WO2007058164A1

WO2007058164A1 - Radio wave absorber and process for producing the same

Info

Publication number: WO2007058164A1
Application number: PCT/JP2006/322642
Authority: WO
Inventors: Katsunori Hosotani; Masahiro Fukui; Toshio Kudo
Original assignee: Mitsubishi Cable Industries, Ltd.
Priority date: 2005-11-21
Filing date: 2006-11-14
Publication date: 2007-05-24
Also published as: JPWO2007058164A1

Abstract

A radio wave absorber that can be easily produced, being capable of broadband radio wave absorption. There is provided a radio wave absorber comprising matlike fiber assembly (1) from multiple fibers (F) entangled together and multiple radio wave absorbing parts (2) composed of fibers (F) having conductive material (3) adhering thereto, which radio wave absorbing parts (2) are each formed in the fiber assembly (1) so as to have the cross section enlarged from one surface (1a) side toward the opposite surface (1b) side of the fiber assembly (1).

Description

Specification

Radio wave absorber and manufacturing method thereof

Technical field

The present invention relates to a radio wave absorber and a manufacturing method thereof.

Background art

[0002] Generally, a radio wave absorber is disposed on the wall or ceiling of an anechoic chamber for testing products such as electrical products. Some of these wave absorbers are formed in a pyramid or wedge shape with improved radio wave characteristics over a wide frequency band.

[0003] For example, a radio wave absorber (see Patent Document 1) in which a large number of pyramidal resin foams are arranged in a lattice-like member, or a conical filling hole in a plate-like dielectric made of polystyrene. There is a radio wave absorber (see Patent Document 2) formed by filling and filling the hole with a radio wave absorbing material such as carbon powder.

[0004] Although it is not pyramid-shaped or wedge-shaped, it has a radio wave absorption layer formed by attaching a conductive material to a mat-like glass fiber layer, and the radio wave absorption layer and the sound wave absorption layer are laminated. There is a sound wave / wave absorber formed (see Patent Document 3).

Patent Document 1: Japanese Patent Laid-Open No. 2000-286588

Patent Document 2: JP-A-6-268394

Patent Document 3: Japanese Patent Laid-Open No. 2003-86988

Disclosure of the invention

Problems to be solved by the invention

[0005] By the way, in recent years, electronic devices that emit radio waves (electromagnetic waves) such as personal computers and mobile phones have increased. For this reason, it is required to install the above-mentioned electromagnetic wave absorber even in the room such as a building or a general house.

[0006] However, there are the following difficulties in using a conventional radio wave absorber on the wall and ceiling of an indoor space such as an intelligent building or a general house where a wireless LAN system is introduced.

(i) In the electromagnetic wave absorber as described in Patent Document 1 above, a large number of pyramidal resin foams are used. The wall surface force also protrudes, making it difficult to use the indoor space effectively.

(ii) In the radio wave absorber as described in Patent Document 2, it takes time and effort to form a filling hole or cover the filling hole, and it is difficult to manufacture easily.

(iii) In the sound wave / radio wave absorber as described in Patent Document 3 above, the radio wave absorber layer is formed by adhering a conductive material to the entire glass fiber layer. Since the absorption layer is not a pyramid type, it cannot absorb broadband radio waves. In addition, the radio wave absorption layer and the sound wave absorption layer must be divided into a two-layer structure, which requires a large installation space, resulting in a narrow indoor space.

[0007] Therefore, a main object of the present invention is to provide a radio wave absorber that can be easily manufactured and can absorb radio waves in a wide band and a method for manufacturing the same.

Means for solving the problem

[0008] In order to achieve the above object, a radio wave absorber according to the present invention includes a mat-like fiber assembly formed by entwining a plurality of fibers, and one side of the fiber assembly on the fiber assembly. It is formed into a three-dimensional shape in which at least the outline part of the cross-sectional shape gradually expands from the other side toward the other side! /! And includes a plurality of radio wave absorbers with conductive materials attached to the fibers! /, It is something.

[0009] Note that, in the above configuration, each radio wave absorber is disposed in a layered block in which a plurality of mat-like fiber assemblies formed by entwining a plurality of fibers are stacked, and a direction orthogonal to the stacking direction of the fiber assemblies. One-surface-side force in the surface can be formed into a three-dimensional shape in which at least the contour portion of the cross-sectional shape of the radio wave absorbing portion gradually expands by directing the other-surface side.

[0010] The fiber assembly is made of fiber strength of an inorganic material such as glass wool or rock wool. In addition, the fiber aggregate may be one having the fiber strength of the organic material, but the inorganic material is more resistant to heat and heat cycle. On the other hand, with organic materials, dimensional changes occur due to thermal history, and there is a risk that the absorption performance will be adversely affected.

Furthermore, the radio wave absorber according to the present invention can be used for a radio wave absorber wall for preventing radio wave interference in a room where a wireless LAN is installed.

[0012] In the method for manufacturing a radio wave absorber according to the present invention, a discharge port of a cylinder containing a conductive paint is brought into contact with one surface of a mat-like fiber assembly formed by tying a plurality of fibers, and the discharge port is The conductive paint is extruded by a piston so that the conductive paint spreads so as to spread from one side of the fiber assembly to the other side, and the discharge penetration step of the conductive paint is performed as described above. In this method, a plurality of radio wave absorbers are formed by repeatedly or simultaneously performing a plurality of predetermined portions, and then curing the conductive paint.

[0013] Further, a discharge port provided in a container containing a conductive paint is brought into contact with one surface of a mat-like fiber assembly formed by entwining a plurality of fibers, and a suction cylinder portion is provided on the other surface side of the fiber assembly. The conductive paint is evacuated to discharge the discharge loca, and the conductive paint is permeated so that the force on one side of the fiber assembly also spreads toward the other side. The process is repeated or simultaneously performed at a plurality of predetermined portions of the fiber assembly V, and then the conductive paint is cured to form a plurality of radio wave absorbers.

[0014] Further, a conductive paint is put into the cylinder portion of a syringe having a syringe needle, a cylinder portion, and a piston, and the inside of the mat-like fiber assembly formed by tying a plurality of fibers around the tip of the syringe needle While pushing in, the tip force of the injection needle is pushed out by the piston to penetrate the conductive paint so that the force on one side of the fiber assembly spreads toward the other side. The discharge permeation step is repeated or simultaneously performed at a plurality of predetermined portions of the fiber assembly, and then the conductive paint is cured to form a plurality of radio wave absorbers.

[0015] In addition, a conductive paint is put into the cylinder portion of a syringe having a syringe needle, a cylinder portion, and a piston, and the tip of the syringe needle is formed from one surface to the inside through a plurality of fibers. The tip of the injection needle is placed in the vicinity of the other surface of the fiber assembly, and the conductive paint is drawn from the tip of the injection needle to the piston while the injection needle is pulled out of the fiber assembly. The conductive coating is permeated so as to contract from the other side of the fiber assembly toward the other side, and the discharge penetration step of the conductive coating is performed at a plurality of predetermined portions of the fiber assembly. It is a method in which a plurality of radio wave absorbers are formed by repeatedly or simultaneously performing, and then curing the conductive paint.

[0016] Further, the first plate having a plurality of discharge holes, and a plurality of suction holes each having a smaller diameter than the discharge holes of the first plate, each of the plurality of suction holes being the first plate. A second plate disposed opposite the first plate so as to correspond to the plurality of discharge holes of the plate; A mat-like fiber assembly formed by entwining a large number of fibers is sandwiched in between, and conductive paint is accumulated in each discharge hole of the first plate, and the conductive paint is drawn from each suction hole of the second plate. Discharge permeation so that the conductive paint is infiltrated by contracting from the surface on the first plate side to the surface on the second plate side by discharging the discharge hole force and discharging the conductive paint. In this method, the work is performed sequentially or simultaneously for each pair of the discharge hole and the suction hole corresponding to each other, and then the conductive paint is cured to form a plurality of radio wave absorbers.

The invention's effect

[0017] The present invention has the following remarkable effects.

[0018] According to the radio wave absorber and the manufacturing method thereof according to the present invention, the radio wave absorber can be easily manufactured and the radio wave can be absorbed in a wide band.

That is, unlike a conventional wave absorber, a complicated manufacturing process of forming a conical filling hole in a plate-like dielectric material or applying a lid is not required, and a conductive material ( By simply attaching a conductive paint, it is possible to easily form a large number of radio wave absorbers (conical or the like) that have a wide cross-sectional shape and exhibit broadband electromagnetic wave absorption performance.

Furthermore, since the radio wave absorber of the present invention has a mat shape as a whole and has a flat surface, it may be easily visible when the indoor space is used in a room. In particular, it is suitable for installation in a room such as an office building or a general house.

[0020] If inorganic fiber is used as a constituent material, it has excellent fire resistance and can be safely disposed in a living space such as an office building or a general house.

[0021] A conductive material (conductive paint) is attached to a part of the fiber assembly rather than a conventional mat-like fiber assembly attached with a conductive material (conductive paint) to form a radio wave absorber. Therefore, the amount of adhesion can be reduced, the weight can be reduced, and the cost can be reduced. Note that the wrinkle portion to which the conductive material (conductive paint) is not attached is maintained without losing the original heat insulating performance and sound absorbing performance of the fiber assembly.

Brief Description of Drawings

FIG. 1 is a perspective view showing a first embodiment of a radio wave absorber according to the present invention.

FIG. 2 is a longitudinal side view. [FIG. 3] FIG. 3 is a vertical side view for explaining the characteristics depending on the distance between adjacent radio wave absorbers.

[FIG. 4] FIG. 4 is a longitudinal side view for explaining the characteristics of the coupling portion on the enlarged end side of the radio wave absorbers.

FIG. 5 is a longitudinal sectional side view showing a second embodiment.

FIG. 6 is a longitudinal side view showing a third embodiment.

FIG. 7 is a longitudinal side view showing a first modification of the first to third embodiments.

FIG. 8 is a longitudinal sectional side view showing a second modification of the first to third embodiments.

FIG. 9 is a longitudinal side view showing a third modification of the first to third embodiments.

FIG. 10 is a longitudinal side view showing a fourth embodiment.

FIG. 11 is an explanatory diagram of a first embodiment of a method for manufacturing a radio wave absorber according to the present invention.

FIG. 12 is an explanatory diagram of a second embodiment of the manufacturing method.

FIG. 13 is an explanatory diagram of a third embodiment of the manufacturing method.

FIG. 14 is an explanatory diagram of a fourth embodiment of the manufacturing method.

FIG. 15 is an explanatory diagram of a fifth embodiment of the manufacturing method.

FIG. 16 is a frequency characteristic diagram.

FIG. 17 is a frequency characteristic diagram.

FIG. 18 is a frequency characteristic diagram.

Explanation of symbols

1 Fiber assembly

la one side

lb other side

2 Radio wave absorber

3 Conductive material

4 laminated blocks

4a One end

4b The other end 6 Conductive liquid (conductive paint)

7 cylinders

8 Discharge port

9 Piston

10 containers

11 Discharge port

12 Suction cylinder

15 Syringe

16 Injection needle

17 Cylinder

18 piston

20 Upper plate (first plate)

21 Discharge hole

22 Lower plate (second plate)

23 Suction hole

A Stacking direction

F fiber

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.

In the first embodiment shown in FIGS. 1 and 2, FIG. 1 is a perspective view of a radio wave absorber according to the present embodiment, and FIG. 2 is a longitudinal side view thereof.

[0026] The radio wave absorber according to the present embodiment includes a mat-like fiber assembly 1 formed by tangling a large number of fibers F, and the fiber assembly 1 has a conductive material 3 such as carbon attached to the fibers F. It has many radio wave absorbers 2. What is necessary is just to apply the well-known thing of an organic fiber and an inorganic fiber with a fiber, but when using it indoors, the inorganic fiber which has a nonflammability is suitable.

[0027] Each radio wave absorber 2 is formed in an enlarged cross section from one side la side to the other side lb side of the fiber assembly 1, and specifically, each radio wave absorber 2 is formed in a conical shape. ing. Paraphrasing In this case, as shown in FIG. 2, the longitudinal cross-sectional shape of the radio wave absorber 2 is formed in a triangle that extends in a tapered shape toward the one side la side force and the other side lb side of the fiber assembly 1.

That is, the fiber assembly 1 has a radio wave absorber 2 to which the conductive material 3 is attached and a non-conductive portion 5 to which the conductive material 3 is not attached, and the reduced end portion 13 of the radio wave absorber 2. Is disposed on the one surface 1a side of the fiber assembly 1, and the enlarged end portion 14 of the radio wave absorber 2 is disposed on the other surface lb side of the fiber assembly 1 (see FIG. 2).

[0029] For the fiber assembly 1, for example, non-combustible glass wool or rock wool is preferably used.

[0030] It is preferable that the pitch Y when arranging the radio wave absorber 2 is as small as possible. In addition, the distance X (see Fig. 3) between adjacent radio wave absorbers 2 and 2 can be made to transmit radio waves closer to this distance X force ^. Transmission attenuation characteristics are improved.

In addition, as shown in FIG. 4, the other side lb force is directed to one side la so that the radio wave absorbers 2 are connected to each other on the other side lb side. The conductive material 3 may be adhered to the fiber F at the site. In this case, by adjusting the depth Z to which the conductive material 3 is attached, the transmission attenuation amount of the radio wave absorber can be adjusted, and the broadband wave of the radio wave to be absorbed can be achieved.

FIG. 5 is a longitudinal side view showing a second embodiment of the present invention.

[0033] A large number of radio wave absorbers 2 included in the fiber assembly 1 are formed in a three-dimensional frustoconical shape formed by a remaining portion obtained by cutting off the head (tip detail) of the cone along a plane parallel to the bottom surface. It is.

That is, as shown in FIG. 5, each radio wave absorber 2 is formed in a trapezoidal shape in a longitudinal section that expands to one side la side force other side 1 b side of the fiber assembly 1.

[0035] Further, the longitudinal cross-sectional shape of each radio wave absorber 2 is as shown in FIG. 6 except for the case where it is formed so as to expand in a tapered shape (straight shape) as shown in FIGS. The one side 1 a side force of the fiber assembly 1 is formed so as to expand in a curved shape toward the other side lb side, and this may be used as the third embodiment of the present invention. Also, in FIG. 6, each wave absorbing portion 2 has one surface 1 a side force on the fiber assembly 1 and the other surface lb side increasing rate (in the wave absorbing portion 2, the reduced end 13 (Increase in cross-sectional area per unit vertical length) from the side toward the enlarged end 14 side.

In the above description, each radio wave absorber 2 is formed over the entire thickness of the fiber assembly 1 from the one side la of the fiber assembly 1 to the other surface lb! However, it may be formed only in a partial region in the thickness direction of the fiber assembly 1. That is, for example, as in Modification 1 shown in FIG. 7, the enlarged end portion 14 faces the other surface lb, and the reduced end portion 13 reaches only a position halfway toward the other surface lb force one surface la. It may be in a state that is not. In this case, if the width dimension B of the enlarged end portion 14 of each radio wave absorber 2 is constant, the radio wave absorption performance depends on the height dimension A from the end surface of the enlarged end portion 14 to the reduced end portion 13. It will be fixed.

[0037] In the above description, the radio wave absorber 2 is composed of the contour portion of the radio wave absorber 2 and the inner side portion of the contour, but as in Modification 2 illustrated in FIG. The inner part of the contour including the end face portion of the enlarged end portion 14 is left as the non-conductive portion 5 with the conductive material 3 attached, and only on the contour portion of the side peripheral surface excluding the end face portion of the enlarged end portion 14. The conductive material 3 may be attached to form the cone-shaped radio wave absorber 2 only by the contour portion.

[0038] Furthermore, in the above description, the vertical cross-sectional shape of the radio wave absorber 2 on the side of the reduced end 13 is a protrusion, but for example, as in Modification 3 shown in Fig. 9, the radio wave absorber 2 The vertical cross-sectional shape of the reduced end portion 13 may be round and smooth.

In FIG. 3 to FIG. 9, the same reference numerals as those in FIG. 2 are the same as those in FIG.

FIG. 10 is a longitudinal side view showing the fourth embodiment of the present invention.

[0041] The radio wave absorber shown in FIG. 10 has two mat-like fiber assemblies 1 formed by entwining many fibers F, and a laminated block 4 in which these two fiber assemblies 1, 1 are laminated. I have.

[0042] The laminated block 4 has a number of radio wave absorbers 2 formed by adhering the conductive material 3 to the fibers F of the fiber aggregates 1 and 1, each radio wave absorber 2 being a fiber aggregate. The force on the one end face 4a side of the laminated block 4 perpendicular to the lamination direction of the body 1 is also formed in an enlarged cross section toward the other end face 4b.

[0043] Each radio wave absorber 2 has a conical shape (as a whole), and a reduced end portion 13 is arranged on one end surface 4a side of the laminated block 4, and an enlarged end portion 14 is on the other end surface 4b side of the laminated block 4 Is placed in The

Further, the laminated block 4 has a non-conductive portion 5 without the conductive material 3 attached thereto.

More specifically, the two fiber assemblies 1 and 1 are joined (adhered) with an adhesive, and one (the upper side in FIG. 5) fiber assembly 1 has a conductive material 3 on the fiber F. There are many conical conductive parts 2a formed by adhering, and the other (lower) fiber assembly 1 is a truncated conical conductive part 2b formed by adhering conductive material 3 to the fiber F. Have many.

[0046] Then, by joining the bottom surface of the conical conductive portion 2a and the tip of the truncated conical conductive portion 2b so as to coincide with each other, a larger conical wave absorbing portion 2 is obtained. Is forming.

Further, in FIG. 10, each radio wave absorber 2 has a force formed in a vertical cross-sectional triangle, a vertical cross-section trapezoidal shape, or one end surface 4a side force is also curved toward the other end surface 4b side. It may be configured to expand.

[0048] In the above example, each radio wave absorber 2 is provided over the entire thickness of the fiber assembly 1 from one side la to the other side lb of the fiber assembly 1, as shown in FIG. Thus, for example, the enlarged end portion 14 may be in contact with the other surface lb of the fiber assembly 1, while the reduced end portion 13 may have a shape that does not reach the entire surface la. Even in this case, if the width B of the enlarged end portion 14 is substantially constant, the radio wave absorption performance of the radio wave absorber is determined according to the dimension A of the radio wave absorber 2 in the thickness direction of the fiber assembly.

[0049] Alternatively, three or more fiber assemblies 1 may be laminated to form the laminated block 4.

[0050] Next, a first embodiment of a method for manufacturing a radio wave absorber according to the present invention will be described.

[0051] In FIG. 11, a mat-like fiber assembly 1 formed in advance with a large number of fibers F is prepared, and the fiber assembly 1 is placed on a mounting table (not shown) and fixed with a jig or the like. . Further, a conductive liquid 6 in which a conductive material 3 such as carbon and a solvent (for example, hydrogen alcohol) are mixed is placed in a cylinder 7 having a discharge port 8 at the tip. That is, the conductive liquid 6 is a liquid containing the conductive material 3. Then, the discharge port 8 of the cylinder 7 is brought into contact with the upper surface (one surface) 1 a of the fiber assembly 1, and the conductive liquid 6 is pushed out from the discharge port 8 by the piston 9. The conductive liquid 6 pushed out from the discharge port 8 permeates so as to spread from the upper surface la side of the fiber assembly 1 toward the lower surface (other surface) lb side. [0052] The discharge permeation step of the conductive liquid 6 is repeated at a number of predetermined sites of the fiber assembly 1, and then the conductive liquid 6 is dried to form a large number of radio wave absorbers 2 (FIGS. 2 to 5). reference). In this way, the radio wave absorber of this embodiment is completed. That is, in the present embodiment, the conductive material 3 in the conductive liquid 6 is cured and adhered to the fibers F when the conductive liquid 6 is dried.

[0053] Alternatively, a large number of cylinders 7, pistons 9 and the like may be prepared, and the discharge permeation step of the conductive liquid 6 performed at a large number of predetermined portions of the fiber assembly 1 may be performed simultaneously.

FIG. 12 is an explanatory diagram of the second embodiment of the method for manufacturing a radio wave absorber according to the present invention. In this case, the fiber assembly 1 produced in advance is not shown in the figure. Fix with a tool, etc., and put the conductive liquid 6 into the container 10 with the discharge port 11 formed in the bottom. The discharge port 11 is provided in an openable / closable manner so that the conductive liquid 6 placed in the container 10 does not leak carelessly.

[0055] The discharge port 11 of the container 10 is brought into contact with the upper surface (one surface) la of the fiber assembly 1, and the suction cylinder portion 12 of the suction machine (not shown) is provided on the lower surface (other surface) lb side of the fiber assembly 1. Make contact. Then, the suction machine is operated, and the conductive liquid 6 is evacuated and discharged from the discharge port 11. The conductive liquid 6 discharged from the discharge port 11 permeates as if it is expanded from the upper surface la side of the fiber assembly 1 toward the lower surface (other surface) lb side.

[0056] The discharge permeation step of the conductive liquid 6 is repeated at a large number of predetermined portions of the fiber assembly 1, and then the conductive liquid 6 is cured to form a large number of radio wave absorbers 2. In this way, the radio wave absorber of the present embodiment is completed.

[0057] In addition, a large number of containers 10 and suction cylinders 12 having discharge ports 11 are prepared, and the discharge permeation step of the conductive liquid 6 performed at a number of predetermined portions of the fiber assembly 1 is performed simultaneously. It's okay. Furthermore, it is also possible to form a large number of discharge ports 11 in the container 10 and discharge at a plurality of locations at the same time.

[0058] FIGS. 13A to 13C are explanatory views of a third embodiment of the method for manufacturing a radio wave absorber according to the present invention. First, as shown in FIG. The fiber assembly 1 prepared in advance is fixed with a jig (not shown) and the like, and the conductive liquid 6 is put into the cylinder part 17 of the syringe 15 having the injection needle 16, the cylinder part 17, and the piston 18. Next, as shown in FIG. 13 (b), the tip force of the injection needle 16 is pushed into the piston from the upper surface (one surface) la of the fiber assembly 1 while pushing the tip of the injection needle 16 into the piston. Extrude at 18. Then, as shown in FIG. 13 (c), the conductive liquid 6 is permeated so as to spread from the upper surface la side of the fiber assembly 1 toward the lower surface (other surface) lb side.

[0060] Specifically, for example, when the pushing speed of the injection needle 16 is set to be constant, the tip of the injection needle 16 is positioned on the upper side la of the fiber assembly 1. As it is inserted (entered) from the bottom to the bottom lb side, the pressure on the piston 18 should be increased, that is, the amount of discharge of the conductive liquid 6 should be increased.

[0061] Further, when the pressing force of the piston 18 (discharge amount of the conductive liquid 6) is constant, injection is performed as the tip of the injection needle 16 is inserted from the upper surface la side to the lower surface lb side of the fiber assembly 1. Let the needle 16 penetrate at a slower speed.

[0062] The discharge permeation step of the conductive liquid 6 is repeated at a number of predetermined sites of the fiber assembly 1.

Thereafter, the conductive liquid 6 is cured to form a large number of radio wave absorbers 2 (see FIGS. 2 to 5). In this way, the radio wave absorber of this embodiment is completed.

[0063] Figs. 14 (a) to 14 (c) are explanatory views of a fourth embodiment of the method for manufacturing a radio wave absorber according to the present invention. First, a fiber assembly 1 prepared in advance is not shown in the figure. The conductive liquid 6 is put into the cylinder part 17 of the syringe 15 having the injection needle 16, the cylinder part 17, and the piston 18.

Then, as shown in FIG. 14 (a), the tip of the injection needle 16 is pushed into the inside from the upper surface (one surface) la of the fiber assembly 1, and the tip of the injection needle 16 is pushed to the lower surface of the fiber assembly 1. (Other side) Place inside lb.

In FIG. 14 (b), the conductive liquid 6 is pushed out by the piston 18 with the tip force of the injection needle 16 while the tip of the injection needle 16 is pulled out of the fiber assembly 1. Then, as shown in FIG. 14 (c), the conductive liquid 6 is permeated so as to contract by force toward the lower surface lb side force upper surface la side of the fiber assembly 1.

[0066] Specifically, for example, when the drawing speed of the injection needle 16 is set constant, the tip of the injection needle 16 is on the lower surface lb side of the fiber assembly 1. As it is pulled out (retracted) from the upper surface la, the pressure of the piston 18 is weakened, that is, the amount of discharge of the conductive liquid 6 should be reduced and penetrated! [0067] When the pressing force of the piston 18 (discharge amount of the conductive liquid 6) is constant, injection is performed as the tip of the injection needle 16 is pulled out from the lower surface lb side to the upper surface la side of the fiber assembly 1. Soak up the needle 16 at a faster speed.

[0068] The discharge permeation step of the conductive liquid 6 is repeated at a number of predetermined portions of the fiber assembly 1, and then the conductive liquid 6 is cured to form a large number of radio wave absorbers 2 (FIGS. 2 to 5). reference). In this way, the radio wave absorber of this embodiment is completed.

[0069] Further, in the third embodiment and the fourth embodiment, a large number of syringes 15 are arranged, and the conductive liquid 6 performed at a plurality of predetermined sites of the fiber assembly 1 is described above. The discharge permeation process may be performed simultaneously.

FIG. 15 is an explanatory diagram of the fifth embodiment of the method for manufacturing a radio wave absorber according to the present invention. Here, an upper plate 20 having a large number of discharge holes 21 and a lower plate 22 having a large number of suction holes 23 each having a smaller hole size than the discharge holes 21 are used. The discharge holes 21 on the upper plate 20 are arranged with a predetermined arrangement pattern, and the suction holes 23 on the lower plate 22 are arranged with the same arrangement pattern (same arrangement pitch) as the discharge holes 21.

First, the fiber assembly 1 prepared in advance is sandwiched between the upper plate 20 and the lower plate 22.

At this time, the upper plate 20 and the lower plate 22 are arranged so that the discharge holes 21 of the upper plate 20 and the suction holes 23 of the lower plate 22 face each other in the thickness direction of the fiber assembly 1. Then, the upper plate 20 is fixed to the upper side with a jig (not shown) or the like, and then the conductive liquid 6 is stored on the upper plate 20.

In this state, all the suction holes 23 of the lower plate 22 are evacuated. As a result, the conductive liquid 6 on the upper plate 20 is discharged from the discharge holes 21 and permeates from the upper plate 20 side of the fiber assembly 1 toward the lower plate 22 side. At this time, since the suction hole 23 is smaller than the discharge hole 21, the conductive liquid 6 discharged from each discharge hole 21 has a shape in which the cross-sectional shape gradually decreases toward the suction hole 23 corresponding to the discharge hole 21 ( In the example shown in the figure, it penetrates into the inverted triangular shape of the longitudinal section.

[0073] The discharge permeation step of the conductive liquid 6 is repeated at a large number of predetermined portions of the fiber assembly 1, and then the conductive liquid 6 is cured to form a large number of radio wave absorbers 2 (FIG. 2 or FIG. 3). reference) . In this way, the radio wave absorber of this embodiment is completed. The shape of the radio wave absorber 2 is, for example, a conical shape (inverted conical shape) if the discharge holes 21 and the suction holes 23 are circular, and a quadrangular pyramid shape (inverted quadrilateral) if the shape is square. Depending on the shape and size of the discharge hole 21 and the suction hole 23, it can be formed in various cone shapes.

[0074] The fiber assembly 1 includes, for example, a product obtained by compressing glass wool having a thickness of 40 to 50 mm to a thickness of about 30 mm. In addition, a small pilot hole may be formed at a position corresponding to the suction hole 23 of the lower plate 22 in the fiber assembly 1 to control the shape of the radio wave absorber 2. On the other hand, if the suction hole 23 of the lower plate 22 is too small, when the conductive liquid 6 escapes to the lower surface side of the fiber assembly 1, it tends to accumulate on the lower plate 22 and easily contaminate the radio wave absorption surface. Somewhat larger, better, because it will reduce the absorption characteristics.

[0075] A method of using the radio wave absorber according to the present embodiment will be described.

[0076] The radio wave absorber of the present embodiment is arranged so that the reduced end 13 of the radio wave absorber 2 faces the radio wave incident direction. For example, when it is desired to absorb a radio wave that also generates an antenna force, the reduced end portion 13 of the radio wave absorber 2 is disposed toward the antenna side.

[0077] The radio wave absorber of the present embodiment is preferably used in a living space where a mobile phone, a wireless LAN, an IP phone, or the like is used and radio waves are mixed (interference). Indoor walls and ceilings (such as office buildings and general homes) where wireless LAN is installed. Installed on the floor to form a radio wave absorbing wall to prevent radio interference, or this radio wave absorber is attached to the board. Used for internal partitions.

FIGS. 16 to 18 show the radio wave return loss (radio wave absorption) when the linearly polarized wave is vertically incident on the radio wave absorber of the present embodiment manufactured under the following conditions on the vertical axis. FIG. 4 is a frequency characteristic diagram showing the frequency of incident radio waves (linearly polarized waves) on the horizontal axis. Note that the unit of frequency is [GHz] and the unit of return loss is [dB]. In these characteristic diagrams, for example, when the return loss is “−20”, 20 dB of radio waves are absorbed. (It was attenuated).

In the measurement test in FIG. 16, a radio wave absorber (see FIG. 1) in which a large number of radio wave absorbers 2 are formed on a fiber assembly 1 having a glass wool force with a thickness of 25 mm was used.

[0080] In the measurement test in FIG. 17, a fiber assembly 1 having a glass wool force with a thickness of 40 mm 1 In addition, a radio wave absorber (see Fig. 1) with many radio wave absorbers 2 formed was used.

[0081] In the measurement test in Fig. 18, a radio wave absorber (see Fig. 10) in which a large number of radio wave absorbers 2 were formed in a laminated block 4 in which two glass wools having a thickness of 40 mm were laminated.

Note that each of the radio wave absorbers 2 is formed using the conductive liquid 6 having the same component.

[0083] Referring to the characteristic diagram shown in Fig. 16, this radio wave absorber absorbs (decreases) about 15dB for radio waves with a frequency of 1GHz, and absorbs as the frequency of radio waves increases ( The return loss increased, and about 25 dB was absorbed for radio waves with a frequency of 50 GHz. The same measurement test was performed on a fiber assembly 1 having many rock wool forces formed with a number of radio wave absorbers 2 using rock wool with a thickness of 25 mm instead of glass wool with a thickness of 25 mm. As a result, almost the same results as in the case of the glass wool were obtained.

[0084] Referring to the characteristic diagram shown in Fig. 17, about 15dB is absorbed for the 1GHz radio wave, which is not much different from the case of Fig. 16, but about 35dB is absorbed for the 50GHz radio wave. The amount of absorption increased compared to The same measurement test was performed on a fiber assembly 1 having many rock wool forces formed by using rock wool having a thickness of 50 mm instead of glass wool having a thickness of 40 mm, and a plurality of radio wave absorbers 2 formed on the fiber assembly 1 having this rock wool force. As a result, almost the same result as in the case of the glass wool was obtained.

[0085] In the characteristic diagram of Fig. 18, approximately 25 dB is absorbed for 1 GHz radio waves, and the amount of absorption is larger than that of Figs. 16 and 17, and about 35 dB is absorbed for 50 GHz radio waves. The amount of absorption was larger than that in the case of 16, and the absorption amount was almost the same as in the case of FIG. Instead of two glass wools with a thickness of 40 mm, two pieces of rock wool with a thickness of 50 mm were used, and a number of radio wave absorbers 2 were formed on a laminated block 4 made by laminating these rock walls. When the same measurement test was conducted, the same result as in the case of the glass wool was obtained.

[0086] As described above, the radio wave absorber of the present embodiment includes the mat-like fiber assembly 1 formed by entwining a large number of fibers F, and the fiber assembly 1 has radio waves in which the conductive material 3 is attached to the fibers F. Since there are a large number of absorbers 2 and each of the radio wave absorbers 2 is formed in an enlarged cross section from one side la side to the other side lb side of the fiber assembly 1, it can be easily manufactured, and It can absorb radio waves in a wide band. That is, a complicated manufacturing process such as forming a conical filling hole in a plate-like dielectric material or applying a lid as in a conventional radio wave absorber is unnecessary, and a conductive material is added to the fiber assembly 1. By simply attaching 3, it is possible to easily form a large number of radio wave absorbers 2 (such as cones) whose cross-sectional shape is enlarged. Furthermore, in the case of the present embodiment, the overall shape is a mat and has a flat surface, so that it is easy to use the indoor space when arranged indoors. In particular, it is suitable for installation in a room such as an office building or a general house.

[0088] If the inorganic fiber F is used as a constituent material, it has excellent fire resistance and can be safely disposed in a living space such as an office building or a general house.

[0089] Since the conductive material 3 is attached to a part of the fiber assembly 1 rather than the conventional mat-like fiber assembly 1 to which the conductive material 3 is attached, the radio wave absorber 2 is formed. By reducing the amount of adhesion, the weight can be reduced and the cost can be reduced.

[0090] In addition, a laminated block 4 in which a plurality of mat-like fiber assemblies 1 formed by entwining a large number of fibers F is provided, and the laminated block 4 includes a large number of radio wave absorbers 2 with conductive materials 3 attached to the fibers F. Each of the radio wave absorbers 2 is formed in a cross-sectional enlarged shape on the one end surface 4a side of the laminated block 4 orthogonal to the laminating direction A of the fiber assembly 1, so that it can be easily manufactured. Can absorb radio waves in a wide band.

That is, a complicated manufacturing process such as forming a conical filling hole in a plate-like dielectric material or applying a lid as in a conventional wave absorber is not necessary, and the laminated block 4 (fiber assembly By simply attaching the conductive material 3 to 1), it is possible to easily form a large number of radio wave absorbers 2 (such as cones) whose cross-sectional shape is enlarged. Furthermore, since the radio wave absorber of the present invention has a mat-like shape as a whole and has a flat surface, it may have an appearance that makes it easy to use the indoor space when it is installed indoors. In particular, it is suitable for installation in a room such as an office building or a general house.

[0092] If inorganic fiber F is used as a constituent material, it has excellent fire resistance and can be safely disposed in a living space such as an office building or a general house.

[0093] Since the conductive material 3 is attached to a part of the fiber assembly 1 instead of the conventional mat-like fiber assembly 1 to which the conductive material 3 is attached, the radio wave absorber 2 is formed. By reducing the amount of adhesion, the weight can be reduced and the cost can be reduced. [0094] Since the laminated block 4 is formed by laminating a plurality of fiber assemblies 1, for example, when manufacturing a radio wave absorber (laminated block 4) having a large thickness, first, each fiber assembly 1 is manufactured. The conductive block 3 can be adhered to the body 1 by laminating and forming the laminated block 4, and the conductive material 3 can be easily and reliably attached to produce the radio wave absorber 2 having a desired shape. it can. If a plurality of types of fiber assemblies 1 to which the conductive material 3 is attached are prepared in advance, the laminated block 4 having a desired thickness can be easily produced.

[0095] In addition, since the fiber assembly 1 is made of glass wool or rock wool, it has excellent fire resistance and can be safely disposed in a living space such as an office building or a general house.

[0096] In addition, the portion of the fiber assembly 1 other than the radio wave absorbing portion 2 (where the conductive material 3 adheres) is able to exhibit heat insulation and sound absorption. Therefore, it is not necessary to have a two-layer structure in which the radio wave absorption layer and the sound wave absorption layer are separated from the conventional one. A wide indoor space can be secured when it is arranged indoors.

[0097] Further, since it is used as a radio wave absorbing wall for preventing radio interference in a room where a wireless LAN is installed, it is possible to prevent radio waves from being diffused and transmitted in unnecessary directions. As a result, even if a plurality of wireless LAN antennas are installed in a room, radio interference (mutual interference) does not occur, and a wireless LAN system can be constructed.

[0098] In the method of manufacturing the radio wave absorber according to the present embodiment, the discharge port 8 of the cylinder 7 containing the conductive liquid 6 is brought into contact with one surface la of the mat-like fiber assembly 1 formed by tying a plurality of fibers F. Then, the conductive liquid 6 is pushed out from the discharge port 8 by the piston 9, and the conductive liquid 6 is permeated so that the la side force on one side of the fiber assembly 1 spreads toward the other side lb side. The process is repeated or simultaneously performed at a number of predetermined parts of the fiber assembly 1, and then the conductive liquid 6 is cured to form a large number of the radio wave absorbers 2, so that a radio wave capable of absorbing broadband radio waves is obtained. An absorber can be manufactured easily.

That is, a complicated manufacturing process such as forming a conical filling hole in a plate-like dielectric material or applying a lid as in a conventional radio wave absorber is not required, and a conductive liquid is added to the fiber assembly 1. By simply penetrating (coating) 6, it is possible to easily form a large number of radio wave absorbers 2 (such as cones) whose cross-sectional shape is enlarged. Furthermore, the radio wave absorber manufactured by this method Since it is a mat-like body and has a flat surface, it is easy to use the indoor space when placed indoors. In particular, it is suitable for installation in a room such as an office building or a general house.

[0100] If inorganic fiber F is used as a constituent material, it has excellent fire resistance and can be safely disposed in a living space such as an office building or a general house.

[0101] Since the conductive liquid 6 is applied to a part of the fiber assembly 1 instead of the conventional mat-like fiber assembly 1 coated with the conductive liquid 6, the radio wave absorber 2 is formed. The amount applied can be reduced, the weight can be reduced, and the cost can be reduced.

[0102] Further, the discharge port 11 provided in the container 10 containing the conductive liquid 6 is brought into contact with one surface la of the mat-like fiber assembly 1 formed by entwining a large number of fibers F, and the other of the fiber assembly 1 Suction Cylinder 12 is brought into contact with the surface lb side, the conductive liquid 6 is evacuated and discharged from the discharge port 11, and the conductive liquid 6 spreads on one side of the fiber assembly 1 as the la side forces toward the other side lb. The conductive liquid 6 is discharged and penetrated repeatedly or simultaneously at a plurality of predetermined sites of the fiber assembly 1, and then the conductive liquid 6 is cured to form a large number of radio wave absorbers 2. A radio wave absorber capable of absorbing radio waves can be easily manufactured.

That is, a complicated manufacturing process for forming a conical filling hole in a plate-like dielectric material or applying a lid as in a conventional radio wave absorber is not required, and a conductive liquid is added to the fiber assembly 1. By simply penetrating (coating) 6, it is possible to easily form a large number of radio wave absorbers 2 (such as cones) whose cross-sectional shape is enlarged. Furthermore, since the radio wave absorber manufactured by this method is entirely mat-like and has a flat surface, it may be easily visible when the indoor space is used. In particular, it is suitable for installation in a room such as an office building or a general house.

[0104] If the inorganic fiber F is used as a constituent material, it has excellent fire resistance and can be safely disposed in a living space such as an office building or a general house.

[0105] The electromagnetic wave absorbing portion 2 is formed by applying the conductive liquid 6 to a part of the fiber assembly 1 instead of the conventional mat-like fiber assembly 1 coated with the conductive liquid 6. The amount applied can be reduced, the weight can be reduced, and the cost can be reduced.

[0106] Further, in the cylinder part 17 of the syringe 15 having the injection needle 16, the cylinder part 17 and the piston 18, Insert the conductive liquid 6 and push the tip of the injection needle 16 into the piston 18 while pushing the tip of the injection needle 16 inward from one side la of the mat-like fiber assembly 1 formed by tying many fibers F around the tip of the injection needle 16 Then, the conductive liquid 6 is permeated so that the la side force of the one side of the fiber assembly 1 is expanded toward the other side lb side, and the discharge permeation process of the conductive liquid 6 is performed in a number of predetermined portions of the fiber assembly 1. Since the conductive liquid 6 is cured and a large number of the radio wave absorbers 2 are formed, the radio wave absorber capable of absorbing broadband radio waves can be easily manufactured.

That is, a complicated manufacturing process for forming a conical filling hole in a plate-like dielectric material or applying a lid as in a conventional radio wave absorber is unnecessary, and a conductive liquid is added to the fiber assembly 1. By simply penetrating (coating) 6, it is possible to easily form a large number of radio wave absorbers 2 (such as cones) whose cross-sectional shape is enlarged. Furthermore, since the radio wave absorber manufactured by this method is entirely mat-like and has a flat surface, it may be easily visible when the indoor space is used. In particular, it is suitable for installation in a room such as an office building or a general house.

[0108] If the inorganic fiber F is used as a constituent material, it has excellent fire resistance and can be safely disposed in a living space such as an office building or a general house.

[0109] The electromagnetic wave absorbing portion 2 is formed by applying the conductive liquid 6 to a part of the fiber assembly 1 instead of the conventional mat-like fiber assembly 1 coated with the conductive liquid 6. The amount applied can be reduced, the weight can be reduced, and the cost can be reduced.

[0110] Furthermore, by adjusting the pushing speed of the injection needle 16 (to the fiber assembly 1) and the pressing force of the piston 18 (discharge amount of the conductive liquid 6), the radio wave absorber 2 can be freely shaped into a desired shape. Therefore, it is possible to easily manufacture a radio wave absorber corresponding to the frequency range of the radio wave to be absorbed or a radio wave absorber having desired radio wave absorption characteristics.

[0111] Further, a mat-like fiber formed by putting the conductive liquid 6 into the cylinder part 17 of the syringe 15 having the injection needle 16, the cylinder part 17 and the piston 18, and tying a plurality of fibers F around the tip of the injection needle 16. Push one side la of the assembly 1 into the inside, place the tip of the injection needle 16 in the vicinity of the other side lb of the fiber assembly 1, and pull the injection needle 16 from the fiber assembly 1 while pulling the tip of the injection needle 16 As for the force, the conductive liquid 6 is pushed out by the piston 18, and the conductive liquid 6 is applied from the other surface lb side of the fiber assembly 1. One side of the fiber assembly 1 is impregnated so as to shrink, and the discharge and penetration process of the conductive liquid 6 is repeated or simultaneously performed at a plurality of predetermined portions of the fiber assembly 1, and then the conductive liquid 6 is cured to absorb the radio wave absorber 2 Therefore, it is possible to easily manufacture a radio wave absorber capable of absorbing broadband radio waves.

[0112] That is, a complicated manufacturing process such as forming a conical filling hole in a plate-like dielectric material or applying a lid as in a conventional radio wave absorber is not necessary, and a conductive liquid is added to the fiber assembly 1. By simply penetrating (coating) 6, it is possible to easily form a large number of radio wave absorbers 2 (such as cones) whose cross-sectional shape is enlarged. Furthermore, since the radio wave absorber manufactured by this method is entirely mat-like and has a flat surface, it may be easily visible when the indoor space is used. In particular, it is suitable for installation in a room such as an office building or a general house.

[0113] If the inorganic fiber F is used as a constituent material, it has excellent fire resistance and can be safely disposed in a living space such as an office building or a general house.

[0114] The electromagnetic wave absorbing portion 2 is formed by applying the conductive liquid 6 to a part of the fiber assembly 1 instead of the conventional mat-like fiber assembly 1 coated with the conductive liquid 6. The amount applied can be reduced, the weight can be reduced, and the cost can be reduced.

[0115] Further, by adjusting the pulling speed of the injection needle 16 (from the fiber assembly 1) and the pressing force of the piston 18 (discharge amount of the conductive liquid 6), the radio wave absorber 2 can be shaped into a desired shape. It can be freely formed, and a radio wave absorber corresponding to the frequency range of the radio wave to be absorbed and a radio wave absorber having desired radio wave absorption characteristics can be easily manufactured.

[0116] Further, the upper plate 20 having a large number of discharge holes 21 and a large number of suction holes 23 each having a smaller diameter than the discharge holes 21 of the upper plate 20 are provided. A mat-like fiber assembly 1 formed by tying a large number of fibers F is sandwiched between the upper plate 20 and the lower plate 22 disposed so as to correspond to the numerous discharge holes 21 of the upper plate 20 respectively. The conductive liquid 6 is stored in the discharge holes 21 of the upper plate 20, and the conductive liquid 6 is sucked from the suction holes 23 of the lower plate 22 and discharged from the discharge holes 21, thereby supplying the conductive liquid 6 to the fiber assembly. In order for each pair of discharge hole 21 and suction hole 23 corresponding to the discharge permeation work to permeate so as to shrink from the surface of the upper plate 20 side to the surface of the lower plate 22 side by side. Or it can carry out simultaneously and can harden the electrically conductive liquid 6 after that, and can form the some electromagnetic wave absorption part 2. FIG.

[0118] If the inorganic fiber F is used as a constituent material, it has excellent fire resistance and can be safely disposed in a living space such as an office building or a general house.

[0119] The electromagnetic wave absorbing portion 2 is formed by applying the conductive liquid 6 to a part of the fiber assembly 1 instead of the conventional mat-like fiber assembly 1 coated with the conductive liquid 6. The amount applied can be reduced, the weight can be reduced, and the cost can be reduced.

[0120] Further, the size of the discharge hole 21 of the upper plate 20 and the suction hole 23 of the lower plate 22, the depth of the conductive liquid 6 accumulated on the upper plate 20, and the suction force to the suction hole 23 of the lower plate 22 By adjusting the, the radio wave absorber 2 can be freely formed into a desired shape and absorbed! / A radio wave absorber corresponding to the frequency range of the radio wave, or a radio wave having a desired radio wave absorption characteristic An absorber can be manufactured easily.

Claims

The scope of the claims

[1] A mat-like fiber assembly formed by entwining a plurality of fibers,

Each of the fiber assemblies includes a plurality of radio wave absorbers formed in an enlarged cross-section from one side of the fiber assembly to the other side, and a conductive material attached to the fibers! An electromagnetic wave absorber characterized by

[2] A laminated block obtained by laminating a plurality of mat-like fiber assemblies formed by entwining a plurality of fibers, and traversing from the one surface side of the laminated block to the other surface side in the lamination direction of the fiber assemblies in the laminated block, respectively. A radio wave absorber comprising a plurality of radio wave absorbers formed in an enlarged surface and having a conductive material attached to the fibers.

[3] The electromagnetic wave absorber according to claim 1 or 2, wherein the fiber assembly has a glass wool or rock wool force.

[4] Claims used for radio wave absorption walls to prevent radio interference in a room where a wireless LAN is installed

The electromagnetic wave absorber according to 1, 2 or 3.

[5] The discharge port of the cylinder containing the conductive paint is brought into contact with one surface of a mat-like fiber assembly formed by tangling a plurality of fibers,

The discharge roller The conductive paint is pushed out by a piston, and the conductive paint is infiltrated so as to spread on one side of the fiber assembly toward the other side,

Repeating or simultaneously performing the discharge penetration step of the conductive paint at a plurality of predetermined portions of the fiber assembly,

Thereafter, the conductive paint is cured to form a plurality of radio wave absorbers.

[6] A discharge port provided in a container containing a conductive paint is brought into contact with one surface of a mat-like fiber assembly formed by entwining a plurality of fibers,

A suction arch I is brought into contact with the other surface side of the fiber assembly, and the conductive paint is evacuated and discharged from the discharge port, and the conductive paint is discharged from one side of the fiber assembly to the other side. So that it spreads toward

Repeating or simultaneously performing the discharge penetration step of the conductive paint at a plurality of predetermined portions of the fiber assembly, Thereafter, the conductive paint is cured to form a plurality of radio wave absorbers.

[7] A conductive paint is put into the cylinder portion of a syringe having a syringe needle, a cylinder portion, and a piston, and the tip of the syringe needle is pushed into the inside from one side of a mat-like fiber assembly formed by tangling a plurality of fibers. While pushing the conductive paint from the tip of the injection needle with the piston, the conductive paint penetrates so that the force on one side of the fiber assembly also spreads toward the other side,

[8] A conductive paint is put into the cylinder portion of a syringe having a syringe needle, a cylinder portion, and a piston, and the tip of the syringe needle is pushed into the inside from one surface of a mat-like fiber assembly formed by tangling a plurality of fibers. Then, the tip of the injection needle is disposed in the vicinity of the other surface of the fiber assembly, and the injection needle is pulled out from the fiber assembly,

Tip force of the injection needle The conductive paint is pushed out by the piston, and the conductive paint is infiltrated so as to contract by force toward the other side of the fiber assembly.

[9] A first plate having a plurality of discharge holes, and a plurality of suction holes each having a smaller diameter than the discharge holes of the first plate, wherein the plurality of suction holes are respectively provided on the first plate. A mat-like fiber assembly formed by tangling a plurality of fibers between the second plate and the second plate arranged to face the first plate so as to correspond to the plurality of discharge holes,

Conductive paint is stored in each discharge hole of the first plate,

The conductive paint is sucked from the suction holes of the second plate and discharged from the discharge holes, and the conductive paint is applied to the surface force on the first plate side of the fiber assembly. Perform the discharge penetration work to permeate so as to shrink toward the side surface,

Then, a method of manufacturing a radio wave absorber, wherein the conductive paint is cured to form a plurality of radio wave absorbers.