JPH01256198A - Electromagnetic wave shield - Google Patents

Abstract

PURPOSE:To minimize decrease of shielding effect by providing one or more cross-shaped or radial cut to a cloth or nonwoven fabric surface of good conductive fiber such as fine metal fiber, metal coated resin fiber and carbon fiber. CONSTITUTION:A cross-shaped cut 2 for cable through is provided to a surface of cloth or nonwoven fabric 1 of conductive fiber such as metal fiber having a diameter of several mum-1mm, carbon fiber and metal coated resin fiber. Usually, edges of the conductive cloth or nonwoven fabric 1 are put in and fixed by a conductive frame 3 of metal, etc., which is made equipotential by use of conductive adhesive, etc. The size of the cut 2 is minimized to allow a connector provided on both edges of a cable 5 passing through. Therefore, clearance at the cut 2 caused by the through cable 5 remains at a small section near the cable 5 due to the flexibility of the conductive cloth or the nonwoven fabric 1. It is also possible to minimize decrease of shield effect even through a cable having a relatively large connector.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic wave shielding body used in a cable penetration opening of a metal casing of an electrical or electronic device.

[Conventional technology]

Various electromagnetic shielding bodies have been developed in the past, but
As shown in Figure 5, most of these are made by integrally molding a plastic material 6 mixed with conductive flakes or powder 7 in order to minimize the transmission of electromagnetic waves, or are made of a housing that constitutes an electronic device. A gas get material was used to reduce leakage at the contact surfaces.

[Problem to be solved by the invention]

However, when configuring a system by connecting devices, it may be necessary to provide an opening in the casing of the device to allow a coaxial cable, bus cable, etc. to pass through. This type of opening can accommodate several types of cables depending on the system configuration, so it is flexible to accommodate any system, and it must be at least larger than the connectors connected to both ends of the cable. Since the diameter is required to be large, the diameter is relatively large.

[Problem to be solved by the invention]

However, this is unfavorable from the standpoint of electrical and electrical shielding, and furthermore, these openings cannot be covered with shielding material, so no countermeasures have been taken to protect against electricity. The use of equipment without countermeasures is likely to cause electromagnetic interference with other equipment, which can interfere with normal operation. Therefore, some type of electromagnetic shielding measure for the essential housing opening has been required.

An object of the present invention is to provide an electromagnetic wave shield for use in an opening for passing cables such as signal cables and bus cables.

[Means to solve the problem]

In order to achieve the above object, the electromagnetic wave shielding body of the present invention uses metal fibers having a diameter of several μm to 111 μm.

One or more cross-shaped or radial cuts are provided on the surface of a cloth or nonwoven fabric made of metal-coated resin fibers, carbon fibers, or other highly conductive fibers.

[Effect]

Cloths or nonwoven fabrics made of metal fibers, carbon fibers, metal-coated resin fibers, etc. are electrically conductive and function as electromagnetic shielding materials. By providing a notch for passing a cable through the surface of the cloth or nonwoven fabric, it becomes an electromagnetic wave shield suitable for an opening for passing a cable. Since the gap created by the cable penetration is limited to a very small area around the cable, the deterioration of the shielding effect can be minimized.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the present invention provides cross-shaped cuts 2 for cable penetration in the fabric surface of a cloth or nonwoven fabric 1 made of conductive fibers such as metal fibers, carbon fibers, or metal-coated resin fibers with a diameter of several μm to 100 μm. Normally, a conductive cloth or a non-woven cloth 1 is sandwiched at its edges and fixed by a conductive frame 3 made of metal or the like which is brought into an equipotential state using means such as a conductive adhesive. The size of the notches 2 is the minimum size that allows the connectors provided at both ends of the cables to pass therethrough, and the number thereof is equal to the maximum number of cables that can pass through the opening where the electromagnetic shielding body is attached.

Figure 2 shows the electromagnetic wave shielding body according to the present invention in an electronic separate device housing 4.
It is a figure attached to the opening for cable penetration of. The metal casing 4 and the conductive frame 3 are screwed together.

It is fixed by crimping or the like while maintaining conductivity, and in this state it suppresses electromagnetic waves leaking through the opening. A cable 5 for connecting to an external device can be passed through the notch 2, pulled out from the housing 4, and connected to other devices. Due to the flexibility of the conductive fabric or nonwoven fabric 1, the gap created in the notch 2 when the cable 5 penetrates remains in a small area near the cable, so even when a cable with a relatively large connector is passed through, the reduction in shielding effect is kept small. It will be done. When the notches 2 are formed radially in the cloth surface as shown in FIG. 3(a), the gap when the cable 5 is passed through becomes even smaller, and a high electromagnetic shielding effect is ensured. In addition, when the connector has an elongated shape such as a bus cable, a large number of horizontal notches are formed to intersect with the vertically long notches as shown in Figure 3(b) for cable insertion. This is dealt with by making a bony cut 2.

In order to simplify the structure in any of the above cases, the conductive frame 3 is removed and the conductive fabric or non-woven fabric 1 is
It is also possible to directly fix the cloth edge around the opening of the metal casing 4. At this time, it is necessary to always keep the conductive cloth or nonwoven fabric 1 and the metal casing 4 in a state of equal potential by using means such as screwing or conductive adhesive as in FIG. 1.

〔Effect of the invention〕

As described above, the present invention has the effect of realizing an effective electromagnetic wave shield for an opening for passing a cable.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of an electromagnetic wave shield according to the present invention, FIG. 2 is a perspective view showing the electromagnetic wave shield according to the present invention installed in a cable penetration opening of a metal casing, and FIG. Figures (a) and (b) are diagrams showing the shape of the notches provided in the present electromagnetic shielding body, Figure 4 is a perspective view of the electromagnetic shielding body with a simplified structure, and Figure 5 is a diagram showing the electromagnetic shielding body according to the prior art. It is a perspective view of a body. 1... Conductive cloth or non-woven fabric 2... Notch for cable penetration 3... Conductive frame 4... Metal casing of the device 5... Cable patent applicant NEC Corporation Agent Patent attorney Inner original sound Figure 1 Figure 2 Illustration 3 (1)) Figure 4 Figure 5

Claims (1)

[Claims] 1. An electromagnetic shielding body characterized by having one or more cross-shaped or radial cuts formed on the surface of a cloth or nonwoven fabric made of highly conductive fibers such as metal fibers, metal-coated resin fibers, and carbon fibers having a diameter of μm to 1 mm.