JP2002111274A - Granular material having electromagnetic wave absorption property and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a granular material having an electromagnetic wave absorption property and its manufacturing method which contains electromagnetic wave absorbers at an average and adequate distribution and can easily manufacture a quality-stabilized electromagnetic wave absorbing material. SOLUTION: A granular material 30 having an electromagnetic wave absorption property is composed of electromagnetic wave absorbing absorbers 24 uniformly dispersed around a block of core 36 and mixed in a matrix. The absorbers 24 are averagely dispersed around the core 36 in the granular material 30 to stabilize the electromagnetic wave absorption property, and hence a granular material 30 having a quality-stabilized electromagnetic wave absorption power can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for manufacturing a building for preventing disturbance due to unnecessary electromagnetic waves in a place where communication, detection, or measurement is performed using electromagnetic waves, in which an electromagnetic wave absorber is efficiently installed inside the member. The present invention relates to a well-arranged granular material having electromagnetic wave absorption characteristics and a method for producing the same.

[0002]

2. Description of the Related Art As part of an intelligent transportation system (ITS), which is a next-generation road transportation system, development of an automatic toll collection system (ETC) for toll roads and a driving support system (AHS) for vehicles running on roads. Is progressing.

[0003] This automatic toll collection system does not stop the traffic of a car traveling on a toll road such as an expressway, and the automatic toll payment device (IC card, radio wave tag, etc.) mounted on the car and the toll booth of the toll booth. This is a system for collecting tolls by wireless communication with an automatic toll collection device arranged at a gate. This automatic toll collection system is expected to be introduced not only from the viewpoint of simple payment of tolls, but also from the viewpoint of alleviating traffic congestion and reducing labor costs.

[0004] In the automatic toll collection system, a detection means such as a radar of an automatic toll collection device arranged at the toll gate detects that an automobile traveling on the road has approached the toll gate to a predetermined distance.

[0005] Then, the wireless communication device of the automatic toll collection device transmits a signal to the running car, and information (vehicle type, contract contents, Payment account, etc.) by wireless communication. Then, the vehicle-side automatic toll payment device transmits information necessary for determining the vehicle toll to the wireless communication device of the automatic toll collection device.

[0006] The automatic toll collection device that receives the information necessary for discriminating the toll of the car calculates the toll based on the mileage of the car on a toll road and executes the toll collection processing.

[0007] Further, in a vehicle driving support system, for example, a lane marker is installed at each predetermined position on a road along the driving lane on the road, and a radar of a driving support device mounted on the vehicle running on the road is provided. And the like detect the position of the lane marker to detect an appropriate driving route, and warn the driver of the possibility of departure from the driving lane or drive the vehicle to drive the vehicle along the appropriate driving route. Automatically intervene in the equipment to help drive safely. In addition, various communication is performed between the communication device of the lane marker arranged on the road and the vehicle, which is useful for determining a traveling route and provided for transportation.

[0008]

In the above-described automatic toll collection system and car driving support system in the intelligent transportation system, a moving car is used as a target and communicates using a relatively high frequency electromagnetic wave. ,
Detect or measure. For this reason, at the moment when a running automobile runs through a predetermined place, it is necessary to accurately execute an operation of communicating, detecting or measuring using electromagnetic waves of a relatively high frequency.

However, in the automatic toll collection system or the vehicle driving support system, unnecessary high-frequency electromagnetic waves emitted from these systems are radiated on a road or the like to generate unnecessary scattered electromagnetic waves. Then, the unnecessary scattered electromagnetic waves are received by the receiver of the automatic toll collection system or the driving support system of the vehicle, and there is a possibility that an error occurs in the operation of communication, detection or measurement.

[0010] Since such an automatic toll collection system or a vehicle driving support system is intended for vehicles traveling outdoors, the automatic toll collection system or the vehicle driving support system must be installed in an open field. Therefore, in this automatic toll collection system or a vehicle driving support system, unnecessary scattering electromagnetic waves are generated by surrounding the automatic toll collection system or the vehicle driving support system with an electromagnetic wave reflection plate, as in a commonly used means for preventing electromagnetic interference. No means can be taken to shield the

Therefore, by constructing buildings such as roads and tollgate buildings with an electromagnetic wave absorbing material having a function of absorbing electromagnetic waves by utilizing the internal loss of members, the electromagnetic waves emitted from these systems can be efficiently used. It has been proposed to be able to absorb well and prevent the generation of unnecessary scattered electromagnetic waves.

Therefore, it is conceivable to manufacture and use an electromagnetic wave absorbing material made of a material mixed with ferrite, which is a magnetic material. Although ferrite is a material having excellent absorption characteristics, it can cope with the frequency band of the electromagnetic wave to be absorbed. Is adjusted by the thickness of the ferrite member. For this reason, the electromagnetic wave absorbing material has a disadvantage that it is difficult to use as a building material, for example, the weight of the ferrite mixed therein increases and the weight of the electromagnetic wave absorbing material itself increases.

It is also conceivable to manufacture or construct an electromagnetic wave absorbing material by mixing a relatively light, short fibrous dielectric material or the like into a construction material. In this case, it is necessary that the electromagnetic wave absorbing material has a short fibrous dielectric material disposed therein in an average and appropriate distribution state.

For example, in the case of manufacturing such an electromagnetic wave absorbing material, if the short fibrous dielectric material is thoroughly mixed with the aggregate and the binder and is not evenly distributed to every corner, sufficient electromagnetic wave absorbing characteristics are required. Therefore, it is not possible to obtain an electromagnetic wave absorbing material having a predetermined quality and a stable quality.

In view of the above facts, the present invention has an electromagnetic wave absorber for arranging electromagnetic wave absorbers in the inside thereof in an average and appropriate distribution so as to easily manufacture an electromagnetic wave absorbing material of stable quality. It is an object of the present invention to newly provide a granular material having characteristics and a manufacturing method thereof.

[0016]

According to the present invention, there is provided a granular material having an electromagnetic wave absorbing property according to claim 1 of the present invention comprising: a mass of nuclei; a substrate adhered and solidified around the core; An electromagnetic wave absorber that absorbs the electromagnetic waves evenly dispersed and mixed,
It is characterized by having.

With the above-described structure, the electromagnetic wave absorbers are dispersed and arranged around the nucleus inside the granular material, so that the electromagnetic wave absorption characteristics are stabilized and the electromagnetic wave absorption characteristics with stable quality are obtained. A granular material can be obtained. In addition, the granular material having the electromagnetic wave absorption characteristics has a function of favorably absorbing electromagnetic waves. Furthermore, by forming a layer of a mixture of the base material and the electromagnetic wave absorber with a substantially uniform thickness around the nucleus, the outer shape and size of the granular material can be made uniform.

According to a second aspect of the present invention, there is provided a method for producing a granular material having an electromagnetic wave absorbing characteristic, wherein a material obtained by uniformly dispersing and mixing electromagnetic wave absorbers for absorbing electromagnetic waves in a base material is used to form a mass of cores. The method is characterized by comprising a step of adhering to the periphery and a step of integrally solidifying the core with a mixture of the base material and the electromagnetic wave absorber attached to the periphery.

According to the above-described manufacturing method, a granular material in which the electromagnetic wave absorber is dispersed in the substrate solidified around the core can be easily manufactured. Further, the granular material can be manufactured with a uniform outer shape and size. Therefore, it is possible to mass-produce a granular material having an electromagnetic wave absorbing characteristic with stable quality.

According to a third aspect of the present invention, there is provided a method for producing a granular material having an electromagnetic wave absorbing characteristic, wherein a material obtained by uniformly dispersing and mixing an electromagnetic wave absorber for absorbing electromagnetic waves and a foam material in a base material. , A step of adhering around the core of a lump, and baking in the state of adhering a mixture of the base material and the electromagnetic wave absorber around the core to form a foam at the portion including the base material And solidifying integrally with each other.

According to the above-described manufacturing method, a granular material in which the electromagnetic wave absorber is dispersed evenly in the substrate solidified in a state of being foamed around the core can be easily manufactured. Further, the granular material can be manufactured with a uniform outer shape and size. An electromagnetic wave absorber disposed on a side wall portion between voids in a granular material having an electromagnetic wave absorbing property,
Since it is arranged on the average so as to correspond to the surface partitioning the gap, electromagnetic waves can be favorably absorbed.

The granular material having electromagnetic wave absorbing properties according to claim 4 of the present invention comprises a mass of a core and an outer portion of the core,
An electromagnetic wave absorber arranged in a layer containing a nucleus, and a base material outside the nucleus and arranged in a layer containing the nucleus, having a layer of the electromagnetic wave absorber and a layer of the base material Have a laminated structure.

With the above arrangement, the electromagnetic wave absorber is arranged in a layer around the nucleus and then dispersed in the vicinity thereof, so that the electromagnetic wave absorber is dispersed evenly over the entire outside of the nucleus. be able to. Thereby, the property of absorbing the electromagnetic wave of the granular material can be made more uniform at each outer peripheral portion of the granular material, and the electromagnetic wave absorbing characteristic of the granular material can be stabilized to further improve the reliability.

According to a fifth aspect of the present invention, there is provided a method for producing a granular material having an electromagnetic wave absorbing property, wherein a step of attaching an electromagnetic wave absorber for absorbing electromagnetic waves to the outside of a core, and a step of attaching a base to the outside of the core. Attaching a material or a material containing the same,
A step of attaching the electromagnetic wave absorber and the base material or a material containing the same to the outside of the nucleus and laminating them together to form a solidified body.

According to the above-described manufacturing method, since the electromagnetic wave absorber is arranged in a layer around the core, the granular material in which the electromagnetic wave absorber is dispersed evenly over the entire outside of the core can be easily obtained. Can be manufactured. At the same time, since the electromagnetic wave absorbers are dispersed and arranged around the nucleus inside the granular material on average, the granular material having electromagnetic wave absorption characteristics has a function of absorbing electromagnetic waves well, and the electromagnetic wave absorption It is possible to obtain a granular material having stable electromagnetic wave absorption characteristics with stable characteristics. In addition, around the nucleus,
Since each layer of the base material and the electromagnetic wave absorber is formed with a substantially uniform thickness, the outer shape and size of the granular material can be made uniform.

According to a sixth aspect of the present invention, there is provided a method for producing a granular material having an electromagnetic wave absorbing characteristic, wherein a step of attaching an electromagnetic wave absorber for absorbing electromagnetic waves to the outside of a core of a block, and a step of attaching a base material outside the core. A step of attaching a material and a foaming material or a material containing them, and baking the electromagnetic wave absorber and a substrate and a foaming material or a material containing them on the outside of the nucleus and firing in a laminated state. And solidifying integrally in a state of foaming in a portion containing

According to the manufacturing method as described above, the electromagnetic wave absorber is disposed on the side wall between the voids in the substrate solidified in a state of being foamed around the core, and the surface that partitions the void is formed. Are arranged in an averagely dispersed manner corresponding to the above, so that electromagnetic waves can be favorably absorbed. Therefore, it is possible to mass-produce a granular material having an electromagnetic wave absorbing characteristic with stable quality.

According to a seventh aspect of the present invention, in the granular material having the electromagnetic wave absorbing characteristics according to the first or fourth aspect, the electromagnetic wave absorber is a carbon fiber.

With the above configuration, the design can be changed so as to obtain the required electromagnetic wave absorption characteristics only by changing and adjusting the length of the carbon fiber in accordance with the wavelength of the electromagnetic wave to be absorbed. Even when the wavelength of the electromagnetic wave to be absorbed is different, it can be handled without changing the weight of the granular material using the carbon fiber.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a granular material having an electromagnetic wave absorbing characteristic of the present invention and a method of manufacturing the same will be described with reference to FIGS. FIG. 1 is a perspective view showing a schematic configuration of an automatic toll collection point on a toll road as a structure constructed by using a granular material having electromagnetic wave absorption characteristics according to an embodiment of the present invention.

In this automatic toll collection station, each of the automatic toll collection devices 12 is arranged in a toll gate 10 installed at a predetermined place on a toll road, corresponding to each traveling lane of the toll road.

The automatic toll collection device 12 includes a vehicle detection radar and a radio communication device. The automatic toll collection device 12 emits a millimeter wave of a radar from a radar for vehicle detection to a predetermined range in front of the toll gate 10, and transmits a vehicle 14 to a predetermined position in front of the toll gate 10.
Is configured to detect that the user has arrived.

In the automatic toll collection device 12, the vehicle 1 is located at a predetermined position on a road lane by a vehicle detection radar.
4 is detected, the communication signal MW is emitted from the wireless communication device of the automatic toll collection device 12, and the traveling vehicle 1
4 is transmitted.

The vehicle 14 is equipped with an automatic toll payment device (not shown), which receives a communication signal MW from the wireless communication device of the automatic toll collection device 12. Then, the automatic toll payment device transmits information (vehicle type, weight, model, registration number, and the like) necessary for collecting the toll of the vehicle 14 by wireless communication.

The automatic toll collection device of the automatic toll collection device 12 which has received the information necessary for determining the toll of the vehicle 14 calculates the toll based on the mileage of the automobile on the toll road, and collects the toll. Execute the process.

In the above-described automatic toll collection station, at least a predetermined range in which a communication signal MW, which is a radio wave in a frequency band of 5.80 GHz, emitted from the wireless communication device of the automatic toll collection device 12 with a directivity is irradiated. A portion of a road or a building extending over a predetermined range irradiated with a millimeter wave emitted from a vehicle detection radar of the automatic toll collection device 12, absorbs low-intensity electromagnetic waves for communication, detection, or measurement. Construction is made of an electromagnetic wave absorbing material manufactured using a granular material having electromagnetic wave absorbing characteristics.

Thus, it is possible to prevent the operation of wireless communication or vehicle detection from being hindered by electromagnetic interference caused by radio waves that are unnecessarily reflected on a road surface or a building, thereby preventing troubles in operations such as toll collection.

For this reason, a pavement-structured road having a function of absorbing low-intensity electromagnetic waves for communication, detection or measurement is constructed as shown in FIG. 2 or FIG.

In the road shown in FIG. 2, a protective layer 16 is formed at the outermost surface of the road, a surface layer 18 is disposed under the protective layer 16, an electromagnetic wave reflection layer 20 is disposed under the protective layer 16, and a protective layer 16 is disposed under the protective layer. And a lower structure 22 is provided at the bottom.

The protective layer 16 is formed on the outermost surface of the road and protects the surface layer 18 from impact and abrasion due to traffic of vehicles. As described above, by providing the protective layer 16 on the surface of the surface layer 18 on the road, the radio wave absorption performance on the surface layer 18 due to the change in the surface state and the thickness of the surface layer 18 due to wear and impact caused by excessive traffic of people and vehicles. Can be prevented from decreasing.

The protective layer 16 suppresses the reflection of electromagnetic waves on its surface and facilitates the incidence of electromagnetic waves.
For example, it is made of a material such as ordinary asphalt having electrical characteristics intermediate between air and the surface layer 18, or asphalt having electrical characteristics closer to air than the surface layer 18. Note that it is preferable that the protective layer 16 has a structure with many voids in order to make the incidence of electromagnetic waves easier.

The surface layer 18 as a structure disposed on the road having the electromagnetic wave absorbing function is made of a base material (asphalt, cement, concrete, etc.) such as an aggregate and a binder, which is made of a conductive or magnetic wave absorbing material. Are used alone or in combination to form an electromagnetic wave absorbing material having an electromagnetic wave absorbing function (energy attenuation).

The conductive electromagnetic wave absorbing material which is a dielectric material used here is preferably a highly durable carbon material or a metal material such as stainless steel. These materials are formed into a fibrous, bead-like or powder-like form. To use.

As a magnetic material such as a magnetic wave absorbing material used here, ferrite, permalloy, or the like is used in the form of, for example, granules, powders, lines, or plates.

Furthermore, the electromagnetic characteristics of the surface layer 18 can be adjusted by increasing or decreasing the amount of voids, the type of aggregate used (especially, specific gravity), and the like. Generally, increasing the amount of voids decreases the dielectric constant. It can be configured as follows.

Next, the surface layer 18 is made of an electromagnetic wave absorber (conductive fiber such as carbon fiber as an electromagnetic wave absorber, that is, a material that absorbs incident electromagnetic waves and causes a resistance loss, Having the property of causing so-called Joule heat loss, which converts energy into heat,
(Including those that cause energy loss due to induced current) will be described.

The electromagnetic wave absorber to be added to the granular material for forming the surface layer 18 is a carbon fiber 2 which is a conductive fiber.
In addition to 4 (carbon fiber), carbon-containing fiber, needle carbon, metal fiber such as stainless steel, or the like may be used. In particular, when carbon fiber is used, it has high environmental resistance and durability, so that it can be prevented from being affected by climate such as rainfall and snowfall.

Next, the length of the carbon fiber 24 when the carbon fiber 24 as an electromagnetic wave absorber is added to the granular material for forming the surface layer 18 will be described.

First, in order to expect a resistance loss when an electromagnetic wave is incident on the resistance loss element, the length (L) of the resistance loss element with respect to the wavelength λ of the electromagnetic wave to be absorbed (in vacuum). ) Is preferably L = nλ / 2 (n is a natural number).

Second, electromagnetic waves are transmitted through substances, media,
The wavelength is shorter than the wavelength in the air due to the wavelength shortening effect due to the electrical characteristics such as the dielectric constant of the resistance loss body (in this case, the carbon fiber 24) itself. In consideration of this point, the shortest length of the length (Lr) of the actually mixed resistance loss element is calculated on a theoretical formula,
Experiments have confirmed that an effective resistance loss effect (electromagnetic wave absorption effect) can be obtained when the shortest length (Lr) of the actually mixed resistance loss element is Lr ≧ λ / 10.

Next, the maximum length of the carbon fiber 24 as a resistance loss body added to the granular material forming the surface layer 18 will be described. The length (Lrm) of the resistance loss element actually mixed
The factors that define ax) include the following.

First, if the fiber length is much longer than the granular material to which the carbon fiber 24 is added, it becomes difficult to hold the carbon fiber 24 along the outer peripheral surface of the granular material.

Second, the surface layer 18 usually has a thickness of 30 to 50 mm at one time. Therefore, if the length of the carbon fiber 24 to be mixed is longer than the thickness of one application, the fiber is likely to be unevenly distributed in the surface layer after the application.

For the above reasons and the results of experiments, etc., by setting the maximum size of the carbon fiber 24 to 50 mm or less, the electromagnetic wave absorption characteristic becomes approximately −10 to −1 at 5.8 GHz.
It has been found that good results can be obtained at 5 dB (local conditions).

Next, the condition of the length of the carbon fiber 24 as the resistance loss body added to the granular material constituting the surface layer 18 that can absorb the electromagnetic wave of the predetermined wavelength λ to be absorbed most efficiently will be described. I do. This carbon fiber 24
Absorbs the electromagnetic wave of the predetermined wavelength λ most efficiently when the length of the carbon fiber 24 becomes a length that resonates with the electromagnetic wave of the predetermined wavelength λ.

That is, the length of the carbon fiber 24 is set to a length which is a natural number multiple of approximately λ / 2 with respect to the electromagnetic wave having a predetermined intensity λ and a low intensity used for communication, detection or measurement. Note that the carbon fiber 24 may be formed in a short linear shape so that the length becomes λ / 2n (n is a natural number).

Here, the wavelength of the electromagnetic wave used for communication, detection, or measurement is shortened when it enters the protective layer 16 and the surface layer 18 due to the wavelength shortening effect due to the electric characteristics such as the inherent dielectric constant. Further, the wavelength of the electromagnetic wave used for this communication, detection or measurement depends on the carbon fiber 2 mixed in the surface layer 18.
4, the wavelength is shortened by a wavelength shortening effect due to its electric characteristics such as a dielectric constant.

Therefore, the carbon fibers 24 mixed in the surface layer 18
Is set to a length that resonates with an electromagnetic wave having a predetermined wavelength λ in consideration of a wavelength shortening effect of the protective layer 16, the surface layer 18, and the carbon fiber 24 due to electrical characteristics such as a unique dielectric constant.

When the length of the carbon fiber 24 is set to a resonating length, for example, it is expected that the length of the electromagnetic wave will be shortened due to the electrical characteristics such as the dielectric constant of the material forming the surface layer 18. Is calculated, and further, from the electrical characteristics such as the dielectric constant of the carbon fiber 24, the wavelength expected to be shortened by the wavelength shortening effect of the electromagnetic wave is calculated, and the wavelength of the electromagnetic wave shortened under actual conditions is calculated. Predict.

Next, a carbon fiber 24 whose length is changed little by little near the predicted resonance length of the carbon fiber 24 is prepared, and a sample mixed into the surface layer 18 for each of these different lengths is prepared. I do.

Then, an electromagnetic wave of a predetermined wavelength λ used for communication, detection or measurement is irradiated to determine the absorption characteristics. At this time, the length of the carbon fiber 24 at which the peak effect of the absorption characteristic is obtained is set as the length of the carbon fiber 24 that resonates with an electromagnetic wave of a predetermined wavelength λ used for communication, detection or measurement.

When the carbon fiber 24 has such a length as to resonate with an electromagnetic wave having a predetermined wavelength λ, the surface layer 18 efficiently aims at the electromagnetic wave having a predetermined wavelength λ used for communication, detection or measurement. Since the electromagnetic wave is absorbed, it is possible to effectively prevent the electromagnetic wave interference of the unnecessary electromagnetic wave due to the reflection of the electromagnetic wave of the predetermined wavelength λ, and the communication, detection or measurement operation can be reliably performed.

Next, the optimum amount of the carbon fiber 24 as a resistance loss body added to the granular material as the electromagnetic wave absorbing material for forming the surface layer 18 will be described.

When the amount of the carbon fiber 24 added to the granular material of the base material is increased, the amount of electromagnetic wave reflected by the base material increases, and eventually, the base material becomes a reflector of electromagnetic waves. Experimentally, as the base material, a mixture of asphalt: aggregate = 5: 95 (weight ratio) was used, and the carbon fiber 24 (length 5 mm) added thereto was added to 0.5% (weight) of the granular material. Ratio), the result is that the reflection amount is increased.

Therefore, the electromagnetic wave absorbing function (energy attenuation)
Is suitable as an electromagnetic wave absorbing material having carbon fiber 24 mixed with a base material by 0.5% of a granular material as an aggregate.
% (Weight ratio) or less is considered desirable.

As shown in FIG. 2, the electromagnetic wave reflecting layer 20 disposed on a road having an electromagnetic wave absorbing function is formed by using a conductive electromagnetic wave absorbing material made of carbon fiber, metal fiber or the like. For example, a mesh formed of these materials (mesh size: 1 / 20th of the wavelength of the target electromagnetic wave)
The following is preferable) is provided on the surface of the base layer in the lower structure 22 behind the surface layer 18.

It is to be noted that the electromagnetic wave reflecting layer 20 may be provided in the base layer, or a conductive radio wave absorbing material may be sufficiently mixed into the surface portion or the whole of the base layer to constitute the reflecting layer. Alternatively, the electromagnetic wave reflector may be formed by sufficiently increasing the amount of the carbon fiber 24 added to the granular material of the base material, and may be arranged on the surface of the base layer in the lower structure 22 without any gap to form a reflective layer. good.

The lower structure 22 is a conventional pavement structure such as general sand or gravel.

Next, the reflected electromagnetic wave IW1 reflected on the upper surface of the surface layer 18 on the road having the electromagnetic wave absorbing function shown in FIG.
A configuration will be described in which the reflected electromagnetic wave OW1 that has been reflected through the surface layer 18 has an opposite phase and is attenuated by an internal loss due to the canceling action.

The reflected electromagnetic wave IW1 and the reflected electromagnetic wave OW
1, the thickness D of the surface layer 18 is set to D = λ.
(N + 1) / 4 COS θ (λ is the wavelength of the electromagnetic wave to be absorbed, n is a natural number, and θ is the incident angle of the electromagnetic wave).

With this configuration, the surface layer 18
The reflected electromagnetic wave IW1 reflected on the upper surface of the light-emitting device is incident on the surface layer 18 and then reflected by the electromagnetic-wave reflecting layer 20 and transmitted through the surface layer 18, so that the reflected electromagnetic wave IW1 and the reflected electromagnetic wave OW1 are opposite in phase. They cancel each other and disappear or attenuate.

Therefore, it is possible to reduce the reflection of electromagnetic waves on the road on which the surface layer 18 is provided.

In order to reverse the phase of the reflected electromagnetic wave OW1 on the surface layer 18, the thickness D of the surface layer 18 is set to λ (n + 1) /
Instead of setting 4COSθ, the electric length of the surface layer 18 is changed by changing the dielectric constant of the surface layer 18 to λ (n + 1) / 4C.
It may be configured to change and adjust to OSθ.

The electric length is changed to λ by changing the dielectric constant of the surface layer 18.
To change and adjust to (n + 1) / 4 COSθ, as shown in FIG.
It is assumed that an appropriate amount of bead-like carbon particles 26 (or carbon powder) may be mixed.

As a result, the dielectric constant of the pavement material forming the surface layer 18 is changed and adjusted to change the electrical length corresponding to the thickness of the surface layer 18 to λ (n + 1) / 4COSθ, and is reflected by the electromagnetic wave reflection layer 20. The phase of the reflected electromagnetic wave OW1 is reversed.

With such a configuration, the actual thickness of the surface layer 18 and the electrical length of the surface layer 18 can be made different from each other, so that the thickness of the surface layer 18 can be adapted to the strength condition of the road. The degree of freedom in road design can be increased.

Further, by constructing the road as shown in FIG. 3, in the electromagnetic wave absorbing material of the surface layer 18, the carbon fibers 24 and the carbon particles 26 cooperate with each other to generate an electromagnetic induction phenomenon, thereby causing an induced current. And the energy loss of the electromagnetic wave to be absorbed can be attenuated more.

Further, the thickness of the surface layer 18 on the road is made larger, so that the electromagnetic wave incident on the surface layer 18 is reflected by the electromagnetic wave reflection layer 20 and attenuates and disappears on the path passing through the surface layer 18. May be configured not to be radiated from the surface.

Alternatively, the portion of the surface layer 18 on the road may be increased to a necessary and sufficient thickness so that the electromagnetic wave incident from the surface of the surface layer 18 is absorbed on the path toward the bottom surface of the surface layer 18 and disappears. .

Next, a granular material having an electromagnetic wave absorbing property used for manufacturing an electromagnetic wave absorbing material will be described with reference to FIGS. 4 to 10 and FIGS.

The granular material 30 having the electromagnetic wave absorbing characteristics (electromagnetic wave absorbing function, energy damping function) is composed of a core 36 which is a lump of solid having a predetermined size, a base material disposed in a layer surrounding the core, and an electromagnetic wave absorbing member. The body is fixedly integrated.

The core 36 is formed by mixing coal ash powder and clay powder, forming a lump into a predetermined shape, firing and solidifying the lump, a lump of natural stone, a lump of granular material formed of cement, and the like. (Minimum particle size of about 1 mm or more).

As the base material, for example, a powder obtained by mixing a granulation aid of clay (powder) with coal ash is used.

The electromagnetic wave absorber is composed of a conductive electromagnetic wave absorbing material or a magnetic material alone or in combination.

As the conductive radio wave absorbing material used here, it is preferable to use a carbon material or stainless steel which is a dielectric material and has high durability. These materials are formed into a fibrous form, a bead form or a powder form. use.

As the magnetic material to be used, ferrite is used in the form of, for example, particles or powder.

The electromagnetic wave absorber absorbs an incident electromagnetic wave and causes a resistance loss, an electromagnetic wave absorber having a property of generating so-called Joule heat loss for converting energy of an electromagnetic wave into heat, and an energy loss due to an induced current. It can be composed of what causes it.

Further, as the electromagnetic wave absorber mixed into the granular material 30, carbon-containing fiber, needle carbon, metal fiber such as stainless steel, conductive fiber or the like may be used in addition to the carbon fiber 24 (carbon fiber). good. In particular, when carbon fiber is used, it has high environmental resistance and durability, so that it can be prevented from being affected by climate such as rainfall and snowfall.

The length, shape, additional amount, etc. of the carbon fiber 24 are the same as those of the surface layer 18 shown in FIG. 2 or FIG.

Further, the mixing ratio of the dielectric material or the magnetic material (electromagnetic wave absorber) to the base material is appropriately changed or adjusted, or the quality of the dielectric material or the magnetic material (electromagnetic wave absorber) to be mixed with the granular material 30 is changed. Thereby, the granular material 30 having desired various electromagnetic wave absorption characteristics can be obtained.

For example, depending on the use of the electromagnetic wave absorption characteristics, the granular material 30 having a relatively large amount of the carbon fiber 24 (electromagnetic wave absorber) may be formed, or the carbon fiber 24 may be relatively formed.
The granular material 30 in which the added amount of the (electromagnetic wave absorber) is reduced can be used.

Further, several kinds of carbon fibers 24 having different lengths are used.
Is prepared by mixing the granular material 30 for each length,
By appropriately combining and using these, it is possible to cope with a case where the frequency band of the electromagnetic wave to be absorbed is wide.

Further, when the granular material 30 is formed using the carbon fiber 24 (electromagnetic wave absorber), the length of the carbon fiber 24 may be changed and adjusted according to the frequency band of the electromagnetic wave to be absorbed. .

The electromagnetic characteristics of the granular material 30 can be adjusted by increasing or decreasing the amount of voids provided inside the granular material 30. In general, the dielectric constant can be reduced by increasing the amount of voids.

Next, the above-mentioned granular material 30 can be manufactured by the following two manufacturing methods.

In the first manufacturing method of the granular material, first, a manufacturing operation of a raw material measuring step is performed. The measurement process of this raw material is a dielectric material or a magnetic material (electromagnetic wave absorber)
And a base material (powder such as coal ash) and a granulation aid (powder of clay and the like) are each weighed to prepare a material having a required weight. Here, when the carbon fiber 24 (electromagnetic wave absorber) is used, its length is set according to the size of the core 36.

In the next mixing step, the required weight of the dielectric or magnetic material prepared in the raw material measuring step, the base material, and the granulation aid are charged into a mixer and mixed uniformly.

Next, in the adhering step of adhering the mixture of the electromagnetic wave absorber, the base material, and the granulation aid to the nucleus, a predetermined amount of the mixture of the electromagnetic wave absorber, the base material, and the granulation aid is surrounded around the core 36. Adhere in layers.

Next, in the granular forming step, around the core 36,
A predetermined amount of the mixture of the electromagnetic wave absorber, the base material, and the granulation auxiliary material adhered in a layer shape has a spherical shape as shown in FIG.
And a predetermined shape such as a small block having a random outer shape as shown in FIG.

Even when the granular material 30 is formed into a small lump having a random outer shape, a layer of the mixture of the electromagnetic wave absorber, the base material, and the granulation auxiliary material around the core 36 has a substantially uniform thickness. Therefore, the outer shape of each granular material 30 can be made substantially the same.

Next, in the firing step, the core 36, a dielectric material or a magnetic material, a base material, and a granulation auxiliary material, which are formed into a predetermined shape such as a sphere, a small lump, or a column, are subjected to a predetermined process. By baking at a temperature, a granular material 30 as shown in FIGS. 4 and 9 is manufactured.

As shown in FIGS. 9 and 10, in the light-weight granular material 30 manufactured as described above, a portion around the core 36 inside the lightweight granular material 30 has an infinite number of void portions (bubble-like space portions). It is composed of a side wall portion 30A.

For this reason, the side wall portion 30 in the granular material 30
In A, the carbon fiber 24 is in a trapped state, and forms a three-dimensional structure in which the carbon fiber 24 is homogeneously dispersed around 36 inside the granular material 30.

That is, in this lightweight granular material 30,
A shell-shaped side wall portion 30A is formed so as to surround the bubble-shaped space portion therein. Therefore, the carbon fibers 24 dispersed in the shell-shaped side wall portion 30A are arranged so as to face in a tangential direction corresponding to each curved surface inside the side wall portion 30A that partitions the bubble-like space. Will not be aligned in one direction.

Thus, the carbon fibers 24 are arranged so as to be oriented on average in all three-dimensional directions inside the shell-like side wall portion 30A surrounding each bubble-like space, and the shell-like shape is formed. The three-dimensional structure in which the carbon fibers 24 are uniformly distributed inside the side wall portion 30A and the carbon fibers 24 are uniformly dispersed is formed.

Furthermore, since the three-dimensional structure in which the carbon fibers 24 are uniformly dispersed is automatically formed in the firing step when the granular material 30 is manufactured, the carbon fibers 24 can be efficiently and easily dispersed in the granular material. 30 can be dispersed, and the weight of the granular material 30 itself can be reduced.

In the first method for producing the granular material 30 described above, a foaming aid such as calcium carbonate or silicon carbide is added to the powder as the base material in the mixing step in order to increase the foaming inside the granular material 30. May be mixed and then fired in a firing step to generate carbon dioxide gas to obtain bubbles.

This granular material 30 is made of a highly durable carbon material or stainless steel as a dielectric material mixed therein.
Fibers, beads, and granules can be used.

Further, by changing the mixing ratio of the dielectric material or the magnetic material mixed with the granular material 30, the electromagnetic wave absorbing action of the granular material 30 can be set according to the wavelength and the use environment. .

Further, the electromagnetic wave absorption performance of the granular material 30 can be adjusted by adjusting the amount of the dielectric material mixed into the granular material 30. The material and shape (diameter and length) of the dielectric material and the magnetic material are changed according to the frequency of the electromagnetic wave to be absorbed. Also,
The absorption characteristics can be changed by changing the particle size (shape) of the granular material 30 itself.

The granularity and the outer shape of the granular material 30 can be freely set.

Further, the first method for producing the above-mentioned granular material 30
In addition to the above manufacturing method, the granular material 30 may be manufactured by the following second manufacturing method.

In the second manufacturing method, a powder and a fiber material are alternately adhered to the outside of the core 36 and granulated to a required size.

Therefore, in the second manufacturing method, first, the core 36, the electromagnetic wave absorber (here, the carbon fiber 24 is used), the base material (powder such as coal ash), and the granulation auxiliary material (clay) And the like) are separately prepared.

Next, in the attaching step, as a first operation, as shown in FIG. 13, the carbon fibers 24 as the electromagnetic wave absorber are attached uniformly on the entire outer peripheral surface of the core 36.

At this time, a small amount of moisture or a binder material may be used to enhance the effect of attaching the carbon fibers 24 to the outer peripheral surface of the core 36.

As a result, the carbon fibers 24 are attached to the entire outer peripheral surface of the core 36, and each carbon fiber 24
6 form a three-dimensional structure that is homogeneously dispersed in the tangential direction at each contact portion on the outer peripheral surface of each carbon fiber 2.
The orientation of No. 4 will not be aligned in one direction.

Next, as a second operation, as shown in FIG. 14, the base material and the granulation auxiliary material are uniformly distributed on the entire outer peripheral surface of the core 36 with the carbon fiber 24 adhered to the entire outer peripheral surface. Is adhered in layers.

At this time, a small amount of a mixture of the base material and the granulation auxiliary material is further applied to the core 36 with the carbon fiber 24 adhered to the outer peripheral surface thereof in order to enhance the adhesion effect. Of water or a binder material may be used.

Next, as a third operation, as shown in FIG. 15, the carbon fiber 24 was attached to the outside of the core 36 in the same manner as described above, and the mixture of the base material and the granulation auxiliary material was overcoated. The carbon fibers 24 as the electromagnetic wave absorber are uniformly attached to the entire outer peripheral surface.

Next, as a fourth operation, as shown in FIG. 16, the carbon fiber 24, the mixture of the base material and the granulation auxiliary material, and the three layers And a mixture of the base material and the granulation auxiliary material is uniformly applied to the entire outer peripheral surface of the material, and the material is applied in a layered manner to obtain a granular material 3.
0.

The granular material 30 is formed by adhering a layer of carbon fiber 24 and a layer of a mixture of the base material and the granulation aid alternately on the outer peripheral surface of the core 36 a required number of times as described above. By doing so, it is granulated to a predetermined size.

In the granulating operation of the granular material 30,
First, a mixture of the base material and the granulation auxiliary material may be attached to the outer peripheral surface of the core 36, and then the carbon fiber 24 may be attached.

Further, the carbon fiber 24 or a mixture of the base material and the granulation auxiliary material is adhered so as to be applied twice, or adhered so as to be applied a plurality of times. A mixture with an auxiliary material or the carbon fiber 24 may be attached.

When the granulating operation of the granular material 30 is performed as described above, the operation of stirring and mixing the carbon fiber 24, the base material, and the granulation auxiliary material is not performed. Therefore, it is possible to prevent the carbon fibers 24 from breaking or leaving only the plurality of carbon fibers 24 as a lump.

If necessary, the core 36 may be used as described above.
A predetermined amount of the mixture of the electromagnetic wave absorber, the base material and the granulation auxiliary material is adhered in a layered form around the shape of a circle, a spherical shape as shown in FIG. 8 (in this case, in order to make the core 36 a similar shape slightly smaller than the outer shape of the granular material 30,
The granular material 30 is formed in a small columnar shape. ) May be formed in a predetermined shape.

Next, in the firing step, the nucleus 36, the carbon fiber 24, the base material, and the granulation aid formed into granules having a predetermined shape such as a sphere, a small lump, or a column at a predetermined temperature. By baking, a granular material 30 as shown in FIG. 4, FIG. 6, FIG. 7, FIG.

In this firing step, the granular material 30 may be solidified as it is, or the granular material 30 may be foamed into a layer of the mixture of the base material and the granulation auxiliary material therein. May be configured so as to create a space portion.

Here, when the granular material 30 is solidified as it is, the carbon fibers 24 are arranged in a tangential direction with respect to each point on the outer peripheral surface of the core 36.
The carbon fibers 24 and the layer of the mixture of the base material and the granulation aid, which are arranged so as to be oriented in almost all three-dimensional directions on a substantially average basis, have a substantially uniform density around the core 36. And the carbon fibers 24 form a three-dimensional structure in which the carbon fibers 24 are homogeneously dispersed, so that the orientation of the carbon fibers 24 is not aligned in one direction.

When the granular material 30 forms a cellular space in the layer of the mixture of the base material and the granulation auxiliary material therein, a shell-like side wall is formed so as to surround the cellular space. A portion 30A is formed.

In this case, a foaming material (calcium carbonate, silicon carbide, or the like) is further mixed with the base material and the granulation auxiliary material, and the nuclei 36 formed into granules, the carbon fibers 24, and the base material are formed in the firing step. And a mixture of a foaming material and a foamed material are fired at a predetermined temperature to generate carbon dioxide gas, thereby forming a more porous structure with a myriad of voids (bubble-shaped space portions) and side wall portions 30A by bubbles formed inside. May be.

[0132] The granular material 30 thus made porous is formed by the carbon fibers 24 dispersed in the shell-like side wall portion 30A. Are arranged so as to face in a tangential direction corresponding to each portion of the curved surface.

Accordingly, the carbon fibers 24 are arranged so as to be oriented substantially in all three-dimensional directions in the shell-like side wall portion 30A surrounding each bubble-like space portion, and the shell-like wall portions 30A. The three-dimensional structure in which the carbon fibers 24 are uniformly distributed inside the side wall portion 30A and the carbon fibers 24 are uniformly dispersed is formed.

That is, in the granular material 30, the carbon fibers 24 are oriented in various directions around the nucleus 36 inside the granular material 30 and are arranged in an averagely dispersed manner. Will not be aligned in one direction.

The granular material 3 constructed as described above is used.
0 has a bubble-shaped space inside, so that its own weight can be reduced.

The granular material 30 configured as described above causes the electromagnetic wave transmitted from the surface of the granular material 30 to interfere with the carbon fiber 24 which is a dielectric material or a magnetic material inside the granular material 30, thereby promoting the internal loss and increasing the electromagnetic wave. Get the absorption effect.

Further, since many void portions in the granular material 30 exist uniformly in all directions, the granular material 3
Even when the angle of incidence on the zero surface is small, surface reflection hardly occurs, so that the electromagnetic wave W can easily enter the granular material 30 and be absorbed.

Also, concrete, asphalt, and resin mixture materials obtained by incorporating the lightweight granular material 30 as a structural material (aggregate) can be used as lightweight building materials such as walls, floors and roofs by molding them into panels.

The light-weight building material constructed as described above is used as a building material in a facility around a tollgate on a toll road, in a tunnel pit, or in any other place where electromagnetic waves are irradiated. Can be used as a technique for minimizing

As shown in FIGS. 2 and 3, the thickness of the layer containing the granular material 30 (the surface layer 18) is adjusted to adjust the thickness of the electromagnetic wave reflecting material (electromagnetic wave reflecting layer 2) on the rear surface.
The incident wave reflected at 0) is converted into the opposite phase, and an internal loss due to the canceling action can be obtained.

The electromagnetic characteristics of the granular material 30 can be adjusted by increasing or decreasing the amount of voids provided inside the granular material 30. In general, the dielectric constant can be reduced by increasing the amount of voids.

Next, a description will be given of a case where the surface layer 18 as a structure on a road is formed by using the granular material 30 having the electromagnetic wave absorption characteristics formed by mixing the carbon fibers 24 as described above.

In this case, a predetermined large number of the granular materials 30 having the electromagnetic wave absorbing characteristics constituted by mixing the carbon fibers 24 are prepared, a predetermined appropriate amount of the binder is added thereto, and these are mixed well by mixing well. Fig. 5
The surface layer 18 of the road as shown in FIG.

By configuring the surface layer 18 in this manner, when the granular material 30 and the binder 34 are mixed, each granular material 30 is stably dispersed within the range where the surface layer 18 is formed. Along with this, the carbon fibers 24 mixed into each of the granular materials 30 are also dispersed on average within the range for forming the surface layer 18 to form the surface layer 18 in a state as shown in FIG.

Next, the surface layer 18 is integrated with three layers having different packing densities of carbon fibers 24 so that electromagnetic waves can easily enter from the surface side of the surface layer 18 and reduce the reflection of the electromagnetic waves in FIG.
1 will be described.

[0146] In this case, the carbon fiber 2 containing the largest amount of carbon fiber 24 compared to the others inside the granular material 30
4, a granular material 30 having a medium content of carbon fibers 24 mixed with medium carbon fibers 24 inside the granular material 30 and a granular material 30 having a highest content of The granular material 30 having the lowest content of carbon fiber 24 mixed with the least carbon fiber 24 as compared with others
And prepare.

Using the granular material 30 having the highest carbon fiber 24 content, the surface layer 1 is in a state where the mixing ratio with other aggregates is the highest (the state where the density of the granular material 30 is high).
8 constitute the lowermost layer 18A (third layer).

Next, the intermediate layer 18B (second layer) of the surface layer 18 is formed by using the granular material 30 having a medium content of the carbon fiber 24 and having a medium mixing ratio with other aggregates. Constitute.

Next, the uppermost layer 18C (first layer) of the surface layer 18 is constituted by using the granular material 30 having the smallest content of the carbon fiber 24 and in a state where the mixing ratio with other aggregates is the lowest. Then, the surface layer 18 having an integral structure as illustrated in FIG. 11 is formed.

By adjusting only the content of the carbon fibers 24 or the mixing ratio with the other aggregates, the lowermost layer 1 of the surface layer 18 was adjusted.
8A (third layer), intermediate layer 18B (second layer), top layer 18
C (first layer) may be formed.

As can be seen from the diagram shown in FIG. 12, in the surface layer 18 having the above-mentioned integral structure, the first layer on the front side has the lowest content of carbon fibers 24, so that the first layer on the front side has Since the electromagnetic wave incident on the layer easily enters the inside of the surface layer 18, the electromagnetic wave can be absorbed while reducing the reflection of the electromagnetic wave on the surface of the surface layer 18. Then, in the surface layer 18 having this integral structure, the second layer having a medium content of the carbon fiber 24 gradually absorbs the electromagnetic wave while passing the electromagnetic wave, and the third layer having the highest content of the carbon fiber 24 is formed. Can sufficiently absorb electromagnetic waves.

Next, a road portion constructed of a pavement material which is an electromagnetic wave absorbing material using the above-mentioned particulate material having electromagnetic wave absorbing characteristics was formed in at least a required range of the road in the automatic toll collection point shown in FIG. The operation and effect at this time will be described.

The pavement material used here is a structure that absorbs the millimeter wave of the radar (including the carbon fiber 24 having a length corresponding to absorb the millimeter wave of the radar, and the radio communication of the automatic toll collection device 12). It is configured to include a carbon fiber 24 having a length corresponding to the electromagnetic wave emitted from the device, for example, in a frequency band of 5.80 GHz.)

In this automatic toll collection station, a vehicle 14 traveling on the road toward the automatic toll collection device 12 by emitting millimeter waves from a vehicle detection radar of the automatic toll collection device 12 disposed there. Is detected.

At this time, the millimeter waves emitted from the radar device are absorbed by the road having the electromagnetic wave absorbing function, so that the radar device does not malfunction properly due to electromagnetic wave disturbance due to unnecessary electromagnetic waves reflected on the road. The vehicle 14 can be detected.

When the radar device of the automatic toll collection device 12 detects the vehicle 14 at a predetermined position in this way, the wireless communication device of the automatic toll collection device 12 operates, for example, at 5.80 GHz.
Vehicle 1 using communication signal MW which is a radio wave of the frequency band
The wireless communication is performed with the automatic toll payment device mounted on the device 4 to execute a toll collection process.

At this time, the 5.80 GHz radio wave emitted from the wireless communication device of the automatic toll collection device 12 is absorbed when it hits a road having an electromagnetic wave absorption function.

[0158] Therefore, 4.
Due to the electromagnetic wave interference that the 80 GHz radio wave is reflected on the road and received by a following vehicle approaching immediately after the vehicle 14 detected at the predetermined position, the charge of the vehicle 14 detected at the predetermined position It is possible to effectively prevent an erroneous operation in which the collection processing and the toll collection processing of the following vehicle are performed simultaneously.

Although not shown, when a pavement material manufactured by using the granular material 30 having the electromagnetic wave absorbing characteristics of the present embodiment is used in a driving support system of an automobile,
For example, a part of the road within a range necessary to remove an electromagnetic interference around a lane marker installed at each predetermined position on the road along the traveling route of the automobile on the road, a pavement material having an electromagnetic wave absorbing function. Constitute.

That is, the road is provided with a pavement material having an electromagnetic wave absorbing function in a circle having a predetermined radius surrounding the lane marker, or a pavement material having an electromagnetic wave absorbing function in an oval shape along the longitudinal direction of the road. .

With this configuration, a detection device such as a radar of a driving support device mounted on an automobile running on the road can properly detect the position of the lane marker without receiving an electromagnetic wave obstacle and perform proper driving. Route can be detected. Furthermore, various communication can be appropriately performed between the communication device of the lane marker disposed on the road and the vehicle without receiving the electromagnetic interference.

In the above-described embodiment, the structure in which the pavement material using the particulate material 30 having the electromagnetic wave absorbing property is used for pavement of the road has been described. It can be used as a material for structures.

That is, the granular material 30 having the electromagnetic wave absorbing property is a material forming the floor of a parking lot, a material forming the floor of a building, a material forming a runway, or a material forming the floor of a hangar. It can be used as a configurable material for tunnels, tunnels, and other structures that are irradiated with electromagnetic waves.

Further, the granular material 3 having electromagnetic wave absorption characteristics
0 can be manufactured using asphalt, concrete, resin binder, etc. as a binder 34, and can be formed using the mixture according to the shape and required thickness of the structure at the construction site. Various structures can be built.

As described above, by using the granular material 30 having the electromagnetic wave absorbing property, the ITS related technology using the communication using the electromagnetic wave in the facilities around the tollgate of the road, in the tunnel pit, and other general places where the electromagnetic wave is irradiated. Etc.
Harmful scattered electromagnetic waves can be efficiently removed.

[0166]

First, the particulate material having the electromagnetic wave absorbing characteristics of the present invention is obtained by attaching an electromagnetic wave absorber that absorbs electromagnetic waves to a base material, which is uniformly dispersed and mixed around a core. And solidify.

As a result, the electromagnetic wave absorbers are dispersed and arranged around the nucleus inside the granular material, so that it is possible to obtain a granular material having stable electromagnetic wave absorbing characteristics and stable electromagnetic wave absorbing characteristics. Can be. In addition, the granular material having the electromagnetic wave absorption characteristics has a function of favorably absorbing electromagnetic waves. Further, by forming a layer of a mixture of the base material and the electromagnetic wave absorber with a substantially uniform thickness around the core, there is an effect that the outer shape and size of the granular material can be made uniform.

Secondly, the method of the present invention for producing a granular material having electromagnetic wave absorbing properties is characterized in that a material obtained by uniformly dispersing and mixing electromagnetic wave absorbers for absorbing electromagnetic waves in a base material is provided around a lump of nuclei. After that, a mixture of the base material and the electromagnetic wave absorber is adhered to the periphery of the nucleus, and then solidified and manufactured integrally.

As a result, it is possible to easily produce a granular material in which the electromagnetic wave absorber is evenly dispersed in the substrate solidified around the core. Further, the granular material can be manufactured with a uniform outer shape and size. Therefore, there is an effect that a granular material having an electromagnetic wave absorbing characteristic can be mass-produced with stable quality. .

Third, a method for producing a granular material having electromagnetic wave absorbing properties is as follows. A material obtained by uniformly dispersing and mixing an electromagnetic wave absorber for absorbing electromagnetic waves and a foaming material in a base material is used to form a block of cores. After being adhered to the surroundings, by baking in a state where the base material and the electromagnetic wave absorber are mixed around the nucleus, it is solidified integrally in a state of foaming in the part including the base material Manufacturing.

As a result, it is possible to easily produce a granular material in which the electromagnetic wave absorber is evenly dispersed in a substrate solidified in a state of being foamed around the core. Further, the granular material can be manufactured with a uniform outer shape and size. Since the electromagnetic wave absorbers arranged on the side walls between the voids inside the granular material having the electromagnetic wave absorption characteristics are arranged in an averagely dispersed manner corresponding to the surface partitioning the voids, the electromagnetic waves are well absorbed. There is an effect that can be.

Fourth, in the granular material having electromagnetic wave absorbing properties of the present invention, an electromagnetic wave absorber is arranged outside a lump of nuclei in a layer containing the nuclei, and a base material is further arranged outside the nuclei. Are arranged in a layer shape including the electromagnetic wave absorber, and the layer of the electromagnetic wave absorber and the layer of the base material constitute a laminated structure.

As a result, the electromagnetic wave absorber is arranged in a layer around the nucleus and then dispersed in the vicinity thereof.
The electromagnetic wave absorber can be dispersed evenly over the entire outside of the nucleus. As a result, the property of absorbing the electromagnetic wave of the granular material is made more uniform in each part of the outer periphery of the granular material, and there is an effect that the electromagnetic wave absorbing characteristics of the granular material are stabilized and the reliability can be further improved.

Fifth, in a method for producing a granular material having electromagnetic wave absorbing properties, an electromagnetic wave absorber for absorbing electromagnetic waves is attached to the outside of a core, and a base material or a material containing the same is provided outside the core. Adhered, thereby, outside of the nucleus, an electromagnetic wave absorber and a substrate or a material containing the same is adhered and laminated,
In this state, the granular material is integrally solidified.

Thus, since the electromagnetic wave absorber is arranged in a layer around the core, it is possible to easily produce a granular material in which the electromagnetic wave absorber is dispersed evenly over the entire outside of the core. At the same time, since the electromagnetic wave absorbers are dispersed and arranged around the nucleus inside the granular material on average, the granular material having electromagnetic wave absorption characteristics has a function of absorbing electromagnetic waves well, and the electromagnetic wave absorption It is possible to obtain a granular material having stable electromagnetic wave absorption characteristics with stable characteristics. Furthermore, since the respective layers of the base material and the electromagnetic wave absorber are formed with a substantially uniform thickness around the nucleus, there is an effect that the outer shape and size of the granular material can be made uniform.

Sixth, in a method for producing a granular material having electromagnetic wave absorbing properties, an electromagnetic wave absorber that absorbs electromagnetic waves is attached to the outside of a lump of nuclei, and a base material and a foaming material or these materials are attached to the outside of the nuclei. The material containing is adhered, and then, on the outside of the core, the electromagnetic wave absorber and the base material and the foaming material or a material containing these are adhered and fired in a laminated state, thereby foaming the portion including the base material. And solidify integrally to produce a granular material.

As a result, the side walls between the voids in the substrate solidified in a state of being foamed around the core,
Since the electromagnetic wave absorber is arranged and arranged to be dispersed on an average in accordance with the surface partitioning the gap, the electromagnetic wave can be favorably absorbed. Therefore, it is possible to mass-produce the granular material having the electromagnetic wave absorption characteristic with stable quality, and to provide a low-priced product.

Seventh, the granular material having the electromagnetic wave absorbing characteristics of the present invention is constituted by using carbon fibers as the granular material having the electromagnetic wave absorbing characteristics.

As a result, the design can be changed so as to obtain the required electromagnetic wave absorption characteristics only by changing and adjusting the length of the carbon fiber in accordance with the wavelength of the electromagnetic wave to be absorbed. Even if the wavelength is different, there is an effect that it is possible to cope without changing the weight of the granular material using the carbon fiber.

[Brief description of the drawings]

FIG. 1 shows a granular material having electromagnetic wave absorption characteristics of the present invention;
It is a perspective view which shows schematic structure of the automatic toll collection point which concerns on embodiment in the manufacturing method.

FIG. 2 shows a granular material having an electromagnetic wave absorbing property of the present invention;
It is sectional drawing which shows the cross-sectional structure of the road which has the electromagnetic wave absorption function which concerns on embodiment in the manufacturing method.

FIG. 3 shows a granular material having an electromagnetic wave absorbing characteristic of the present invention;
It is sectional drawing which shows the other sectional structure of the road which has the electromagnetic wave absorption function which concerns on embodiment in the manufacturing method.

FIG. 4 is a front view showing a granular material according to an embodiment of the granular material having electromagnetic wave absorption characteristics of the present invention.

FIG. 5 is a longitudinal sectional view showing a state in which the particulate material having electromagnetic wave absorption characteristics of the present invention is integrated with a binder.

FIG. 6 is a perspective view showing a state in which a granular material having electromagnetic wave absorption characteristics of the present invention is formed into a spherical shape.

FIG. 7 is a perspective view showing a state when a granular material having electromagnetic wave absorption characteristics of the present invention is formed in a random lump shape.

FIG. 8 is a perspective view showing a state in which a granular material having electromagnetic wave absorption characteristics of the present invention is formed in a columnar shape.

FIG. 9 is a longitudinal sectional view showing a granular material having electromagnetic wave absorption characteristics of the present invention.

FIG. 10 is an enlarged longitudinal sectional view showing a part of a porous electromagnetic wave absorbing material having electromagnetic wave absorbing characteristics of the present invention.

FIG. 11 is a cross-sectional view showing a part of a structure having a three-layer structure using a granular material having electromagnetic wave absorption characteristics of the present invention.

FIG. 12 is an explanatory diagram illustrating an electromagnetic wave absorption state in a structure having a three-layer structure using the granular material having electromagnetic wave absorption characteristics of the present invention.

FIG. 13 is a schematic cross-sectional view showing a state in which carbon fibers are attached to the entire outer peripheral surface of the core according to the embodiment of the method for producing a granular material having electromagnetic wave absorption characteristics of the present invention.

FIG. 14 shows a base material and a granulation auxiliary material on the entire outer peripheral surface of a core having carbon fibers adhered to the entire outer peripheral surface thereof according to the embodiment of the method for producing a granular material having electromagnetic wave absorption characteristics of the present invention. FIG. 3 is a schematic cross-sectional view showing a state in which a mixture of is mixed and attached in a layer.

FIG. 15 is an outer peripheral surface of a method of manufacturing a granular material having electromagnetic wave absorption characteristics according to an embodiment of the present invention, in which carbon fibers are attached to the outside of a core and further overcoated with a mixture of a base material and a granulation auxiliary material. It is a schematic sectional view showing the state where carbon fibers as an electromagnetic wave absorber were made to adhere to the whole.

FIG. 16 shows a method for producing a granular material having electromagnetic wave absorption properties according to an embodiment of the present invention, in which three layers of carbon fibers, a mixture of a base material and a granulation auxiliary material, and three layers of carbon fibers are further stacked outside the core according to the embodiment. FIG. 3 is a schematic cross-sectional view showing a state in which a mixture of a base material and a granulation auxiliary material is adhered in a layer on the entire outer peripheral surface of the adhered material to form a granular material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Automatic toll collection apparatus 18 Surface layer 18A Bottom layer 18B Intermediate layer 18C Top layer 20 Electromagnetic wave reflection layer 24 Carbon fiber 26 Carbon particles 30 Granular material 30A Side wall portion 34 Binding material 36 Nucleus

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Takahashi 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside the Technical Research Institute, Takenaka Corporation (72) Inventor Masato Yamamoto 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside Takenaka Corporation Technical Research Institute (72) Inventor Toshio Saito 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside Takenaka Corporation Technical Research Institute (72) Inventor Kenichi Haragawa 1-5 Otsuka, Inzai City, Chiba Prefecture No. 1 Inside Takenaka Corporation Technical Research Institute (72) Inventor Takeshi Kunishima 21-1 Ginza, Chuo-ku, Tokyo Inside the Takenaka Road (72) Inventor Kenichi Yoshimura 8-chome, Ginza, Chuo-ku, Tokyo No. 21 1 F-term in Takenaka Road Co., Ltd. (reference) 5E321 AA41 BB21 BB60 GG05 GG11

Claims (7)

[Claims] 1. A mass of a core, a base material adhered and solidified around the core, and an electromagnetic wave absorber that absorbs electromagnetic waves uniformly dispersed and mixed in the base material. A granular material having electromagnetic wave absorption characteristics characterized by the following. 2. A step of adhering a mixture of electromagnetic wave absorbers for absorbing electromagnetic waves, which are uniformly dispersed and mixed in a base material, around a core of the mass, the base material and the electromagnetic wave around the core. A method for producing a granular material having electromagnetic wave absorption characteristics, comprising: a step of integrally solidifying a state in which a mixture of an absorber and a mixture is adhered. 3. A step of adhering, in a base material, a mixture of an electromagnetic wave absorber that absorbs electromagnetic waves and a foam material, which is uniformly dispersed and mixed, around a core of a lump; By firing in a state in which the base material and the electromagnetic wave absorber are mixed,
And solidifying integrally in a state where it is foamed in a portion including the base material. A method for producing a granular material having electromagnetic wave absorption characteristics, comprising: 4. A mass of nuclei, an electromagnetic wave absorber outside the nucleus and arranged in a layer including the nucleus, and an electromagnetic wave absorber outside the nucleus and arranged in a layer outside the nucleus and including the nucleus A granular material having electromagnetic wave absorption characteristics, comprising: a base material; and a layer of the electromagnetic wave absorber and a layer of the base material having a laminated structure. 5. A step of attaching an electromagnetic wave absorber that absorbs electromagnetic waves to the outside of the lump of nuclei; a step of attaching a substrate or a material containing the same to the outside of the nucleus; A step of solidifying the electromagnetic wave absorber and the base material or a material containing the same while adhering and laminating the same, and a method of producing a granular material having electromagnetic wave absorption characteristics. 6. A step of attaching an electromagnetic wave absorber that absorbs electromagnetic waves to the outside of the lump of nuclei, a step of attaching a base material and a foam material or a material containing these to the outside of the nuclei, A step in which the electromagnetic wave absorber and the base material and the foaming material or a material containing them are adhered and fired in a laminated state on the outside, and solidified integrally in a foamed state in a portion including the base material. A method for producing a granular material having electromagnetic wave absorption characteristics, comprising: 7. The particulate material having electromagnetic wave absorbing characteristics according to claim 1, wherein the electromagnetic wave absorber is a carbon fiber.