JPH0472705A - Electromagnet device - Google Patents
Electromagnet deviceInfo
- Publication number
- JPH0472705A JPH0472705A JP18585590A JP18585590A JPH0472705A JP H0472705 A JPH0472705 A JP H0472705A JP 18585590 A JP18585590 A JP 18585590A JP 18585590 A JP18585590 A JP 18585590A JP H0472705 A JPH0472705 A JP H0472705A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- magnetic flux
- thickness
- radius
- end plate
- 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.)
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Links
- 230000004907 flux Effects 0.000 claims abstract description 52
- 230000007423 decrease Effects 0.000 abstract description 6
- 229920006395 saturated elastomer Polymers 0.000 abstract description 4
- 230000008859 change Effects 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 5
- 239000000696 magnetic material Substances 0.000 description 3
- 238000002595 magnetic resonance imaging Methods 0.000 description 3
- 238000003384 imaging method Methods 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 1
- 230000009191 jumping Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
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Abstract
Description
この発明は、例えば磁気共鳴イメージングシステムの撮
像空間としての磁界発生空間を形成するのに利用する電
磁石装置に関するものである。The present invention relates to an electromagnet device used, for example, to form a magnetic field generation space as an imaging space of a magnetic resonance imaging system.
第８図は従来の電磁石装置を示す斜視図であり、図にお
いて、１は略円筒形（ここでは八角形）の磁性体、２は
この磁性体１の両端に取付けられた中空円板状（ここで
は外周が八角形）の磁性体鏡板、３は磁性体１および磁
性体鏡板２が作る空間に設置された磁界発生用コイルを
内蔵する電磁石３である。５は電磁石３の所望磁界発生
空間であり、これが磁気共鳴イメージングシステムにお
いて撮像空間に相当する。
第９図は第８図のＡ−Ａ線断面図であり、ここには電磁
石３が磁性体１とほぼ同軸の、円筒形の磁界発生用コイ
ル４を内蔵した状態で示されている。
次に動作について説明する。
円筒形の磁界発生用コイル４で発生した磁界は、磁性体
１及び磁性体鏡板２で構成された磁気シールドが無い場
合、所望磁界発生空間５以外の電磁石装置の外部に大き
な漏洩磁界空間を発生することとなる。一方電磁石３が
設置される周辺には、磁界の存在により正常な機能が損
われる機器、例えばカラーテレビ、磁気記録装置等が置
かれることがある。そこで、これらの機器に対し、電磁
石３の漏洩磁界が影響を及ぼさないように、磁性体１と
磁性体鏡板２が磁界発生用コイル４を包囲するようにし
、これによって漏洩磁界空間を縮減する対策がとられて
いる。すなわち、このような磁気しゃへい効果は、第１
０図に示すように、磁界発生用コイル４で発生した磁束
６の大部分が透磁率の高い磁性体鏡板２の内円周付近に
飛び込み、磁性体鏡板２内を半径方向に放射状に進み、
さらに、磁性体鏡板２から磁性体１を通り、反対側の磁
性体鏡板２を通過して、磁界発生用コイル４内にもどる
閉ループを形成することにより達成される。磁界発生用
コイル４で発生した磁束６が磁性体鏡板２に飛び込む量
７の分布は、第１１図に示す通りであり、磁性体鏡板２
の内円周部で最大となり、外円周部に向うに従って指数
関数的に減少する特性を示す。次に、第１１図に示すよ
うに、磁性体鏡板２の内周端部より外周方向に座標ｒを
採り、例えばｒ＝ｒ、での磁性体鏡板２内部を流れる磁
束量を求めると、磁束量はｒ＝ｏからｒ＝ｒｌまでに磁
性体鏡板２に飛び込む磁束７の積分値で示され、第１３
図に示すような特性となる。
一方、磁性体鏡板２内部の任意の面、例えば第１２図の
断面８の磁束密度については、磁性体鏡板２内のその面
での通過磁束量を磁束の流れる方向に垂直な磁性体鏡板
２の断面８０面積で割ることにより求めることができる
。この断面積ＳはＳ＝２π（ｒ＋Ｒｈ ） ・ｔ
（１）となり、座標ｒと断面積Ｓの関係を示すと、第
１４図のようになる。但し、Ｒ２は磁性体鏡板２の中空
内円半径、ｔは磁性体鏡板２の厚さである。この結果、
第１３図の磁束特性と第１４図の断面積の変化とから分
かるように磁性体腕ｖｉ２内部の磁束密度の変化は、第
１５図に示すようになる。この第１５図は磁性体鏡板２
内の等磁束密度域が同心杖に分布し、磁束密度の最大値
は、その鏡板２の比較的内側に存在していることを示し
ている。
また、磁気シールドの厚さｔは、最も磁束密度が高くな
る部分で磁性体鏡板２に使用する磁性体の飽和磁束密度
を越えない条件から決定されている。FIG. 8 is a perspective view showing a conventional electromagnet device. In the figure, 1 is a substantially cylindrical (here, octagonal) magnetic body, and 2 is a hollow disc-shaped body (2) attached to both ends of this magnetic body 1. Here, the magnetic end plate 3 having an octagonal outer periphery is an electromagnet 3 having a built-in magnetic field generating coil installed in a space created by the magnetic body 1 and the magnetic end plate 2. 5 is a desired magnetic field generation space of the electromagnet 3, which corresponds to the imaging space in the magnetic resonance imaging system. FIG. 9 is a cross-sectional view taken along the line A--A in FIG. 8, in which the electromagnet 3 is shown with a built-in cylindrical magnetic field generating coil 4 that is substantially coaxial with the magnetic body 1. Next, the operation will be explained. The magnetic field generated by the cylindrical magnetic field generating coil 4 generates a large leakage magnetic field space outside the electromagnetic device other than the desired magnetic field generating space 5 when there is no magnetic shield composed of the magnetic body 1 and the magnetic end plate 2. I will do it. On the other hand, in the vicinity where the electromagnet 3 is installed, devices whose normal functions are impaired by the presence of a magnetic field, such as a color television, a magnetic recording device, etc., may be placed. Therefore, in order to prevent the leakage magnetic field of the electromagnet 3 from affecting these devices, the magnetic body 1 and the magnetic mirror plate 2 surround the magnetic field generation coil 4, thereby reducing the leakage magnetic field space. is taken. In other words, this magnetic shielding effect is caused by the first
As shown in Figure 0, most of the magnetic flux 6 generated by the magnetic field generating coil 4 jumps into the vicinity of the inner circumference of the magnetic end plate 2 with high magnetic permeability, travels radially inside the magnetic end plate 2, and
Furthermore, this is achieved by forming a closed loop from the magnetic end plate 2, through the magnetic body 1, through the magnetic end plate 2 on the opposite side, and back into the magnetic field generating coil 4. The distribution of the amount 7 of the magnetic flux 6 generated by the magnetic field generating coil 4 jumping into the magnetic end plate 2 is as shown in FIG.
It exhibits a characteristic that it is maximum at the inner circumference and decreases exponentially toward the outer circumference. Next, as shown in FIG. 11, taking the coordinate r from the inner circumferential end of the magnetic end plate 2 in the outer circumferential direction and finding the amount of magnetic flux flowing inside the magnetic end plate 2 at, for example, r=r, the magnetic flux is The amount is indicated by the integral value of the magnetic flux 7 that jumps into the magnetic mirror plate 2 from r=o to r=rl, and the 13th
The characteristics are as shown in the figure. On the other hand, regarding the magnetic flux density at an arbitrary surface inside the magnetic body end plate 2, for example, the cross section 8 in FIG. It can be determined by dividing by the cross-sectional area of 80. This cross-sectional area S is S=2π(r+Rh) ・t
(1), and the relationship between the coordinate r and the cross-sectional area S is as shown in FIG. However, R2 is the radius of the hollow inner circle of the magnetic end plate 2, and t is the thickness of the magnetic end plate 2. As a result,
As can be seen from the magnetic flux characteristics in FIG. 13 and the change in cross-sectional area in FIG. 14, the change in magnetic flux density inside the magnetic arm vi2 is as shown in FIG. 15. This figure 15 shows the magnetic end plate 2.
The area of equal magnetic flux density within is distributed in a concentric manner, and the maximum value of magnetic flux density is located relatively inside the mirror plate 2. Further, the thickness t of the magnetic shield is determined based on the condition that the portion where the magnetic flux density is highest does not exceed the saturation magnetic flux density of the magnetic material used for the magnetic end plate 2.
従来の電磁石装置は以上のように構成されているので、
外部漏洩磁界を低減するための磁性体鏡板２の厚さはそ
の一部の磁束密度の高い領域により決定され、この磁性
体鏡板２の内周端付近や外周端付近では必要以上の厚さ
となり、これが装置全体の重量を不必要に大きくしてし
まうなどの課題があった。
この発明は上記のような課題を解消するためになされた
もので、磁性体鏡板を磁束が通過する際に、磁性体鏡板
の全領域で磁気飽和することの無い合理的な厚さとする
ことにより、装置全体の重量を低減することができる電
磁石装置を得ることを目的とする。Since the conventional electromagnet device is configured as described above,
The thickness of the magnetic end plate 2 for reducing the external leakage magnetic field is determined by some regions with high magnetic flux density, and the thickness near the inner and outer edges of the magnetic end plate 2 is more than necessary. , which caused problems such as unnecessarily increasing the weight of the entire device. This invention was made in order to solve the above-mentioned problems, and by making the magnetic head plate have a reasonable thickness that will not cause magnetic saturation in the entire area when the magnetic flux passes through the magnetic head plate. The object of the present invention is to obtain an electromagnetic device that can reduce the weight of the entire device.
この発明に係る電磁石装置は、磁性体鏡板に対して、こ
の磁性体鏡板内を通過する磁束量と磁束通過断面積との
比率で決まる磁束密度が鏡板の径方向の各領域でその磁
性体鏡板の飽和磁束密度以下となるように、上記各領域
で厚い部分と薄い部分を設けたものである。In the electromagnet device according to the present invention, the magnetic flux density determined by the ratio of the amount of magnetic flux passing through the magnetic end plate to the cross-sectional area of the magnetic flux passing through the magnetic end plate is determined in each region in the radial direction of the magnetic end plate. A thick portion and a thin portion are provided in each of the above regions so that the saturation magnetic flux density is less than or equal to the saturation magnetic flux density.
この発明における！磁石装置は、磁性体ｗｉＬ板が漏洩
磁界低減のために通過させる磁束量に対して径方向の各
領域で必要かつ十分な厚さとされるので、磁性体鏡板の
軽量化、さらには装置全体の軽量化を実現可能にする。In this invention! The magnet device has a necessary and sufficient thickness in each region in the radial direction for the amount of magnetic flux that the magnetic wiL plate passes through in order to reduce leakage magnetic fields, so it is possible to reduce the weight of the magnetic end plate and further reduce the weight of the entire device. Make weight reduction possible.
以下、この発明の一実施例を図について説明する。第１
図において１は略円筒状の磁性体、９は径方向で厚さの
異なる中孔を有する円板状の磁性体鏡板、３は磁性体１
とほぼ同軸の円筒形の磁界発生用コイル４を内蔵した電
磁石、５は所望磁界発生空間である。
第２図は上記磁性体鏡板９の詳細を示す。この磁性体鏡
板９は磁界発生用コイル４と略同軸、同心円状に形成さ
れ、かつ径方向に２種類の厚さの部分１０，１１．１２
から構成され、このうち厚さの厚い部分１０の内半径は
磁性体鏡＠、９の内周半径より大きく、厚さの厚い部分
１０の外半径は磁性体鏡板９の外周半径より小さい。そ
して、１１゜１２は磁性体鏡板９の厚さの薄い部分とな
っている。そして、厚い部分１０は磁性体鏡板９を通る
磁束量の多い部分に対応させである。
次に動作について説明する。
磁界発生用コイル４に磁束が発生すると、その磁束の大
部分が透磁率の高い磁性体鏡板９の内円周付近に飛び込
み、さらに、磁性体鏡板９から磁性体１を通り、反対側
の磁性体鏡板９を通過して磁界発生用コイル４にもどる
。このような磁束の閉ループの流れにより、電磁石装置
の外部漏洩磁界を低減する。この基本的動作については
、従来装置と同一である。この場合において、磁性体鏡
板９への磁束の飛び込み状態も従来例と同様であり、磁
性体鏡板９の内円周部で最大であり、外円周部に向うに
従って指数関数的に減少する。このため、磁性体鏡板９
内の通過磁束量と鏡板内周端から外周方向への距離の関
係は、従来例同様に第１３図のようになる。
一方、磁性体鏡板９は第１図及び第２図に示すように半
径方向に厚さの異なる部分を有し、磁性体鏡板９内を通
過する磁束に垂直な断面積と磁性体鏡板９の内周端から
外周方向への距離の関係は第３図の実線のようになる。
この断面積特性は（１）式において磁性体鏡板９の厚さ
ｔが部分的に異なる値を持つとすれば容易に求まる。な
お、この第３図には、従来例として示した磁性体鏡板２
の厚さが−様な場合の断面積特性を破線で示しである。
この実施例では、磁性体鏡板９の内周側と外周側で従来
例より断面積を減少させてあり、これを実線で示しであ
る。このため、このような形状の磁性体鏡板９内の磁束
密度は、磁性体鏡板９の内周端からの距離との関係で示
すと第４図に示すようになり、これが第２図で示した磁
束量を第３図で示した断面積で割ったものとなる。
この第４図では、従来例で示した磁性体鏡板２の厚さが
−様な場合の磁束密度の特性を破線で示してあり、この
発明の実施例では、この破線の値に対し、断面積の減少
部分で磁束密度が上昇していることを実線で示しである
。この場合において、上記のような磁束密度の上昇部分
でも磁性体鏡板９に使用されている磁性体の飽和磁束密
度以下となるように、磁性体鏡板９の厚さを選定するこ
とにより、磁気シールドの効果を確保している。
すなわち、この発明では、磁性体鏡板９のうち厚い部分
の厚さは、これを−様な厚さで構成する場合に必要かつ
十分な厚さと同一とし、一方、厚さの薄い部分について
は、磁界発生用コイルの寸法や出力磁界の強度により異
なり、厚い部分以下のその電磁石固有の適当な厚さが選
定される。この選定された薄い部分１１．１２の厚さに
対して、内円周側の厚さの薄い部分１１が飽和磁束密度
に達することのない半径で、厚さの厚い部分１０の内半
径が決定される。また、厚い部分１０の外半径は（１）
式で示したように、厚さ一定の条件では半径の増大に伴
い断面積が増加するため、厚さを薄くしても厚さ減によ
る断面積の減少が半径増大による断面積増と相殺し、磁
性体鏡板９内の磁束が飽和しない半径とするよう決定さ
れる。
なお、上記、実施例では厚さの厚い部分１０を電磁石３
方向に形成したものを示したが、第５図に示すように、
磁性体鏡板９の外側の対応位置に形成したり、第６図に
示すように、磁性体鏡板９の内外側の対応位置に形成し
たり、第７図に示すように、磁性体鏡板９の内側に、磁
束密度を等化するような異った３種類以上の厚さとする
こともでき、上記実施例と同様の効果を奏する。An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 is a substantially cylindrical magnetic body, 9 is a disk-shaped magnetic head plate having a hole with a different thickness in the radial direction, and 3 is a magnetic body 1
5 is a desired magnetic field generation space. FIG. 2 shows details of the magnetic end plate 9. As shown in FIG. This magnetic end plate 9 is formed approximately coaxially and concentrically with the magnetic field generating coil 4, and has two different thicknesses 10, 11 and 12 in the radial direction.
The inner radius of the thicker portion 10 is larger than the inner radius of the magnetic mirror plate 9, and the outer radius of the thicker portion 10 is smaller than the outer radius of the magnetic mirror plate 9. 11° and 12 are thinner portions of the magnetic end plate 9. The thick portion 10 corresponds to a portion where a large amount of magnetic flux passes through the magnetic mirror plate 9. Next, the operation will be explained. When magnetic flux is generated in the magnetic field generating coil 4, most of the magnetic flux jumps into the vicinity of the inner circumference of the magnetic mirror plate 9 with high magnetic permeability, and then passes from the magnetic mirror plate 9 through the magnetic body 1 to the magnetic flux on the opposite side. It passes through the body mirror plate 9 and returns to the magnetic field generating coil 4. This closed loop flow of magnetic flux reduces the external leakage magnetic field of the electromagnetic device. This basic operation is the same as the conventional device. In this case, the state of the magnetic flux flowing into the magnetic mirror plate 9 is the same as in the conventional example, and is maximum at the inner circumferential portion of the magnetic mirror plate 9 and decreases exponentially toward the outer circumferential portion. For this reason, the magnetic end plate 9
The relationship between the amount of magnetic flux passing through the inside and the distance from the inner circumferential end of the mirror plate toward the outer circumferential direction is as shown in FIG. 13, as in the conventional example. On the other hand, as shown in FIGS. 1 and 2, the magnetic head plate 9 has portions with different thicknesses in the radial direction, and the cross-sectional area perpendicular to the magnetic flux passing through the magnetic head plate 9 and the cross-sectional area of the magnetic head plate 9 The relationship between the distance from the inner circumferential end to the outer circumferential direction is as shown by the solid line in FIG. This cross-sectional area characteristic can be easily determined by assuming that the thickness t of the magnetic end plate 9 has partially different values in equation (1). Note that FIG. 3 shows the magnetic end plate 2 shown as a conventional example.
The broken line shows the cross-sectional area characteristics when the thickness of the film is -like. In this embodiment, the cross-sectional area on the inner and outer circumferential sides of the magnetic end plate 9 is reduced compared to the conventional example, and this is shown by a solid line. Therefore, the magnetic flux density in the magnetic head plate 9 having such a shape is shown in FIG. 4 in relation to the distance from the inner peripheral end of the magnetic head plate 9, which is shown in FIG. It is calculated by dividing the magnetic flux amount by the cross-sectional area shown in FIG. In this FIG. 4, the characteristic of the magnetic flux density when the thickness of the magnetic end plate 2 shown in the conventional example is - is shown by a broken line. The solid line indicates that the magnetic flux density increases in the area where the area decreases. In this case, the thickness of the magnetic end plate 9 is selected so that even in the portion where the magnetic flux density increases as described above, the magnetic flux density is below the saturation magnetic flux density of the magnetic material used in the magnetic end plate 9. The effectiveness of the system is ensured. That is, in this invention, the thickness of the thick portion of the magnetic mirror plate 9 is the same as the necessary and sufficient thickness when configuring it with a thickness like -, while the thin portion is The thickness varies depending on the dimensions of the magnetic field generating coil and the intensity of the output magnetic field, and an appropriate thickness unique to the electromagnet is selected, which is less than the thick part. With respect to the thickness of the selected thin portions 11 and 12, the inner radius of the thick portion 10 is determined at a radius at which the thin portion 11 on the inner circumferential side does not reach the saturation magnetic flux density. be done. Also, the outer radius of the thick portion 10 is (1)
As shown in the formula, when the thickness is constant, the cross-sectional area increases as the radius increases, so even if the thickness is made thinner, the decrease in cross-sectional area due to the decrease in thickness offsets the increase in cross-sectional area due to the increase in radius. , is determined to be a radius at which the magnetic flux within the magnetic end plate 9 is not saturated. In addition, in the above embodiment, the thick portion 10 is connected to the electromagnet 3.
Although the one formed in the direction is shown, as shown in Fig. 5,
They may be formed at corresponding positions on the outside of the magnetic end plate 9, or they may be formed at corresponding positions on the inside and outside of the magnetic end plate 9 as shown in FIG. The inner side can have three or more different thicknesses so as to equalize the magnetic flux density, and the same effect as in the above embodiment can be achieved.
以上のように、この発明によれば磁性体鏡板内を通過す
る磁束密度が、該磁性体鏡板の径方向の各領域で飽和磁
束密度以下となるように、該磁性体鏡板に対して上記各
領域で厚い部分と薄い部分を設けるように構成したので
、上記磁性体鏡板を必要なシールド効果を維持しながら
軽量子およびローコスト化でき、これにより磁気共鳴イ
メージングシステムの軽量化を図れるものが得られる効
果がある。As described above, according to the present invention, each of the above-mentioned points is applied to the magnetic end plate so that the magnetic flux density passing through the magnetic end plate is equal to or lower than the saturation magnetic flux density in each region in the radial direction of the magnetic end plate. Since it is configured to have a thick portion and a thin portion in each region, the magnetic mirror plate can be made lightweight and low cost while maintaining the necessary shielding effect, thereby making it possible to reduce the weight of the magnetic resonance imaging system. effective.
第１図はこの発明の一実施例による電磁石装置を示す一
部の断面図、第２図は第１図における磁性体鏡板を示す
斜視図、第３図は第１図の磁性体鏡板各部の断面積を示
す特性図、第４図は第１図の磁性体鏡板各部の磁束密度
を示す特性図、第５図、第６図および第７図は電磁石装
置の他の実施例を示す一部の断面図、第８図は従来の電
磁石装置を示す斜視図、第９図は第８図における電磁石
装置の内部構造を示すＡ−Ａ線断面図、第１０図は電磁
石装置のシールド効果を示す説明図、第１１図は電磁石
装置における磁束分布を示す説明図、第１２図は！磁石
装置における所定断面内の磁束密度分布を説明する説明
図、第１３図は磁性体鏡板内の磁束量を示す特性図、第
１４図は従来の磁性体鏡板各部の断面積を示す特性図、
第１５図は従来の磁性体鏡板各部の磁束密度を示す特性
図である。
１は磁性体、３は電磁石、４は磁界発生用コイル、９は
磁性体鏡板、１０は厚い部分、１１．１２は薄い部分。
なお、図中、同一符号は同一、又は相当部分を示す。FIG. 1 is a cross-sectional view of a part of an electromagnet device according to an embodiment of the present invention, FIG. 2 is a perspective view of the magnetic end plate in FIG. 1, and FIG. 3 is a partial sectional view of the magnetic end plate in FIG. A characteristic diagram showing the cross-sectional area, FIG. 4 is a characteristic diagram showing the magnetic flux density of each part of the magnetic end plate in FIG. 1, and FIGS. 5, 6, and 7 are parts showing other embodiments of the electromagnet device. 8 is a perspective view showing a conventional electromagnet device, FIG. 9 is a sectional view taken along line A-A showing the internal structure of the electromagnet device in FIG. 8, and FIG. 10 shows the shielding effect of the electromagnet device. An explanatory diagram, Fig. 11 is an explanatory diagram showing the magnetic flux distribution in an electromagnet device, and Fig. 12 is! An explanatory diagram illustrating the magnetic flux density distribution within a predetermined cross section in a magnet device, FIG. 13 is a characteristic diagram showing the amount of magnetic flux in the magnetic end plate, and FIG. 14 is a characteristic diagram showing the cross-sectional area of each part of the conventional magnetic end plate.
FIG. 15 is a characteristic diagram showing the magnetic flux density of each part of a conventional magnetic end plate. 1 is a magnetic material, 3 is an electromagnet, 4 is a coil for generating a magnetic field, 9 is a magnetic mirror plate, 10 is a thick portion, and 11.12 is a thin portion. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.
Claims (1)
に磁気シールドを形成する磁性体鏡板と、該磁性体鏡板
と上記磁性体との間に形成された空間に設置されて、磁
界発生用コイルを内蔵する電磁石とを備えた電磁石装置
において、上記磁性体鏡板内を通過する磁束密度が、該
磁性体鏡板の径方向の各領域で飽和磁束密度以下となる
ように、該磁性体鏡板の上記各領域に厚い部分と薄い部
分を設けたことを特徴とする電磁石装置。A magnetic head plate attached to both ends of a cylindrical magnetic body to form a magnetic shield together with the magnetic body, and a magnetic field generating coil installed in a space formed between the magnetic head plate and the magnetic body. In an electromagnetic device equipped with an electromagnet having a built-in electromagnet, the magnetic flux density of the magnetic body end plate is adjusted so that the magnetic flux density passing through the magnetic body end plate is equal to or less than the saturation magnetic flux density in each region in the radial direction of the magnetic body end plate. An electromagnetic device characterized by having a thick portion and a thin portion in each region.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18585590A JPH0472705A (en) | 1990-07-13 | 1990-07-13 | Electromagnet device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18585590A JPH0472705A (en) | 1990-07-13 | 1990-07-13 | Electromagnet device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0472705A true JPH0472705A (en) | 1992-03-06 |
Family
ID=16178059
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18585590A Pending JPH0472705A (en) | 1990-07-13 | 1990-07-13 | Electromagnet device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0472705A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003090863A1 (en) * | 2002-04-24 | 2003-11-06 | Mcubetechnology Co., Ltd. | A stimulation coil using magnetic mirror and use thereof |
-
1990
- 1990-07-13 JP JP18585590A patent/JPH0472705A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2003090863A1 (en) * | 2002-04-24 | 2003-11-06 | Mcubetechnology Co., Ltd. | A stimulation coil using magnetic mirror and use thereof |
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