JPH1187989A - Shield - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance shielding characteristics by arranging a plurality of thin magnetic bands made of an amorphous alloy or a nano-crystal alloy in parallel, while overlapping the end part thereof partially, and integrating them with resin and then arranging a conductor on one side. SOLUTION: A thin amorphous magnetic body is produced by liquid quenching method, e.g. single roll method, and heat treated at a temperature of crystallization point or above, thus microcrystallizing the thin amorphous magnetic body. In order to magnetically and electrically couple the thin magnetic band of amorphous alloy or nano-crystal alloy thus produced, a plurality of rows of thin magnetic bands are arranged in parallel, while overlapping the end part thereof partially and a resin sheet is bonded to one end thereof. Furthermore, a conductor of copper or aluminum is arranged on one side of the sheet. According to the arrangement, magnetic shielding and electromagnetic shielding characteristics can be exhibited sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shield member that can be used as a magnetic shield and an electromagnetic wave shield used in electronic equipment and the like.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become more sophisticated and have been used in large numbers, malfunctions of the devices due to leakage magnetic fields, electromagnetic noise, and the like have become a problem. It is known that iron foil or permalloy is effective as a shielding material for preventing this. This utilizes the magnetic permeability of the soft magnetic material, and the larger the value, the higher the effect. On the other hand, a larger magnetic shielding effect can be obtained by using an amorphous material for the soft magnetic material, as disclosed in JP-A-52-10660 and JP-A-55-2119.
No. 6, etc. In Japanese Patent Publication No. 4-4393, a nanocrystalline alloy represented by Fe-Cu-Nb-Si-B system shows excellent soft magnetism and shows little change with time, so that it is suitable for a shielding material or the like. ing.

As described in Japanese Patent Publication No. 2591586 or 2591585, the end faces of amorphous ribbons arranged in parallel with each other are secured to each other to secure a flat area, and a metal foil such as copper is laminated. Shielding materials have also been proposed.

[0004]

Since amorphous alloys and nanocrystalline alloys are manufactured in the form of ribbons or powders, a large-area shield member cannot be directly obtained as it is. As a technique for increasing the area, there are a method of arranging the ribbons in parallel and a method of solidifying the powder with a resin and forming the sheet into a sheet. However, the method of molding with powder and resin is based on the fact that the magnetic material is granulated,
The effect of the demagnetizing field on each particle increases, and the magnetic shielding properties are not sufficient.

In the method of arranging the ribbons in parallel, the ribbons aligned in parallel hardly contact each other because the dimensional accuracy of the width of the ribbon and the end face of the ribbon are not completely vertical. Since the magnetic or electrical connection between the ribbons is weak, there is a problem that a sufficient shielding effect cannot be obtained. SUMMARY OF THE INVENTION An object of the present invention is to provide a shield member having a new configuration capable of sufficiently exhibiting the shielding characteristics of amorphous and nanocrystalline alloys in view of the above-mentioned problems.

[0006]

SUMMARY OF THE INVENTION The present inventor has proposed that a ribbon-shaped amorphous or nanocrystalline alloy arranged in parallel should not be simply joined but partially overlapped, and then integrated with a resin. The present inventors have found that it is possible to improve the shield characteristics deteriorated due to a magnetic or electric gap generated by a gap existing therebetween, and reached the present invention.

That is, according to the present invention, a plurality of magnetic ribbons made of an amorphous alloy or a nanocrystalline alloy are partially overlapped at their ends, arranged in parallel, and integrated with a resin, and at least one of them. A shield member comprising a conductor.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, one of the important features of the present invention is that ribbons are overlapped. The stacked ribbons are in magnetic and electrical contact. Therefore, the magnetic shield and the electromagnetic shield have an advantage that the leaked portion of the captured magnetic flux or electromagnetic wave is eliminated. In particular, amorphous and nanocrystalline materials, which are thin ribbons of 100 μm or less, are difficult to secure an effective cross-sectional area through which magnetic flux can pass as a shield in magnetic shielding applications, and magnetic flux easily leaks when there is a space. The presence of the part is necessary. Note that, as a superposition form, as shown in FIG. 2, when superimposed in a wave shape, the ribbons are easily arranged in order from one direction. FIG.
As shown in FIG.

Further, in the present invention, the resin is integrated. For thin ribbons of 100 μm or less, polyethylene terephthalate (PET)
By covering with a plastic resin such as
Steps of superposition can be reduced, and sufficient flexibility can be obtained. Of course, an adhesive may be interposed between the magnetic ribbon and the resin. Also, the thickness of the resin used in the present invention,
In order to ensure flexibility, it is preferable that the thickness is 500 μm or less.
It is desirable that the thickness be larger than the thickness of the magnetic ribbon.

[0010] The nanocrystalline material referred to in the present invention is a material substantially composed of fine crystals of 100 nm or less. Specifically, it is a material composed of fine crystals of bccFe represented by the Fe-Cu-Nb-Si-B system. Since such a nanocrystalline material is crystallized by heat treatment,
There is a problem that it is more brittle than an amorphous material and is difficult to handle. By integrating with a resin as in the present invention, flexibility can be given to the nanocrystalline material, and handling such as bending as a shielding material can be improved.

The shield member of the present invention can be manufactured by the following method. First, an amorphous ribbon is produced by a liquid quenching method such as a single roll method. Next, the amorphous alloy can be used as it is, but it may be heat-treated at a temperature lower than the crystallization temperature to obtain better soft magnetism. On the other hand, in the case of a nanocrystalline material, after forming an amorphous ribbon, it is heat-treated at a crystallization temperature or higher to microcrystallize. In order to magnetically and electrically couple the magnetic ribbons of the amorphous alloy or the nanocrystalline alloy obtained in this way, the ends are partially overlapped, and a plurality of strips are arranged in parallel, and at least one of them is made of resin. Adhesive sheets. Further, in the present invention, the resin does not need to be a single layer, and the resin may be multi-layered such as a combination of a resin serving as an adhesive and a resin for reinforcement.

Another important feature of the present invention is the placement of a conductor such as copper or aluminum on at least one side of the sheet. This is because the electric resistance of the amorphous alloy or the nanocrystalline alloy is large, and it may be difficult to obtain a sufficient shielding effect with respect to electromagnetic waves in a high frequency band using only the above-described magnetic ribbon. Therefore, in the present invention, the magnetic shield characteristics and the electromagnetic shield characteristics are further enhanced by combining a good conductor having excellent electromagnetic shield characteristics in a high frequency band. Further, the thickness of the conductor used in the present invention is preferably 200 μm or less in order to ensure flexibility.

[0013]

【Example】

(Example 1) Width 25mm, thickness 20μ by single roll method
m ₁ of Cu ₁ —Nb ₃ —Si ₁₅ —B ₆ (at%), balance Fe
An amorphous ribbon consisting of 550 ° C.
For 1 hour to obtain a nanocrystalline ribbon made of fine crystals of bccFe of 100 nm or less. Then, as shown in FIG. 2, a plurality of layers are superposed and arranged in parallel so as to be magnetically and electrically connected, and a resin sheet made of vinyl chloride having a thickness of 75 μm is adhered to one entire surface using an adhesive. ,
A wide copper foil having a thickness of 35 μm was adhered so as to cover the entire other surface, thereby producing a sheet serving as a shield member having a size of 300 mm × 300 mm. FIG. 1 shows a schematic view of the cross-sectional structure of this sheet. 33m inside diameter from this sheet
m, a ring sample having an outer diameter of 45 mm was sampled, and the initial magnetic permeability in a main frequency band of 50 Hz to 10 kHz of the magnetic shield material was measured.

As a comparative example, the nanocrystalline material ribbons of the above-described embodiment were used, and a plurality of strips were arranged in parallel as shown in FIG. 4, and an adhesive was used in the same manner as in the embodiment. A 75 μm thick vinyl chloride sheet is adhered, and a wide thickness 35 μm is covered so as to cover the entire other surface.
m of copper foil was adhered to prepare a sheet having a size of 300 mm × 300 mm. A similar ring sample was taken from this sheet and the initial magnetic permeability was measured. In both the examples and the comparative examples, when a DC magnetic field of 1 G was applied to the 300 mm × 300 mm sheet using a coil, the leakage magnetic flux generated at the joint was measured using a Gauss meter. The results are shown in Table 1. Furthermore, by the transfer impedance method,
FIG. 5 shows the results of measuring the electromagnetic wave shielding effect from 1 MHz to 1 GHz.

[0015]

[Table 1]

As is apparent from Table 1, the shield member of the present invention has a higher magnetic permeability and a lower leakage magnetic flux than the comparative example by forming the overlapping portion, and is excellent as a magnetic shield material. It became something. In addition, FIG. 5 shows that the product of the present invention was also excellent as an electromagnetic wave shielding material as compared with the comparative example. In addition, it was confirmed that the shield member of the present invention was an integrated sheet electrically connected by the overlapping portion. The shield member according to the present invention can be bent or cut. If an adhesive layer is provided on the surface as needed, it can be easily attached to a device or the like at a necessary place such as an electronic device.

(Example 2) Width 25m by single roll method
m, 25 μm thick Fe ₂ —Mn ₂ —Cr ₃ —Si ₁₃ —B ₉
(At%), an amorphous ribbon consisting of the balance Co was prepared and heat-treated at 450 ° C. for 1 hour. As shown in FIG. 2, a plurality of layers are arranged in parallel so as to be magnetically and electrically coupled, the above-mentioned polyethylene terephthalate is adhered to one surface thereof, and a wide thickness 3 is applied so as to cover the entire other surface.
An aluminum foil of 5 μm was adhered to prepare a sheet serving as a shield member having a size of 400 mm × 800 mm. A ring sample having an inner diameter of 33 mm and an outer diameter of 45 mm was collected from this sheet, and the initial permeability at a frequency of 50 Hz to 10 kHz was measured.

As a comparative example, the amorphous ribbon of the above-described embodiment was used, a plurality of strips were arranged in parallel as shown in FIG. 4, an adhesive was used in the same manner as in the above-described embodiment, polyethylene terephthalate was used on one side, and A wide aluminum foil having a thickness of 35 μm is stuck so as to cover the entire surface of the sheet, a sheet having a size of 400 mm × 800 mm is prepared, and a similar ring sample is collected.
The initial permeability at kHz was measured. In each of the examples and comparative examples, the leakage magnetic flux generated at the joint when the DC magnetic field generated by the coil was applied was measured. Table 2 shows the results
It appends to. Further, by the transfer impedance method, 1
FIG. 6 shows the results of measuring the electromagnetic wave shielding effect from MHz to 1 GHz.

[0019]

[Table 2]

As is clear from Table 2, the shield member using the amorphous material of the present invention has an excellent initial magnetic permeability, although slightly inferior to the nanocrystalline material of Example 1, by forming the overlapping portion. Has low leakage magnetic flux,
It became an excellent magnetic shield material. Further FIG.
Therefore, it became an excellent electromagnetic shielding material. In addition, it was confirmed that the shield member of the present invention was an integrated sheet electrically connected by the overlapping portion.

As described above, the shielding material of the present invention using an amorphous material has a high magnetic permeability and a low leakage magnetic flux, as well as an electrically integrated structure, as in the case of using the above-described nanocrystalline material. Therefore, the magnetic shield and the electromagnetic wave shield characteristics are excellent as compared with the comparative example.
Further, the shield member according to the present invention can be bent or cut. If an adhesive layer is provided on the surface as needed, it can be easily attached to a device or the like at a necessary place such as an electronic device.

[0022]

According to the present invention, it is possible to provide a shield member having a new structure capable of sufficiently exhibiting the shielding characteristics of amorphous and nanocrystalline materials by forming an overlapped portion. large.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a configuration of a shield member of the present invention.

FIG. 2 is a view showing an example of an overlapping portion of the shield member of the present invention.

FIG. 3 is a view showing another example of the overlapping portion of the shield member of the present invention.

FIG. 4 is a diagram illustrating a configuration example of a shield member of a comparative example.

FIG. 5 is a diagram showing examples of the present invention and comparative examples.

FIG. 6 is a diagram showing examples of the present invention and comparative examples.

Claims (1)

[Claims] A plurality of magnetic ribbons made of an amorphous alloy or a nanocrystalline alloy are partially overlapped at their ends, arranged in parallel, integrated with a resin, and integrated with a resin. A shield member having a conductor disposed thereon.