KR101847876B1 - Method for manufacturing antenna of magnetic sheets - Google Patents

Abstract

The present invention relates to a method for forming an antenna coil on a magnetic sheet. Particularly, the present invention relates to a technology in which an antenna is integrated with the magnetic sheet by directly forming the antenna coil on the magnetic sheet instead of manufacturing an FPCB in which the antenna is already formed by mutually bonding with the magnetic sheet. The manufacturing method of an antenna integrated with a magnetic sheet comprises the following steps of: preparing the magnetic sheet composed by including a polymer resin and a soft metal powder; irradiating the magnetic sheet with a laser, and performing laser-etching so as to form a coil-shaped antenna pattern; and plating the coil-shaped antenna pattern.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing an integrated antenna in a magnetic sheet,

The present invention relates to a method of forming an antenna on a magnetic sheet, and in particular, unlike the prior art in which an FPCB in which an antenna coil is formed is bonded to a magnetic sheet, .

An alternating electromagnetic field emitted in a free space, that is, an electromagnetic wave propagates in the air, and when it meets another medium, part of the incident surface is reflected and disappears in the medium depending on the electrical characteristics (permeability, permittivity, electrical conductivity, It also permeates out of the medium. The magnetic sheet used as the electromagnetic shielding material is a magnetic material in which the magnetization direction of the material easily responds to the phase change of the external alternating electromagnetic field. In a phenomenon, a magnetic field distributed in space is drawn into the material, And forms a magnetic circuit having a flux. The magnetic permeability of the magnetic material is an index indicating the degree of raising the magnetic field line. When a soft magnetic material having a high magnetic permeability is used, the magnetic field distributed around the material is mostly drawn into the material to minimize the leakage magnetic field.

Such a magnetic sheet may be used as a single material such as a magnetic alloy or a ferrite sintered body, or may be formed by mixing a magnetic metal powder and / or a ferrite powder with an insulating resin, a rubber component, a ceramic or a non- It is used as a molded composite. In particular, a resin such as an insulating resin magnetic sheet and a magnetic sheet containing a magnetic component can have high magnetic properties as compared to a rubber-based magnetic sheet and have high magnetic properties due to such high density filling, It is advantageous in that it has good adhesion.

Recently, in order to realize miniaturization and slimness in a mobile device, circuit density and device integration have been achieved. However, if the metal surface of the battery pack and the printed circuit board are located near the antenna, it is difficult to exchange magnetic flux with the reader. In other words, when a change in magnetic flux occurs from the outside to a conductor such as a metal, an eddy current that prevents the magnetic flux change flows in the conductor, thereby generating a reaction magnetic flux. The magnetic flux received from the reader is lost by the reaction flux, and the antenna can not reach the antenna. To solve these problems, a magnetic sheet using a soft magnetic material is disposed on the back surface of the antenna. The magnetic sheet pre-shields the generation of electromagnetic waves or absorbs electromagnetic waves to suppress the interference of electromagnetic waves.

FIG. 1 is a view for explaining a conventional method of forming an NFC antenna on a magnetic sheet, and FIG. 2 is a view showing a stacked structure of an NFC antenna manufactured by the method of FIG. In the prior art, a flexible circuit board (FPCB) on which an antenna is formed and a ferrite sheet are covered with a double-sided tape. Therefore, in the prior art, there is a problem that the productivity is low and the angle at the time of attachment is wrong, and the adhesive force is low, so that the interlayer separation phenomenon occurs in which the flexible circuit board is easily separated from the ferrite sheet.

3 and 4 are views illustrating a conventional method of manufacturing an NFC antenna in a magnetic sheet of Patent Registration No. 10-1320873 and a stacked structure of the NFC antenna manufactured. Patent Publication No. 10-1320873 discloses an NFC antenna manufacturing method in which a flexible copper-clad laminated film is laminated so that a bonding sheet is positioned between a flexible copper-clad laminated film and a ferrite sheet, a coverlay is laminated so as to contact one surface of the flexible copper- And performing a hot press process so that the joined soft copper foil laminated film, the ferrite sheet and the cover lay are finally bonded together.

1 to 4, there is a problem that a magnetic sheet such as a ferrite sheet and an antenna layer (FPCB) must be separately prepared and adhered (or laminated), and problems such as adhesion problems, productivity problems, Still remains.

Patent Registration No. 10-1320873

It is an object of the present invention to provide a method of integrally forming an antenna on a magnetic sheet without forming a magnetic sheet and an antenna layer by bonding in forming an antenna on a magnetic sheet.

In particular, unlike the prior art in which an antenna is formed by bonding an FPCB having an antenna and a magnetic sheet, the present invention provides a method of manufacturing a magnetic sheet in which antennas are integrally formed without using a separate FPCB The purpose.

In particular, it is an object of the present invention to provide a method of integrally forming an antenna on a magnetic sheet through a plating method.

The present invention provides a method of manufacturing a magnetic sheet, comprising: preparing a magnetic sheet comprising a polymer resin and a soft magnetic metal powder; Irradiating the magnetic sheet with a laser to form a coil-shaped antenna pattern; And a step of plating the antenna pattern of the coil shape. The present invention also provides a method of manufacturing an antenna integrated with a magnetic sheet.

Particularly, the polymer resin is preferably selected from the group consisting of chlorinated polyethylene, ethylene propylene dimethyl, silicone rubber, acrylic resin, amide resin, epoxy resin, phenol resin, polyester resin, polyethylene resin, polypropylene resin, PVC resin, Rubber, polyvinyl butyral resin, polyurethane resin, nitrile-butadiene rubber, styrene-butadiene rubber and the like can be used.

In particular, the soft magnetic metal powder may be at least one selected from the group consisting of Sandstorm, Fe-Si-Cr, Amorphous (Fe-Si-B), Nanocrystalline (Fe- Permalloy and the like are possible.

In particular, the antenna pattern irradiated with the laser is preferably subjected to laser etching so that the polymer resin is burned to expose the soft magnetic metal powder.

In particular, the antenna may be an NFC (Near Field Communication) antenna, an MST (Magnetic Secure Transmission) antenna, or a WPT (Wireless Power Transmission) antenna.

Particularly, the plating is characterized by being Cu plating.

In particular, the plating may be direct plating of Cu or plating through a Pd-Sn catalyst.

Unlike the conventional method in which the FPCB having the antenna coil is formed by bonding with the magnetic sheet, the antenna coil is integrally formed directly on the magnetic sheet, The productivity is improved as compared with the method of joining the separate antenna layer of the prior art and the problem of peeling of the antenna is solved because the antenna is formed by plating on the magnetic sheet and it is necessary to attach the antenna layer to the magnetic sheet There is no possibility of a problem of defective due to twisting of the bonding position.

According to the present invention, the magnetic sheet having the integrated antenna formed thereon can be used as an RFID antenna or the like. Since the magnetic sheet can be made thinner than the conventional RFID antenna manufactured by bonding the magnetic sheet with the FPCB formed with the antenna coil, Thereby improving the recognition distance and reducing the manufacturing cost.

Further, in the method of the present invention, the irregularities are formed on the magnetic sheet by laser irradiation, and the conductive metal is plated on the irregularities, so that the antennas are integrally manufactured. Therefore, An adhesion improving effect can be obtained.

1 and 2 are views for explaining a method of forming an antenna on a magnetic sheet of the prior art and a structure of an RFID antenna manufactured by the method.
3 and 4 are views for explaining a method of forming an antenna on a magnetic sheet of the prior art Patent Registration No. 10-1320873 and a structure of an RFID antenna manufactured by the method.
5 is a flowchart illustrating the method of the present invention.
Figure 6 is a diagram illustrating the method of the present invention.
7 is a comparative diagram of a magnetic sheet having an antenna manufactured by a conventional method and a magnetic sheet integrally formed with an antenna manufactured by the method of the present invention.
8 is a photograph of a magnetic sheet in which antennas manufactured by the method of the present invention are integrally formed.

The present invention relates to a method of forming an antenna on a magnetic sheet in which a polymer resin and a soft magnetic metal powder are mixed. Hereinafter, the term "magnetic sheet" in the present invention is used as an abbreviation used to mean a magnetic sheet of a mixture of a resin and a soft magnetic metal powder as described above.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Figure 5 is a flow chart of the method of the present invention. The present invention provides a method of manufacturing a magnetic sheet, comprising: preparing a magnetic sheet comprising a polymer resin and a soft magnetic metal powder; Irradiating the magnetic sheet with a laser to form a coil-shaped antenna pattern; And a step of plating the antenna pattern of the coil shape. The present invention also provides a method of manufacturing an antenna integrated with a magnetic sheet.

Hereinafter, each step will be described in more detail.

Magnetic sheet preparation

The magnetic sheet used in the present invention comprises a polymer resin and a soft magnetic metal powder.

Examples of the polymer resin include chlorinated polyethylene, ethylene propylene dimethyl, silicone rubber, acrylic resin, amide resin, epoxy resin, phenol resin, polyester resin, polyethylene resin, ethylene-propylene rubber, Polyvinyl butyral resin, polyurethane resin, nitrile-butadiene rubber and the like can be used, and the present invention is not limited to a specific polymer resin.

The soft magnetic metal powder may be a soft magnetic metal powder in the form of a metal and a metal alloy rather than an oxide soft magnetic material. The soft magnetic metal powder may be at least one selected from the group consisting of Sandstorm, Fe-Si-Cr, amorphous (Fe-Si-B), nano-cristalline (Fe-Nb-Si-Cu-B), Fe-Si, permalloy, The same conductive magnetic powder can be used, but is not limited thereto.

 When the soft magnetic metal powder is an oxide such as ferrite, the antenna can not be formed because it can not serve as a metal seed for plating at the time of copper plating. That is, by using the soft magnetic metal powder of a pure metal or an alloy, which is not a metal oxide, the soft magnetic metal powder in the present invention serves as a metal seed to form a plating layer during plating.

That is, in the present invention, the term "soft magnetic metal powder" is used to mean a soft magnetic metal magnetic body made of a metal and an alloy of a metal other than the soft magnetic material in the form of metal oxide such as ferrite.

Laser patterning step

The magnetic sheet is patterned into a coil shape using a desired antenna pattern, for example, a laser etching method. The polymer resin in the portion irradiated with the laser is removed by burning and only the soft magnetic metal powder is left in the etching process so that only the magnetic material is exposed in the portion irradiated with the laser according to the antenna pattern, So that plating is performed.

Various known techniques for making an antenna pattern by laser patterning have been disclosed. For example, various known techniques such as Patent Registration No. 10-1213958, Patent Registration No. 10-1213958, and Patent Registration No. 10-1356356 A detailed description of a technique for manufacturing an antenna pattern using a laser will be omitted.

The grooves of a certain depth may be formed to conform to the shape of the antenna by laser patterning, and the depth of the grooves will be changed by the laser irradiation time, the laser intensity, and the like.

6 shows an embodiment in which the antenna pattern 51 is engraved on both the upper and lower surfaces of the magnetic sheet 50 and the antenna pattern 51 is formed on either or both of the upper and lower surfaces of the magnetic sheet 50 by laser irradiation . Here, the depth of the antenna pattern 51 by laser etching can be controlled to various depths from nm to μm.

Plating step

The soft magnetic metal powder is exposed in the groove-shaped antenna pattern 51 according to the laser patterning. The soft magnetic metal powder thus exposed serves as a metal seed for plating, and a conductive metal, for example, Cu The antenna 60 is completed. In the portion other than the antenna pattern 51, the soft magnetic metal powder serving as a seed during plating is not exposed, so that Cu plating is not performed.

The Cu plating can be performed by a known method. The Cu may be plated through a catalyst treatment using a Pd-Sn compound. Alternatively, Cu may be directly plated on the magnetic sheet without the Pd-Sn catalyst. As such a plating, a known electrolytic plating and / or electroless plating method may be used.

An antenna manufactured by the method of the present invention can be used for various purposes, but it can be used as an NFC (Near Field Communication) antenna, an MST (Magnetic Secure Transmission) antenna, or a WPT (Wireless Power Transmission) antenna.

Particularly, in the present invention, since the antenna is integrally formed by plating the conductive metal on the concavo-convex portion formed by the laser irradiation, it is possible to obtain the effect of improving the selective plating performance and the adhesion of the plating due to such unevenness.

Comparison with a conventional magnetic sheet on which an antenna is formed

The difference between the magnetic sheet 100 of the present invention and the conventional magnetic sheet 100 ', which are finally manufactured through the above-described process, will be described with reference to FIG.

7 is a cross-sectional view of a magnetic sheet 100 'having an antenna according to a conventional method. The magnetic sheet 50 and the FPCB 70 on which the antenna 60 is formed are bonded to each other. The antenna 60 is integrally formed on the magnetic sheet 50 and the FPCB 70 on which the antenna is formed is not required. Therefore, the magnetic sheet 100 formed with the antenna coil manufactured by the method of the present invention does not have a process of joining the sheets unlike the prior art, so there is a problem of adhesive force, productivity, I can solve all the problems.

8 is a photograph of a magnetic sheet having an antenna coil manufactured by the method of the present invention. The magnetic sheet was produced by mixing a sandstock and a polyurethane resin as a soft magnetic metal powder. After patterning the fiber for forming an antenna pattern, Cu plating was performed. Cu plating was completed by plating with a total thickness of 35 μm through first electroless plating (formalin + caustic soda + copper sulfate + stabilizer, 30 min) and secondary electrolytic plating (copper sulfate + sulfuric acid + hydrochloric acid + additive, 30 min) .

50: magnetic sheet
51: Antenna pattern
60: antenna
70: FPCB
100 ': A magnetic sheet formed with an antenna manufactured by a conventional method
100: The magnetic sheet with the antenna of the present invention formed integrally

Claims (7)

Preparing a magnetic sheet comprising a polymer resin and a soft magnetic metal powder;
Irradiating the magnetic sheet with a laser to form a coil-shaped antenna pattern; And
And plating the coil-shaped antenna pattern,
Wherein the antenna pattern irradiated with the laser is subjected to laser etching so that the polymer resin is burned to expose the soft magnetic metal powder.
The resin composition according to claim 1, wherein the polymer resin is selected from the group consisting of chlorinated polyethylene, ethylene propylene dimethyl, silicone rubber, acrylic resin, amide resin, epoxy resin, phenol resin, polyester resin, polyethylene resin, polypropylene resin, Wherein the magnetic sheet is an ethylene-propylene rubber, a polyvinyl butyral resin, a polyurethane resin, a nitrile-butadiene rubber or a styrene-butadiene rubber.
The soft magnetic metal powder according to claim 1, wherein the soft magnetic metal powder is at least one selected from the group consisting of Sandsted, Fe-Si-Cr, Amorphous (Fe-Si-B), Nanocrystalline (Fe- Or Mo-permalloy. ≪ RTI ID = 0.0 > 11. < / RTI >
delete The method of claim 1, wherein the antenna is an NFC (Near Field Communication) antenna, a MST (Magnetic Secure Transmission) antenna, or a WPT (Wireless Power Transmission) antenna.
The method of manufacturing an integrated antenna according to claim 1, wherein the plating is Cu plating.
The method of manufacturing an integrated antenna according to claim 6, wherein the plating is direct plating of Cu or plating through a Pd-Sn catalyst.

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