JP2012151242A - Electromagnetic noise countermeasure member and electromagnetic noise countermeasure method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic noise countermeasure member which is used in a manner that achieves full performance even though either of magnetic field suppression effect and transmission loss effect is demanded, and to provide an electromagnetic noise countermeasure method using the electromagnetic noise countermeasure member.SOLUTION: In an electromagnetic noise suppression sheet 1, a magnetic layer 2, an adhesion layer 3, and a conductive layer 4 are layered in this order, and at least part of the adhesion layer 3 is formed at the outer side of outer peripheries of the magnetic layer 2 and the conductive layer 4. The electromagnetic noise suppression sheet 1 is installed (bonded) so that the magnetic layer 2 contacts with an electromagnetic noise generation source or the conductive layer 4 contacts with the electromagnetic noise generation source. Thus, the electromagnetic noise suppression sheet 1 fully achieves desired effect (magnetic field suppression effect and transmission loss effect) according to an object.

Description

  The present invention relates to an electromagnetic noise countermeasure member such as an electromagnetic noise suppression sheet, and an electromagnetic noise countermeasure method for transmission lines and electronic components.

  Conventionally, in order to suppress electromagnetic noise of a signal transmitted in an electronic device, there has been widely used a method of arranging an electromagnetic noise countermeasure member (electromagnetic noise suppression sheet, composite magnetic sheet, etc.) in the vicinity of a circuit or around a transmission line. It is used. Such an electromagnetic noise countermeasure member controls and absorbs electromagnetic noise in the MHz band, for example, by controlling the target electromagnetic noise mainly based on the magnetic permeability of magnetic particles or the like.

  When such an electromagnetic noise countermeasure member is used in a mobile phone or the like, the electromagnetic field confinement effect suppresses inductive coupling to signal lines in the device and opposing lines due to high-frequency magnetic field components generated from integrated circuits (ICs). (Magnetic field suppression effect). Further, by applying an electromagnetic noise countermeasure member to the signal line extending from the IC or the like, the high frequency component due to the effect of adding impedance to the signal line is suppressed (filter effect). Furthermore, by using an electromagnetic noise countermeasure member for a flexible cable or the like connecting a high-speed circuit, a common mode current component superimposed on the cable is suppressed (transmission loss effect).

  In recent years, electronic circuit design has become more and more diversified, and the frequency of electromagnetic noise that should be suppressed according to the combination of electronic components and transmission signals has also diversified and wideband (for example, in the order of MHz to GHz). A very wide frequency range).

  For this reason, the electromagnetic noise countermeasure member is also required to have a wider band. In order to cope with this, for example, Patent Document 1 proposes a communication improving sheet body in which an adhesive layer, a conductive layer, and a magnetic layer are laminated in this order. Patent Document 2 proposes a composite magnetic member in which an adhesive layer, a magnetic layer, and a conductive layer are laminated in this order. These conventional electromagnetic noise countermeasure members can suppress and absorb electromagnetic noise having a wide band mainly by controlling the magnetic permeability and dielectric constant of magnetic particles and the like.

JP 2007-143132 A JP 2008-124197 A

  However, when the present inventors evaluated the effect of electromagnetic noise in a high frequency band using the electromagnetic noise countermeasure members described in Patent Documents 1 and 2 above, these are the so-called magnetic field suppression effect and transmission loss. It has been found that the configuration optimized for only one of the effects is employed, and the tolerance (selectivity) for the other effect (magnetic field suppression effect or transmission loss effect) is poor.

  Therefore, the present invention has been made in view of such circumstances, and an electromagnetic noise countermeasure member that can be used in a mode that can sufficiently exhibit its performance regardless of whether a magnetic field suppression effect or a transmission loss effect is required, and An object of the present invention is to provide a method for countermeasures against electromagnetic noise using the.

  In order to solve the above-described problem, an electromagnetic noise countermeasure member according to the present invention includes a magnetic layer, an adhesive layer, and a conductive layer laminated in this order, and at least a part of the adhesive layer is an outer periphery of the magnetic layer and the conductive layer. It is formed outside.

  The electromagnetic noise countermeasure member having such a structure is formed such that a magnetic layer and a conductive layer are laminated via an adhesive layer, and at least a part of the adhesive layer protrudes from the outer periphery of the magnetic layer and the conductive layer. Therefore, it can be installed (adhered) to an electromagnetic noise generation source (object, adherend) using the magnetic layer side as a contact surface or the conductive layer side as a contact surface. Here, according to the knowledge of the present inventors, it was found that the magnetic field suppression effect and transmission loss effect against electromagnetic noise strongly correlate with the stacking order of the magnetic layer and the conductive layer. That is, in order to sufficiently suppress the magnetic field strength against electromagnetic noise in the GHz band, the electromagnetic noise suppression sheet in which the magnetic layer is in contact with the electromagnetic noise generation source is more effective in suppressing the electromagnetic noise in which the conductive layer is in contact with the electromagnetic noise generation source. It has been confirmed that it is useful compared to a sheet. On the other hand, in order to sufficiently enhance the transmission loss effect for electromagnetic noise in the GHz band, the electromagnetic noise suppression sheet in which the conductive layer is in contact with the electromagnetic noise generation source is more effective in suppressing the electromagnetic noise in which the magnetic layer is in contact with the electromagnetic noise generation source. It has been confirmed that it is useful compared to a sheet. Therefore, in applications where a magnetic field suppression effect is required, the magnetic layer of the electromagnetic noise countermeasure member of the present invention is installed so as to contact the electromagnetic noise source, and in applications where a transmission loss effect is required. By installing the conductive layer of the electromagnetic noise countermeasure member of the invention in contact with the electromagnetic noise generation source, the performance can be sufficiently exhibited. Moreover, since the electromagnetic noise countermeasure member of the present invention employs a configuration in which a magnetic layer and a conductive layer are laminated via an adhesive layer, a plurality of adhesive layers are not essential. Therefore, the electromagnetic noise countermeasure member of the present invention has a configuration as compared with the electromagnetic noise countermeasure member described in Patent Documents 1 and 2 in which an additional adhesive layer is provided on the outermost layer so that both surfaces can be bonded. It is simple and productivity and economy are improved.

  Moreover, in the said structure, it is preferable that an adhesion layer has a hole in the plane center substantially. If comprised in this way, cost reduction can be achieved.

  Furthermore, each of the magnetic layer and the conductive layer is preferably composed of a plurality of small pieces. If comprised in this way, according to the target object at the time of installation, since the electromagnetic noise countermeasure member can be processed by a small piece unit, the workability at the time of installation can be improved.

  Moreover, the electromagnetic noise countermeasure method of the present invention can effectively use the electromagnetic noise countermeasure member of the present invention, and a magnetic layer, an adhesive layer, and a conductive layer are laminated in this order, and the adhesive layer At least a part of the method includes a step of installing an electromagnetic noise countermeasure member formed outside the outer periphery of the magnetic layer and the conductive layer on the electromagnetic noise generation source.

  ADVANTAGE OF THE INVENTION According to this invention, the electromagnetic noise countermeasure member excellent in versatility which can be used in the aspect which can fully exhibit the performance even if any of the magnetic field suppression effect and the transmission loss effect is requested | required is realized. The effect, productivity and economy can be improved.

It is a model perspective view which shows roughly the electromagnetic noise suppression sheet | seat of 1st Embodiment. It is a schematic cross section along the II-II line of FIG. It is a perspective view which shows roughly the state which is measuring the magnetic field intensity. It is a graph which shows the result of having measured the magnetic field suppression effect with respect to the frequency of an input signal in the electromagnetic noise suppression sheet | seat which made the magnetic layer or the conductive layer the contact surface. It is a perspective view which shows roughly the state which is measuring the transmission loss effect. It is a graph which shows the result of having measured the transmission loss effect with respect to the frequency of an input signal in the electromagnetic noise suppression sheet | seat which made the magnetic layer or the conductive layer the contact surface. It is a model perspective view which shows schematically the electromagnetic noise suppression sheet | seat of 2nd Embodiment. It is a model top view which shows roughly the electromagnetic noise suppression sheet | seat of 3rd Embodiment. It is a schematic cross section which follows the IX-IX line of FIG. It is a model side view which shows roughly the electromagnetic noise suppression sheet | seat of 4th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios. Further, the following embodiments are exemplifications for explaining the present invention, and are not intended to limit the present invention only to the embodiments. Furthermore, the present invention can be variously modified without departing from the gist thereof.

(First embodiment)
FIG. 1 is a schematic perspective view schematically showing an electromagnetic noise suppression sheet 1 of the first embodiment, and FIG. 2 is a schematic cross-sectional view taken along the line II-II in FIG.

  The electromagnetic noise suppression sheet 1 of the present embodiment is obtained by laminating a magnetic layer 2, an adhesive layer 3, and a conductive layer 4 in this order, and one adhesive layer 3 is composed of the magnetic layer 2 and the conductive layer 4. Between the two. In the present embodiment, the magnetic layer 2 and the conductive layer 4 are formed to have substantially the same outer shape so as to overlap in a plan view. Further, the adhesive layer 3 is formed wider than the magnetic layer 2 and the conductive layer 4, whereby a part of the adhesive layer 3 protrudes outward from the outer periphery of the magnetic layer 2 and the conductive layer 4. ing.

  The magnetic layer 2 contains at least a binder 20 and a magnetic material 21. The magnetic layer 2 is obtained by dispersing a magnetic material 21 in a binder 20 and is formed in a substantially rectangular shape (square shape) in plan view in the present embodiment.

  Any known binder can be used as long as it can disperse the magnetic material 21, and is not particularly limited. Specific examples of the binder 20 include, for example, (meth) acrylic resin, polyester resin, polyethylene resin, polystyrene resin, vinyl chloride resin, chlorinated polyethylene resin, polyvinyl acetate resin, polyamide resin, Various resins such as thermoplastic resins such as polyolefin resins, thermosetting resins such as phenol resins, epoxy resins, silicone resins, and melamine resins, natural rubber, chloroprene rubber, butadiene rubber, styrene Various rubbers including butadiene rubber, isoprene rubber, silicone rubber, ethylene propylene rubber, chlorosulfonated rubber, nitrile rubber, acrylonitrile butadiene rubber, (meth) acrylic rubber, polyurethane rubber, etc., olefin elastomer , Styrenic elastomer , Styrene-butadiene elastomers, polyamide elastomers, and thermoplastic elastomers such as polyester elastomers.

  As the magnetic material 21, any known material can be appropriately used as long as it has magnetism. Although not particularly limited, the magnetic material 21 may be a soft magnetic powder from the viewpoint of attenuation of electromagnetic noise and flame retardancy in a high frequency band. preferable. Specific examples of the magnetic material 21 include, for example, Fe, Fe-Si alloy, Fe-Si-Al alloy, Fe-Si-Al-Ni alloy, Fe-Si-Cr alloy, Fe-Si-Cr-Ni alloy, And Fe-based crystal powder such as Fe—Ni alloy, amorphous powder, and various ferrites such as Mn—Zn ferrite, Cu—Zn ferrite, and Mg—Zn ferrite. Among these, an Fe—Si—Al alloy is preferable from the viewpoint of securing high magnetic permeability, and a so-called sendust composition is more preferable. As Fe-Si-Al alloy powder of a sendust composition, what is described in Unexamined-Japanese-Patent No. 2009-262960 is illustrated, for example. The dimensional shape of the magnetic material 21 is not particularly limited, but is preferably a flat shape from the viewpoint of increasing the magnetic permeability.

  The thickness of the magnetic layer 2 is not particularly limited and can be set as appropriate. Specifically, the thickness of the magnetic layer 2 is usually preferably about 10 to 1000 μm, more preferably about 100 to 300 μm.

  The adhesive layer 3 includes a base material 31 and adhesive materials 30 and 32 having adhesiveness, and has adhesive surfaces made of the adhesive materials 30 and 32 on both surfaces of the base material 31 in the stacking direction. The magnetic layer 2 is adhered to the adhesive surface on the upper surface side of the adhesive layer 3, and the conductive layer 4 is adhered to the adhesive surface on the lower surface side. In the present embodiment, the adhesive layer 3 is formed in a substantially rectangular shape (square shape) larger than the magnetic layer 2 and the conductive layer 4 in plan view.

  As the base material 31, a known material can be appropriately used as long as it can support the adhesive materials 30 and 32, and is not particularly limited. Specific examples of the substrate 31 include paper, plastic, and nonwoven fabric. From the viewpoint of providing flexibility or flexibility, the base material 31 is preferably a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, and polyimide, and polyethylene terephthalate is more preferable from the viewpoint of processability and heat shrinkability of the film surface. preferable.

  As the adhesive materials 30 and 32, known materials can be appropriately used as long as they can adhere to the magnetic layer 2 and the conductive layer 4, and are not particularly limited. Specific examples of the adhesive materials 30 and 32 include, for example, thermosetting resins such as urea, melamine, phenol, epoxy, polyurethane, and polyester, vinyl acetate, polyvinyl alcohol, vinyl chloride, In addition to (meth) acrylic and polyethylene-based thermoplastic resins, chloroprene rubber, and elastomers such as silicone rubber, mixtures thereof such as mixtures of epoxy resins and phenolic resins, phenolic resins and chloroprene Examples thereof include a mixture of an elastomer, a mixture of an epoxy resin and a polyamide resin, a mixture of an epoxy resin and a nylon resin.

  In addition, the adhesion layer 3 may contain the magnetic material 21 contained in the magnetic layer 2, the conductive material 41 contained in the electroconductive layer 4 mentioned later, or the powder which improves thermal conductivity. Further, the adhesive layer 3 may be formed (molded) only with the adhesive materials 30 and 32 without using the base material 31.

  The thickness of the adhesive layer 3 is not particularly limited and can be set as appropriate. Specifically, the thickness of the adhesive layer 3 is usually preferably about 5 to 1000 μm, more preferably about 10 to 100 μm.

  The conductive layer 4 contains at least a binder 40 and a conductive material 41. The conductive layer 4 is obtained by dispersing a conductive material 41 in a binder 40. In the present embodiment, the conductive layer 4 is formed in a substantially rectangular shape (square shape) that is substantially the same shape as the magnetic layer 2 in plan view.

  Any known binder can be used as long as it can disperse the conductive material 41 and is not particularly limited. Specific examples of the binder 40 include, for example, (meth) acrylic resins, polyester resins, polyethylene resins, polystyrene resins, vinyl chloride resins, chlorinated polyethylene resins, polyvinyl acetate resins, polyamide resins, Various resins such as thermoplastic resins such as polyolefin resins, thermosetting resins such as phenol resins, epoxy resins, silicone resins, and melamine resins, natural rubber, chloroprene rubber, butadiene rubber, styrene Various rubbers including butadiene rubber, isoprene rubber, silicone rubber, ethylene propylene rubber, chlorosulfonated rubber, nitrile rubber, acrylonitrile butadiene rubber, (meth) acrylic rubber, polyurethane rubber, etc., olefin elastomer , Styrenic elastomer , Styrene-butadiene elastomers, polyamide elastomers, and thermoplastic elastomers such as polyester elastomers.

  As the conductive material 41, any known material can be appropriately used as long as it has conductivity, and is not particularly limited. Specific examples of the conductive material 41 include, for example, metals such as Fe, Al, Cu, Ag, Au, or metal powders composed of alloys, metal nitrides, or metal oxides, carbon nanotubes, carbon black, fullerenes. , Carbon-based materials such as graphene, carbon fiber, graphite, and carbon coil. Among these, from the viewpoints of preventing unwanted radiation and promoting heat diffusion, the conductive material 41 is a carbon-based material such as carbon nanotube, carbon black, fullerene, graphene, carbon fiber, graphite, and carbon coil. It is preferable.

  The thickness of the conductive layer 4 is not particularly limited, and can be set as appropriate. Specifically, the thickness of the conductive layer 4 is usually preferably about 10 to 1000 μm, more preferably about 100 to 300 μm.

  In the electromagnetic noise suppression sheet 1 of the present embodiment, at least one of the adhesive layers 3 is used to be able to adhere to an electromagnetic noise generation source with the magnetic layer 2 side as a contact surface or the conductive layer side 3 as a contact surface. It is necessary that the portion protrudes outward from the outer periphery of the magnetic layer 2 and the conductive layer 4. In the present embodiment, the magnetic layer 2 and the conductive layer 4 are formed in a square shape having a length of 20 mm × width of 20 mm × thickness of 0.2 mm, and the adhesive layer 3 is formed in a square shape of length 25 mm × width 25 mm × thickness 0.05 mm. Is formed. The longer the length of the portion from which the adhesive layer 3 protrudes and the larger the area from which the adhesive layer 3 protrudes, the higher the adhesiveness to the electromagnetic noise source. Therefore, the length of the protruding portion of the adhesive layer 3 needs to be longer than the thickness of the magnetic layer 2 and the conductive layer 4. At least one of the length and width of the adhesive layer 3 is preferably 110% or more, more preferably 120% or more, and still more preferably 125% with respect to the length and width of the magnetic layer 2 and the conductive layer 4. That's it.

The surface resistivity of the electromagnetic noise suppression sheet 1 is preferably 10 ⁶ to 10 ¹² Ω / □ in the magnetic layer 2, more preferably 10 ⁸ to 10 ¹¹ Ω / □, and 10 in the conductive layer 4. ⁻¹ to 10 ³ Ω / □ is preferable, and 10 ⁰ to 10 ² Ω / □ is more preferable. Moreover, it is preferable that the heat conductivity of the electromagnetic noise suppression sheet | seat 1 is 1-500 W / m * K, More preferably, it is 10-300 W / m * K.

  Here, when the inventors evaluated the frequency characteristics regarding the effect of electromagnetic noise using the electromagnetic noise suppression sheet 1 described above, the magnetic layer 2 or the conductive layer 4 was used as the contact surface with respect to the electromagnetic noise generation source. In this case, it has been found that the effective effect on electromagnetic noise in the high frequency band is different. Details will be described below.

(1) First Frequency Characteristic Test FIG. 3 is a perspective view schematically showing a state in which the magnetic field strength ΔH is being measured. In the figure, a microstrip line (MSL; for example, characteristic impedance 50Ω; width 30 mm × length 140 mm) is formed on the base sheet B, one end T of which is terminated at 50Ω, and the other end An input signal line Ls connected to the network analyzer N is connected to S. Further, the central part of the extending direction of the microstrip line (MSL) is covered with an electromagnetic noise suppression sheet 1 (width 50 mm × length 25 mm) which is an electromagnetic noise countermeasure member according to the present invention, and the electromagnetic noise suppression sheet. 1 above 1 mm, the magnetic field probe MFP is installed.

  This magnetic field probe MFP is connected to the network analyzer N via a measurement signal line Lm. The network analyzer N serves as, for example, a signal generator and a spectrum analyzer. In the state shown in FIG. 3, an input signal of 0 dB is input from the network analyzer N to the other end S of the microstrip line (MSL). The network analyzer N measures the output voltage Vs of the magnetic field probe MFP. Next, the output voltage V0 of the magnetic field probe MFP is measured with the network analyzer N in the same manner as above except that the electromagnetic noise suppression sheet 1 is not used, that is, the microstrip line MSL is not covered with the electromagnetic noise suppression sheet 11. To do.

  In the magnetic field strength measurement method, the magnetic field probe MFP evaluates how much the magnetic field strength ΔH on the microstrip line MSL can be suppressed by using the electromagnetic noise suppression sheet 1. A smaller magnetic field strength ΔH indicates a higher magnetic field suppression effect.

The magnetic field strength ΔH is calculated from the following formula (1).
ΔH = 20 × log (H _NSS / H ₀ ) (1)
In the equation, H _NSS indicates the magnetic field strength when the electromagnetic noise countermeasure member is used in the magnetic field strength measurement method, and H ₀ indicates the magnetic field strength when the electromagnetic noise countermeasure member is not used in the measurement method. .

Then, the above equation (1) can be developed as represented by the following equation (2). Even if the antenna coefficient AF of the magnetic field probe MFP is unknown, the output voltage Vs, V0 of the magnetic field probe MFP is ΔH can be calculated.
ΔH = 20 × log (H _NSS / H ₀ ) = 20 × log {(AF · Vs) / (AF · V0)} (2)

  FIG. 4 is a graph showing the results of measuring the magnetic field suppression effect on the frequency of the input signal in the electromagnetic noise suppression sheet 1 with the magnetic layer 2 or the conductive layer 4 as the contact surface. Plots with circles (◯) are results of measuring the magnetic field suppression effect using the electromagnetic noise suppression sheet 1 with the conductor layer 4 as the contact surface. The plots with squares (□) are the results of measuring the magnetic field suppression effect using the electromagnetic noise suppression sheet 1 with the magnetic layer 2 as the contact surface.

  As shown in FIG. 4, it was found that the effect of suppressing the magnetic field strength ΔH differs depending on which of the magnetic layer 2 and the conductive layer 4 is used as the contact surface. More specifically, the electromagnetic noise suppression sheet 1 with the magnetic layer 2 as the contact surface has a higher frequency band of 1 GHz to 6 GHz than the electromagnetic noise suppression sheet 1 with the conductive layer 4 as the contact surface. It was confirmed that the magnetic field intensity ΔH against electromagnetic noise was suppressed. As a result, the electromagnetic noise suppression sheet 1 with the magnetic layer 2 as the contact surface can obtain a higher magnetic field suppression effect than the electromagnetic noise suppression sheet 1 with the conductive layer 4 as the contact surface. found.

(2) Second Frequency Characteristic Test FIG. 5 is a perspective view schematically showing a state in which a transmission loss effect is being measured. In the figure, a coaxial tube C is arranged, one end V of which is connected to an input signal line Li connected to the network analyzer N, and the other end W is connected to the network analyzer N. An output signal line Lo is connected. The coaxial pipe C is formed with a central conductor (diameter 16.9 mm, length 200 mm) Cc along the extending direction in the coaxial pipe C. The central portion of the central conductor Cc in the extending direction is The electromagnetic noise suppression sheet 1 (width 100 mm × length 60 mm), which is an electromagnetic noise countermeasure member according to the present invention, is covered.

  In the state shown in FIG. 5, the network analyzer N receives the input signal from the network analyzer N to the other end V of the coaxial tube, and measures the output signal output from the one end W of the coaxial tube C with the network analyzer N. .

  In the measurement method of the transmission loss effect, when an input signal is input to the coaxial tube C, the reflected power (reflection amount) of the electromagnetic noise suppression sheet 1 is based on changes in the electric field and magnetic field generated in the space of the coaxial tube C. And transmission power (transmission amount) change. The network analyzer N measures the transmission loss effect (power loss) P (loss) / P (in) of the electromagnetic noise suppression sheet 1 based on the change between the reflected power and the transmitted power. The larger the transmission loss effect P (loss) / P (in), the higher the effect of absorbing the input signal.

The transmission loss effect P (loss) / P (in) is calculated from the following equation (3).
P (loss) / P (in ) = 1-P 11 / P (in) -P 21 / P (in) ... (3)
In the equation, P (in) represents the input power in the measurement method of the transmission loss effect, P ₁₁ represents the reflected power of the electromagnetic noise suppression sheet 1 in the measurement method, and P ₂₁ represents the measurement method. The transmission power of the electromagnetic noise suppression sheet 1 is shown. The measurement method also measures the transmission loss effect of the electromagnetic noise suppression sheet 1 when P (in) is 1.

  FIG. 6 is a graph showing the results of measuring the transmission loss effect on the frequency of the input signal in the electromagnetic noise suppression sheet 1 having the magnetic layer 2 or the conductive layer 4 as the contact surface. The solid line is the result of measuring the magnetic field suppression effect using the electromagnetic noise suppression sheet 1 with the magnetic layer 2 as the contact surface. A dashed-dotted line is the result of measuring the magnetic field suppression effect using the electromagnetic noise suppression sheet 1 with the conductive layer 4 as the contact surface.

  As shown in FIG. 6, it has been found that the transmission loss effect P (loss) / P (in) is different depending on which of the magnetic layer 2 and the conductive layer 4 is used as the contact surface. More specifically, the electromagnetic noise suppression sheet 1 with the conductive layer 4 as the contact surface has a higher frequency band of 1 GHz to 4 GHz than the electromagnetic noise suppression sheet 1 with the magnetic layer 2 as the contact surface. It was confirmed that the transmission loss effect against electromagnetic noise was large. As a result, the electromagnetic noise suppression sheet 1 with the conductive layer 4 as the contact surface can obtain a higher transmission loss effect than the electromagnetic noise suppression sheet 1 with the magnetic layer 2 as the contact surface. found.

  As described above, the present inventors presume that the positional relationship between the magnetic layer 2 and the conductive layer 4 in the stacking direction is deeply related to enhance the desired effect on electromagnetic noise. And it was found that adjusting the positional relationship of the conductive layer 4 is extremely useful. And like the electromagnetic noise suppression sheet | seat 1 of this embodiment, the adhesion layer 3 interposes between the conductive layer 4 and the magnetic layer 2 in the lamination direction, and the adhesion layer 3 is the adhesion layer 3 in planar view. If the outer periphery is formed outside the outer periphery of the magnetic layer 2 and the conductive layer 4, the magnetic layer 2 side or the conductive layer 4 side is installed (adhered) with either the magnetic layer 2 side or the conductive layer 4 side as a contact surface during installation. You can choose to do it. Therefore, in the electromagnetic noise suppression sheet 1 of this embodiment, depending on the object on which the electromagnetic noise suppression sheet 1 is installed, it is selected which of the magnetic layer 2 and the conductive layer 4 is disposed in the lower layer. Thus, the effects (magnetic field suppression effect and transmission loss effect) of the electromagnetic noise suppression sheet 1 required by the object can be switched and acquired, and a flexible response is possible at the time of installation. Thereby, it becomes possible by using the electromagnetic noise suppression sheet | seat 1 of this embodiment to fully exhibit a desired effect.

  Moreover, in the electromagnetic noise suppression sheet | seat 1 of this embodiment, since the adhesion layer 3 is a single layer, it is thin compared with the conventional structure which has the adhesion layer 3 in the upper and lower layers of the electromagnetic noise suppression sheet | seat 1 in a lamination direction, and cost. Cost reduction can be achieved.

(Second Embodiment)
FIG. 7 is a schematic perspective view schematically showing the electromagnetic noise suppression sheet 15 of the second embodiment. The electromagnetic noise suppression sheet 15 in the present embodiment changes the planar shape of the adhesive layer 5 to a substantially rectangular shape, and its long side is longer than the magnetic layer 2 and the conductive layer 4, and its short side is the magnetic layer 2 and Except for being shorter than the conductive layer 4, it is configured in the same manner as the electromagnetic noise suppression sheet 1 of the first embodiment.

  As described above, the electromagnetic noise suppression sheet 15 of the present embodiment includes the adhesive layer 5 that adheres the magnetic layer 2 and the conductive layer 4 in the stacking direction, and the adhesive layer 5 is the adhesive layer 5 in a plan view. Since at least a part of the outer periphery of the magnetic layer 2 is formed outside the outer periphery of the magnetic layer 2 and the conductive layer 4, the magnetic layer 2 or the conductive layer 4 is placed on the electromagnetic noise generation source using either the magnetic layer 2 or the conductive layer 4 as a contact surface during installation ( Adhesion) can be selected. Therefore, also in the electromagnetic noise suppression sheet | seat 15 of this embodiment, there can exist an effect similar to the electromagnetic noise suppression sheet | seat 1 in the said 1st Embodiment.

  Moreover, in the electromagnetic noise suppression sheet | seat 15 of this embodiment, since the area of the adhesion layer 5 can be formed small compared with the electromagnetic noise suppression sheet | seat 1 in the said 1st Embodiment, with respect to a smaller target object However, it can be used and the cost can be further reduced.

(Third embodiment)
FIG. 8 is a schematic plan view schematically showing the electromagnetic noise suppression sheet 16 of the third embodiment, and FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. In the electromagnetic noise suppression sheet 16 according to the present embodiment, a hole 63 is formed at substantially the center of the adhesive layer 6 in the plane, and the magnetic layer 2 and the conductive layer 4 are laminated so as to close the hole 63 in plan view. Except for this, the electromagnetic noise suppression sheet 1 of the first embodiment is configured in the same manner. In addition, since the adhesion layer 6 is comprised from the base material 61 and the adhesive materials 60 and 62, and these correspond to the adhesion layer 3, the base material 31, and the adhesive materials 30 and 32 of 1st Embodiment, A duplicate description is omitted.

  As described above, the electromagnetic noise suppression sheet 16 of the present embodiment includes the adhesive layer 5 that adheres the magnetic layer 2 and the conductive layer 4 in the stacking direction, and the outer periphery of the adhesive layer 6 in a plan view is magnetic. Since it is formed outside the outer periphery of the layer 2 and the conductive layer 4, it can be selected whether to install (adhere) the magnetic layer 2 or the conductive layer 4 to the electromagnetic noise generation source with the contact surface at the time of installation. . Therefore, also in the electromagnetic noise suppression sheet | seat 16 of this embodiment, there can exist an effect similar to the electromagnetic noise suppression sheet | seat 1 in the said 1st Embodiment.

  Moreover, in the electromagnetic noise suppression sheet | seat 16 of this embodiment, since the hole 63 is formed in a part of adhesion layer 6, compared with the electromagnetic noise suppression sheet | seat 1 in the said 1st Embodiment, the adhesion layer 6 can be reduced, and the resistance component between the magnetic layer 2 and the conductive layer 4 can be suppressed. Furthermore, the cost can be further reduced.

(Fourth embodiment)
FIG. 10 is a schematic perspective view schematically showing the electromagnetic noise suppression sheet 17 of the third embodiment. In the electromagnetic noise suppression sheet 17 in the present embodiment, each of the magnetic layer 8 composed of a plurality of small pieces and the conductive layer 9 composed of a plurality of small pieces is adhered to the upper and lower surfaces of the adhesive layer 7, and Except that one side of the adhered small piece coincides with the outer periphery of the adhesive layer 7, it is configured in the same manner as the electromagnetic noise suppression sheet 1 of the first embodiment.

  As described above, the electromagnetic noise suppression sheet 17 of the present embodiment includes the adhesive layer 7 that adheres the magnetic layer 8 made of small pieces and the conductive layer 9 in the stacking direction, and at least the adhesive layer 7 in a plan view. Since a part of the magnetic layer 8 and the conductive layer 9 is formed outside the outer periphery, which of the magnetic layer 8 or the conductive layer 9 is to be installed (adhered) to the electromagnetic noise generation source with the contact surface as the contact surface during installation? You can choose. Therefore, also in the electromagnetic noise suppression sheet | seat 17 of this embodiment, there can exist an effect similar to the electromagnetic noise suppression sheet | seat 1 in the said 1st Embodiment.

  Moreover, in the electromagnetic noise suppression sheet | seat 17 of this embodiment, since the magnetic layer 8 and the conductive layer 9 consist of small pieces, it processes by a small piece unit at the time of installation compared with the electromagnetic noise suppression sheet | seat 1 in the said 1st Embodiment. Therefore, the workability of the electromagnetic noise suppression sheet is improved. Further, the cost can be further reduced.

  As described above, the electromagnetic noise suppression sheet of the present invention can select the contact surface with the electromagnetic noise generation source, and has the so-called effects (magnetic field suppression effect and transmission loss effect) that can be maximized for the required performance. Since it can be switched flexibly, it can be used widely and effectively in various electronic / electrical devices and various equipment, facilities, systems, etc. equipped with them, especially in high-speed differential transmission lines, signal lines and video signal lines. It can be used widely and effectively as a noise countermeasure.

  DESCRIPTION OF SYMBOLS 1,15,16,17 ... Electromagnetic noise suppression sheet | seat (electromagnetic noise countermeasure member), 2,8 ... Magnetic layer, 20 ... Binder, 21 ... Magnetic material, 3, 5, 6, 7 ... Adhesive layer, 30, 32, 60, 62 ... adhesive material 31, 61 ... base material, 4, 9 ... conductive layer, 40 ... binder, 41 ... conductor material, 63 ... hole, B ... base sheet, N ... network analyzer, MFP ... magnetic field probe, MSL: microstrip line, Ls, Li: input signal line, Lm: measurement signal line, T: one end of the microstrip line, S: other end of the microstrip line, C: coaxial tube, Cc: central conductor, V ... One end of the coaxial tube, W: the other end of the coaxial tube, Lo: an output signal line.

Claims (4)

A magnetic layer, an adhesive layer, and a conductive layer are laminated in this order,
At least a part of the adhesive layer is formed outside the outer periphery of the magnetic layer and the conductive layer,
Electromagnetic noise countermeasure material.   The electromagnetic noise countermeasure member according to claim 1, wherein the adhesive layer has a hole at substantially the center of the plane.   The electromagnetic noise countermeasure member according to claim 1, wherein each of the magnetic layer and the conductive layer includes a plurality of small pieces. An electromagnetic noise countermeasure member in which a magnetic layer, an adhesive layer, and a conductive layer are laminated in this order, and at least a part of the adhesive layer is formed outside the outer periphery of the magnetic layer and the conductive layer, Including the step of installing on the source of electromagnetic noise,
Electromagnetic noise countermeasure method.

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