KR101603562B1

KR101603562B1 - Magnetic shielding sheet

Info

Publication number: KR101603562B1
Application number: KR1020150095250A
Authority: KR
Inventors: 이재희
Original assignee: 이재희
Priority date: 2015-07-03
Filing date: 2015-07-03
Publication date: 2016-03-15

Abstract

An embodiment of the present invention relates a magnetic field shielding sheet which can prevent scattering or a loss of an amorphous ribbon without a protective film by performing a braking process to the amorphous ribbon without attaching the protective film. To this end, according to an embodiment of the present invention, disclosed is the magnetic field shielding sheet which comprises: at least one electromagnetic wave absorbing sheet having a plurality of braking processed amorphous ribbons provided therein; and an adhesive film attached between the electromagnetic wave absorbing sheets. The thickness of the magnetic field shielding sheet can be between 25 to 55 μm.

Description

{MAGNETIC SHIELDING SHEET}

One embodiment of the present invention relates to a magnetic shielding sheet capable of preventing scattering or loss of an amorphous ribbon without a protective film in a breaking process, and having an excellent electromagnetic wave absorption rate.

[0002] Recently, with respect to digital electronic apparatuses, demands for higher speed, higher performance, miniaturization and thinning of product type of circuit signal processing speed of electronic apparatuses are further accelerated. In addition, data processing speeds of various semiconductor devices mounted on a printed circuit board (PCB) have been increased, and the mounting density of components mounted on a printed circuit board (PCB) has increased.

Such devices are accompanied by a rapid change of voltage and current due to high-speed signals, and thus induce inductive noise, which is a source of high frequency noise. Components such as active and passive components are located very close to each other on the printed circuit, causing problems such as cross talk due to electronic coupling between elements inside a small digital electronic device or wiring between elements and wiring, EMI (Electro Magnetic Interference) that affects other devices may be caused.

In addition, when electromagnetic waves generated from electronic devices are exposed to the human body for a long period of time, they affect the human body such as glaucoma and deterioration of reproductive ability.

Electro Magnetic Shielding (EMI shielding) proposed as a countermeasure against the above-mentioned EMI means to absorb or block electromagnetic wave noise penetrating from the outside without radiating the electromagnetic noise generated inside the electronic device out of the case.

In the case of a digital electronic device having a space inside the device, a filter may be connected to a circuit for generating inductive noise to remove noise or to reduce the distance between the circuits, shielding with an electromagnetic shielding material, And EMI measures are taken.

However, in the case of small-sized digital electronic devices, electronic components are mounted on a printed circuit board (PCB) at a high density. As a countermeasure against noise caused by the above-mentioned filter and the like, not only a mounting space is required but also consideration from the design stage It is not suitable as an urgent noise countermeasure for a product having a short product life.

For this reason, in recent years, in order to suppress inductive electromagnetic noise generated by active components, which are major noise sources in a circuit board of a small digital electronic device, a relatively thick soft magnetic compound sheet ) Are used.

The magnetic permeability of the composite magnetic sheet material is composed of the real magnetic permeability and the imaginary magnetic permeability. The suppression efficiency of the noise is suppressed as the imaginary magnetic permeability is increased in the electromagnetic noise frequency band to be suppressed, .

On the other hand, since the size of a digital electronic device such as a smart phone is becoming smaller, a product having such a thin composite magnetic body and having excellent electromagnetic wave suppressing effect is desired. In addition, with the trend toward miniaturization of electronic devices, it is required to reduce the thickness of composite magnetic sheet for noise countermeasures used in the above-mentioned sub-microwave band.

In addition, in the case of the composite magnetic sheet, the magnetic permeability loss is used to reduce the thickness of the composite magnetic sheet. The present magnetic material has a problem that it can not simultaneously satisfy the thin thickness and the conduction noise suppressing effect in a frequency band lower than about 10 to 100 MHz or higher.

Published Japanese Patent Application No. 2003-0022890 " Near infrared ray shielding film " Japanese Patent Application Laid-Open No. 10-2012-0102082 'Anti-reflection film'

An embodiment of the present invention provides a magnetic shield sheet capable of preventing scattering or loss of an amorphous ribbon without a protective film by braking the amorphous ribbon without bonding the protective film.

The magnetic shielding sheet according to an embodiment of the present invention includes at least one electromagnetic wave absorbing sheet having a plurality of braking amorphous ribbons; And an adhesive film adhered between the electromagnetic wave absorbing sheet, and the thickness of the magnetic shielding sheet may be 25 to 55 mu m.

The thickness of the electromagnetic wave absorbing sheet may be 10 to 25 mu m.

The thickness of the adhesive film may be 5 mu m.

The magnetic shield sheet may have a quality factor value of 80 or more with a frequency of 100 kHz to 300 kHz.

The Q value can be calculated by Equation (1).

[Equation 1]

Here, k is a constant, u 'is a first permeability, and u " is a second permeability.

The first permeability may be an actual permeability of the electromagnetic wave absorbing sheet.

The second magnetic permeability may be an imaginary magnetic permeability of the electromagnetic wave absorbing sheet.

The Q value before the braking treatment may be 10 to 50.

The amorphous piece may include a plurality of amorphous ribbons, and the amorphous ribbon may be composed of an Fe-based amorphous alloy, a Co-based amorphous alloy, or a nanocrystalline alloy.

The magnetic shield sheet according to an embodiment of the present invention can braking the amorphous ribbon without attaching a protective film to the magnetic shield sheet and preventing scattering or loss of the amorphous ribbon without a protective film.

In addition, since the amorphous ribbon is braked without attaching the protective film only by adjusting the thickness of the electric-field absorbing sheet and the adhesive film, an embodiment of the present invention can simplify the manufacturing process.

In addition, since the embodiment of the present invention has a high quality factor in the electromagnetic noise frequency band of 100 kHz to 300 kHz, it is possible to provide a magnetic shield sheet excellent in the electromagnetic wave absorption rate.

In addition, since the embodiment of the present invention is a thin film and the manufacturing process is simple, it is possible to realize an improvement in productivity and a reduction in manufacturing cost.

1 is a cross-sectional view illustrating a magnetic shield sheet according to an embodiment of the present invention.
FIG. 2 is a graph showing permeability per frequency of a magnetic shield sheet according to an embodiment of the present invention. FIG.
3A and 3B are graphs showing changes in the first magnetic permeability and the second magnetic permeability according to the frequency in the presence or absence of the braking process in the magnetic shield sheet according to the embodiment of the present invention.

The terms used in this specification will be briefly described and the present invention will be described in detail.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Also, in certain cases, there may be a term selected arbitrarily by the applicant, in which case the meaning thereof will be described in detail in the description of the corresponding invention. Therefore, the term used in the present invention should be defined based on the meaning of the term, not on the name of a simple term, but on the entire contents of the present invention.

When an element is referred to as "including" an element throughout the specification, it is to be understood that the element may include other elements as well, without departing from the spirit or scope of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification.

FIG. 1 is a cross-sectional view illustrating a magnetic shield sheet according to an embodiment of the present invention. FIG. 2 is a graph illustrating changes in a first magnetic permeability and a second magnetic permeability according to frequency in a magnetic shield sheet according to an embodiment of the present invention 3A and 3B are graphs showing changes in the first magnetic permeability and the second magnetic permeability according to the frequency in the presence or absence of the braking process in the magnetic shield sheet according to the embodiment of the present invention.

1, a magnetic shielding sheet 100 according to an embodiment of the present invention includes a first electromagnetic wave absorbing sheet 110, an adhesive film 130, and a second electromagnetic wave absorbing sheet 120, .

In general, the magnetic shielding sheet can be widely applied to electronic appliances including wireless charging of a smart phone, NFC (short-range wireless communication), MST (magnetic security transmission), and the like. Here, wireless charging can be classified into three methods: electromagnetic induction method, magnetic resonance method, and electromagnetic wave method. Most of the commercially available wireless charging technologies use electromagnetic induction. In this electromagnetic induction method, when a magnetic field is generated in a primary coil, which is a power transmitter, electromagnetic induction in which the magnetic field is induced in a secondary coil Technology. The electromagnetic induction method as the wireless charging technology has been standardized around the WPC (Wireless Power Consortium) and the PMA (Power Matters Alliance) called QI standard. WPC uses the power frequency band of 100 ~ 205kHz, and PMA uses 277 ~ 357kHz or 118 ~ 153kHz band. In addition, Near Field Communication (NFC) is one of radio frequency identification (RFID) technologies, and is a non-contact type short range wireless communication technology using a frequency band of 13.56 MHz. Tickets, and payments. In addition, Magnetic Secure Transmission (MST) is a technology designed to generate a magnetic field when a magnetic credit card is scratched, and card information is transmitted to a terminal. In this way, although the resonance frequencies are different for each function of wireless charging, NFC (short range wireless communication), MST (magnetic security transmission), etc. in which the magnetic shield sheet can be utilized, the magnetic shield sheet is not limited at a certain frequency, It can also have electromagnetic wave shielding function in frequency. However, according to the present invention, it is possible to provide a magnetic shield sheet having a high Q-value performance for a frequency of 100 to 300 kHz, which is a main frequency for application to a magnetic shielding sheet applicable to PMA in popularized WPC.

The first and second electromagnetic wave-absorbing sheets 110 and 120 are thin plate ribbons made of an amorphous alloy or a nano-crystal alloy. The ribbon of the amorphous alloy or the nano-crystal alloy is heat treated and then subjected to a braking treatment. Lt; / RTI >

The first and second electromagnetic wave absorbing sheets 110 and 120 are separated into a plurality of amorphous pieces by heat treating the bands of the amorphous alloy or the nano-crystal alloy and then braking the bumps. The thickness of the first and second electromagnetic wave absorbing sheets 110 and 120 is set to 10 to 25 占 퐉, and the use frequency band is 100 kHz to 300 kHz. At this time, when the thickness of the first and second electromagnetic wave absorbing sheets 110 and 120 exceeds 25 mu m, it is difficult to apply to a smartphone or the like which tends to be thinned. In addition, a plurality of amorphous pieces of the amorphous ribbon may have a size of several tens of micrometers to 3 mm or less. However, the present invention does not limit the size of a plurality of amorphous pieces.

The amorphous alloy may be an Fe-based or a Co-based amorphous alloy.

The Fe-Si-B alloy or the Fe-Si-B-Co alloy may be used as the Fe-based amorphous alloy, and the Co-Fe-Ni-Si- Cr-Si-B alloy can be used.

The Fe-Si-B alloy may have 70-90 atomic% of Fe and 10-30 atomic% of the sum of Si and B in the Fe-Si-B alloy. The higher the content of Fe and other metals, the higher the saturation magnetic flux density. However, when the content of Fe element is excessive, it is difficult to form amorphous. Therefore, in the present invention, the content of Fe is preferably 70-90 atomic%. When the sum of Si and B is in the range of 10-30 atomic%, the amorphous formability of the alloy is the most excellent. In order to prevent corrosion in such a basic composition, corrosion resistance elements such as Cr and Co may be added in an amount of 20 atomic% or less, and a small amount of other metal elements may be added as needed to impart different properties.

The nanocrystalline alloy may be Fe-Si-B-Cu-Nb alloy. In this case, the total amount of Fe is 73-80 at%, the sum of Si and B is 15-26 at%, the sum of Cu and Nb is 1-5 at%. An amorphous alloy having such a composition range in the form of a ribbon can be easily precipitated into nano-phase grains by a heat treatment to be described later.

The adhesive film 130 is a film to be adhered between the first and second electromagnetic wave absorbing sheets 110 and 120, and a PET (polyethylene terephthalate) film may be used. The adhesive film 130 is formed on both sides of the substrate with an adhesive layer. The adhesive film 130 may be of a type having a base material or an inorganic material type having no base material and formed of only an adhesive layer. The adhesive layer may be an acrylic adhesive, or other types of adhesives may be used.

The thickness of the adhesive film 130 may be 1 to 10 um, but most preferably it may be 5 um.

The first and second electromagnetic wave absorbing sheets 110 and 120 of the magnetic shield sheet 100 may each have a thickness of 10 to 25 탆. The thickness of the first and second electromagnetic wave absorbing sheets 110 and 120 is considered in consideration of the handling process after the heat treatment. As the thickness of the ribbon becomes thinner, the ribbon may be broken even in slight impact during handling after the heat treatment. To 25 m. The thickness of the first and second electromagnetic wave-absorbing sheets 110 and 120 may be an optimal thickness to prevent the fragments of the amorphous ribbon from scattering or being lost during the breaking process.

Accordingly, the thickness of the present magnetic shielding sheet 100 is 25 to 55 mu m, so that it is possible to manufacture a magnetic shield sheet having a large area and a large area. At this time, the thickness of the magnetic shielding sheet 110 is a total thickness of two sheets, that is, a case including the first and second electromagnetic wave absorbing sheets 110 and 120, and when two or more electromagnetic wave absorbing sheets are laminated, It is increased by the thickness of the electromagnetic wave absorbing sheet. That is, the thickness of the magnetic shielding sheet when three electromagnetic wave absorbing sheets are applied may be 40 to 85 탆. In other words, the thickness of the magnetic shielding sheet can be changed according to the number of the electromagnetic wave absorbing sheet to which the electromagnetic wave absorbing sheet is applied.

The magnetic shield sheet 100 manufactured through the above-described processes has improved Q factor as a quality coefficient value in a frequency range of 100 kHz to 300 kHz, and thus has a characteristic of excellent electromagnetic wave absorption rate. Here, the higher the Q value as the quality factor, the greater the electromagnetic wave absorbing effect.

On the other hand, the quality factor is calculated by the following equation (1).

Here, k is a constant, u 'is a first permeability, u' is a second permeability, and μ is a permeability.

The permeability is a coefficient that quantifies whether a magnetic flux for a certain material is passed. The permeability has a complex permeability, and the complex permeability is composed of a real permeability and an imaginary permeability.

At this time, the first magnetic permeability corresponds to the real permeability of the laminated magnetic shield sheet 100, and the second magnetic permeability corresponds to the imaginary permeability of the laminated magnetic shield sheet 100.

The real permeability is a component representing a magnetic property, and the imaginary permeability is a component representing a loss.

Therefore, according to Equation (1), the higher the value of u ', the higher the value of Q, and the higher the value of u', the lower the value of Q.

2, the magnetic shield sheet 100 according to the present invention has a Q (quality factor) value of 80 or more at a frequency of 100 kHz to 300 kHz, .

As shown in Table 1, the magnetic shield sheet 100 according to the present invention shows a remarkable difference in the Q value depending on the presence or absence of the braking process.

Process Property (@ 100kHz) L (uH) Q Non-Breaking 6.2 to 6.5 (single layer) 20-25 Breaking 5.9 to 6.2 (1-layer) > 75 6.55 to 6.8 (2-layer) > 80 7.2 to 7.3 (7-layer) > 115

In particular, the magnetic shield sheet 100 according to the present invention means a case where at least one electromagnetic wave absorbing sheet is stacked. As described above, the magnetic shielding sheet 100 according to the present invention is stacked on one or more sheets, and when one or more sheets are stacked, the Q value is remarkably high.

That is, as shown in FIG. 3A, the magnetic shielding sheet 100 which is not subjected to the braking process has a Q value of 10 to 50 in a state of a frequency of 100 kHz to 300 kHz. However, as shown in FIG. 3B, It can be seen that the shielding sheet 100 indicates that the Q value is 80 or more.

Accordingly, since the magnetic shield sheet 100 according to the embodiment of the present invention brakes the amorphous ribbon to increase the quality factor in the electromagnetic noise frequency band of 100 kHz to 300 kHz, the magnetic shield sheet 100, (100).

In addition, the magnetic shield sheet 100 according to an embodiment of the present invention can improve the quality factor and the electron absorption rate while braking the amorphous ribbon without attaching the protective film.

On the other hand, in the case of one electromagnetic wave absorbing sheet, the electromagnetic shielding sheet 100 has an adhesive film adhered to the lower part of the electromagnetic wave absorbing sheet to have a total thickness of 15 to 30 um and, when there are two electromagnetic wave absorbing sheets, When the film is attached and has a total thickness of 25 to 55 μm, an adhesive film is attached between the upper electromagnetic wave absorbing sheet and the intermediate electromagnetic wave absorbing sheet and between the intermediate electromagnetic wave absorbing sheet and the lower electromagnetic wave absorbing sheet when the electromagnetic wave absorbing sheet is three sheets, / RTI > to 85 < RTI ID = 0.0 > um. On the same principle, when the number of electromagnetic wave absorbing sheets is seven, the magnetic shielding sheet has a total thickness of 100 to 205 μm.

Accordingly, the thickness of the magnetic shield sheet 100 according to an embodiment of the present invention can be changed according to the number of the electromagnetic wave absorbing sheets, but it is preferable that the magnetic shield sheet 100 has a thickness of 15 to 400 um Do.

4 is a flowchart showing a method of manufacturing a magnetic shield sheet according to another embodiment of the present invention.

4, a method of manufacturing a magnetic shield sheet according to another embodiment of the present invention includes a first step (S10) of supplying first and second electromagnetic wave absorbing sheets (110, 120), a first step A second step S20 of heat treating the absorbent sheets 110 and 120 at 300 ° C. to 600 ° C. for 30 minutes to 4 hours to form an adhesive film 130 between the first and second electromagnetic wave absorbing sheets 110 and 120 A third step S30 of forming a magnetic shielding sheet 100 by attaching the magnetic shielding sheet 100, a fourth step S40 of braking the magnetic shielding sheet 100, a fifth step of laminating the magnetic shielding sheet 100, (S50) and a sixth step (S60) of cutting the laminated magnetic shielding sheet 100 to a predetermined size.

More specifically, the first step (S10) is a step of forming first and second electromagnetic wave absorbing sheets (110, 120) made of an amorphous alloy or a nanocrystalline alloy by rapid quenching (RSP) ). At this time, the first and second electromagnetic wave absorbing sheets 110 and 120 may each have a thickness of 10 to 25 um.

In the second step S20, the first and second electromagnetic wave absorbing sheets 110 and 120 are heat-treated at 300 to 600 ° C for 30 minutes to 4 hours so as to obtain a desired permeability. At this time, the annealing atmosphere may be annealed in an atmosphere, an atmosphere, or an oxidizing atmosphere or a nitrogen atmosphere depending on the Fe content of the amorphous ribbon or the nano-crystal alloy. If the heat treatment temperature is less than 300 ° C, the stress relief of the internal stress generated in the production of the magnetic sheet is not completely achieved, and unevenness of magnetic properties such as magnetic permeability is not solved, If the temperature exceeds 600 ° C, crystallization in the magnetic sheet rapidly occurs due to the superheating treatment, which results in a remarkably low permeability and does not exhibit a desired permeability. In general, a low heat treatment temperature requires a long treatment time, while a high heat treatment temperature means a short treatment time. If the heat treatment is applied to the first and second electromagnetic wave absorbing sheets 110 and 120 as described above, the brittleness of the first and second electromagnetic wave absorbing sheets 110 and 120 becomes strong, so that braking can be easily performed when the braking process is performed in a subsequent process.

In the third step S30, the adhesive film 130 is attached between the heat-treated first and second electromagnetic wave absorbing sheets 110 and 120 to form the magnetic shielding sheet 100. [ At this time, the thickness of the adhesive film may be 5 mu m.

Then, in the fourth step S40, the magnetic shielding sheet 100 is braked with the adhesive film 130 attached thereto.

The braking process is carried out in such a manner that the magnetic shielding sheet 100 in which the first electromagnetic wave absorbing sheet 110, the adhesive film 130 and the second electromagnetic wave absorbing sheet 120 are sequentially laminated is formed of a metal roller and a rubber roller A breaking device (not shown) is passed to separate the amorphous ribbon into a plurality of pieces. At this time, the plurality of separated pieces are kept separated by the adhesive film attached on the first and second electromagnetic wave absorbing sheets 110 and 120. In addition, since the plurality of pieces separated by the braking process are formed to have a size in the range of about several tens of m to 3 mm, the hysteresis loss can be removed by increasing the half-magnetic field, thereby increasing the uniformity of the magnetic permeability to the sheet.

In the fifth step S50, the magnetic shielding sheet 100 subjected to the braking process is filled with an adhesive in a gap between the pieces, and performs a lamination process for planarization, slimming and stabilization. At this time, the laminate apparatus (not shown) for the lamination process may be a roll press type or a hydraulic press type comprising two pressing rollers or pressing members. At this time, an adhesive capable of being deformed when pressurized at normal temperature is used, or a thermoplastic adhesive which is deformed when heat is applied can be used.

The braking device and the laminating device according to the present invention can be applied to any device that can perform the braking process or the laminating process.

According to the present invention, the amorphous ribbon can be braked without attaching a protective film to the magnetic shield sheet, and the thickness of the first electromagnetic wave absorbing sheet 110, the adhesive film 130, and the second electromagnetic wave absorbing sheet 120 Scattering and loss of the amorphous ribbon can be prevented by the adjustment and the laminating process, and the quality factor and the absorption rate of electromagnetic waves can be increased.

Finally, in the sixth step S60, the laminated magnetic shielding sheet 100 is cut to a desired length by the manufacturer. Accordingly, since the laminated magnetic shield sheet 100 is cut in the latter half of the process, the magnetic shield sheet of large area and large capacity can be manufactured, and the process efficiency can be further improved.

It is to be understood that the present invention is not limited to the above-described embodiment, but may be modified in various ways within the spirit and scope of the present invention as set forth in the following claims It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

100: magnetic field shielding sheet 110: first electromagnetic wave absorbing sheet
120: second electromagnetic wave absorbing sheet 130: adhesive film

Claims

Two electromagnetic wave absorbing sheets provided with a plurality of braked amorphous ribbons; And
A magnetic shielding sheet including an adhesive film adhered between the electromagnetic wave absorbing sheets,
Wherein the amorphous ribbon is an Fe-Si-B alloy having 70 to 90 at% of Fe, 10 to 30 at% of Si and B,
The thickness of the magnetic shielding sheet is 25 to 55 탆,
Wherein the magnetic shield sheet has a quality factor (Q) calculated by the following formula (1) at a frequency of 100 kHz of 80 or more,
Wherein the Q value before the braking treatment is in the range of 10 to 50.
[Equation 1]

Here, k is a constant, μ 'is a first permeability, which is the real permeability of the electromagnetic wave absorbing sheet, and μ "is a second permeability, which is an imaginary permeability of the electromagnetic wave absorbing sheet.

The method according to claim 1,
Wherein the electromagnetic wave absorbing sheet has a thickness of 10 to 25 mu m.

The method according to claim 1,
Wherein the adhesive film has a thickness of 5 mu m.

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