WO2013013906A1

WO2013013906A1 - Cladding element for providing shielding against electromagnetic radiation

Info

Publication number: WO2013013906A1
Application number: PCT/EP2012/061973
Authority: WO
Inventors: Mauro Maggioni
Original assignee: Lamiflex S.P.A.
Priority date: 2011-07-28
Filing date: 2012-06-21
Publication date: 2013-01-31
Also published as: ITMI20111417A1

Abstract

A cladding element (1, 1a) for providing shielding against electromagnetic radiation. The peculiarity of the invention resides in that it comprises at least one shielding layer (2, 2a) which comprises an electrically conducting fabric (3, 3a) and a resin matrix (4, 4a) which embeds the electrically conducting fabric (3, 3a).

Description

CLADDING ELEMENT FOR PROVIDING SHIELDING AGAINST ELECTROMAGNETIC RADIATION

The present invention relates to a cladding element for providing shielding against electromagnetic radiation.

As is known, adapted shielding is used to protect electronic devices against electromagnetic noise originating from outside or to prevent the outward emission of electromagnetic waves generated by the devices themselves.

The shielding against electromagnetic radiation that is currently used is generally constituted by containers which comprise layers of conducting material such as metallic sheets, metallic nets or metallic foams, which enclose completely an electronic device.

Shielding against electromagnetic radiation is also known which is obtained by covering uniformly with conducting metallic paints the internal surface of the container of the electronic device to be protected against electromagnetic noise.

However, the use of complex electronic devices, in the most disparate sectors, from telecommunications to consumer electronics, from aeronautics- avionics to the military, requires shielding against electromagnetic radiation that can be applied to objects or structures having various shapes, sizes and mechanical properties, and that is capable of adapting to the different technical characteristics of the objects to be clad, and can also ensure high shielding efficiencies.

Conventional types of shielding against electromagnetic radiation are not always able to meet these requirements since the use of metallic conducting materials, such as metallic nets or sheets, in such shielding, generates important increases in terms of weight and therefore prevents their use in sectors such as aeronautics or transportation in general, where the weight factor is fundamentally important.

Another limitation of conventional types of shielding against electromagnetic radiation consists in that they require complicated production processes which are different in each case depending on the shape of the object to be shielded and are therefore expensive.

Moreover, shielding against electromagnetic radiation of the known type, with particular reference to the use of conducting paints, requires continuous maintenance and/or replacement.

The aim of the present invention is to provide a cladding element for providing shielding against electromagnetic radiation that overcomes the limitations of conventional types of shielding and can be manufactured with a method which is simple and quick to provide.

Within this aim, an object of the invention is to provide a cladding element that can adapt without problems to objects that have different shapes and dimensions and is compatible with the mechanical properties of the object to be clad.

Another object of the invention is to provide a cladding element that has a low weight.

A further object of the invention is to provide a cladding element that is capable of shielding efficiently even high electromagnetic wave frequencies.

Another object of the invention is to provide a cladding element that maintains the shielding capacity and mechanical properties durably over time.

Another object of the invention is to provide a cladding element which, even in its more complex shapes, can be easily connected to the ground or to other conducting elements.

A further object of the invention is to provide a cladding element that is capable of giving the greatest assurances of reliability and safety in use.

Another object of the invention is to provide a cladding element that is economically competitive and ensures high shielding efficiency.

This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by a cladding element for providing shielding against electromagnetic radiation, characterized in that it comprises at least one shielding layer which comprises an electrically conducting fabric and a resin matrix which embeds said electrically conducting fabric.

Further characteristics and advantages of the invention will become better apparent from the description of two preferred but not exclusive embodiments of the cladding element for providing shielding against electromagnetic radiation according to the invention, illustrated by way of non-limiting example with the aid of the accompanying drawings, wherein:

Figure 1 is a partially sectional perspective view of the cladding element according to the invention in a first embodiment;

Figures 2 to 6 are schematic sectional sequential views of some of the steps for the manufacture of the cladding element according to the invention shown in Figure 1, taken along a plane which is perpendicular to the planes of arrangement of the layers that compose it;

Figure 7 is a partially sectional perspective view of the cladding element according to the invention in a second embodiment;

Figures 8 to 12 are schematic sectional sequential views of some of the steps for the manufacture of the cladding element according to the invention shown in Figure 7, taken along a plane which is perpendicular to the planes of arrangement of the layers that compose it.

With reference to the figures, the cladding element for providing shielding against electromagnetic radiation according to the invention, generally designated in the two embodiments by the reference numerals 1, la, comprises a shielding layer 2, 2a, which comprises an electrically conducting fabric 3, 3a and a resin matrix 4, 4a which embeds the electrically conducting fabric 3, 3a.

The electrically conducting fabric 3, 3 a is constituted advantageously by a fabric made of a material which is originally not electrically conducting, such as for example polyester, Kevlar, aramid fiber, carbon fiber, glass fiber, which is rendered conducting by metallization of the fabric itself, or of all or some of the fibers that compose it, for example by deposition of metals such as nickel or zinc.

As an alternative, the electrically conducting fabric 3, 3 a is constituted by a fabric which is at least partially composed of fibers made of electrically conducting material, such as for example a polyester fabric combined with metallic wires in the weft or in the warp.

The resin matrix 4, 4a is constituted advantageously by a thermosetting resin, such as for example an epoxy resin, or by a thermoplastic resin.

The cladding element 1, la comprises advantageously also one or more reinforcement layers 5, 5a, 6, 6a, which are coupled to the shielding layer 2, 2a so as to overlap. The reinforcement layers 5, 5a and 6, 6a comprise a layer of fabric 7, 7a, preferably made of carbon fiber or glass, which is impregnated with a resin matrix, such as for example of the type of the resin matrix 4, 4a which embeds the electrically conducting fabric 3, 3a.

The cladding element 1, 1a according to the invention has an exposed region 8, 8a, which is connected electrically to the electrically conducting fabric 3, 3a and is adapted to define an external electrical contact for the electrically conducting fabric 3, 3a of the shielding layer 2, 2a.

In the first embodiment of the cladding element according to the invention, shown in Figure 1 , a layer of electrically conducting paint 9 is applied at the exposed region 8 and is in direct contact with at least one portion of the electrically conducting fabric 3 of the shielding layer 2.

In the second embodiment of the cladding element according to the invention, shown in Figure 7, an electrically conducting contact element 10a is applied at the exposed region 8a and is placed in direct electrical contact with at least one portion of the electrical conducting fabric 3 a of the shielding layer 2a. The contact element 10a is advantageously compressible and permeable to the resin matrix 4a. The contact element 10a is constituted advantageously by the soft portion or female element made of electrically conducting material of a tear strip of the type known commercially by the trademark Velcro or by an electrically conducting felt.

In both Figures 1 and 7, by way of example, the electrical contact is defined along the perimetric edge, which constitutes the exposed region 8, 8a of the cladding element 1, 1a, since the cladding layer 5, 5a has a smaller surface than the underlying shielding layer 2, 2a, and its perimeter is contained entirely within the shielding layer 2, 2a.

The cladding element 1, la has an excellent capacity to shield electromagnetic waves, with shielding values of even more than 80 dB for frequencies between 1 MHz and 6 GHz.

The method for the manufacture of the cladding element 1, la for providing shielding against electromagnetic radiation according to the invention is as follows.

Figures 2 to 6 are schematic sequential views of some of the steps for the manufacture of the cladding element 1 according to the invention as regards the first preferred embodiment, as shown in Figure 1.

With particular reference to Figure 2, the method for the manufacture of the cladding element 1 comprises first of all a step of preparation of the electrically conducting fabric 3 which is impregnated, for example by means of solvent, in the resin matrix 4, obtaining the semifinished shielding layer 2, which can be shaped conveniently according to the shape of the object to be clad. Impregnation occurs for example by passing in an impregnation bath or other known type of method.

Advantageously, additional reinforcement layers 5 and 6 are coupled to the shielding layer 2 and are in turn constituted by fabrics 7 made of various materials, impregnated in the resin matrix which can be the same resin matrix 4, as in the illustrated case, or another resin matrix, also in semifinished conditions, i.e., in conditions in which they can be shaped conveniently.

Figure 2 is a view of the cladding element 1 , as defined initially by the coupling of the shielding layer 2 with the reinforcement layers 5 and 6, wherein the cladding element 1 has an exposed region 8 of the shielding layer 2 that composes it.

Figure 3 is a view of a subsequent step of the method for the production of the cladding element 1, in which a protective element 12, which is permeable to the resin matrix 4 and is constituted advantageously by material of the so-called "peel-ply" type, i.e., a material that can adhere temporarily to a substrate and can be removed subsequently with relative ease, is applied at the exposed region 8 of the shielding layer 2.

Figure 4 is a view of the step of stabilization of the resin matrix 4 respectively on the electrically conducting fabric 3 and on the fabrics that compose the reinforcement layers 5 and 6. The stabilization step comprises a step of forming by heating and compression of the shielding layer 2 and of the reinforcement layers 5 and 6. The forming step occurs conveniently in an autoclave if the cladding element 1 is intended to assume shapes having a complex geometry, or in a hot press, or as an alternative in an oven, using the vacuum bag methods. Compression and heating entail first of all the impregnation of the protective element 12 by the resin matrix 4 that is present at the exposed region 8 of the shielding layer 2 and then the setting by polymerization of the resin matrix 4, which permanently and rigidly embeds the electrically conducting fabric 3 of the shielding layer, the fabrics 7 that compose the reinforcement layers 5 and 6, and the protective element 12.

At the end of the stabilization step, as shown in Figure 5, the protective element 12, now partially impregnated with the set resin matrix 4, is removed. This action entails the separation of the resin matrix 4 from the underlying electrically conducting fabric 3, exposing to the outside portions of the electrically conducting fabric 3. After the removal of the protective element 12, some residues of set resin 11 may generally remain present on the surface of the exposed region 8 of the electrically conducting fabric 3 of the shielding layer 2.

Figure 6 is a view of the last step of the production method of the cladding element, which consists in applying a layer of paint 9 on the exposed region 8 so as to obtain a region of uniform electrical contact despite the presence of the above cited resin residues. The layer of electrically conducting paint 9 defines an external electrical contact which is connected electrically to the electrically conducting fabric 3 of the shielding layer 2.

Some of the steps of the method for the production of the cladding element la according to the second preferred embodiment, as shown in Figure 7, are shown in Figures 8 to 12.

This method differs from the one described earlier substantially in the application of an electrically conducting contact element 10a at the exposed region 8a of the shielding layer 2a, where the contact element 10a, advantageously of the type of Velcro or electrically conducting felt, is in electrical contact with the underlying electrically conducting fabric 3 a.

Figure 8 is a view of the step in which the contact element 10a is arranged at the exposed region 8a of the shielding layer 2a.

Figure 9 is a view of the step in which the protective element 12a is applied at the exposed region 8a and is superimposed on the contact element 10a. The contact element 10a is compressible and permeable to the resin matrix 4a.

Figure 10 is a view of the step of stabilization of the resin matrix 4a, which, in compression and heating conditions, impregnates the protective element 12a and penetrates the contact element 10a, impregnating it.

At the end of the stabilization step, as shown in Figure 11 , the resin matrix 4a has set by polymerization and therefore the contact element 10a is fixed rigidly at its base and is therefore in contact with the electrically conducting fabric 3a of the shielding layer 2a. The protective element 12a is then removed and the excess resin matrix 4a that impregnates the contact element 10a is also removed with it.

Figure 12 illustrates the situation in which, following the steps described above, the contact element 10a is in contact with the electrically conducting fabric 3a of the shielding layer 2a and therefore in the second preferred embodiment, too, an external electrical contact is defined which is connected electrically to the electrically conducting fabric 3 a of the shielding layer 2a.

In practice it has been found that the cladding element for providing shielding against electromagnetic radiation, according to the present mentioned, achieves the intended aim and objects, since it makes it possible to provide versatile shielding for objects having various shapes, dimensions and mechanical properties.

Another advantage of the cladding element according to the invention resides in that it has a low weight.

A further advantage of the cladding element according to the invention resides in that it ensures high electrical conductivity, even in view of the use of various types of fabric that constitute the shielding layer.

Another advantage of the cladding element according to the invention resides in that it ensures shielding against electromagnetic waves even in a high frequency range.

A further advantage of the cladding element according to the invention resides in that it is quick and simple to install, as well as low in cost.

The cladding element thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

All the details may further be replaced with other technically equivalent elements.

In practice, the materials used, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to requirements.

The disclosures in Italian Patent Application No. MI201 1A001417 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A cladding element (1, la) for providing shielding against electromagnetic radiation, characterized in that it comprises at least one shielding layer (2, 2a) which comprises an electrically conducting fabric (3, 3a) and a resin matrix (4, 4a) which embeds said electrically conducting fabric (3, 3a).

2. The element (1, la) according to claim 1, characterized in that said electrically conducting fabric (3, 3a) is constituted by a fabric made of metalized material which is not electrically conducting.

3. The element (1, la) according to claim 1, characterized in that said electrically conducting fabric (3, 3a) is constituted by a fabric composed at least partially of fibers made of electrically conducting material.

4. The element (1 , la) according to one or more of the preceding claims, characterized in that said resin matrix (4, 4a) is constituted by a thermosetting resin.

5. The element (1 , la) according to one or more of the preceding claims, characterized in that said resin matrix (4, 4a) is constituted by a thermoplastic resin.

6. The element (1 , la) according to one or more of the preceding claims, characterized in that it comprises at least one reinforcement layer (5,

5a, 6, 6a) which is coupled so as to be superimposed on said shielding layer (2, 2a).

7. The element (1 , la) according to one or more of the preceding claims, characterized in that said reinforcement layer (5, 5a, 6, 6a) comprises a fabric that is impregnated with a resin matrix (4, 4a).

8. The element (1 , la) according to one or more of the preceding claims, characterized in that it has an exposed region (8, 8a) which is connected electrically to said electrically conducting fabric (3, 3a) and is adapted to define an external electrical contact for said electrically conducting fabric (3, 3a).

9. The element (1) according to one or more of the preceding claims, characterized in that said exposed region (8) is defined by a layer of electrically conducting paint (9) in direct contact with at least one portion of said electrically conducting fabric (3).

10. The element (la) according to one or more of the preceding claims, characterized in that said exposed region (8a) is defined by an electrically conducting contact element (10a) which is arranged in direct contact with at least one portion of said electrically conducting fabric (3 a).

11. The element (la) according to one or more of the preceding claims, characterized in that said contact element (10a) is compressible and permeable to said resin matrix (4a).

12. A method for manufacturing a cladding element (1, la) for providing shielding against electromagnetic radiation, according to one or more of the preceding claims, characterized in that it comprises:

- a step of preparing an electrically conducting fabric (3, 3a);

- a step of impregnating said electrically conducting fabric (3, 3a) with a resin matrix (4, 4a) to obtain a semifinished shielding layer (2, 2a);

- a step of stabilizing said resin matrix (4, 4a).

13. The method according to claim 12, characterized in that said step of stabilization comprises a step of forming by heating and compression of said shielding layer (2, 2a).

14. The method according to claims 12 and 13, characterized in that it comprises a step of defining an external electrical contact which is connected electrically to said electrically conducting fabric (3, 3a).

15. The method according to one or more of the preceding claims, characterized in that said step of defining an external electrical contact comprises a step of removing the resin matrix (4) from a region of said electrically conducting fabric (3) and a step of applying a layer of electrically conducting paint (9) on said region (8) in direct contact with said electrically conducting fabric.

16. The method according to one or more of the preceding claims, characterized in that said step of defining an electrical contact comprises a step of application of an electrically conducting contact element (10a) to a region of said shielding layer (2a) in contact with said electrically conducting fabric (3 a) prior to said stabilization step and a step of removing the resin matrix (4a) from the exposed surface of said electrically conducting element (3a) after said stabilization step.

17. The method according to one or more of the preceding claims, characterized in that said step of removing the resin matrix (4, 4a) from a region of said electrically conducting fabric (3) or from said contact element (10a) consists in applying to said region of said shielding layer (2) or to said contact element (10a) a protective element (12, 12a), which is permeable to said resin matrix (4, 4a), prior to said stabilization step, and in removing said protective element (12, 12a) from said shielding layer (2) or from said contact element (10a) after said stabilization step.