JP2002141693A - Electromagnetic wave shielding body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable electromagnetic wave shielding body wherein, having flexibility and deformability (follows up bending into complex shape), applicable as, mainly, an EMC countermeasure material, the stability of material in weather-resistance is significantly improved as the electromagnetic wave shielding ability is kept high even at high-temperature and high-humidity, while the jointing characteristics (adhesion) to an elastomer material is further enhanced. SOLUTION: The electromagnetic wave shielding body comprises a substrate 2 comprising a conductive elastomer material, and an electromagnetic wave shielding film 1 formed on the substrate. The electromagnetic wave shielding film 1 is formed from an Ag alloy material in which Ag is a main component, with Au contained, and at least one kind of element selected out of Cu, Al, Ti, Pd, Ni, V, Ta, W, Mo, Cr, Ru and Mg is added as a third element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shield. In particular, portable information terminal devices such as notebook personal computers and mobile phones, display devices such as electronic devices, and liquid crystal displays (L
Electromagnetic waves used to shield electromagnetic waves, infrared rays and near-infrared rays emitted from display screens such as CDs and plasma display panels (PDPs) and to prevent, for example, radio wave harm caused by external electromagnetic waves entering electronic devices and the like. The present invention relates to an electromagnetic wave shield excellent in flexibility and flexibility that can be mounted inside the above-described various types of electromagnetic wave shields or bendable along the outer shape thereof.

[0002]

2. Description of the Related Art In the information society in recent years, as seen in the development of mobile communications such as satellite broadcasting systems and portable information terminal devices, the electromagnetic wave environment has become increasingly diversified and complicated. The evils along with the benefits they bring are becoming apparent. For example, when an external electromagnetic wave from the outside (outside) enters an electronic device or the like and leads to a bad noise,
In addition, there is a concern that electromagnetic waves leaking from portable information terminal devices such as notebook personal computers and mobile phones adversely affect the human body and adversely affect social life.

[0003] EMC (Electro Magnetic Compatibilit)
y), ie, electromagnetic compatibility (sometimes referred to as electromagnetic compatibility) is an element that solves engineering problems caused by electromagnetic waves.

Heretofore, metals have mostly occupied EMC materials for shielding external electromagnetic waves and leakage electromagnetic waves from personal computers and the like (hereinafter, referred to as "the former").
In addition, attempts to obtain conductivity by blending metal powder or carbon black with an elastomer material have been conventionally made (hereinafter, referred to as "the latter").

[0005]

However, the former EMC material is diversifying in products and elements that require EMC technology in recent years, and cannot respond to various functions that are not required only by metal. It is starting to be possible. For example, for the problem of bending followability to complex shapes and filling of unsteady space, weight reduction, corrosion resistance against rust, etc.
Various problems have occurred, such as its application often becoming difficult.

On the other hand, the latter elastomer filled with metal powder has many disadvantages such as a change with time mainly due to metal oxidation and a loss of mechanical properties such as elasticity and strength of the elastomer itself. It is hardly a popular material.

[0007] In addition, elastomers filled with carbon black have been diversified into conductive rollers, rubber contacts, and the like. However, since the obtained conductivity is limited, they are hardly used as EMC materials. .

As described above, the conventional electromagnetic wave shield has problems in followability to bending into a complicated shape, corrosion resistance, weather resistance, abrasion resistance, and the like. ) Was not performed.

The present invention has been made in view of the above circumstances, and has as its object to provide flexibility and shape flexibility (bending followability to a complicated shape) and to be mainly used as an EMC countermeasure material. It has a wide range of applications, and the material stability of weather resistance, such as continuous high electromagnetic wave shielding ability even in high-temperature and high-humidity environments, is remarkably improved. It is an object of the present invention to provide an electromagnetic wave shield capable of obtaining higher reliability, for example, by further enhancing (adhesion) more effectively.

[0010]

In order to solve the above problems, an electromagnetic wave shield according to the present invention comprises a substrate made of a conductive elastomer material and an electromagnetic wave shielding film formed on the substrate. The electromagnetic wave shielding film contains Ag as a main component, contains Au, and further has Cu,
Al, Ti, Pd, Ni, V, Ta, W, Mo, Cr,
It is characterized by being formed from an Ag alloy material obtained by adding at least one element selected from the group consisting of Ru and Mg.

According to the above-mentioned electromagnetic wave shield, the electromagnetic wave shield film made of the Ag alloy material is formed on the surface of the substrate made of the elastomer material, so that a shield having excellent flexibility can be obtained. This electromagnetic wave shield is flexible,
It has shape flexibility (bending followability to complex shapes)
It is widely applied mainly as an EMC countermeasure material, and can continuously maintain high electromagnetic wave shielding ability even in a high-temperature and high-humidity environment, and can remarkably improve the material stability of weather resistance.

The thickness of the electromagnetic wave shielding film is, for example, 10 to 500 in consideration of the ability to follow a complicated shape.
About nm is preferable. Further, as the elastomer material, natural rubber, chloroprene rubber, EPDM (rubber-like terpolymer of ethylene / propylene and diene) or the like can be used.

In the electromagnetic wave shield according to the present invention, the amount of Au added to the Ag alloy material is 0.1%.
It is preferable that the content is in the range of not less than wt% and not more than 3.0 wt%, and the addition amount of the third element is in the range of not less than 0.1 wt% and not more than 3.0 wt%.

Further, in the electromagnetic wave shielding body according to the present invention, the electromagnetic wave shielding film may be composed of one film or a plurality of films. Thereby, it is temperature and chemically stable and can be applied to various uses.

In the electromagnetic wave shielding body according to the present invention, the electromagnetic wave shielding film may be formed by forming a film on a substrate by an evaporation method using an evaporation material made of an Ag alloy material. is there. The electromagnetic wave shielding film may be formed by forming a film on a substrate by a sputtering method using a sputtering target material made of an Ag alloy material.

The electromagnetic wave shield according to the present invention may further include a protective film having excellent corrosion resistance and weather resistance formed on the electromagnetic wave shield film. In addition, it is possible to further include a protective film having excellent wear resistance formed on the electromagnetic wave shielding film.

Further, in the electromagnetic wave shielding body according to the present invention, the electromagnetic wave shielding body is disposed between the substrate and the electromagnetic wave shielding film.
It is also possible to further include a base film for promoting adhesion. Thereby, the bonding property (adhesion) with the elastomer material substrate can be more effectively enhanced, and higher reliability can be obtained.

Further, in the electromagnetic wave shield according to the present invention, the base film is made of ITO (composite oxide of In oxide and Sn oxide), IrO ₂ , ZnO ₂ , SiO ₂ , TiO ₂ , Ta
It is preferably formed using one or more materials selected from the group consisting of ₂ O ₅ and ZrO ₂ , or a material containing at least one of the one or more materials as a main component. Further, the base film is made of Si, Ta, Ti, Mo,
It is preferable to use a material formed of one or more elements selected from the group consisting of Cr and Al, or a material containing at least one of the one or more elements as a main component.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, self-diffusion energy with respect to heat possessed by Ag is reduced to suppress the phenomenon of clouding due to surface diffusion which is apt to occur when heated to at least about 100 ° C. It is important to.
That is, Ag is known to be the material having the best electromagnetic wave shielding ability. However, for example, a problem that self-diffusion energy for heat is active is likely to occur.
Therefore, when heat of about 100 ° C. is applied even temporarily, a diffusion phenomenon occurs on the surface, the Ag itself loses its luster and becomes cloudy, in other words,
This is because the characteristics of Ag itself, which is excellent in electromagnetic wave shielding ability, are easily reduced. Ag has a very good thermal conductivity and has a characteristic that it easily absorbs and saturates heat in atomic units.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an electromagnetic wave shield according to a first embodiment of the present invention. The electromagnetic wave shield includes a substrate 2 made of at least a conductive elastomer material. On the substrate 2, a base film 3 for promoting adhesion is arranged. The electromagnetic wave shielding film 1 is formed on the adhesion promoting base film 3.

The electromagnetic wave shielding film 1 is mainly composed of Ag,
u in an amount of 0.1 to 3.0% by weight (wt%), and Cu, Al, Ti, Pd, Ni, V, Ta,
It is formed from an Ag alloy material obtained by adding 0.1 to 3.0 wt% of at least one element selected from the group consisting of W, Mo, Cr, Ru, and Mg, and is formed by a sputtering method or a vapor deposition method. It is preferable to form a film.
The electromagnetic wave shielding film 1 may be composed of a plurality of films.

As an elastomer material for forming the substrate 2,
Natural rubber, chloroprene rubber, EPDM (rubber-like terpolymer of ethylene / propylene and diene) and the like can be mentioned.

The material of the adhesion promoting base film 3 is materially stable with respect to the substrate 2 made of oxygen or various materials, and the adhesion between the substrate and at least the electromagnetic wave shielding film 1 made of the above Ag alloy material. Is considered, Si, Ta, T
i, Mo, Cr, Al, ITO (composite oxide of In oxide and Sn oxide), IrO ₂ , ZnO ₂ , SiO ₂ , TiO ₂ ,
It is preferably formed using one or more materials selected from the group consisting of Ta ₂ O ₅ , ZrO ₂ , or the like, or a material containing at least one or more of these materials as a main component.

It has also been confirmed that the above-mentioned Ag alloy material has high chemical stability with respect to various elastomer materials such as natural rubber, chloroprene rubber, and EPDM, and is not limited to the material of the substrate made of the elastomer material. ing.

The base film 3 for promoting adhesion of the substrate 2 made of various elastomer materials is made of Si, Ta, Ti,
Mo, Cr, Al, ITO, ZnO ₂ , SiO ₂ , TiO
_{2, Ta 2 O 5, ZrO} 2 is desirable. The reason is that
Substrate 2 made of natural rubber or chloroprene rubber or EPDM generates a very large amount of gas in the case of a specific purity or material, the metal reacts strongly with the generated gas, and reacts with the bonding interface to be in close contact with the Ag alloy material. This is because it is difficult to say that it is appropriate because a floating body film (for example, an oxide film or the like) is likely to be formed.

When the above-mentioned material is formed on the substrate 2 as the adhesion promoting base film, a film forming method such as an evaporation method or a sputtering method can be considered. For example, when using a substrate made of natural rubber or chloroprene rubber or EPDM,
At the time of evacuation performed after putting the substrate into the deposition chamber,
In order to generate gas from the substrate, the degree of vacuum does not increase, and furthermore, the interface between the substrate and the adhesion-promoting base film tends to be unstable. Therefore, at least when the Ag alloy of the present invention is formed on a resin substrate, It is considered that it is desirable to form a film by vapor deposition.

According to the first embodiment, Ag is the main component, Au is contained, and Cu, A is used as the third element.
1, Ti, Pd, Ni, V, Ta, W, Mo, Cr, R
A thin film made of an Ag alloy material to which at least one element selected from the group consisting of u and Mg is added is used as the electromagnetic wave shielding film 1. Thereby, the heat resistance can be greatly improved, and the high shielding ability against the electromagnetic wave shielding effect of Ag itself can be maintained without lowering.

That is, the electromagnetic wave shielding film 1 has a high shielding ability against the electromagnetic wave shielding effect that cannot be obtained by the electromagnetic wave shielding film made of a material such as Au, Al, Cu and pure Ag which has been widely used in the past. Has been confirmed to be obtained. Also, the electromagnetic wave shield provided with the adhesion promoting base film 3 shown in FIG. 1 has a high electromagnetic wave shielding effect as in the case where the adhesion promotion base film 3 is not formed between the substrate 2 and the electromagnetic wave shielding film 1. Has been confirmed. in this case,
It has also been confirmed that the use of a conductive oxide such as ITO and ZnO ₂ as the adhesion-promoting base film 3 has a higher electromagnetic wave shielding effect than the use of SiO ₂ as the base film 3.

In the first embodiment, a specific adhesion promoting base film 3 for promoting adhesion between the substrate 2 and the electromagnetic wave shielding film 1 is formed as an intermediate base. For this reason, the bondability between the electromagnetic wave shielding film 1 and the substrate made of various materials with respect to the substrate 2 can be further effectively enhanced.

The material of the adhesion promoting underlayer 3 is as follows.
It is desirable that the resistance be lower. Low resistance
Preferably, the conductive layer is a non-magnetic conductive film. Specifically, Z
nO _TwoThe fact that ITO has a higher electromagnetic wave shielding effect than ITO
Has been confirmed. The reason for this is that electromagnetic waves
Ag alloy material of at least three elements for shielding
And a specific intermediate underlayer between the Ag alloy material film and the substrate.
When a film is provided and an electric field is applied to the multilayer film itself,
A conductive current flows inside the multilayer film, and this electric energy is
Is converted into heat energy,
Electromagnetic waves are mainly caused by the heat generating mechanism that performs the conversion.
This is because absorption causes conduction loss. Also, this guide
The electric loss depends on the amount of the conduction current that flows with less resistance.
Is higher, the lower the resistance of the electromagnetic wave shielding film, the lower
The advantage difference is remarkable.

However, for Ag, Al, and Cu, the movement of atoms of the material itself, that is, the heat generation mechanism that converts electric energy to heat energy by the electromigration phenomenon is attenuated with the passage of time. Although the damping effect has been reduced by providing at least a specific film thickness, it has been confirmed that in the above-described Ag alloy material, the film itself does not actively move between metal atoms, so that the damping effect is significantly reduced.

A dielectric such as SiO ₂ , TiO ₂ , Ta ₂ O ₅ , or ZrO ₂ , which is not insulated from conductive oxides represented by ITO and ZnO ₂ , but is insulative, is referred to as A.
When interposed as an adhesion promoting base film between the g alloy material and the substrate, in addition to the effect of the high conduction loss possessed by the Ag alloy material, the effect of absorbing electromagnetic wave energy at high frequency called dielectric loss is also performed. Therefore, it is not necessary to limit the metal oxide interposed as at least the adhesion promoting underlayer to a conductive material.

That is, in the electromagnetic wave shielding film 1 formed of the Ag alloy material described above, Si, Ta, Ti,
Metal film of Mo, Cr, Al, etc., ITO, ZnO
_2. High electromagnetic wave shielding effect even when an adhesion promoting base film 3 using a metal oxide such as SiO ₂ , TiO ₂ , Ta ₂ O ₅ , ZrO ₂ and a metal composite oxide is interposed. Has been confirmed.

The adhesion-promoting base film 3 is made of, for example, S
When a metal film such as i, Ta, Ti, Mo, Cr, or Al is used, the film can be formed by any of an evaporation method, a sputtering method, a CVD method, and an ion plating method. Therefore, it can be said that general utility is high.

Further, ITO, ZnO ₂ , SiO ₂ , TiO
₂ , Ta ₂ O ₅ , ZrO _{2 and} other metal oxide thin films,
A film can be easily formed by any of an evaporation method, a sputtering method, a CVD method, and an ion plating method. For example, for an AR (anti-reflection) coat formed on the surface side of a cathode ray tube monitor, a liquid crystal display device, or the like, a highly transparent adhesion-promoting base film 3 is formed on a substrate 2 made of various elastomer materials, 0.5 ~ thickness on the ground film
By forming an electromagnetic wave shielding film of 1.2 nm and forming an AR coat thereon, a remarkable shielding effect against electromagnetic waves from the display device itself is exhibited.

In the first embodiment, the material stability of Ag itself can be remarkably improved, and when it is used as a laminated structure, it can be laminated irrespective of the material of the substrate. Can be more effectively strengthened, and higher reliability can be obtained.

Further, the case of a single electromagnetic wave shielding film 1 and FIG.
It has been confirmed that both of the electromagnetic wave shields shown in Table 1 have excellent heat resistance and weather resistance. In addition, it has been confirmed that it is highly useful, for example, as an electromagnetic wave shield for recent EMC countermeasure materials, which has a wide range of applications.

Further, the electromagnetic wave shielding body in which the electromagnetic wave shielding film 1 made of the Ag alloy material described above is formed on the surface of the substrate 2 made of various elastomer materials is different from a conventional elastomer in which metal powder or carbon black is blended. And 1
It has been confirmed that the electric field intensity attenuation rate (dB) and the radio wave absorption capacity (dB) in the low frequency range from 00 MHz to 10 GHz range are excellent, and the flexibility (cm) is also excellent.

An electromagnetic wave shielding film 1 made of the above-mentioned Ag alloy material is formed on the surface of a substrate 2 made of the above-mentioned various elastomer materials on a portable information terminal device or the like represented by a notebook personal computer or a portable telephone. When an electromagnetic wave shield is applied, it is necessary that the electromagnetic wave shield can be bent and provided along the outer shape, for example. Regarding this, it has been confirmed that the electromagnetic wave shield is excellent in bending followability (shape flexibility) to a complicated shape, since even if it is bent at 90 °, no crack or the like is generated on the surface thereof. ing.

In the case where the electromagnetic wave shielding film 1 made of an Ag alloy material is formed on the surface of the substrate 1 made of an elastomer material, for example, in the sputtering method, the sputtering rate, which is the speed reference for forming the film, is higher than in the conventional method. Further, although the Ag alloy material has a melting point of about 960 ° C., it does not belong to a high class among the metal elements, so that the versatility of deposition temperature conditions and the like are not inferior to the conventional one. Therefore, since the film formation method can be arbitrarily selected depending on the material of the substrate, it is known that there is a remarkable superiority in the production by the film formation method as compared with the related art. Note that as a film formation method, a sputtering method using an RF or DC power supply, a vacuum evaporation method, and a CVD method are preferable.

In addition, since the vapor deposition method is inferior to the sputtering method in terms of denseness of the film, generally, when a thin film is formed by the vapor deposition method, a thicker film is formed than when a thin film is formed by the sputtering method. It is required. However, A
Since the electromagnetic wave shielding effect does not decrease in the electromagnetic wave shielding film 1 made of a g alloy material, the same electromagnetic wave shielding effect can be obtained with the same film thickness by the vapor deposition method or the sputtering method.

FIG. 2 is a sectional view showing an electromagnetic wave shield according to a second embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and only different parts will be described.

When an electromagnetic wave shield is applied to a portable information terminal device or the like, it is conceivable that a part of a human body or some object directly contacts the portable information terminal device. In this case, when the Ag alloy material film forming the electromagnetic wave shield is exposed, at least the surface portion is shaved by contact with a human body or an object, or a conductive trace effect is reduced by leaving a scar, or It is conceivable that the shielding ability for a specific electromagnetic wave shielding effect is reduced. For this reason, the protective film 4 having excellent corrosion resistance and weather resistance and excellent wear resistance is formed on the electromagnetic wave shielding film 1 for the purpose of suppressing the occurrence of shaving of the surface portion and the occurrence of damage due to surface contact. Thereby,
It is possible to prevent a contact flaw caused by any contact with the exposed electromagnetic wave shielding film 1.

Further, even when the protective film 4 is formed, the lowering of the electromagnetic wave shielding ability is suppressed, the adhesion promoting base film 3 is formed between the substrate 2 and the electromagnetic wave shielding film 1, and the protective film 4 is formed thereon. It has been confirmed that the electromagnetic wave shielding performance of the laminated structure does not decrease.

In the second embodiment, the same effect as in the first embodiment can be obtained.

Since Ag has a very good thermal conductivity and has a characteristic of easily absorbing and saturating heat in atomic units, Ag is used in order to slow down the thermal conductivity and suppress active movement between atoms. Pd is an atom that forms a solid solution with respect to
Was arbitrarily shaken in a composition range of 0.1 to 4.0 wt% to conduct an experiment.

First, Ag and Pd sputtering targets are mounted on the sputtering apparatus, respectively, and the discharge amount of Ag and Pd is controlled with a specific RF power, and Ar gas is arbitrarily set within a range of 0.1 to 3.0 Pa. Set and sputter two materials simultaneously. That is, the Ag alloy material film was formed by varying the addition amounts of several types of Pd by the simultaneous sputtering method.

At this time, the test sample was a quartz substrate, the substrate temperature during the sputtering process was room temperature (about 25 ° C.), and only Ar gas was used as the sputtering gas.
Evacuation was performed to a high vacuum of 3 × 10 ⁻⁶ Pa as the ultimate vacuum degree, and the film thickness was reduced to 20 n in an argon gas atmosphere.
m.

The reason why the film is formed in a high vacuum atmosphere is that the intrinsic physical properties of the material can be confirmed by forming a dense film while suppressing that the impurity gas and the like depend on the grain boundaries of the alloy film. To try.

An Ag alloy material thin film containing Ag formed as a main component and Pd added with several kinds of material compositions is placed on a hot plate in the air and left for about 2 hours to form a white turbidity. A heating test was conducted to observe the presence / absence and the temperature at which clouding started. At this time, the heating method of the hot plate is a resistance heating method, and the heating temperature is 2
The heating rate was set to 50 ° C. and the heating rate was set to 20 ° C./min. Table 1 shows the test results.

[0051]

[Table 1]

In general, it is well known that the addition of Pd improves the lack of weather resistance in a high-temperature and high-humidity environment possessed by Ag. As for the diffusivity, no remarkable difference could be confirmed as shown in Table 1, and no remarkable superiority could be confirmed with respect to the reduction of white turbidity due to the addition of Pd as compared with Ag. In addition, since it was confirmed that the electromagnetic wave shielding ability was reduced by about 2 to 3% after heating as compared to before heating, the effect of preventing surface diffusion by adding Pd could not be confirmed.

Next, a heating test was performed on the above-described Ag alloy material, which will be described. As a method for forming a thin film, one selected from any of sputtering target materials such as Ag, Au, and Cu is mounted on an RF magnetron sputtering apparatus, and the three metal elements are simultaneously sputtered. And a thin film made of a three-element Ag alloy material.

At this time, a quartz substrate was used as a test substrate, the substrate temperature during the sputtering process was room temperature (about 25 ° C.), and only Ar gas was used as a sputtering gas.
After evacuation was performed to a high vacuum of 3 × 10 ⁻⁶ Pa as the ultimate degree of vacuum, the film thickness was reduced to 2 in an argon gas atmosphere.
It was formed at 0 nm.

The test sample in this method contains A as the main component.
g of a three-element Ag alloy material thin film obtained by adding 0.1 to 3.0 wt% of Au to Cu and adding 0.1 to 3.0 wt% of one of Cu and the like. It is formed directly on the surface with a film thickness of 20 nm, and the heating temperature is set to 25 as described above.
A heating test was performed in which the sample was placed on a hot plate maintained at 0 ° C. and allowed to stand for about 2 hours to observe the presence or absence of cloudiness and the temperature at which clouding started. Tables 2 to 5 show the test results.

[0056]

[Table 2]

[0057]

[Table 3]

[0058]

[Table 4]

[0059]

[Table 5]

In the Ag alloy material of the present invention, as can be seen from Tables 2 to 5, the clouding phenomenon and the decrease in the electromagnetic wave shielding ability are as follows.
Not observed in all material composition ranges.

Then, the quartz substrate on which the Ag alloy material films formed in various material composition ranges subjected to the heating test at 250 ° C. are further left on a hot plate heated to 400 ° C. for 2 hours. In any case, no clouding or reduction in electromagnetic wave shielding ability was observed in any of the material composition ranges.

Next, a test for observing the change over time of the electromagnetic wave shielding characteristics made of the Ag alloy material described above was performed. In order to confirm the chemical stability of the Ag alloy material film, natural rubber or chloroprene rubber or E
Using a test sample in which an electromagnetic wave shielding film 1 having a thickness of 15 nm was formed on the surface of a substrate 2 made of various materials such as PDM by a ternary simultaneous sputtering method as in the past, at a temperature of 90 ° C. and a humidity of 90% It was left for 24 hours in a high-temperature and high-humidity environment to observe changes in its appearance and electromagnetic wave shielding characteristics over time. Tables 6 to 9 show the test results.

[0063]

[Table 6]

[0064]

[Table 7]

[0065]

[Table 8]

[0066]

[Table 9]

As is clear from Tables 6 to 9, no change with time was observed in the material even after standing for 24 hours.
The electromagnetic wave shielding ability of an Ag alloy material film formed on the surface of a substrate made of various materials such as natural rubber, chloroprene rubber, or EPDM was measured and observed by a KEC method (a device devised by Kansai Electronics Promotion Center). In a wide range from a low frequency range of 100 MHz to a 1 GHz range, no reduction in electromagnetic wave shielding ability was confirmed.

Separately, from the low frequency range of 100 MHz by the near-field measurement of the electromagnetic wave shield obtained in the present invention, the frequency of
Since the electric field intensity attenuation rate (dB) up to the GHz range is required to be 20 dB or more, the radio wave absorption capacity (dB) and the flexibility (cm) from the low frequency range of 100 MHz to the 1 GHz range were measured.

The flexibility was measured by holding the end of the test sample (electromagnetic wave shield obtained in the present invention) cut to an appropriate size (for example, a strip having a width of 10 nm). , The test sample was gradually taken out from the test sample, and the index was obtained by measuring the length of the test sample on the test table at the time when the hanging portion became just 90 °. Table 10 shows the measurement results.

The near field means an electric field at a distance of λ / 6 wavelength or less when the wavelength is λ in radio wave engineering. The electric field intensity attenuation rate is an index of the electromagnetic wave shielding ability, and the electromagnetic wave shielding ability of a material is measured by an automatic measuring device that makes the measurement principle the same.

COMPARATIVE EXAMPLE As a comparative example, 100 parts of a vinyl group-containing polydimerylsiloxane having an average degree of polymerization of about 6,000 containing 0.06% of a merylvinylsiloxane unit, which is a dimethylvinylsilyl group, in both terminals was added to conductive carbon Furness Black “# 3030B” (Mitsubishi Chemical Corporation) 4
After 0 parts and 10 parts of silicon earth were charged into a kneader and kneaded, 2,5-dimethyl-2,5-di-methyl was further added as a crosslinking agent.
1.5 parts of t-butyl peroxyhexane was added to obtain a uniform silicone bomb compound. Then, a test sample was prepared by forming a rubber plate having a thickness of 1 nm and a side of 100 mm on each side by press molding the compound at 170 ° C. for 10 minutes and vulcanizing at 200 ° C. for 4 hours. In addition, as a sample for measuring the electromagnetic wave absorption capacity, a thickness of 7.
A rubber plate having a thickness of 5 nm and a side of 50 mm was prepared by the same method and procedure as described above.

[0072]

[Table 10]

As is clear from Table 10, the above-described Ag
The electromagnetic wave shielding body of the present invention in which the electromagnetic wave shielding film 1 made of an alloy material is formed on the surface of the substrate 2 made of various materials has a low frequency of 100 MHz as compared with a conventional elastomer obtained by blending metal powder or carbon black. 10 GHz from frequency range
Electric field intensity attenuation rate (dB) in the z region, radio wave absorption capacity (d
B) was confirmed to be excellent, and also excellent in flexibility (cm). In addition, it was confirmed that it was excellent in bending followability.

The present invention is not limited to the above embodiment, but can be implemented with various modifications.

[0075]

As described above, according to the present invention, the following effects can be obtained. The electromagnetic shielding material obtained by forming an electromagnetic shielding film on a substrate using the Ag alloy material of the present invention has the same flexibility and shape flexibility (complex shape) as an elastomer obtained by blending a conventional metal powder or carbon black. And a very stable electromagnetic wave shielding effect as compared with the elastomer can be maintained. Therefore, it is possible to obtain a high-quality electromagnetic wave shield that avoids deterioration of the electromagnetic wave shielding ability due to conductive loss useful for maintaining the electromagnetic wave shielding effect for a long period of time.

The electromagnetic wave shielding film formed by using the Ag alloy material of the present invention can maintain high visible light transmittance and solar light transmittance over a wide range from a low frequency range to a high frequency range. A higher electromagnetic wave shielding effect can be obtained as compared with an elastomer containing a metal powder or carbon black.

In the case where the electromagnetic wave shielding film is formed on the substrate using the Ag alloy material of the present invention, any of the sputtering method, the vapor deposition method and the CVD method can be used.
It is possible to maintain a stable productivity and an electromagnetic wave shielding effect for a long period of time as compared with the related art.

In the case where an electromagnetic wave shielding body is manufactured using the electromagnetic wave shielding film made of the Ag alloy material of the present invention, the electromagnetic wave shielding effect is obtained by disposing the adhesion promoting base film between the substrate and the electromagnetic wave shielding film. , The adhesion of the electromagnetic wave shielding film to the substrate can be improved, and the coupling between the two can be enhanced.

In the electromagnetic wave shielding body of the present invention, a protective film made of a material having excellent corrosion resistance and weather resistance or a material having excellent wear resistance is formed on the surface of the electromagnetic wave shielding film.
The surface part is cut off by contact with the human body or object, the conductive loss effect is reduced by leaving a scar, and the shielding ability against the specific electromagnetic wave shielding effect caused by the surface shaving or the scar is reduced. Can be suppressed.

Therefore, according to the present invention, by forming an electromagnetic wave shielding film made of an Ag alloy material on the surface of a substrate made of an elastomer material, a shield having excellent flexibility can be obtained. This electromagnetic wave shield is flexible,
In addition to its shape flexibility (bending followability to complex shapes), it can maintain a high shielding ability against the electromagnetic wave shielding effect possessed by Ag itself, and also has a high electromagnetic wave even in a high-temperature, high-humidity environment. The shielding ability can be continuously maintained, and the material stability of weather resistance can be remarkably improved. In addition, the adhesion to the elastomer material substrate can be more effectively enhanced by the interposition of the adhesion promoting base film, whereby the reliability with the substrate can be further improved, and the EMC measures can be obtained. The application development can be widely expected as a material.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electromagnetic wave shield according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing an electromagnetic wave shield according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electromagnetic wave shielding film 2 ... Substrate 3 ... Adhesion promotion base film 4 ... Protective film

Claims (10)

[Claims] 1. A substrate made of a conductive elastomer material, and an electromagnetic wave shielding film formed on the substrate, wherein the electromagnetic wave shielding film contains Ag as a main component and contains Au,
Further, as a third element, Cu, Al, Ti, Pd, Ni,
An electromagnetic wave shield comprising an Ag alloy material to which at least one element selected from the group consisting of V, Ta, W, Mo, Cr, Ru, and Mg is added. 2. The method according to claim 1, wherein the addition amount of Au in the Ag alloy material is in a range of 0.1 wt% or more and 3.0 wt% or less,
The electromagnetic wave shield according to claim 1, wherein the amount of the third element added is in a range of 0.1 wt% or more and 3.0 wt% or less. 3. The electromagnetic wave shielding body according to claim 1, wherein the electromagnetic wave shielding film is formed of one film or a plurality of films. 4. The electromagnetic wave shielding film according to claim 1, wherein the electromagnetic wave shielding film is formed on the substrate by a vapor deposition method using a vapor deposition material made of an Ag alloy material. The electromagnetic wave shield according to the above. 5. The electromagnetic wave shielding film according to claim 1, wherein the electromagnetic wave shielding film is formed on the substrate by a sputtering method using a sputtering target material made of an Ag alloy material. Item 7. The electromagnetic wave shield according to Item 1. 6. The electromagnetic wave shield according to claim 1, further comprising a protective film having excellent corrosion resistance and weather resistance formed on the electromagnetic wave shield film. 7. The electromagnetic wave shield according to claim 1, further comprising a protective film having excellent wear resistance formed on the electromagnetic wave shield film. 8. The electromagnetic wave shielding device according to claim 1, further comprising a base film disposed between the substrate and the electromagnetic wave shielding film to promote adhesion. body. 9. The method according to claim 1, wherein the under film is made of ITO, IrO ₂ , Zn.
One or a plurality of materials selected from the group consisting of O ₂ , SiO ₂ , TiO ₂ , Ta ₂ O ₅ , and ZrO ₂ , or a material formed using at least one or more of the above materials as a main component The electromagnetic wave shield according to claim 8, wherein 10. The method according to claim 1, wherein the base film is made of Si, Ta, Ti, M
Claims characterized by being formed using a material consisting of one or more elements selected from the group consisting of o, Cr, and Al, or a material containing at least the one or more elements as a main component. Item 9. An electromagnetic wave shield according to item 8.