JP2968478B2 - Radio wave absorber and its mounting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block-shaped radio wave absorber made of a foamed resin material such as styrene foam, foamed polyethylene, foamed phenol or foamed urethane used in an anechoic chamber and a method of mounting the same. Field of the Invention The present invention relates to a radio wave absorber that can be securely and firmly attached to a wall, a side wall, and the like, and a method of attaching the same.

[0002]

2. Description of the Related Art Conventionally, a block-shaped radio wave absorber made of a foamed resin material such as foamed styrene, foamed polyethylene, foamed phenol, or foamed urethane has been used on a ceiling or a side wall of an anechoic chamber. It was fixed using an adhesive.

As shown in FIG. 15A, for example, this radio wave absorber has a pyramid-shaped or zigzag-shaped projection (hereinafter referred to as a projection) 12 and a flat surface adhered to a ceiling or a side wall. (Hereinafter referred to as base material)
An adhesive 30 is applied to the bonding surface of the base member 11 and is fixed to the ceiling or the side wall by bonding.

However, the block-shaped radio wave absorber 10 made of a foamed resin material such as foamed styrene, foamed polyethylene, foamed phenol or foamed urethane contains a conductive resin such as carbon black or graphite. The bonding strength between them and the adhesive strength with the adhesive were weak, and it was difficult to firmly attach them to ceilings and side walls.

That is, as shown in FIG. 15B (section AA ′ of FIG. 15A when the radio wave absorber 10 is adhered to a ceiling or a side wall), the conductive powder 10b is contained in the foamed resin material 10a. , The bonding strength between the foamed resin materials 10a was weak, and the bonding strength with the adhesive 30 was weak because the conductive powder 10b was exposed on the bonding surface of the base portion 11.

Therefore, when the radio wave absorber is attached to the ceiling or the side wall 40, the radio wave absorber 10 may come off.

Accordingly, an object of the present invention is to provide a radio wave absorber that can be firmly mounted on a ceiling or a side wall of an anechoic chamber, and a method of mounting the radio wave absorber.

[0008]

According to a first aspect of the present invention, there is provided a radio wave absorber in which a bonding surface is filled with an adhesive in a block-shaped radio wave absorber made of a foamed resin material mixed with a conductive powder. Characterized in that the shape of the groove or the recess is such that the shape of the groove or the recess engages with the filled and hardened adhesive.

According to a second aspect of the present invention, in the radio wave absorber of the first aspect, the groove or the concave portion is formed by a member embedded at the time of molding. .

According to a third aspect of the present invention, there is provided the radio wave absorber according to the first aspect, wherein a peripheral portion of the groove or the concave portion is depressed inward from the bonding surface. is there.

According to a fourth aspect of the present invention, there is provided a radio wave absorber comprising a block-shaped radio wave absorber made of a foamed resin material mixed with a conductive powder, wherein an adhesive is formed inside the radio wave absorber so as to mesh with the radio wave absorber. An auxiliary member is embedded, and a part of the adhesion auxiliary member is exposed on the bonding surface side of the radio wave absorber.

[0012] According to a fifth aspect of the present invention, there is provided a method of mounting a radio wave absorber.
In a method of mounting a block-shaped radio wave absorber made of a foamed resin material mixed with a conductive powder and having a groove or a concave portion on an adhesive surface, a through hole is provided in a plate material to which the radio wave absorber is attached, And injecting an adhesive into the groove or the concave portion through the groove.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1 or FIG. 2, a radio wave absorber according to the present invention has a protruding portion (a portion having a pyramid-shaped or zigzag-shaped projection) 12 and a base material (a ceiling, a side wall, or the like). A groove portion 21 or a concave portion 22 is provided on the bonding surface of the base portion 11, and the groove portion 21 or the concave portion 22 is filled with an adhesive and bonded. The adhesive strength with the ceiling and side walls of the anechoic chamber is improved.

The direction in which the groove 21 is provided is shown in FIG.
As shown in (b), the direction may be (a) the longitudinal direction, (b) the lateral direction, or any other direction (oblique direction). Further, the number and positions of the concave portions 22 shown in FIG. 2 are not particularly limited.

Also, styrene foam, foamed polyethylene,
The radio wave absorber made of a foamed resin material such as foamed phenol or foamed urethane is produced, for example, as follows.

First, a coating agent is prepared by mixing a conductive powder such as carbon black or graphite into an adhesive, and then the coating agent is added to styrene foam which has been primarily foamed, stirred, and then put into a mold. Then, it is formed by secondary foaming.

In the case of urethane foam, it is produced by foaming without adding a coating agent, molding, dipping in a coating agent, and forcibly drying.

In the case of foamed polyethylene, a conductive powder such as carbon black or graphite is kneaded in advance with a polyethylene resin, a foaming agent is added to the kneaded material, and then the mixture is placed in a mold, foamed, and molded. .

The groove on the bonding surface of the base member may be formed by molding, or may be formed by cutting after molding. Further, a resin material having a desired groove or concave portion may be embedded at the time of mold molding.

Next, the shape of the groove or the recess will be described in detail. In the following description of the groove or the concave portion, the BB ′ cross section of the groove 21 shown in FIGS.
The shape of the CC ′ section or the DD ′ section and / or the EE ′ section of the recess 22 shown in FIG. 2 will be described.

FIG. 3 shows a case where the radio wave absorber according to the present invention is mounted on a ceiling or a side wall of an anechoic chamber. As shown in the figure, in the radio wave absorber according to the present invention, the adhesive 3 is attached to the groove or the recess provided in the base 11.
0, and the adhesive 30 adheres the radio wave absorber to a ferrite plate 40 generally used as a material of a ceiling or a side wall of the radio wave anechoic chamber. In some cases, it is directly bonded to a metal plate for shielding.

With respect to the shape of the groove or the concave portion of the radio wave absorber according to the present invention, for example, various shapes as shown in FIGS. 4 to 9 can be considered. The groove or recess 20 shown in these figures has a cross-section in the shape of a wedge, a hook, or the like, and when the filled adhesive is hardened, the hardened adhesive and the base 11 of the radio wave absorber are used. It is in a state of meshing. Therefore, even if a force is applied to the solidified adhesive in a direction perpendicular to the adhesive surface of the base member 11, the adhesive cannot be easily pulled out.

In other words, the shape of the groove or the concave portion of the radio wave absorber according to the present invention is such that when a force is applied to the filled and solidified adhesive in a direction perpendicular to the adhesive surface of the base material portion 11,
Any shape that cannot be easily pulled out may be used. Therefore, for example, the groove or the recess may have a cross-sectional shape such as a wedge, an L-shape, or a T-shape, or the recess may be a screw hole formed by cutting.

FIG. 10 shows a case where the groove or recess 20 is formed by embedding an adhesive accommodating member 23 which has been machined in accordance with the shape. As the adhesive accommodating member 23, a resin material or the like processed into a U-shape or an arc shape with a divergent cross section can be used.

Further, as shown in FIG. 11, in order to widen the bonding surface between the adhesive 30 and the ferrite plate 40, a portion depressed inward from the bonding surface of the base portion 11 around the groove or the concave portion ( (Hereinafter referred to as an adhesive surface extension). FIG.
Reference numeral 2 denotes a case where an adhesive surface extension 20a is provided around the groove or the recess 20. This adhesive surface extension 20
“a” is particularly effective when the opening of the groove or the concave portion 20 is narrowed for the purpose of strengthening the engagement between the adhesive and the base material.

As shown in FIG. 13, an auxiliary bonding member 13 having a shape that meshes with the base member 11 is embedded in the base member 11, and the bonding auxiliary member 13 and the ferrite plate 40 are bonded with an adhesive 30. The radio wave absorber may be attached by bonding. In this case, the shape of the adhesion auxiliary member 13 is
A resin material or the like having the same shape as the groove or the concave portion (the same shape as the adhesive filled in the groove or the concave portion) can be used. FIG. 14 shows an example of the adhesion auxiliary member 13. In order to secure a space (adhesive accommodating portion 20 b) for interposing the adhesive between the adhesion auxiliary member 13 and the ferrite plate, the adhesion auxiliary member 13 is provided. The exposed surface of the substrate 13 is sunk inside the adhesive surface of the base member 11.

In the conventional radio wave absorber, an adhesive is applied to the bonding surface of the base member and bonded to the ceiling or side wall of the anechoic chamber. A gap is formed between them (a gap is formed due to the interposition of an adhesive), and this gap sometimes lowers the radio wave absorption characteristics. However, in the radio wave absorber according to the present invention,
Since the adhesive is accommodated in the groove, the concave portion, or the expanded portion of the bonding surface, a gap is not formed between the surface of the ceiling or the side wall and the bonding surface of the base portion, and the radio wave absorption characteristics are not deteriorated.

When the radio wave absorber according to the present invention is mounted on a ceiling, a side wall, or the like, a portion such as a groove, a concave portion, or an expanded portion of an adhesive surface provided in the base may be filled with an adhesive and then bonded. Is temporarily fixed on the ceiling or side wall in advance,
The adhesive may be injected from a through hole provided in a ceiling or a side wall.

When the adhesive is injected into the groove, the recess, or the expanded portion of the bonding surface after the radio wave absorber is temporarily fixed to the ceiling or the side wall as described above, the radio wave absorber is not fixed to the ceiling or the side wall. As a result, better radio wave absorption characteristics can be obtained. Also, the work of attaching the radio wave absorber can be performed more easily.

[0030]

The radio wave absorber according to the present invention can be firmly attached to the ceiling or the side wall of the radio wave anechoic chamber by providing the base or the groove as described above.
In addition, since it can be in close contact with a surface such as a ceiling or a side wall, good radio wave absorption characteristics can be obtained.

When an adhesive is injected into a groove, a concave portion, or an expanded portion of an adhesive surface after the radio wave absorber is temporarily fixed to a ceiling or a side wall, the operation of attaching the radio wave absorber, the ceiling or the side wall, etc. Adhering to the side walls and the like becomes easier.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a radio wave absorber according to the present invention (when a groove is provided).

FIG. 2 is a perspective view showing a radio wave absorber according to the present invention (when a concave portion is provided).

FIG. 3 is a cross-sectional view showing a case where the radio wave absorber according to the present invention is bonded to a ferrite plate.

FIG. 4 is a cross-sectional view showing a groove or a recess provided in a base portion of the radio wave absorber according to the present invention.

FIG. 5 is a cross-sectional view showing a groove or a recess provided in a base portion of the radio wave absorber according to the present invention.

FIG. 6 is a cross-sectional view showing a groove or a recess provided in a base portion of the radio wave absorber according to the present invention.

FIG. 7 is a cross-sectional view showing a groove or a recess provided in a base portion of the radio wave absorber according to the present invention.

FIG. 8 is a cross-sectional view showing a groove or a recess provided in a base portion of the radio wave absorber according to the present invention.

FIG. 9 is a cross-sectional view showing a groove or a recess provided in a base portion of the radio wave absorber according to the present invention.

FIG. 10 is a cross-sectional view showing a groove or a recess provided in a base portion of the radio wave absorber according to the present invention (when an adhesive accommodating member is used).

FIG. 11 is a cross-sectional view showing a case where the radio wave absorber according to the present invention is adhered to a ferrite plate (in the case where an adhesion surface extending portion is provided).

FIG. 12 is a cross-sectional view showing a groove or a concave portion provided in the base portion of the radio wave absorber according to the present invention (in the case where an adhesive surface extending portion is provided).

FIG. 13 is a cross-sectional view showing a case where the radio wave absorber according to the present invention is bonded to a ferrite plate (when a bonding auxiliary member is embedded in a base material).

FIG. 14 is a cross-sectional view showing an adhesion auxiliary member embedded in a base portion of the radio wave absorber according to the present invention.

FIG. 15 is a perspective view showing a conventional radio wave absorber and a cross-sectional view showing an adhesive portion thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Radio wave absorber 10a Foam resin material 10b Conductor powder 11 Base material part 12 Projection part 13 Adhesion auxiliary member 20 Groove or concave part 20a Attachment surface extension part 21 Groove part 22 Recess 23 Adhesive accommodating member 30 Adhesive 40 Ferrite plate

Continuation of the front page (56) References JP-A-2-44800 (JP, A) JP-A 54-169403 (JP, U) JP-A 1-171095 (JP, U) (58) Fields investigated (Int) .Cl. ⁶ , DB name) H05K 9/00 E04B 1/92

Claims (4)

(57) [Claims] 1. A block-shaped radio wave absorber made of a foamed resin material mixed with a conductor powder, wherein the bonding surface has a groove or a concave portion for filling an adhesive, and the shape of the groove or the concave portion. Is a shape that meshes with the filled and hardened adhesive, and the groove or recess is formed by a member embedded during molding. 2. A block-shaped radio wave absorber made of a foamed resin material mixed with a conductive powder, wherein the bonding surface has a groove or a concave portion for filling an adhesive, and the shape of the groove or the concave portion. Is a shape that meshes with the filled and hardened adhesive, and the peripheral portion of the groove or the concave portion is depressed inward from the adhesive surface. 3. A block-shaped radio wave absorber made of a foamed resin material mixed with a conductor powder, wherein an adhesion auxiliary member meshing with the radio wave absorber is embedded inside the radio wave absorber. A radio wave absorber characterized in that a part of the auxiliary member is exposed on the bonding surface side of the radio wave absorber. 4. A method for mounting a block-shaped radio wave absorber made of a foamed resin material mixed with a conductor powder and having a groove or a concave portion on an adhesive surface, wherein a through hole is formed in a plate material to which the radio wave absorber is mounted. Providing an adhesive into the groove or the recess through the through hole.