KR20170006237A - Heat radiation sheet for a wireless charging - Google Patents

Abstract

A heat radiation sheet for wireless charging is provided. According to an embodiment of the present invention, the heat radiation sheet for wireless charging to emit heat generated for wireless charging comprises: a heat radiation member; and a metal protection member attached to one surface of the heat radiation member with an adhesive, protecting the heat radiation member, and functioning as an auxiliary heat radiation member as well. Therefore, by replacing, with a metal material, a protection film attached to the one surface of the heat radiation sheet, a protection function from an external environment can be increased by increasing rigidity, and a heat radiation function is assigned to the protection function by using the metal material having heat conductivity, thereby increasing wireless charging efficiency by supplementing the heat radiation function of the heat radiation sheet.

Description

[0001] The present invention relates to a heat radiation sheet for wireless charging,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a heat-radiating sheet, and more particularly, to a heat-radiating sheet for wireless charging capable of effectively dissipating heat generated during wireless charging.

Recently, various functions such as Radio Frequency Identification (RFID), Near Field Communication (NFC), Wireless Charging (WPC) and interactive pen tablet have been added to mobile terminals including mobile phones and tablet PCs.

NFC is a non-contact type short-range wireless communication module that uses 13.56MHz frequency band as one of RFID tags, and it is a technology to transmit data between terminals at a distance of 10cm. NFC is widely used not only for mobile payments, but also for transferring travel information, transportation, and access control locks for goods information and visitors in supermarkets and general shops, as well as for file transfer.

In addition, recently announced by Google, 'Android Beam' included in the smart phone is a near-field wireless communication (NFC) -based short distance information transmission and reception function that not only allows mobile payment, but also photos, business cards, files, maps, To other phones.

Meanwhile, the portable terminal has a wireless charging function for wirelessly charging a built-in battery. The wireless charging includes a wireless power receiving module built in the portable terminal, a wireless power transmitting module for supplying power to the wireless power receiving module, Module.

At this time, the wireless power transmission module and the wireless power receiving module are provided with a heat dissipating member for discharging heat generated during wireless charging to the outside to increase the charging efficiency. For example, graphite (for example, graphite) having a high thermal conductivity is generally used as the heat dissipating member.

The heat dissipating member is provided with a protective film for protecting the heat dissipating member and preventing the heat dissipating member from being exposed to the outside. As such a protective film, a fluororesin-based film such as PET is commonly used.

However, when the conventional protective film is made of a fluororesin material such as PET, since the material itself has a weak strength, scratches are easily generated by an external impact, so that the protective film can not be satisfactorily performed as a protective film for protecting the heat radiation member.

In addition, in the case of a protective film made of a fluororesin such as PET, since the thermal conductivity is very low, there is a limit to perform only a simple protection function for protecting the heat radiation member.

Recently, electronic devices such as mobile phones have become smaller and thinner, and accordingly, the parts embedded in electronic devices have to be made smaller and smaller. In the case of a wireless power receiving module embedded in a mobile phone, the overall thickness is about 0.3T, and it will become thinner in the future.

In order to satisfy the characteristics required for such a very thin thickness, research and development have been progressing in various angles. As a part of this function, it is possible to support the functions of adjacent parts in cooperation with other adjacent parts through multifunctionality of the parts constituting the wireless power receiving module, that is, by changing the material or shape of the parts having only one unique function It is required to maintain the same thickness as the conventional product or to improve the characteristics while having a thinner thickness.

KR 10-2014-0147518 A

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a heat- Which is capable of enhancing the protection function of the heat-radiating sheet for wireless charging.

In addition, the present invention can replace a protective film attached to one surface of a heat-radiating sheet with a metal thin film having thermal conductivity to provide a heat radiation function in addition to a protective function, Another object is to provide a heat-radiating sheet.

In order to solve the above problems, the present invention provides a heat-radiating sheet for radiating heat generated during wireless charging, comprising: a heat dissipating member; And a metal protective member attached to one surface of the heat dissipating member with an adhesive to protect the heat dissipating member and functioning as an auxiliary heat dissipating member.

The heat-radiating sheet may be made of graphite or a plate-like member made of a metal having a thermal conductivity of 200 or more, preferably copper, aluminum, or the like.

In addition, the metal protecting member may be made of a copper foil or a copper foil containing a copper film.

In addition, the metal protecting member may be provided to have a thickness of 1/9 to 1/3 of the thickness of the heat-radiating sheet.

In addition, the metal protecting member may be formed with at least one slit having a predetermined length.

Also, the slits may be formed in a region corresponding to a wireless charging antenna disposed on one side of the heat-radiating sheet.

The slit may be formed in a direction perpendicular to a longitudinal direction of a pattern constituting the wireless charging antenna or perpendicular to a tangent of a pattern constituting the wireless charging antenna.

In addition, the adhesive may be an adhesive having thermal conductivity.

The metal protecting member may include a base material layer made of a metal material and a spin coating layer coated on at least one surface of the base material layer.

In addition, the spin coating layer may include at least one selected from ceramics and metal oxides.

According to the present invention, the protective film attached to one surface of the heat-radiating sheet is replaced with a metal material to increase the rigidity of the material itself, thereby preventing damage from external impacts, thereby enhancing the protection function against the external environment.

In addition, the present invention can replace the protective film attached to one surface of the heat-radiating sheet with a metal protecting member made of a metal having thermal conductivity to provide a heat-radiating function to the protective function, thereby enhancing the heat- There is an advantage.

In addition, the present invention has a slit-like structure for suppressing eddy current loss in a metal protecting member, and a coating layer for improving the emissivity is applied to improve the heat dissipation efficiency and the wireless charging efficiency.

1 is a cross-sectional view of a heat-radiating sheet for wireless charging according to an embodiment of the present invention,
Fig. 2 is a perspective view of Fig. 1,
FIG. 3 is a schematic view showing a disposition relationship between a slit and a wireless charging antenna when a slit is formed in a metal protecting member applied to a radiating sheet for wireless charging according to an embodiment of the present invention, wherein a) B) shows a case in which the wireless charging antenna is provided in a circular shape, Fig.
4A to 4D are views showing various shapes of slits formed in the metal protecting member applied to the heat radiating sheet for wireless charging according to an embodiment of the present invention,
5 is a view illustrating a case where a coating layer is formed on at least one surface of a metal protecting member, which is applied to a heat radiating sheet for wireless charging according to an embodiment of the present invention,
6 is a schematic view of a wireless power charging module to which a wireless heat radiating sheet according to an embodiment of the present invention is applied,
Fig. 7 is a sectional view of Fig. 6. Fig.

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 be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

The heat radiating sheet 100 for wireless charging according to an embodiment of the present invention is for discharging heat transmitted from a heat source to the outside. 6 and 7, of the wireless power charging module 1 including the antenna unit 10 and the shielding sheet 200, the shielding sheet 200 So that the efficiency of charging the wireless power charging module 1 can be increased by discharging the heat transferred from the antenna unit 10 and the shielding sheet 200 to the outside during wireless charging.

The wireless heat-radiating sheet 100 may have substantially the same area as the shielding sheet 200 and may be provided on one side of the shielding sheet 200 as a whole. In addition, the wireless heat-radiating sheet 100 may have a relatively smaller area than the shielding sheet 200 and may be partially provided on one surface of the shielding sheet 200, And may be disposed on one side of the shielding sheet 200.

Here, the wireless power charging module 1 may be a wireless power receiving module embedded in an electronic device such as a mobile phone, a PMP, a tablet, or the like, or a wireless power transmitting module for transmitting a wireless signal to the electronic device.

In addition, the antenna unit 10 may include at least one antenna that transmits or receives a radio signal in a predetermined frequency band, and may include a plurality of antennas 12, 13, and 14 that perform different roles . For example, the plurality of antennas 12, 13, and 14 may include at least one of a wireless charging antenna 12, an MST antenna 13, and an NFC antenna 14 operating in different frequency bands (See Figs. 3A, 3B and 6).

The plurality of antennas 12, 13, and 14 may be formed of a circular coil, a ellipse, or a rectangular flat coil wound in a clockwise or counterclockwise direction, or may be formed of a synthetic resin such as polyimide (PI) A conductor such as a copper foil may be patterned in a loop shape on at least one side of the circuit board 11 or may be formed of a loop-shaped metal pattern using conductive ink.

The shielding sheet 200 is made of a magnetic material so as to improve the characteristics of the antenna by shielding the magnetic field generated from the antenna unit 10 to increase the collection speed. For example, the shielding sheet 200 may be formed of a ribbon sheet of an amorphous alloy or a nano-crystal alloy, a ferrite sheet, a polymer sheet, or the like.

Here, the ferrite sheet may be a sintered ferrite sheet, and Ni-Zn ferrite or Mn-Zn ferrite may be used. In addition, the amorphous alloy or the nanocrystalline alloy may be a Fe-based or a Co-based magnetic alloy, and the amorphous alloy and the nanocrystalline alloy may include a three-element alloy or a five-element alloy. Here, the three-element alloy includes Fe, Si, and B, and the five-element alloy may include Fe, Si, B, Cu, and Nb.

It is also noted that the shielding sheet 200 may be formed in a laminated form of a plurality of amorphous alloy or nano-crystal alloy ribbon sheets. In addition, the shielding sheet 200 may be divided into a plurality of micro-pieces so as to suppress the generation of eddy current by increasing the resistance, and the plurality of micro-pieces may be entirely insulated or partially insulated among the neighboring micro- . At this time, the plurality of fine pieces may be formed to have a size of 1 to 3 mm, and each piece may be irregularly randomized.

The heat-radiating sheet 100 for wireless charging according to the present invention includes a heat dissipating member 110 and a metal protecting member 120, as shown in Figs.

The heat dissipating member 110 is for discharging the heat transferred from the heat source to the outside. For this purpose, the heat dissipating member 110 is made of a material having excellent thermal conductivity. For example, the heat dissipation member 110 may be formed of any one of copper, aluminum, and graphite, and may be formed of a mixture of two or more materials, and may have a thermal conductivity of 200 W / m · k or more.

At this time, the heat dissipating member 110 is formed of a plate-shaped member having a predetermined area so that the contact area with the heat source is enlarged to rapidly receive the heat generated from the heat source.

The metal protecting member 120 according to the present invention is formed to have a relatively thin thickness as compared with the heat dissipating member 110. That is, the metal protecting member 120 is provided to have a thickness substantially equal to that of a conventional protective film attached to at least one surface of the heat dissipating member 110 to protect the heat dissipating member 110, Thereby replacing the conventional protective film used for simply protecting the heat dissipating member 110.

The metal protection member 120 protects the heat dissipating member 110 as well as the heat dissipation of the heat dissipating member 110, unlike the conventional protective film, which simply protects the heat dissipating member 110 from the external environment. It also plays a complementary role to performance.

Here, the metal material constituting the metal protection member 120 may be in the form of copper, aluminum or a combination thereof having excellent thermal conductivity, or may be in the form of an alloy including at least one of copper and aluminum, The member 120 may be formed to have a thickness of 1/9 to 1/3 of the thickness of the heat radiation member 110.

For example, the metal protecting member 120 may be provided in the form of a copper foil or a thin copper foil such as a copper foil. The copper foil may have a thickness of 1/9 to 1 / 3 < / RTI >

This is because the metal protection member 120 made of a metal material is provided so as to have the same thickness or less as that of the conventional protection film to replace the conventional protection film, So that a function can be added.

For example, the heat dissipation member 110 may have a thickness of 17 μm, and the metal protection member 120 may have a thickness of 5 μm, so that the total thickness of the wireless heat dissipation sheet 100 is 40 μm or less As shown in FIG. However, it should be understood that the thickness of the heat dissipating member 110 and the metal protecting member 120 is not limited thereto, but may be formed to a very thin thickness, and it is possible to have various thicknesses depending on design conditions Leave.

Accordingly, the heat-radiating sheet 100 for wireless charging according to the present invention can be manufactured by a conventional method in which the metal protecting member 120 is made of a metal having a small thickness and is attached to one surface of the heat- A heat radiation function can be added to the protective function while having the same thickness or less than the film. Accordingly, the heat dissipation performance is complemented through the metal protection member 120 without increasing the overall thickness of the wireless heat dissipation sheet 100, thereby enhancing the overall heat dissipation performance.

In addition, since the metal protection member 120 according to the present invention is made of a metal material and the rigidity of the material itself is increased, rigidity is greatly increased as compared with a conventional protective film made of the same material as PET. Accordingly, unlike the conventional protective film, which easily causes damage such as scratches to an external impact, the heat dissipating member 110 is protected from an external impact through a metal material having high rigidity of the material itself, So that the heat dissipating member 110 can be more stably protected from the external environment.

For example, when the heat-radiating sheet 100 according to the present invention is applied to the wireless power charging module 1 including the antenna unit 10 and the shielding sheet 200 as shown in Figs. 6 and 7, When the wireless power receiving module is applied to a wireless power receiving module that is a type of the wireless power charging module 1, the heat generated in the antenna unit 10 can be transmitted without increasing the thickness of the wireless power receiving module, It is possible to increase the wireless charging efficiency.

The metal protecting member 120 is attached to one surface of the heat dissipating member 110 via the adhesive layer 130. At this time, at least one selected from the group consisting of polyethylene terephthalate (PET), polypropylene (PP), and polyterephthalate (PTFE) is included on the other surface of the heat dissipating member 110 for the purpose of simply protecting the heat dissipating member 110 A protective film 140 formed of a fluororesin-based film may be additionally provided. This is because when the heat-radiating sheet 100 for wireless charging according to the present invention is attached to one side of the shielding sheet 200, the protective film 140 is removed, So that it can be attached to the shielding sheet 200 through the adhesive layer 130 disposed between the heat dissipating members 110.

On the other hand, the adhesive layer 130 is provided to have thermal conductivity, thereby further enhancing the heat radiation effect. The adhesive layer 130 may be formed of a pressure sensitive adhesive containing a thermally conductive component or may be formed by applying a pressure sensitive adhesive containing a plate-like base material and a component having a thermal conductivity to at least one side of the base material.

For example, the pressure sensitive adhesive may be selected from acrylic, urethane and silicone pressure sensitive adhesives, and may be made of a thermally conductive pressure sensitive adhesive containing a thermally conductive filler for heat dissipation. The type of the thermally conductive filler included in the pressure-sensitive adhesive is not limited as long as it has thermal conductivity. That is, the thermally conductive filler may be a metal, an inorganic material, an organic material, or a mixture thereof. Specifically, the thermally conductive filler may be selected from the group consisting of Al, Ni, Cu, Sn, Zn, (W), iron (Fe), silver (Ag), and gold (Au); Calcium carbonate (CaCO _3), aluminum oxide (Al ₂ O _3), aluminum hydroxide (Al (OH) _3), silicon carbide (SiC); Inorganic powders such as boron nitride (BN) and aluminum nitride (AlN); As the carbon material, at least one selected from graphite, graphene, carbon nanotubes (CNT), and organic powders such as carbon nanofibers (CNF) can be used. Preferably, the thermally conductive filler includes at least one carbon material selected from the group consisting of graphite, graphene, carbon nanotube (CNT), carbon nanofiber (CNF), and the like. In addition, the thermally conductive filler can be mixed in an appropriate amount within a range that does not lower the adhesive force of the pressure-sensitive adhesive. For example, the thermally conductive filler may be included in an amount of 0.5 to 500 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive. If the content of the thermally conductive filler is less than 0.5 parts by weight, the thermal conductivity of the thermally conductive filler is insufficient due to its content. If the content of the thermally conductive filler is more than 500 parts by weight, the content of the adhesive may be relatively small. In addition, the thermally conductive adhesive may further include a dispersing agent for uniform dispersion of the thermally conductive filler, a crosslinking agent for controlling the adhesive property, and the like. In addition, the thermally conductive pressure-sensitive adhesive may further optionally contain an antioxidant, a defoaming agent, a thickener, a flame retardant, and the like in a range that does not adversely affect the adhesive strength.

5, the metal protecting member 120 'according to the present invention includes a substrate layer 123 made of a metal material for radiating heat and a coating layer (not shown) coated on at least one surface of the substrate layer 123 124). Here, as the coating layer 124, a metal oxide material including ceramic or carbon black having a nano-sized particle size may be used.

The coating layer 124 enhances the radiation efficiency of the metal protecting member 120 'by increasing the emissivity.

Also, the metal protecting member 120 may oxidize the surface of the metal material constituting the metal protecting member 120 through the blackening treatment to form an oxide film. For example, in the case of the metal material with the copper the oxide film may be an oxide, such as CuO and Cu ₂ O.

By this, it is possible to minimize cracking by preventing corrosion and improve adhesion and adhesion according to increase of surface area, and increase the emissivity of the material itself, thereby enhancing the heat radiation property without increasing the overall thickness.

In addition, the oxide layer formed on the surface of the metal layer acts as an insulating layer to increase the overall resistance value, thereby reducing the occurrence of eddy currents during wireless charging, thereby improving the charging efficiency. Here, the blackening treatment may be performed using chemicals, heat treatment, or plasma treatment.

1 to 4, at least one slit 122 having a predetermined length is formed through the metal protection member 120 to increase the resistance of the metal protection member 120 It is possible to suppress the occurrence of eddy currents during the wireless charging, thereby improving the charging efficiency.

Here, the slits 122 may be entirely or partly provided in the metal protection member 120. When the plurality of slits 122 are provided, the plurality of slits 122 are arranged in a predetermined pattern Or may be arranged in a random form.

At this time, the slit 122 is formed in a region corresponding to the antenna for wireless charging 12 among the antenna units disposed on one side of the shielding sheet 200, and the pattern constituting the antenna for wireless charging 12 And is formed in a vertical direction.

3A, when the wireless charging antenna 12 is formed in a rectangular pattern, the slit 122 is perpendicular to the longitudinal direction of the pattern of the wireless charging antenna 12 So as to have a predetermined length in the direction of the arrow.

3B, when the wireless charging antenna 12 is formed in a circular pattern, the slit 122 may extend in a direction perpendicular to the tangent line of the pattern constituting the wireless charging antenna 12 May be formed to have a predetermined length.

In addition, although not shown, if the wireless charging antenna 12 is provided in a form having both a straight section and a curved section, the slit formed in the straight section may be formed as a part of the wireless charging antenna 12 The slit formed in the curved section is formed to have a predetermined length in a direction perpendicular to the tangent line of the pattern constituting the wireless charging antenna 12 as shown in FIG. Respectively.

The slits 122 may be formed in various shapes as shown in FIGS. 4A to 4D. That is, the slit 122 may be provided in the form of a cutout 122a extending inwardly from the rim of the metal protection member 120 (see FIGS. 4C and 4D) (See Figs. 4A and 4B), and a cutout 122a and a through hole 122b may be provided in combination with each other (see Figs. 4A and 4B) Not shown).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1: wireless power charging module 10: antenna unit
11: circuit board 12: wireless charging antenna
13: Antenna for MST 14: Antenna for NFC
100: Heat-radiating sheet for wireless charging
110: heat radiation member 120, 120 ': metal protection member
122: slit 124: coating layer
130: adhesive layer 140: protective film
200: Shielding sheet

Claims (10)

A heat-radiating sheet for discharging heat generated during wireless charging,
A heat dissipating member; And
And a metal protective member attached to one surface of the heat dissipating member with an adhesive to protect the heat dissipating member and function as an auxiliary heat dissipating member. The method according to claim 1,
Wherein the heat-radiating sheet comprises any one selected from copper, aluminum, and graphite. The method according to claim 1,
Wherein the metal protecting member comprises a copper foil or a copper foil including a copper film. The method according to claim 1,
Wherein the metal protecting member is provided to have a thickness of 1/9 to 1/3 of the thickness of the heat-radiating sheet. The method according to claim 1,
Wherein the metal protecting member comprises at least one slit having a predetermined length. 6. The method of claim 5,
Wherein the slit is formed in a region corresponding to a wireless-charging antenna disposed on one side of the heat-radiating sheet. The method according to claim 6,
Wherein the slit is formed in a direction perpendicular to a longitudinal direction of a pattern constituting the wireless rechargeable antenna or perpendicular to a tangent of a pattern constituting the wireless rechargeable antenna. The method according to claim 1,
Wherein the adhesive is an adhesive having thermal conductivity. The method according to claim 1,
Wherein the metal protecting member comprises a base material layer of a metal material and a radiation coating layer coated on at least one side of the base material layer. 10. The method of claim 9,
Wherein the radiation coating layer comprises at least one selected from the group consisting of ceramic and metal oxide.

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