JP2006250513A - Far infrared radiation cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a far infrared radiation cooling device having higher radiation cooling performance than conventional one. <P>SOLUTION: The far infrared radiation cooling device 10 comprises a far infrared radiation layer 16 formed of a fine crystal grain aggregate of a far infrared radiation material and provided on the surface of a heat transfer member 14. Thus, heat conducted from a semiconductor 12 is radiated as radiation energy from the far infrared radiation layer 16. The far infrared radiation layer 16 develops high radiation cooling performance without the need for a binder or a base material formed of a material having low far infrared radiation capability. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a far-infrared radiation cooling device for cooling a heat transfer member by radiating electromagnetic waves from a far-infrared radiation layer fixed to the surface of the heat transfer member.

For cooling the heat transfer member by radiating electromagnetic waves from the far-infrared radiation layer fixed to the surface of the heat transfer member as a way to achieve maximum cooling at a low cost in a limited space Far-infrared radiant cooling devices are known. For example, this is the heat dissipating material for electronic components described in Patent Document 1. According to this, substances emitting far infrared rays, such as alumina, zirconia, titania, cordierite, β-spodumene, aluminum titanate, fiber element oxide ceramics, silicon resin, glass, porous ceramics, etc. It is configured by being mixed in a solid or porous substrate.
Japanese Patent Application Laid-Open No. 7-161884

  By the way, in the said conventional heat dissipation material for electronic components, since the binder with low radiation efficiency is generally used in order to couple | bond a far-infrared radiation material, inconvenience that sufficient cooling performance close | similar to a theoretical limit cannot be obtained. there were.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a far-infrared radiation cooling device capable of obtaining a high radiation cooling performance as compared with the conventional one.

  While the inventor has repeatedly studied the radiation cooling performance of the far-infrared radiation layer of the far-infrared radiation cooling apparatus, the conventional far-infrared radiation layer has a far-infrared radiation material mixed into the base material (base material) or It is configured by being bound by an organic binder such as resin or an inorganic binder such as glass, and the base material or the binder itself is a substance having lower far-infrared radiation ability than far-infrared radiation material. Estimating that it is an obstacle to obtaining radiant cooling performance, and constructing a far-infrared radiation layer from a collection of fine crystal grains of far-infrared radiation material without using a substrate or a binder, its far-infrared radiation It has been found that the radiation ability is increased and a suitably high radiation cooling performance can be obtained. The present invention has been made based on such findings.

  That is, the gist of the far-infrared radiation cooling device of the invention according to claim 1 for solving the above-described problem is that a far-infrared radiation layer composed of an aggregate of fine crystal grains of a far-infrared radiation material is transmitted through the far-infrared radiation layer. It is provided on the surface of the heat member.

  Further, the gist of the invention according to claim 2 is that the far-infrared radiation material is fixed to the surface of the heat transfer member by spraying the far-infrared radiation material.

  Further, the gist of the invention according to claim 3 is that the far-infrared radiation material absorbs a wavelength greater than or equal to a peak wavelength determined based on an actual temperature from the Wien's displacement law equation. In addition, the electromagnetic wave having a predetermined wavelength corresponding to the far infrared is reflected.

  The gist of the invention according to claim 4 further includes electromagnetic wave absorbing means for absorbing electromagnetic waves radiated from the far-infrared radiation layer fixed to the surface of the heat transfer member by a fluid.

  According to the far-infrared radiation cooling apparatus of the invention according to claim 1, since the far-infrared radiation layer composed of the aggregate of the fine crystal grains of the far-infrared radiation material is provided on the surface of the heat transfer member, the far-infrared radiation It is not necessary to use a binder or a substrate made of a substance having low radiation ability, and high radiation cooling performance can be obtained.

  According to the far-infrared radiation cooling apparatus of the invention according to claim 2, the far-infrared radiation material is fixed to the surface of the heat transfer member by spraying the far-infrared radiation material. Therefore, since a binder or base material made of a substance having low far-infrared radiation is not used, high radiation cooling performance can be obtained.

  According to the far-infrared radiation cooling apparatus of the invention according to claim 3, the far-infrared radiation material absorbs a wavelength that is equal to or greater than the peak wavelength determined based on the actual temperature from the Wien's displacement law equation. Since it reflects an electromagnetic wave having a predetermined wavelength corresponding to infrared and far infrared, sufficient radiation cooling performance close to the theoretical limit can be obtained.

  According to the far-infrared radiation cooling device of the invention according to claim 4, further comprising an electromagnetic wave absorbing means for absorbing the electromagnetic wave radiated from the far-infrared radiation layer fixed to the surface of the heat transfer member by the fluid. Therefore, higher radiation cooling performance can be obtained.

  Here, preferably, in the heat transfer member, at least the base material is made of a metal having a high thermal conductivity such as silver, a silver alloy, copper, a copper alloy, aluminum, or an aluminum alloy. In this way, the heat of the heat transfer member is suitably transferred to the far infrared radiation layer. The surface of the base material such as a copper alloy may be subjected to surface treatment such as nickel plating or gold plating.

  Preferably, the heat transfer member is directly or indirectly fixed to a semiconductor element that generates heat during operation, and conducts heat generated from the semiconductor element to cool the semiconductor element. Is. In this way, the semiconductor element is efficiently dissipated, performance is maintained, and durability is enhanced. As the semiconductor element, a high-power LED, a high-power LD, a central processing element (CPU) capable of high-speed computation, and the like can be considered.

  Preferably, the fluid used in the electromagnetic wave absorbing means is a gas capable of absorbing far infrared rays such as air, carbon dioxide gas, air containing water vapor, ammonia gas, or far infrared rays such as colored water or oil. Absorbable liquids are used.

Preferably, the far-infrared radiation material comprises (1) (1-a) group 4 (IVA group) to group 7 (VIIA group) or group 14 (VIB group) carbides, (1-b ) Group 4 or 14 borides, (1-c) Group 4, 13 (VB) or 14 nitrides, (1-d) Group 6 (VIA), Group 7 (VIIA Group), Group 8 (Group VIII), Group 9 (Group IB), Group 10 (Group IIB), Group 11 (Group IIIB) oxides, at least one single component, (2) Group 2 Spinel structure (AB ₂ O ₃ ), (3) (Lantanoid group, Group 2) and Group 6, Group 7 obtained by reaction between Group (IIA) and Group 6, Group 7, Group 8, Group 9 Perovskite structure (ABO ₃ ) obtained by the reaction between group 8 and group 9, (4) The main components are SiO ₂ , Al ₂ O ₃ + B ₂ O ₃ , Na ₂ O, K ₂ O, Li ₂ Glass composed of O, (5) A glass composition in which one or more of the single component (1), the spinel structure (2), and the perovskite structure (3) are dispersed in a glass. is there. According to such a far infrared radiation material, high radiation cooling performance can be obtained.

  Preferably, the far-infrared radiation layer is formed by spraying the far-infrared radiation material on the surface of the heat transfer member using a thermal spraying device such as powder-type or rod-type flame spraying, explosion spraying, and plasma spraying. Is done. The surface of the heat transfer member is subjected in advance to surface treatment and heat treatment for improving adhesion. Thus, the far-infrared radiation layer is composed of an aggregate of fine crystal grains of the far-infrared radiation material fixed to each other when fine droplets collide with each other and rapidly cooled. In the flame spraying, for example, spray particles from a far-infrared radiation material in the form of a powder or a rod heated by an oxygen-acetylene flame are collided with the surface of the heat transfer member at a predetermined speed. In the explosive spraying, the far-infrared radiation material particles are collided with the surface of the heat transfer member at high speed by explosion, and are brought into close contact by heating due to the collision. In the plasma spraying, a high-temperature gas (plasma) generated between the discharge electrodes is used as a heat source to cause the sprayed particles from the far-infrared radiation material to collide with the surface of the heat transfer member at a high speed. In any thermal spraying, fine particles of the far-infrared radiation material are fixed to the surface of the heat transfer member without using a binder.

  Hereinafter, a far infrared radiation cooling apparatus 10 according to an embodiment of the present invention will be described with reference to FIG. In FIG. 1, a semiconductor element 12 is an IC chip for a high-speed CPU, a high-power LED chip, a high-power semiconductor laser diode chip, an IGBT for an inverter, a power transistor chip or the like. In order to maintain performance, it is necessary to be cooled below a predetermined temperature. The semiconductor element 12 is fixed to one surface of the heat transfer member 14 having high thermal conductivity by bonding with an adhesive, thermocompression bonding by heat pressing, soldering, or the like. In this embodiment, the far infrared radiation layer 16 is fixed, and the heat transfer member 14 functions as the far infrared radiation cooling device 10.

  The heat transfer member 14 is made of, for example, a metal having high thermal conductivity such as oxygen-free copper, and is plated on its surface to enhance rust prevention and solderability as necessary. The heat transfer member 14 functions as a heat reservoir, and a far infrared radiation layer 16 is fixed to the other surface by spraying a far infrared radiation material. In this spraying, for example, by using a high-temperature gas (plasma) generated between the discharge electrodes as a heat source, fine droplets of the far-infrared radiation material are generated, and the sprayed particles as the droplets have a relatively high velocity. Then, a plasma spraying device that collides with the surface of the heat transfer member 14 is used.

  The far-infrared radiation layer 16 is composed of an aggregate in which fine particles of the far-infrared radiation material collide with each other, so that fine particles of the far-infrared radiation material are fixed to each other. That is, the far-infrared radiation layer 16 of the present embodiment is composed exclusively of fine particles of the far-infrared radiation material, and the fine particles of the far-infrared radiation material are bonded to each other and fixed to the surface of the heat transfer member 14. It is characterized in that no binder such as glass is used.

The far-infrared radiation material constituting the far-infrared radiation layer 16 includes (1) (1-a) Group 4 (IVA group) to Group 7 (VIIA group) or Group 14 (VIB group) carbides, (1 -b) Group 4 or 14 borides, (1-c) Group 4, 13 (VB) or 14 nitrides, (1-d) Group 6 (VIA), Group 7 (VII) Group 8 (Group VIII), Group 9 (Group IB), Group 10 (IIB Group), Group 11 (Group IIIB) oxides of at least one single component, (2) Spinel structure (AB ₂ O ₃ ) obtained by reaction between Group 2 (Group IIA) and Group 6, Group 7, Group 8, Group 9 (3) (Lantanoid Group 2, Group) and Group 6, Perovskite structure (ABO ₃ ) obtained by reaction between Group 7, Group 8 and Group 9, (4) The main components are SiO ₂ , Al ₂ O ₃ + B ₂ O ₃ , Na ₂ O, K ₂ O, High melting point composed of Li ₂ O Glass, (5) a glass in which one or more of the single component (1), the spinel structure (2), and the perovskite structure (3) are dispersed in the high melting point glass It is composed of a composition.

  The far-infrared radiation material constituting the far-infrared radiation layer 16 absorbs a wavelength equal to or larger than the peak wavelength λm (T) determined based on the actual temperature T from the Wien's displacement law equation (1). It reflects electromagnetic waves having a predetermined wavelength corresponding to infrared and far infrared. FIG. 2 shows an example of the energy distribution radiated from the far-infrared radiation material at each temperature T. The peak wavelength λm (T) of the wavelength distribution at the predetermined temperature T is indicated by the diagonal line in FIG. ) And corresponds to the above equation (1). As shown in FIG. 2, the far-infrared radiation material constituting the far-infrared radiation layer 16 approximates the wavelength distribution of the energy radiated from the black body, so that sufficient radiation cooling performance close to the theoretical limit can be obtained. .

  λm × T = 2898μm ・ K (1)

  According to the far-infrared radiation cooling apparatus 10 of the present embodiment, the far-infrared radiation layer 16 composed of an aggregate of fine crystal grains of far-infrared radiation material is provided on the surface of the heat transfer member 14, so that the far-infrared radiation For the radiation layer 16, it is not necessary to use a binder or a substrate made of a material having low far-infrared radiation, such as low melting glass, and high radiation cooling performance can be obtained.

  Further, according to the far-infrared radiation cooling apparatus 10 of the present embodiment, the far-infrared radiation material is fixed to the surface of the heat transfer member 14 by spraying the far-infrared radiation material. Since a binder or base material made of a substance having low infrared radiation ability is not used, high radiation cooling performance can be obtained.

  Further, according to the far-infrared radiation cooling apparatus 10 of the present embodiment, the far-infrared radiation material constituting the far-infrared radiation layer 16 has a wavelength equal to or greater than the peak wavelength determined based on the actual temperature from the Wien's displacement law equation. Although it absorbs, it reflects an electromagnetic wave having a predetermined wavelength corresponding to visible, infrared, and far infrared, so that sufficient radiation cooling performance close to the theoretical limit can be obtained.

  Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

FIG. 3 shows an example in which the far-infrared radiation layer 16 corresponding to the far-infrared radiation cooling apparatus 10 is directly fixed to the bottom surface of the semiconductor 12. The semiconductor 12 of this embodiment is, for example, grown on a sapphire substrate and sprays a far-infrared radiation material at about 2 to 300 ° C. Semiconductor 12 constructed on a sapphire substrate, for example, does not become 250 ° C. or more, the electromagnetic radiation is not started, for example, it more fully also from far-infrared radiation layer 16 with CrO ₂ as a far-infrared radiating material Since radiation of electromagnetic waves is started at a low temperature, suitable radiation cooling can be obtained.

  FIG. 4 shows an example in which open circulation is provided with a fan 20 for forcibly supplying air to the heat transfer member 14 of the embodiment of FIG. In this case, the water vapor in the air absorbs the electromagnetic waves emitted from the far-infrared radiation layer 16, thereby promoting radiation cooling by the far-infrared radiation layer 16. In the present embodiment, the fan 20 functions as an electromagnetic wave absorbing means or device that absorbs electromagnetic waves emitted from the far-infrared radiation layer 16 with a fluid.

  FIG. 5 and FIG. 6 show the results of experiments conducted by the present inventor, and the temperature rise when the LED shown in FIG. 1 is used as a semiconductor 12 and operated under the following conditions is measured. It is. ◇ indicates that the far-infrared radiation layer 16 is not provided, □ indicates that the far-infrared radiation layer 16 is provided once by coating (average thickness is 5 to 15 μm), and Δ indicates that the coating is twice (average thickness is 10 to 30 μm), the cases where the far-infrared radiation layer 16 is provided are shown.

Operating conditions of experiment of FIG. 5 / wind speed 0.05-0.15 m / s
LED drive voltage: 6.30V
・ LED drive current: 700mA
・ Air temperature: 23 ℃
・ Air humidity: 31%

Operating conditions and wind speed of the experiment of FIG. 6 1.80-2.00 m / s
LED drive voltage: 6.30V
・ LED drive current: 700mA
・ Air temperature: 23 ℃
・ Air humidity: 31%

  At a low wind speed, as shown in FIG. 5, when the far-infrared radiation layer 16 is provided, the temperature of the semiconductor 12 is low, particularly when the far-infrared radiation layer 16 is not provided. When the far-infrared radiation layer 16 was provided (Δ mark), the temperature was lowered by 50 ° C. or more. At high wind speeds, as shown in FIG. 6, when the far-infrared radiation layer 16 is provided, the temperature of the semiconductor 12 is lower when the far-infrared radiation layer 16 is not provided. When the infrared radiation layer 16 was provided (□ mark), it was about 40 ° C. lower. When the far-infrared radiation layer 16 was provided by coating twice (Δ mark), it was about 30 ° C. lower.

  FIG. 7 shows an example in which closed circulation is provided with a fan 20 for forcibly supplying gas to the semiconductor 12 having the far-infrared radiation layer 16 provided on the back surface of the embodiment of FIG. In this case, a duct 22 that accommodates the semiconductor 12 and the fan 20 and a heat-dissipating heat exchanger 24 are provided in the circulation path, and an infrared absorbing gas 26 such as carbon dioxide or ammonia is circulated by the fan 20. In this embodiment, the fan 20 and the duct 22 function as an electromagnetic wave absorbing means or device that absorbs the electromagnetic wave radiated from the far-infrared radiation layer 16 with a fluid.

  According to the far-infrared radiation cooling apparatus 10 of the embodiment of FIGS. 4 and 7, the electromagnetic wave that is absorbed by the fluid from the far-infrared radiation layer 16 fixed to the surface or the lower surface of the heat transfer member 14 or the semiconductor 12. Since the absorption means or device is further provided, higher radiation cooling performance can be obtained.

(Experimental example 1)
An inverter IGBT for controlling a car air conditioner is put into practical use by being cooled by a water cooling device. When this estimation device is removed, the temperature becomes 120 ° C. or higher and the operation becomes impossible. However, as shown in the above-described embodiment, when the far-infrared radiation layer 16 was provided on one surface, the operating temperature was maintained at about 55 ° C. in the actual running state. Further, as in the embodiment shown in FIG. 7, when carbon dioxide gas was allowed to flow around the inverter IGBT, the operating temperature was about 40 ° C., and the car air conditioner operated in a normal operation.

(Experimental example 2)
The far-infrared radiation layer 16 was fixed to the back surface of a Pentium (Intel trademark) IV package operating at a clock frequency of 2.8 GHz and a driving voltage of 5 V, and the temperature rise was measured by performing a word processor operation of a normal personal computer. . Those in which the far-infrared radiation layer 16 was not fixed reached 100 ° C., but those in which the far-infrared radiation layer 16 was provided were maintained at 46 ° C.

  The above description is merely an example of the present invention, and the present invention can be variously modified without departing from the spirit of the present invention.

It is the schematic explaining the structure of the semiconductor provided with the far-infrared radiation cooling device of one Example of this invention. It is a figure which shows the radiant energy characteristic of the far-infrared radiation material which comprises the far-infrared radiation layer of the Example of FIG. It is the schematic explaining the structure of the semiconductor provided with the far-infrared radiation cooling device of the other Example of this invention, Comprising: It is a figure equivalent to FIG. It is a semiconductor provided with the far-infrared radiation cooling device of other examples of the present invention, and is a figure showing an example provided with a fan for open type forced air cooling. It is a figure which shows the experimental result of the low wind speed performed using the Example of FIG. 4 in order to show the cooling performance of a far-infrared radiation layer. It is a figure which shows the experimental result of the high wind speed performed using the Example of FIG. 4 in order to show the cooling performance of a far-infrared radiation layer. It is a semiconductor provided with the far-infrared radiation cooling device of other examples of the present invention, and is a figure showing an example provided with a fan of closed type fluid cooling.

Explanation of symbols

10: Far-infrared radiation cooling device 12: Semiconductor (heating element)
14: Heat transfer member 16: Far-infrared radiation layer

Claims (4)

A far-infrared radiation cooling apparatus comprising a far-infrared radiation layer composed of an aggregate of fine crystal grains of a far-infrared radiation material on a surface of a heat transfer member. The far-infrared radiation cooling device according to claim 1, wherein the far-infrared radiation material is fixed to the surface of the heat transfer member by spraying the far-infrared radiation material. The far-infrared radiation material absorbs a wavelength that is equal to or greater than the peak wavelength determined based on the actual temperature from the Wien's displacement law equation, but reflects an electromagnetic wave having a predetermined wavelength corresponding to visible, infrared, and far-infrared. The far-infrared radiation cooling device according to claim 1 or 2. 4. The far-infrared radiation cooling apparatus according to claim 1, further comprising electromagnetic wave absorbing means for absorbing electromagnetic waves radiated from a far-infrared radiation layer fixed to the surface of the heat transfer member by a fluid.

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