JP2715530B2 - Electromagnetic shielding material - Google Patents
Electromagnetic shielding materialInfo
- Publication number
- JP2715530B2 JP2715530B2 JP1072123A JP7212389A JP2715530B2 JP 2715530 B2 JP2715530 B2 JP 2715530B2 JP 1072123 A JP1072123 A JP 1072123A JP 7212389 A JP7212389 A JP 7212389A JP 2715530 B2 JP2715530 B2 JP 2715530B2
- Authority
- JP
- Japan
- Prior art keywords
- housing
- gap
- magnetic
- plate
- housing 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.)
- Expired - Lifetime
Links
Landscapes
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は電子機器より発生する不要な電磁波の抑制を
行う電磁遮へい材に関し、特に電子機器筐体の間隙部か
ら漏洩する電磁波を遮へいする遮へい材に関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic shielding material for suppressing unnecessary electromagnetic waves generated from an electronic device, and more particularly, to a shielding material for shielding electromagnetic waves leaking from a gap in an electronic device housing. About materials.
従来、金属板で構成された電子機器筐体の間隙部から
の電磁波の漏洩を防ぐためには間隙部をできる限り小さ
くするか、又は、間隙部に透磁率が大きい磁性体を挿入
するなどの処置が取られていた（例えば電子情報通信学
会研究会資料、清水他,EMCJ83−41,P.39）。Conventionally, in order to prevent leakage of electromagnetic waves from the gap of an electronic device housing formed of a metal plate, measures such as making the gap as small as possible or inserting a magnetic material having a high magnetic permeability into the gap are used. (For example, IEICE Technical Report, Shimizu et al., EMCJ83-41, p.39).
上述の技術は損失の大きい磁性体中の伝搬損失、境界
面でのインピーダンスの不連続による反射損失により、
電磁波の漏洩を軽減するものである。但し、この２つの
損失は両者とも対象とする電磁波の波長λと磁性体の幅
Ｗとの関係によって変化し、Ｗ≪λでは著しく損失が小
さくなるので低周波では効果が低下するという欠点があ
る。The above-mentioned technology is due to the propagation loss in a magnetic material with large loss, the reflection loss due to the discontinuity of impedance at the interface,
This is to reduce leakage of electromagnetic waves. However, these two losses change depending on the relationship between the wavelength λ of the target electromagnetic wave and the width W of the magnetic material, and the loss is extremely small when W 著 し く λ, so that the effect is reduced at low frequencies. .
本発明の目的は上記課題を解決した電磁遮へい材を提
供することにある。An object of the present invention is to provide an electromagnetic shielding material that solves the above-mentioned problems.
上記目的を達成するため、本発明による電磁遮へい材
においては、金属製筐体を旋蓋する金属製筐体板上に、
透磁率が筐体外側から内側に向けて大きくなる方向の勾
配を有する磁性体を設けたものである。In order to achieve the above object, in the electromagnetic shielding material according to the present invention, on a metal housing plate for turning the metal housing,
A magnetic body having a gradient in a direction in which the magnetic permeability increases from the outside to the inside of the housing is provided.
次に、本発明について図面を参照して説明する。第１
図は金属板で構成される筐体のモデルを示している。Ｂ
は金属製筐体、Ａはその開口を旋蓋する金属製筐体板で
ある。筐体Ｂの開口縁を筐体板Ａで旋蓋し、ネジ止めで
一体化する。このとき、筐体板Ａと筐体Ｂ間の重合部Ｃ
の間隙を通して筐体内部に発生した電磁波が外部に漏洩
する。本発明は間隙を形成する重合部Ｃに対応して筐体
板Ａ上に磁性体を設けるものである。第２図（ａ）に示
したように筐体板Ａの上面には重合部Ｃに対応して磁性
体Ｄを盛り付ける。この重合部Ｃに設けた磁性体Ｄの透
磁率は第２図（ｂ）のように筐体外側から内側へ向かっ
て大きくなる方向で勾配を持つ。Next, the present invention will be described with reference to the drawings. First
The figure shows a model of a housing made of a metal plate. B
Denotes a metal housing, and A denotes a metal housing plate for turning the opening. The opening edge of the housing B is swirled with the housing plate A and integrated with screws. At this time, the overlapping portion C between the housing plate A and the housing B
The electromagnetic wave generated inside the housing leaks to the outside through the gap. In the present invention, a magnetic body is provided on the housing plate A corresponding to the overlapping portion C forming the gap. As shown in FIG. 2A, a magnetic body D is provided on the upper surface of the housing plate A in correspondence with the overlapping portion C. The magnetic permeability of the magnetic body D provided in the overlapping portion C has a gradient in a direction of increasing from the outside to the inside of the housing as shown in FIG. 2B.
磁性体の透磁率の勾配は、いかなる方法を用いて実現
してもよい。第３図〜第６図にその例を示した。第３図
は筐体板Ａの上に断面が三角形の形状の磁性体Ｄを設け
るもので、重合部Ｃの間隙に対応して磁性体Ｄの占める
割合を筐体内側で大きくなるようにし、等価的に間隙部
の透磁率の勾配を得るものである。Ｅは筐体板Ａの面が
平坦になるように設けた樹脂の層である。第４図は筐体
板Ａの周縁に断面が三角形となるように端縁側が上傾す
る溝を設け、これに同じ形状の断面の磁性体Ｄを埋め込
んだものであり、等価的な透磁率は第３図の場合と同じ
く勾配を持つ。第５図は重合部Ｃに対応して筐体板Ａ上
に相互の間隔を端縁側に広げて細長い形状の磁性体D,D,
…を並べたものである。磁性体の配列による密度の変化
によって透磁率の勾配が等価的に得られる。The gradient of the magnetic permeability of the magnetic material may be realized by any method. 3 to 6 show examples. FIG. 3 shows a case in which a magnetic body D having a triangular cross section is provided on the housing plate A, and the proportion of the magnetic body D occupying the inside of the housing is increased in accordance with the gap between the overlapping portions C, The gradient of the magnetic permeability of the gap is equivalently obtained. E is a resin layer provided so that the surface of the housing plate A becomes flat. FIG. 4 shows a case in which a groove whose upper end is inclined so as to form a triangular cross section is provided in the peripheral edge of the housing plate A, and a magnetic body D having a cross section of the same shape is embedded in the groove. Has the same gradient as in FIG. FIG. 5 is a diagram showing an elongated magnetic material D, D,
... are arranged. A gradient in magnetic permeability can be equivalently obtained by a change in density due to the arrangement of the magnetic materials.
第３図〜第５図は筐体板Ａ端部の間隙となる部分にの
み磁性体を設けたが、当然のこと乍ら第６図に示すよう
に筐体板Ａの全面に渡って透磁率が勾配を有する磁性体
Ｄを設けてもよい。第３図〜第６図のどれを採用するか
は筐体、間隙の形状によって決める。In FIGS. 3 to 5, the magnetic material is provided only in a portion which becomes a gap between the ends of the casing plate A. However, as shown in FIG. A magnetic body D having a gradient in magnetic susceptibility may be provided. Which one of FIGS. 3 to 6 is adopted depends on the shape of the housing and the gap.
透磁率の勾配が間隙からの漏洩防止に与える影響につ
いては厳密にはMaxwell方程式において、透磁率μが位
置の画数である状態での伝搬の式を導かなくてはならな
いが、定性的には伝搬速度ｖが に反比例することで説明できる。第７図において、ｘ方
向に透磁率が大きくなる媒質中をｙ方向に進む電磁波を
考える。Strictly speaking, the influence of the gradient of permeability on the prevention of leakage from the gap must be derived from the equation of propagation in the state where permeability μ is the number of strokes in the Maxwell equation, but qualitatively Speed v Can be explained by being inversely proportional to In FIG. 7, consider an electromagnetic wave traveling in the y direction in a medium whose magnetic permeability increases in the x direction.
であるから伝搬速度は、ｘが大きいところほど小さくな
る。従って、t1,t2…t5と時間が経つにつれて波面が第
７図中、右の方へ傾き、伝搬方向Ｐはｙ軸からｘ軸の方
へ曲がる。すなわち、電磁波はμの大きい方向へ向かっ
て進むようになり、μの小さい方向とは反対の方向へ向
かう。従って、以上述べたように重合部の間隙が筐体内
側へ向かってμが大きくなるように勾配を持った磁性体
を用いれば電磁波は間隙から外へ漏洩する成分が抑制さ
れる。 Therefore, the propagation velocity decreases as x increases. Accordingly, as time elapses from t 1 , t 2 to t 5 , the wavefront tilts rightward in FIG. 7 and the propagation direction P bends from the y-axis toward the x-axis. That is, the electromagnetic wave travels in the direction in which μ is large, and in the direction opposite to the direction in which μ is small. Therefore, as described above, if a magnetic material having a gradient such that the gap of the overlapping portion becomes larger toward the inside of the housing is used, the component of the electromagnetic wave leaking out of the gap is suppressed.
以上説明したように、本発明によれば金属筐体と、こ
れを旋蓋する筐体板との間に形成される重合部の間隙部
内側に向かって透磁率が大きくなるように磁性体を設け
ることにより筐体の間隙部からの電磁波の漏洩を抑制で
きる効果がある。As described above, according to the present invention, the magnetic body is formed such that the magnetic permeability increases toward the inside of the gap portion of the overlapped portion formed between the metal housing and the housing plate that turns the metal housing. Providing the cover has the effect of suppressing leakage of electromagnetic waves from the gap of the housing.
第１図は本発明で対称とする金属板よりなる電子機器筐
体の斜視図、第２図（ａ）は筐体板の構造を示す平面
図、（ｂ）は（ａ）の（イ）−（イ）線における磁性体
部の透磁率の分布を示す図、第３図，第４図，第５図及
び第６図は等価的に透磁率の勾配を得るための磁性体の
形状の実施例を示す図、第７図は本発明の原理を示す図
である。 Ａ……金属の筐体板、Ｂ……金属の筐体 Ｃ……重合部、Ｄ……磁性体 Ｅ……樹脂の層FIG. 1 is a perspective view of an electronic device housing made of a metal plate symmetrical in the present invention, FIG. 2 (a) is a plan view showing the structure of the housing plate, and FIG. 1 (b) is (a) of FIG. FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG. 6 show the distribution of the magnetic permeability of the magnetic body portion along the line (a), and FIG. FIG. 7 is a view showing an embodiment, and FIG. 7 is a view showing the principle of the present invention. A: metal housing plate, B: metal housing C: overlapping portion, D: magnetic material E: resin layer
Claims (1)
透磁率が筺体板と前記筺体とが接合される間隙部は小さ
く筺体板の内側に向かって大きくなる方向の勾配を有
し、前記間隙部から漏洩する電磁波の伝搬方向を前記筺
体板の内側方向に進行方向を曲げる磁性体を設けた ことを特徴とする電磁遮へい材。1. A metal housing plate for turning a metal housing,
The gap in which the magnetic permeability is joined to the housing plate and the housing has a gradient in a direction in which the gap is small and increases toward the inside of the housing plate, and the propagation direction of the electromagnetic wave leaking from the gap is set to the inside direction of the housing plate. An electromagnetic shielding material characterized in that a magnetic body that bends the direction of travel is provided on the surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1072123A JP2715530B2 (en) | 1989-03-23 | 1989-03-23 | Electromagnetic shielding material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1072123A JP2715530B2 (en) | 1989-03-23 | 1989-03-23 | Electromagnetic shielding material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02250397A JPH02250397A (en) | 1990-10-08 |
| JP2715530B2 true JP2715530B2 (en) | 1998-02-18 |
Family
ID=13480246
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1072123A Expired - Lifetime JP2715530B2 (en) | 1989-03-23 | 1989-03-23 | Electromagnetic shielding material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2715530B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3098313B2 (en) * | 1991-12-18 | 2000-10-16 | 日本電気株式会社 | Electromagnetic shielding case |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55150601U (en) * | 1979-04-13 | 1980-10-30 |
-
1989
- 1989-03-23 JP JP1072123A patent/JP2715530B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02250397A (en) | 1990-10-08 |
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