JP4682775B2 - Microchannel structure, heat exchange system, and electronic device - Google Patents

Description

  The present invention relates to a microchannel structure, a heat exchange system, and an electronic apparatus.

In recent years, as the density of semiconductors has increased, the amount of heat generated per unit volume has increased, and a cooling device having a heat sink and a fan has a problem of insufficient cooling capacity. Therefore, as a technique for cooling a semiconductor having a high heat generation density, a technique of flowing a refrigerant through a fine channel called a microchannel has been proposed (see, for example, Patent Document 1 and Patent Document 2). In the cooling mechanism of the multichip module described in Patent Document 1, a plurality of cooling fins are arranged in all regions inside the cooling mechanism, and a space between the cooling fins serves as a cooling channel.
In the cooling system described in Patent Document 2, a thin plate made of copper is used as a metal, and the flow path is formed by punching the thin plate into a square shape and stacking a plurality of sheets. Adjacent thin plates are joined by brazing.
JP-A-8-279578 JP 2005-166855 A

  However, the cooling system described in Patent Document 1 is based on copper as the material of the metal thin plate, and uses a brazing material to join the thin plates, so that the thermal conductivity between the thin plates decreases. End up. Further, even when such a cooling device is used for an electronic device or the like, the cooling becomes insufficient, and it is difficult to sufficiently exhibit the performance of the electronic device.

  The present invention has been made to solve the above problems, and an object thereof is to provide a microchannel structure, a heat exchange system, and an electronic device having high heat exchange efficiency.

In order to achieve the above object, the present invention provides the following means.
The microchannel structure of the present invention is a microchannel structure having a plurality of microchannels through which a fluid flows, and at least a wall portion of the microchannel in contact with the fluid is an array of the plurality of microchannels The heat conductivity in the direction perpendicular to the direction of arrangement of the fine flow paths is made of a material having a higher anisotropic thermal conductivity than the heat conductivity in the direction, and between the walls of the adjacent fine flow paths, The spacer is supported by a spacer, the wall portion is made of graphite, the spacer is made of copper, and in the arrangement direction, the thermal conductivity of the copper is larger than the thermal conductivity of the graphite, and the direction is perpendicular to the arrangement direction. The thermal conductivity of the graphite is larger than the thermal conductivity of the copper.
The microchannel structure of the present invention is a microchannel structure having a plurality of microchannels through which a fluid flows, and at least a wall portion of the microchannel in contact with the fluid is an array of the plurality of microchannels The thermal conductivity in the direction perpendicular to the arrangement direction of the microchannels is made of a material having a higher anisotropic thermal conductivity than the thermal conductivity in the direction.

  In the microchannel structure according to the present invention, the heat conductivity in the surface direction intersecting the arrangement direction of the microchannels is made of a material higher than the thermal conductivity in the arrangement direction of the microchannels. When placed in a direction perpendicular to the arrangement direction of the microchannels, the heat of the heat generating portion is transferred from the arrangement direction of the microchannels to the surface direction intersecting the arrangement direction of the microchannels. Therefore, the heat generated from the heat generating part is transmitted in a direction perpendicular to the heat generating part, and by flowing the fluid through the fine flow path, the heat of the heat generating part is transmitted to the fluid through the wall part, and the heat generating part is made efficient. It can cool well.

In the microchannel structure of the present invention, it is preferable that a space between the adjacent wall portions of the fine channels is supported by a spacer.
In the microchannel structure according to the present invention, for example, a sheet-like member made of a material having anisotropic thermal conductivity is used, and the space between the members is supported by a spacer, so that the heat generating portion is arranged in the direction in which the microchannels are arranged. When placed in a direction perpendicular to the heat generating portion, the heat generating portion can be efficiently cooled with a simple configuration.

In the microchannel structure of the present invention, the material is preferably graphite.
In the microchannel structure according to the present invention, for example, by using graphite having the characteristics that the thermal conductivity in the plane direction is 600 to 800 W / mK and the thermal conductivity in the thickness direction is 20 W / mK, Compared to the arrangement direction of the flow paths, the structure has a larger thermal conductivity in the plane direction intersecting the arrangement direction of the fine flow paths. As a result, the heat of the heat generating portion is transmitted in a direction perpendicular to the heat generating portion about twice as much as the thermal conductivity of copper 400 W / mK. Therefore, the thermal conductivity in the thickness direction is better for copper, but by using the method of the present invention using graphite, the fluid is allowed to flow through a plurality of microchannels, so that heat is generated in each microchannel. Conversion is performed, and the temperature rise of the heat generating portion can be significantly reduced. In addition, the graphite having anisotropic thermal conductivity is easy to process because it is lightweight. Furthermore, since graphite has good heat resistance, it is possible to efficiently transfer the heat of the heat generating part in the surface direction even when the heat generating part becomes high temperature.

  In the microchannel structure of the present invention, the opening shape of the microchannel in a cross section perpendicular to the fluid flow direction is such that the width in the direction perpendicular to the arrangement direction of the microchannels is the arrangement of the microchannels. It is preferably at least twice the width in the direction.

  In the microchannel structure according to the present invention, the width in the direction orthogonal to the arrangement direction is set to be twice or more the width in the arrangement direction of the microchannels, so that the heat generating part is compared with the case where copper is used. Heat spreads quickly in a direction perpendicular to the arrangement direction of the flow paths. Further, with the above configuration, the fluid can easily pass through the fine flow path, the flow velocity of the fluid flowing in the fine flow path can be reduced, and the pressure loss can be reduced. Detailed experimental results will be described later.

The heat exchange system according to the present invention is characterized in that a heat generating portion that generates heat is arranged in a direction perpendicular to the arrangement direction of the fine flow paths.
In the heat exchange system according to the present invention, the thermal conductivity in the plane direction intersecting the arrangement direction of the fine flow path is made of a material higher than the thermal conductivity in the arrangement direction of the fine flow path. The heat of the heat generating portion arranged in the direction perpendicular to the arrangement direction is transmitted from the arrangement direction of the fine flow passages in a plane direction intersecting the arrangement direction of the fine flow passages, that is, in a direction perpendicular to the heat generation portion. Become. Therefore, the heat generated from the heat generating part is transmitted in a direction perpendicular to the heat generating part, and by flowing the fluid through the fine channel, this heat is transmitted to the fluid, and the heat generating part can be efficiently cooled.

An electronic apparatus according to the present invention includes the above heat exchange system.
In the electronic device according to the present invention, the heat exchange system provided with the microchannel structure has a good heat exchange rate of the heat generating part as described above. Since the rise is suppressed, the characteristics are stable.

  Hereinafter, an embodiment of a microchannel structure and an electronic device according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

[First Embodiment]
1st Embodiment of the heat exchange system of this invention is described with reference to FIGS.
FIG. 1 is a perspective view illustrating a schematic configuration of a heat exchange system including a microchannel structure according to the present embodiment. 2 is a cross-sectional view of the microchannel structure of FIG. 1 taken along line AA. 3 is a BB line arrow view of the microchannel structure of FIG.
As shown in FIG. 2, the microchannel structure 10 is a structure including a plurality of fine flow paths 11 of several μm to several hundred μm in the arrangement direction, and a cooling medium (fluid) is supplied to the plurality of flow paths 11. By flowing, the heat of the heat generating part, which is an object to be cooled, is transferred to the fluid and heat exchange is performed.

As shown in FIGS. 2 and 3, the flow path 11 is formed by being partitioned by a plurality of wall portions 11 a extending in the Y direction and arranged at predetermined intervals in the X direction. The fluid flows in the flow path 11 in the extending direction of the wall portion 11a.
Further, the wall portion 11a of the flow channel 11 has a thermal conductivity in the plane direction (YZ axis plane) orthogonal to the arrangement direction of the flow channel 11 rather than the thermal conductivity in the arrangement direction of the flow channel 11, that is, the X direction. Is made of a material having a high anisotropic thermal conductivity. An example of this material is graphite. Graphite has a thermal conductivity in the X direction of about 20 W / mK, and a thermal conductivity in the Y-axis plane of about 600 to 800 W / mK. By using this graphite as the material of the microchannel structure 10, the heat generation part is arranged in a direction perpendicular to the arrangement direction of the flow paths 11, so that the heat generated from the heat generation part is orthogonal to the arrangement direction of the flow paths 11. It is easy to be transmitted in the surface direction.

  Further, as shown in FIG. 3, the opening shape of the flow path 11 orthogonal to the fluid flow direction has a width M in the direction orthogonal to the arrangement direction of the flow paths 11 with respect to the width L in the arrangement direction of the flow paths 11. It is about 8 times. Thus, by making the width M longer than the width L, it is possible to increase the surface area with a higher thermal conductivity of 600 to 800 W / mK, that is, the contact area with the fluid.

As shown in FIG. 1, an LED chip (heat generating part) 2 that is an object to be cooled is placed on the upper surface 10 a of the microchannel structure 10. The LED chip 2 is in contact with the upper surface 10 a of the microchannel structure 10 and is arranged in a direction perpendicular to the arrangement direction of the flow paths 11. Therefore, by flowing a fluid through the flow path 11, the heat of the LED chip 2 is transmitted to the fluid and heat exchange is performed.
Further, as shown in FIGS. 1 and 2, the side surface 10b of the microchannel structure 1 has a supply port 12 for supplying a fluid to the flow path 11 and a side surface 10c opposite to the side face 10b from the flow path 11. A discharge port 13 for discharging the fluid is formed.

  In the microchannel structure 10 according to the present embodiment, a material having anisotropic heat conduction characteristics is used, and the heat conduction in the surface direction orthogonal to the arrangement direction of the flow paths 11 is determined from the heat conductivity in the arrangement direction of the flow paths 11. The rate is configured to be higher. In particular, when graphite is used as a material having anisotropic heat conduction characteristics, the thermal conductivity in the plane direction intersecting the arrangement direction of the flow paths 11 is more than twice that of copper. Can be quickly transmitted in a direction perpendicular to the arrangement direction of the flow paths 11. Therefore, the heat generated from the LED chip 2 is transmitted in a direction perpendicular to the LED chip 2, and by flowing the fluid through the flow path 11, this heat is transmitted to the fluid and the LED chip 2 is efficiently cooled. Is possible.

  Moreover, since the width M in the direction perpendicular to the LED chip 2 is not less than twice the width L in the arrangement direction of the flow paths 11, the surface shape of the flow path 11 increases in the direction with high thermal conductivity. Therefore, the heat of the LED chip 2 quickly spreads in the surface direction orthogonal to the arrangement direction of the flow paths 11. Therefore, since the contact area between the heat and the fluid transmitted in the surface direction orthogonal to the arrangement direction of the flow paths 11 can be increased, the LED chip 2 can be efficiently cooled. Further, since the aspect ratio of the width L and the width M is about 8, the pressure loss of the fluid flowing through the flow path 11 can be reduced, so that the fluid can be effectively flowed through the flow path 11. .

[Second Embodiment]
Next, a second embodiment according to the present invention will be described with reference to FIG. In each embodiment described below, portions having the same configuration as those of the microchannel structure 10 according to the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.
The microchannel structure 20 according to the present embodiment is different from the first embodiment in that only the wall portion 21 of the flow path 11 is formed of graphite in the second embodiment.

As shown in FIG. 4, in the microchannel structure 20, sheet-like graphite is used for the wall portion 21, and a plurality of the wall portions 21 are provided in the X-axis direction at intervals. In addition, between the adjacent wall portions 21, spacers 22a and 22b made of copper are provided on both ends 21a and 21b side along the longitudinal direction (Y-axis direction), respectively. And the flow path 23 is each formed by the adjacent wall part 21, spacer 22a, and spacer 22b.
The LED chip 2 is disposed on the upper surface 20a of the microchannel structure 20 in which the wall portions 21 and the spacers 22a are alternately disposed.
As in the first embodiment, the wall portion 21 has heat in a plane direction (Y-axis plane) orthogonal to the arrangement direction of the flow paths 23 from the arrangement direction of the flow paths 23, that is, the thermal conductivity in the X direction. The conductivity is higher.

  In the microchannel structure 20 according to the present embodiment, since only the wall portion 21 of the adjacent flow path 23 is made of graphite having anisotropic thermal conductivity, the wall portion 21 is configured using sheet-like graphite. Thus, the LED chip 2 can be efficiently cooled with a simple configuration. Moreover, since the heat of the LED chip 2 can be spread also in the Y-axis direction between the adjacent wall portions 21, the heat of the LED chip 2 can be more effectively transferred to the fluid.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described with reference to FIGS.
In the microchannel structure 30 according to the present embodiment, the configuration of the supply port 32 of the side wall 31 on the fluid supply side and the discharge port 34 of the side wall 33 on the fluid discharge side are the same as those of the first and second embodiments. Different. That is, in the first and second embodiments, the supply port 12 and the discharge port 13 are provided on the side surface 10b and the side surface 10c of the microchannel structures 10 and 20, but in this embodiment, the supply port 32 and the discharge port 13 are provided. An outlet 34 is formed in the side wall portions 31 and 33.

FIG. 6 shows an exploded perspective view of the microchannel structure 30.
The side wall 31 and the side wall 33 are provided with a supply port 32 and a discharge port 34 made of copper at the center. Then, the side wall portion 31 and the side wall portion are formed by ring-shaped members 31a and 33a made of graphite provided around the supply port 32 and the discharge port 34, and fitting members 31b and 33b fitted to the members 31a and 33a. 33 is configured.

  In the microchannel structure 30 according to the present embodiment, the members 31a and 33a made of graphite and the fitting members 31b and 33b made of copper are alternately arranged around the supply port 32 and the discharge port 34 made of copper, and the side wall portion. By configuring 31 and the side wall 33, the heat spread in the Z-axis direction by the members 31a and 33a is further transmitted to the fitting members 31b and 33b, thereby efficiently transmitting the heat of the LED chip 2 to the fluid. It becomes possible.

[Fourth Embodiment]
Next, a fourth embodiment according to the present invention will be described with reference to FIG.
In the microchannel structure 40 according to the present embodiment, the side wall 41 and the supply port 42 on the fluid supply side are integrally formed, and the side wall 43 and the discharge port 44 on the side for discharging the fluid are formed. The point formed integrally is different from the first and second embodiments. That is, in this embodiment, the supply port 42 integrated with the side wall portion 41 and the discharge port 44 integrated with the side wall portion 43 are made of copper and are retrofitted to the microchannel structure 40. Yes.

  In the microchannel structure 40 according to the present embodiment, the side wall portion 41 and the supply port 42, and the side wall portion 43 and the discharge port 44 are integrally formed of copper, thereby forming the LED chip 2 with a simple configuration. Since heat can be spread as a whole, the heat of the LED chip 2 can be efficiently transferred to the fluid.

  In the third and fourth embodiments, the fitting members 31b and 33b, the supply port 42 integrated with the side wall 41, and the discharge port 44 integrated with the side wall 43 are described as members made of copper. However, the present invention is not limited to this, and a metal material having good conductivity can be used. For example, you may form with raw materials, such as aluminum, aluminum alloy, copper alloy, or stainless steel.

[Fifth Embodiment]
Next, as a fifth embodiment of the present invention, a projector including the light source device 100 having the microchannel structure 10 according to the first embodiment will be described.

  FIG. 8 is an explanatory diagram of a projector (electronic device) 500 including the microchannel structure 10 of the above embodiment. In the figure, reference numerals 512, 513, and 514 denote three light source devices provided with the microchannel structure 10 of the above embodiment, 522, 523, and 524 are liquid crystal light valves, 525 is a cross dichroic prism, and 526 is a projection lens. ing.

  Each light source device 512, 513, 514 employs LED chips that emit light in red (R), green (G), and blue (B), respectively. As a uniform illumination system for making the illuminance distribution of the light source light uniform, a rod lens or fly-eye lens may be arranged behind each light source device.

  The light beam from the red light source device 512 passes through the superimposing lens 535R, is reflected by the reflection mirror 517, and enters the liquid crystal light valve 522 for red light. The light beam from the green light source device 513 passes through the superimposing lens 535G and enters the green light liquid crystal light valve 523. The light beam from the blue light source device 514 passes through the superimposing lens 535B, is reflected by the reflecting mirror 516, and enters the blue light liquid crystal light valve 524. When a fly-eye lens is used as the uniform illumination system, the light flux from each light source is superimposed in the display area of the liquid crystal light valve through the superimposing lens, so that the liquid crystal light valve is illuminated uniformly. ing.

  In addition, polarizing plates (not shown) are arranged on the incident side and the emission side of each liquid crystal light valve. Then, only linearly polarized light in a predetermined direction out of the light flux from each light source passes through the incident side polarizing plate and enters each liquid crystal light valve. Further, a polarization conversion means (not shown) may be provided in front of the incident side polarizing plate. In this case, it is possible to recycle the light beam reflected by the incident-side polarizing plate and make it incident on each liquid crystal light valve, thereby improving the light utilization efficiency.

  The three color lights modulated by the liquid crystal light valves 522, 523, and 524 are incident on the cross dichroic prism 525. This prism is formed by bonding four right-angle prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are arranged in a cross shape on the inner surface thereof. These dielectric multilayer films combine the three color lights to form light representing a color image. The synthesized light is projected onto the projection screen 527 by the projection lens 526 which is a projection optical system, and an enlarged image is displayed.

  In the projector 500 according to the present embodiment described above, the LED chip 2 is cooled by the microchannel structure 10, so that a large current can be supplied and the brightness is increased. Therefore, by providing the light source device having the above-described microchannel structure 10, a projector having excellent display characteristics can be provided.

  Next, the aspect ratio of the width in the arrangement direction of the flow path and the width in the direction orthogonal to the arrangement direction of the flow path (dimension in the direction perpendicular to the arrangement direction of the flow path / dimension in the arrangement direction of the flow path) is specifically described. Explained.

  A microchannel structure made of graphite having an anisotropic thermal conductivity of 5 W / mK in the arrangement direction of the flow paths and 800 W / mK in the surface direction orthogonal to the arrangement direction of the flow paths; Comparison was made with a microchannel structure made of copper. The temperature of the heat generating part in each case where the aspect ratios of these microchannel structures were 2, 3, 4, 5, and 10 was obtained by simulation.

  As a result, as shown in FIG. 9, when the aspect ratio is 2 or more, the microchannel structure made of graphite transmits the heat of the heat generating portion more quickly in the plane direction perpendicular to the arrangement direction of the flow path than the copper. It can be seen that the temperature of the heat generating part is lowered. Therefore, by using a material with anisotropic thermal conductivity, such as graphite, for the microchannel structure and arranging the heat generating part so as to intersect the surface direction with high thermal conductivity, the cooling efficiency of the heat generating part is improved. It becomes possible to improve. Therefore, in each of the above embodiments, the microchannel structure having an aspect ratio of about 8 between the width L in the arrangement direction of the flow paths 11 and the width M in the direction orthogonal to the arrangement direction of the flow paths is described. Two or more is sufficient.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, although the LED chip 2 has been described as the object to be cooled, the present invention is not limited to this, and a heat source that requires cooling can be placed on the upper surface 10a of the microchannel structure 10.
Moreover, although the adjacent wall parts 11a and 21 were made of graphite, at least the wall part of the flow path 11 in contact with the fluid is in the arrangement direction of the flow paths 11 from the thermal conductivity in the arrangement direction of the plurality of flow paths 11. It suffices to be made of a material having anisotropic thermal conductivity that is higher in the vertical direction. Further, although graphite is used as a material having anisotropic thermal conductivity, it is not limited to this.

1 is a perspective view showing a microchannel structure according to a first embodiment of the present invention. It is an AA arrow directional view of the microchannel structure of FIG. It is a BB line arrow directional view of the microchannel structure of Drawing 1. It is sectional drawing which shows the microchannel structure which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the microchannel structure which concerns on 3rd Embodiment of this invention. FIG. 6 is an exploded perspective view of the microchannel structure of FIG. 5. It is sectional drawing which shows the microchannel structure which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the electronic device which concerns on 5th Embodiment of this invention. It is a graph which shows the case where graphite and copper are used for the microchannel structure of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 20, 30, 40 ... Microchannel structure, 11 ... Flow path, 11a ... Wall part, 21 ... Wall part, 22a, 22b ... Spacer, 500 ... Projector (electronic device)

Claims (4)

A microchannel structure having a plurality of fine channels through which a fluid flows,
At least the wall portion of the microchannel that contacts the fluid has a higher thermal conductivity in the direction perpendicular to the arrangement direction of the microchannels than the thermal conductivity in the arrangement direction of the plurality of microchannels. Ri Do a material having anisotropic thermal conductivity,
Between the adjacent wall portions of the fine channel is supported by a spacer,
The wall is made of graphite, the spacer is made of copper,
The thermal conductivity of the copper is greater than the thermal conductivity of the graphite in the arrangement direction, and the thermal conductivity of the graphite is greater than the thermal conductivity of the copper in a direction perpendicular to the arrangement direction. Microchannel structure. The opening shape of the fine channel in the cross section perpendicular to the fluid flow direction is such that the width in the direction perpendicular to the arrangement direction of the fine channel is at least twice the width in the arrangement direction of the fine channel. The microchannel structure according to claim 1 , wherein A heat exchange system comprising the microchannel structure according to claim 1 or 2,
Wherein in a direction perpendicular to the arrangement direction of the micro channel heat exchanger system that is characterized in that the heating portion is disposed to heat generation of the microchannel structure. An electronic apparatus comprising the heat exchange system according to claim 3 .

Images