面の一部において前記磁束通過面
の法線方向と同一方向の磁界をキャンセルする局部磁界
打ち消しコイルと、 前記局部磁界打ち消しコイルの磁
束通過領域内に配置される前記外乱磁界を検知する磁界
検出器と、 前記磁界検出器の検知信号により前記外乱磁界の打ち消
し磁界用コイルと前記局部磁界打ち消しコイルに外乱磁
界キャンセル用電流を出力する電流出力回路と、を有す
ることを特徴とする外乱磁界キャンセル装置。1. A disturbance magnetic field canceling device comprising a coil for generating a magnetic field for canceling a disturbance magnetic field, comprising: a coil for canceling a disturbance magnetic field ;
The magnetic flux passing surface in the part of the magnetic flux passing surface in the yl
A local magnetic field canceling coil that cancels a magnetic field in the same direction as the normal direction of the magnetic field detector, a magnetic field detector that detects the disturbance magnetic field arranged in the magnetic flux passage region of the local magnetic field canceling coil, and a detection signal of the magnetic field detector. Thus, the disturbance magnetic field canceling device is characterized by including a coil for canceling the disturbance magnetic field and a current output circuit for outputting a disturbance magnetic field canceling current to the local magnetic field canceling coil.
界の打ち消し磁界用コイルが互いに直交する３軸の位置
ごとに対を成して対向配置されていることを特徴とする
請求項１記載の外乱磁界キャンセル装置。2. The disturbance according to claim 1, wherein the disturbance magnetic field canceling magnetic field coils having the local magnetic field canceling coils are arranged so as to face each other in pairs at positions of three axes orthogonal to each other. Magnetic field cancellation device.
ち消し磁界用コイルの面内に配置され、磁界検出器が局
部磁界打ち消しコイルの磁束中心位置に配置されている
ことを特徴とする請求項１または請求項２記載の外乱磁
界キャンセル装置。3. The local magnetic field canceling coil is arranged in a plane of the magnetic field canceling magnetic field coil, and the magnetic field detector is arranged at a magnetic flux center position of the local magnetic field canceling coil. The disturbance magnetic field canceling device according to claim 2.
磁界検出器と対を成して配置され外乱磁界を打ち消す磁
界を発生させるための打ち消し磁界用コイルと、前記磁
界検出器の位置に前記打ち消し磁界用コイルの発生磁界
の影響を一部分キャンセルして補正する磁界を発生する
局部磁界打ち消しコイルと、前記磁界検出器よりの出力
信号が供給される増幅器と、前記増幅器の信号から静磁
界成分を減算し変動磁界成分を出力する回路と、変動磁
界成分を励磁電流として出力する電流出力回路と、前記
電流出力を打ち消し磁界用コイルと局部磁界打ち消しコ
イルとに分流する分流器を備え、外乱磁界の打ち消し磁
界用コイルと局部磁界打ち消しコイルは前記電流出力回
路の出力に基づいて励磁されるように構成されているこ
とを特徴とする外乱磁界キャンセル装置。4. A magnetic field detector for detecting the disturbance field, and hit Chi erasing magnetic field coil for generating a magnetic field that cancels the are arranged in the magnetic field detector and a counter disturbance magnetic field, the magnetic field detector A local magnetic field canceling coil that generates a magnetic field that partially cancels and corrects the effect of the magnetic field generated by the canceling magnetic field coil at a position, an amplifier to which an output signal from the magnetic field detector is supplied, and a static signal from the amplifier signal. A circuit for subtracting a magnetic field component to output a fluctuating magnetic field component, a current output circuit for outputting a fluctuating magnetic field component as an exciting current, and a shunt for shunting the current output to a magnetic field canceling coil and a local magnetic field canceling coil, The disturbance magnetic field canceling magnetic field coil and the local magnetic field canceling coil are configured to be excited based on the output of the current output circuit. Magnetic field cancellation device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000089476A JP3406273B2 (en) | 2000-03-28 | 2000-03-28 | Disturbance magnetic field cancellation device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000089476A JP3406273B2 (en) | 2000-03-28 | 2000-03-28 | Disturbance magnetic field cancellation device |
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|---|---|
| JP2001281311A JP2001281311A (en) | 2001-10-10 |
| JP3406273B2 true JP3406273B2 (en) | 2003-05-12 |
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| JP2000089476A Expired - Fee Related JP3406273B2 (en) | 2000-03-28 | 2000-03-28 | Disturbance magnetic field cancellation device |
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| GB2411741B (en) * | 2004-03-03 | 2008-06-11 | Ims Nanofabrication Gmbh | Compensation of magnetic fields |
| JP5453192B2 (en) * | 2010-07-30 | 2014-03-26 | 鹿島建設株式会社 | Active magnetic shielding method and system for disturbance magnetic field |
| JP5541123B2 (en) * | 2010-11-30 | 2014-07-09 | 日立金属株式会社 | Disturbance magnetic field reduction apparatus and magnetic resonance imaging apparatus |
| JP6296843B2 (en) * | 2014-03-13 | 2018-03-20 | 株式会社東芝 | Paper sheet processing equipment |
| CN106353606A (en) * | 2016-11-18 | 2017-01-25 | 中国电子科技集团公司第四十研究所 | Device and method for omnidirectional detection of power-frequency electromagnetic field |
| JP6664568B1 (en) * | 2018-08-22 | 2020-03-13 | 旭化成エレクトロニクス株式会社 | Magnetic field measuring device, magnetic field measuring method, magnetic field measuring program |
| JP6936405B2 (en) | 2018-12-26 | 2021-09-15 | 旭化成エレクトロニクス株式会社 | Magnetic field measuring device |
| CN116631696A (en) * | 2022-02-11 | 2023-08-22 | 华为技术有限公司 | Magnetic shielding device and electron beam detection equipment |
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|---|---|---|---|---|
| NL7206464A (en) * | 1971-09-15 | 1973-03-19 | ||
| JPS5925726A (en) * | 1982-07-31 | 1984-02-09 | 株式会社島津製作所 | Diagnostic observation apparatus |
| JPH0810250B2 (en) * | 1991-05-13 | 1996-01-31 | 大同ほくさん株式会社 | Magnetic noise eliminator using SQUID |
| JP2000037362A (en) * | 1998-07-21 | 2000-02-08 | Toshiba Corp | Device for removing environment noise magnetic field |
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