JP2011228585A - Heat dissipation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high heat dissipation performance without notably changing an external dimension (appearance) of a heat dissipation structure.SOLUTION: The heat dissipation structure includes a heat conduction layer 1 and an inner layer 2 provided on an inside of the heat conduction layer 1 and having a three-dimensional shape imparting layer on an innermost face-side. In the heat conduction layer 1, a heat conductivity in at least one direction in the layer is 2 W/m K or above, an average thickness is 0.2 to 5 mm and a product of the heat conductivity and the average thickness is 0.01 W/K or above. In the three-dimensional shape imparting layer, a plurality of uneven portions, which have an average valley width of 1 to 20 mm, an average ridge width of 0.5 to 5 mm and an average height that is 1 to 10 times as much as the average valley width, are arranged to be brought into contact with at least a part of a heating unit in 10% or above region of the inner layer. A surface area of a region where the three-dimensional imparting layer is disposed is 1.2 times as much as a case of a flat surface without the uneven portion.

Description

  The present invention includes a light emitting element (LED element, laser diode, EL element, etc.), active light receiving element (CCD, etc.), central processing unit (CPU), image arithmetic unit (MPU), inverter element (IGBT, FET, etc.), motor The present invention relates to a heat dissipation structure that is used as a heat dissipation measure for devices, appliances, and the like in which devices that generate heat such as heaters and heater elements are mounted.

  In recent years, a large number of devices with high heat generation density (LED elements, laser diodes, CPUs, MPUs, etc.) have been mounted in electronic / electrical equipment, and temperature control for ensuring high reliability in driving these devices, that is, Heat dissipation measures are becoming extremely important.

  These heat dissipation measures include heat dissipation structures (fin-type heat sinks, etc.) formed by molding metals with high thermal conductivity (copper, aluminum, aluminum alloy, magnesium alloy, etc.) using extrusion molding, die casting, etc. ) In the vicinity of the heat generation source, it is common to design a route that efficiently dissipates heat to the outside air. (For example, Patent Documents 1 to 3)

Japanese Patent Application Laid-Open No. 07-159012 JP-A-10-092986 JP 2004-071599 A

  These conventional heat dissipation measures increase the external dimensions and volume due to the arrangement of protrusions on the outer surface of the heat dissipation structure in order to achieve high heat dissipation performance. In order to meet market demands such as design, etc., higher heat dissipation performance is required. In view of these circumstances, the present invention has been made with the object of realizing extremely high heat dissipation performance without significantly changing the outer dimension (appearance) of the heat dissipator.

  The present invention is a heat dissipation structure including a heat conductive layer and an endothelial layer provided on the innermost surface and having a three-dimensional shape shaping layer on the innermost surface side. The heat conductive layer is at least one of the layers. The thermal conductivity in the direction is 2 W / m · K or more, the average thickness is 0.2 to 5 mm, the product of the thermal conductivity and the average thickness is 0.01 W / K or more, and the three-dimensional shape shaping layer is A plurality of uneven portions exist in an area of 10% or more of the endothelial layer, the average valley width of the uneven portion is 1 to 20 mm, the average peak width is 0.5 to 5 mm, and the average height is 1 to 10 times the average valley width. And the surface area of the region in which the three-dimensional shape shaping layer is provided so as to be in contact with at least a part of the heating element is 1.2 times or more compared to a flat surface without an uneven portion. It is a heat dissipation structure characterized by being.

  The heat dissipating structure of the present invention can achieve extremely high heat dissipating performance without significant changes in the external dimensions and appearance of the heat dissipating structure, and is particularly suitable for heat dissipating measures for devices with dimensional restrictions.

An example of the heat dissipation structure of the present invention (a cross-sectional view seen from the top and front) Explanatory drawing about each part dimension of the uneven | corrugated | grooved part shape of the three-dimensional shape shaping layer in the thermal radiation structure of this invention (sectional drawing seen from the upper surface) An example of the contact portion between the heat dissipation structure and the heating element of the present invention (cross-sectional view as seen from the front) Application example of the heat dissipating structure of the present invention to an LED illuminator (when the interior of the illuminator is an air layer) (cross-sectional view seen from the front) Application example of the heat dissipating structure of the present invention to an LED illuminator (when there is an electrical insulating layer component inside the illuminator) (cross-sectional view seen from the front) An example of the uneven portion shape of the three-dimensional shape shaping layer in the heat dissipation structure of the present invention (cross-sectional to perspective view) An example of the uneven portion shape of the three-dimensional shape shaping layer in the heat dissipation structure of the present invention (cross-sectional view seen from the top, front, and side) An example of the uneven portion shape of the three-dimensional shape shaping layer in the heat dissipation structure of the present invention (cross-sectional to perspective view) An example of the uneven portion shape of the three-dimensional shape shaping layer in the heat dissipation structure of the present invention (cross-sectional view seen from the top, front, and side) An example of the concavo-convex shape of the three-dimensional shape shaping layer in the heat dissipation structure of the present invention (cross-sectional view seen from the top and front) An example of the concavo-convex shape of the three-dimensional shape shaping layer in the heat dissipation structure of the present invention (cross-sectional view seen from the top and front) An example of the uneven portion shape of the three-dimensional shape shaping layer in the heat dissipation structure of the present invention (cross-sectional view seen from the top, front, and side) An example of the uneven portion shape of the three-dimensional shape shaping layer in the heat dissipation structure of the present invention (cross-sectional view seen from the top, front, and side) An example of the uneven portion shape of the three-dimensional shape shaping layer in the heat dissipation structure of the present invention (cross-sectional view seen from the top, front, and side) An example of the heat dissipation structure of the present invention (a cross-sectional view seen from the top and front) An example of the heat dissipation structure of the present invention (a cross-sectional view seen from the top and front) An example of the heat dissipation structure of the present invention (a cross-sectional view seen from the top and front) Explanatory drawing about the dimensions of each part of the heat dissipation structure of the present invention (cross-sectional view seen from the front)

  The present invention is a heat dissipating structure including a heat conductive layer and an endothelial layer provided on the inner side and having a three-dimensional shape shaping layer on the innermost surface side. Hereinafter, embodiments of the present invention will be described in detail.

[Heat dissipation structure]
At least a part of the heat dissipating structure of the present invention is disposed in the vicinity of the heat generating element, and after the heat of the heat generating element is transferred from the contact surface, the heat is transported through the heat dissipating structure, and finally the outermost part of the heat dissipating structure. It is a structure having a function of dissipating heat from the outer layer to outside air or the like. In the case of using the LED element heat dissipation component which is a preferred embodiment of the heat dissipation structure of the present invention, the amount of heat once dissipated from the LED substrate side into the housing and the amount of heat dissipated from the internal power supply substrate into the housing are described. Through the heat dissipation structure of the present invention, heat is transferred to the heat dissipation housing to promote heat dissipation.

  The heat dissipation structure of the present invention includes a heat conductive layer and an inner skin layer provided on the inner side, and the inner skin layer has a three-dimensional shape shaping layer on the innermost surface side. The thermal conductivity layer has a thermal conductivity of 2 W / m · K or more in at least one direction in the layer, an average thickness of 0.2 to 5 mm, and a product of the thermal conductivity and the average thickness of 0.01 W / K or more. It is. The three-dimensional shape-imparting layer has a plurality of uneven portions in an area of 10% or more of the endothelial layer, the average valley width of the uneven portions is 1 to 20 mm, the average peak width is 0.5 to 5 mm, and the average height is average. It is 1 to 10 times the valley width, and is arranged so as to be in contact with at least a part of the heating element. The surface area of the region where the three-dimensional shape shaping layer is provided is 1.2 times or more compared to the case where the surface is a flat surface having no irregularities.

[Three-dimensional shape shaping layer]
The three-dimensional shape shaping layer in the heat dissipating structure of the present invention increases the surface area of the innermost surface of the heat dissipating structure, and increases the contact area with the air layer or equipment component inside the heat dissipating structure, and further with the heat generating element. It is formed for the purpose of enhancing the heat transfer property at the interface between the innermost surface of the structure and the internal air layer or equipment component, and further the heating element. As an example, the case where the heat dissipation structure of the present invention is used as a heat dissipation component of an LED element in an LED lighting device will be described. From the viewpoint of promoting heat dissipation of the LED element, It is important to improve the heat transfer between the component parts such as the air layer or the electrical insulating layer inside the lighting fixture, and the LED element mounting substrate serving as a heating element and the heat dissipation structure. Since these heat transfer properties greatly depend on the contact area between the heat transfer surfaces, it is preferable to increase the contact area as much as possible.

  Due to the formation of the three-dimensional shape shaping layer, the surface area of the endothelial layer is 1.2 times or more, preferably 2 times or more, more preferably 3 times or more, compared to the case of a flat surface, The upper limit is not particularly limited if it is a possible shape.

  The increase ratio of the surface area of the endothelial layer is determined by the shape, size, formation density, and the like of the concavo-convex portion formed as the three-dimensional shape shaping layer. That is, the main control factors are the valley width of the concave portion, the peak width of the convex portion, the height of the convex portion, the curvature of the concave and convex portion (when a curved surface is arranged in whole or in part), and the like.

  The three-dimensional surface shaping layer in the present invention has a plurality of uneven portions, but the shape of the uneven portions is one in which the uneven portions are continuously formed one-dimensionally, or the uneven portions are What is formed discontinuously is mentioned. The pitch of the uneven portions may be constant or variable, and may be selected according to the shape of the heat dissipation structure to be obtained. The height, size, and the like of the convex portion may be constant or variable, and can be selected according to the shape of the heat dissipation structure to be obtained.

  The present invention is characterized in that the heat dissipation is enhanced by controlling the shape inside the heat dissipation structure so that there is no significant change in the outer dimension (appearance) of the heat dissipation structure, and the shape restriction inside the heat dissipation structure is allowed. The shape of the concavo-convex portion can be selected freely to some extent within the range, but is arranged so as to be in contact with at least a part of the heating element.

  The three-dimensional shape-imparting layer has a plurality of uneven portions in an area of 10% or more of the endothelial layer, the average valley width of the uneven portions is 1 to 20 mm, the average peak width is 0.5 to 5 mm, and the average height is average. 1 to 10 times the valley width.

  In order to realize high heat dissipation performance, the average valley width of the recesses is 1 to 20 mm, preferably 2 to 10 mm, and more preferably 3 to 5 mm. When the average valley width of the recess is less than 1 mm, the heat transfer with the internal air layer does not cause sufficient air convection because the recess is too narrow. Since sufficient contact at the interface is difficult, the heat dissipation efficiency deteriorates. On the other hand, when the thickness exceeds 20 mm, the surface area of the endothelial layer of the heat dissipation structure is not sufficiently large, and heat transfer with the air layer or device components becomes insufficient. As will be described later, the shape pattern of the recess is not particularly limited, and various shapes are possible. In that case, for example, when the valley width of the concave portion changes continuously, such as when the cross-sectional shape of the concave and convex portions is a continuous triangle or semicircular shape and there is no flat portion at the bottom, the average value of the valley width of the concave portion is averaged. The valley width.

  In the three-dimensional shape shaping layer of the present invention, the average peak width of the convex portions is 0.5 to 5 mm, preferably 0.8 to 4 mm, and more preferably 1 to 3 mm. When the average peak width of the convex portion is less than 0.5 mm, heat transfer is not sufficiently performed to the tip of the convex portion, and the contact area with the heating element is not sufficiently large, resulting in poor heat dissipation efficiency. On the other hand, when the thickness exceeds 5 mm, the surface area of the endothelial layer of the heat dissipating structure is not sufficiently large, and heat transfer with the air layer or device components becomes insufficient.

  In the three-dimensional shape shaping layer of the present invention, the average height of the convex portions is 1 to 10 times the average valley width of the concave portions, preferably 2 to 8 times, and more preferably 3 to 6 times. If the average height of the protrusions is less than one times the average valley width of the recesses, the surface area of the endothelial layer of the heat dissipation structure may not be sufficiently large, and heat transfer with the air layer or device components may be insufficient. is there. Further, the contact area with the heating element is not sufficiently large, and the heat dissipation efficiency is deteriorated. On the other hand, if it exceeds 10 times, sufficient air convection is unlikely to occur in the recess, resulting in poor heat dissipation efficiency. As will be described later, the shape pattern of the convex portion is not particularly limited, and various shapes are possible. At that time, for example, when the peak width of the convex portion such as the protrusion cross-sectional shape is triangular or semicircular continuously changes, the average peak width of the convex portion is defined as the average peak width.

  There are no particular limitations on the shape and arrangement pattern of the concavo-convex portions forming the three-dimensional shape shaping layer, and various shapes and arrangements are possible. The concave and convex portions may be continuously continuous or may be a single protrusion, but shapes and arrangement patterns that increase the contact area with the heating element are preferable. In the former case, the arrangement direction may be any direction on the surface of the heat dissipation structure, and may be arranged in a straight line or a curved line. In the latter case, they may be arranged with a certain regularity such as a cylindrical shape, a hemispherical shape, a polygonal shape, etc., or may be arranged randomly without any regularity. Furthermore, the height, peak width, and valley width dimensions of the concavo-convex portion may be continuously changed.

To give more specific examples, FIGS. 6, 7, 8, 9, 10, and 11 are uneven portions in which the shape of the uneven portion forming the three-dimensional shape shaping is continuous, In this example, the concavo-convex portions are arranged in a shape extending in a direction parallel to the axial direction of the cylindrical or conical heat dissipation structure. Of these, FIGS. 6, 7, and 10 are examples in which the height of the concavo-convex portion is constant, FIGS. 8 and 9 are examples in which the concavo-convex portion is arranged in a part of the endothelial layer, and FIG. This is an example in which the height of the uneven portion is continuously changed.
In addition, FIGS. 12, 13, and 14 are examples in which the single protrusion-shaped uneven portions are arranged in a cylindrical shape, a hemispherical shape, and a polygonal shape.

The three-dimensional shape shaping layer is formed in a region of 10% or more on the innermost surface side of the endothelial layer. If it is less than 10%, the effect of increasing the surface area of the heat dissipation structure tends to be insufficient. It is preferably formed in a region of 30% or more of the innermost surface, more preferably 50% or more.
Since the three-dimensional shape-imparting layer is a part of the endothelial layer which will be described in detail later, preferred materials and the like will be described in the column of the endothelial layer.

  As a preferable method for providing the three-dimensional shape shaping layer, in view of production efficiency, it is preferable to carry out shape marking on the inner surface of the mold, such as injection molding, die casting, etc., but after the molding, Implementation by post-processing is also possible, for example, a method of pressing the mold surface with the shape marking for surface molding applied to the molded product and performing surface molding by hot pressing, or surface molding was performed in advance. Examples thereof include a method of adhering a resin to the surface of a molded product, a method of cutting a molded product that has been prepared in advance, and the like.

[Endothelial layer]
The endothelium layer in the heat dissipation structure of the present invention includes a three-dimensional shape shaping layer, a portion excluding the protruding portion constituting the three-dimensional shape, and a portion not having the three-dimensional shape is a base layer. The endothelium layer is more preferably a layer having high thermal conductivity, preferably a layer having high thermal conductivity in order to efficiently release heat received from the internal air layer of the heat dissipation structure, device components, and the heating element to external air or the like. The thermal conductivity in at least one direction is preferably 2 W / m · K or more. More preferably, it is 5 W / m * K or more, More preferably, it is 15 W / m * K or more. As in the example of FIG. 15, it is also preferable that the endothelial layer is made of the same material as the heat conductive layer. In that case, it is preferable that the endothelial layer and the heat conductive layer are integrally formed.

  The thickness of the base layer is preferably constant in the heat dissipation structure from the viewpoint of ease of molding and the like. When the base layer thickness of the endothelium layer is small, specifically, when the base layer thickness is 2 mm or less, heat transfer loss (temperature difference generation) can be relatively small, so that the thermal conductivity is 2 W / m · Even a layer of less than K may be used as an endothelial layer. The base layer thickness is more preferably 1.5 mm or less, and still more preferably 1.0 mm or less.

In particular, by forming the endothelial layer from a material having high electrical insulation (particularly, a layer having a volume resistance of 10 ⁹ cm · Ω or more, more preferably a layer having a volume resistance of 10 ¹² cm · Ω or more), It is preferably used according to the application because the physical safety is increased (increased withstand voltage and electrostatic withstand voltage, reduced leakage current, etc.).

  The endothelium layer preferably contains a thermally conductive filler and is made of a thermally conductive resin composition having a thermal conductivity of at least 2 W / m · K in at least one direction in the layer. The preferable aspect of a heat conductive filler and a heat conductive resin composition is mentioned later.

[Heat dissipation structure and 3D shape shaping layer]
At least a part of the heat dissipating structure of the present invention is disposed in the vicinity of the heat generating element, and after the heat of the heat generating element is transferred from the contact surface, the heat is transported through the heat dissipating structure, and finally the outermost part of the heat dissipating structure is obtained. It is a structure having a function of dissipating heat from the outer layer to outside air or the like.

  Examples of the heat dissipation structure are illustrated in FIGS. In the figure, symbol 2 indicates an endothelial layer including a three-dimensional shape shaping layer. In each of these examples, the shape is based on a cylindrical structure, but the heat dissipation structure of the present invention is not limited to these illustrated shapes, and is a polygonal column, cone, polygonal pyramid, or more complicated. It may be based on a tertiary cubic shape.

  The heat transport capability of the heat dissipation structure can be generally expressed by the product of its average thickness (average thickness in the direction perpendicular to the direction of heat flow, unit m) and thermal conductivity (unit W / m · K). The value is preferably 0.01 W / K or more, and if it is less than that, heat transfer of the heating element tends to be insufficient in many applications. The product of thermal conductivity and average thickness is more preferably 0.03 W / K or more, and still more preferably 0.05 W / K or more. When the material of the heat conduction layer of the heat dissipation structure and the base layer in the endothelium layer are different, the thermal conductivity is a parallel composite value considering the thickness, and the average thickness is the sum of the average thicknesses of both layers. Calculate

  When a part of the heat dissipation structure is placed in contact with the heat generating element to be dissipated and the function of transporting the heat transferred from the heat generating element to the outermost layer is required, the heat dissipation structure can conduct heat in at least one direction of the layer. The rate is preferably 2 W / m · K or more, and the average thickness is preferably 0.2 to 5 mm. If the thermal conductivity is less than 2 W / m · K, it is necessary to increase the thickness of the heat dissipating structure, which unnecessarily increases the overall dimensions. The thermal conductivity is more preferably 5 W / m · K or more, and still more preferably 15 W / m · K or more. The average thickness of the heat dissipation structure is preferably as small as possible in consideration of the amount of heat transport required for each application from the viewpoint of reducing the overall dimensions. However, if it is less than 0.2 mm, the mechanical strength often decreases, more preferably 0.5 to 4 mm, and still more preferably 1 to 3 mm.

  The heat dissipating structure of the present invention is preferably integrally molded from a single material, and particularly produced with good productivity by die molding (particularly injection molding, die casting) using a die having a three-dimensional shape engraved on the inner surface. However, if necessary, only the endothelial layer including the three-dimensional shape shaping layer may be molded from different materials and integrated. As a method for integration, a method by insert molding, adhesion by a heat conductive adhesive, or the like is preferable.

In addition, the outermost layer of the heat dissipation structure can be provided with an electrical insulating layer as necessary as illustrated in FIG. 16 or an uneven portion as illustrated in FIG. By forming the outermost layer from a material having high electrical insulation (particularly, a layer having a volume resistance of 10 ¹¹ cm · Ω or more, more preferably a layer having a volume resistance of 10 ¹³ cm · Ω or more), Since safety is increased (insulation breakdown voltage, increase in electrostatic breakdown voltage, reduction of leakage current, etc.), it is preferably used according to the application. Further, the electrical insulating layer is more preferably a layer having high thermal conductivity, and preferably has a thermal conductivity of at least 0.5 W / m · K in one direction in the layer, more preferably 1 W / m · K or more.

  By forming an uneven portion similar to the inner skin layer of the present invention in the outermost layer of the heat dissipation structure, the heat dissipation performance of the heat dissipation structure can be further enhanced. In this case, unlike the endothelial layer, the outer dimension (appearance) of the heat dissipation structure changes, so that it is preferable to carry out within the allowable range of the appearance shape constraint.

[Thermal conduction layer]
The heat conduction layer is arranged so that a part of the heat radiating structure is in contact with a heat generating body (heat generation source) that should radiate heat and controls the function of transporting the heat transferred from the heat generating element to the outermost layer. The heat conduction layer has a heat conductivity of 2 W / m · K or more in at least one direction in the layer and an average thickness of 0.2 to 5 mm. The product of thickness is 0.01 W / K or more.

  The thermal conductivity of the heat conductive layer is more preferably 5 W / m · K or more, still more preferably 15 W / m · K or more, and the average thickness is more preferably 0.5 to 4 mm, still more preferably 1 to 3 mm. It is.

  Specific examples of suitable materials for the heat conductive layer include metals such as copper, silver, aluminum, iron, stainless steel, zinc, titanium, silicon, and chromium, and alloys of these metals. The heat conductive layer made of these metals or alloys can be formed by a casting method, a forging method, a cutting process of a block-shaped metal lump or the like. Examples of the casting method include a die casting method in which molding is performed while applying a compressive force in a mold, and a method in which casting is performed by simply pouring into a die and natural cooling. As the forging method, a cold forging method in which ductile processing is performed by applying shear stress to the heated metal layer is preferably exemplified.

  In particular, copper, silver, aluminum, silicon and metal alloys based on them often have a thermal conductivity of 50 W / m · K or more, and satisfy the high heat transport capability required as a heat conductive layer Can be used preferably. The thermal conductivity of the heat conductive layer made of metal alloys is more preferably 75 W / m · K or more, and still more preferably 100 W / m · K or more.

  However, when these metals and metal alloys are used for the heat conductive layer, the overall weight of the heat dissipation structure is increased, which may not be preferable for use. In addition, when a metal with high conductivity is used for the heat conduction layer, leakage currents and induced currents from various devices and power supply wiring lines mounted on equipment and appliances may increase. Since a large amount of current flows into the heat conduction layer when an unexpected short circuit of the power supply wiring line occurs, there may be a concern about safety as a device or instrument.

In applications in which importance is placed on ensuring lightweight and electrical safety, it is preferable to use a layer having as large an electrical resistance (volume resistance) as the heat conduction layer, and the volume resistance of the layer is 1 × 10 ⁻² Ω · It is more preferable that it is cm or more, more preferably 1 × 10 ⁰ Ω · cm or more, and further preferably 1 × 10 ⁴ Ω · cm or more.

  As a heat conductive layer satisfying these requirements, various heat conductive fillers are combined, and a heat conductive resin composition having a heat conductivity of at least 2 W / m · K in at least one direction in the layer is molded. Are particularly preferably used. The thermal conductivity is more preferably 5 W / m · K or more, and still more preferably 15 W / m · K or more.

  The layer having such a high thermal conductivity and excellent three-dimensional shape moldability (precise transferability) is formed by molding a heat conductive resin composition containing pitch-based graphitized carbon short fibers described later. Preferred is a layer.

  The heat conductive layer formed using these heat conductive resin compositions has a low specific gravity and light weight compared to the case of using the above metals and metal alloys, and can be formed with high accuracy. The electrical resistance is higher than that of metals and metal alloys, and the above-mentioned suitable volume resistance can be realized. Therefore, the lightness of devices and instruments, drop safety, design, compatibility with other components, electrical safety It has characteristics such as sex.

[Thermal conductive resin composition]
As a heat conductive resin composition suitable for molding the heat conductive layer or the endothelial layer of the heat dissipation structure of the present invention, the content of the heat conductive filler is 10 to 200 parts by volume with respect to 100 parts by volume of the matrix resin. A resin composition is preferred. When the content of the heat conductive filler is less than 10 parts by volume, it is difficult to obtain high heat conductivity. On the other hand, if the content of the heat conductive filler exceeds 200 parts by volume, it is difficult to disperse the heat conductive filler in the resin and obtain a uniform heat conductive resin composition, and the fluidity of the resin is low. It tends to be insufficient. The content of the heat conductive filler is preferably 20 to 100 parts by volume.

The heat conductive filler and the matrix resin can be mixed using a known melt kneader such as a uniaxial melt kneader or a biaxial melt kneader.
Thermally conductive fillers include metal oxides such as aluminum oxide, magnesium oxide, silicon oxide and zinc oxide, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, metal nitrides such as boron nitride and aluminum nitride, oxidation Metal oxynitrides such as aluminum nitride, metal carbides such as silicon carbide, metals or metal alloys such as gold, silver, copper, and aluminum, carbon materials such as carbon fiber, natural graphite, artificial graphite, expanded graphite, and diamond Two or more types can be used in combination.

  Pitch-based graphitized short fibers are preferably used to increase the thermal conductivity of the heat conductive resin composition. Among them, pitch-based graphitized short fibers having a very developed graphite crystal structure starting from mesophase pitch are used. It is particularly preferred. In other words, the thermal conductivity of graphitized short fibers is mainly derived from the phonon vibration that propagates through the lattice structure of the graphite crystal. Therefore, to increase the thermal conductivity, the crystallinity of the graphite crystal is increased. It is preferable that the number of defects is as small as possible and widened.

  The pitch-based graphitized short fibers used in the present invention correspond to so-called milled fibers, and the average fiber length (L1) is more preferably 20 to 500 μm. Here, the average fiber length is a number average fiber length, a predetermined number is measured under a microscope, and can be obtained from the average value. When L1 is smaller than 20 μm, the short fibers are less likely to contact each other, and it may be difficult to obtain a thermally conductive composition having high thermal conductivity. On the other hand, when L1 is larger than 500 μm, the viscosity at the time of kneading the matrix resin and pitch-based graphitized short fibers becomes high, and handling may be difficult. More preferably, it is the range of 30-300 micrometers. There is no particular limitation on the method for obtaining such pitch-based graphitized short fibers, but a crushing machine such as a cutting type, a collision type, an impact type, and an airflow type is preferably used, and the rotational speed, residence time, airflow ejection pressure, The average fiber length can be controlled by adjusting conditions such as the supply amount. In addition, the pitch-based carbon short fibers after pulverization are subjected to classification operations such as vibration, sieving with a screen, centrifugal separation, etc. to remove short fiber lengths or pitch-based carbon short fibers having a long fiber length. Further, the average fiber length can be controlled more precisely.

  The pitch-based graphitized short fibers used in the present invention are composed of graphite crystals, and the crystallite size derived from the hexagonal network surface growth direction is preferably at least 20 nm or more, more preferably 30 nm or more, and even more preferably 40 nm. That's it. The crystallite size corresponds to the degree of graphitization (crystallinity of the graphite crystal) in any of the growth directions of the hexagonal network surface, and a certain size or more is necessary to exhibit thermophysical properties. The crystallite size in the growth direction of the hexagonal network surface can be obtained by an X-ray diffraction method. The measurement method is a concentration method, and the Gakushin method is preferably used as an analysis method. The crystallite size in the growth direction of the hexagonal mesh plane can be obtained using diffraction lines from the (110) plane.

  Further, as another parameter indicating the degree of graphitization, there is a graphite crystal layer spacing, and the smaller the layer spacing, the higher the crystallinity. The interlayer spacing of the graphite crystals is preferably at least 0.3420 nm or less, more preferably 0.3395 nm or less, and further preferably 0.3370 nm or less, for example, as a calculated value based on the X-ray diffraction line of d002. preferable.

  The graphene sheet end face structure varies greatly depending on whether pulverization is performed before graphitization or pulverization is performed after graphitization. That is, when a pulverization process is performed after graphitization, the graphene sheet grown by graphitization is cut and broken, and the graphene sheet end face tends to be open. On the other hand, when the pulverization treatment is performed before graphitization, the graphene sheet end face is curved in a U-shape during the graphite growth process, and the curved portion is likely to be exposed at the pitch-based graphitized short fiber end. For this reason, in order to obtain a pitch-based graphitized short fiber having a graphene sheet end face closing rate exceeding 80%, it is preferable to perform graphitization after pulverization.

  The pitch-based graphitized short fibers used in the present invention preferably have a substantially flat side observation surface with a scanning electron microscope. Here, “substantially flat” means that the pitch-based graphitized short fibers do not have severe unevenness like a fibril structure. When defects such as severe irregularities are present on the surface of the pitch-based graphitized short fibers, the viscosity increases with the increase of the surface area when kneading with the matrix, and the moldability is deteriorated. Therefore, it is desirable that defects such as surface irregularities be as small as possible. More specifically, it is assumed that there are 10 or less defects such as irregularities in the observation visual field in an image observed at 1000 times with a scanning electron microscope. As a method for obtaining such pitch-based graphitized short fibers, a graphitization treatment can be preferably performed after a pulverization treatment.

  In addition to the thermally conductive filler, the thermally conductive resin composition further includes glass fiber, potassium titanate whisker, zinc oxide whisker, boron in order to further improve moldability, mechanical properties, flame retardancy, and other properties. Fibrous filler such as aluminum fluoride whisker, boron nitride whisker, aramid fiber, alumina fiber, silicon carbide fiber, asbestos fiber, gypsum fiber, metal fiber, and wollastonite, zeolite, sericite, kaolin, mica, clay, pyrophyll Silicates such as light, bentonite, asbestos, talc, alumina silicate, carbonates such as calcium carbonate, magnesium carbonate, and dolomite, sulfates such as calcium sulfate and barium sulfate, glass beads, glass flakes and ceramic beads, aluminum hydroxide, Magnesium hydroxide, etc. Non-fibrous fillers also may be added as necessary. These may be hollow, and two or more of these may be used in combination. However, many of the above compounds have a density higher than that of pitch-based graphitized short fibers, and when the purpose is to reduce the weight, it is necessary to pay attention to the addition amount and addition ratio.

  Examples of the resin used as the matrix include polyesters and copolymers thereof (polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate), polystyrenes (polystyrene, syndiotactic polystyrene, etc.) and copolymers thereof (styrene). -Acrylonitrile copolymers, ABS resins, AES resins, etc.), polymethyl methacrylates and copolymers thereof (especially those containing structures consisting of cyclo rings and derivatives thereof), polylactic acid resins and copolymers thereof, polyacrylonitriles And copolymers thereof, cyclic polyolefins and copolymers thereof (particularly resins containing a cyclo ring, such as JSR brand name “Arton”, Mitsui Chemicals brand name “Apel”, Nippon Zeon registered trademark “Zeonex”, etc.) , Polymethyl Nenes and their copolymers (for example, Mitsui Chemicals registered trademark “TPX”), polyphenylene ethers (PPE) and their copolymers (including modified PPE resins), aliphatic polyamides and their copolymers, Polyimides and copolymers thereof, polyamideimides and copolymers thereof, polycarbonates and copolymers thereof, polyphenylene sulfides and copolymers thereof, polysulfones and copolymers thereof, polyether sulfones and copolymers thereof Polymers, polyether nitriles and copolymers thereof, polyether ketones and copolymers thereof, polyether ether ketones and copolymers thereof, polyketones and copolymers thereof, elastomers, liquid crystalline polyesters, etc. Examples thereof include liquid crystalline polymers. One of these may be used alone, or two or more may be used in appropriate combination.

  In addition, additives that improve the emissivity (infrared emissivity) and various colorants, flame retardants, ultraviolet absorbers, infrared absorbers, antioxidants, and other additives are added to the heat conductive resin composition as necessary. You may do it.

  When the heat conductive resin layer is injection-molded using the heat conductive resin composition containing the above-mentioned heat conductive carbon fibers (particularly pitch-based graphitized short fibers), the gate portion in the resin injection mold is radiated. It is preferable to dispose in the vicinity of a heating element (such as a heating device) that is the target of the above. That is, since the orientation direction of the heat conductive carbon fiber coincides with the flow direction of the heat conductive resin composition, by providing a gate in the vicinity of the heating element, the heat dissipation direction of the heating element and the orientation direction of the heat conductive carbon fiber (thermal conduction) The direction in which the thermal conductivity of the resin is maximized) can be substantially matched, and more efficient heat dissipation may be possible.

[Application of heat dissipation structure]
As specific uses of the heat dissipation structure of the present invention, examples of application to LED lighting tools are illustrated in FIGS. In addition, the use of the heat dissipation structure can be applied to LED lighting fixtures having systems and structures other than those exemplified above, and is not limited to LED lighting fixtures. It can be widely applied to necessary equipment and instruments.

  The LED mounting substrate on which the LED element is mounted is bonded and fixed to a part of the heat dissipation structure through a heat conductive adhesive layer or a heat dissipation sheet, and heat transfer from the LED element to the heat dissipation structure is performed on this contact surface. In addition, the heat is transferred from the LED element to the heat dissipation structure through the device components such as the internal air layer or the electrical insulation layer of the heat dissipation structure, and then the heat moves through the heat dissipation structure. The heat is radiated from the outermost layer of the heat dissipation structure to the external air. Further, in the LED lighting device having the power supply unit therein, not only the LED element but also the power supply unit becomes a heating element, and is radiated to the external air via the heat dissipation structure. In the present invention, heat transfer from the LED element directly to the heat dissipation structure and heat transfer from the LED element to the heat dissipation structure after passing through the internal air layer or equipment component of the heat dissipation structure are efficient. It is characteristic to carry out automatically.

  On the other hand, the overall dimensions and shape of LED lighting fixtures are naturally limited according to the requirements of each application, so heat dissipation structures are required to be as small and compact as possible and as light as possible. If the surface area of the outermost layer of the body is too small for the calorific value of the LED element, even if the heat transfer capability (heat transport capability) of the heat dissipation structure alone is sufficiently high, it is between the outermost layer and the external air. A large amount of heat transfer loss (temperature difference) occurs, the poor heat transfer efficiency becomes the rate-determining factor, the heat generated by the LED element is accumulated in the heat dissipation structure, and the temperature of the entire heat dissipation structure increases. Become. That is, care must be taken because sufficient heat dissipation of the LED element is not performed.

Examples are shown below, but the present invention is not limited thereto.
In addition, each value in a present Example was calculated | required according to the following method.
(1) The average fiber diameter of pitch-based graphitized short fibers was measured from 60 averages using a scale under an optical microscope in accordance with JIS R7607 and obtained from the average value.
(2) The average fiber length of the pitch-based graphitized short fibers was measured from 1500 using a particle size / shape measuring instrument (PITA-1 manufactured by Seishin Enterprise Co., Ltd.) and obtained from the average value.
(3) The crystallite size in the growth direction of the pitch-based graphitized short fibers was determined by the Gakushin method by measuring reflection from the (110) plane appearing in X-ray diffraction.
(4) The end faces of the pitch-based graphitized short fibers were observed with a transmission electron microscope at a magnification of 1,000,000 times and magnified on a photograph at 4 million times to confirm a graphene sheet.
(5) The surface of the pitch-based graphitized short fibers was observed with a scanning electron microscope at a magnification of 1000 times, and irregularities were confirmed.
(6) The thermal conductivity of the thermally conductive resin composition was obtained by cutting out a sample in a 3 mm × 10 mm strip shape from a molded body of a thermally conductive composition having a thickness of 4 mm, and arranging them side by side to integrate them. Was used to determine the thermal conductivity in the in-plane direction.

[Reference Example 1] Production of mesophase-based pitch graphitized short fibers Pitch composed of a condensed polycyclic hydrocarbon compound was used as a main raw material. The optical anisotropy ratio was 100%, and the softening point was 283 ° C. Using a base having a hole with a diameter of 0.2 mm, heated air is ejected from the slits on both sides of the hole at a linear velocity of 5500 m / min to pull the melt pitch, and a pitch short fiber having an average diameter of 11.1 μm. Was made. The spinning temperature at this time was 328 ° C., and the melt viscosity was 13.5 Pa · s. The spun fibers were collected on a belt to form a mat, and then a pitch-based carbon fiber precursor web made of a pitch-based carbon fiber precursor having a basis weight of 350 g / m ^{2 by} cross wrapping.

This pitch-based carbon fiber precursor web was heated from 170 ° C. to 300 ° C. in air at an average heating rate of 5 ° C./min to be infusibilized, and further fired at 800 ° C. This pitch-based carbon fiber web was pulverized with a uniaxial rotary pulverizer and graphitized at 3000 ° C.
The average fiber diameter of the obtained pitch-based graphitized short fibers was 8.2 μm. The crystallite size derived from the thickness direction of the hexagonal mesh surface was 70 nm, and the average fiber length was 140 μm. Further, it was confirmed that the graphene sheet was closed on the end face of the pitch-based graphitized short fiber by observation with a transmission microscope. Further, the surface was substantially flat with one unevenness as observed by a scanning electron microscope.

[Reference Example 2] Thermally conductive resin composition 50 parts by volume of the pitch-based graphitized short fibers obtained in Reference Example 1, and 100 parts by volume of polycarbonate resin (Panlite (registered trademark) L-1250WP manufactured by Teijin Chemicals Ltd.) The mixture was melt-kneaded using a shaft kneader to obtain thermally conductive resin pellets. Using this pellet, a heat conductive molded article having a thickness of 4 mm was obtained using an injection molding machine (EC40NII manufactured by Toshiba Machine). The thermal conductivity of the thermally conductive molded product was 15.3 W / (m · K).

[Example 1]
Injection molding is performed using the heat conductive resin composition of Reference Example 2 (thermal conductivity 15.3 W / m · K), and the heat conductive layer (symbol 1) and the three-dimensional shape shaping layer shown in FIG. A heat dissipation structure in which the endothelium layer (symbol 2) was integrally formed as a continuous layer was produced. The overall shape is a cylindrical shape, and has uneven stripes parallel to the cylinder axis. The outer diameter (symbol 26 in FIG. 18) of the heat dissipation structure of FIG. 15 is 50 mm, the length (symbol 24 in FIG. 18) is 50 mm, the protrusion length (symbol 25 in FIG. 18) is 5 mm, and the protrusion width ( The symbol 23) in FIG. 18 is 2 mm.
The average thickness of the combined inner layer of the base layer and the heat conductive layer is 3 mm, and the product of the heat conductivity and the average thickness is 0.046 W / K. The endothelial layer including the three-dimensional shape shaping layer is directly formed on the inner surface side of the heat conductive layer, and has regular uneven portions schematically illustrated in FIG. Regarding the specifications of the concavo-convex portion (the description of each position is shown in FIG. 2), the average valley width (symbol 9) is 3 mm, the average peak width (symbol 8) is 1 mm, and the average height is the average valley width (symbol 7). The surface area of the region where the three-dimensional shape shaping layer was formed was about 5 times that of the flat surface.

Next, an LED illuminator incorporating this heat dissipation structure as a heat dissipation component of the LED element was produced. That is, in the manner illustrated in FIG. 4, four LED element NS9L153MT-H3 (rated output about 3 W) manufactured by Nichia Corporation is used as the LED element (symbol 14), and the input power is 2.0 W / Elements (4 elements in total, 8 W) were used. As the LED mounting substrate (symbol 13), an AL base substrate having a thickness of about 1 mm and a diameter of 45 mm was used.
The AL base substrate on which the LED element is mounted has the heat dissipation structure via a commercially available heat conductive sealant (symbol 10, Shin-Etsu Chemical Co., Ltd., condensation type RTV silicone rubber KE-3466, heat conductivity 1.9 W / m · K). Fixed to the body. The average thickness of the adhesive layer was about 50 μm.
The light transmissive cover (symbol 15) was prepared by blow molding of an acrylic resin, and a JIS standard E26 base was used as the base. In addition, the inside of the heat dissipation structure of the LED lighting device is an air layer.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode part temperature of the LED element 60 minutes after power-on was about 74 ° C.

[Example 2]
The heat dissipation was the same as in Example 1 except that the combination of the endothelial layer and the heat conductive layer was produced by die casting of an aluminum alloy (ADC12, thermal conductivity of about 96 W / m · K, specific gravity of about 2.7). A structure was produced. The product of thermal conductivity and average thickness was 0.29 W / K. Moreover, the LED lighting fixture was produced by the method similar to Example 1 except the heat dissipation structure.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode temperature of the LED element 60 minutes after power-on was about 69 ° C.

[Example 3]
Using the same heat dissipation structure as that manufactured in Example 1, an LED lighting tool was manufactured in the manner shown in FIG. The heat dissipation structure is filled with a commercially available heat conduction sealant (symbol 19, Shin-Etsu Chemical Co., Ltd., condensation type RTV silicone rubber KE-3466, heat conductivity 1.9 W / m · K), otherwise An LED lighting tool was produced in the same manner as in Example 1.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode part temperature of the LED element 60 minutes after power-on was about 66 ° C.

[Example 4]
A heat dissipation structure shown in FIG. 1 was produced. The heat dissipation layer was injection molded using the heat conductive resin composition of Reference Example 2 (thermal conductivity 15.3 W / m · K), and the endothelial layer was an aluminum alloy (ADC12, thermal conductivity about 96 W / m · K). K, specific gravity of about 2.7) and die cast molding, both of which are heat conductive sealant (symbol 10, Shin-Etsu Chemical Co., Ltd., condensation type RTV silicone rubber KE-3466, thermal conductivity 1.9 W / m · K ) Was bonded and integrated to produce a heat dissipation structure. 1 has an outer diameter (symbol 26 in FIG. 18) of 50 mm, a length (symbol 24 in FIG. 18) of 50 mm, a protrusion length (symbol 25 in FIG. 18) of 5 mm, and a protrusion width (FIG. 18). The symbol 23) in FIG. 2 is 2 mm, and the average thickness of the heat conductive layer is 2 mm. The endothelium layer including the three-dimensional shape shaping layer has regular uneven portions schematically illustrated in FIG. 6, and the thickness of the base layer is 1 mm. Regarding the specifications of the concavo-convex portions (the description of each position is shown in FIG. 2), the average valley width (symbol 9) is 3 mm, the average peak width (symbol 8) is 1 mm, and the average height (symbol 7) is 3. The surface area of the region where the three-dimensional shape shaping layer was formed was about 5 times that of the flat surface. In addition, the product of the synthetic thermal conductivity and the average thickness of the heat dissipation structure in this example is 0.13 W / K. Moreover, the LED lighting fixture was produced by the method similar to Example 1 except the heat dissipation structure.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode temperature of the LED element 60 minutes after power-on was about 71 ° C.

[Example 5]
A heat dissipation structure shown in FIG. 1 was produced. The heat dissipation layer was injection molded using the heat conductive resin composition of Reference Example 2 (thermal conductivity 15.3 W / m · K), and the endothelial layer was an insulating resin (polycarbonate resin (“Panlite” manufactured by Teijin Chemicals). (Registered trademark) LN3010RZ, thermal conductivity of about 0.2 W / m · K), both of which are manufactured by injection molding, and both of them are heat conductive sealant (symbol 10, Shin-Etsu Chemical Co., Ltd., condensation type RTV silicone rubber KE- 3466 and a heat conductivity of 1.9 W / m · K) were bonded and integrated to produce a heat dissipating structure, the outer diameter of the heat dissipating structure of FIG. 18 is 50 mm, the protruding part length (symbol 25 in FIG. 18) is 5 mm, the protruding part width (symbol 23 in FIG. 18) is 2 mm, and the average thickness of the heat conductive layer is 2 mm. Including layers The inner skin layer has a regular uneven portion schematically shown in Fig. 6. The thickness of the base layer is 1 mm About the specifications of the uneven portion (the description of each position is shown in Fig. 2) The average valley width (symbol 9) is 3 mm, the average peak width (symbol 8) is 1 mm, and the average height (symbol 7) is 10 mm, which is 3.3 times the average valley width, and a three-dimensional shape shaping layer is formed. The surface area of the region was about 5 times that of the flat surface, and the product of the combined thermal conductivity and the average thickness of the heat dissipation structure in this example is 0.031 W / K. Except for the body, LED lighting fixtures were produced in the same manner as in Example 1.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode part temperature of the LED element 60 minutes after power-on was about 85 ° C.

[Example 6]
The specifications of the concavo-convex portion (the description of each position is shown in FIG. 2) is as follows: average valley width (symbol 9) 1 mm, average peak width (symbol 8) about 1 mm, average height (symbol 7) is one time the average valley width A heat radiating structure similar to that of Example 1 was manufactured except that the surface area of the region where the three-dimensional shape shaping layer was formed was about twice that of the flat surface. Moreover, the LED lighting fixture was produced by the method similar to Example 1 except the heat dissipation structure.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode part temperature of the LED element 60 minutes after power-on was about 85 ° C.

[Comparative Example 1]
The heat dissipating structure shown in FIG. 15 has the same shape as in Example 1 except that the endothelium layer is not provided with a three-dimensional shape shaping layer, and LED lighting is performed in the same manner as in Example 1 except for the heat dissipating structure. A tool was prepared.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode temperature of the LED element 60 minutes after power-on was about 94 ° C.

[Comparative Example 2]
The heat dissipating structure shown in FIG. 15 has the same shape as in Example 3 except that the endothelium layer is not provided with a three-dimensional shape shaping layer, and LED lighting is performed in the same manner as in Example 3 except for the heat dissipating structure. A tool was prepared.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode temperature of the LED element 60 minutes after power-on was about 87 ° C.

[Comparative Example 3]
The heat dissipation structure shown in FIG. 1 has the same shape as that of Example 4 except that the endothelium layer is not provided with a three-dimensional shape shaping layer, and LED illumination is performed in the same manner as in Example 4 except for the heat dissipation structure. A tool was prepared.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode part temperature of the LED element 60 minutes after power-on was about 91 ° C.

[Comparative Example 4]
The heat dissipation structure shown in FIG. 1 has the same shape as that of Example 5 except that the endothelium layer is not provided with a three-dimensional shape shaping layer, and LED illumination is performed in the same manner as in Example 5 except for the heat dissipation structure. A tool was prepared.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode temperature of the LED element 60 minutes after power-on was about 109 ° C.

[Comparative Example 5]
The specifications of the concavo-convex part (the description of each position is shown in FIG. 2) is as follows: the average valley width (symbol 9) is 0.3 mm, the average peak width (symbol 8) is about 0.3 mm, and the average height (symbol 7) is the average valley A heat-dissipating structure similar to that in Example 1 is manufactured except that the width is 0.3 mm, which is one time the width, and the surface area of the region where the three-dimensional shape shaping layer is formed is about twice that of the flat surface. did. Moreover, the LED lighting fixture was produced by the method similar to Example 1 except the heat dissipation structure.
The lighting test of this LED illuminator was performed in a room adjusted to an ambient temperature of 25 ° C., a K-type thermocouple was fixed in the vicinity of the cathode side solder joint of the LED element, and the heat generation state of the LED element was measured. As a result, the cathode temperature of the LED element 60 minutes after power-on was about 94 ° C.

  The heat dissipation structure of the present invention includes a light emitting element (LED element, laser diode, EL element, etc.), active light receiving element (CCD, etc.), central processing unit (CPU), image processing unit (MPU), inverter element (IGBT, FET). Etc.), devices such as motors, heater elements, etc. that generate heat, devices, instruments, etc. can be suitably used.

DESCRIPTION OF SYMBOLS 1 Thermal conductive layer 2 Endothelial layer 3 including a three-dimensional shape shaping layer Convex part 4 Concave part 5 Base layer 6 of endothelium layer Thickness 7 of endothelium layer Height of convex part 8 Width of convex part 9 Width of concave part 10 Thermal conductive adhesive layer (thermal conductive sealant, etc.)
11 Heating element (LED element mounting board, etc.)
12 Top plate 13 LED mounting substrate 14 LED element 15 Light transmissive cover 16 Power supply substrate 17 Electrical insulation case 18 Base (for connecting to power socket)
19 Electrical insulation layer (thermal conductive sealant, etc.)
20 Electrical insulation layer (resin film, resin plate, paint film, etc.)
21 External Concavity and Concavity Layer 22 Thermal Conductive Layer Thickness 23 Protrusion Width 24 Heat Dissipation Structure Length 25 Protrusion Length 26

Claims (9)

  A heat dissipation structure including a heat conductive layer and an endothelial layer provided on the inner side and having a three-dimensional shape shaping layer on the innermost surface side, wherein the heat conductive layer has a heat conductivity in at least one direction within the layer. Is 2 W / m · K or more, the average thickness is 0.2 to 5 mm, and the product of thermal conductivity and average thickness is 0.01 W / K or more. %, There are a plurality of irregularities, the average valley width of the irregularities is 1-20 mm, the average peak width is 0.5-5 mm, the average height is 1-10 times the average valley width, and The surface area of the region provided with the three-dimensional shape shaping layer disposed so as to be in contact with at least a part of the heating element is 1.2 times or more compared to a flat surface without an uneven portion. Heat dissipation structure.   The heat dissipation structure according to claim 1, wherein the thermal conductivity in at least one direction in the inner layer is 2 W / m · K or more.   The heat dissipation structure according to claim 1 or 2, wherein the endothelial layer is made of the same material as the heat conductive layer.   The heat dissipation structure according to claim 3, wherein the endothelial layer and the heat conductive layer are integrally formed.   The heat release according to any one of claims 1 to 4, wherein the endothelial layer comprises a thermally conductive resin composition containing a thermally conductive filler and having a thermal conductivity in at least one direction in the layer of 2 W / m · K or more. Structure.   The heat dissipation structure according to any one of claims 1 to 5, wherein the heat conductive layer is made of a heat conductive resin composition containing a heat conductive filler.   The heat conductive resin composition according to claim 5 or 6, wherein the heat conductive resin composition contains 10 to 200 parts by volume of a heat conductive filler with respect to 100 parts by volume of the matrix resin.   The heat dissipating structure according to any one of claims 5 to 7, wherein pitch-based graphitized short fibers mainly made of mesophase pitch are used as the heat conductive filler.   The LED lighting tool which used the thermal radiation structure in any one of Claims 1-8 for the thermal radiation component of the LED element.