JP3113508U - Shielding materials and products that reduce electromagnetic effects - Google Patents

Abstract

A material that effectively absorbs energy associated with electromagnetic waves is provided.
SOLUTION: Separating particulate magnetic powder made of one or more materials selected from the group consisting of an electronic device or its periphery and an electromagnetic wave absorbing material Fe, Ni, Cr, Mn, silicon, rubber, acrylonitrile butadiene, And a coupling element that binds magnetic powder made of one or more materials selected from the group consisting of styrene resin, polycarbonate, epoxy, silica, and polyurethane.
[Selection] Figure 1

Description

  The present invention relates to a shielding material and a shielding product that reduce the electromagnetic wave effect, and relates to a shielding package made of a shielding material that reduces penetration of the electromagnetic wave into the shielding package.

  Electrical components of electrical products such as clock generators, integrated circuits (ICs) and central processing units (CPUs) often form electrical loops during operation. Therefore, the product is easy to generate electromagnetic waves. In addition, electrical lead wires can also generate electromagnetic waves.

  The antenna effect, that is, the radiation effect of the electromagnetic wave generated by the conductor depends on the length of the conductor and the peripheral area of the conductor. The antenna effect increases the radiation of electromagnetic waves.

  These undesirable electromagnetic waves interfere with the normal operation of other electrical products and are harmful to humans and other animals. In addition, the radiating effect of electromagnetic waves becomes more serious in electrical products for which miniaturization and high-speed transmission are pursued.

  It is known that products such as wood and plastic cannot prevent penetration of electromagnetic waves. Even metal shields cannot effectively reduce the harmful effects of electromagnetic pulses (EMP) and electromagnetic interference (EMI). Some metals can change the direction of the electric field, but do not effectively absorb electromagnetic waves. Therefore, electromagnetic energy exists in and around the metal shielding material.

  It has been practiced to reduce the radiation of electromagnetic waves generated by an antenna using capacitance. Electromagnetic radiation has also been reduced using ferrite cores and inductances. However, these methods cannot be used, for example, to protect the electrical elements in the package.

  Thus, it is desirable to provide materials and products that reduce the effect of electromagnetic waves generated by electrical products on the surrounding environment. It would also be desirable to protect electrical products from damage by external EMP or subordination to EMI.

  In view of the current state of the prior art, an object of the present invention is to provide a shielding material having a large electromagnetic shielding effect.

  Another object of the present invention is to provide a shielding layer made of an EM absorbing material.

  For this reason, the shielding material for reducing the electromagnetic wave effect of the present invention has an electronic element or its periphery, separated particulate magnetic powder made of one or more kinds of electromagnetic wave absorbing materials, and a coupling element for coupling the magnetic powder. The gist.

  Further, the shielding material of the present invention may contain a certain type of associative element to cure the shielding layer or provide a treatment agent that imparts rigidity.

  The separated particulate EM absorbing material or compound is referred to herein as magnetic powder. The magnetic powder is made of one or more metals such as Fe, Ni, Cr, and Mn, but may be made of a dielectric compound having magnetism.

  The binding compound is selected from silicon, rubber, acrylonitrile / butadiene / styrene resin (ABS), polycarbonate (PC), epoxy, silica, polyurethane and the like.

  The associating element is selected from zinc oxide, magnesium oxide, ethylene / thiourea, carbon black, stearic acid, and the like.

  The material composition is made by mixing selected elements in a weight ratio that maximizes energy transfer for a given range of frequencies.

  The material can be integrated into the packaging material for one or more electronic elements in the electronic product.

  By energy absorption, at least a part of the electromagnetic wave that has encountered the material is converted into thermal energy, and radiation of the electromagnetic wave that penetrates the material can be reduced.

  The presence of the shielding layer can prevent the electromagnetic waves generated by the electronic elements in the layer from exerting undesirable or harmful effects on the periphery. Furthermore, the shielding layer prevents the electrical product in the package from being damaged or interfered by external electromagnetic waves.

  FIG. 1 to FIG. 4 show a shielding layer made of the EM absorbing composition of the present invention, which composition contains at least one magnetic powder and at least one binding compound that binds the magnetic powder in the layer. It is what.

  In addition, the composition may have one or more associated compounds that alter the stiffness of the layer.

  Magnetic powder consists of one or more elements or compounds having magnetism. The element or compound may be conductive or dielectric. For example, the magnetic powder is made of Fe, Ni, Cr, Mn, or a combination thereof.

  The binding compound is selected from silicon, rubber, acrylonitrile / butadiene / styrene resin (ABS), polycarbonate (PC), epoxy, silica, polyurethane and the like.

  The association compound is selected from zinc oxide, magnesium oxide, ethylene / thiourea, carbon black, stearic acid, and the like.

  Due to the electromagnetic absorption of the compound, the electronic elements placed in the shielding package are effectively protected from external electromagnetic pulses (EMP) and electromagnetic interference (EMI). Furthermore, the shield package prevents electromagnetic waves generated by electronic elements disposed in the shield package from penetrating the package.

  FIG. 1 shows a shielding case of the present invention made of a cured shielding material. When the electronic element is disposed in the case, the electronic element is protected from damage or interference by an external electromagnetic wave. The case also prevents electromagnetic waves generated by the electronic elements in the case from having harmful or undesirable effects on the periphery.

  FIG. 2 shows a shielding case having two or more chambers that accommodate a plurality of electrical elements. These chambers are separated by a partition wall made of the shielding material of the present invention. Thus, the electrical elements arranged in the shielding package are protected from electromagnetic waves generated by the electrical elements in the surrounding compartment.

  Generally, the magnetic powder and one or more binding compounds make up 60-90% by weight of the composition. The particle size of magnetic powder (for example, manufactured by Fluka, Switzerland) is 1 to 200 μm, the density is 1 to 20 g / ml, and 30 to 90% by weight is present. If the shielding layer is quite thick, the magnetic powder may be coarse with large particles. Magnetic powder generally contains separated particles of a certain size depending on the use.

  The binding material is made of at least one of silicon, rubber, ABS, PC, epoxy, silica, and polyurethane. The binding material is included in the composition in an amount of 5 to 65% by weight.

  Associating elements selected from zinc oxide, magnesium oxide, ethylene / thiourea, stearic acid, and carbon black are present in a total amount of 5 to 40% by weight.

  One method for forming the shielding layer will be described below. The blend of blended compositions is heated in a mold at a temperature of about 130-190 ° C. for about 3-30 minutes to form a rigid shell of the desired shape and dimensions with a thickness of 0.1-20 mm. Depending on the mold shape, the shell may be flat, curved, circular or the like.

  For shielding cases with two or more compartments, form a partition wall with the shell, as shown in FIG. 2, or add individual sheets of one or more shielding materials to the shell and add between the compartments. An electromagnetic wave barrier can be formed.

  Depending on the type and amount of associating elements in the composition, the shielding layer can be placed in a bag as a flexible sheet to shield electronic elements and circuits from external EMP or EMl. The flexible sheet may be used, for example, to envelop the circuit board as shown in FIG.

  The shielding material can be a paste-like substance and can be selectively applied to a small part of the circuit board, for example, as shown in FIG.

  Depending on the mixture, the electromagnetic material of this invention can be made into a material on the sponge by different methods.

  Electromagnetic waves from outside the electronic element or the shielding layer are prevented from passing through the shielding layer by absorption. However, the heat generated by absorption is generally lower than the heat generated by current consumption in the electrical element.

  The EM shielding material of this device can be used as a packaging material for electronic elements in electronic products. EM shielding materials are used as packaging materials for general integrated circuits (ICs) or special application integrated circuits (ASICs). The shielding material can also be used as a package shell for an RF receiver. As shown in FIG. 5a, the EM shielding material of the present invention can be used as a total packaging material for ICs. However, the shielding material can also be used as part of the package as shown in FIGS. 5b and 5c.

  FIG. 6 shows how the magnetic powder is dispersed in the shielding layer. As shown in the figure, the separated particles in the magnetic powder are separated by the binding material, and transfer to the adjacent particles due to electric conduction of the electromagnetic waves absorbed in the particles is prevented. Thus, the electromagnetic waves absorbed by the particles are locally captured, and the energy accompanying the electromagnetic waves is transferred to the surrounding area as heat.

  Several experimental examples of the composition for forming the shielding layer are shown below.

Experimental Example 1.
(1) Prepare a material composition having a total amount of 100 g, a size of 15 μm, and a density of 4 g / ml, including magnetic powder 70 g, rubber 15 g, zinc oxide 3 g, magnesium oxide 4 g, ethylene thiourea 2 g, carbon black 4 g, and stearic acid 2 g. Mix.
(2) The mixed material is put into a mold or a container and heated to 180 ° C. for 15 minutes.
(3) A pressure of 150 kg / cm ² is applied to the mixed material.
(4) Cool the mixed material.
(5) Remove the cured material from the mold.
A shielded package made of a mixed material with a thickness of about 3 mm is effective against electromagnetic waves in the Bluetooth frequency band (S frequency band of 2-4 GHz).

Experimental Example 2.
(1) Prepare a material composition having a total amount of 100 g, a size of 20 μm, and a density of 3 g / ml, including 55 g of magnetic powder, 30 g of silicon, 3 g of zinc oxide, 4 g of magnesium oxide, 2 g of ethylene thiourea, 4 g of carbon black and 2 g of stearic acid. Mix.
(2) The mixed material is put into a mold or a container and heated to 130 ° C. for 10 minutes.
(3) A pressure of 130 kg / cm ² is applied to the mixed material.
(4) Cool the mixed material.
(5) Remove the cured material from the mold.
A shielded package made of a mixed material with a thickness of 1.6 mm is effective against electromagnetic waves in the satellite communication frequency band (12 to 18 GHz Ku frequency band).

Absorption measurement 1.
The absorption of electromagnetic waves in the Bluetooth frequency band (S frequency band of 2 to 4 GHz) is measured using the shielding package made of the mixed material of Experimental Example 1. Data on the electromagnetic wave absorption effect is shown in FIG. In the figure, the horizontal axis X represents the electromagnetic wave frequency (GHz), and the vertical axis Y represents the return loss (db). It was found that electromagnetic energy was converted to thermal energy, resulting in negligible temperature rise.

Absorption measurement 2.
The electromagnetic wave absorption in the satellite communication frequency band (12 to 18 GHz Ku frequency band) was measured using the shielding package from the mixed material of Experimental Example 2. Data on the electromagnetic wave absorption effect is shown in FIG. In the figure, the horizontal axis X represents the electromagnetic wave frequency (GHz), and the vertical axis Y represents the return loss (db).

  In addition to the shielding layer, a second shielding unit may be added on the shielding layer. This increases the transfer capability of the energy transfer unit. The second shielding layer is made of a metal sheet of gold, silver, copper, iron, aluminum, platinum, stainless steel, ITO, an alloy or an electromagnetic shielding film without ground.

  Furthermore, the shielding layer of the present invention can be thicker or thinner depending on the degree of protection desired. The shielding layer can also be formed from several sub-layers of mixed material.

  The inventive shielding product made of EM absorbing material can also be a hard shell or paste as shown in FIGS. However, the product can be made more liquid and sprayed or painted onto one or more electronic elements.

  A second shielding layer can be added adjacent to the EM shielding layer to enhance the energy transfer capability of the EM shielding layer. The second shielding layer is formed of a metal or a metal compound such as gold, silver, copper, iron, aluminum, platinum, stainless steel.

It is sectional drawing of the shielding case in one Example of this device. It is sectional drawing of the shielding case in the other Example of this invention. It is a model figure of the flexible shielding layer which envelops an electronic element. It is a model figure of the shielding material used as a paste applied to an electronic element. It is a model figure of the shielding material used as a package material for the electronic elements in an electronic product. It is a model figure of the shielding material used as a part of package material for electronic elements in an electronic product. It is a model figure of the shielding material used as an inner part of the packaging material for electronic elements in an electronic product. It is a model figure which shows the coupling | bonding of the magnetic powder in a shielding layer. It is a graph which shows the microwave characteristic of the shielding package of this device in case the electromagnetic waves used for the absorption measurement are in the Bluetooth frequency band (S frequency band = 2-4 GHz). It is a graph which shows the microwave characteristic of the shielding package of this device in case the electromagnetic waves used for the absorption measurement are in the satellite communication band (Ku frequency band = 12 to 18 GHz).

Claims (20)

  A shielding material for reducing an electromagnetic wave effect, comprising: an electronic element or its periphery; a separated particulate magnetic powder made of one or more kinds of electromagnetic wave absorbing materials; and a coupling element for binding the magnetic powder.   The shielding material according to claim 1, wherein the one or more electronic elements have a packaging material surrounding them, and the shielding material is integrated in the packaging material.   The shielding material according to claim 1, wherein one or more electronic elements are encapsulated in a package including a plurality of envelope layers, and the shielding material is integrated in the one or more envelope layers. .   The shielding material according to claim 1, wherein the magnetic powder is made of one or more metal materials or compounds.   The shielding material according to claim 1, wherein the magnetic powder is made of one or more materials selected from the group consisting of Fe, Ni, Cr, and Mn.   The shielding material according to claim 1, wherein the magnetic powder includes one or more dielectric materials having magnetism.   2. The shielding material according to claim 1, wherein the binding material is made of one or more materials selected from the group consisting of silicon, rubber, acrylonitrile / butadiene / styrene resin, polycarbonate, epoxy, silica, and polyurethane.   The shielding material according to claim 1, further comprising an associating element for determining physical properties of the shielding material in the treated product.   2. The shielding material according to claim 1, wherein the associating element is selected from zinc oxide, magnesium oxide, ethylene / thiourea, carbon black, and stearic acid.   A shielding product shared with an electronic device, the product comprising a material composition that is processed to form a layer, the layer being placed near one or more electronic devices, whereby the layer is one The above-described material composition absorbs electromagnetic waves in the vicinity of the electronic device, and the material composition includes magnetic particles made of separated particle-shaped electromagnetic wave absorbing devices, and a coupling device that combines the magnetic particles in the layer. Product.   The product of claim 10, wherein the electronic device is encapsulated in the package material and the layer is part of the package material.   11. A product as claimed in claim 10, characterized in that one or more electronic elements are encapsulated in the layer.   11. The product of claim 10, wherein one or more electronic elements are surrounded by a package material having a layer structure, and the layer is part of the layer structure.   The product according to claim 10, wherein the magnetic powder is made of one or more materials selected from the group consisting of Fe, Ni, Cr, and Mn.   11. The product according to claim 10, wherein the binding material is made of at least one material selected from the group consisting of silicon, rubber, acrylonitrile / butadiene / styrene resin, polycarbonate, epoxy, silica, and polyurethane.   11. A product according to claim 10, further comprising an associating element for determining the physical properties of the layer.   The product according to claim 16, characterized in that the associating element is selected from zinc oxide, magnesium oxide, ethylene thiourea, carbon black and stearic acid.   A shielding product shared with an electronic device, wherein the product is processed to form a paste applied on or near one or more electronic devices to absorb electromagnetic waves in the vicinity of the one or more electronic devices. A shielding material characterized by comprising a material composition, wherein the material composition comprises magnetic particles in the form of separated particles composed of one or more electromagnetic wave absorbing elements, and a coupling element that binds the magnetic particles in the layer. Product.   The magnetic powder is made of one or more materials selected from the group consisting of Fe, Ni, Cr, Mn, and the binding material is selected from the group consisting of silicon, rubber, acrylonitrile / butadiene / styrene resin, polycarbonate, epoxy, silica, polyurethane. The product according to claim 18, comprising at least one material.   The product according to claim 18, further comprising an associating element that determines physical properties of the paste, wherein the associating element is selected from zinc oxide, magnesium oxide, ethylene thiourea, carbon black, and stearic acid. .

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