KR20190088955A - Receiving antennas and wireless power receiving apparatus comprising the same - Google Patents

Abstract

The present invention relates to a reception antenna to increase wireless power reception efficiency and a wireless power reception device including the same. According to one embodiment of the present invention, the reception antenna of a wireless power reception device wirelessly charging power comprises: a substrate; a first soft magnetic layer stacked on the substrate and made of a soft magnetic material; a first coil layer receiving electromagnetic energy irradiated from a wireless power transmission device, and wound in parallel to the soft magnetic layer; and a second coil layer electrically connected to the first coil layer and wound in parallel to the first coil layer wherein the directions of currents in the first and second coil layers are opposite to each other.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a receiving antenna and a wireless power receiving apparatus including the receiving antenna.

The present invention relates to wireless charging, and more particularly, to a receiving antenna for wireless charging and a wireless power receiving device including the same.

Wireless power transmission and reception technology is a technology for wirelessly supplying electric power to electronic devices. It can be applied not only to battery charging of portable terminals, but also to electric power supply for home electric appliances, electric power supply for electric vehicles and subways.

In order to increase the power transmission / reception efficiency, it is necessary to minimize the energy loss between the wireless power transmission apparatus and the wireless power reception apparatus. To this end, the transmit and receive antennas may be aligned within effective distances. Further, a soft magnetic material may be disposed around the transmission antenna and the reception antenna, so that the electromagnetic energy radiated by the transmission antenna can be focused in the direction of the reception antenna.

However, the soft magnetic material disposed around the receiving antenna is thin and has a high permeability in the planar direction. When the magnetization value of the soft magnetic material for the reception antenna is saturated, electromagnetic energy from the transmission antenna may leak. Accordingly, a method for increasing the transmission efficiency between the transmission antenna and the reception antenna is needed.

Korean Patent Publication No. 2013-0050633 (May 31, 2013) Korean Patent Publication No. 2008-0012782 (Feb. 12, 2008) Korean Patent Publication No. 2013-0048749 (Feb. U.S. Patent Application Publication No. 2012/0086281 (Apr. 12, 2012)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a structure of a receiving antenna for improving wireless power receiving efficiency of a wireless power receiving apparatus.

A receiving antenna of a wireless power receiving apparatus that wirelessly charges power according to an embodiment of the present invention includes a substrate, a first soft magnetic layer stacked on the substrate and made of a soft magnetic material, And a second coil layer electrically connected to the first coil layer and wound in parallel with the first coil layer, the first coil layer being wound in parallel with the soft magnetic layer, And a receiving coil whose current direction is opposite to that of the coil layer and the second coil layer.

And a support film formed between the first coil layer and the second coil layer. The first coil layer and the second coil layer may be connected to each other through a through hole formed in the support film.

At least a part of the first coil layer and the second coil layer may be embedded in the first soft magnetic layer.

And a second soft magnetic layer formed between the substrate and the first soft magnetic layer.

At least a portion of the first soft magnetic layer, the first coil layer, and the second coil layer may be embedded in a case of the wireless power receiving apparatus.

An adhesive layer of PET (polyethylene terephthalate) may be further included between the first coil layer and the second coil layer and the soft magnetic layer.

The first coil layer and the second coil layer are coil layers having the same shape, and the second coil layer may be reversed and stacked on the first coil layer.

A wireless power receiving apparatus for wirelessly charging electric power according to an embodiment of the present invention includes a substrate, a first soft magnetic layer stacked on the substrate and made of a soft magnetic material, A first coil layer wound in parallel with the soft magnetic layer and a second coil layer electrically connected to the first coil layer and wound in parallel with the first coil layer, A receiving coil connected to the receiving coil, for converting the electromagnetic energy to electric energy, and a storage unit for storing the electric energy.

According to the embodiment of the present invention, the electromagnetic energy focusing performance of the receiving antenna can be enhanced in the wireless power receiving apparatus, and the wireless power transmitting / receiving efficiency can be maximized. Particularly, it is possible to reduce the thickness of the receiving antenna and reduce the distance between the transmitting antenna and the receiving antenna, thereby obtaining improved power transmission efficiency.

As a result, it is possible to obtain a desired electromagnetic energy focusing effect even in a thin thickness, and it can be applied to a variety of electronic devices (for example, a TV, a portable terminal, a notebook PC, a tablet PC, etc.)

Further, since the electromagnetic energy focusing performance is excellent and the material cost is low, it can be applied to large-sized applications such as electric vehicles, subways, and electric trains.

Further, even if the wireless power transmission apparatus includes a permanent magnet, the influence of the permanent magnet can be absorbed, and high power transmission efficiency can be obtained. It is also compatible with the case where the wireless power transmission device does not include a permanent magnet.

Further, the manufacturing process is simple, and the burden of additional cost increase is small.

1 is a block diagram illustrating a wireless power transceiver system in accordance with an embodiment of the present invention.
FIG. 2 is a diagram showing a part of a wireless power transmission apparatus, and FIG. 3 is a diagram showing a part of a wireless power reception apparatus.
4 shows the power transmission efficiency between the wireless power transmission apparatus and the wireless power reception apparatus according to the thickness of the soft magnetic layer.
5 is a partial cross-sectional view of a wireless power transmission apparatus and a wireless power reception apparatus according to an embodiment of the present invention.
6 is an example of the first coil layer and the second coil layer.
FIG. 7 shows an example in which one coil layer is embedded in a soft magnetic layer according to an embodiment of the present invention, and FIG. 8 shows an example in which two coil layers are embedded in a soft magnetic layer according to another embodiment of the present invention.
Fig. 9 shows an example in which sheets of a soft magnetic material are laminated according to an embodiment of the present invention.
10 illustrates an example in which a receiving antenna is embedded in a rear case of a portable terminal according to an embodiment of the present invention.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms including ordinal, such as second, first, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

1 is a block diagram illustrating a wireless power transceiver system in accordance with an embodiment of the present invention.

Referring to FIG. 1, a wireless power transmission / reception system includes a wireless power transmission apparatus 100 and a wireless power reception apparatus 200. The wireless power transmission apparatus 100 applies electrical energy to a transmission antenna, and the transmission antenna converts electrical energy into electromagnetic energy and radiates it to the surroundings. The wireless power receiving apparatus 200 receives electromagnetic energy radiated from a transmitting antenna using a receiving antenna and converts the received electromagnetic energy into electric energy to charge the antenna.

Here, the wireless power transmission apparatus 100 is, for example, a transmission pad. The wireless power receiving apparatus 200 may be a portable terminal to which wireless power transmission / reception technology is applied, a household / personal electronic product, a transportation means, and the like. A mobile terminal to which the wireless power transmission / reception technology is applied, a household / personal electronic product, a transportation means, etc. may include only the wireless power receiving apparatus 200 or may include both the wireless power transmitting apparatus 100 and the wireless power receiving apparatus 200 Can be set.

Meanwhile, the wireless power receiving apparatus 200 may be configured to include a module having both a wireless power conversion (WPC) function and a near field communication (NFC) function. At this time, the wireless power receiving apparatus 200 may perform short-range wireless communication with the external apparatus 300 including the NFC module.

FIG. 2 is a diagram showing a part of a wireless power transmission apparatus, and FIG. 3 is a diagram showing a part of a wireless power reception apparatus.

2, the wireless power transmission apparatus 100 includes a transmission circuit (not shown), a soft magnetic core 110, a transmission antenna 120, and a permanent magnet 130.

The soft magnetic core 110 may be made of a soft magnetic material having a thickness of several mm. The transmission antenna 120 may be a transmission coil, and the permanent magnet 130 may be surrounded by a transmission antenna 120.

Referring to FIG. 3, the wireless power receiving apparatus 200 includes a receiving circuit (not shown), a soft magnetic layer 210, and a receiving coil 220. The soft magnetic layer 210 may be laminated on a substrate (not shown). The substrate may be composed of multiple layers of fixed sheets and may be bonded to the soft magnetic layer 210 to fix the soft magnetic layer 210.

The soft magnetic layer 210 concentrates the electromagnetic energy radiated from the transmitting antenna 120 of the wireless power transmission apparatus 100.

The soft magnetic layer 210 may be formed of a metal material or a ferrite material and the soft magnetic layer 210 may be formed in various forms such as a sintered body (pellet), a plate, a ribbon, a foil, . ≪ / RTI > As an example, the soft magnetic layer 210 may be in the form of a composite comprising a single metal or alloy powder flake comprising at least one of Fe, Co, Ni and a polymeric resin. As another example, the soft magnetic layer 210 may be an alloy ribbon, laminated ribbon, foil or film comprising at least one of Fe, Co, and Ni. As another example, the soft magnetic layer 210 may be a composite containing 90 wt% or more of FeSiCr flakes and 10 wt% or less of the polymer resin. As another example, the soft magnetic layer 210 may be a sheet, ribbon, foil or film containing Ni-Zn ferrite.

The receiving coil 220 is stacked on the soft magnetic layer 210. The receiving coil 220 may be a coiled surface wound in a direction parallel to the soft magnetic layer 210 on the soft magnetic layer 210. For example, a receiving antenna applied to a smart phone may be in the form of a spiral coil having an outer diameter of 50 mm or less and an inner diameter of 20 mm or more. The receiving circuit converts the electromagnetic energy received through the receiving coil 220 into electric energy, and charges the battery (not shown) with the converted electric energy.

Although not shown, a heat-radiating layer may be further included between the soft magnetic layer 210 and the receiving coil 220. In this specification, the soft magnetic layer 210 and the receive coil 220 may be referred to as receive antennas.

When the wireless power receiving apparatus 200 has the WPC function and the NFC function at the same time, the NFC coil 230 may be further stacked on the soft magnetic layer 210. The NFC coil 230 may be formed so as to surround the outside of the receiving coil 220.

Each of the reception coil 220 and the NFC coil 230 may be electrically connected to each other through a terminal 240.

4 shows the power transmission efficiency between the wireless power transmission apparatus and the wireless power reception apparatus according to the thickness of the soft magnetic layer.

Referring to FIG. 4, in the case of using a soft magnetic layer having a permeability of 50, the power transmission efficiency sharply increases until the thickness of the soft magnetic layer becomes 0.1 mm, but gradually increases after 0.2 mm. That is, when the thickness of the soft magnetic layer is 0.2 to 0.3 mm, most of the magnetic field shielding becomes possible. On the other hand, the loss energy of 25% is estimated to leak sideways through the gap (about 5 mm) between the transmitting and receiving antennas.

In the case where the wireless power transmission apparatus includes a permanent magnet and the distance between the transmission antenna and the reception antenna is 5 mm and the thickness of the soft magnetic layer in which the reception coil is stacked is 0.2 mm, And has a value of 0.75 to 0.8. In other words, it is common to obtain a transmission efficiency of 6-70% considering the loss of conduction and the loss of circuit.

Equation (1) represents the magnetic inductance coupling coefficient.

Where L _Rx is the inductance of the receiving antenna, L _Tx is the inductance of the transmitting antenna, M is the mutual inductance between the transmitting antenna and the receiving antenna, k is the inductive coupling coefficient, L _Rx is the inductance of the receiving antenna, to be.

L _Rx can be expressed by Equation (2), and L _Tx can be expressed by Equation (3) again.

Where L _Rx-self is the self-inductance of the receive antenna, L _Rx-mutual is the mutual inductance of the receive antenna, L _Tx-self is the self-inductance of the transmit antenna, L _{Tx- -mutual} is the mutual inductance of the transmitting antenna.

Referring to Equations 1 to 3, in order to increase k, the inductance of the reception antenna and the transmission antenna must be reduced. Since L _Rx-self and L _Tx-self are electrical characteristics determined by the length of the conductor, the inductance can be reduced according to the turn number of the antenna, but this also affects the mutual inductance between the transmitting antenna and the receiving antenna It is not effective. It is also possible to increase k by decreasing L _Tx-mutual , but this leads to a magnetic field weakening of the transmitting antenna. Accordingly, a method of decreasing L _Rx-mutual and increasing k can be considered.

According to one embodiment of the present invention, a pair of coil coil structures is used to reduce the mutual inductance of the receive antenna, i.e., L _Rx-mutual , and to increase k, i. _E. We want to increase efficiency.

5 is a partial cross-sectional view of a wireless power transmission apparatus and a wireless power reception apparatus according to an embodiment of the present invention.

Referring to FIG. 5, a receiving coil 220 is formed on one surface of the soft magnetic layer 210. The receiving coil 220 is illustrated as being formed below the soft magnetic layer 210 to show the relationship between the wireless power transmitting device and the wireless power receiving device. However, the receiving coil 220 may include a soft magnetic layer 210 and a receiving coil 220 The antenna structure can be inverted 180 degrees. Although not shown, an adhesive sheet may be further provided between the soft magnetic layer 210 and the receiving coil 220 to bond the soft magnetic layer 210 and the receiving coil 220 to each other. At this time, the receiving coil 220 may include at least two coil layers. The second coil layer 224 wound in parallel with the plane direction of the first coil layer 222 and the first coil layer 222 wound in parallel with the plane direction of the soft magnetic layer 210 . Between the first coil layer 222 and the second coil layer 224, a supporting film 510 for supporting both coil layers may be further laminated. The support film 510 may be made of, for example, polyimide (PI).

Here, the first coil layer 222 and the second coil layer 224 may be electrically connected. That is, one terminal of the first coil layer 222 and one terminal of the second coil layer 224 may be connected to each other. For example, one terminal of the first coil layer 222 and one terminal of the second coil layer 224 may be electrically connected through a through hole formed in the support film 510.

At this time, the first coil layer 222 and the second coil layer 224 have opposite current directions. Thus, the inductance can be canceled to reduce the _mutual inductance of the receiving antenna, i.e., L _Rx-mutual , and increase k, i.e., the magnetic inductive coupling coefficient.

According to one embodiment of the present invention, the first coil layer 222 and the second coil layer 224 have the same shape, and may be stacked by reversing 180 degrees with each other. 6 shows an example of the first coil layer and the second coil layer. 6A and 6B, the widths W1 and W2, the heights H1 and H2, and the number of turns of the first coil layer 222 and the second coil layer 224 are the same And the same coil layers can be inverted and overlapped with each other. That is, the second coil layer 224 having the same shape as the first coil layer 222 may be formed on the first coil layer 222 to cover the entire first coil layer 222. One of the two terminals 222-1 and 222-2 of the first coil layer 222 may be electrically connected to one of the two terminals 224-1 and 224-2 of the second coil layer 224 have.

Although not shown, an NFC coil 230 may be further formed on the soft magnetic layer 210 so as to surround the receiving coil 220. At this time, the NFC coil 230 may be formed of two coil layers electrically connected to each other like the receiving coil 220.

According to an embodiment of the present invention, at least one of the first coil layer 222 and the second coil layer 224 may be embedded in the soft magnetic layer 210.

FIG. 7 shows an example in which one coil layer is embedded in a soft magnetic layer according to an embodiment of the present invention, and FIG. 8 shows an example in which two coil layers are embedded in a soft magnetic layer according to another embodiment of the present invention.

7 and 8, one coil layer 222 or two coil layers 222 and 224 are embedded in the soft magnetic layer 210 in the reception antenna structure including a pair of coil layers. In order to facilitate embedding of the coil layers 222 and 224, the soft magnetic layer 210 may be made of a composite including a soft magnetic metal and a polymer resin.

Although not shown, an adhesive sheet of PET (polyethylene terephthalate) may be further included between the coil layers 222 and 224 and the soft magnetic layer 210. The adhesive sheet of the PET material can insulate the coil layers 222 and 224 from the soft magnetic layer 210.

When at least a portion of the coil layers 222 and 224 are embedded in the soft magnetic layer 210, the distance between the receiving coil and the transmitting coil is reduced, and the total thickness of the receiving antenna can be reduced. Accordingly, it is possible to reduce the leakage magnetic flux generated in the outside due to the gap between the receiving coil and the transmitting coil, increase the mutual inductance between the receiving coil and the transmitting coil, So that the power transmission efficiency can be increased.

Meanwhile, according to the embodiment of the present invention, a leakage magnetic flux can be minimized by laminating a sheet of soft magnetic material on the other surface of the soft magnetic layer 210.

Fig. 9 shows an example in which sheets of a soft magnetic material are laminated according to an embodiment of the present invention.

9, in the structure in which the coil layers 222 and 224 are embedded in the soft magnetic layer 210, the soft magnetic material sheet 212 is further joined to the other surface of the soft magnetic layer 210. [ In this specification, the soft magnetic layer 210 can be mixed with the first soft magnetic layer, and the sheet 212 of soft magnetic material can be mixed with the second soft magnetic layer.

Accordingly, the magnetic flux leaking out of the soft magnetic layer 210 due to the coil layers 222 and 224 can be prevented.

Although only two coil layers are embedded in the soft magnetic layer 210 in FIG. 9, one coil layer is embedded in the soft magnetic layer 210 or the two coil layers are not embedded in the soft magnetic layer 210, The sheet 212 of soft magnetic material may be further laminated.

Further, according to the embodiment of the present invention, the receiving antenna including the soft magnetic layer and the receiving coil may be embedded in the case of the wireless power receiving apparatus.

10 illustrates an example in which a receiving antenna is embedded in a rear case of a portable terminal according to an embodiment of the present invention.

10, in a structure in which two coil layers 222 and 224 are embedded in the soft magnetic layer 210 and the sheet 212 of soft magnetic material is joined together, the coil layers 222 and 224, the soft magnetic layer 210 and a sheet of soft magnetic material 212 are embedded in the rear case 900 of the portable terminal. For this purpose, a groove may be formed in the rear case 900 of the portable terminal, and then the groove and the reception antenna structure may be bonded.

Accordingly, the distance between the reception coil 220 and the transmission coil 120 can be reduced, and the transmission power efficiency can be increased.

10, two coil layers 222 and 224 are embedded in the soft magnetic layer 210 and the soft magnetic material sheet 212 is laminated. However, one coil layer is formed on the soft magnetic layer 210, Or a structure in which the two coil layers are not buried but is stacked on the soft magnetic layer 210 and the structure that does not include the sheet 212 of soft magnetic material can be embedded in the case.

Table 1 shows the results of measuring the power transmission efficiency according to various embodiments of the present invention.

No. rescue Transmission efficiency Soft magnetic layer thickness Receive coil thickness Other Landfill thickness Total thickness Comparative Example 1 1 layer receiving coil 61% 0.3mm 0.1mm * 1 Support film (20 탆) Adhesive sheet (30 탆) - 0.45mm Example 1 2-layer receiving coil 65% 0.3mm 0.1mm * 2 Support film (20 탆) Adhesive sheet (30 탆) - 0.55mm Example 2 Example 1 + 1 layer of landfill 65.6% 0.3mm 0.1mm * 2 Support film (20 탆) Adhesive sheet (30 탆) 0.1mm 0.45mm Example 3 Example 1 + 2-layer landfill 66.9% 0.3mm 0.1mm * 2 Adhesive sheet (60 탆) 0.2mm 0.36mm Example 4 Example 3+ Addition of sheet 68.2% 0.35mm 0.1mm * 2 Adhesive sheet (60 탆) 0.2mm 0.41mm Example 5 Example 4 < RTI ID = 0.0 > 68.2% 0.35mm 0.1mm * 2 Adhesive sheet (60 탆) 0.41mm -

Referring to Table 1, a single layer coil having a thickness of 0.1 mm is laminated on a soft magnetic layer made of a composite of a FeSiCr soft magnetic metal-polymer resin having a magnetic permeability of 50 and a thickness of 0.3 mm in Comparative Example 1, A general receiving antenna structure including a polyimide film having a thickness of 탆 was used. In Example 1, a different receiving antenna structure was used as in Comparative Example 1 except that a two-layer coil having a thickness of 0.1 mm was laminated on the soft magnetic layer and a supporting film was included between both coil layers.

In Embodiment 2, the other conditions are the same as those in Embodiment 1, and a reception antenna structure in which one coil layer is embedded in the soft magnetic layer is used. At this time, the coil was buried in a hot press process under the conditions of 150 DEG C and 100 kgf / cm < ^{2 &} gt ;.

In Example 3, the other conditions are the same as in Example 1 except that both coil layers are embedded in the soft magnetic layer, and a receiving antenna structure in which a 0.1 mm thick Cu foil is stamped between the both coil layers instead of the supporting film Respectively. At this time, the coil was buried in a hot press process under the conditions of 150 DEG C and 100 kgf / cm < ^{2 &} gt ;.

 In Example 4, the other condition was the same as that in Example 3, except that a receiving antenna structure in which a soft magnetic sheet having a thickness of 50 was further joined was used.

In Example 5, other conditions were the same as in Example 4 except that the receiving antenna structure was embedded in a hot-block process at 80 DEG C and 10 kgf / cm < ² >

Comparing Comparative Example 1 with Example 1, it can be seen that the power transmission efficiency is increased by 4%. Comparing the comparative example 1 with the example 2 and the comparative example 3, it can be seen that the transmission power efficiency can be increased by 4% or more while keeping the total thickness as it is or reducing it.

In comparison between Example 3 and Example 4, it can be seen that leakage flux can be prevented by the additional lamination of the soft magnetic sheet, and the power transmission efficiency can be maximized.

In addition, comparing Embodiment 3 and Embodiment 5, it can be seen that a thin thickness wireless power receiving apparatus can be realized because a separate thickness is not required for a receiving antenna while maximizing power transmission efficiency.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

200: Wireless power receiving device
210: soft magnetic layer
220: Receive coil
230: NFC coil
222: first coil layer
224: second coil layer
510: Support film

Claims (15)

A plurality of soft magnetic layers including a first soft magnetic layer and a second soft magnetic layer;
An adhesive layer disposed so as to face the first soft magnetic layer and the first surface;
A coil portion disposed on a second side of the adhesive layer that is opposite to the first side of the adhesive layer;
And a heat dissipation layer disposed adjacent to the plurality of soft magnetic layers
Wherein the plurality of soft magnetic layers include Fe,
Wherein the coil portion includes:
A wireless power receiving coil including a first coil layer contacting the second surface of the adhesive layer and a second coil layer disposed on the first coil layer; And
A third coil layer in contact with the second surface of the adhesive layer, and a fourth coil layer disposed on the third coil layer,
The third coil layer and the fourth coil layer are electrically connected to each other to surround the side surfaces of the first coil layer and the second coil layer,
Wherein the first coil layer includes a first connection portion formed in an inner region of the wireless charging receiving coil,
And the second coil layer includes a second connection portion formed in an inner region of the wireless charging receiving coil,
Wherein the first connection portion and the second connection portion are electrically connected to each other,
And a support film disposed between the first coil layer and the second coil layer. The method according to claim 1,
Wherein the support film includes a first through hole and a second through hole, and the first connection portion and the second connection portion are electrically connected through the first through hole. 3. The method of claim 2,
Wherein the first coil layer includes a third connection portion formed in an outer region of the wireless rechargeable receiving coil,
And the second coil layer includes a fourth connection portion formed in an outer region of the wireless charging receiving coil,
And the third connection part and the fourth connection part are electrically connected to each other. The method of claim 3,
And the third connection portion and the fourth connection portion are electrically connected through the second through hole. 5. The method of claim 4,
And the support film is disposed between the third coil layer and the fourth coil layer. 5. The method of claim 4,
Wherein the number of turns of the first coil layer and the number of turns of the second coil layer are the same. The method according to claim 6,
Wherein the third coil layer and the fourth coil layer have the same number of turns. 8. The method of claim 7,
Wherein the number of turns of the first coil layer is greater than the number of turns of the third coil layer. The method according to claim 1,
And the second soft magnetic layer is disposed between the first soft magnetic layer and the adhesive layer. 10. The method of claim 9,
And the heat dissipation layer is disposed between the second soft magnetic layer and the coil part. The method according to claim 1,
Wherein the wireless power receiving coil has an inner diameter of 20 mm or more and an outer diameter of 50 mm or less. The method according to claim 1,
Wherein the adhesive layer comprises polyimide. 5. The method of claim 4,
Wherein the first connection part, the second connection part, the third connection part and the fourth connection part are formed inside the NFC coil. The method according to claim 1,
Wherein a direction of a current of the first coil layer is opposite to a direction of a current of the second coil layer. The method according to claim 1,
Wherein the first coil layer and the third coil layer are coplanar.

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