WO2018084272A1 - Heat dissipation sheet provided with fine projection and recess layer on base material surface, and heat dissipation member - Google Patents

Abstract

[Problem] Provided is a heat dissipation sheet that can effectively radiate the temperature of a heating element to outside. [Solution] Provided are: a thermal conductor that diffuses the heat of the heating element over the entire surface area; and a base material provided on the surface side of the thermal conductor, for which a fine projection and recess layer is formed on the surface, and a projecting part of the fine projection and recess layer has a height of less than 1 µm, and a density of 100 units/1 µm² or greater. More preferably, the projecting part of the fine projection and recess layer has a height of 200 nm or less, and a density of 400 units/1 µm² or greater. In the projecting part of the heat dissipation sheet, the size of the surface area on the side surface of the projecting part is 10 times or greater than the size of the bottom area of the projecting part. The fine projection and recess layer in the heat dissipation sheet is a coating film formed on the base material of the heat dissipation sheet, using any of: a solution of an alkali metal salt silicate compound, a solution of an ultrafine particle silicon dioxide compound, or a solution prepared by mixing alcohols, an organic compound, an inorganic compound, and water with those solutions.

Description

Heat dissipating sheet and heat dissipating member provided with a fine uneven layer on the substrate surface

The present invention relates to a radiation sheet and a heat radiating member that effectively radiate heat from a heating element to the outside.

In recent years, electronic parts such as integrated circuits (ICs) used in electronic devices have increased in heat generation due to increased power consumption due to improvement in the degree of integration and speeding up of operation. Since it is a cause of malfunction of the device and failure of the electronic component itself, countermeasures against heat dissipation are a major problem. In electronic devices, etc., in order to suppress the temperature rise of electronic components (heating elements) during use, an inorganic base material (thermal conductor) with high thermal conductivity is provided on the heating elements, and further, A heat radiating sheet provided with a heat radiation layer (thermal radiator) having a far infrared radiation effect on the surface is used. Such a heat radiating sheet diffuses heat over the entire surface of the heat conductor by the heat conductor, and efficiently radiates the diffused heat from the surface of the heat radiator.

However, at the present time when the density of heat-generating components is rapidly increasing, the heat radiation capacity is not sufficient, so the temperature of the heating element does not drop as expected, and the heat spot has a high temperature corresponding to the shape of the heat-generating part. Will occur. As a result, the malfunction of the electronic device due to the high temperature of the component or the failure of the electronic component itself occurs.
In order to solve such a heat generation problem of electronic components, Patent Document 1 discloses a far-infrared high-intensity for enhancing the cooling effect by far-infrared radiation on a heat conducting aluminum substrate provided in close contact with a heating element. Some have a radiation coating. However, since the surface of the aluminum base material is only formed with a far-infrared radiation coating with a constant thickness, the size of the radiation area is limited, and the heat from the aluminum base material is not radiated sufficiently to the outside. As a result, the temperature of the heating element does not decrease sufficiently, leading to malfunction of the electronic device and failure of the electronic component itself.

Further, Patent Document 2 proposes a structure in which a flexible heat radiation film having an infrared radiation effect is provided on the surface of a graphite film as a heat conductor. However, the contents of Patent Document 2 are those in which a liquid material containing either silicon dioxide or aluminum oxide is applied to the surface of the graphite film and dried to form a heat radiation film. The main purpose is to realize flexibility, and it has not been sufficiently presented that the temperature of the heating element can be effectively radiated to the outside.

Japanese Patent No. 5083578 JP 2008-78380 A

As described above, in Patent Document 1, since the far-infrared radiation coating having a constant thickness is formed on the surface of the aluminum base material that is in close contact with the heating element, the size of the radiation area is limited, and the thermal conductor The heat from the aluminum base material is not sufficiently radiated to the outside, and as a result, the temperature of the heating element does not sufficiently decrease, causing malfunction of the electronic device and failure of the electronic component itself. In Patent Document 2, a heat radiation film is formed by applying and drying a liquid material containing either silicon dioxide or aluminum oxide on the surface of a graphite film to achieve lightness, workability, and flexibility. However, it is not clear whether the temperature of the heating element can be effectively radiated to the outside.

In view of the above situation, an object of the present invention is to provide a heat dissipation sheet that can effectively radiate the temperature of a heating element to the outside.

In order to solve the above-mentioned problems, the heat dissipation sheet of the present invention includes a heat conductor that diffuses heat of the heating element over the entire surface, and a substrate having a fine uneven layer on the surface side of the heat conductor. Is a layer made of an inorganic compound containing silicon dioxide, and the surface area of the fine uneven layer is at least 10 times the surface area of the flat substrate when the fine uneven layer is not provided. It is characterized by.
As a result, the heat transfer coefficient between the heat-dissipating sheet and the air is remarkably increased, that is, the thermal resistance is remarkably reduced, so that the heat energy of the heating element can be effectively radiated to the outside. As a result, the temperature of the heating element can be greatly reduced.
A heat conductor that diffuses heat of the heating element over the entire surface, and a base material that is provided on the surface side of the heat conductor and on which the fine uneven layer is formed. Is less than 1 μm and the density is 100 / μm ² or more. More preferably, the protrusions of the fine uneven layer have a height of 200 nm or less and a density of 400 pieces / 1 μm ² or more.
Here, the base material is preferably a metal or a carbon-based inorganic material. This is because the heat conductivity is high and the heat of the heating element can be instantaneously diffused over the entire surface of the heat conductor.

In the convex portion of the heat dissipation sheet of the present invention, the size of the surface area of the side surface of the convex portion is 10 times or more the size of the bottom area of the convex portion. More preferably, the size of the surface area of the side surface of the convex portion is 14 times or more the size of the bottom area of the convex portion, and more preferably, the size of the surface area of the side surface of the convex portion is the bottom area of the convex portion. Is at least 14.88 times the size of.

The fine uneven layer in the heat dissipation sheet of the present invention is a coating film formed on a substrate using any one of the following 1) to 3). The fine uneven layer has functions of antistatic property, antifouling property, and transmittance improving property.
1) Solution of alkali metal silicate compound 2) Solution of ultrafine silicon dioxide compound 3) Mixing alcohol, organic compound, inorganic compound and water to any of the above solutions 1) or 2) Prepared solution

The present invention. A heat dissipating member comprising a base material bonded and adhered to at least one surface of the heating element, wherein the base material has a fine uneven layer formed on at least one surface other than the surface to be bonded to the heat generating element. It is a layer made of an inorganic compound containing silicon dioxide, and the size of the surface area of the fine uneven layer is at least 10 times the area of the surface side of the flat substrate when the fine uneven layer is not provided. Features.
As a result, the heat transfer coefficient between the heat-dissipating sheet and the air is remarkably increased, that is, the thermal resistance is remarkably reduced, so that the heat energy of the heating element can be effectively radiated to the outside. As a result, the temperature of the heating element can be greatly reduced.

In the heat radiating member of the present invention, the convex portions of the fine uneven layer preferably have a height of less than 1 μm and a density of 100 / μm ² or more.

The heat dissipation member of the present invention is a heat dissipation member comprising a base material that covers a heating element, and the base material has a fine uneven layer formed on at least one surface, and the convex portions of the fine uneven layer have a height. The density is less than 1 μm and the density is 100 / μm ² or more.

In the heat dissipation member of the present invention, more preferably, the protrusions of the fine uneven layer have a height of 200 nm or less and a density of 400 / μm ² or more. Moreover, in the convex part of the heat radiating member of this invention, the magnitude | size of the surface area of the side surface of a convex part is 10 times or more of the magnitude | size of the bottom area of a convex part. More preferably, the size of the surface area of the side surface of the convex portion is 14 times or more the size of the bottom area of the convex portion, and more preferably, the size of the surface area of the side surface of the convex portion is the bottom area of the convex portion. Is at least 14.88 times the size of.

The fine uneven layer in the heat radiating member of the present invention is a coating film formed on a substrate using any one of the following 1) to 3).
1) Solution of alkali metal silicate compound 2) Solution of ultrafine silicon dioxide compound 3) Mixing alcohol, organic compound, inorganic compound and water to any of the above solutions 1) or 2) Prepared solution

The manufacturing method of the heat radiating sheet of the present invention includes the following steps.
1) A base material is provided on the surface side of the heat conductor that diffuses the heat of the heating element over the entire surface. 2) A liquid solution of an inorganic compound containing silicon dioxide is applied to the surface of the base material and dried. Forming a fine uneven layer having a surface area of 10 times or more as compared with the surface side area of

The method for producing heat dissipation according to the present invention is a method for producing a heat dissipating member composed of a base material bonded and adhered on at least one surface of the heating element, and is at least one other than the surface to be bonded to the heating element. One surface is provided with a step of applying a liquid agent of an inorganic compound containing silicon dioxide and drying to form a fine uneven layer having a surface area of 10 times or more as compared to the area on the surface side of the substrate.

The heat-dissipating sheet of the present invention has an effect that a fine uneven layer is formed on the surface of the heat radiator to effectively radiate heat from the heat generator to the outside.

Sectional drawing of the heat-radiation sheet of Example 1 Observation image of the surface of the fine uneven layer of the heat dissipation sheet of Example 1 Dimensional diagram of a model in which the components of the fine uneven layer of the heat dissipation sheet of Example 1 are quadrangular pyramids Dimensional drawing of a model in which the constituent elements of the fine uneven layer of the heat dissipation sheet of Example 1 are conical (A) The image which shows a mode that the fine uneven layer of the thermal radiation sheet of Example 1 was formed on the heat radiation tape, (B) The mode that the fine uneven layer of the thermal radiation sheet of Example 1 was formed on the acrylic resin The image to show, (C) Confirmation image of the antifouling property of the fine uneven layer of the heat-radiation sheet of Example 1, (D) Confirmation image of the light transmittance of the fine uneven layer of the heat-release sheet of Example 1. Sectional drawing of the heat-radiation sheet of Example 2 Sectional drawing of the heat sink of the thermal radiation sheet of Example 2 Sectional drawing of the radiator which applied the heat-radiation sheet of Example 2 Sectional drawing of the solar cell module which applied the heat-radiation sheet of Example 2 Sectional drawing (1) of straight tube | pipe type LED lamp which applied the heat-radiation sheet of Example 3 Sectional drawing (2) of the straight tube | pipe type LED lamp which applied the heat-radiation sheet of Example 3 Sectional drawing (3) of the straight tube | pipe type LED lamp which applied the heat-radiation sheet of Example 3 Sectional drawing of straight tube | pipe type LED lamp which applied the heat-radiation sheet of Example 3 External view of LED spotlight applying heat dissipation sheet of Example 3

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The scope of the present invention is not limited to the following examples and illustrated examples, and many changes and modifications can be made.

FIG. 1 shows a cross-sectional view of one embodiment of a heat dissipation sheet of the present invention. As shown in the cross-sectional view of FIG. 1, the heat radiating sheet 1 includes a fine uneven layer 2, a heat radiator 3, an adhesive layer (A) 4, a heat conductor 5, and an adhesive layer (B) 6. The heat-dissipating sheet 1 is affixed to a pressure-sensitive adhesive layer (B) 6 provided on the bottom surface side of the heat conductor 5 with a heating element (not shown) such as an electronic component serving as a heat source, or in close contact with the heating element. Used. The heat conductor 5 is used for diffusing the heat from the heating element over the entire surface of the heat conductor 5.
An adhesive layer (A) 4 is provided on the surface side of the thermally diffused thermal conductor 5. The heat conductor 5 is bonded to the heat radiator 3 for efficiently radiating heat into the air via the adhesive layer (A) 4. Alternatively, the heat conductor 5 is brought into close contact with the heat radiator 3. On the surface side of the thermal radiator 3, a fine uneven layer 2 is provided for enlarging the radiation area in order to further increase the thermal radiation efficiency. The fine uneven layer 2 having a fine protrusion shape is provided on the surface side of the heat radiator 3 to increase the heat transfer coefficient between the heat radiator 3 and the air and to effectively radiate heat.

The heat conductor 5 is generally made of a metal or carbon-based inorganic material having a high thermal conductivity. In particular, when graphite or graphene, which is one of carbon-based materials, is used, the thermal conductivity is high, and since the heat of the heating element can be instantaneously diffused over the entire surface of the thermal conductor 5, it is suitable as a material for the thermal conductor 5. It is. Considering the material cost, an organic material may be used, but care must be taken because the thermal conductivity is low.
In general, the thermal radiator 3 is often a PET (Polyethylene terephthalate) film, which is advantageous in terms of cost, but the thermal radiation rate is as low as 0.5 to 0.7 in the far infrared region, so that the thermal radiation efficiency is increased. Therefore, a black body sheet or a high heat radiation sheet having a thermal emissivity of 0.9 or more may be used.

The effect of the fine uneven layer 2 that forms the fine protrusion shape on the surface side of the thermal radiator 3 can be explained using Newton's cooling law. That is, heat transfer between objects (substances) is caused by heat transfer on the contact surface, and the amount of heat transfer is proportional to the size of the contact area. That is, the greater the contact area between the two materials, the greater the heat transfer. This is the basic concept of Newton's law of cooling.

The amount of heat radiated into the air from the heat radiator 3 shown in FIG. 1 is proportional to the surface area of the heat radiator 3 and the temperature difference between the heat radiator 3 and air. That the following equation between the quantity of heat Q, the time t, the surface area S (the area in contact with air) of the heat radiator 3, the temperature T of the heat radiator 3, the temperature T _m of a air with thermal radiators 3 The relationship of 1 holds. This is Newton's cooling law.
Here, the proportionality constant α is a constant (heat transfer coefficient) determined by the shape of the contact surface of the heat radiator 3, the nature of air, the way air flows, and the like.

(Equation 1)
−dQ / dt = α · S (T−T _m ) (Formula 1)

As described above, by providing the fine uneven layer 2 on the surface of the heat radiator 3 in order to increase the contact area S with the air, the heat of the heat radiator 3 can be efficiently radiated into the air. By this action, the temperature of the heating element can be reduced.

The fine uneven layer 2 having a fine protrusion shape formed into a surface has a liquid agent in which an ultrafine silicon dioxide compound is mixed in an aqueous solution, an inorganic compound mainly composed of silicon dioxide, an organic compound, a liquid agent mixed in alcohol or water. It can be obtained by coating on the surface of an inorganic or organic substrate and drying. As described above, the fine uneven layer is formed by applying a liquid mixture obtained by mixing silicon dioxides to at least one liquid of water, alcohol, an inorganic compound, and an organic compound on the surface of an inorganic substrate or an organic substrate and drying the mixture. To get. Drying may be natural drying or forced drying in a thermostatic bath. In the case of forcibly drying, the fine uneven layer 2 can be formed on the surface of the inorganic base material or the organic base material in a short time, so that work efficiency can be improved.

FIG. 2 is an image obtained by observing the surface of the fine uneven layer 2 with a scanning probe microscope after a liquid agent in which an ultrafine silicon dioxide compound is mixed in an aqueous solution is applied to a glass substrate and dried. The fine protrusion group constituting the fine uneven layer 2 has approximately 400 or more protrusions in 1 μm ² , and the area occupied by one protrusion is 2.5 nm ² or less on average. The height from the bottom surface of the fine protrusion group is 200 nm or less, and the height of the protrusion group is estimated to be 15 to 30 nm.
The fine uneven layer 2 is a fine solid composed of silicon as a main component. The thermal emissivity of silicon, which is a fine solid, is as large as about 0.9 in the far-infrared region, and the heat of the thermal conductor 5 transmitted to the thermal radiator 3 can be efficiently radiated into the air. Also, the heat conductivity is less than 1 for PET film, silicon is as high as 148, and from the viewpoint of heat conduction, the heat of the heating element can be efficiently radiated into the air, so that the heating element as a heat source It is possible to efficiently reduce the temperature of.
Next, the surface area of the fine uneven layer 2 formed on the surface of the thermal radiator 3 is obtained. It is assumed that the shape of the fine protrusion group of the fine uneven layer 2 is composed of two types of shapes, a quadrangular pyramid and a cone. Since it is these side surfaces that come into contact with air, the side surface area for each is obtained.
Here, since the height of the fine protrusion group is estimated to be 15 to 30 nm, the calculation obtains the area of the side surface (side surface area) at these two values, and is several times the area of the bottom surface (bottom surface area). Calculate how big it will be.

(When the projection is a square pyramid and has a height x)
FIG. 3 is a model diagram in which the area occupied by one fine protrusion is 2.5 nm ² and the shape of the fine protrusion is a quadrangular pyramid, and the side surface area at this time is obtained. In the case of a quadrangular pyramid, if the bottom area occupied by one fine protrusion is 2.5 nm ² , the length of one side is 1.58 nm.
(1) When the height x is 15 nm. Side surface area: 1.58 × 15 ÷ 2 × 4 = 47.4 nm ²
-Bottom area: 1.58 x 1.58 = 2.5nm ²
Accordingly, when the bottom surface is flat, the side surface area of the fine uneven layer 2 is 18.96 times larger than the bottom surface area.
(2) When the height x is 30 nm. Side surface area: 1.58 × 30 ÷ 2 × 4 = 94.8 nm ²
-Bottom area: 1.58 x 1.58 = 2.5nm ²
Accordingly, the side surface area of the fine uneven layer is 37.9 times larger than the size of the bottom surface area when the bottom surface is flat.

(When the protrusion shape is a cone and the height is y)
FIG. 4 is a model diagram in which the area occupied by one fine protrusion is 2.5 nm ² and the protrusion shape is a cone, and the side area at this time is obtained. Here, the area occupied by the bottom surface portion was a square having a side length of 1.58 nm. In the case of a cone, if the bottom area occupied by one protrusion is 2.5 nm ² , the diameter at the bottom is 1.58 nm (radius 0.79 nm).
(1) When the height y is 15 nm Here, when the height of the fine protrusion is 15 nm, the length of the bus bar is also set to 15 nm.
Side area: 3.14 (π) x 0.79 x 15 = 37.2 nm ²
Bottom area: 1.58 x 1.58 = 2.5 nm ²
Accordingly, the side surface area of the fine uneven layer is 14.88 times larger than the size of the bottom surface area when the bottom surface is flat.
(2) When the height y is 30 nm Here, when the height of the protrusion is 30 nm, the length of the bus bar is also set to 30 nm.
Side area: 3.14 (π) x 0.79 x 30 = 74.42 nm ²
Bottom area: 1.58 x 1.58 = 2.5 nm ²
Accordingly, when the bottom surface is flat, the side surface area of the fine uneven layer is 29.77 times the size of the bottom surface area.

As described above, by providing the fine uneven layer 2 made of a group of fine protrusions on the surface of the thermal radiator 3, the surface area of the surface of the thermal radiator 3 is 14. It can be seen that the number increases from 88 times to 37.9 times.
This means that the temperature of the heating element tends to decrease due to Newton's cooling law. As described above, the heat radiating sheet 1 shown in FIG. 1 is a heat radiator without the fine uneven layer 2 because the heat from the heating element is efficiently radiated into the air by providing the fine uneven layer 2 made of the fine protrusion group. Compared to the heat radiating sheet of only 3, it is possible to greatly suppress the temperature rise of the heating element.
Here, it is assumed that the structure of the fine protrusion group constituting the fine uneven layer 2 of FIG. 2 is approximately 400 or more protrusions per 1 μm ² , and the area occupied by one protrusion is an average of 2.5 nm ² or less. If the surface area is increased by providing the fine uneven layer 2, the number of protrusions may be 400 or less, and the area occupied by one protrusion is an average of 2.5 nm ^2. The height from the bottom surface of the fine protrusion group may be 200 nm or more.

FIG. 5A shows an inorganic compound mainly composed of silicon dioxide on the surface of a heat radiation tape 50 (product name: TP7623, thermal emissivity: 0.9) manufactured by Big Technos, which has been commercialized as a heat radiator. 1 shows a state in which an Excel Pure (product name) solution made by Chuo Automobile Co., Ltd. mixed in an organic compound, alcohol and water is applied. The thermal radiation tape 50 is blackish. When water is dripped onto the heat radiation tape 50 in a state where no treatment is performed (blank state), the water droplet exhibits a water repellent state as indicated by reference numeral 52. After applying an Excel pure liquid on the surface of the thermal radiation tape 50 and drying it, when water is dropped, the water repellent state is changed and the water droplet is changed to a hydrophilic state 53 as indicated by reference numeral 53.
Although the fine solid layer composed mainly of silicon exhibits hydrophilicity, it can be seen that the fine uneven layer 2 in which the Excel Pure liquid is dried is formed on the surface of the heat radiation tape 50.

FIG. 5 (B) is a micrograph in a state where an Excel pure liquid is applied on an acrylic resin and dried. From FIG. 5 (B), it can be seen that the fine protrusion groups as shown in FIG. 2 are formed on the surface of the heat radiation tape 50. Fine solids composed mainly of silicon exhibit antifouling and antistatic effects due to the hydrophilic action associated with moisture in the air, so they can be used in adverse environments where dust and oil are scattered. Since the dust has a property that the oil does not easily adhere to the heat radiating sheet 1, the highly reliable heat radiating sheet 1 can be obtained.

FIG. 5 (C) shows a case where dust (here, flour is used) is applied to the thermal radiation tape 50 in order to confirm the effect of the fine uneven layer 2 formed by applying and drying an Excel pure liquid on the thermal radiation tape 50. This shows the result of examining the adhesion of flour. (A) is an area where the Excel pure solution is not applied to the left region of the thermal radiation tape 50, and the right region is an area where the Excel pure solution is applied. (B) shows a state where both areas are covered with flour, which is dust. (C) is an observation of how much flour is adhered to the heat radiation tape 50 by tilting the heat radiation tape 50 and forcibly dropping the flour. Flour in the area where the Excel Pure liquid is applied It can be seen that the adhesion amount of is significantly reduced. As a result, due to the hydrophilic action (antifouling effect and antistatic effect) of the fine uneven layer 2 formed with the Excel Pure liquid, the fine uneven layer 2 coated with the Excel Pure liquid has the effect of increasing the heat dissipation. It turns out that there is antifouling action.

FIG. 5 (D) shows that the fine uneven layer 2 formed on the organic base material 55 by applying the Excel Pure liquid thinly on one side with a bar coater on the transparent organic base material 55 has a transmittance improving effect. It is a sample for confirming. The used organic base material 55 is a transparent polycarbonate sheet (manufactured by Idemitsu Kosan Co., Ltd., product name LC1500, thickness 1 mm).
Here, (A) is a blank state in which the Excel Pure liquid is not applied on the organic substrate 55. When water is dropped here, a water repellent state 52 is shown. (B) shows a state in which an Excel pure solution is applied to the organic base material 55 with a bar coater, and water is dropped after drying. When water is dropped, it can be seen that the surface of the organic base material 55 shows a hydrophilic state 53 and the fine uneven layer 2 is formed.

Next, when the transmittance was measured using a luminance meter, the transmittance in the blank state in which the organic pure material 55 was not applied to the organic base material 55 in (A) was 90%, whereas Excel Pure. It turned out that the transmittance | permeability of the organic base material 55 of (b) which apply | coated the liquid agent and formed the fine uneven layer 2 improved to 94%. This is presumed that the fine uneven layer 2 has a reduced reflectance due to the action similar to that of the nano-moth eye structure, as shown in FIGS. 2 and 5B. As described above, it was found that the organic base material 55 provided with the fine uneven layer 2 on the transparent organic base material 55 is improved in light utilization efficiency characteristics as well as in heat radiation characteristics. From this, it is possible to obtain both effects of thermal radiation effect and light extraction effect at the same time by forming the fine uneven layer 2 on a transparent organic base material applied to lighting devices and display devices. I understand that.

FIG. 6 shows a heat dissipation sheet 1a composed of the fine uneven layer 2, the second fine uneven layer 7, the heat radiator 3, the adhesive layer (A) 4, the thermal conductor 5, and the adhesive layer (B) 6. The difference from FIG. 1 is that a second fine uneven layer 7 is provided on the back surface of the thermal radiator 3 on the adhesive layer (A) 4 side. Since the second fine uneven layer 7 has hydrophilicity, the generation of air (fine air bubbles) is suppressed by improving the wettability with the adhesive for forming the adhesive layer. Since the adhesion force is improved and the adhesion area with the adhesive layer (A) 4 is also increased, the heat from the heat conductor 5 can be efficiently transferred to the heat radiator 3.

FIG. 7 shows a heat sink type heat radiating sheet 8 composed of a fine uneven layer 2, a heat sink metal substrate 9 of a heat radiator, an adhesive layer (A) 4, a heat conductor 5, and an adhesive layer (B) 6. A difference from FIG. 1 is that a fine uneven layer 2 is formed on the surface of a heat sink type metal substrate 9 which is mainly used as a heat radiator based on an aluminum substrate. In an environment where the temperature of the heating element further increases, there is a possibility that heat radiation to the outside is not sufficient in the heat sink type metal substrate 9 having a flat surface and the temperature of the heating element does not decrease.
In the heat sink type heat radiating sheet 8 of the present embodiment, since the fine uneven layer 2 is provided on the surface of the heat sink type metal substrate 9, the radiation area increases, and accordingly, the heat radiation from the heat sink type metal substrate 9 increases. As a result, the temperature of the heating element decreases.

FIG. 8 shows a basic part of the radiator 30 used in a heat exchanger such as an automobile, a vehicle, and an air conditioner. In general, in an automobile, hot water sent from an engine by a water pump (not shown) is cooled using the radiation fins 31 and the cooling plate 32, and the cooled water is circulated to cool the engine system. Here, since the heat radiating area is increased by providing the fine uneven layer 2 on the heat radiating fin 31, the heat of the radiating fin 31 is radiated more than before, and as a result, the temperature rise of the engine is suppressed and the mechanical system, electronic / electrical The system can operate stably without failure.

FIG. 9 is a cross-sectional view of the solar cell module. First, a method for manufacturing the solar cell module 40 will be briefly described. After laminating the upper EVA (Ethylene VinylAcetate) sheet 42, the solar battery cell 43, the lower EVA sheet 44, and the light-resistant film 45 in this order based on the heat strengthened white plate glass 41, this laminating apparatus is introduced. 9 is heated while evacuating the inside of the apparatus, the upper EVA sheet 42 and the lower EVA sheet 44 are melted, and the solar cells 43 are firmly bonded to the heat-strengthened white plate glass 41, whereby the configuration shown in FIG. 9 can be produced. .

Next, when the frame 46 and the sealing material 47 are provided, the solar cell module 40 is manufactured. The frame 46 and the sealing material 47 are provided for the purpose of reinforcing mechanical strength and preventing moisture penetration when the solar cell module 40 is used outdoors for a long time. Usually, the frame 46 is an anodized aluminum frame. The sealing material 47 is made of butyl rubber, which has good environmental resistance and electrical characteristics such as heat aging resistance, chemical resistance, and weather resistance, and has particularly low gas permeability. As the light-resistant film 45, a sheet having a structure in which aluminum having high moisture-proof and insulating ability is sandwiched between polyvinyl fluoride films (PVF: Poly-Vinyl Fluoride) is used.

When the solar cell module 40 receives sunlight, it is converted from light to electricity by the solar battery cell 43 and is taken out as electromotive force. Here, when the amount of luminous flux of sunlight is large, the photovoltaic / electrical conversion electromotive force of the solar battery cell 43 is increased, so that the temperature of the solar battery cell 43 is increased. Since the conversion efficiency of the solar battery cell 43 decreases as the temperature rises, the conversion efficiency greatly decreases due to the heat in the solar battery module 40 when the amount of sunlight is large as in the summer of Japan. Heat countermeasures are required.

Here, by providing the fine uneven layer 2 of the present invention on the surface of the heat-strengthened white plate glass 41, the frame 46 and the light-resistant film 45, the heat generated in the solar battery cell 43 is effectively radiated to the outside. The temperature rise of the solar battery cell 43 is suppressed, and the solar battery cell 43 is subjected to photoelectric conversion with high efficiency.
Moreover, since the fine uneven layer 2 is formed on the surface of the solar cell module 40, it becomes difficult for dust and other dirt to adhere thereto. In particular, since the antifouling action is exhibited on the surface of the heat-strengthened white plate glass 41, there are few things that prevent the solar cells 43 from being irradiated with sunlight, and the amount of light / electricity conversion increases accordingly. Moreover, since the fine uneven layer 2 has an effect of improving the transmittance, the amount of light / electric conversion is increased accordingly.

FIG. 10 is a cross-sectional view of the straight tube LED lamp 10. An LED 12 is attached to the electronic board 15, and an electronic circuit group for controlling the brightness of the LED 12 is mounted. The light emitted from the LED 12 illuminates the front space through the transparent substrate 13. The power source 14 is integrated with the electronic substrate 15 and applies a voltage to the electronic substrate 15.
The aluminum base 11 mechanically protects the electronic board 15 and the power supply 14 and radiates heat from the LED 12, the power supply 14 and the electronic circuit group mounted on the electronic board 15 to the outside. The rise of the temperature in the tube of the straight tube LED lamp 10 is suppressed so that the electronic circuit group mounted on 15 operates stably or does not cause a failure.

However, although the aluminum base 11 has a high thermal conductivity of about 250, the thermal emissivity is 0.8 or less even when anodized, and heat from the LED or power source cannot be efficiently radiated to the outside. With the recent increase in luminance and mounting of the straight tube LED lamp 10, the temperature inside the tube of the straight tube LED lamp 10 is further increased, leading to a decrease in the luminous efficiency of the LED 12 and a shortened life.

In the present invention, in order to improve these disadvantages, the fine uneven layer 2 is provided outside the aluminum base 11 to increase the surface area of the aluminum base 11 to radiate heat efficiently, and the fine uneven layer 2. Since the heat emissivity of the fine solid material composed mainly of silicon forming the silicon is as large as about 0.9 in the far-infrared region, the heat in the tube can be effectively radiated to the outside. As a result, an increase in the temperature inside the tube of the straight tube type LED lamp 10 is suppressed, and as a result, a reduction in luminance of the LED 12 is improved, a long life is achieved, and the electronic circuit group mounted on the electronic substrate 15 is stabilized. Operation can be performed, and failure occurrence can be greatly reduced.

FIG. 11 shows a structure in which a third fine uneven layer 16 is provided on the inner surface of the aluminum base 11 of the straight tube LED lamp 10 shown in FIG. The third fine uneven layer 16 has an effect of efficiently transferring heat from the electronic circuit group mounted on the LED 12, the power supply 14, and the electronic substrate 15 to the aluminum base material 11. As a result, an increase in the temperature inside the tube of the straight tube type LED lamp 10 is suppressed, and as a result, a reduction in luminance of the LED 12 is improved, a long life is achieved, and the electronic circuit group mounted on the electronic substrate 15 is stabilized. Operation can be performed, and failure occurrence can be greatly reduced.

In FIG. 12, the fine uneven layer 2 is provided on the surface of the transparent substrate 13. The heat radiation from the electronic circuit group mounted on the LED 12, the power supply 14, and the electronic substrate 15 is provided on the inside of the transparent substrate 13 by providing the fine uneven layer 2, so that the heat in the tube is also released from the transparent substrate 13 to the outside. It can be radiated efficiently. That is, since the transparent substrate 13 is usually made of polycarbonate or acrylic polymer resin having an extremely low thermal conductivity of 0.3 or less, the heat in the tube of the straight tube LED lamp 10 is passed through the transparent substrate 13. Although it is difficult to radiate to the outside, the surface area of the transparent base material 13 is increased by providing the fine uneven layer 2 on the surface of the transparent base material 13, so that it is mounted on the LED 12, the power supply 14 and the electronic substrate 15. More heat can be radiated to the outside of the tube. As a result, the luminance reduction of the LED 12 is improved and the lifetime is extended, and the electronic circuit group mounted on the electronic board 15 is stably operated and the occurrence of failure is reduced.
Further, as described with reference to FIG. 5D, since the transmittance of the transparent substrate 13 is improved when the fine uneven layer 2 is provided on the surface of the transparent substrate 13, the supply from the power source 14 to the LED 12 is increased accordingly. Since the power can be reduced, the temperature rise of the LED 12 and the power source 14 is suppressed, the brightness reduction of the LED 12 due to heat is improved and the life is extended, and the electronic circuit group mounted on the electronic board 15 is stable. It is possible to operate and reduce the occurrence of failures.

FIG. 13 is obtained by providing a fourth fine uneven layer 17 on the inner surface of the transparent substrate 13 of the straight tube LED lamp 10 shown in FIG. 12 and a fifth fine uneven layer 18 on the LED surface. The heat from the electronic circuit group mounted on the LED 12, the power supply 14, and the electronic substrate 15 is provided on the front and back of the transparent substrate 13 by providing the fine uneven layer 2 and the fourth fine uneven layer 17 on the outside. Has the effect of radiating efficiently. Moreover, by providing the 5th micro uneven layer 18 on the surface of LED12, the heat | fever which LED12 generate | occur | produces can also be radiated | emitted efficiently, and it becomes possible to reduce the heat | fever of LED12 itself by this.
The formation of the fine uneven layer 2, the fourth fine uneven layer 17, and the fifth fine uneven layer 18 suppresses an increase in the tube temperature of the straight tube LED lamp 10, and as a result, the brightness reduction of the LED 12 is improved. As a result, the service life of the electronic circuit group mounted on the electronic board 15 can be reduced and the failure can be reduced.
In FIG. 13, the fine uneven layer 2 is provided on the surface of the transparent substrate 13, and the fourth fine uneven layer 17 is provided on the inner surface. However, even if only one surface is provided, the heat in the tube of the straight tube LED lamp 10 is not increased. To reduce.

FIG. 14 is an external view of the LED spotlight 20 and a cross-sectional view of the LED optical lens 21. Inside the cover 24, an electronic circuit group (not shown) for controlling the brightness of the LED 23, a power supply (not shown) for supplying a voltage to the electronic circuit group, and the like are mounted. The light emitted from the LED 23 illuminates the front space through the optical lens 22. The cover 24 is usually made of a metal having high thermal conductivity. As a metal used for the cover 24, an aluminum base material is preferable because of its high thermal conductivity and light weight.
However, the material of the cover 24 is not limited to metal, and an organic base material may be used. The cover 24 protects the mechanical shocks to the electronic circuit group and the power source and prevents a decrease in the reliability of the electrical system due to dust, and also radiates heat from the power source, the electronic circuit group and the LED 23 to the outside. The rise in the temperature in the cover 24 is suppressed so that the group operates stably or does not cause a failure.

Due to the recent increase in brightness and density of the LED spotlight 20, the temperature in the tube of the LED spotlight 20 is further increased, leading to a decrease in luminous efficiency of the LED 23 and a shortened life. In order to remedy these drawbacks, the seventh fine uneven layer 26 is provided outside the cover 24 to increase the surface area of the cover 24 that radiates heat, and the silicon that forms the seventh fine uneven layer 26 is mainly used. Since the thermal emissivity of the fine solid material constituted as a component is as large as about 0.9 in the far infrared region, the heat in the tube of the LED spotlight 20 can be effectively radiated to the outside.
As a result, an increase in the temperature inside the LED spotlight 20 can be suppressed. As a result, the luminance of the LED 23 can be reduced, and the life of the LED 23 can be extended. Is done. Further, when the eighth fine uneven layer 27 and the sixth fine uneven layer 25 are provided on the surface of the LED 23 and the optical lens 22 constituting the LED optical lens 21, the temperature of the LED 23 can be further reduced. Further, as described with reference to FIG. 5D, when the fine uneven layer 27 is provided on the surface of the optical lens 22, the light extraction efficiency is improved and the amount of light flux is improved. By reducing the input power, the temperature rise of the electronic circuit group and the LED 23 can be suppressed. As a result, an increase in the temperature inside the LED spotlight 20 is suppressed, and a decrease in luminance of the LED 23 is improved, and a stable operation of the electronic circuit group and the occurrence of a failure are greatly mitigated.

Further, by providing the sixth fine uneven layer 25 on the surface of the optical lens 22 and the eighth fine uneven layer 27 on the surface of the LED 23, heat from the LED 23, the power source, and the electronic circuit group can be efficiently radiated to the outside. Therefore, the luminance reduction of the LED 23 is improved and the life is extended. Since the sixth fine uneven layer 25, the seventh fine uneven layer 26, and the eighth fine uneven layer 27 are formed as shown in FIG. 5C, adhesion of dust and oils is alleviated. Even in an adverse installation environment, the LED spotlight 20 can be installed.

The present invention is useful for a heat dissipation sheet.

1, 1a Heat dissipation sheet 2 Fine uneven layer 3 Thermal radiator 4 Adhesive layer (A)
5 Thermal conductor 6 Adhesive layer (B)
7 Second fine uneven layer 8 Heat sink type heat dissipation sheet 9 Heat sink type metal base material 10 Straight tube type LED lamp 11 Aluminum base material 12 LED
DESCRIPTION OF SYMBOLS 13 Transparent base material 14 Power supply 15 Electronic substrate 17 4th fine uneven layer 18 5th fine uneven layer 20 LED spotlight 21 LED optical lens 22 Optical lens 23 LED
24 Cover 25 6th fine uneven layer 26 7th fine uneven layer 27 8th fine uneven layer 30 Radiator 31 Radiation fin 32 Cooling water plate 40 Solar cell module 41 Heat strengthened white plate glass 42 EVA sheet 43 Solar cell 44 Lower EVA sheet 45 Light-resistant film 46 Frame 47 Sealing material 50 Thermal radiation tape 51 Coating area of liquid agent 52 Water repellent state 53 Hydrophilic state 55 Organic substrate

Claims (16)

A thermal conductor that diffuses the heat of the heating element throughout the surface;
On the surface side of the heat conductor, a substrate having a fine uneven layer,
The fine uneven layer is a layer made of an inorganic compound containing silicon dioxide,
The size of the surface area of the fine uneven layer is at least 10 times as large as the area on the surface side of the flat substrate when the fine uneven layer is not provided. ^2. The heat dissipation sheet according to claim 1, wherein the convex portions of the fine uneven layer have a height of less than 1 μm and a density of 100 / μm ² or more. 3. The heat dissipation sheet according to claim 1, wherein the convex portions of the fine uneven layer have a height of 200 nm or less and a density of 400 / μm ² or more. The heat radiating sheet according to any one of claims 1 to 3, wherein a surface area of the side surface of the convex portion of the convex portion is 10 times or more a size of a bottom area of the convex portion. The heat radiation sheet according to any one of claims 1 to 3, wherein a surface area of the side surface of the convex portion in the convex portion is 14 times or more a size of a bottom area of the convex portion. The heat dissipation sheet according to any one of claims 1 to 5, wherein the fine uneven layer is a coating film formed on the substrate using any one of the following 1) to 3):
1) a solution of an alkali metal silicate compound,
2) Ultrafine silicon dioxide compound solution,
3) A solution prepared by mixing an alcohol, an organic compound, an inorganic compound, and water with the solution of either 1) or 2) above. The heat dissipation sheet according to claim 6, wherein the fine uneven layer has antistatic properties, antifouling properties, and improved transmittance. A heat dissipating member comprising a base material bonded and adhered on at least one surface of a heating element,
The substrate has a fine uneven layer formed on at least one surface other than the surface to be joined to the heating element,
The fine uneven layer is a layer made of an inorganic compound containing silicon dioxide,
The size of the surface area of the fine uneven layer is at least 10 times as large as the area on the surface side of the flat substrate when the fine uneven layer is not provided. The heat radiating member according to claim 8, wherein the protrusions of the fine uneven layer have a height of less than 1 μm and a density of 100 / μm ² or more. A heat dissipating member comprising a base material covering the heating element,
The substrate has a fine uneven layer formed on at least one surface,
The heat dissipation member, wherein the protrusions of the fine uneven layer have a height of less than 1 μm and a density of 100 / μm ² or more. 11. The heat radiating member according to claim 8, wherein the protrusions of the fine uneven layer have a height of 200 nm or less and a density of 400 / μm ² or more. The heat radiating member according to any one of claims 8 to 11, wherein the surface area of the side surface of the protrusion is 10 times or more the size of the bottom area of the protrusion. The heat radiating member according to any one of claims 8 to 11, wherein in the convex portion, the size of the surface area of the side surface of the convex portion is 14 times or more the size of the bottom area of the convex portion. The heat radiating member according to any one of claims 8 to 13, wherein the fine uneven layer is a coating film formed on the substrate using any one of the following 1) to 3):
1) a solution of an alkali metal silicate compound,
2) Ultrafine silicon dioxide compound solution,
3) A solution prepared by mixing an alcohol, an organic compound, an inorganic compound, and water with the solution of either 1) or 2) above. Providing a substrate on the surface side of the heat conductor that diffuses the heat of the heating element throughout the surface;
Applying a liquid agent of an inorganic compound containing silicon dioxide on the surface of the substrate and drying to form a fine uneven layer having a surface area of 10 times or more compared to the area of the surface side of the substrate; A method for producing a heat dissipation sheet, comprising: A method for producing a heat dissipation member comprising a base material bonded and adhered on at least one surface of a heating element,
The substrate is coated with an inorganic compound solution containing silicon dioxide on at least one surface other than the surface to be bonded to the heating element and dried, and is 10 times the area on the surface side of the substrate. Forming a fine uneven layer having the surface area as described above.

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