WO2021240631A1 - Cooling device - Google Patents

Abstract

A cooling device (1) is provided with a container (10), a heat dissipation member (18), a bubble generation unit (23), and a heating unit (20). A liquid (17) is sealed in the container (10). The container (10) includes a mounting surface (11c) on which a heating body (3) is mounted. The heat dissipation member (18) is mounted on the container (10). The bubble generation unit (23) is supported by the container (10) and is in contact with the liquid (17). The heating unit (20) heats the bubble generation unit (23). The bubble generation unit (23) generates, in the liquid (17), a bubble fixed to the bubble generation unit (23). Marangoni convection (26) is produced in the liquid (17) around the bubble (25).

Description

Cooling system

This disclosure relates to a cooling device.

Japanese Unexamined Patent Publication No. 2019-103269 (Patent Document 1) discloses a heat radiating unit that cools a power conversion device. The power conversion device includes a heat receiving plate and a plurality of semiconductor elements designated by the heat receiving plate. The heat radiating unit includes a pipe provided on the heat receiving plate, a pump, and a heat exchanger. The pump is connected to the pipe and circulates the coolant in the pipe. The heat exchanger is connected to the piping and cools the coolant warmed by the heat receiving plate.

Japanese Unexamined Patent Publication No. 2019-103269

In the heat dissipation part of Patent Document 1, a pump is used to circulate the coolant in the pipe. Therefore, the size of the heat radiating portion of Patent Document 1 is large, and the power consumption of the heat radiating portion of Patent Document 1 is large. Further, since the pump includes a mechanically movable part, the reliability of the heat radiating part of Patent Document 1 is low. The present disclosure has been made in view of the above problems, and an object thereof is to provide a cooling device having a more compact size, higher reliability, and reduced power consumption.

The cooling device of the present disclosure includes a container, a heat radiating member, a first bubble generating unit, and a first heating unit. The container is filled with liquid. The container includes a mounting surface to which the heating element is attached directly or via a heat conductive member. The heat dissipation member is attached to the container either directly or via a heat transfer member. The first bubble generating portion is supported by the container and is in contact with the liquid. The first heating unit heats the first bubble generation unit. The first bubble generation unit generates the first bubble fixed to the first bubble generation unit in the liquid. The first Marangoni convection is generated in the liquid around the first bubble.

The energy applied to the first heating unit to generate the first bubble and the first Marangoni convection is smaller than the energy required to drive the pump that circulates the coolant. Therefore, the power consumption of the cooling device can be reduced. The size of the first heating section and the first bubble generating section required to generate the first bubble and the first Marangoni convection is smaller than the size of the pump. Therefore, the cooling device has a more compact size. The first heating section and the first bubble generating section required to generate the first bubble and the first marangoni convection do not include the mechanically movable section. Therefore, the cooling device has higher reliability.

It is a schematic sectional drawing of the cooling apparatus of Embodiment 1. FIG. It is a schematic partial enlarged sectional view in the region II shown in FIG. 1 of the cooling apparatus of Embodiment 1. FIG. Is a diagram illustrating a change in the thermal resistance R ₁ with respect to the distance L of the cooling apparatus of Example 1 of the first embodiment, a graph showing a simulation of a change result of the thermal resistance R ₁ with respect to the distance L of the cooling device of the comparative example. It is schematic sectional drawing of the cooling apparatus of the 1st modification of Embodiment 1. FIG. It is a schematic partial enlarged sectional view of the cooling device of the 2nd modification of Embodiment 1. FIG. It is schematic sectional drawing of the cooling apparatus of the 3rd modification of Embodiment 1. FIG. It is schematic sectional drawing of the cooling apparatus of the 4th modification of Embodiment 1. FIG. It is a schematic partial enlarged sectional view of the cooling apparatus of Embodiment 2. FIG. It is a schematic partial enlarged sectional view of the cooling apparatus of Embodiment 3. FIG. It is a schematic partial enlarged sectional view of the cooling apparatus of Embodiment 4. FIG. It is a schematic partial enlarged sectional view of the cooling device of the modification of Embodiment 4. FIG. It is a schematic partial enlarged sectional view of the cooling apparatus of Embodiment 5. FIG. It is a schematic partial enlarged sectional view of the cooling device of the modification of Embodiment 5. FIG. 3 is a schematic cross-sectional view of the cooling device of the sixth embodiment. FIG. 3 is a schematic cross-sectional view of the cooling device according to the seventh embodiment. FIG. 3 is a schematic cross-sectional view of the cooling device of the eighth embodiment. It is a schematic sectional drawing of the cooling apparatus of Embodiment 9. FIG. The cooling device of Example 2 of Embodiment 9 is a diagram illustrating simulation results of the thermal resistance R ₂ to the thickness t of the channel. 9 is a schematic cross-sectional view of the cooling device of the first modification of the ninth embodiment. It is schematic sectional drawing of the cooling apparatus of the 2nd modification of Embodiment 9. FIG. FIG. 3 is a schematic cross-sectional view of the cooling device of the tenth embodiment. It is the schematic sectional drawing of the cooling apparatus of the modification of Embodiment 10.

Hereinafter, embodiments of the present disclosure will be described. The same reference number is assigned to the same configuration, and the description thereof will not be repeated.

Embodiment 1.
The cooling device 1 of the first embodiment will be described with reference to FIGS. 1 to 3. The cooling device 1 cools the heating element 3. The heating element 3 is, for example, an electronic device or an electronic element. Electronic devices are, for example, power converters, power electronics devices for automobiles, high-speed communication devices for mobile phones or satellite communications, or laser oscillators. The electronic element is, for example, a transistor such as an insulated gate bipolar transistor (IGBT).

The cooling device 1 mainly includes a container 10, a heat radiating member 18, a heating unit 20, and a bubble generating unit 23.

The container 10 is made of, for example, a high thermal conductive material having a thermal conductivity of 1.0 W / (m · K) or more. The container 10 may be formed of a high thermal conductive material having a thermal conductivity of 5.0 W / (m · K) or more, and may be made of a high thermal conductive material having a thermal conductivity of 10.0 W / (m · K) or more. It may be formed or may be formed of a high thermal conductivity material having a thermal conductivity of 50.0 W / (m · K) or more, and may be formed of a high thermal conductivity having a thermal conductivity of 100.0 W / (m · K) or more. It may be formed of a material. The container 10 is made of, for example, a metal such as copper, aluminum or stainless steel, or a resin.

The liquid 17 is sealed in the container 10. The container 10 may be filled with the liquid 17. The liquid 17 is a cooling liquid such as water, alcohol, ammonia, oil or a chlorofluorocarbon-based liquid.

The container 10 includes a first wall 11, a second wall 12 facing the first wall 11, and a third wall 13 connecting the first wall 11 and the second wall 12 to each other. The first wall 11 includes a first inner wall surface 11b that comes into contact with the liquid 17 and a first outer wall surface 11a that is opposite to the first inner wall surface 11b. The second wall 12 includes a second inner wall surface 12b that is in contact with the liquid 17 and faces the first inner wall surface 11b, and a second outer wall surface 12a that is opposite to the second inner wall surface 12b. The first wall 11, the second wall 12, and the third wall 13 define an internal cavity of the container 10.

The thickness of the walls (first wall 11, second wall 12, third wall 13) constituting the container 10 is, for example, less than 1000 μm. The thickness of the walls (first wall 11, second wall 12, third wall 13) constituting the container 10 may be 800 μm or less, 500 μm or less, or 300 μm or less. .. As will be described later, the bubble 25 formed in the bubble generating section 23 by heating the bubble generating section 23 is a minute bubble fixed to the bubble generating section 23 and is a liquid around the bubble generating section 25. Let 17 generate the first Marangoni convection. Even if the bubbles 25 are generated, the internal pressure of the container 10 hardly rises. Therefore, the thickness of the walls (first wall 11, second wall 12, third wall 13) constituting the container 10 can be reduced. Further, by reducing the thickness of the walls (first wall 11, second wall 12, third wall 13) constituting the container 10, the thermal resistance between the heating element 3 and the liquid 17 and the liquid 17 can be obtained. The thermal resistance between the heat radiating member 18 and the heat radiating member 18 can be reduced.

The thickness of the walls (first wall 11, second wall 12, third wall 13) constituting the container 10 is, for example, 10 μm or more. The thickness of the walls (first wall 11, second wall 12, third wall 13) constituting the container 10 may be, for example, 50 μm or more, or 100 μm or more. Therefore, it is possible to prevent the liquid 17 from leaking out of the container due to the walls (first wall 11, second wall 12, and third wall 13) constituting the container 10 being torn.

The container 10 includes a mounting surface 11c to which the heating element 3 is mounted. In one example, the first outer wall surface 11a includes a mounting surface 11c. The heating element 3 may be directly attached to the mounting surface 11c using, for example, an adhesive or a fixing member (not shown) such as a screw.

The heat radiating member 18 is attached to the container 10. In one example, the heat radiating member 18 is attached to the second outer wall surface 12a. The heat radiating member 18 is, for example, a heat radiating fin or a heat sink. A surface layer that promotes heat dissipation may be formed on the surface of the heat dissipation member 18. The surface layer may be, for example, a coating film that promotes heat dissipation (for example, a black coating film), or may be a surface treatment layer such as an alumite treatment layer. The heat radiating member 18 may be directly attached to the container 10 (for example, the second outer wall surface 12a) by using a fixing member (not shown) such as an adhesive or a screw.

The heating unit 20 is supported by the container 10. In one example, the heating unit 20 is provided on the first outer wall surface 11a. The heating unit 20 is, for example, a micro heater or a thin film heater. By supplying an electric current to the heating unit 20 from a current source (not shown), heat is generated in the heating unit 20. This heat is conducted to the bubble generating portion 23 through the container 10 (first wall 11). In this way, the heating unit 20 heats the bubble generation unit 23.

The area of the heating unit 20 has an area of 1.0 mm ² or less. The area of the heating unit 20 may be 0.5 mm ² or less, 0.2 mm ² or less, ^{or 0.1 mm 2} or less. In the present embodiment, the area of the heating unit 20 is the area of the heating unit 20 in the plan view of the first outer wall surface 11a. The area of the heating unit 20 is smaller than the area of the heating element 3, and the thickness of the heating unit 20 is smaller than the thickness of the heating element 3. The area of the heating portion 20 is smaller than the area of the mounting surface 11c.

The amount of heat generated in the heating unit 20 can be ignored with respect to the amount of heat generated in the heating element 3. The amount of heat generated by the heating unit 20 is, for example, less than one-twentieth of the amount of heat generated by the heating element 3. The amount of heat generated by the heating unit 20 may be one-hundredth or less of the amount of heat generated by the heating element 3. The amount of heat generated by the heating unit 20 is, for example, 50 mW or less. The amount of heat generated by the heating unit 20 may be 30 mW or less. The amount of heat generated by the heating element 3 is, for example, 1 W or more. The amount of heat generated by the heating element 3 may be 100 W or more.

The bubble generation unit 23 is supported by the container 10. In one example, the bubble generation unit 23 is provided on the first inner wall surface 11b. The bubble generation unit 23 is in contact with the liquid 17. The bubble generation unit 23 is, for example, a bubble generation film. The bubble generation unit 23 is made of, for example, copper or aluminum. The bubble generation unit 23 may be formed of a material different from that of the container 10, or may be formed of the same material as the container 10.

The area of the bubble generating section 23 (the area of the bubble fixing surface of the bubble generating section 23) has an area of 1.0 mm ² or less. The area of the bubble generating portion 23 may be 0.5 mm ² or less, 0.2 mm ² or less, ^{or 0.1 mm 2} or less. In the present embodiment, the area of the bubble generating portion 23 is the area of the bubble generating portion 23 in the plan view of the first inner wall surface 11b. The area of the bubble generating section 23 (the bubble fixing surface of the bubble generating section 23) is smaller than the area of the heating element 3, and the thickness of the bubble generating section 23 is smaller than the thickness of the heating element 3. The area of the bubble generating portion 23 is smaller than the area of the mounting surface 11c.

The bubble generation unit 23 is heated by the heating unit 20 to generate bubbles 25 in the liquid 17. The bubble 25 is fixed to the bubble generation unit 23. The bubble 25 is a minute bubble. The diameter of the bubble 25 is, for example, 100 μm or less. The diameter of the bubble 25 is, for example, 10 μm or more. As will be described in detail later, the Marangoni convection 26 is generated in the liquid 17 around the bubble 25.

The cooling action of the heating element 3 by the cooling device 1 of the present embodiment will be described.
When the liquid 17 is injected into the container 10, seed bubbles (not shown) adhere to the surface of the bubble generating portion 23 in contact with the liquid 17. The seed bubble is a bubble that is much smaller than the bubble 25. Heat is generated in the heating unit 20. This heat is conducted to the bubble generating portion 23 through the container 10 (first wall 11). The bubble generation unit 23 is heated by the heating unit 20. When the bubble generation unit 23 is heated by the heating unit 20, the seed bubbles expand and the bubbles 25 adhering to the bubble generation unit 23 are generated in the liquid 17.

The temperature of the liquid 17 around the bubble 25 rises as it approaches the bubble generating section 23. As the distance from the bubble generator 23 increases, the temperature of the liquid 17 around the bubble 25 decreases. Generally, as the temperature of the liquid 17 rises, the surface tension of the liquid 17 decreases. As it approaches the bubble generator 23, the surface tension of the liquid 17 around the bubble 25 decreases. As the distance from the bubble generator 23 increases, the surface tension of the liquid 17 around the bubble 25 increases. Due to the distribution of the surface tension of the liquid 17 around the bubble 25, the marangoni convection 26 is generated in the liquid 17 around the bubble 25.

Due to the Marangoni convection 26, a flow 27 having a large flow velocity is generated in the liquid 17. The speed of the flow 27 is, for example, 1.0 m / sec or more. The flow 27 causes the liquid 17 to hit the second wall 12. Since the heat radiating member 18 is attached to the second wall 12, the liquid 17 that hits the second wall 12 is cooled by the second wall 12 and the heat radiating member 18. Of the liquid 17 around the bubble 25, the temperature rise of the liquid 17 distal to the bubble generating portion 23 is suppressed. The temperature distribution of the liquid 17 around the bubbles 25 is maintained. In this way, the bubble 25 is fixed to the bubble generating section 23 without being separated from the bubble generating section 23.

The liquid 17 circulates in the container 10 at high speed by the flow 27. A part of the liquid 17 that has been cooled by hitting the second wall 12 hits a portion of the container 10 in which the mounting surface 11c is formed (for example, the first wall 11 of the container 10). The heat generated by the heating element 3 is transferred to the container 10 and the liquid 17. In the liquid 17, the heat generated by the heating element 3 can be dissipated in a short time. The liquid 17 that circulates in the container 10 at high speed functions as a heat spreader. Further, the temperature of the portion of the container 10 to which the heating element 3 is attached is higher than the temperature of the other portion of the container 10. Therefore, the flow 27 of the liquid 17 is disturbed in the portion of the container 10 to which the heating element 3 is attached, and is agitated in the container 10. The heat transfer coefficient of the liquid 17 that circulates in the container 10 at high speed and is agitated in the container 10 is large. In this way, the heat generated in the heating element 3 is cooled by the container 10 and the liquid 17.

_{As shown in FIG. 3, the thermal resistance R 1} of the cooling device 1 of the first embodiment of the present embodiment is lower than _{the thermal resistance R 1} of the cooling device of the comparative example for any distance L. The reason is that, as already described, in the cooling device 1 of the present embodiment, the liquid 17 that circulates in the container 10 at high speed and is agitated in the container 10 has the ability to spread the heat generated by the heating element 3. This is because it is high and has a large heat transfer coefficient. In the cooling device 1 of the first embodiment of the present embodiment, the container 10 is made of copper and the liquid 17 is water. The cooling device of the comparative example has the same configuration as the cooling device 1 of the present embodiment, but the liquid 17 is replaced with a copper plate, and this copper plate is integrated with the container 10 and is heated. The unit 20 and the bubble generation unit 23 have been removed.

As shown in FIG. 1, the thermal resistance R ₁ is on the second outer wall surface 12a to which the heat dissipation member 18 is mounted and the intersection 11p between the first outer wall surface 11a including the mounting surface 11c and the center line 3p of the heating element 3 is mounted. Thermal resistance between any point 12q. The distance L means the distance from the intersection 12p of the center line 3p of the heating element 3 and the second outer wall surface 12a to an arbitrary point 12q on the second outer wall surface 12a. The center line 3p of the heating element 3 is a line that passes through the center of the heating element 3 in the plan view of the first outer wall surface 11a and is perpendicular to the first outer wall surface 11a.

Further, as the distance L increases, the thermal resistance of the cooling device of the comparative example greatly increases. On the other hand, even if the distance L increases, the thermal resistance of the cooling device 1 of the first embodiment of the present embodiment hardly increases. The reason is that in the cooling device 1 of the present embodiment, the liquid 17 that circulates in the container 10 at high speed and is agitated in the container 10 has a high ability to spread the heat generated by the heating element 3 and is large. This is because it has a heat transfer coefficient.

With reference to FIG. 4, the cooling device 1b of the first modification of the present embodiment will be described. In the cooling device 1b, the heating unit 20 is, for example, a light absorbing film such as a gold nano-thin film. The gold nanothin film can be formed, for example, by a dynamic orthorhombic deposition method. The heating unit 20 absorbs light (for example, laser light) emitted from a light source 21 such as a semiconductor laser, and heat is generated in the heating unit 20. This heat is conducted to the bubble generating portion 23 through the container 10 (first wall 11). In this way, the heating unit 20 heats the bubble generation unit 23.

As in the cooling device 1c of the second modification of the present embodiment shown in FIG. 5, the bubble fixing surface of the bubble generation unit 23 is flush with the inner wall surface of the container 10 (for example, the first inner wall surface 11b). There may be.

The heating element 3 may be attached to the mounting surface 11c of the container 10 via the heat conductive member 30 as in the cooling device 1d of the third modification of the present embodiment shown in FIG. The heat conductive member 30 may be a heat pipe or a heat transfer plate such as a copper plate, an aluminum plate or a graphite plate, or may be a heat conductive adhesive such as heat conductive grease.

Even if the heat radiating member 18 is attached to the container 10 (for example, the second outer wall surface 12a) via the heat transfer member 30e as in the cooling device 1e of the fourth modification of the present embodiment shown in FIG. good. The heat transfer member 30e may be a heat pipe, a heat transfer plate such as a copper plate, an aluminum plate or a graphite plate, or a heat transfer adhesive such as a heat transfer grease.

The effects of the cooling devices 1, 1b, 1c, 1d, and 1e of the present embodiment will be described.
The cooling devices 1, 1b, 1c, 1d, 1e of the present embodiment include a container 10, a heat radiating member 18, a first bubble generating section (bubble generating section 23), and a first heating section (heating section 20). To prepare for. The liquid 17 is sealed in the container 10. The container 10 includes a mounting surface 11c to which the heating element 3 is mounted directly or via a heat conductive member 30. The heat radiating member 18 is attached directly to the container 10 or via the heat transfer member 30e. The first bubble generating portion is supported by the container 10 and is in contact with the liquid 17. The first heating unit heats the first bubble generation unit. The first bubble generation unit generates first bubbles (bubbles 25) fixed to the first bubble generation unit in the liquid 17. The first Marangoni convection (Marangoni convection 26) is generated in the liquid 17 around the first bubble.

The energy applied to the first heating unit (heating unit 20) to generate the first bubble (bubble 25) and the first marangoni convection (marangoni convection 26) is required to drive the pump that circulates the coolant. Energy is much smaller than the energy. Therefore, the power consumption of the cooling devices 1, 1b, 1c, 1d, 1e can be reduced. The size of the first heating unit (heating unit 20) and the first bubble generation unit (bubble generation unit 23) required to generate the first bubble and the first marangoni convection is much smaller than the size of the pump. Therefore, the cooling devices 1, 1b, 1c, 1d, 1e have a more compact size. The first heating section and the first bubble generating section required to generate the first bubble and the first marangoni convection do not include the mechanically movable section. Therefore, the cooling devices 1, 1b, 1c, 1d, 1e have higher reliability.

In the cooling devices 1, 1b, 1c, 1d, 1e of the present embodiment, the container 10 includes a first wall 11 and a second wall 12 facing the first wall 11. The first wall 11 includes a first inner wall surface 11b that comes into contact with the liquid 17 and a first outer wall surface 11a that is opposite to the first inner wall surface 11b. The second wall 12 includes a second inner wall surface 12b that is in contact with the liquid 17 and faces the first inner wall surface 11b, and a second outer wall surface 12a that is opposite to the second inner wall surface 12b. The first outer wall surface 11a includes a mounting surface 11c. The first bubble generation unit (bubble generation unit 23) is provided on the first inner wall surface 11b. The first heating unit (heating unit 20) is provided on the first outer wall surface 11a. The heat radiating member 18 is attached directly to the second outer wall surface 12a or via the heat transfer member 30e.

Therefore, the cooling devices 1, 1b, 1c, 1d, 1e have a more compact size and higher reliability, and the power consumption of the cooling devices 1, 1b, 1c, 1d, 1e can be reduced.

Embodiment 2.
The cooling device 1f of the second embodiment will be described with reference to FIG. The cooling device 1f of the present embodiment has the same configuration as the cooling device 1 of the first embodiment, but is different from the cooling device 1 of the first embodiment mainly in the following points.

In the cooling device 1f, a recess 24 is formed on the bubble fixing surface of the bubble generating portion 23. The recess 24 may be a V-groove. The maximum size of the recess 24 is smaller than the diameter of the bubble 25. The maximum size of the recess 24 is, for example, 50 μm or less. The maximum size of the recess 24 may be 30 μm or less, or 20 μm or less. When the recess 24 is a V-groove, the maximum size of the recess 24 is the size of the V-groove on the bubble fixing surface of the bubble generating portion 23.

In the modification of the present embodiment, instead of the recess 24, the surface of the support member (first wall 11) of the container 10 that supports the bubble generation portion 23 is placed on the bubble fixing surface of the bubble generation portion 23 (for example, the first one). A rough surface coarser than the inner wall surface 11b) may be formed. The bubble generation unit 23 is a porous body, and the surface of the porous body is rougher than the surface (for example, the first inner wall surface 11b) of the support member (first wall 11) of the container 10 that supports the bubble generation unit 23. It may be a rough surface.

The effect of the cooling device 1f of the present embodiment has the following effects in addition to the effect of the cooling device 1 of the first embodiment.

In the cooling device 1f of the present embodiment, the bubble fixing surface of the first bubble generating section (bubble generating section 23) has a rough surface or a recess 24 rougher than the surface of the support member of the container 10 that supports the first bubble generating section. It is formed.

Therefore, when the liquid 17 is injected into the container 10, seed bubbles (not shown) adhere to the bubble fixing surface of the first bubble generation section (bubble generation section 23) more reliably. When the first bubble generation section is heated by the first heating section (heating section 20), the seed bubbles expand and the first bubble (bubble 25) is more reliably generated in the first bubble generation section. The first Marangoni convection (Marangoni convection 26) is more reliably generated in the liquid 17 around the first bubble. Due to the first Marangoni convection, the flow 27 of the liquid 17 is more reliably generated. The cooling device 1f can more reliably cool the heating element 3.

Embodiment 3.
The cooling device 1g of the third embodiment will be described with reference to FIG. The cooling device 1g of the present embodiment has the same configuration as the cooling device 1 of the first embodiment, but is different from the cooling device 1 of the first embodiment mainly in the following points.

In the cooling device 1g, the bubble generating portion 23 overlaps the heating element 3 in the first plan view of the first outer wall surface 11a. In the first plan view of the first outer wall surface 11a, the heating unit 20 overlaps the heating element 3. Specifically, in the first plan view of the first outer wall surface 11a, the bubble generating portion 23 is surrounded by the outer shape of the heating element 3. In the first plan view of the first outer wall surface 11a, the heating unit 20 is surrounded by the outer shape of the heating element 3.

The effect of the cooling device 1g of the present embodiment has the following effects in addition to the effect of the cooling device 1 of the first embodiment.

In the cooling device 1g of the present embodiment, the first bubble generating section (bubble generating section 23) overlaps the heating element 3 in the first plan view of the first outer wall surface 11a. Therefore, the first bubble generation unit is heated by the heating element 3 in addition to the first heating unit (heating unit 20). The energy applied to the first heating section to generate the first bubble (bubble 25) and the first marangoni convection (marangoni convection 26) can be reduced. The power consumption of the cooling device 1g can be further reduced.

Embodiment 4.
The cooling device 1h of the fourth embodiment will be described with reference to FIG. The cooling device 1h of the present embodiment has the same configuration as the cooling device 1 of the first embodiment, but is different from the cooling device 1 of the first embodiment mainly in the following points.

In the cooling device 1h, the first wall 11 includes the first wall base member 11d and the high thermal conductive wall portion 11e. The high thermal conductivity wall portion 11e has a higher thermal conductivity than the first wall base member 11d. For example, when the first wall base member 11d is made of aluminum, the high thermal conductive wall portion 11e is made of copper. The high heat conduction wall portion 11e is provided between the bubble generation section 23 and the heating section 20. The high thermal conduction wall portion 11e may come into contact with the bubble generation portion 23 and the heating portion 20. The bubble generation unit 23 may be provided on the high heat conduction wall portion 11e. The heating unit 20 may be provided on the high heat conduction wall portion 11e.

With reference to FIG. 11, the cooling device 1i of the modified example of the present embodiment will be described. The first wall 11 further includes a low thermal conductivity wall portion 11f having a lower thermal conductivity than the first wall base member 11d. For example, when the first wall base member 11d is made of aluminum, the high thermal conductive wall portion 11e is made of copper and the low thermal conductive portion is made of stainless steel, titanium or resin. The low thermal conductive wall portion 11f is provided between the first wall base member 11d and the high thermal conductive wall portion 11e. The bubble generation unit 23 may be separated from the low heat conduction wall portion 11f. The heating unit 20 may be separated from the low heat conduction wall portion 11f.

The effects of the cooling devices 1h and 1i of the present embodiment have the following effects in addition to the effects of the cooling device 1 of the first embodiment.

In the cooling devices 1h and 1i of the present embodiment, the first wall 11 includes a first wall base member 11d and a high thermal conductivity wall portion 11e having a higher thermal conductivity than the first wall base member 11d. The high heat conduction wall portion 11e is provided between the first bubble generation section (bubble generation section 23) and the first heating section (heating section 20). Therefore, the heat generated in the first heating section is transferred to the first bubble generation section through the high heat conduction wall portion 11e. The energy applied to the first heating section to generate the first bubble (bubble 25) and the first marangoni convection (marangoni convection 26) can be reduced. The power consumption of the cooling devices 1h and 1i can be further reduced.

In the cooling device 1i of the present embodiment, the first wall 11 further includes a low thermal conductivity wall portion 11f having a thermal conductivity lower than that of the first wall base member 11d. The low thermal conductive wall portion 11f is provided between the first wall base member 11d and the high thermal conductive wall portion 11e. Therefore, the low thermal conductive wall portion 11f reduces the amount of heat dissipated from the first heating portion (heating portion 20) to the first wall base member 11d. The energy applied to the first heating section to generate the first bubble (bubble 25) and the first marangoni convection (marangoni convection 26) can be reduced. The power consumption of the cooling device 1i can be further reduced.

Embodiment 5.
The cooling device 1j of the fifth embodiment will be described with reference to FIG. The cooling device 1j of the present embodiment has the same configuration as the cooling device 1 of the first embodiment, but is different from the cooling device 1 of the first embodiment mainly in the following points.

In the cooling device 1j, the heating unit 20 is provided on the first inner wall surface 11b. The bubble generation unit 23 is provided on the heating unit 20.

With reference to FIG. 13, the cooling device 1k of the modified example of the present embodiment will be described. Similar to the cooling device 1g of the third embodiment, in the cooling device 1k, the bubble generating unit 23 overlaps the heating element 3 in the first plan view of the first outer wall surface 11a. In the first plan view of the first outer wall surface 11a, the heating unit 20 overlaps the heating element 3. Specifically, in the first plan view of the first outer wall surface 11a, the bubble generating portion 23 is surrounded by the outer shape of the heating element 3. In the first plan view of the first outer wall surface 11a, the heating unit 20 is surrounded by the outer shape of the heating element 3.

The effects of the cooling devices 1j and 1k of the present embodiment have the following effects in addition to the effects of the cooling device 1 of the first embodiment.

In the cooling devices 1j and 1k of the present embodiment, the container 10 includes a first wall 11 and a second wall 12 facing the first wall 11. The first wall 11 includes a first inner wall surface 11b that comes into contact with the liquid 17 and a first outer wall surface 11a that is opposite to the first inner wall surface 11b. The second wall 12 includes a second inner wall surface 12b that is in contact with the liquid 17 and faces the first inner wall surface 11b, and a second outer wall surface 12a that is opposite to the second inner wall surface 12b. The first outer wall surface 11a includes a mounting surface 11c. The first heating unit (heating unit 20) is provided on the first inner wall surface 11b. The first bubble generation unit (bubble generation unit 23) is provided on the first heating unit. The heat radiating member 18 is attached directly to the second outer wall surface 12a or via the heat transfer member 30e (see FIG. 7).

Therefore, the heat generated in the first heating unit (heating unit 20) is transferred to the first bubble generation unit (bubble generation unit 23) without passing through the first wall 11. The energy applied to the first heating section to generate the first bubble (bubble 25) and the first marangoni convection (marangoni convection 26) can be reduced. The power consumption of the cooling devices 1j and 1k can be further reduced.

In the cooling device 1k of the present embodiment, the first bubble generating section (bubble generating section 23) overlaps the heating element 3 in the first plan view of the first outer wall surface 11a. Therefore, the first bubble generation unit is heated by the heating element 3 in addition to the first heating unit (heating unit 20). The energy applied to the first heating section to generate the first bubble (bubble 25) and the first marangoni convection (marangoni convection 26) can be reduced. The power consumption of the cooling device 1k can be further reduced.

Embodiment 6.
The cooling device 1 m according to the sixth embodiment will be described with reference to FIG. The cooling device 1m of the present embodiment has the same configuration as the cooling device 1 of the first embodiment, but is different from the cooling device 1 of the first embodiment mainly in the following points.

In the cooling device 1 m of the present embodiment, the container 10 further includes the heat conductive fins 13b. The heat conductive fin 13b is formed of, for example, a high heat conductive material having a thermal conductivity of 1.0 W / (m · K) or more. The heat conductive fin 13b may be formed of a high heat conductive material having a heat conductivity of 5.0 W / (m · K) or more, and has a high heat conductivity of 10.0 W / (m · K) or more. It may be formed of a material, may be formed of a high thermal conductive material having a thermal conductivity of 50.0 W / (m · K) or more, and may have a thermal conductivity of 100.0 W / (m · K) or more. It may be formed of a high thermal conductive material. The heat conductive fins 13b are made of a metal such as copper or aluminum. The heat conductive fin 13b may be formed of the same material as the container 10, or may be formed of a material different from that of the container 10.

The heat conductive fin 13b may have the shape of a plate or the shape of a rod. The heat conductive fin 13b is provided on the first inner wall surface 11b. The heat conductive fin 13b is connected to the first wall 11 (first inner wall surface 11b). The heat conductive fin 13b may be separated from the second wall 12 (second inner wall surface 12b). In the first plan view of the first outer wall surface 11a, the heat conductive fins 13b may overlap with the heating element 3. In the first plan view of the first outer wall surface 11a, the heat conductive fin 13b may be surrounded by the outer shape of the heating element 3.

The heating unit 20 is provided on the heat conductive fin 13b. The bubble generation unit 23 is provided on the heating unit 20. The heat radiating member 18 is attached directly to the second outer wall surface 12a or via the heat transfer member 30e (see FIG. 7).

The effect of the cooling device 1m of the present embodiment has the following effects in addition to the effect of the cooling device 1 of the first embodiment.

In the cooling device 1 m of the present embodiment, the container 10 includes a first wall 11, a second wall 12 facing the first wall 11, and a heat conductive fin 13b. The first wall 11 includes a first inner wall surface 11b that comes into contact with the liquid 17 and a first outer wall surface 11a that is opposite to the first inner wall surface 11b. The second wall 12 includes a second inner wall surface 12b that is in contact with the liquid 17 and faces the first inner wall surface 11b, and a second outer wall surface 12a that is opposite to the second inner wall surface 12b. The first outer wall surface 11a includes a mounting surface 11c. The heat conductive fin 13b is provided on the first inner wall surface 11b. The first heating unit (heating unit 20) is provided on the heat conductive fin 13b. The first bubble generation unit (bubble generation unit 23) is provided on the first heating unit. The heat radiating member 18 is attached directly to the second outer wall surface 12a or via the heat transfer member 30e (see FIG. 7).

Therefore, the cooling device 1 m has a more compact size and higher reliability, and the power consumption of the cooling device 1 m can be reduced.

In the cooling device 1 m of the present embodiment, the heat conductive fins 13b overlap the heating element 3 in the first plan view of the first outer wall surface 11a. Therefore, the first bubble generating section (bubble generating section 23) is heated by the heating element 3 in addition to the first heating section (heating section 20). The energy applied to the first heating section to generate the first bubble (bubble 25) and the first marangoni convection (marangoni convection 26) can be reduced. The power consumption of the cooling device 1 m can be further reduced.

Embodiment 7.
The cooling device 1n of the seventh embodiment will be described with reference to FIG. The cooling device 1n of the present embodiment has the same configuration as the cooling device 1 of the first embodiment, but is different from the cooling device 1 of the first embodiment mainly in the following points.

In the cooling device 1n, the bubble generation unit 23 is provided on the second inner wall surface 12b. The heating unit 20 is provided on the second outer wall surface 12a. The heat radiating member 18 is attached directly to the second outer wall surface 12a or via the heat transfer member 30e (see FIG. 7).

The cooling device 1n further includes a low heat conductive layer 28. The low heat conductive layer 28 is provided between the heating unit 20 and the heat radiating member 18. The low thermal conductivity layer 28 has a lower thermal conductivity than the second wall 12 and the heat dissipation member 18. The low heat conductive layer 28 is, for example, an air layer or a heat insulating layer. The low heat conductive layer 28 reduces the amount of heat dissipated from the heating unit 20 to the heat radiating member 18. In the second plan view of the second outer wall surface 12a, the heating portion 20 overlaps the heat radiating member 18. In the second plan view of the second outer wall surface 12a, the bubble generating portion 23 overlaps the heat radiating member 18. Specifically, in the second plan view of the second outer wall surface 12a, the bubble generating portion 23 is surrounded by the outer shape of the heat radiating member 18. In the second plan view of the second outer wall surface 12a, the heating unit 20 is surrounded by the outer shape of the heat radiating member 18.

The effect of the cooling device 1n of the present embodiment has the following effects in addition to the effect of the cooling device 1 of the first embodiment.

In the cooling device 1n of the present embodiment, the container 10 includes a first wall 11 and a second wall 12 facing the first wall 11. The first wall 11 includes a first inner wall surface 11b that comes into contact with the liquid 17 and a first outer wall surface 11a that is opposite to the first inner wall surface 11b. The second wall 12 includes a second inner wall surface 12b that is in contact with the liquid 17 and faces the first inner wall surface 11b, and a second outer wall surface 12a that is opposite to the second inner wall surface 12b. The first outer wall surface 11a includes a mounting surface 11c. The first bubble generation unit (bubble generation unit 23) is provided on the second inner wall surface 12b. The first heating unit (heating unit 20) is provided on the second outer wall surface 12a. The heat radiating member 18 is attached directly to the second outer wall surface 12a or via the heat transfer member 30e (see FIG. 7).

The first bubble generating section (bubble generating section 23) is provided on the second inner wall surface 12b of the second wall 12 to which the heat radiating member 18 is attached directly or via the heat transfer member 30e (see FIG. 7). ing. The liquid 17 proximal to the first bubble generator and around the first bubble (bubble 25) is further cooled by the second wall 12 and the heat dissipation member 18. Increased difference between the temperature of the liquid 17 proximal to the first bubble generator and around the first bubble and the temperature of the liquid 17 distal to the first bubble generator and around the first bubble do. A stronger first Marangoni convection (Marangoni convection 26) is generated in the liquid 17. Due to the stronger first Marangoni convection, a faster flow 27 of the liquid 17 is generated. The liquid 17 is agitated more vigorously. The liquid 17 that circulates in the container 10 at high speed and is agitated in the container 10 has a high ability to spread the heat generated by the heating element 3 and has a large heat transfer coefficient. The cooling device 1n has a higher cooling capacity and can further cool the heat generated by the heating element 3.

The cooling device 1n of the present embodiment is provided between the first heating unit (heating unit 20) and the heat radiating member 18, and has a lower thermal conductivity than the second wall 12 and the heat radiating member 18. A conductive layer 28 is further provided. In the second plan view of the second outer wall surface 12a, the first heating portion overlaps the heat radiating member 18. In the low thermal conductive layer 28, the first bubble generating section (bubble generating section 23) is heated not only by the first heating section but also by the heating element 3.

The low heat conductive layer 28 reduces the amount of heat dissipated from the first heating unit (heating unit 20) to the heat radiating member 18. The energy applied to the first heating section to generate the first bubble (bubble 25) and the first marangoni convection (marangoni convection 26) can be reduced. The power consumption of the cooling device 1n can be further reduced.

Embodiment 8.
The cooling device 1p of the eighth embodiment will be described with reference to FIG. The cooling device 1p of the present embodiment has the same configuration as the cooling device 1 of the first embodiment, but is different from the cooling device 1 of the first embodiment mainly in the following points.

In the cooling device 1p, the heating unit 20 is provided on the second inner wall surface 12b. The bubble generation unit 23 is provided on the heating unit 20. The heat radiating member 18 is attached directly to the second outer wall surface 12a or via the heat transfer member 30e (see FIG. 7).

The second wall 12 includes the second wall base member 12d and the low heat conductive wall portion 12f. The low thermal conductivity wall portion 12f has a lower thermal conductivity than the second wall base member 12d. For example, when the second wall base member 12d is made of aluminum, the low heat conductive wall portion 12f is made of stainless steel, titanium or resin. The low heat conductive wall portion 12f is provided between the heating portion 20 and the heat radiating member 18. The low heat conductive wall portion 12f may come into contact with the heating portion 20 and the heat radiating member 18. The heating unit 20 may be provided on the low heat conduction wall portion 12f. In the second plan view of the second outer wall surface 12a, the heating portion 20 overlaps the heat radiating member 18.

The effect of the cooling device 1p of the present embodiment has the following effects in addition to the effect of the cooling device 1 of the first embodiment.

In the cooling device 1p of the present embodiment, the container 10 includes a first wall 11 and a second wall 12 facing the first wall 11. The first wall 11 includes a first inner wall surface 11b that comes into contact with the liquid 17 and a first outer wall surface 11a that is opposite to the first inner wall surface 11b. The second wall 12 includes a second inner wall surface 12b that is in contact with the liquid 17 and faces the first inner wall surface 11b, and a second outer wall surface 12a that is opposite to the second inner wall surface 12b. The first outer wall surface 11a includes a mounting surface 11c. The first heating unit (heating unit 20) is provided on the second inner wall surface 12b. The first bubble generation unit (bubble generation unit 23) is provided on the first heating unit. The heat radiating member 18 is attached directly to the second outer wall surface 12a or via the heat transfer member 30e (see FIG. 7).

Therefore, like the cooling device 1p of the seventh embodiment, the cooling device 1p has a higher cooling capacity and can further cool the heat generated by the heating element 3.

In the cooling device 1p of the present embodiment, the second wall 12 includes a second wall base member 12d and a low thermal conductivity wall portion 12f having a thermal conductivity lower than that of the second wall base member 12d. The low heat conduction wall portion 12f is provided between the first heating portion (heating portion 20) and the heat radiating member 18. In the second plan view of the second outer wall surface 12a, the first heating portion overlaps the heat radiating member 18.

The low heat conduction wall portion 12f reduces the amount of heat dissipated from the first heating portion (heating portion 20) to the heat radiating member 18. The energy applied to the first heating section to generate the first bubble (bubble 25) and the first marangoni convection (marangoni convection 26) can be reduced. The power consumption of the cooling device 1p can be further reduced.

Embodiment 9.
The cooling device 1q of the ninth embodiment will be described with reference to FIGS. 17 and 18. The cooling device 1q of the present embodiment has the same configuration as the cooling device 1 of the first embodiment, but is different from the cooling device 1 of the first embodiment mainly in the following points.

The cooling device 1q further includes a temperature sensor 33 and a controller 35.
The temperature sensor 33 is attached to the heating element 3 and directly measures the first temperature of the heating element 3. The temperature sensor 33 is, for example, a thermistor. The temperature sensor 33 may be a radiation thermometer located away from the heating element 3. The first temperature of the heating element 3 may be directly measured by using a radiation thermometer. The temperature sensor 33 is electrically connected to the controller 35. The temperature sensor 33 outputs a signal corresponding to the first temperature of the heating element 3 to the controller 35.

The controller 35 is, for example, a semiconductor processor. The controller 35 adjusts the second temperature of the heating unit 20 based on the output signal of the temperature sensor 33. For example, the cooling device 1q includes a current source 34, and the heating unit 20 is a microheater. The controller 35 is electrically connected to the current source 34. The current source 34 is electrically connected to the heating unit 20. The controller 35 controls the current supplied from the current source 34 to the heating unit 20 based on the output signal of the temperature sensor 33. In this way, the controller 35 adjusts the second temperature of the heating unit 20 based on the output signal of the temperature sensor 33.

Specifically, when the temperature of the heating element 3 rises beyond the appropriate operating temperature range of the heating element 3, the intensity of the output signal from the temperature sensor 33 becomes larger than the threshold value. When the controller 35 determines that the intensity of the output signal from the temperature sensor 33 is larger than the threshold value, the controller 35 supplies a current from the current source 34 to the heating unit 20. The second temperature of the heating unit 20 rises, and the bubble generation unit 23 is heated. Bubbles 25 are generated in the bubble generation unit 23. Marangoni convection 26 is generated in the liquid 17 around the bubbles 25. The Marangoni convection 26 creates a flow 27 of the liquid 17. The heat generated by the heating element 3 is transferred to the heat radiating member 18 through the container 10 and the liquid 17. In this way, the heating element 3 is cooled.

When the temperature of the heating element 3 is within the proper operating temperature range of the heating element 3, the intensity of the output signal from the temperature sensor 33 becomes equal to or less than the threshold value. When the controller 35 determines that the intensity of the output signal from the temperature sensor 33 is equal to or less than the threshold value, the controller 35 stops the supply of current from the current source 34 to the heating unit 20. The second temperature of the heating unit 20 decreases, and the temperature of the bubble generation unit 23 also decreases. Bubbles 25 disappear. The Marangoni convection 26 disappears and the flow 27 of the liquid 17 decreases. Therefore, it is prevented that the heating element 3 is excessively cooled. In this way, the cooling device 1q can keep the temperature of the heating element 3 within the proper operating temperature range of the heating element 3.

_{As shown in the simulation result (see FIG. 18) of the thermal resistance R 2} of the cooling device 1q of the cooling device 1q of the present embodiment, the thermal resistance per unit area when the bubble 25 is on the bubble generating portion 23. R ₂ is smaller than _{the thermal resistance R 2} per unit area when there are no bubbles 25 on the bubble generating portion 23. Therefore, the cooling capacity of the cooling device 1q can be adjusted by adjusting the second temperature of the heating unit 20 based on the output signal of the temperature sensor 33. The thermal resistance R ₂ is per unit area of the cooling device 1q between the first inner wall surface 11b of the first wall 11 including the mounting surface 11c and the second inner wall surface 12b of the second wall 12 to which the heat radiating member 18 is mounted. Means the thermal resistance of.

Further, when the bubble 25 is on the bubble generating portion 23, the thermal resistance R ₂ per unit area hardly increases even if the thickness t of the flow path increases. On the other hand, when the bubble 25 is not on the bubble generating portion 23 and the thickness t of the flow path increases, the thermal resistance R ₂ per unit area increases significantly. The reason is as follows.

When the bubble 25 is on the bubble generating portion 23, the marangoni convection 26 is generated in the liquid 17 around the bubble 25. Due to the Marangoni convection 26, the liquid 17 circulates in the container 10 at high speed and is agitated in the container 10. The liquid 17 that circulates in the container 10 at high speed and is agitated in the container 10 has a high ability to spread the heat generated by the heating element 3 and has a large heat transfer coefficient. Therefore, when the bubble 25 is on the bubble generating portion 23, the thermal resistance R ₂ per unit area hardly increases even if the thickness t of the flow path increases. The thickness t of the flow path is the distance between the first inner wall surface 11b and the second inner wall surface 12b. As shown in FIG. 18, the larger the thickness t of the flow path, the wider the cooling capacity of the cooling device 1q can be controlled.

The temperature sensor 33 may indirectly measure the first temperature of the heating element 3 as in the cooling device 1r of the first modification of the present embodiment shown in FIG. In one example, as shown in FIG. 19, the temperature sensor 33 is attached to the heat radiating member 18 and may measure the temperature of the heat radiating member 18. The higher the first temperature of the heating element 3, the higher the temperature of the heat radiating member 18. By measuring the temperature of the heat radiating member 18 by the temperature sensor 33, the temperature sensor 33 can indirectly measure the first temperature of the heating element 3. In another example, the temperature sensor 33 is attached to the container 10 and may measure the temperature of the container 10. The higher the first temperature of the heating element 3, the higher the temperature of the container 10. By measuring the temperature of the container 10 by the temperature sensor 33, the temperature sensor 33 can indirectly measure the first temperature of the heating element 3.

In the cooling device 1s of the second modification of the present embodiment shown in FIG. 20, the heating unit 20 is a semiconductor laser as in the cooling device 1b of the first modification of the first embodiment shown in FIG. It may be a light absorption film irradiated with light from such a light source 21. The controller 35 is electrically connected to the light source 21. The controller 35 controls the power of the light output from the light source 21 based on the output signal of the temperature sensor 33. In this way, the controller 35 adjusts the second temperature of the heating unit 20 based on the output signal of the temperature sensor 33.

Specifically, when the controller 35 determines that the intensity of the output signal from the temperature sensor 33 is larger than the threshold value, the controller 35 increases the power of the light output from the light source 21. The temperature of the heating unit 20 irradiated with the light from the light source 21 rises, and the bubble generation unit 23 is heated. Bubbles 25 are generated in the bubble generation unit 23. Marangoni convection 26 is generated in the liquid 17 around the bubbles 25. The Marangoni convection 26 creates a flow 27 of the liquid 17. The heat generated by the heating element 3 is transferred to the heat radiating member 18 through the container 10 and the liquid 17. In this way, the heating element 3 is cooled.

When the controller 35 determines that the intensity of the output signal from the temperature sensor 33 is equal to or less than the threshold value, the controller 35 stops the output of light from the light source 21. The temperature of the heating unit 20 decreases, and the temperature of the bubble generation unit 23 also decreases. Bubbles 25 disappear. The Marangoni convection 26 disappears and the flow 27 of the liquid 17 decreases. Therefore, it is prevented that the heating element 3 is excessively cooled. In this way, the cooling device 1s can keep the temperature of the heating element 3 within the proper operating temperature range of the heating element 3.

The effects of the cooling devices 1q, 1r, 1s of the present embodiment have the following effects in addition to the effects of the cooling device 1 of the first embodiment.

In the cooling devices 1q, 1r, 1s of the present embodiment, the temperature sensor 33 that directly or indirectly measures the first temperature of the heating element 3 and the first heating unit (heating) based on the output signal of the temperature sensor 33. A controller 35 for adjusting the second temperature of the unit 20) is further provided. Therefore, the cooling devices 1q, 1r, 1s can appropriately cool the heating element 3 according to the amount of heat generated by the heating element 3 or the ambient temperature of the heating element 3. The cooling devices 1q, 1r, 1s can keep the temperature of the heating element 3 within the proper operating temperature range of the heating element 3.

Embodiment 10.
The cooling device 1t of the tenth embodiment will be described with reference to FIG. 21. The cooling device 1t of the present embodiment has the same configuration as the cooling device 1 of the first embodiment, but is different from the cooling device 1 of the first embodiment mainly in the following points.

The cooling device 1t of the present embodiment further includes a heating unit 20t and a bubble generation unit 23t.

The heating unit 20t is configured in the same manner as the heating unit 20. For example, the heating unit 20t is supported by the container 10. In one example, the heating unit 20t is provided on the second outer wall surface 12a. The heating unit 20t is, for example, a micro heater or a thin film heater. The heating unit 20t is electrically connected to the current source 34. By supplying a current from the current source 34 to the heating unit 20t, heat is generated in the heating unit 20t. This heat is conducted to the bubble generating portion 23t through the container 10 (first wall 11). In this way, the heating unit 20t heats the bubble generation unit 23t.

The area of the heating unit 20t has an area of 1.0 mm ² or less. The area of the heating portion 20t may be in 0.5 mm ² or less, may also be 0.2 mm ² or less, and may be 0.2 mm ² or less. In the present embodiment, the area of the heating portion 20t is the area of the heating portion 20t in the plan view of the first outer wall surface 11a. The area of the heating unit 20t is smaller than the area of the heating element 3, and the thickness of the heating unit 20t is smaller than the thickness of the heating element 3. The area of the heating portion 20t is smaller than the area of the mounting surface 11c.

The amount of heat generated by the heating unit 20t can be ignored with respect to the amount of heat generated by the heating element 3. The amount of heat generated by the heating unit 20t is, for example, less than one-twentieth of the amount of heat generated by the heating element 3. The amount of heat generated by the heating unit 20t may be one-hundredth or less of the amount of heat generated by the heating element 3. The amount of heat generated by the heating unit 20t is, for example, 50 mW or less. The amount of heat generated by the heating unit 20t may be 30 mW or less. The amount of heat generated by the heating element 3 is, for example, 1 W or more. The amount of heat generated by the heating element 3 may be 100 W or more.

The heating unit 20t is separated from the heating unit 20. The distance between the heating unit 20 and the heating unit 20t is, for example, 10 mm or less. The distance between the heating unit 20 and the heating unit 20t may be 5 mm or less, or may be 3 mm or less.

The bubble generation unit 23t is configured in the same manner as the bubble generation unit 23. For example, the bubble generation unit 23t is supported by the container 10. In one example, the bubble generating portion 23t is provided on the first inner wall surface 11b. The bubble generation unit 23t is in contact with the liquid 17. The bubble generation unit 23t is, for example, a bubble generation film. The bubble generating portion 23t is made of, for example, copper or aluminum. The bubble generating portion 23t may be formed of a material different from that of the container 10, or may be formed of the same material as the container 10.

The area of the bubble generating portion 23t (the area of the bubble fixing surface of the bubble generating portion 23t) has an area of 1.0 mm ² or less. The area of the bubble generating portion 23t may be 0.5 mm ² or less, 0.2 mm ² or less, ^{or 0.1 mm 2} or less. In the present embodiment, the area of the bubble generating portion 23t is the area of the bubble generating portion 23t in the plan view of the first inner wall surface 11b. The area of the bubble generating section 23t (the bubble fixing surface of the bubble generating section 23t) is smaller than the area of the heating element 3, and the thickness of the bubble generating section 23t is smaller than the thickness of the heating element 3. The area of the bubble generating portion 23t is smaller than the area of the mounting surface 11c.

The bubble generation unit 23t is heated by the heating unit 20t to generate bubbles 25t in the liquid 17. The bubble 25t is fixed to the bubble generation unit 23t. The bubble 25t is a minute bubble. The diameter of the bubble 25t is, for example, 100 μm or less. The diameter of the bubble 25t is, for example, 10 μm or more. Marangoni convection 26t is generated in the liquid 17 around the bubble 25t.

The bubble generation unit 23t is separated from the bubble generation unit 23. The distance between the bubble generating section 23 and the bubble generating section 23t is, for example, 10 mm or less. The distance between the bubble generating section 23 and the bubble generating section 23t may be 5 mm or less, or may be 3 mm or less. Therefore, the bubble generation unit 23 and the bubble generation unit 23t can cooperate to generate the flow 27 of the liquid 17 and agitate the liquid 17.

The cooling device 1t of the present embodiment further includes a temperature sensor 33 and a controller 35, similarly to the cooling device 1q of the ninth embodiment.

The temperature sensor 33 directly measures the first temperature of the heating element 3 in the same manner as the temperature sensor 33 of the ninth embodiment. The temperature sensor 33 may indirectly measure the first temperature of the heating element 3 in the same manner as the temperature sensor 33 of the first modification of the ninth embodiment. The current source 34 is electrically connected to the heating unit 20 and the heating unit 20t. The controller 35 adjusts the second temperature of the heating unit 20 and the third temperature of the heating unit 20t based on the output signal of the temperature sensor 33.

Specifically, when the temperature of the heating element 3 rises beyond the appropriate operating temperature range of the heating element 3, the intensity of the output signal from the temperature sensor 33 becomes larger than the threshold value. When the controller 35 determines that the intensity of the output signal from the temperature sensor 33 is larger than the threshold value, the controller 35 supplies a current from the current source 34 to the heating unit 20 and the heating unit 20t. The second temperature of the heating unit 20 rises, and the bubble generation unit 23 is heated. The third temperature of the heating unit 20t rises, and the bubble generation unit 23t is heated. Bubbles 25 are generated in the bubble generation unit 23, and bubbles 25t are generated in the bubble generation unit 23t. Marangoni convection 26 is generated in the liquid 17 around the bubbles 25. Marangoni convection 26t is generated in the liquid 17 around the bubble 25t. The Marangoni convection 26 and the Marangoni convection 26t give rise to the flow 27 of the liquid 17. The heat generated by the heating element 3 is transferred to the heat radiating member 18 through the container 10 and the liquid 17. In this way, the heating element 3 is cooled.

When the temperature of the heating element 3 is within the proper operating temperature range of the heating element 3, the intensity of the output signal from the temperature sensor 33 becomes equal to or less than the threshold value. When the controller 35 determines that the intensity of the output signal from the temperature sensor 33 is equal to or less than the threshold value, the controller 35 stops the supply of current from the current source 34 to the heating unit 20 and the heating unit 20t. The second temperature of the heating unit 20 decreases, and the temperature of the bubble generation unit 23 also decreases. The third temperature of the heating unit 20t decreases, and the temperature of the bubble generation unit 23t also decreases. The bubble 25 and the bubble 25t disappear. The Marangoni convection 26 and the Marangoni convection 26t disappear, and the flow 27 of the liquid 17 decreases. Therefore, it is prevented that the heating element 3 is excessively cooled. In this way, the cooling device 1t can keep the temperature of the heating element 3 within the proper operating temperature range of the heating element 3.

With reference to FIG. 22, the cooling device 1u of the modified example of the present embodiment will be described. In the cooling device 1u, the second temperature of the heating unit 20 and the third temperature of the heating unit 20t can be adjusted independently of each other.

Specifically, the cooling device 1u includes a current source 34t in addition to the current source 34. The controller 35 is electrically connected to the current source 34 and the current source 34t. The current source 34 is electrically connected to the heating unit 20. The current source 34t is electrically connected to the heating unit 20t. The controller 35 controls the current supplied from the current source 34 to the heating unit 20 and the current supplied from the current source 34t to the heating unit 20t based on the output signal of the temperature sensor 33. In this way, the controller 35 can adjust the second temperature of the heating unit 20 and the third temperature of the heating unit 20t independently of each other based on the output signal of the temperature sensor 33.

Therefore, the generation of the bubble 25 and the generation of the bubble 25t can be controlled independently. The Marangoni convection 26 and the Marangoni convection 26t can be controlled independently. A variety of flows 27 can be created in the liquid 17. Depending on the type of heating element 3 or the ambient temperature of the heating element 3, the heating element 3 can be cooled more efficiently or more appropriately.

For example, the controller 35 may alternately supply an electric current to the heating unit 20 and the heating unit 20t to alternately generate the bubbles 25 and the bubbles 25t. Since the Marangoni convection 26 and the Marangoni convection 26t are alternately generated, the liquid 17 is agitated more violently. The heat transfer capacity of the liquid 17 is increased. The heat generated by the heating element 3 is efficiently cooled by the container 10 (for example, the first wall 11 of the container 10) and the liquid 17.

In the cooling devices 1t and 1u of the present embodiment and its modifications, the number of bubble generating units 23 and 23t is two, and the number of heating units 20 and 20t is two, but the number of bubble generating units 23 is two. , 23t may be three or more, and the heating portions 20, 20t may be three or more.

The effects of the cooling devices 1t and 1u of the present embodiment have the following effects in addition to the effects of the cooling device 1 of the first embodiment.

The cooling devices 1t and 1u of the present embodiment further include a second bubble generating section (bubble generating section 23t) and a second heating section (heating section 20t). The second bubble generating portion is supported by the container 10 and is in contact with the liquid 17. The second heating unit heats the second bubble generation unit. The second bubble generation unit generates a second bubble (bubble 25t) fixed to the second bubble generation unit in the liquid 17. A second Marangoni convection (Marangoni convection 26t) is generated in the liquid 17 around the second bubble. Therefore, the flow 27 of the liquid 17 can be made faster. The liquid 17 can be agitated more violently. The cooling devices 1t and 1u can cool the heating element 3 more efficiently.

In the cooling devices 1t and 1u of the present embodiment, the temperature sensor 33 that directly or indirectly measures the first temperature of the heating element 3 and the first heating unit (heating unit 20) based on the output signal of the temperature sensor 33. ), And a controller 35 for adjusting the second temperature of the second heating unit (heating unit 20t). Therefore, the heating element 3 can be cooled more efficiently or more appropriately depending on the type of the heating element 3 or the ambient temperature of the heating element 3. The cooling devices 1t and 1u can keep the temperature of the heating element 3 within the proper operating temperature range of the heating element 3.

In the cooling device 1u of the present embodiment, the second temperature of the first heating unit (heating unit 20) and the third temperature of the second heating unit (heating unit 20t) can be adjusted independently of each other. Therefore, various flows 27 can be created in the liquid 17. The cooling device 1u can cool the heating element 3 more efficiently or more appropriately depending on the type of the heating element 3 or the ambient temperature of the heating element 3. The cooling device 1u can keep the temperature of the heating element 3 within the proper operating temperature range of the heating element 3.

It should be considered that the first to tenth embodiments disclosed this time and their variations are exemplary in all respects and not restrictive. As long as there is no contradiction, at least two of the first to tenth embodiments disclosed this time and variations thereof may be combined. For example, in the first embodiment and the third embodiment to the tenth embodiment and the modified examples thereof, as in the second embodiment, the concave portion 24 or the rough surface is formed on the bubble fixing surface of the first bubble generating portion. May be good. The scope of this disclosure is set forth by the claims rather than the description above and is intended to include all modifications within the meaning and scope of the claims.

1,1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1m, 1n, 1p, 1q, 1r, 1s, 1t, 1u cooling device, 3 heating element, 3p center line, 10 container , 11 1st wall, 11a 1st outer wall surface, 11b 1st inner wall surface, 11c mounting surface, 11d 1st wall base member, 11e high heat conduction wall part, 11f, 12f low heat conduction wall part, 11p, 12p intersection, 12th 2 wall, 12a 2nd outer wall surface, 12b 2nd inner wall surface, 12d 2nd wall base member, 12q point, 13 3rd wall, 13b heat conductive fin, 17 liquid, 18 heat dissipation member, 20, 20t heating part, 21 light source , 23, 23t bubble generator, 24 recess, 25, 25t bubble, 26, 26t marangoni convection, 27 flow, 28 low heat conductive layer, 30 heat conductive member, 30e heat transfer member, 33 temperature sensor, 34, 34t current source, 35 controller.

Claims (17)

1. A cooling device that cools a heating element, and the cooling device is
   A container containing a liquid and a container
   With a heat dissipation member attached directly to the container or via a heat transfer member,
   A first bubble generator that is supported by the container and is in contact with the liquid,
   A first heating unit for heating the first bubble generation unit is provided.
   The container comprises a mounting surface to which the heating element is attached, either directly or via a heat conductive member.
   The first bubble generation unit generates first bubbles fixed to the first bubble generation unit in the liquid.
   A cooling device in which a first Marangoni convection is generated in the liquid around the first bubble.
2. The cooling device according to claim 1, wherein a rough surface or a recess that is coarser than the surface of the support member of the container that supports the first bubble generating portion is formed on the bubble fixing surface of the first bubble generating portion.
3. The container includes a first wall and a second wall facing the first wall.
   The first wall includes a first inner wall surface that comes into contact with the liquid and a first outer wall surface that is opposite to the first inner wall surface.
   The second wall includes a second inner wall surface that is in contact with the liquid and faces the first inner wall surface, and a second outer wall surface that is opposite to the second inner wall surface.
   The first outer wall surface includes the mounting surface.
   The first bubble generation unit is provided on the first inner wall surface.
   The first heating unit is provided on the first outer wall surface, and is provided on the first outer wall surface.
   The cooling device according to claim 1 or 2, wherein the heat radiating member is attached directly to the second outer wall surface or via the heat transfer member.
4. The first wall includes a first wall base member and a high thermal conductivity wall portion having a higher thermal conductivity than the first wall base member.
   The cooling device according to claim 3, wherein the high heat conduction wall portion is provided between the first bubble generation section and the first heating section.
5. The first wall further includes a low thermal conductivity wall portion having a lower thermal conductivity than the first wall base member.
   The cooling device according to claim 4, wherein the low thermal conductive wall portion is provided between the first wall base member and the high thermal conductive wall portion.
6. The container includes a first wall and a second wall facing the first wall.
   The first wall includes a first inner wall surface that comes into contact with the liquid and a first outer wall surface that is opposite to the first inner wall surface.
   The second wall includes a second inner wall surface that is in contact with the liquid and faces the first inner wall surface, and a second outer wall surface that is opposite to the second inner wall surface.
   The first outer wall surface includes the mounting surface.
   The first heating unit is provided on the first inner wall surface, and is provided on the first inner wall surface.
   The first bubble generation unit is provided on the first heating unit, and is provided on the first heating unit.
   The cooling device according to claim 1 or 2, wherein the heat radiating member is attached directly to the second outer wall surface or via the heat transfer member.
7. The cooling device according to any one of claims 3 to 6, wherein the first bubble generating unit overlaps the heating element in a first plan view of the first outer wall surface.
8. The container includes a first wall, a second wall facing the first wall, and heat conductive fins.
   The first wall includes a first inner wall surface that comes into contact with the liquid and a first outer wall surface that is opposite to the first inner wall surface.
   The second wall includes a second inner wall surface that is in contact with the liquid and faces the first inner wall surface, and a second outer wall surface that is opposite to the second inner wall surface.
   The first outer wall surface includes the mounting surface.
   The heat conductive fin is provided on the first inner wall surface, and the heat conductive fin is provided on the first inner wall surface.
   The first heating portion is provided on the heat conductive fin, and is provided on the heat conductive fin.
   The first bubble generation unit is provided on the first heating unit, and is provided on the first heating unit.
   The cooling device according to claim 1 or 2, wherein the heat radiating member is attached directly to the second outer wall surface or via the heat transfer member.
9. The cooling device according to claim 8, wherein the heat conductive fins overlap the heating element in a first plan view of the first outer wall surface.
10. The container includes a first wall and a second wall facing the first wall.
    The first wall includes a first inner wall surface that comes into contact with the liquid and a first outer wall surface that is opposite to the first inner wall surface.
    The second wall includes a second inner wall surface that is in contact with the liquid and faces the first inner wall surface, and a second outer wall surface that is opposite to the second inner wall surface.
    The first outer wall surface includes the mounting surface.
    The first bubble generation unit is provided on the second inner wall surface.
    The first heating unit is provided on the second outer wall surface, and is provided on the second outer wall surface.
    The cooling device according to claim 1 or 2, wherein the heat radiating member is attached directly to the second outer wall surface or via the heat transfer member.
11. A low thermal conductive layer provided between the first heating portion and the heat radiating member and having a lower thermal conductivity than the second wall and the heat radiating member is further provided.
    The cooling device according to claim 10, wherein the first heating unit overlaps the heat radiating member in a second plan view of the second outer wall surface.
12. The container includes a first wall and a second wall facing the first wall.
    The first wall includes a first inner wall surface that comes into contact with the liquid and a first outer wall surface that is opposite to the first inner wall surface.
    The second wall includes a second inner wall surface that is in contact with the liquid and faces the first inner wall surface, and a second outer wall surface that is opposite to the second inner wall surface.
    The first outer wall surface includes the mounting surface.
    The first heating unit is provided on the second inner wall surface, and is provided on the second inner wall surface.
    The first bubble generation unit is provided on the first heating unit, and is provided on the first heating unit.
    The cooling device according to claim 1 or 2, wherein the heat radiating member is attached directly to the second outer wall surface or via the heat transfer member.
13. The second wall includes a second wall base member and a low thermal conductivity wall portion having a lower thermal conductivity than the second wall base member.
    The low heat conduction wall portion is provided between the first heating portion and the heat dissipation member.
    The cooling device according to claim 12, wherein in the second plan view of the second outer wall surface, the first heating unit overlaps the heat radiating member.
14. A temperature sensor that directly or indirectly measures the first temperature of the heating element, and
    The cooling device according to any one of claims 1 to 13, further comprising a controller for adjusting the second temperature of the first heating unit based on the output signal of the temperature sensor.
15. A second bubble generator that is supported by the container and is in contact with the liquid,
    Further provided with a second heating unit for heating the second bubble generation unit, the second heating unit is further provided.
    The second bubble generating section generates a second bubble fixed to the second bubble generating section in the liquid.
    The cooling device according to any one of claims 1 to 13, wherein a second marangoni convection is generated in the liquid around the second bubble.
16. A temperature sensor that directly or indirectly measures the first temperature of the heating element, and
    The cooling device according to claim 15, further comprising a controller for adjusting the second temperature of the first heating unit and the third temperature of the second heating unit based on the output signal of the temperature sensor.
17. The cooling device according to claim 16, wherein the second temperature of the first heating unit and the third temperature of the second heating unit can be adjusted independently of each other.

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