JP2018116079A - Heat dissipation sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat dissipation sheet capable of properly dissipating heat of a transparent display.SOLUTION: Provided is a heat dissipation sheet that is employed in a transparent display and has a thermally conductive layer which is formed like a pattern and contains a thermally conductive material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat-dissipating sheet that can favorably dissipate heat from a transparent display.

  In a display, a heat radiating sheet may be disposed in order to release heat generated from a light source, a power source, an electronic component, and the like to the outside of the display. As a heat radiating sheet, for example, a sheet containing a metal material or a carbon material is used (Patent Documents 1 to 4). In a display, heat tends to accumulate more easily in the center of the screen than in the outer periphery of the screen. Therefore, in the conventional display, in order to increase the thermal conductivity in the surface direction, it is desired that the area of the heat radiating sheet be arranged as wide as possible.

By the way, in recent years, the development of transparent displays has been promoted. The transparent display has a feature that it is possible to observe the scenery and object on the opposite side from the viewer side through the display.
Even in a transparent display, it is necessary to release the heat generated inside the display to the outside. However, as described above, the heat dissipation sheet conventionally used for the display includes a light-shielding material such as a metal material or a carbon material. Moreover, since the area arrange | positioned at a display is large, when it uses for a transparent display, there exists a problem of inhibiting the transparency of a transparent display. Therefore, a heat dissipation sheet suitable for a transparent display is demanded.

JP 2004-347741 A JP 2002-50725 A JP 2009-107904 A JP 2009-250697 A

  This invention is made | formed in view of the said situation, and it aims at providing the heat dissipation sheet which can perform the heat dissipation of a transparent display favorably.

  In order to achieve the above object, the present invention provides a heat radiating sheet for use in a transparent display, which is formed in a pattern and has a heat conductive layer containing a heat conductive material. To do.

  According to the present invention, it is possible to perform heat dissipation of a transparent display satisfactorily by having a patterned heat conductive layer.

  In this invention, you may have the space | gap part provided in the opening part of the said heat conductive layer. This is because it is possible to radiate heat from the transparent display by convection of the air in the gap.

  In this invention, you may have further the heat absorption layer with which the opening part of the said heat conductive layer was filled. This is because heat can be prevented from being accumulated inside the transparent display by causing the heat absorption layer to absorb the heat of the transparent display.

  In the present invention, the pattern of the thermally conductive layer may be a pixel pattern having a pixel opening corresponding to the sub-pixel or pixel pattern of the transparent display. When the heat conductive layer is a pixel pattern, a region that does not hinder the transparency of the transparent display and the visibility of information can be selected, and the heat conductive layer can be disposed over a wide range. Therefore, it can be set as the thermal radiation sheet which can thermally radiate efficiently.

  In this invention, it is preferable to further have the contact | adherence layer which adheres the said transparent display and the said heat radiating sheet. This is because by having the adhesion layer, heat conduction from the transparent display to the heat conductive layer can be promoted. Therefore, it is possible to perform heat dissipation of the transparent display better.

  The heat-dissipating sheet of the present invention has an effect that heat dissipation of the transparent display can be favorably performed.

It is a schematic sectional drawing which shows an example of the thermal radiation sheet of this invention, and another example. It is explanatory drawing explaining the usage method of the thermal radiation sheet | seat of this invention. It is explanatory drawing explaining the thermal radiation method by the thermal radiation sheet of a 1st embodiment. It is a schematic plan view explaining an example of the pattern of the heat conductive layer in this invention. It is a schematic plan view explaining an example of the pattern of the heat conductive layer in this invention. It is a schematic plan view explaining the other example of the pattern of the heat conductive layer in this invention. It is a schematic plan view explaining the other example of the pattern of the heat conductive layer in this invention. It is a schematic plan view explaining the other example of the pattern of the heat conductive layer in this invention. It is a schematic sectional drawing which shows the other example of the thermal radiation sheet | seat of this invention. It is a schematic sectional drawing which shows the other example of the thermal radiation sheet | seat of this invention. It is a schematic sectional drawing which shows the other example of the thermal radiation sheet | seat of this invention. It is explanatory drawing explaining the thermal radiation method by the thermal radiation sheet of a 2nd embodiment. It is a schematic sectional drawing which shows the other example of the thermal radiation sheet | seat of this invention.

Hereinafter, the details of the heat dissipation sheet of the present invention will be described.
The heat dissipation sheet of the present invention is a heat dissipation sheet used for a transparent display, and is characterized by having a heat conductive layer formed in a pattern and including a heat conductive material.

  Here, in the present specification, “transparent” and “transparency” mean that the other surface side can be seen through from one surface side.

  The heat-radiation sheet of this invention is demonstrated using figures. 1A and 1B are schematic cross-sectional views showing an example and other examples of the heat dissipation sheet of the present invention. The heat-dissipating sheet 1 shown in FIGS. 1A and 1B is characterized by having a heat conductive layer 2 formed in a pattern and containing a heat conductive material. FIG. 1A shows a heat radiation sheet 1 a having a heat conductive layer 2 and a gap 3 provided in an opening of the heat conductive layer 2. In FIG.1 (b), it has shown about the thermal radiation sheet | seat 1b which has the heat conductive layer 2 and the heat absorption layer 4 with which the opening part of the heat conductive layer 2 was filled.

  FIG. 2 is an explanatory view illustrating a method of using the heat dissipation sheet of the present invention. The heat dissipation sheet 1 of the present invention is used for a transparent display 20. Specifically, it is disposed on the surface of the transparent display 20. The heat dissipation sheet 1 may be disposed on at least one surface of the transparent display 20. The heat dissipation sheet 1 is usually disposed on the surface of the transparent display 20 on the heat source side. FIG. 2 shows an example in which the heat dissipation sheet 1 is disposed on the surface of the transparent display 20 opposite to the viewer A side.

  In the present invention, the “surface of the transparent display” refers to the outer surface of the panel constituting the transparent display.

According to this invention, it can be set as the thermal radiation sheet which can perform the thermal radiation of a transparent display favorably by having a pattern-shaped heat conductive layer.
Specifically, according to the present invention, the opening of the heat conductive layer can be provided so that the other surface side can be seen through from the one surface side of the heat dissipation sheet by having the pattern-like heat conductive layer. it can. That is, transparency can be imparted to the heat-dissipating sheet by having a patterned heat conductive layer. Therefore, the fall of the transparency of a transparent display by arrange | positioning the heat-radiation sheet of this invention to a transparent display can be suppressed.
Moreover, since a heat conductive layer can be arrange | positioned on the surface of a transparent display, the heat | fever of the center part of a transparent display can be conducted to an outer peripheral part. Therefore, heat dissipation can be performed satisfactorily while maintaining the transparency of the transparent display.

  In addition, according to the present invention, by having a patterned heat conductive layer, it is possible to impart transparency to the heat radiating sheet, so that heat can be radiated without hindering the visibility of information display on the transparent display. Is possible.

  In addition, as shown in Patent Document 1, it is conventionally known that the heat conductive layer of the heat radiation sheet is formed in a pattern shape, but transparency is imparted by forming the heat conductive layer in a pattern shape. The idea is not known. In general, since the heat dissipation sheet is desired to have high thermal conductivity in the surface direction, it is desired that the area of the heat conductive material is wide.

  On the other hand, in the present invention, the heat conductive layer is formed in a pattern shape, which is characterized in that transparency is imparted to the heat dissipation sheet by adopting a configuration in which the area of the heat conductive material is intentionally reduced. It is what you have.

  The heat-radiation sheet of this invention will not be specifically limited if it has a pattern-shaped heat conductive layer. Due to the difference in heat dissipation method, the preferred embodiment of the heat dissipation sheet of the present invention can be divided into two embodiments (examples). Each example will be described below.

I. 1st embodiment The heat-radiation sheet of a 1st embodiment is a member which has the space | gap part provided in the opening part of the said heat conductive layer. When the heat dissipation sheet of the first embodiment is arranged on a transparent display, a space is usually provided between the gap and the transparent display.
A heat dissipation method using the heat dissipation sheet of the first embodiment will be described with reference to the drawings. Drawing 3 (a)-(c) is an explanatory view showing an example of a heat dissipation method using a heat dissipation sheet of a first embodiment, and other examples. As shown in FIG. 3A, when the heat radiation sheet 1a of the first embodiment is arranged on the surface of the transparent display 20, heat h is conducted from the transparent display 20 to the heat conductive layer 2 in the thickness direction. The As shown in FIG. 3 (b), the heat h conducted to the heat conductive layer 2 is conducted from the central part to the outer peripheral part in the surface direction, for example, from a heat radiation part such as a casing of a transparent display. Radiated to the outside. In the heat dissipation sheet 1a of the first embodiment, the heat of the transparent display can be radiated to the outside by the heat conduction by the heat conductive layer 2.
Moreover, since the heat-radiation sheet 1a of the first embodiment has the gap portion 3, for example, as shown in FIG. 3C, the gap portion 3 is transparent when it is continuous from the center portion to the outer peripheral portion. Since a space continuous from the center to the outer periphery of the display can be provided, in addition to the heat conduction by the heat conductive layer 2, a part of the heat h of the heat conductive layer 2 is further added to the air of the gap 3 Heat h can be radiated to the outside by conducting and convection of the air in the gap 3 in the space.

  Hereinafter, each structure of the heat dissipation sheet of the first embodiment will be described.

1. Thermally conductive layer The thermally conductive layer in the first embodiment is formed in a pattern and includes a thermally conductive material.
The heat conductive layer has a function of conducting heat generated in the transparent display in the thickness direction and the surface direction. The heat conductive layer has a function of conducting heat to a heat radiating portion (for example, a housing of the transparent display, a heat radiating fin) that radiates heat to the outside of the transparent display.

The heat conductivity of the heat conductive layer is not particularly limited as long as heat can be radiated to such an extent that deterioration of the transparent display due to heat can be suppressed. The thermal conductivity in the thickness direction and the surface direction of the heat conductive layer may be the same or different. When the heat conductivity in the thickness direction and the surface direction of the heat conductive layer are different, the heat conductivity in the surface direction is preferably higher than the heat conductivity in the thickness direction.
The thermal conductivity in the surface direction of the heat conductive layer is, for example, preferably 390 W / mK or more, more preferably 400 W / mK or more, further preferably 600 W / mK or more, and 1000 W / mK. The above is particularly preferable. Further, the thermal conductivity in the surface direction of the thermal conductive layer may be, for example, 2000 W / mK or less.
On the other hand, the thermal conductivity in the thickness direction of the heat conductive layer is, for example, 0.1 W / mK or more, preferably 1 W / mK or more, and more preferably 10 W / mK or more. The heat conductivity in the thickness direction of the heat conductive layer may be, for example, 20 W / mK or less. This is because if the thermal conductivity in the thickness direction and the surface direction of the heat conductive layer is small, it may be difficult to sufficiently conduct the heat from the transparent display.
As a measuring method of thermal conductivity, it can measure by the heat flow meter method of JIS A 1412-2, for example. The thermal conductivity is a value measured at room temperature (for example, 25 ° C.).

The pattern heat conductive layer is formed in a pattern and usually has an opening. The heat-dissipating sheet usually has a pattern in which the heat conductive layer is continuously arranged from the central part to the outer peripheral part of the transparent display.

  The pattern of the heat conductive layer is not particularly limited as long as it does not hinder the transparency of the transparent display. Specifically, it may be a pattern having a pixel opening corresponding to a sub-pixel or pixel pattern of a transparent display (pixel pattern), and is a thin line pattern composed of fine lines that are not visually recognized. May be. Hereinafter, each pattern will be described.

(A) Pixel Pattern The case where the pattern of the heat conductive layer is a pixel pattern will be described.
The pixel opening pattern has a pixel opening corresponding to the sub-pixel or pixel pattern of the transparent display. “The pixel opening corresponds to the sub-pixel or pixel pattern of the transparent display” means that the shape of the pixel opening of the heat-conductive layer is in accordance with the shape of the sub-pixel or pixel of the transparent display. Say something. Here, the “pixel” is a minimum unit that constitutes an image, and is usually composed of a plurality of sub-pixels.

When the thermally conductive layer has a pixel pattern, the thermally conductive layer can be disposed along a subpixel or pixel pattern in the transparent display.
Therefore, for example, by disposing a heat conductive layer in a stripe shape between the sub-pixels, a pixel opening that is continuous from one end of the transparent display to the other end facing the sub-pixel along the width of the sub-pixel. The part can be formed. That is, since the heat conductive layer having a relatively wide width between the stripes can be disposed and the gap can be widened, heat radiation using convection of air can be performed more favorably in the gap.
In addition, for example, a region that does not hinder the transparency of the transparent display and the visibility of information can be selected, and the heat conductive layer can be disposed over a wide range. In other words, the heat conductive layer can be arranged in a wider area except for the region contributing to transparency in the transparent display. Therefore, it can be set as the thermal radiation sheet which can thermally radiate efficiently. When the heat conductive layer has a pixel pattern, it is sufficient that the heat conductive layer as a whole has transparency, and the line width of the pixel pattern may have a visible line width.

  As the pixel pattern of the thermally conductive layer, for example, as shown in FIGS. 4A and 4B, the pixel pattern has a pixel opening 3a continuously provided along the width of the sub-pixel. It may be a pattern in which a heat conductive layer is disposed between them, that is, a stripe pattern. Further, for example, as shown in FIGS. 5A and 5B, a pattern having pixel openings 3a corresponding to sub-pixels of one color and covering sub-pixels of other colors may be used. Specifically, the pixel pattern may have a pixel opening 3 a corresponding to the white subpixel W and cover the red subpixel R, the green subpixel G, and the blue subpixel B. Further, for example, as shown in FIGS. 6A and 6B, a pattern having pixel openings 3a corresponding to sub-pixels of each color and demarcating between the sub-pixels, that is, a lattice pattern may be used. good. Further, for example, as shown in FIGS. 7A and 7B, a pattern having a pixel opening 3a corresponding to one pixel including sub-pixels of each color may be used. In the case of corresponding to one pixel, the position and the number of pixel openings are adjusted so as not to disturb the transparency of the transparent display. For example, a pixel opening can be arranged for each of a plurality of pixels. 4 to 7 are schematic plan views showing one example and other examples of the pattern of the heat conductive layer in the first embodiment, and FIG. 4 (b), FIG. 5 (b), FIG. 6 (b). ) And FIG. 7B correspond to the pattern of the Y portion in FIGS. 4A, 5A, 6A, and 7A, respectively.

  In the first embodiment, the pixel pattern is preferably a lattice pattern or a stripe pattern, more preferably a stripe pattern, as described above. This is because it is possible to provide a continuous gap from the central part to the outer peripheral part of the transparent display, and it is possible to dissipate the transparent display by convection of air in the gap.

When the pixel pattern is a stripe pattern, the line width of the stripe and the width between the stripes (width of the gap) can be appropriately adjusted according to the line width of the sub-pixel, the size of the sub-pixel, and the pattern. . Examples of the shape of the stripe line include a straight line, a wavy line, and a zigzag line.
In addition, when the pixel pattern is a stripe pattern, the stripe direction is not particularly limited. For example, when the transparent display is arranged perpendicular to the ground, the end of the gap is arranged in the vertical direction. Alternatively, they may be arranged in the horizontal direction or may be arranged in the oblique direction. Among them, the stripe direction is preferably arranged in the vertical direction. This is because it is easy to radiate heat by convection of air.

  The size and shape of the pixel opening are not particularly limited, and can be appropriately selected according to the size and shape of the sub-pixel or pixel of the transparent display.

In the case of having a pixel pattern, the aperture ratio of the heat conductive layer is not particularly limited as long as desired transparency can be imparted to the heat dissipation sheet, but is preferably 20% or more, for example, 30% to 60 % Is more preferable, and a range of 40% to 50% is more preferable. This is because if the aperture ratio of the heat conductive layer is small, it may be difficult to ensure sufficient transparency of the heat dissipation sheet. On the other hand, if the aperture ratio of the heat conductive layer is large, it may be difficult to ensure sufficient heat conductivity of the heat conductive layer.
The opening ratio of the heat conductive layer is usually the ratio of the area of the opening of the heat conductive layer to the area of the entire discharge sheet.

(B) Fine line pattern The case where the pattern of a heat conductive layer is a fine line pattern is demonstrated. It may be a fine line pattern composed of lines that are not visually recognized.

  When the heat conductive layer has a fine line pattern, the heat conductive layer can be prevented from being visually recognized by an observer, and thus the transparency of the heat dissipation sheet can be further increased. Further, the transparency of the heat dissipation sheet is not affected by the sub-pixel or pixel pattern of the transparent display. Therefore, it can be set as the thermal radiation sheet which can be applied to various transparent displays. Moreover, since transparency of a heat radiating sheet can be made uniform, a heat radiating sheet can be arrange | positioned at the display surface side of a transparent display, for example.

The line width of the heat conductive layer is not particularly limited as long as it is not visually recognized by an observer. Is preferred.
This is because if the thermal conductive layer has a small line width, it may be difficult to impart sufficient thermal conductivity. If the thermal conductive layer has a large line width, it is visually recognized by an observer. This is because there is a possibility. When the line widths are different in one heat conductive layer, the maximum width is preferably within the above-described range.

  Examples of the fine line pattern include a mesh pattern.

  When the fine line pattern is a mesh pattern, the size of the mesh opening is not particularly limited as long as the desired heat conductivity can be imparted to the heat conductive layer, but may be within a range of 25 μm to 500 μm, for example. Among these, a range of 40 μm to 100 μm is more preferable, and a range of 50 μm to 80 μm is particularly preferable. This is because if the size of the mesh opening is small, it may be difficult to impart sufficient transparency to the heat dissipation sheet. On the other hand, if the size of the mesh opening is large, it may be difficult to ensure sufficient thermal conductivity. The size of the mesh opening refers to the maximum width of the mesh opening, for example, the distance indicated by p in FIG.

  Examples of the shape of the mesh opening include a triangle, a quadrangle, a hexagon, a polygon, a circle, and an ellipse.

(C) Pattern of heat conductive layer The heat conductive layer may have a connection pattern for connecting to the heat radiation part of the transparent display. Examples of the connection pattern include a pad-like pattern and a frame-like pattern that connect the casing disposed on the outer peripheral portion of the transparent display and the heat conductive layer.

(2) Thermally conductive material The thermally conductive layer includes a thermally conductive material.
The heat conductive layer should just contain the heat conductive material, may contain only a heat conductive material, and may contain the heat conductive material and the binder.

(A) When only a heat conductive material is included When the heat conductive layer contains only a heat conductive material, examples of the heat conductive material include a sheet-like metal material or a sheet-like carbon material. Can do. As a sheet-like metal material, sheets, such as aluminum, copper, and these alloys, can be mentioned, for example. On the other hand, examples of the sheet-like carbon material include a graphene sheet, a graphite sheet containing artificial graphite, or natural graphite.
When the heat conductive layer contains only the heat conductive material, the thickness of the heat conductive layer is not particularly limited as long as the heat conductive layer can be formed. For example, the thickness is within a range of 1 μm to 200 μm. Is preferably in the range of 5 μm to 50 μm, more preferably in the range of 10 μm to 20 μm.
This is because if the thickness of the heat conductive layer is thin, it may be difficult to form the heat conductive layer. If the thickness of the heat conductive layer is large, the transparent display is observed from an oblique direction. This is because it may be difficult to show sufficient transparency in some cases.

  When the heat conductive layer contains only the heat conductive material, as a method of forming the heat conductive layer, for example, the heat conductive layer is formed by punching a sheet-like heat conductive material into a desired pattern. The method of doing is mentioned. In addition, for example, there can be mentioned a method in which columnar heat conductive materials are artificially concentrated vertically on the surface of the heat dissipation sheet to form an anisotropic conductive material.

(B) When containing a heat conductive material and a binder The heat conductive layer may contain the heat conductive material and the binder. In this case, the content of the heat conductive material in the heat conductive layer is not particularly limited as long as the desired heat conductivity can be imparted. For example, the content is preferably 60% by mass or more, and 80% by mass. More preferably, it is more preferably 90% by mass or more. This is because if the content of the heat conductive material in the heat conductive layer is small, it may be difficult to impart sufficient heat conductivity to the heat conductive layer.

  The heat conductive material is not particularly limited as long as the desired heat conductivity can be imparted to the heat conductive layer. Usually, a powdery heat conductive material is used, and specifically, a powdery heat conductive material is used. Metal materials and carbon materials are used. The specific metal material can be the same as described above, and thus the description thereof is omitted here. Examples of the carbon material include graphite and carbon nanotube.

  Examples of the powdery shape of the heat conductive material include particles, spheres, needles, scales, and the like. The average particle size of the heat conductive material is not particularly limited as long as a heat conductive layer can be formed. For example, the average particle size is preferably in the range of 1 μm to 3000 μm, and preferably in the range of 10 μm to 200 μm. More preferably, it is particularly preferably in the range of 20 μm to 100 μm. The average particle diameter refers to the average particle diameter obtained by microscopic observation of the cross section of the heat conductive layer. The average particle diameter by microscopic observation is obtained, for example, by performing microscopic observation at a magnification of 100, measuring 100 particle diameters of an arbitrary powder with image processing software, and the like and averaging the number. When the particle diameter of the powder has two or more diameters having different lengths, the measured value is the longest diameter.

  Examples of the binder include a thermosetting resin and a photocuring resin.

  The thickness of the heat conductive layer is not particularly limited as long as desired heat conductivity can be imparted to the heat conductive layer. The thickness of the heat conductive layer is, for example, preferably in the range of 1 μm to 200 μm, more preferably in the range of 5 μm to 50 μm, and particularly preferably in the range of 10 μm to 20 μm. This is because if the thickness of the heat conductive layer is thin, it may be difficult to ensure sufficient heat conductivity of the heat conductive layer. This is because if the thickness of the heat conductive layer is large, the heat conductive layer may be observed when the transparent display is observed from an oblique direction.

  Examples of the method for forming a heat conductive layer include a method for forming a heat conductive layer by applying a paste containing a heat conductive material and a binder component on a support base material in a pattern. . Moreover, as a formation method of a heat conductive layer, the method of forming a heat conductive layer can be mentioned by forming a recessed part in a transparent base material and embedding a heat conductive material. In this case, you may arrange | position and pressurize a support base material.

2. Adhesion layer The heat dissipation sheet of the first embodiment may have an adhesion layer, for example.
The adhesion layer has a function of closely attaching the transparent display and the heat dissipation sheet. By bringing them into close contact with each other, it is possible to promote heat conduction from the transparent display to the heat conductive layer as compared with the case where both are arranged via air.

  As the arrangement of the adhesion layer, for example, as shown in FIG. 9A, the adhesion layer 5 may be arranged so as to be uniformly arranged on the surface of the transparent display 20 (solid). As shown in (b), the adhesion layer 5 may be formed in a pattern, but the latter is more preferable. Since it is possible to prevent the adhesion layer from being disposed in the opening of the heat conductive layer, the transparency of the heat dissipation sheet can be improved. Here, when a material containing a heat conductive filler is used as the material of the adhesion layer, the heat conductivity of the adhesion layer is increased, but the light transmissivity is decreased. This is because when the adhesion layer is formed in a pattern, the adhesion layer itself does not have to be translucent, and thus a material having high thermal conductivity can be used. In this case, the adhesion layer preferably has the same pattern as the heat conductive layer, for example. This is because the adhesion between the transparent display and the heat conductive layer can be improved.

  When the adhesion layer is formed in a pattern, for example, it may or may not have the same pattern as the thermally conductive layer, but the former is more preferable. Since the adhesion layer can be formed in the entire region of the heat conductive layer, the heat conduction from the transparent display to the heat conductive layer can be further promoted.

As an adhesion layer, it may have translucency and does not need to have translucency. When the adhesion layer is formed in a solid shape, the adhesion layer usually has translucency.
The light transmittance of the adhesion layer is, for example, 80% or more, more preferably 85% or more, and particularly preferably 90% or more.
The light transmittance of the adhesion layer can be measured by, for example, JIS K 7361-1 (a test method for the total light transmittance of a plastic-transparent material).

  The material of the adhesion layer is not particularly limited as long as the transparent display and the heat dissipation sheet can be adhered to each other. For example, a thermoplastic resin, a thermosetting resin, a photocuring resin, or the like can be used. Specifically, an acrylic resin, a urethane resin, a material provided with a functional group such as thermal polymerization property or UV photopolymerization property, or the like can be considered. As a material for the adhesion layer, for example, a commercially available pressure-sensitive adhesive or adhesive can be used.

  In the first embodiment, a heat conductive filler may be added to such an extent that the adhesion of the adhesion layer is not impaired. Examples of the heat conductive filler include the above-described particulate heat conductive material.

  The thickness of the adhesion layer can be appropriately selected according to the transparent display, and is not particularly limited. For example, the thickness is preferably in the range of 0.1 μm to 200 μm, and more preferably in the range of 1 μm to 10 μm. More preferably, it is particularly preferably in the range of 2 μm to 5 μm. This is because if the thickness of the adhesion layer is thin, it may be difficult to sufficiently adhere the transparent display and the heat conductive layer. On the other hand, if the thickness of the adhesion layer is large, there is a possibility that heat conduction from the transparent display to the heat conductive layer may be hindered. Moreover, it is because the transparency of a transparent display may fall.

  The adhesion layer only needs to be formed on the heat conductive layer, may be formed directly on the heat conductive layer, or may be formed through another layer, but the former is more preferable. . This is because heat conduction can be performed directly from the adhesion layer to the heat conductive layer.

  Examples of the method for forming the adhesion layer include a method in which an adhesion layer such as an adhesive sheet is separately prepared and bonded to the heat conductive layer. In addition, a laminate of a sheet-like adhesion layer and a heat conductive layer can be punched into a pattern. Moreover, it can form by apply | coating the material of an adhesion layer on a heat conductive layer.

3. Support base material The heat dissipation sheet of the first embodiment may have a support base material 6 as shown in FIG. The support substrate supports the heat conductive layer and functions as a protective layer for the heat conductive layer.

  As a support base material, it usually has translucency. The light transmittance of the support substrate is not particularly limited as long as it does not interfere with the transparency of the transparent display and the heat-dissipating sheet. For example, it has a light transmittance comparable to the light transmittance of the adhesion layer described above. Is preferred.

As the support substrate, for example, a translucent substrate can be used. As a translucent board | substrate, a glass base material and a resin base material can be mentioned, for example.
The thickness of the supporting substrate can be appropriately selected according to the transparent display, and is not particularly limited, but is preferably in the range of 10 μm to 300 μm, for example.

4). Reinforcing layer The heat-dissipating sheet of the first embodiment may further have a reinforcing layer 7 as shown in FIG. The reinforcing layer has a function of increasing the strength of the heat conductive layer. This is because heat transfer from the heat conductive layer to air can be facilitated when the heat conductive layer includes a metal material.

  For example, as shown in FIG. 11, the reinforcing layer is formed so as to seal the heat conductive layer 2. Specifically, the reinforcing layer 7 is preferably formed so as to cover the surface and side surfaces of the heat conductive layer 2.

  Examples of the material for the reinforcing layer include a thermosetting resin and a photocurable resin.

The thickness of the reinforcing layer is not particularly limited as long as the heat conductive layer can be reinforced. For example, the thickness is preferably in the range of 0.1 μm to 200 μm, and more preferably in the range of 1 μm to 10 μm. More preferably, it is particularly preferably in the range of 2 μm to 5 μm.
Moreover, when a heat-radiation sheet has a reinforcement layer, a support base material may be used together and it is not necessary to use together, but the latter is more preferable. Moreover, when a heat dissipation sheet has a reinforcement layer, it is preferable that a heat conductive material contains a carbon material from a viewpoint of raising the intensity | strength of a heat conductive layer. Carbon materials generally tend to have lower strength than metal materials. For this reason, the use of the heat conductive layer containing the carbon material and the reinforcing layer can enhance the function of the reinforcing layer.

  Examples of the method of forming the reinforcing layer include a method of forming the reinforcing layer by applying a material of the reinforcing layer to the surface of the heat conductive layer.

5. Heat dissipation fan The heat dissipation sheet of the first embodiment may further include a heat dissipation fan. The heat dissipating fan is arranged on the outer peripheral portion of the heat dissipating sheet, thereby having a function of convection of the air in the gap. The position of the heat radiating fan is not particularly limited. For example, when the transparent display is arranged perpendicular to the ground, it is preferably arranged at the upper end.

II. Second Embodiment The heat dissipation sheet of the first embodiment further has a heat absorption layer filled in the opening of the heat conductive layer.
A heat dissipation method using the heat dissipation sheet of the second embodiment will be described with reference to the drawings. FIGS. 12A and 12B are explanatory views showing an example of a heat dissipation method using the heat dissipation sheet of the second embodiment and another example. As shown to Fig.12 (a), when the thermal radiation sheet 1a of a 2nd embodiment is arrange | positioned on the surface of the transparent display 20, in the thickness direction, the heat conductive layer 2 and the heat absorption layer 4 from the transparent display 20 are shown. Heat h1, h2 is conducted. As shown in FIG. 12 (b), the heat h1 conducted to the heat conductive layer 2 is conducted from the central part to the outer peripheral part in the surface direction, for example, from a heat radiation part such as a casing of a transparent display. Radiated. On the other hand, the heat h2 conducted to the heat absorption layer 4 is conducted from the heat absorption layer 4 to the heat conductive layer 2, and is released to the outside through the heat conductive layer 2. In the heat dissipation sheet of the second embodiment, heat can be prevented from being accumulated inside the transparent display by allowing the heat absorption layer to absorb the heat of the transparent display.

  Hereinafter, the configuration of the heat dissipation sheet of the second aspect will be described.

1. Heat absorption layer The heat absorption layer in a 2nd aspect is a thing filled with the opening part of the heat conductive layer.
The heat dissipation sheet of the second embodiment may have a heat absorption layer. The heat absorption layer has a function of absorbing (accumulating) heat from the transparent display. The heat absorption layer has a function of conducting the absorbed heat to the heat conductive layer.

  The arrangement of the heat absorption layer is not particularly limited as long as the heat from the transparent display can be absorbed and the absorbed heat can be conducted to the heat conductive layer. For example, as shown in FIGS. Moreover, it is preferable that the heat absorption layer 4 is formed in the opening of the heat conductive layer 2. In this case, it is preferable that at least a part of the heat conductive layer and the heat absorption layer are in close contact with each other. This is because heat from the transparent display can be suitably discharged by forming the heat absorption layer in the opening of the heat conductive layer.

  The heat absorption layer usually has translucency. The light transmittance of the heat absorption layer can be appropriately selected according to the transparent display, and is not particularly limited. For example, the light transmittance of the heat absorption layer preferably has the same light transmittance as that of the heat absorption layer described above. .

  The material of the heat absorption layer is not particularly limited as long as it does not hinder the transparency of the transparent display. Examples of the material of the heat absorption layer include a thermoplastic resin, a thermosetting resin, and a photocurable resin. Specifically, an acrylic resin, a urethane resin, a material provided with a functional group such as thermal polymerization property or UV photopolymerization property, or the like can be considered.

  The thickness of the heat absorption layer is not particularly limited as long as the heat from the transparent display can be absorbed and conducted to the heat conductive layer. The thickness of the heat absorption layer is, for example, preferably in the range of 1 μm to 200 μm, more preferably in the range of 5 μm to 50 μm, and particularly preferably in the range of 10 μm to 20 μm. This is because if the thickness of the heat absorption layer is thin, it may be difficult to form the heat absorption layer. This is because if the thickness of the heat absorption layer is large, the heat conductivity of the heat conductive layer may be hindered.

  As shown in FIGS. 13B and 13C, the heat absorption layer 4 may also serve as an adhesion layer. Moreover, as shown in FIG.13 (c), the heat absorption layer 4 may be formed so that the surface of the heat conductive layer 2 may be covered. In this case, the heat absorption layer 4 also functions as a protective layer for the heat conductive layer 2.

  Examples of the method of forming the heat absorption layer include a method of forming the heat absorption layer by filling the opening of the heat conductive layer with the material of the heat absorption layer.

2. Thermally conductive layer The thermally conductive layer used in the second embodiment will be described.
The pattern of the heat conductive layer in the second embodiment is not particularly limited as long as it does not hinder the transparency of the transparent display, and may be a pixel pattern or a fine line pattern. In the second embodiment, in particular, a pixel pattern can be preferably used, and in particular, a pattern having a pixel opening corresponding to a sub-pixel of one color and covering a sub-pixel of another color. Is preferred. Moreover, when a transparent display has a white subpixel, it is preferable to have a pixel opening corresponding to the white subpixel. This is because the heat conductive layer can be arranged in a wide area while maintaining the transparency of the transparent display, and thus the heat of the transparent display can be radiated more favorably. This is because the pixel pattern can widen the area of the conductive layer, so that the heat from the heat absorption layer can be efficiently radiated to the outside of the transparent display.
Since matters other than those described above for the thermally conductive layer can be the same as those described in the first embodiment, description thereof is omitted here.

3. Adhesive layer The adhesive layer used in the second embodiment will be described.
In the second embodiment, the adhesion layer 5 may be arranged so as to be uniformly arranged (solid) on the surface of the transparent display, or the adhesion layer may be formed in a pattern, but the former Is more preferable. When the adhesion layer is arranged in a solid shape, the adhesion between the transparent display and the heat dissipation sheet can be increased. In addition, heat conduction from the transparent display to the heat absorption layer can be favorably performed.

  As the material for the adhesion layer in the second embodiment, a material having translucency is usually used. Regarding the adhesive layer, matters other than those described above can be the same as those described in the section of the first embodiment, and thus description thereof is omitted here.

4). Support base material The heat dissipation sheet of the second embodiment may further have a support base material. About a support base material, since it can be set as the content demonstrated by the term of the 1st embodiment mentioned above, description here is abbreviate | omitted.

III. Heat dissipation sheet The heat dissipation sheet of the present invention is used for a transparent display. The heat dissipation sheet can conduct heat from the central portion of the transparent display to the outer peripheral portion. The heat dissipation sheet of the present invention is usually disposed on the outer surface of a transparent display panel.

The transparent display may be a display whose information can be viewed only from one side (single-sided display), or a display whose information can be viewed from both sides (double-sided display).
Examples of the transparent display include a liquid crystal display and an organic electroluminescence (organic EL) display.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

DESCRIPTION OF SYMBOLS 1 ... Heat dissipation sheet 2 ... Thermally conductive layer 3 ... Gap part 4 ... Heat absorption layer 5 ... Adhesion layer

Claims (5)

A heat dissipation sheet used for a transparent display,
A heat dissipating sheet having a heat conductive layer formed in a pattern and containing a heat conductive material.   The heat dissipation sheet according to claim 1, further comprising a gap provided in an opening of the heat conductive layer.   The heat-radiating sheet according to claim 1, further comprising a heat absorption layer filled in the opening of the heat conductive layer.   The pattern of the said heat conductive layer is the pattern for pixels which has the opening part for pixels corresponding to the subpixel of the said transparent display, or the pattern of a pixel, The Claim 1 characterized by the above-mentioned The heat dissipation sheet according to claim.   The heat dissipation sheet according to any one of claims 1 to 4, further comprising an adhesion layer that closely contacts the transparent display and the heat dissipation sheet.

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