JPH04268799A - Electromagnetic shielding chamber - Google Patents

Abstract

PURPOSE:To enable an electromagnetic shielding chamber to be enhanced in shielding capacity by a method wherein a high frequency current is prevented from leaking from an electromagnetic shielding panel mounting bracket, an electromagnetic shielding panel, and a contact part between the door and the wall of an electromagnetic shielding chamber. CONSTITUTION:An electromagnetic shielding chamber is composed of electromagnetic shielding panels 2 formed of a core material 4 and a metal plate 3 and plate-like coupling pieces 5 which joining the electromagnetic shielding panels 2 together. At the joint of the electromagnetic shielding panels 2, magnetic substances 1 are buried in a row or rows in a part of the metal plate 3 in contact with the coupling piece 5 in parallel with the end of the shielding panel 2 to constitute a magnetic substance row 1. The part where the magnetic substance row 1 is buried is enhanced in equivalent impedance at its surface, so that a high frequency current is prevented from leaking from the contact part.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is designed to eliminate the influence of external electromagnetic waves when experimenting with electronic equipment and electromagnetic machines, and to prevent electromagnetic waves generated by experiments from leaking to the outside. The present invention relates to an electromagnetic shielding room for obtaining a space with sufficient space.

0002

2. Description of the Related Art An electromagnetic shielding room is a closed space constructed of metal plates made of iron, copper, aluminum, etc. so that the indoor and outdoor areas are electromagnetically independent. As shown in FIG. 5, a conventional electromagnetic shielding chamber has a structure in which a plurality of electromagnetic shielding panels 32 made of metal plates or a structure in which metal plates are attached to a core material such as a wood or polymer plate are used to facilitate assembly, as shown in FIG. An electromagnetic shielding chamber 31 constructed by combining electromagnetic shielding panels 32 is used. The structure of the connection part of the electromagnetic shielding panel 32 is such that in order to suppress leakage of electromagnetic waves at the connection part, a plate-shaped panel coupling fitting 5 is attached to the electromagnetic shielding panel 2 made of a core material 4 and a metal plate 3, as shown in FIG. A structure in which the metal surfaces of the electromagnetic shielding panels 12a and 12b are brought into contact and fastened with bolts 6 to conductively connect them, and a structure in which the metal surfaces of the electromagnetic shielding panels 12a and 12b are brought into contact with each other using bolts 14 as shown in FIG. “Electromagnetic interference and prevention measures”, published by Tokyo Denki University Press, and “Fa
cts・and・Myths・of・RF・Shiel
ding”IEEE.International・S
emposium・on・Electromagnet
ic Compatibility 1975).

In an electromagnetic shielding room, leakage of electromagnetic waves from a door provided for the entrance and exit of people, equipment, etc. has a great effect on shielding characteristics. In order to suppress electromagnetic waves leaking from the door, in the prior art, a metal knife edge 22 is provided around the door 25 as shown in FIG.
The shielding chamber wall 24 has a structure in which the metal contact piece 23 provided around the opening of the shielding chamber wall 24 makes contact without any gaps.
r・EMC・and・TEMPEST・Testing
"IEEE. International Sympo
sium・on・Electromagnetic・C
Compatibility, 1975).

0004

[Problem to be solved by the invention] In contact between metals,
Because the resistance value of the contact part is larger than that of the metal part, the high-frequency current induced on the metal surface by electromagnetic waves is not completely reflected, but a portion flows along the contact part on the metal side and reaches the space on the opposite side. . If there is a partially non-contact point, the leakage of high frequency current will increase. This is especially noticeable in the low frequency region for large current, low voltage radiation sources such as loop antennas. This current electromagnetically couples indoors and outdoors, causing leakage electromagnetic waves.

An object of the present invention is to provide an electromagnetic shielding chamber that suppresses such transmitted current and improves the shielding effect of the shielding chamber.

[0006]

[Means for Solving the Problems] In order to achieve the above object, an electromagnetic shielding chamber according to the present invention includes a plurality of electromagnetic shielding panels, a coupling fitting, and a magnetic material. The electromagnetic shielding panels constitute the walls of the electromagnetic shielding room, the coupling fittings cover the butting sides of adjacent electromagnetic shielding panels and connect the panels, and the magnetic material It is interposed between the shielding panel and the coupling fitting to prevent magnetic leakage through the gap.

[0007] Furthermore, the magnetic material is arranged in one or more rows between the electromagnetic shielding panel and the coupling fitting.

The present invention also provides an electromagnetic shielding chamber having a plurality of electromagnetic shielding panels and a magnetic material, wherein the plurality of electromagnetic shielding panels constitute a wall of the electromagnetic shielding chamber, and the end surfaces thereof are connected to each other. They are assembled by butting each other, and the magnetic material is interposed between the butt end faces of adjacent electromagnetic shielding panels to prevent magnetic leakage between the butt end faces.

The present invention also provides an electromagnetic shielding chamber having an opening/closing door, a conductive knife edge, and a magnetic material, wherein the opening/closing door opens and closes an opening in a wall of the shielding chamber constituting the electromagnetic shielding chamber. The conductive knife edge is integrated with the opening/closing door, and when the door is closed, it is inserted between a pair of metal contact pieces provided at the opening in the shielding chamber wall, magnetically sealing the gap between the opening/closing door and the shielding chamber wall. The magnetic material is provided at the contact portion between the knife edge and the metal contact piece to prevent magnetic leakage from the contact portion.

0010

[Effect] At contact points between conductors such as metals, the contact resistance is greater than the surface resistance of the conductors, so the high-frequency current flowing there is not completely reflected, and some of it flows along the contact point, causing leakage. Causes electromagnetic waves. In particular, electromagnetic waves with large magnetic field components tend to induce high-frequency currents, and this tendency is noticeable. In a structure in which a magnetic material is embedded in the contact area between conductors, the contact area is equivalent to a state where an inductance with high impedance is loaded, so the contact resistance between the conductors is relatively low, and high frequency waves leak through the contact area. Current decreases. The purpose of embedding the magnetic material array in the conductive surface is to maintain conductive contact. The higher the magnetic permeability of a magnetic material, the higher the impedance of the conductor surface, so the shielding effect is greater. Furthermore, when a magnetic material with magnetic loss is used, shielding performance is improved by absorbing electromagnetic energy.

[0011]

[Embodiments] Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

(Embodiment 1) FIG. 1 is a cross-sectional view showing the structure of a connecting portion of an electromagnetic shielding panel of an electromagnetic shielding room according to Embodiment 1 of the present invention. In the figure, the electromagnetic shielding panel 2 of this embodiment has a structure in which a core material 4 such as a wooden board is sandwiched between metal plates 3 such as iron or aluminum. The connecting portion of the electromagnetic shielding panel 2 is connected by two plate-shaped coupling fittings 5 that sandwich the electromagnetic shielding panel 2 so as to maintain conductivity. The electromagnetic shielding panel 2 and the coupling fitting 5 are fixed by bolts 6 passing through the coupling fitting 5.

The metal plate 3 has a structure in which a plurality of grooves 3a are provided in a part of the portion that contacts the coupling fitting 5 and a magnetic material is embedded therein to form a magnetic material array 1. As shown in FIG. 2, the magnetic material array 1 may be embedded in a portion of the plate that contacts the metal plate 3 on the coupling fitting 5 side. Alternatively, the magnetic material array 1 may be embedded in the contact portions of both the metal plate 3 and the coupling fitting 5. As the magnetic material constituting the magnetic material array 1, a ferrite sintered body, a polymer material mixed with ferrite powder, a magnetic alloy such as a magnetic amorphous alloy or permalloy, etc. are used. When frequency characteristics are taken into consideration, a NiZn-based ferrite sintered body is suitable because it has a small decrease in magnetic permeability in a high frequency band. In this embodiment, by embedding the magnetic material array 1 in the metal plate 3 or the plate-shaped coupling fitting 5, the impedance of the metal surface is equivalently increased and high frequency current leaking through the contact portion is suppressed.

(Embodiment 2) FIG. 3 is a cross-sectional view showing the structure of a connection part of an electromagnetic shielding panel of an electromagnetic shielding room using Embodiment 2 of the present invention. In this embodiment, the electromagnetic shielding panel 12a is composed of a metal plate, and the electromagnetic shielding panel 1
2a has an end bent at a right angle and is a contact portion 13 for making conductive contact with the adjacent electromagnetic shielding panel 12b.
It constitutes a. A part of the contact parts 13a, 13b has a magnetic material embedded in the contact surface side, and the magnetic material rows 11a,
11b. Both electromagnetic shielding panels 12a
, 12b are the magnetic body rows 11a, 12b of the contact portions 13a, 13b.
It is fixed by a bolt 14 passing through the outside of 11b. The magnetic materials constituting the magnetic material arrays 11a and 11b include ferrite sintered bodies, polymer materials mixed with ferrite powder,
Magnetic alloys such as magnetic amorphous alloys and permalloy are used. When frequency characteristics are taken into consideration, a NiZn-based ferrite sintered body is suitable because it has a small decrease in magnetic permeability in a high frequency band. In FIG. 3, by embedding magnetic material arrays 11a and 11b in contact parts 13a and 13b with adjacent panels, the impedance of the contact parts is increased to suppress leaking high-frequency current.

(Embodiment 3) FIG. 4 is a sectional view showing an electromagnetic shielding structure of an opening of an electromagnetic shielding chamber using Embodiment 3 of the present invention. The fracture surface in this cross-sectional view is a horizontal plane. In this embodiment, as shown in FIG.
3 and is short-circuited with the shielding chamber wall 24. A knife edge 22 is provided at the edge of the door 25. The knife edge 22 has one or more rows of magnetic material rows 21 embedded in the portion that contacts the contact piece 23 in the closed state. Magnetic material row 2
As the magnetic material constituting 1, a ferrite sintered body, a polymer material mixed with ferrite powder, a magnetic alloy such as a magnetic amorphous alloy or permalloy, etc. are used. When frequency characteristics are taken into consideration, a NiZn-based ferrite sintered body is suitable because it has a small decrease in magnetic permeability in a high frequency band. The contact piece 23 is composed of a conductive finger having a spring-like structure or a resilient conductive shielding material such as an EMI gasket. In FIG. 4, by embedding the magnetic material array 21 in the part of the knife edge 22 that contacts the contact piece 23, the impedance of this part is increased and the high frequency current leaking through the contact part between the knife edge 22 and the contact piece 23 is suppressed. suppress.

[0016]

Effects of the Invention As explained above, the electromagnetic shielding chamber of the present invention prevents high frequency current leaking from the connections of the electromagnetic shielding panels constituting the electromagnetic shielding chamber from the contact portion between the electromagnetic shielding panel and the connecting fittings, or the adjacent panel. This can be suppressed by the magnetic material array embedded in the contact portion between the two, which has the effect of improving the shielding performance of the electromagnetic shielding chamber. In addition, the high frequency current leaking from the contact area between the knife edge of the electromagnetic shielding room door and the metal contact piece on the shielding room side can be suppressed by the magnetic material array embedded in the contact area of the knife edge with the metal contact piece. It has the effect of improving the shielding performance of the room.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a connecting portion of an electromagnetic shielding panel according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a connecting portion of an electromagnetic shielding panel according to a first embodiment of the present invention.

FIG. 3 is a sectional view showing a connecting portion of an electromagnetic shielding panel according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing an electromagnetic shielding structure of an opening of an electromagnetic shielding chamber according to a third embodiment of the present invention.

FIG. 5 is a perspective view showing an electromagnetic shielding chamber configured with a plurality of electromagnetic shielding panels.

FIG. 6 is a sectional view showing a connection part of an electromagnetic shielding panel according to the prior art.

FIG. 7 is a sectional view showing a connection part of an electromagnetic shielding panel according to the prior art.

FIG. 8 is a sectional view showing an electromagnetic shielding structure of an opening of an electromagnetic shielding chamber according to the prior art.

[Explanation of symbols]

1 Magnetic material array 2 Electromagnetic shielding panel 3 Metal plate 4 constituting the electromagnetic shielding panel Core material 5 constituting the electromagnetic shielding panel Plate-shaped coupling fitting 6 Bolts 11a, 11b Magnetic material array 12a, 12b Electromagnetic shielding panel 13a, 13b Contact Part 14 Bolt 21 Magnetic material row 22 Metal knife edge 23 Metal contact piece 24 Shielding chamber wall 25 Door

Claims (4)

[Claims] Claim 1: An electromagnetic shielding chamber comprising a plurality of electromagnetic shielding panels, a coupling fitting, and a magnetic material, wherein the plurality of electromagnetic shielding panels constitute a wall of the electromagnetic shielding chamber, and the coupling fittings include a plurality of electromagnetic shielding panels. covers the butted sides of adjacent electromagnetic shielding panels and connects the panels.
An electromagnetic shielding chamber characterized in that a magnetic substance is interposed between an electromagnetic shielding panel and a coupling fitting to prevent magnetic leakage from a gap therebetween. 2. The electromagnetic shielding chamber according to claim 1, wherein the magnetic material is arranged in one or more rows between the electromagnetic shielding panel and the coupling fitting. [Claim 3] An electromagnetic shielding room having a plurality of electromagnetic shielding panels and a magnetic material, wherein the plurality of electromagnetic shielding panels constitute a wall of the electromagnetic shielding room, and are assembled by butting their end faces together. An electromagnetic shielding chamber characterized in that the magnetic material is interposed between abutting end faces of adjacent electromagnetic shielding panels to prevent magnetic leakage from between the abutting end faces. 4. An electromagnetic shielding chamber comprising an opening/closing door, a conductive knife edge, and a magnetic material, wherein the opening/closing door opens and closes an opening in a wall of the shielding chamber constituting the electromagnetic shielding chamber. The knife edge is integrated with the opening/closing door, and is inserted between a pair of metal contact pieces provided at the opening in the shielding chamber wall when the door is closed, magnetically sealing the gap between the opening/closing door and the shielding chamber wall. An electromagnetic shielding chamber, characterized in that the magnetic material is provided at a contact portion between the knife edge and the metal contact piece to prevent magnetic leakage from the contact portion.