JPH04252099A - Wide frequency band shielding member - Google Patents

Abstract

PURPOSE:To effectively interrupt electromagnetic waves having low frequencies and high frequencies. CONSTITUTION:Copper is deposited on the surface of a foil 17a made of amorphous alloy to form a conductive film 17b, a shielding material 17 of a flexible film is formed. The material is wound on the surface of an elastomer body 15 to form a wide frequency band shielding gasket.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide frequency band shielding member used for shielding electronic components from electromagnetic waves.

0002

[Prior Art] In recent years, various devices using electronic components such as microcomputers, office machines such as electronic typewriters and printers, household electrical appliances such as washing machines and vacuum cleaners, etc.
Additionally, automobiles and the like that electronically control fuel injection and the like are rapidly becoming popular. The number of microcomputers used has also increased, and clock frequencies have been increasing accordingly. However, due to this increase in frequency, electromagnetic wave noise generated by electronic components is radiated through gaps between the opening and closing parts and joints of the housing that houses each electronic component, and is transmitted onto surrounding signal lines. Acts directly on electronic components,
Failure to do so may result in malfunctions such as failure or malfunction of electronic components.

Furthermore, since magnetic recording elements in electronic components are made by magnetizing a magnetic material with high density using small magnetic energy, they are susceptible to adverse effects such as loss of recorded information due to external magnetic fields from electromagnets, etc. There is.

[0004] In order to prevent such disturbances due to electromagnetic waves, conventionally, electromagnetic shielding gaskets made of a highly conductive metal (hereinafter referred to as metal gaskets) or gaskets containing highly conductive metal particles or carbon black particles have been used. An electromagnetic shielding gasket made of elastomer (hereinafter referred to as elastomer gasket) is loaded into the gap in the housing.

[0005]

However, even with the use of metal or elastomer gaskets as described above, shielding of electromagnetic waves is still insufficient, and the following problems remain.

In other words, various electronic devices are not only affected by high-frequency electromagnetic waves, but also by low-frequency electromagnetic waves, so gaskets made of materials with good conductivity such as the metals and carbon mentioned above cannot be used. , it was not possible to sufficiently shield electromagnetic waves in a wide frequency band, and in some cases, there was a risk that electronic equipment would malfunction or fail.

That is, conventional metal or elastomer gaskets can shield high frequency electromagnetic waves, but have a problem in that they cannot sufficiently shield low frequency electromagnetic waves. The present invention has been made to solve the above problems, and its purpose is to provide a housing for housing electronic components with elasticity that maintains sufficient airtightness and watertightness, and to shield electromagnetic waves in a wide frequency band. An object of the present invention is to provide a wide frequency band shielding member.

[0008]

[Means for Solving the Problems] That is, the present invention, which has been made to achieve the above object, has a main body formed of a resin containing at least an elastomer, and a shield layer for shielding electromagnetic waves on the surface of the main body, A shielding member used in a portion where a plurality of members come into contact to shield electromagnetic waves passing between the members, the shielding layer comprising a foil having high magnetic permeability and flexibility, and a surface of the foil. The gist of the present invention is a wide frequency band shielding member characterized by comprising a conductive film formed on a substrate.

[0009] Here, the above-mentioned wide frequency band shielding member is a member such as a wide frequency band shielding gasket used for electromagnetic wave shielding, airtightness, and watertightness in the opening/closing part or gap of the housing, for example, Its shape includes, for example, a tube shape and a columnar shape, and its cross section can also be of various shapes such as circular, elliptical, Ω-shape, T-shape, and L-shape.

Furthermore, various elastomers such as flexible sponge rubber and silicone rubber can be used as the material constituting the main body of the broadband shielding member.

Furthermore, the material of the foil constituting the shield layer is a material having high magnetic permeability, such as Ni-Fe.
Permalloy, various amorphous alloys made of Co--Ni--Fe, 4.5% silicon-iron alloy, ferrite, etc. can be used. Note that as this ferrite, for example, manganese ferrite, magnetite, nickel ferrite, etc., which can be expressed by the chemical formula MFe2O4 (M is metal), can be used, and this ferrite has a very low electrical conductivity (10 to 106 Ωcm). have.

On the other hand, as the material of the coating formed on the surface of the foil, a metal having conductivity, such as aluminum, titanium, nickel, or copper, can be used. In addition, various methods such as vapor deposition and plating can be used for forming the layer. A coating having a thickness of 2 to 4 .mu.m is preferable because it does not impair the flexibility of the broadband shielding member and also has excellent electromagnetic wave shielding ability.

[0013]

[Function] The broadband shielding member of the present invention has a shielding layer formed on the surface of the main body made of elastomer or the like, and the shielding layer is made of a foil having high magnetic permeability and flexibility. It consists of a conductive film formed on the surface of the

[0014] Therefore, when this broadband shielding member is used in areas where multiple members come into contact, such as gaps in the housing or opening/closing parts, since the main body is flexible, it will prevent gaps between the members. The foil has a high magnetic permeability and shields low frequency electromagnetic waves, and the conductive film shields high frequency electromagnetic waves. This makes it possible to shield electromagnetic waves over a wide frequency range while maintaining high airtightness.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A gasket according to an embodiment in which a wide frequency band shielding member according to the present invention is applied to an opening/closing portion of a housing will be described below with reference to the drawings.

FIG. 1 shows that the broadband shielding gasket 1 of the first embodiment is used as a housing (case) for storing electronic components.
FIG. 3 is a partially cutaway perspective view showing the state in which the device is attached to the computer. The case 3 is made of metal and has a rectangular parallelepiped shape, and is provided with an opening 4 to accommodate electronic components. A metal case lid 5 is rotatably attached to the opening 4 via a hinge 7.

A thin film layer 6 made of an amorphous Co--Ni--Fe alloy is formed inside the case 3 and the case lid 5. Furthermore, the wide frequency band shielding gasket 1 is attached to the edge 9 of the case 3 that meets the case lid 5 using a conductive adhesive.

Furthermore, when the case lid 5 is closed, the case 3 and the case lid 5 are tightened together with the broadband shielding gasket 1 in between, thereby sealing the inside of the case 3. A tightening portion 11 is provided on the case 3 and the case lid 5. Further, a waterproof connector 13 is attached to the side surface of the case 3 for taking out signal lines (not shown) of electronic components housed in the case 3 to the outside.

As shown in FIG. 2, the broadband shielding gasket 1 described above is a tube having a rectangular cylindrical cross section, and this tube has a main body 15 made of silicone rubber with a foil 17a and a coating 17b on the surface of the main body 15. A shielding material 17 consisting of the following is wound around to form a shielding layer.

The foil 17a constituting the main part of the shielding material 17 is a flexible member having a thickness of 50 μm and made of, for example, an amorphous alloy of Co--Ni--Fe, which is a highly magnetic material. The metal coating 17b closely adhered to one surface of the foil 17a is made of conductive copper, for example, and is formed to a thickness of 1 μm by vapor deposition or the like.

[0021]The other surface of the shield material 17 has the following:
Since the glue is applied, the main body 15 and the shield material 17 can be easily formed integrally by simply wrapping the shield material 17 around the silicone rubber main body 15.

Further, as the material constituting the foil 17a, highly magnetic permalloy, various ferrites, or silicon-iron alloys can be used. On the other hand, various metals such as nickel and aluminum can be used as the conductive film 17b.

With such a configuration, the broadband shielding gasket 1 of this embodiment has the following effects. Since amorphous foil 17a, which is a highly magnetic material, is used on the surface of main body 15 of gasket 1 for wide frequency band shielding, low frequencies (10kHz to 100kHz) are used.
Hz) electromagnetic waves can be effectively shielded, and further,
Since the film 17b made of conductive copper is formed on the surface of the foil 17a, the electrical resistivity is extremely low, and therefore, it is possible to effectively shield electromagnetic waves of high frequency (1 MHz to 1000 MHz). .

As a result, the broadband shielding gasket 1 of this embodiment has the remarkable effect of being able to sufficiently shield electromagnetic waves over a wide frequency band. Furthermore, the inside of the wide frequency band shielding gasket 1 that makes surface contact with the case 3 and the case lid 5 is made of an elastic elastomer such as silicone rubber, so that it has excellent adhesion and low contact resistance. Therefore, it has a high ability to shield electromagnetic waves.

Moreover, the broadband shielding gasket 1 of this embodiment does not contain conductive particles as in the conventional case, but has a flexible shielding material 17 disposed on the surface of the silicone rubber body 15. The elasticity of the silicone rubber itself is not impaired. Therefore,
When the case lid 5 is closed, external moisture and air are reliably blocked, and the case 3 can be kept sufficiently airtight and watertight.

Furthermore, since the wide frequency band shielding gasket 1 has a rectangular cylindrical cross section, its shape is simple and the manufacturing cost of the mold can be reduced. Next, another embodiment of a tube-shaped wide frequency band shielding gasket will be described.

As shown in FIG. 3, the broadband shielding gasket 19 of the second embodiment is almost the same as the first embodiment, except that its shape is cylindrical, and the main body 21 is made of silicone rubber. A shield material 23 is wrapped around the surface of.

This shield material 23 has a thickness of 80 μm.
．． It consists of a foil 23a made of a quenched ribbon of 5% silicon-iron alloy, and a titanium coating 23b with a thickness of 2 μm formed on its surface by electroless plating. Note that this titanium coating 23b is highly durable and is therefore suitable for use in harsh environments.

Further, as shown in FIG. 4, the wide frequency band shielding gasket 25 of the third embodiment has an Ω-shaped cross section, and has a permalloy foil 29a with a thickness of 60 μm on the surface of the silicone rubber main body 27. A shielding material 29 consisting of an aluminum coating 29b having a thickness of 1 μm is attached. This broadband shielding gasket 25 includes:
Since the planar leg portions 31 and 33 are formed in the axial direction,
Easy to attach to case 3 etc.

Next, as another wide frequency band shielding gasket, an example of a wide frequency band shielding gasket made of sponge rubber other than a tube will be described. As shown in FIG. 5, the sponge rubber broadband shielding gasket 41 of the fourth embodiment has a case 4 similar to the tubular broadband shielding gasket 1 described above.
Used for the opening and closing parts of 3. That is, a broadband shielding gasket 41 made of sponge rubber and having an L-shaped cross section is attached to the upper end 47 of the side surface 45 of the case 43.

The broadband shielding gasket 41 of this embodiment is made of a foamed flexible elastomer, for example,
It is manufactured by blowing air strongly into uncured latex or adding a blowing agent (sodium bicarbonate, etc.) to elastomer that has been vigorously masticated. The surface of the main body 49 of this broadband shielding gasket 41 has a thickness of 50 mm.
A shielding material 51 consisting of a μm thick amorphous alloy foil 51a and a 1 μm thick aluminum coating 51b is attached.

As described above, the broadband shielding gasket 41 of this embodiment has excellent flexibility, so it has the advantage of having high impact resistance and being difficult to form gaps even if the opening/closing part has a complicated shape.

Further, as shown in FIG. 6, the wide frequency band shielding gasket 53 of the fifth embodiment has an inverted T-shaped cross section, and the surface thereof has four
．． A shielding material 55 consisting of a foil 55a of a quenched 5% silicon-iron alloy ribbon and a 2 μm thick nickel and copper coating 55b.
is pasted.

Further, as shown in FIG. 7, the wide frequency band shielding gasket 57 of the sixth embodiment has a circular cross section, and a 50 μm thick amorphous alloy foil 59a is provided on the surface thereof. A shielding material 59 made of a nickel film 59b having a thickness of 2 μm is wrapped around it.

The wide frequency band shielding member according to the present invention is not limited to the wide frequency band shielding gasket whose main body is made of silicone rubber or sponge rubber, but may also be made of other resins such as various elastomers. can be used. Furthermore, in addition to the above-described embodiments, various cross-sectional shapes such as a Y-shape and an anchor-shape can also be used. Further, the place of use is not limited to the opening/closing part of the case, but can be applied to the joining parts of various members.

[0036]

Effects of the Invention The present invention includes a shield layer made of a flexible foil having high magnetic permeability and a conductive film on the surface of a main body made of a resin containing an elastomer. Electromagnetic waves in a wide frequency band ranging from low frequencies to high frequencies can be effectively shielded. Furthermore, by using this broadband shielding member in a portion where a plurality of members are in contact with each other, it is possible to ensure airtightness and watertightness by closely contacting each member.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a casing in which a wide frequency band shielding gasket of a first embodiment is used.

FIG. 2 is a partially cutaway perspective view of the broadband shielding gasket of the first embodiment.

FIG. 3 is a partially cutaway perspective view of a wide frequency band shielding gasket according to a second embodiment.

FIG. 4 is a partially cutaway perspective view of a wide frequency band shielding gasket according to a third embodiment.

FIG. 5 is a partially cutaway perspective view of a gasket for wide frequency band shielding according to a fourth embodiment.

FIG. 6 is a partially cutaway perspective view of a wide frequency band shielding gasket according to a fifth embodiment.

FIG. 7 is a partially cutaway perspective view of a wide frequency band shielding gasket according to a sixth embodiment.

[Explanation of symbols]

1, 19, 25, 41, 53, 57... Gasket for wide frequency band shielding 17, 23, 29, 51, 55, 59... Shielding material 17
a, 23a, 29a, 51a, 55a, 59a... foil 17
b, 23b, 29b, 51b, 55b, 59b...film

Claims (1)

[Claims] Claim 1: A main body is formed from a resin containing at least an elastomer, and a shield layer is provided on the surface of the main body to shield electromagnetic waves, and is used in a portion where a plurality of members are in contact to block electromagnetic waves passing between the members. A wide frequency shielding member for shielding, characterized in that the shielding layer is made of a foil having high magnetic permeability and flexibility, and a conductive coating formed on the surface of the foil. Parts for band shield.