KR102310727B1 - Housing for electromagnetic shielding - Google Patents

Abstract

The present invention relates to a housing for electromagnetic shielding. The present invention includes a body made of plastic and a shielding layer composed of at least one of Al, Si, V, Cr, Fe, Co, Ni, Cu, Zn, Ag and Sn, and coated on at least a part of the body surface, A portion of the shielding layer provides a plastic housing, characterized in that it is formed by being solidified while penetrating the plastic surface. As described above, according to the present invention, the metal or alloy coating layer can be attached to the plastic surface with high adhesion strength. Accordingly, according to the present invention, a main material constituting a housing for an electronic component is made of a light reinforced plastic, and a metal or alloy having a shielding function can be coated on the plastic surface. Since the proportion of a relatively heavy metal or alloy in the housing according to the present invention is very low, according to the present invention, it is possible to provide a housing that is lighter than a housing of a conventional electronic component and has an electromagnetic shielding function.

Description

HOUSING FOR ELECTROMAGNETIC SHIELDING

The present invention relates to a housing for electromagnetic shielding.

Electromagnetic shielding refers to not radiating noise generated inside an electronic component to the outside of the case, or blocking noise from intruding from the outside. Electronic components that generate a large amount of electromagnetic waves or are sensitive to external electromagnetic waves must be shielded from electromagnetic waves, and for this purpose, the housing of the electronic components is made to have electromagnetic shielding ability.

Meanwhile, electromagnetic shielding may be broadly classified into two types.

First, there is magnetic field shielding. For magnetic field shielding, a method of using a material with high magnetic permeability to pass a magnetic force line through a magnetic field shielding part with low magnetic resistance is used. In this case, iron, permalloy, etc. are mainly used as the shielding material, and the thicker the plate, the greater the effect.

Second, there is electric field shielding. In order to shield the electric field, a method of applying zinc spray, plating, or conductive paint to the surface of a metal case or a plastic case, and a method of imparting conductivity to the plastic itself used in the case are used.

As described above, a conductive metal is mainly used as a material for electromagnetic shielding. For electromagnetic shielding, there may be a method in which the housing of the electronic component is made of metal, but this increases the weight of the electronic component.

On the other hand, the main skeleton of the electronic part housing is made of light plastic and there is a method of coating a metal on the plastic surface. In particular, there is a problem in that the metal coated on the plastic surface is peeled off by thermal shock due to temperature change.

An object of the present invention is to provide an electronic component housing that is lighter than a conventional housing and has excellent shielding ability in order to solve the above problems.

Specifically, an object of the present invention is to provide an electronic component housing having an electromagnetic shielding layer that can be attached to a plastic surface with high adhesion strength, and a method for manufacturing the same.

In order to achieve the above object, the present invention allows the shielding layer to have high adhesion strength to the plastic surface.

In a specific embodiment, the present invention consists of a body made of plastic and at least one of Al, Si, V, Cr, Fe, Co, Ni, Cu, Zn, Ag and Sn, and a shield coated on at least a part of the body surface It provides a plastic housing comprising a layer, wherein a portion of the shielding layer is solidified while penetrating the plastic surface.

In one embodiment, the thickness of the shielding layer may be 5 to 300㎛.

In an embodiment, the sheet resistance of the shielding layer may be 0.01 Ω/sq or less.

In an embodiment, the porosity of the shielding layer may be 5% or less.

In an embodiment, irregularities may be formed on the surface of the body where the shielding layer is coated. Through this, it is possible to improve the adhesion strength of the shielding layer.

In an embodiment, the shielding layer may be formed of a plurality of layers. Through this, it is possible to utilize the advantages of each of the materials constituting the plurality of layers.

In addition, the present invention provides a step of performing a surface treatment on the body so that irregularities are formed on the surface of the body made of plastic, and Al, Si, V, Cr, Fe, Co, Ni, Cu, Zn, Electromagnetic shielding for a plastic housing, comprising the step of spraying a metal or alloy in a molten state, comprising at least one of Ag and Sn, wherein the spraying speed of the metal or alloy in the molten state is 300 to 500 m/s A layer coating method is provided.

As described above, according to the present invention, the metal or alloy coating layer can be attached to the plastic surface with high adhesion strength. Accordingly, according to the present invention, a main material constituting a housing for an electronic component is made of a light reinforced plastic, and a metal or alloy having a shielding function can be coated on the plastic surface.

Since the proportion of a relatively heavy metal or alloy in the housing according to the present invention is very low, according to the present invention, it is possible to provide a housing that is lighter than a housing of a conventional electronic component and has an electromagnetic shielding function.

1 is a perspective view illustrating an electronic component housing according to an embodiment of the present invention.
Fig. 2 is a cross-sectional view taken along line A-A' in Fig. 1;
3 and 4 are enlarged views of part B of FIG. 2 .
5 is a cross-sectional view of a housing including a body having a concave-convex structure.
6 is a cross-sectional photograph of a housing according to an embodiment of the present invention.
7 is a graph showing the results of the shielding performance test of the housing described in FIG. 6 .
8 is a cross-sectional view of a housing including a shielding layer made of a plurality of layers.
9 is a cross-sectional photograph of a housing including a shielding layer formed of a plurality of layers.
10 is a graph showing the results of the shielding performance test of the housing described in FIG. 9 .

Hereinafter, the embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but the same or similar components are assigned the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted. In addition, in describing the embodiments disclosed in the present specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed herein is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present invention , should be understood to include equivalents or substitutes.

Terms including an ordinal number, such as first, second, etc., may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present application, terms such as "comprises" or "have" are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

1 is a perspective view illustrating an electronic component housing according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line A-A' of FIG. 1 .

The housing serves to physically or chemically protect the parts built into the housing from the outside. The housing of FIG. 1 allows the electronic component to form a cylindrical appearance. In this specification, a cylindrical housing will be described, but the shape of the housing is not limited thereto, and may vary depending on the shape of the electronic component.

Meanwhile, referring to FIG. 2 , the interior of the housing is made of an empty space by a plurality of outer walls. Components constituting the electronic component are disposed at positions where the empty space is formed. The outer walls absorb external shocks and prevent foreign substances from entering the housing. A shielding layer may be coated on the surfaces of the outer walls.

3 and 4 are enlarged views of part B of FIG. 2 .

Referring to FIG. 3 , the outer wall of the housing according to an embodiment of the present invention may include a body 110 made of plastic and a shielding layer 120 coated on the body surface.

Here, the surface of the body 110 may be formed of an outer surface facing the outside of the housing and an inner surface facing the inside of the housing. The shielding layer 120 may be coated on at least one of an outer surface and an inner surface of the body 110 .

For example, referring to FIG. 3 , the shielding layer 120 may be coated on the outer surface of the body 110 . In this case, the shielding layer 120 is disposed to face the outside, and the appearance of the housing is determined according to the material of the shielding layer 120 .

For another example, referring to FIG. 4 , the shielding layer 120 may be coated on the inner surface of the body 120 . In this case, the shielding layer 120 is disposed to face the inside, and the exterior of the housing is determined according to the material of the plastic constituting the body 110 .

Meanwhile, although not shown, the shielding layer 120 may be disposed on each of the outer and inner surfaces of the body.

Hereinafter, the body 110 and the shielding layer 120 will be described in detail.

The body 110 is a basic skeleton that determines the shape of the housing according to the present invention. The body 110 may be processed into various shapes according to the shape of the electronic component. The body 110 may be made of plastic to reduce the weight of the housing. Specifically, plastics are Acrylonitrile-butadiene-styrene(ABS), Polypropylene(PP), Polyethylene(PE), polystyrene(PS), Polycarbonate(PC), Polyphenylene Oxide(PPO), Polyamide6(PA6), Polyamide66(PA66), A thermoplastic resin comprising at least one of PolyOxyMethylene (POM), Polybutylene terephthalate (PBT), Polyethylene Terephtalate (PET), Polyphenylene sulfide (PPS), Polyetheretherketone (PEEK), Liquid-crystal polymers (LCP), Polyphthalamide (PPA), or It may be made of a thermosetting resin including at least one of phenol, urea, melamine, alkyd, unsaturated polyester, epoxy, silicone and polyurethane, or a composite resin in which a thermoplastic resin and a thermosetting resin are mixed.

Meanwhile, in order to increase the strength of the housing, the plastic may include an additive. Here, the additive may be at least one of glass fibers, carbon-based fillers (carbon nanotubes, graphene, graphene nanoplatelets, carbon black, graphite, etc.), nanofibers, nanocellulose, and talc. Additives are 1 to 50 wt. based on the total mass of the plastic. % can be added. The content of the additive in the plastic is 1 wt. %, the effect of increasing the strength of the plastic is small, and 50 wt. %, there is a problem that the flowability during injection molding is lowered and processing becomes difficult. Preferably, the content of the additive is 30wt. It can be %.

The specific gravity of the plastic is 1.1 to 1.5, which is lighter than the aluminum alloy (specific gravity 2.7) that has been used as a conventional metal housing. Accordingly, when the plastic is used as the housing of the electronic component, the weight of the electronic component can be reduced. However, since the plastic has little electromagnetic shielding ability, the shielding layer 120 should be coated on the surface of the plastic. Hereinafter, the shielding layer 120 will be described in detail.

The shielding layer 120 is a metal or alloy including at least one of Cu, Ni, Al, Zn, Sn, Fe, Co, Cr, Ag, and V.

The shielding layer 120 is coated by melt spraying on the surface of the body 110 . Here, melt spraying is a technique for forming a metal coating film by spraying a molten metal on the surface of an object at a high speed.

Since the metal in the molten state is very high temperature, when the metal in the molten state comes into contact with the surface of the body 110 , a portion of the surface of the body 110 may be melted. Accordingly, the metal in the molten state can penetrate the surface of the body 110 . Thereafter, referring to FIG. 3 , the molten metal is solidified in a state 120a penetrating the surface of the body 110 .

As described above, since a portion of the shielding layer 120 penetrates into the surface of the body 110 , the shielding layer 120 can have high adhesion strength.

Here, the shielding layer 120 must have an adhesion strength of at least a certain level, and must have a shielding ability of a certain level or more. Hereinafter, each of the shielding layer 120 will be described from the above two viewpoints.

In the present specification, the adhesive strength was measured according to the test standard ASTM D4541-09e1, the test device was PosiTest AT (Defelsko-USA), and the test speed was 1 MPa/s. Specifically, the test method is a pull-off test method. After attaching and curing a dolly (diameter 20mm) with type 2 epoxy to a metal film coated on plastic, pulling the attached dolly and measuring the pressure when it falls off. All of the adhesion strengths referred to in this specification are adhesion strengths measured in the above-described manner.

On the other hand, the porosity of the shielding layer 120 affecting the adhesion strength and shielding ability was measured using an image analysis program (Gwyddion) after taking a scanning electron microscope (SEM) image of a cross-section of the metal coating film using an electron microscope. . The porosity mentioned in this specification are all porosity measured in the above-mentioned manner.

First, when describing the adhesion strength of the shielding layer 120 , the adhesion strength of the shielding layer 120 should be 2.5 MPa or more. When the adhesive strength of the shielding layer 120 is less than 2.5 MPa, the shielding layer 120 may be peeled off by thermal shock occurring between -40 and 95°C.

There are two major factors that can affect the adhesion strength. Specifically, the porosity of the shielding layer 120 and the surface state of the body 110 . Hereinafter, the two factors described above will be described in detail.

First, the porosity of the shielding layer 120 should be formed to be 5% or less. When the porosity exceeds 5%, the adhesion strength of the shielding layer 120 may be less than 2.5 MPa, and the contact surface with oxygen is widened, and oxidation of the shielding layer 120 is accelerated. Oxidation of the shielding layer 120 is a factor that reduces the adhesion strength of the shielding layer 120, so it is desirable to minimize it. On the other hand, the porosity of the shielding layer 120 may be controlled by the spraying speed of the molten metal when the shielding layer 120 is coated. This will be described later together with the coating method.

However, there may be a specific metal or alloy having high adhesion to a specific material constituting the body 110 . Specifically, a metal or alloy having excellent adhesion to the plastic surface may have an adhesive strength of 2.5 MPa or more even if the porosity exceeds 5%. For example, when Zn metal is coated on the polycarbonate surface, even if the shielding layer 120 has a porosity of 10% to 15%, the shielding layer 120 has an adhesion strength of 2.5 MPa or more. However, when the porosity is more than 5%, oxidation of the shielding layer 120, increase in sheet resistance, etc. may be a problem, so the porosity is preferably 5% or less.

On the other hand, when the porosity of the shielding layer 120 is 3% or less, the adhesion strength of the shielding layer 120 is further increased. Specifically, when the porosity of the shielding layer 120 is 3% or less, the adhesion strength of the shielding layer 120 may be 6.0 MPa or more.

Second, the rougher the surface of the body 110 is formed, the more the contact area with the shielding layer 120 increases, thereby increasing the adhesion strength. In order to increase the contact area between the body 110 and the shielding layer 120 , a concave-convex structure may be formed on the surface of the body 110 separately from the penetration of the shielding layer 120 into the surface of the body 110 .

Specifically, referring to FIG. 5 , a plurality of irregularities 110a may be formed on the surface of the body 110 . The irregularities 110a increase the contact area between the body 110 and the shielding layer 120 to increase the adhesion strength of the shielding layer 120 . A method of forming the unevenness 110a on the surface of the body 110 will be described later.

As described above, the adhesion strength of the shielding layer 120 should be 2.5 MPa or more. In particular, when the housing according to the present invention is used in an environment with large temperature changes (eg, a battery housing of an electric vehicle), the shielding The adhesive strength of the layer 120 is preferably 6.0 MPa or more. On the other hand, the shielding layer 120 should have a shielding ability of a certain level or more.

Hereinafter, the shielding ability of the shielding layer 120 will be described. The shielding layer 120 to be described later is described as having a shielding ability of 80 dB or more at 30 MHz to 1.5 GHz, but is not limited thereto.

There are three major factors affecting the shielding ability. Specifically, the sheet resistance of the shielding layer 120 , the thickness of the shielding layer 120 , and the material constituting the shielding layer 120 . Hereinafter, the three factors described above will be described in detail.

First, the sheet resistance of the shielding layer 120 should be 0.01 Ω/sq or less. The sheet resistance refers to electrical conductivity of the shielding layer 120 . Since the shielding ability of the shielding layer 120 increases as the electrical conductivity of the shielding layer 120 increases, it is preferable that the sheet resistance of the shielding layer 120 be low. In order for the shielding layer 120 to have a shielding ability of 80 dB or more, the sheet resistance of the shielding layer 120 should be 0.01 Ω/sq or less.

Here, since the sheet resistance of the shielding layer 120 increases as the porosity of the shielding layer 120 increases, the porosity is preferably 5% or less.

Second, the thickness of the shielding layer 120 should be 5 μm or more. As the thickness of the shielding layer 120 increases, the shielding ability 120 increases. The minimum thickness for the shielding layer 120 to have a shielding ability of 80 dB or more is 5 μm. However, the thickness of the shielding layer 120 is preferably formed to be 50㎛ or more. Due to the characteristics of the melt spraying method, it is not easy to control the metal or alloy layer to a thickness of less than 50 μm. For this reason, when the shielding layer 120 is formed to be less than 50 μm, the shielding layer 120 may be non-uniformly formed.

On the other hand, the thicker the shielding layer 120, the better the shielding ability, but there is a disadvantage of increasing the weight of the housing. When the thickness of the shielding layer 120 exceeds 300 μm, even if the thickness of the shielding layer 120 increases, the shielding ability is not significantly improved. Accordingly, the thickness of the shielding layer 120 is preferably formed to be 300 μm or less.

Third, the electromagnetic shielding ability may be different depending on the type of metal or alloy. In particular, the shielding ability of the magnetic field shielding field greatly differs depending on the type of metal or alloy. In order to improve the magnetic field shielding ability, the shielding layer 120 may be made of any one of Fe, Co, Ni, Fe-Co, Fe-Ni, Fe-Si, and Co-Ni.

As described above, the sheet resistance of the shielding layer 120 should be 0.01 Ω/sq or less, and the thickness should be 5 μm or more. Meanwhile, in order for the housing according to the present invention to have a high magnetic field shielding ability, the shielding layer 120 is made of any one of Fe, Co, Ni, Fe-Co, Fe-Ni, Fe-Si, and Co-Ni metal. should be done with

In one embodiment, after forming a shielding layer made of Zn metal on the surface of a reinforced plastic made of PA66 and 30 wt.% of glass fiber, the electromagnetic wave shielding ability was measured according to ASTM D4935 standard. A cross-sectional photograph of the housing according to the embodiment is shown in FIG. 6 , and the measurement result of the electromagnetic wave shielding ability is shown in FIG. 7 .

Referring to FIG. 6 , the thickness of the zinc metal layer (white) is about 100 μm, and it can be seen that the zinc metal is solidified while penetrating the plastic surface. Meanwhile, the sheet resistance of the zinc metal layer was measured to be 0.002 Ω/sq or less, and the average adhesive strength was 6.0 MPa.

Referring to FIG. 7 , it can be seen that the housing according to the embodiment has a shielding ability of 80 dB or more at 30 MHz to 1.5 GHz.

According to the above-described embodiment, it can be confirmed that the shielding layer 120 included in the housing according to the present invention has high adhesion strength and excellent shielding ability.

In the above, the housing according to the present invention has been described. Hereinafter, modified examples of the housing according to the present invention will be described.

The shielding layer 120 included in the housing according to the present invention may be formed of a plurality of layers. As described in FIG. 3 , the adhesion strength and shielding ability of the shielding layer 120 may vary depending on the material constituting the shielding layer 120 . For example, there may be a material having high adhesion strength to plastic but low shielding ability, and there may be a material having low adhesion strength to plastic but high shielding layer. When the shielding layer 120 is composed of layers of different materials, only the advantages of each of the plurality of materials can be utilized.

8 is a cross-sectional view of a housing including a shielding layer 120 made of a plurality of layers.

Referring to FIG. 8 , it may include a first layer 121 stacked on the body surface and a second layer 122 stacked on the first layer 121 . However, the housing 100 described in FIG. 6 does not limit the number of layers constituting the shielding layer 120 to two. The shielding layer 120 may further include at least one layer stacked on the second layer 122 .

The first layer 121 is a layer in contact with the body 110 and must have high adhesion strength. The first layer 121 is solidified in a state 121a penetrating the surface of the body 110 like the shielding layer 120 described with reference to FIG. 3 . Meanwhile, since the second layer 122 is laminated on the first layer 121 , the adhesive force with the first layer 121 must be high.

As described above, the first and second layers 121 and 122 have different physical properties. Hereinafter, for convenience of description, the physical properties between the first and second layers 121 and 122 are compared and described.

First, the adhesion strength of the first and second layers 121 and 122 to plastics, respectively, will be described. The first layer 121 may be a material having a higher adhesive strength to plastic than the second layer 122 . Since the first layer 121 is a layer in contact with the body 110 , adhesive strength with the plastic constituting the body 110 must be high. On the other hand, since the second layer 122 is not a layer that is in substantially contact with the body 110 , the adhesive force of the second layer 1220 to the plastic does not need to be high.

Next, the electrical conductivity of the metal or alloy of the second layer 122 may be higher than that of the metal or alloy constituting the first layer 121 . When the first layer 121 is made of a material having high adhesion strength to plastic, the advantages of the first layer 121 having high adhesion strength to plastic and the second layer 122 having good shielding ability 122 You can take advantage of both at the same time.

Next, adhesion strength between the first and second layers 121 and 122 will be described. When the shielding layer 120 is composed of a plurality of layers, delamination between layers may be a problem. To solve this, the melting point of the material forming the second layer 122 may be higher than the melting point of the material forming the first layer 121 . The second layer 122 is melt-spun on the surface of the first layer 121 . At this time, when the melting point of the material to be spun is higher than that of the first layer 121 , a portion of the first layer 121 may be melted. . Accordingly, the materials constituting each of the first layer 121 and the second layer 122 may be mixed with each other in a molten state to form an alloy.

As described above, an alloy in which materials constituting each of the first and second layers 121 and 122 are mixed may be formed between the first and second layers 121 and 122 . The alloy layer formed between the first and second layers 121 and 122 may increase adhesion strength between the first and second layers 121 and 122 .

Next, the thickness of the first and second layers 121 and 122 will be described. In order for the shielding layer 120 to have a shielding ability of 80 dB or more, the sum of the thicknesses of the first and second layers 121 and 122 must be 5 μm or more.

Here, when the second layer 122 is higher than the electrical conductivity of the metal or alloy constituting the first layer 121 than the electrical conductivity of the metal or alloy, the thickness of the first layer 121 is that of the second layer 122 . It is preferably smaller than the thickness. Specifically, the present invention minimizes the thickness of the first layer 121 to secure only the adhesion to the plastic surface, and maximizes the thickness of the second layer 122 to maximize the shielding ability of the shielding layer 120 . can do.

Finally, the porosity of the first and second layers 121 and 122 will be described. When the adhesive force of the material constituting the first layer 121 to the plastic is high, the porosity of the first layer 121 is not necessarily 5% or less. Since the first layer 121 is covered by the second layer 122, the possibility of oxidation is low even if the porosity exceeds 5%, and since it does not perform the main shielding function, the shielding layer 120 has a high sheet resistance. It does not significantly affect the shielding ability.

However, since the second layer 122 is exposed to the outside when there is no other layer covering the second layer 122 , there is a risk of oxidation, and better shielding than the first layer 121 for securing adhesion to plastics Because it should have a porosity, the porosity should be low. That is, the porosity of the second layer 122 should be lower than that of the first layer 121 .

As described above, when the shielding layer 120 is composed of a plurality of layers, it is possible to take advantage of the advantages of each of the plurality of layers.

In one embodiment, after forming a first layer made of Zn metal and a second layer made of Al metal on the surface of a reinforced plastic made of PA66 and 30 wt.% of glass fiber, the electromagnetic wave shielding ability is measured according to ASTM D4935 standard. did. A cross-sectional photograph of the housing according to the embodiment is shown in FIG. 9 , and the measurement result of the electromagnetic wave shielding ability is shown in FIG. 10 .

Referring to FIG. 9 , the thickness of the first layer was 130 to 170 μm, and the thickness of the second layer was 60 to 100 μm. It can be seen that the zinc metal is solidified in the state that it penetrates the plastic surface. On the other hand, the sheet resistance of the shielding layer was measured to be 0.001 Ω/sq or less, and the average adhesive strength was 6.0 MPa.

Referring to FIG. 10 , it can be seen that the housing according to the embodiment has a shielding ability of 80 dB or more at 30 MHz to 1.5 GHz.

As described above, even when the shielding layer 120 is composed of a plurality of layers, the shielding layer 120 may have excellent adhesion strength and shielding ability.

On the other hand, by configuring some of the plurality of layers with a material having a good magnetic field shielding ability, it is possible to improve the magnetic field shielding ability of the housing according to the present invention.

Specifically, at least one of the plurality of layers constituting the shielding layer 120 may be a magnetic layer made of any one of Fe, Co, Ni, Fe-Co, Fe-Ni, Fe-Si, and Co-Ni.

On the other hand, the thickness of the magnetic layer may be 10 to 300㎛. When the magnetic layer is formed to a thickness of less than 10 μm, it is difficult to actually expect a magnetic field shielding effect. Meanwhile, when the thickness of the magnetic layer exceeds 300 μm, the weight of the housing may be excessively increased.

In the above, the housing according to the present invention has been described. Hereinafter, a method of coating the shielding layer included in the above-described housing will be described.

In the present invention, the shielding layer 120 is formed by rapidly spraying molten metal on the surface of the plastic body 110 processed in a certain shape. In this case, a method of melting metal powder using a plasma jet as a heat source and spraying a molten metal using compressed air may be utilized. However, the melt spraying method is not limited thereto.

Meanwhile, the porosity of the shielding layer 120 may vary according to the injection speed of the molten metal. Specifically, the injection speed of the molten metal should be 300 to 500 m/s. When the injection speed of the molten metal is less than 300 m/s, the size of the particles constituting the shielding layer 120 increases, thereby increasing the porosity. On the other hand, when the injection speed exceeds 500 m/s, the metal is not well deposited on the surface of the body 110 .

On the other hand, the melt spraying method is difficult to control when the coating layer is formed to a thickness of 50 μm or less. In order to form the shielding layer 120 with high uniformity by the melt spraying method, the thickness of the shielding layer 120 should be 100 to 200 μm.

Meanwhile, in order to improve the adhesion strength of the shielding layer 120 , a surface treatment step for the body 110 may be performed before spraying the molten metal. Specifically, the surface treatment step may be performed in two different ways.

First, the surface treatment step may be performed by dry surface treatment. Specifically, the surface of the body 110 may be irradiated with a plasma beam or an ion beam to form an uneven structure on the surface of the body 110 .

Also, a method in which particles having a size of 1 to 1000 μm on the surface of the body 110 collide with the body 110 may be used. Here, the particles colliding with the body 110 may be any one of SiC, Al2O3, CBN (cubic boron nitride), B4C (boron carbide, Borcarbid), WC (Tungsten carbide), TiC (Titani㎛ Carbide), and Diamond having have. Here, the injection speed of the particles may be 100 to 500 m / s.

Second, the surface treatment step may be performed by wet surface treatment. Specifically, the surface of the body 110 may be roughened by impregnating the body 110 in an aqueous solution such as NaOH or KOH.

Through the above-described surface treatment step, the adhesion strength of the shielding layer 120 can be improved.

As described above, according to the present invention, the metal or alloy coating layer can be attached to the plastic surface with high adhesion strength. Accordingly, according to the present invention, a main material constituting a housing for an electronic component is made of a light reinforced plastic, and a metal or alloy having a shielding function can be coated on the plastic surface. Since the proportion of a relatively heavy metal or alloy in the housing according to the present invention is very low, according to the present invention, it is possible to provide a housing that is lighter than a housing of a conventional electronic component and has an electromagnetic shielding function.

It is apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention.

In addition, the above detailed description should not be construed as restrictive in all respects but as exemplary. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention.

Claims (16)

A housing for electromagnetic shielding, comprising:
body made of plastic; and
A shielding layer composed of at least one of Al, Si, V, Cr, Fe, Co, Ni, Cu, Zn, Ag, and Sn, and coated on at least a portion of the body surface,
A portion of the shielding layer is formed by being solidified while penetrating the plastic surface. According to claim 1,
The thickness of the shielding layer is a housing, characterized in that 5 to 300㎛. According to claim 1,
The housing, characterized in that the adhesive strength of the shielding layer is 2.5 MPa or more. According to claim 1,
A housing, characterized in that the sheet resistance of the shielding layer is 0.01 Ω/sq or less. According to claim 1,
The housing, characterized in that the porosity of the shielding layer is 5% or less. According to claim 1,
The housing, characterized in that the unevenness is formed in the area of the surface of the body to be coated with the shielding layer. According to claim 1,
The shielding layer is
It consists of a plurality of layers,
a first layer laminated on the body surface; and
and a second layer laminated on the first layer. 8. The method of claim 7,
The adhesion strength to the body surface is,
The housing, characterized in that the metal or alloy constituting the first layer is higher than the metal or alloy constituting the second layer. 8. The method of claim 7,
The housing, characterized in that the electrical conductivity of the metal or alloy constituting the second layer is higher than the electrical conductivity of the metal or alloy constituting the first layer. 8. The method of claim 7,
A housing, characterized in that between the first and second layers, an alloy layer in which a metal or alloy constituting the first and second layers is mixed is formed. 8. The method of claim 7,
The melting point of the metal or alloy constituting the second layer is higher than the melting point of the metal or alloy constituting the first layer. 8. The method of claim 7,
The housing, characterized in that the thickness of the first layer is smaller than the thickness of the second layer. 8. The method of claim 7,
The housing, characterized in that the porosity of the first layer is greater than the porosity of the second layer. 8. The method of claim 7,
At least one of the plurality of layers is a magnetic layer comprising any one of Fe, Co, Ni, Fe-Co, Fe-Ni, Fe-Si, and Co-Ni. 15. The method of claim 14,
The housing, characterized in that the thickness of the magnetic layer is 10 to 300㎛. A method for coating an electromagnetic shielding layer on a plastic housing, the method comprising:
performing a surface treatment on the body so that irregularities are formed on the surface of the body made of plastic; and
Comprising the step of spraying a metal or alloy in a molten state, consisting of at least one of Al, Si, V, Cr, Fe, Co, Ni, Cu, Zn, Ag and Sn on the body surface,
The electromagnetic shielding layer coating method for the plastic housing, characterized in that the injection speed of the metal or alloy in the molten state is 300 to 500 m / s.

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