KR102751793B1 - Heat dissipation sheet and electronic device comprising the same - Google Patents

Abstract

A heat-radiating sheet is provided. According to one embodiment of the present invention, a heat-radiating sheet is implemented by including a carbon sheet having an x-y plane and a shape-deforming portion that stretches or bends when an external force is applied. According to this, it has excellent bending and stretching characteristics that can cover an uneven heating surface having steps or curves with excellent adhesion without damage such as cracks, or can connect structures that are located on different planes or are spaced apart from each other with height differences. In addition, since it has excellent heat transfer characteristics, heat can be quickly transferred from one side where a heat source is located to the other side that is connected and shares an uneven surface, or heat can be very quickly transferred from a structure where a heat source is located to another spaced structure and released to the outside, so that performance degradation of an electronic device due to heat generation can be minimized.

Description

Heat dissipation sheet and electronic device comprising the same {Heat dissipation sheet and electronic device comprising the same}

The present invention relates to a heat-dissipating sheet, and more specifically, to a heat-dissipating sheet having elasticity and an electronic device including the same.

Recently, electronic devices are adopting a variety of small and high-performance components in accordance with the trend toward high performance, multi-functionality, and light and compact miniaturization. The amount of heat generated by various electronic components that are miniaturized and high-performance is increasing. Accordingly, it is becoming a very important task to effectively dissipate the large amount of heat generated in the narrow space of electronic devices to prevent malfunction and damage to electronic components.

Accordingly, recent electronic devices are increasing the number of structures for heat dissipation, such as heat sinks and heat plates, inside them. However, due to the trend toward thinner and smaller devices, the sizes of various heat dissipation structures for heat dissipation are also getting smaller. As a result, it is no longer sufficient to dissipate the heat generated from a single heat source through a single heat dissipation structure placed adjacent to it.

In addition, since the internal structure of a thin and miniaturized electronic device is very complex and narrow, when a single electronic device has multiple heat dissipation structures or a structure having a heat source and a heat dissipation structure are separated, multiple heat dissipation structures or a structure having a heat source and a heat dissipation structure adjacent to it are located on different planes, or even when located apart from each other on the same plane, there may be a height difference, making it difficult to quickly dissipate a large amount of heat generated in the electronic device in a short period of time by transferring heat from one structure to another structure separated from it.

In particular, in order to transfer heat between structures that are spaced apart from each other, a heat transfer member that mediates these structures is required, and when these structures are located on different planes or have height differences, the heat transfer member must have bending or folding characteristics. However, a heat transfer member that has both excellent heat transfer characteristics and bending/folding characteristics has not yet been developed.

In other words, general heat dissipation sheets have been manufactured from various sheet-shaped metals or carbon-based materials such as sheet-shaped graphite, which are usually known to have excellent thermal conductivity. However, if these heat dissipation sheets have bending or folding characteristics, their heat dissipation performance is insufficient. On the other hand, if the heat dissipation performance is excellent, their bending or folding characteristics are insufficient or almost non-existent. Therefore, cracks or other damage may occur during bending or folding, which may deteriorate their heat dissipation characteristics. In addition, heat dissipation sheets in the form of heat dissipation fillers dispersed inside a flexible polymer matrix have bending or folding characteristics but lack heat transfer characteristics. Therefore, they are not suitable as heat dissipation members for interconnecting spaced structures or covering uneven heat-generating surfaces such as steps or curves.

Publication of Patent Publication No. 2016-0116366

The present invention has been made in consideration of the above points, and aims to provide a heat-dissipating sheet having excellent heat transfer properties and excellent bending and elastic properties capable of covering an uneven heating surface with steps or curves without damage such as cracks, or connecting structures that are located on different planes or are spaced apart from each other with steps in height, and an electronic device including the same.

In order to solve the above-described problem, the present invention provides a heat dissipation sheet having a carbon sheet having an x-y plane and a shape-deforming portion that stretches or bends in response to an applied external force.

According to one embodiment of the present invention, the carbon sheet further includes a heat transfer portion including a first portion and a second portion spaced apart in the x-axis direction, and the shape deformation portion can be positioned between the first portion and the second portion.

Additionally, the carbon sheet may include at least one of a natural graphite sheet, an artificial graphite sheet, and a graphene sheet.

Additionally, the carbon sheet may have a thickness of 10 to 100 μm.

In addition, the above-mentioned shape-deforming portion may include a plurality of portions spaced apart from each other in the y-axis direction at a predetermined interval and a wave-shaped penetration pattern in which mountains and valleys are alternately repeated in the x-axis direction. In this case, the shortest distance between the penetration patterns of two adjacent waves may be 600 μm or less.

Additionally, the penetration pattern may have a pitch of 3.8 mm or less in one waveform.

In addition, the shape-deforming portion may include a bending pattern in which mountains and valleys are formed in the z-axis direction perpendicular to the x-y plane, the mountains and valleys are alternately repeated in the x-axis direction, and the mountains and valleys are each continuous in the y-axis direction.

Additionally, the above-mentioned bending pattern may have a pitch of 0.20 to 4.0 mm, and the distance between adjacent mountains and valleys may be 2.0 mm or less.

In addition, the invention may further include a first protective member covering at least one side of the x-y plane of the carbon sheet and a second protective member covering both sides of the x-y plane of the carbon sheet on an upper side of the first protective member.

In addition, the first protective member may be a protective film having an adhesive layer on one surface, and the second protective member may be a binder sheet having a resin surface exposed on both surfaces, wherein the resin surface is implemented with at least one of a silicone-based resin, a thermoplastic polyurethane (TPU) resin, and a rubber-based resin.

In addition, the second protective member may be configured with a damage prevention member arranged at a position corresponding to a shape-deformed portion of the carbon sheet to prevent damage to the shape-deformed portion during elongation, and an attachment member arranged at a position corresponding to the remaining portion of the carbon sheet to attach the heat-radiating sheet to the skin surface.

Additionally, the first protective member may have a thickness of 6 to 10 μm, and the second protective member may have a thickness of 4 to 10 μm.

In addition, the present invention provides a method for manufacturing a heat-radiating sheet, including the steps of (1) laminating a first protective member so as to cover at least one side of a region in which a shape-deforming portion is to be formed among carbon-based sheets, (2) forming a shape-deforming portion, and (3) forming a second protective member on both sides of the carbon-based sheet.

According to one embodiment of the present invention, the step (2) can be performed by punching so that a wave-shaped penetration pattern in which mountains and valleys alternately repeat in the x-axis direction is formed at a predetermined interval in the y-axis direction.

Alternatively, the step (2) may be performed by applying pressure so that mountains and valleys are formed in the z-axis direction perpendicular to the x-y plane, the mountains and valleys are alternately repeated in the x-axis direction, and the mountains and valleys each have a continuous bending pattern in the y-axis direction.

In addition, the present invention provides a heat transfer assembly for transferring heat from one of first and second structures, which are spaced apart from each other, to the other structure, comprising: a first structure having a first surface; a second structure having a second surface different from the first surface in at least one of a surface direction and a height; and a heat dissipation sheet according to the present invention, wherein one surface on one side in the x-axis direction is in contact with the first surface of the first structure, one surface opposite to the one side is in contact with the second surface of the second structure, and a part or all of a shape-deforming portion is positioned between the first structure and the second structure.

According to one embodiment of the present invention, the first structure and the second structure may each be one of a heat sink, a heat sink, a circuit board, a bracket, a display panel, a battery, and a housing.

In addition, the present invention provides an electronic device having a heat transfer assembly according to the present invention.

Hereinafter, terms used in the present invention are defined.

The term 'banding' used in the present invention includes bending with a predetermined radius of curvature, or completely bending so that one side is folded so that it meets another, or folding into two parts with one side forming a specific angle, or completely wrapping with a predetermined radius of curvature (e.g., rolling).

According to the present invention, the heat-dissipating sheet has excellent adhesive properties that enable it to cover an uneven heating surface with steps or curves without damage such as cracks, or to connect structures that are located on different planes or are spaced apart from each other with height differences. In addition, since it has excellent heat transfer properties, it can quickly transfer heat from one side where a heat source is located to the other side that shares an uneven surface, or can very quickly transfer heat from one structure where a heat source is located to another spaced structure and release it to the outside, so as to minimize performance degradation of electronic devices due to heat generation.

Figure 1 is a plan view of a heat dissipation sheet according to one embodiment of the present invention.
Figure 2 is a cross-sectional view along the XX' boundary line of Figure 1.
Figure 3 is a cross-sectional view of a heat dissipation sheet according to another embodiment of the present invention.
Figure 4 is a plan view of a heat dissipation sheet according to one embodiment of the present invention.
Figure 5 is a cross-sectional view along the YY' boundary line of Figure 4.
Figure 6 is an optical microscope photograph of a shape-deformed portion included in a heat-radiating sheet according to one embodiment of the present invention.
Figures 7a to 7c are photographs of shape-deformed parts manufactured with different pitch sizes in a heat dissipation sheet according to one embodiment of the present invention.
Fig. 8 is a photograph of a roller having a pattern formed thereon for manufacturing a curved pattern formed on a heat-radiating sheet according to Fig. 7b.
Figures 9a to 9c are diagrams showing various usage states of a heat dissipation sheet according to one embodiment of the present invention.
Figure 10 is a photograph of a self-made simulation system for measuring thermal characteristics of a specimen.
Figures 11 and 12 are graphs showing the results of thermal characteristic measurements for the heat dissipation sheet of Example 1 according to the present invention and the results of thermal imaging photography at each point, respectively.
Figure 13 is a photograph of another self-made simulation system for measuring thermal characteristics of the specimen, and
Figure 14 is a graph showing the results of thermal characteristic measurements for Examples 1, 3, and Comparative Example 2 according to the present invention.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice 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 that are 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.

Referring to FIGS. 1 and 2, a heat-radiating sheet (200) according to one embodiment of the present invention comprises a carbon sheet (100) having an x-y plane and a shape-deforming portion (120) that is stretched or bent by an applied external force. In addition, the carbon sheet (100) further comprises a heat transfer portion (110) comprising a first portion (111) and a second portion (112) spaced apart in the x-axis direction, and the shape-deforming portion (120) may be positioned between the first portion (111) and the second portion (112). Alternatively, unlike as illustrated in FIGS. 1 and 2, the shape-deforming portion may be provided only in a predetermined region from an end portion on one side of the carbon sheet (100) in the x-axis direction, or the shape-deforming portion may be provided in the entire region.

The above heat-radiating sheet (200) is a carbon sheet that is continuous in all directions within the x-y plane, and can exhibit very high horizontal heat transfer characteristics compared to metal sheets used as conventional heat-radiating members, thereby having an advantage in that heat from one side can be quickly transferred to the other side from a heat source located on one side or between structures that are spaced apart from each other to a heat-radiating member such as a heat sink located on the opposite side. The carbon sheet (100) may include, for example, at least one of a natural graphite sheet, an artificial graphite sheet, and a graphene sheet. In addition, the carbon sheet (100) may be provided with one type of any one of these, or may be in the form of two or more sheets of one or two or more types of these being laminated.

In addition, the carbon sheet (100) may be set to a thickness in the range of 10 to 100 ㎛. If the thickness is less than 10 ㎛, the mechanical strength is weak and it is easily damaged by an external force applied, and it may be difficult to form a shape-deformed portion. In addition, if the thickness exceeds 100 ㎛, it may run counter to the trend toward lightness and miniaturization, and thus it is not suitable. In addition, depending on the specific material of the carbon sheet, such as artificial graphite, it may not be easy to manufacture a single plate-shaped sheet with such a thickness.

The above-mentioned shape deformation part (120) has a function of causing the carbon sheet (100) to stretch or bend due to an external force applied to the carbon sheet. For example, when the shape deformation part (120) is located between the first part (111) and the second part (112) of the heat transfer part (110), the first part (111) and the second part (112) can be stretched and/or bent due to an external force applied so that they have different heights or surface directions.

Although carbon sheets have excellent heat transfer properties in a horizontal direction compared to metal sheets, they lack the strength, flexibility, and tensile properties to withstand stretching and bending. As a result, it may be difficult to withstand external forces generated when structures are spaced apart in various positions or when both ends of the carbon sheets are attached to an uneven same plane. By providing a shape-deforming portion (120), the carbon sheets can be structurally made to have stretching and/or bending properties without material deformation or modification of the carbon sheets.

Meanwhile, in order to allow a specific region of a continuous carbon sheet (100) in the omnidirectional xy plane to have different shape deformation characteristics from other regions, a plurality of shape deformation portions (120) may be arranged at a predetermined interval in the y-axis direction and may include a wave-shaped penetration pattern (121) in which mountains and valleys are alternately repeated in the x-axis direction, thereby minimizing a decrease in heat transfer efficiency in the x-axis direction while having elasticity and/or bending characteristics. In addition, among the distances (d ₁ , d ₂ ) between adjacent penetration patterns (121), the shortest distance may be 600 ㎛ or less, more preferably 100 to 600 ㎛, thereby further improving the desired elasticity and bending characteristics while minimizing a decrease in heat transfer efficiency and damage to the carbon sheet due to the provision of the penetration pattern.

In addition, the penetration pattern (121) may have a pitch in one penetration pattern (121), for example, a gap between one mountain and an adjacent mountain, or a gap between one valley and an adjacent valley, of 3.8 mm or less, more preferably 3.0 mm or less, even more preferably 2.2 mm or less, and more preferably 1.2 to 2.2 mm. If the pitch in one penetration pattern exceeds 3.8 mm, the amount of deformable length in the shape-deformable portion is small, so there is a high risk of damage to the carbon-based sheet during elongation. In addition, if the pitch is 1.2 mm or less, there is a risk of damage to the carbon-based sheet or a decrease in heat transfer efficiency when forming the penetration pattern.

In addition, it should be noted that the above-described plurality of penetration patterns (121) may be configured such that the spacing or spacing pattern between adjacent penetration patterns is the same, but may also be formed to have a gradient in which the spacing becomes narrower or wider as it goes from the center to both sides along the y-axis.

In addition, referring to FIGS. 4 and 5, the carbon sheet (300) in the heat-radiating sheet (400) may include a shape-deformed portion (320) including a bending pattern in which mountains and valleys are formed in the z-axis direction perpendicular to the x-y plane, the mountains and valleys are alternately repeated in the x-axis direction, and the mountains and valleys are each continuous in the y-axis direction. At this time, the bending pattern may have a pitch of 0.2 to 4.0 mm, and the distance between adjacent mountains and valleys may be 2.0 mm or less, thereby obtaining sufficient elasticity and/or bending characteristics without a decrease in heat transfer efficiency, unlike the shape-deformed portion illustrated in FIG. 1. However, when considering the structure of the shape-deformed portion (120, 320), the heat-dissipating sheet (400) illustrated in FIG. 4 has mountains and valleys formed in the z-axis direction, so the thickness of the carbon sheet (300) increases in the shape-deformed portion (320), and in terms of implementing a thin heat-dissipating sheet, the heat-dissipating sheet (200) illustrated in FIG. 1 may be more advantageous.

In addition, a heat transfer section (110, 310) including a first portion (111, 311) and a second portion (112, 312), which are different regions spaced apart in the x-axis direction within the carbon sheet (100, 300), may be arranged on both sides of the shape deformation section (120, 320). In this case, the first portion (111, 311) and the second portion (112, 312) become sections that contact specific surfaces of the spaced structures, respectively, and heat transferred through the specific surface of one of the structures can be transferred to another structure through the shape deformation section (120, 320).

In addition, the shape deformation part (120, 320) may have a length of 20 ㎛ or more, which is the distance between the boundary line of the first part (111, 311) and the boundary line of the second part (112, 312). If the length of the shape deformation part (120, 320) is less than 20 ㎛, the applied external force may be received by the first part (111, 311) or the second part (112, 312) rather than the shape deformation part (120, 320), so there is a risk of damage such as cracks occurring in the first part (111, 311) or the second part (112, 312).

Meanwhile, the heat-radiating sheet (200, 400) may further include a first protective member (140, 340) that covers at least the shape-deformed portion on one of the two sides, which are the x-y planes, of the carbon-based sheet (100, 300) described above. Alternatively, as illustrated in FIG. 3, the first protective member (140) may be arranged on both sides of the carbon-based sheet (100). The first protective member (140, 340) prevents damage such as cracks or breakage that occur in the area where the shape-deformed portion (120, 320) is to be formed during the process of implementing the shape-deformed portion (120, 320), as described in the manufacturing method described below, and prevents the carbon-based sheet (100, 300) from being torn or damaged due to external force, such as stretching, when using the heat-radiating sheet. The above first protective member (140, 340) may be a protective film (141, 341) having an adhesive layer (142, 342) provided on one surface. The adhesive layer (142, 342) may be formed of a known adhesive, and thus the present invention is not particularly limited thereto. The adhesive layer (142, 342) may be formed of an adhesive layer-forming composition including an adhesive component, preferably at least one selected from the group consisting of acrylic resin, urethane resin, epoxy resin, silicone rubber, acrylic rubber, carboxylic nitrile elastomer, phenoxy, and polyimide resin, more preferably an acrylic resin, and even more preferably an acrylic resin having heat resistance. In addition, the adhesive layer-forming composition may further include a curing agent when the adhesive component is a curable resin, and may further include an additive such as a curing accelerator depending on the purpose. The above curing agent may be any curing agent commonly used in the art without limitation, and preferably includes at least one selected from the group consisting of an epoxy curing agent, a diisocyanate curing agent, a secondary amine curing agent, a tertiary amine curing agent, a melamine curing agent, an isocyanate curing agent, and a phenol curing agent, and more preferably includes an epoxy curing agent. In addition, the adhesive layer (142, 342) may have a thickness of 2 to 10 μm, and preferably 3 to 6 μm.

In addition, the protective film (141, 341) may be at least one of a polyester film such as polyethylene terephthalate (PET), a polyimide (PI) film, and a polyamide (PA) film such as nylon 6 or nylon 66. In addition, the thickness of the protective film (141, 341) may be 2 to 4 ㎛.

Meanwhile, the first protective member (140, 340) may be provided to cover at least the shape-deforming portion (120, 320), and as another example, may be provided to cover the entire surface of the carbon sheet (100, 300) in the x-y plane.

In addition, the heat-dissipating sheet (200, 400) may further include a second protective member (150, 150', 350) that covers both sides of the carbon sheet (100, 300) in the x-y plane above the first protective member (140, 340). As shown in FIGS. 2 and 5, the second protective member (150, 150', 350) prevents cracks, breakage, etc. that occur in the carbon sheet (100, 300) on which the first protective member (140, 340) is not formed, and prevents materials constituting the carbon sheet from flying due to cracks or breakage that occur. Or, as illustrated in FIG. 3, even when the first protective member (140) is formed on both sides, it serves to prevent additional damage and cracks occurring in the shape-deformed portion. In addition, it provides a function as an adhesive member for attaching the heat-radiating sheet (200, 400) to the skin surface. To this end, the second protective member (150, 350) may be a binder sheet formed of a material having a certain level of protective function against external force and excellent elasticity, and the binder sheet may be a sheet manufactured from a thermoplastic elastomer resin such as thermoplastic polyurethane (TPU), thermoplastic polyamide elastomer (TPA), thermoplastic plastic copolyester (TPC), or a silicon-containing sheet. In this case, the second protective member (150, 350), which is the binder sheet, may have a thickness of 4 to 10 ㎛, which may be advantageous in achieving the effect through the second protective member (150, 350).

Or, as illustrated in FIG. 3, the second protective member (150') may be configured with a damage prevention member (150'a) arranged at a position corresponding to the shape deformation member (120, 320) of the carbon sheet (100, 300) to prevent damage to the shape deformation member (120, 320) during elongation, and an attachment member (150'b) arranged at a position corresponding to the remaining portion of the carbon sheet (100, 300) excluding the shape deformation member (120, 320) to attach the heat dissipation sheet (200, 400) to the adhesion surface. At this time, the above-described binder sheet may be arranged on the damage prevention member (150'a), and a typical adhesive or bonding binder sheet may be arranged on the attachment member (150'b), and the present invention is not particularly limited thereto.

The heat dissipation sheet (200, 400) according to one embodiment of the present invention described above can be manufactured through the method described below. However, it is not limited thereto.

Specifically, a heat-radiating sheet (200, 400) can be manufactured by including (1) a step of laminating a first protective member (140, 340) to partially or completely cover at least one side or both sides of an area where a shape-deforming portion (120, 320) is to be formed among carbon-based sheets (100, 300), (2) a step of forming a shape-deforming portion (120, 320), and (3) a step of forming a second protective member (150, 150', 350) on both sides of the carbon-based sheets (100, 300).

Step (2) is described as a manufacturing method excluding any overlapping parts with the description of the heat-dissipating sheet (200, 400) described above.

The shape-deforming portion (120, 320) can be implemented in various structurally deformed forms as illustrated in FIGS. 1 to 5 described above, and can be manufactured by selecting an appropriate method according to the desired structural form. For example, the shape-deforming portion (120) illustrated in FIGS. 1 and 2 can be performed through a conventional punching process so that a penetration pattern (121) that is a waveform of the desired shape is formed, and at this time, the punching process can be performed once or multiple times repeatedly to adjust the interval between the penetration patterns to the desired level.

In addition, the shape deformation part (320) illustrated in FIGS. 4 and 5 may be formed by pressing a carbon sheet (100, 300) using a press or a roller as illustrated in FIG. 8, in which mountains and valleys are formed in the z-axis direction perpendicular to the x-y plane, the mountains and valleys are alternately repeated in the x-axis direction, and a pattern corresponding to the bending pattern is reversely transferred so that the mountains and valleys each have a continuous bending pattern in the y-axis direction.

In addition, step (3) is a step of forming a second protective member (150, 350) on both sides of a carbon sheet (100, 300) having a shape-deforming portion (120, 320). The second protective member (150, 350) can be formed by forming a separately manufactured binder sheet through a conventional lamination process, or by forming a binder sheet-forming composition on both sides of the carbon sheet (100, 300) and then drying or drying and curing.

In addition, as illustrated in FIG. 3, when the second protective member (150') is configured such that members of two different materials cover different areas, for example, a damage prevention member (150'a) may be first formed in an area corresponding to a shape-deformed portion (120, 320) of a carbon sheet (100, 300), and then an attachment member (150'b) may be formed in the remaining area.

A heat dissipation sheet (200, 400) implemented by a manufacturing method according to an embodiment of the present invention described above is useful as a heat dissipation sheet in which one side and the other side of the heat dissipation sheet (200, 400), for example, a first part (111, 311) and a second part (112, 312), are attached to each of a first surface of a first structure and a second surface of a second structure, respectively, so as to correspond to each other, in a plane of a structure having curves or steps depending on a continuous plane or position, or structures spaced apart from each other, particularly, different in at least one of a surface direction and a height, so as to transfer heat from the first surface side to the second surface side.

Accordingly, the present invention can implement a heat transfer assembly that transfers heat from one of the first and second structures, which are spaced apart from each other, to the other structure using the heat dissipation sheet (200, 400) described above.

Specifically, the heat transfer assembly is implemented by including a first structure having a first surface, a second structure having a second surface different from the first surface in at least one of a surface direction and a height, and a heat dissipation sheet arranged such that one surface on one side in the x-axis direction is in contact with the first surface of the first structure, one surface on the opposite side of the one side is in contact with the second surface of the second structure, and a part or all of a shape-deforming portion is located between the first structure and the second structure.

Referring to FIGS. 9A to 9C, the heat transfer assembly (1000, 1001, 1002) includes a structure (500, 510, 520) including a first structure (501, 511, 521) and a second structure (502, 512, 522) that are spaced apart from each other, and a heat dissipation sheet (200), and one side of the heat dissipation sheet (200) in the x-axis direction is in contact with the first surface of the first structure (501, 511, 521), and one side of the heat dissipation sheet (200) opposite to the one side is in contact with the second surface of the second structure (502, 512, 522), so that one of the first structure (501, 511, 521) and the second structure (502, 512, 522) is connected via the heat dissipation sheet (200). It has a heat dissipation structure that transfers heat to another structure.

In particular, as shown in FIG. 9a, the first structure (501) and the second structure (502) are positioned on the same plane, and the surface directions of the upper surfaces of each of these structures are the same, but there is a height difference between the structures, as shown in FIG. 9c, the surface directions of the upper surface of the first structure (521) and the lower surface of the second structure (522) are the same, but the two structures exist on different planes, or as shown in FIG. 9b, the surface directions of the first structure (511) and the second structure (512) are different and the two structures exist on different planes, and an external force is applied to the heat dissipation sheet (200) attached to the first structure (501, 511, 521) and the second structure (502, 512, 522), but due to the elasticity and/or bending characteristics of the heat dissipation sheet (200), the shape deformation portion (120) of the heat dissipation sheet (200) Heat from one side of the first structure (501, 511, 521) and the second structure (502, 512, 522) can be easily transferred to the other side without damage or destruction of the first and second parts on both sides.

The above first structure (501, 511, 521) and second structure (502, 512, 522) can each independently be any one of a heat sink, a heat sink, a circuit board, a bracket, a display panel, a battery, and a housing, and it is to be noted that any known component constituting an electronic device that is not listed above can also be a structure.

The present invention will be described more specifically through the following examples, but the following examples do not limit the scope of the present invention, and should be interpreted as helping to understand the present invention.

<Example 1>

A carbon sheet having a thickness of 25 ㎛, a length of 11 cm in the x-direction, and a width of 5.4 cm in the y-direction was prepared as an artificial graphite. Thereafter, a first protective member having an acrylic adhesive layer having a thickness of 4 ㎛ and a PET protective film having a thickness of 3 ㎛ on one side thereof was laminated to one side of the carbon sheet. Thereafter, as shown in FIG. 6, a wave-shaped penetration pattern was formed through punching, and then a second protective member having a thickness of 6 ㎛, which has a damage protection part arranged to correspond to a shape-deformed part corresponding to the punched part of the carbon sheet and an attachment part arranged to correspond to the remaining part of the carbon sheet, was laminated to both sides of the carbon sheet to manufacture a heat-dissipating sheet. At this time, the damage protection part of the second protective member was made of a TPU binder, and the attachment part was made of an acrylic binder. In addition, the length of the shape-deformed part based on the x-axis direction was 1 cm.

<Experimental Example 1>

The heat dissipation sheet according to Example 1 was placed on a simulation system having an LED installed on one side as shown in Fig. 10, and then 16 V and 97 mA of current were applied to the LED, and the temperature was measured at points #1 to #6 at 5-minute intervals for 20 minutes, and the results are shown in Figs. 11 and 12. At this time, a 1 kg weight was placed on the upper part of the heat dissipation sheet before applying the current so that it was in close contact with the simulation system, and insulating foam was attached to the side where the LED was placed so that a flow of heat was generated in which the heat was transferred from point #1 to point #6.

At this time, the outside relative humidity of the space where the experiment was conducted was 46 to 47%, and the temperature was 24.1 to 24.3℃.

As can be seen in Figures 11 and 12,

At point #1, the temperature increase rate decreases as time passes, indicating that a heat dissipation effect has occurred. At points #1 to #6, the temperature increases as time passes, indicating that heat is being transferred from point #1 to point #6.

<Example 2>

A heat-radiating sheet was manufactured in the same manner as in Example 1, except that the thickness of the carbon sheet was changed to 19 μm, and the first protective member was changed to have an acrylic adhesive layer having a thickness of 4 μm and a PET protective film having a thickness of 2 μm on one side, but arranged on both sides of the carbon sheet.

<Comparative Example 1>

A heat-radiating sheet was manufactured in the same manner as in Example 2, but without punching out the carbon sheet.

<Experimental Example 2>

The heat dissipation sheets according to Example 2 and Comparative Example 1 were placed on a simulation system having four LEDs installed on one side, as illustrated in FIG. 13, so that the shape-deformed portion was located between points #2 and #3. A 1 kg weight was then placed on the upper part of the heat dissipation sheet so that it was in close contact with the simulation system, and insulating foam was attached to the side where the LEDs were placed so that a flow of heat was generated from point #1 to point #5. Thereafter, a current of 750 mA was applied to each LED, and the temperature was measured at points #1 to #5 after 30 minutes, and the results are shown in Table 1 below. At this time, the external relative humidity of the space where the experiment was conducted was 46%, and the temperature was 24.2℃.

In addition, in order to examine durability in terms of heat dissipation characteristics, changes in heat dissipation characteristics after repeated stretching were examined. Specifically, for the heat dissipation sheet according to Example 2, the left side of the length of the heat dissipation sheet was folded to the right based on the shape-deformed portion so that the shape-deformed portion was elongated by 5% or 10%, and then relaxation was repeated a total of 100 times. Then, current was applied to the LED using the same method, and the temperature was measured at points #1 to #5 after 30 minutes, and the results are shown in Table 1 below.

Comparative Example 1 Example 2 Example 2 Example 2 Presence or absence of shape deformation doesn't exist Penetration pattern Penetration pattern Penetration pattern 100 times repeat folding doesn't exist doesn't exist 5% extension 10% extension Temperature by branch
(℃) #1 71.1 72.6 72.7 72.6 #2 58.0 58.2 58.3 58.3 #3 48.2 46.7 47.2 47.3 #4 43.9 42 42.1 42.6 #5 40.6 39 39.1 39.1 Temperature difference between point #1 and point #5 (℃) 30.5 33.6 33.6 33.5

As can be seen in Table 1,

It can be seen that the heat dissipation sheet of Example 2, although equipped with a penetration pattern, does not show a significant decrease in the thermal conductivity characteristics in the longitudinal direction compared to Comparative Example 1 which does not have a penetration pattern.

In addition, it can be confirmed that the heat dissipation characteristics of the heat dissipation sheet according to Example 2 are exhibited at a level similar to that before the durability evaluation even after being folded 100 times at the level of 5% or 10%, even though it has a shape-deforming portion that is a penetration pattern. Through this, it can be seen that the heat dissipation characteristics are fully exhibited even after repeated stretching.

<Example 3>

A carbon sheet having a thickness of 25 ㎛, a length of 11 cm in the x-direction, and a width of 5.4 cm in the y-direction was prepared as an artificial graphite. Thereafter, a first protective member having an acrylic adhesive layer having a thickness of 4 ㎛ and a PET protective film having a thickness of 3 ㎛ on one side of the carbon sheet was laminated. Thereafter, as shown in FIG. 8, an inverse image of a curved pattern to be engraved on a shape-deformed portion was formed, and the carbon sheet was passed through two rollers having a pattern pitch of 0.5 mm and pressed to form a collogated curved pattern on the shape-deformed portion. Thereafter, a second protective member having a thickness of 6 ㎛, which has a damage protection member arranged to correspond to the shape-deformed portion corresponding to the portion of the carbon sheet where the curved pattern is formed, and an attachment member arranged to correspond to the remaining portion of the carbon sheet, was laminated on both sides of the carbon sheet to manufacture a heat-radiating sheet as shown in FIG. 7b. At this time, the damage protection part of the second protective member was made of a TPU material binder, and the attachment part was made of an acrylic binder. In addition, the length of the shape deformation part based on the x-axis direction was 1.5 cm, the total thickness of the manufactured heat-dissipating sheet was 0.6 mm, and the elongation was 110%.

<Example 4>

A heat-radiating sheet as shown in Fig. 7a was manufactured by performing the same process as in Example 3, but changing the pitch of the reverse pattern of the curved pattern formed on the roller to 4 mm. The heat-radiating sheet manufactured at this time had a thickness of 2 mm and an elongation of 110%.

<Example 5>

A heat-radiating sheet as shown in Fig. 7c was manufactured by performing the same process as in Example 3, but changing the thickness of the carbon sheet to 17 μm and changing the pattern pitch, which is the reverse of the curved pattern formed on the roller, to 0.35 mm. The heat-radiating sheet manufactured at this time had a thickness of 0.40 mm and an elongation of 110%.

<Comparative Example 2>

A PET film of the same thickness as in Example 3 was prepared.

<Experimental Example 3>

The heat dissipation sheets according to Examples 1, 3, and Comparative Example 2 were placed on a simulation system having an LED installed on one side, as shown in Fig. 10, so that the shape-deformed portion was positioned between positions #2 and #3, and a 1 kg weight was placed on the upper part of the heat dissipation sheet so that it was in close contact with the simulation system, and insulating foam was attached to the side where the LED was placed so that a flow of heat was generated from point #1 to point #6. Thereafter, 16.0 V and 97 mA of current were applied to the LED, and the temperatures were measured at points #1 to #6 after 15 minutes, and the results are shown in Fig. 14. At this time, the external relative humidity of the space where the experiment was conducted was 46%, and the temperature was 24.2℃.

As can be seen in Figure 14,

In the case of the heat-radiating sheets according to Examples 1 and 3, compared to Comparative Example 2, the temperature at point #1, which is the heat source, is significantly lowered after 15 minutes, and it can be seen that even though a shape-deformation portion is provided, there is an excellent heat transfer effect from point #1 to point #6. However, it can be seen that Example 3, in which a bending pattern is formed as a shape-deformation portion, is somewhat superior in heat dissipation performance than Example 1, in which a penetration pattern is formed.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in this specification, and those skilled in the art who understand the spirit of the present invention will be able to easily suggest other embodiments by adding, changing, deleting, or adding components within the scope of the same spirit, but this will also be considered to fall within the spirit of the present invention.

1000,1001,1002: Heat transfer assembly 200,400: Heat dissipation sheet
110,310: Heat transfer part 120,320: Shape deformation part
140,340: 1st protection member 150,150'350: 2nd protection member

Claims (18)

A carbon sheet having a main surface in the xy plane and including a shape-deforming portion that stretches or bends in response to an applied external force;
A first protective member covering at least one side of the xy plane of the above carbon sheet; and
A heat-radiating sheet comprising: a second protective member covering both main surfaces of the xy plane of the carbon sheet on the upper side of the first protective member, the second protective member having a damage prevention member positioned corresponding to the shape-deforming portion to prevent damage to the shape-deforming portion during elongation, and an attachment member positioned corresponding to the remaining portion of the carbon sheet to attach the heat-radiating sheet to the adhesion surface. In the first paragraph,
The above carbon sheet further includes a heat transfer portion including a first portion and a second portion spaced apart in the x-axis direction, and the shape-deforming portion is a heat dissipation sheet positioned between the first portion and the second portion. In the first paragraph,
The above carbon sheet is a heat-dissipating sheet including at least one of a natural graphite sheet, an artificial graphite sheet, and a graphene sheet. In the first paragraph,
The above carbon sheet is a heat-dissipating sheet with a thickness of 10 to 100 μm. In the first paragraph,
A heat dissipation sheet in which a plurality of the above-mentioned shape-deforming sections are arranged at a predetermined interval in the y-axis direction and include a wave-shaped penetration pattern in which mountains and valleys are alternately repeated in the x-axis direction. In paragraph 5,
A heat-dissipating sheet in which the distance between the penetration patterns of two adjacent waveforms is 600㎛ or less. In paragraph 5,
A heat-dissipating sheet with a pitch of 3.8mm or less in one waveform. In the first paragraph,
A heat dissipation sheet in which the above-mentioned shape-deforming portion has mountains and valleys formed in the z-axis direction perpendicular to the xy plane, the mountains and valleys are alternately repeated in the x-axis direction, and the mountains and valleys are each continuous in the y-axis direction. In Article 8,
The above-mentioned heat-dissipating sheet has a pitch of 0.2 to 4.0 mm and a distance between adjacent mountains and valleys of 2.0 mm or less. delete In the first paragraph,
The above first protective member is a protective film having an adhesive layer on one surface, and the above second protective member is a heat-dissipating sheet which is a binder sheet with a resin surface formed of at least one of a silicone-based resin, a thermoplastic polyurethane (TPU) resin, and a rubber-based resin exposed on both surfaces. delete In the first paragraph,
The above first protective member is a heat-dissipating sheet having a thickness of 6 to 10 μm, and the second protective member is a heat-dissipating sheet having a thickness of 4 to 10 μm. (1) A step of laminating a first protective member so as to cover at least one surface of a region in which a shape-deforming portion is to be formed among carbon sheets having a main surface in the xy plane;
(2) a step of forming a shape deformation portion; and
(3) A method for manufacturing a heat-radiating sheet, comprising: forming a second protective member on both surfaces of a carbon sheet, the second protective member having a damage prevention member positioned corresponding to the shape-deformed portion to prevent damage to the shape-deformed portion during elongation, and an attachment member positioned corresponding to the remaining portion of the carbon sheet to attach the heat-radiating sheet to the skin surface. In Article 14, step (2)
By punching so that a wave-shaped penetration pattern with alternating mountains and valleys in the x-axis direction is formed at a predetermined interval in the y-axis direction,
A method for manufacturing a heat-dissipating sheet, wherein mountains and valleys are formed in the z-axis direction perpendicular to the xy plane, the mountains and valleys are alternately repeated in the x-axis direction, and the mountains and valleys each have a continuous bending pattern in the y-axis direction by applying pressure. A heat transfer assembly that transfers heat from one of the first and second structures, which are separated from each other, to the other structure,
A first structure having a first surface;
A second structure having a second surface having at least one different surface direction and height from the first surface; and
A heat transfer assembly comprising a heat dissipation sheet according to any one of claims 1 to 9, 11 and 13, wherein one side of one side in the x-axis direction is in contact with the first side of the first structure, one side opposite the one side is in contact with the second side of the second structure, and a part or all of the shape-deforming portion is positioned between the first structure and the second structure. In Article 16,
The first structure and the second structure are each a heat transfer assembly, which is one of a heat sink, a heat sink, a circuit board, a bracket, a display panel, a battery, and a housing. An electronic device having a heat transfer assembly according to Article 16.

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