KR102201600B1 - Heat radiation sheet for a wireless charging - Google Patents

Abstract

A heat dissipation sheet for wireless charging is provided. The heat dissipation sheet for wireless charging according to an exemplary embodiment of the present invention is for dissipating heat generated during wireless charging, comprising: a heat dissipating member; And a metal protection member attached to one surface of the heat dissipation member via an adhesive having thermal conductivity to protect the heat dissipation member and function as an auxiliary heat dissipation member, wherein the metal protection member includes one side of the heat dissipation member. It provides a heat dissipation sheet for wireless charging including at least one slit formed to have a predetermined length in a region corresponding to the antenna for wireless charging disposed on. According to this, by replacing the protective film attached to one side of the heat dissipation sheet with a metal material, it is possible to increase the stiffness to increase the protection function from the external environment, and by adding a heat dissipation function to the protection function by using a metal material having thermal conductivity. There is an advantage of improving the wireless charging efficiency by supplementing the heat dissipation performance of the heat dissipation sheet.

Description

Heat radiation sheet for a wireless charging}

The present invention relates to a heat radiation sheet, and more particularly, to a heat radiation sheet for wireless charging capable of effectively dissipating heat generated during wireless charging.

Recently, various functions such as radio frequency identification (RFID), short-range wireless communication (NFC), wireless charging (WPC), and interactive pen tablets have been added to portable terminals including mobile phones and tablet PCs.

NFC is one of RFID, an electronic tag, and refers to a technology that transmits data between terminals at a close distance of 10cm with a non-contact short-range wireless communication module using a 13.56MHz frequency band. NFC is not only a mobile payment method, but also a file transmission method. It is widely used in supermarkets or general stores to transmit product information or travel information for visitors, traffic, and access control locks.

In addition, the'Android Beam' installed in a smartphone recently announced by Google is a short-range wireless communication (NFC)-based short-range information transmission/reception function, as well as mobile payments, photos, business cards, files, maps, websites, etc. It provides a function to transfer to another phone.

On the other hand, the portable terminal is equipped with a wireless charging function for wirelessly charging the built-in battery. Such wireless charging includes a wireless power receiving module built in the portable terminal and a wireless power transmission supplying power to the wireless power receiving module. Made by modules.

At this time, the wireless power transmitting module and the wireless power receiving module are provided with a heat dissipating member for increasing charging efficiency by dissipating heat generated during wireless charging to the outside. For example, graphite (eg, graphite) having good thermal conductivity is commonly used as the heat dissipating member.

A protective film is attached to the heat dissipating member to protect the heat dissipating member and prevent external exposure of the heat dissipating member. As such a protective film, a fluororesin film such as PET is commonly used.

However, when the conventional protective film is made of a fluororesin-based material such as PET, the strength of the material itself is weak and scratches are easily generated by external impact, and thus it cannot smoothly function as a protective film for protecting the heat dissipating 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 limitation in performing only a simple protective function to protect the heat dissipating member.

Recently, electronic devices such as mobile phones have become light, thin, short and small, and accordingly, components built into electronic devices must also be light, thin, short and small. In the case of the wireless power receiving module built into the mobile phone, the overall thickness is manufactured to about 0.3T, and it will be even thinner in the future.

Research and development are being conducted from various angles in order to satisfy the characteristics required at such a very thin thickness. As part of this, it is possible to cooperate with other adjacent parts to assist the functions of adjacent parts through multifunctionalization of each part constituting the wireless power receiving module, that is, changing the material or shape of parts that had only one unique function. There is a need for a way to improve characteristics while maintaining the same thickness as the existing product or having a thinner thickness by adding

KR 10-2014-0147518 A

The present invention was devised in consideration of the above points, and by replacing the protective film attached to the exposed surface of the heat dissipation sheet with a metal material, it increases the stiffness of the material itself, thereby preventing it from being easily damaged by an external impact. Its purpose is to provide a heat dissipation sheet for wireless charging that can increase the protection function of the device.

In addition, the present invention replaces the protective film attached to one surface of the heat dissipation sheet with a metal thin film having thermal conductivity, and adds a heat dissipation function in addition to the protective function, so that wireless charging capable of performing various functions simultaneously through one member. There is another purpose to provide a heat dissipation sheet for use.

In order to solve the above problem, the present invention is for dissipating heat generated during wireless charging, comprising: a heat dissipating member; And a metal protection member attached to one surface of the heat dissipation member via an adhesive having thermal conductivity to protect the heat dissipation member and function as an auxiliary heat dissipation member, wherein the metal protection member includes one side of the heat dissipation member. It provides a heat dissipation sheet for wireless charging including at least one slit formed to have a predetermined length in a region corresponding to the antenna for wireless charging disposed on.

In addition, the heat dissipation member may be made of graphite material.

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

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

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Further, 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 line of a pattern constituting the wireless charging antenna.

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

In addition, the metal protection member may include a base layer made of a metal material and a coating layer coated on at least one surface of the base layer.

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

According to the present invention, by replacing the protective film attached to one surface of the heat dissipation sheet with a metal material, the rigidity of the material itself is increased, thereby preventing it from being easily damaged from an external shock, thereby enhancing a protective function from the external environment.

In addition, in the present invention, by replacing the protective film attached to one side of the heat dissipation sheet with a metal protective member of a metal material having thermal conductivity, the heat dissipation function of the heat dissipation sheet is supplemented by adding a heat dissipation function to the protective function, thereby increasing wireless charging efficiency There is an advantage.

In addition, the present invention applies a structure such as a slit for suppressing eddy current loss to a metal protection member and a coating layer for improving emissivity, thereby improving heat dissipation efficiency and further increasing wireless charging efficiency.

1 is a cross-sectional view showing a heat dissipation sheet for wireless charging according to an embodiment of the present invention,
Figure 2 is a perspective view of Figure 1,
3A and 3B are schematic diagrams showing an arrangement relationship between a slit and an antenna for wireless charging when a slit is formed in a metal protection member applied to a heat dissipation sheet for wireless charging according to an embodiment of the present invention, and FIG. 3A is The charging antenna is provided in a square shape, and FIG. 3B is a view showing a case where the wireless charging antenna is provided in a circular shape.
4A to 4D are views showing various forms of slits formed in a metal protection member applied to a heat dissipation sheet for wireless charging according to an embodiment of the present invention;
5 is a view showing a case in which a coating layer is formed on at least one surface of the metal protection member as a metal protection member applied to the heat dissipation 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 heat dissipation sheet for wireless charging is applied according to an embodiment of the present invention,
7 is a cross-sectional view of FIG. 6.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the present invention. The present invention may be implemented in various different forms, and is not limited to the embodiments described herein. In the drawings, parts not related to the description are omitted in order to clearly describe the present invention, and the same reference numerals are added to the same or similar components throughout the specification.

The heat dissipation 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. For example, the heat dissipation sheet 100 for wireless charging is the shielding sheet 200 of the wireless power charging module 1 including an antenna unit 10 and a shielding sheet 200 as shown in FIGS. 6 and 7. ), it is possible to increase the charging efficiency of the wireless power charging module 1 by discharging heat transferred from the antenna unit 10 and the shielding sheet 200 to the outside during wireless charging.

The heat dissipation sheet 100 for wireless charging as described above may be provided to have approximately the same area as the shielding sheet 200 and may be entirely provided on one surface of the shielding sheet 200. In addition, the heat dissipation sheet 100 for wireless charging may be provided to have a relatively smaller area than the shielding sheet 200 and may be partially provided on one side of the shielding sheet 200, or may be provided in a plurality of It should be noted that it 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 that transmits a wireless signal to the electronic device.

In addition, the antenna unit 10 includes at least one antenna for transmitting or receiving a radio signal in a predetermined frequency band, and may be composed of a plurality of antennas 12, 13, and 14 performing different roles. . As an example, the plurality of antennas (12, 13, 14) may include any one or more of a wireless charging antenna (12), MST antenna (13) and NFC antenna (14) operating in different frequency bands. Can (see Figs. 3A, 3B and 6).

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

Meanwhile, the shielding sheet 200 is made of a material having magnetic properties to improve the characteristics of the antenna by shielding the magnetic field generated by the antenna unit 10 and increasing the focusing speed. For example, the shielding sheet 200 may be a ribbon sheet, a ferrite sheet, or a polymer sheet of an amorphous alloy or a nano-crystal alloy.

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 Co-based magnetic alloy may be used, 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.

In addition, it should be noted that the shielding sheet 200 may be formed in a form in which ribbon sheets of a plurality of amorphous alloys or nanocrystalline alloys are stacked. In addition, the shielding sheet 200 may be separately formed into a plurality of fine pieces to increase resistance to suppress the generation of eddy currents, and the plurality of fine pieces may be entirely insulated or partially insulated between neighboring fine pieces. It can be provided. At this time, the plurality of fine pieces may be provided in a size of 1 μm to 3 mm, and each piece may be formed randomly in an irregular shape.

The heat dissipation sheet 100 for wireless charging according to the present invention includes a heat dissipation member 110 and a metal protection member 120 as shown in FIGS. 1 and 2.

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

In this case, the heat dissipation member 110 is made of a plate-shaped member having a predetermined area so as to rapidly receive heat generated from the heat source by increasing the contact area with the heat source.

The metal protection member 120 according to the present invention is provided to have a relatively thin thickness compared to the heat dissipation member 110. That is, the metal protection member 120 is provided to have approximately the same thickness as a conventional protective film attached to at least one surface of the heat radiation member 110 to protect the heat radiation member 110. By being attached to one side, it simply replaces the conventional protective film used to protect the heat dissipation member 110.

Accordingly, the metal protection member 120 serves to protect the heat dissipation member 110 and heat dissipation of the heat dissipation member 110 unlike the conventional protective film that simply protects the heat dissipation member 110 from the external environment. It plays the role of complementing the performance at the same time.

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, may be an alloy form including at least one of copper or aluminum, and the metal protection The member 120 may be provided to have a thickness of 1/9 to 1/3 of the thickness of the heat dissipating member 110.

For example, the metal protection member 120 may be provided in the form of a copper foil having a thin thickness such as a copper foil or a copper film, and the copper foil is 1/9 to 1/ with respect to the thickness of the heat dissipating member 110 It may be provided to have a thickness of 3.

This is because the metal protection member 120 made of a metal material is provided to have the same thickness as or less than that of the conventional protective film, and by replacing the conventional protective film, heat dissipation to the protection function without increasing the overall thickness of the heat dissipation sheet. It is to be able to add functions.

For example, the heat dissipation member 110 may have a thickness of 17 μm, and the metal protection member 120 is provided to have a thickness of 5 μm, so that the total thickness of the heat dissipation sheet 100 for wireless charging is 40 μm or less. It may be provided to have a thickness of. However, it should be understood that the thickness of the heat dissipation member 110 and the metal protection member 120 is not limited thereto, and may be configured to have a very thin thickness, and it is found that it may have various thicknesses according to design conditions. Put.

Accordingly, in the heat dissipation sheet 100 for wireless charging according to the present invention, the metal protection member 120 is made of a metal material having a thin thickness and is attached to one side of the heat dissipation member 110, thereby simply performing a protection function. The heat dissipation function may be added to the protective function while having the same thickness as the film or less than that of the film. Accordingly, the heat dissipation performance is supplemented through the metal protection member 120 without increasing the overall thickness of the heat dissipation sheet 100 for wireless charging, thereby improving the overall heat dissipation performance.

In addition, since the metal protection member 120 according to the present invention is made of a metal material to increase the rigidity of the material itself, the rigidity is greatly increased compared to a conventional protective film made of a material such as PET. Accordingly, unlike the conventional protective film, which is easily damaged by scratches against external impact, the heat dissipation member 110 is protected from external impact through a metal material with high rigidity, which is easily damaged by external impact. By preventing it, it is possible to more stably protect the heat dissipating member 110 from the external environment.

As an example, when the heat dissipation 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, in particular , When applied to a wireless power receiving module, which is a form of the wireless power charging module 1, the heat generated from the antenna unit 10 is further reduced without increasing the thickness of the wireless power receiving module, which is severely limited in overall thickness. By being able to discharge effectively, it is possible to increase the wireless charging efficiency.

Such a metal protection member 120 is attached to one surface of the heat dissipation member 110 via an adhesive layer 130. At this time, the other surface of the heat dissipation member 110 includes at least one selected from polyethylene terephthalate (PET), polypropylene (PP), and polyterephthalate (PTFE) for the purpose of simply protecting the heat dissipation member 110 A protective film 140 implemented as a fluororesin-based film may be additionally provided. This is, when the heat dissipation sheet 100 for wireless charging according to the present invention is attached to one surface of the shielding sheet 200, the protective film 140 and the protective film 140 without the need to use a separate adhesive means by removing the protective film 140 It is to be attached to the shielding sheet 200 through the adhesive layer 130 disposed between the heat dissipation member 110.

Meanwhile, since the adhesive layer 130 is provided to have thermal conductivity, the heat dissipation effect may be further increased. Such an adhesive layer 130 may be provided with a pressure-sensitive adhesive including a component having thermal conductivity, or may be in the form of a plate-shaped substrate and a pressure-sensitive adhesive including a component having thermal conductivity on at least one surface of the substrate.

For example, the pressure-sensitive adhesive may be selected from acrylic, urethane-based, and silicone-based pressure-sensitive adhesives, and may be made of a thermally conductive adhesive including 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, inorganic material, organic material, or a mixture thereof, and specifically aluminum (Al), nickel (Ni), copper (Cu), tin (Sn), zinc (Zn), tungsten Metal powders such as (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); And as the carbon material, one or more selected from organic powders such as graphite, graphene, carbon nanotubes (CNT), and carbon nanofibers (CNF) may be used. In addition, the thermally conductive filler preferably contains at least one carbon material selected from the group consisting of graphite, graphene, carbon nanotubes (CNT), carbon nanofibers (CNF), and the like among the materials listed above. In addition, the thermally conductive filler may be mixed in an appropriate amount within a range that does not lower the adhesive strength 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 per 100 parts by weight of the adhesive. This is because if the content of the thermally conductive filler is less than 0.5 parts by weight, the thermal conductivity due to its content is insignificant, and if it exceeds 500 parts by weight, the content of the pressure-sensitive adhesive is relatively small, and the adhesive strength may be lowered. In addition, the thermally conductive pressure-sensitive adhesive may further include a dispersant for uniform dispersion of the thermally conductive filler or a crosslinking agent for controlling adhesive properties. In addition, the thermally conductive pressure-sensitive adhesive may optionally further include an antioxidant, a defoaming agent, a thickener, a flame retardant, etc. within a range that does not adversely affect adhesion.

On the other hand, the metal protection member 120 ′ according to the present invention includes a base layer 123 made of a metal material for heat dissipation as shown in FIG. 5, and a coating layer that is radiation coated on at least one surface of the base layer 123 ( 124). Here, as the coating layer 124, a ceramic having a nano-sized particle size or a metal oxide including carbon black may be used.

Such a coating layer 124 further increases the heat dissipation effect of the metal protection member 120 ′ by increasing the emissivity.

In addition, the metal protection member 120 may form an oxide film by oxidizing the surface of a metal material constituting the metal protection member 120 through blackening. For example, when the metal material is copper, the oxide film may be an oxide film such as CuO and Cu ₂ O.

Through this, it is possible to prevent corrosion to minimize cracking, improve adhesion and adhesion according to an increase in surface area, and increase the emissivity of the material itself to further increase heat dissipation characteristics without increasing the overall thickness.

In addition, in the case of the oxide film formed on the surface of the metal layer, it serves as an insulating layer to increase the overall resistance value, thereby reducing the generation of eddy currents during wireless charging, thereby increasing charging efficiency. Here, the blackening treatment may be performed using a chemical, heat treatment, or plasma treatment.

Meanwhile, in the metal protection member 120 according to the present invention, as shown in FIGS. 1 to 4, at least one slit 122 having a predetermined length is formed through it to increase the resistance of the metal protection member 120. It is also possible to increase charging efficiency by suppressing the occurrence of eddy current during wireless charging.

Here, the slit 122 may be provided entirely or partially in the metal protection member 120, and when the slit 122 is provided in plural, a plurality of slits 122 are arranged in a predetermined pattern. It can be or can be arranged in a random form.

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

That is, the slit 122 is perpendicular to the length direction of the pattern constituting the wireless charging antenna 12 when the wireless charging antenna 12 is formed in a rectangular pattern as shown in FIG. 3A. It may be provided to have a certain length in the direction.

In addition, the slit 122 is a direction perpendicular to the tangent line of the pattern constituting the wireless charging antenna 12 when the wireless charging antenna 12 is formed in a circular pattern as shown in FIG. 3B It may be formed to have a certain length.

In addition, although not shown, when the wireless charging antenna 12 is provided in a form having both a straight section and a curved section, a slit formed in the straight section constitutes the wireless charging antenna 12 as shown in FIG. 3A. It is provided to have a certain length in a direction perpendicular to the longitudinal direction of the pattern, and the slit formed in the curved section is constant in a direction perpendicular to the tangent line of the pattern constituting the wireless charging antenna 12 as shown in FIG. 3B. It is formed to have a length.

The slit 122 may be provided 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 inward from the edge of the metal protection member 120 by a predetermined length (see FIGS. 4C and 4D), or the metal protection member ( It may be provided in the form of a through hole 122b penetrating the interior of 120 (see FIGS. 4A and 4B), and the cutout 122a and the through hole 122b may be provided in a combination form ( Not shown).

Although an embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in the present specification, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same idea. It will be possible to easily propose other embodiments by changing, deleting, adding, etc., but it will be said that this is also within the scope of the present invention.

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

Claims (10)

As a heat dissipation sheet to radiate heat generated during wireless charging,
Heat dissipation member; And
Including; a metal protection member attached to one surface of the heat dissipation member via an adhesive having thermal conductivity to protect the heat dissipation member and function as an auxiliary heat dissipation member,
The metal protection member is a heat radiation sheet for wireless charging including at least one slit formed to have a predetermined length in a region corresponding to the wireless charging antenna disposed on one side of the heat radiation member. The method of claim 1,
The heat dissipation member is made of graphite material,
The metal protection member is a heat dissipation sheet for wireless charging made of a copper foil including a copper foil or a copper film. delete The method of claim 1,
The metal protection member is a heat radiation sheet for wireless charging comprising a base layer made of a metal material and a coating layer coated on at least one surface of the base layer. The method of claim 4,
The coating layer is a heat radiation sheet for wireless charging comprising at least one selected from ceramics and metal oxides. delete delete delete delete delete

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