Cooling device and heating element comprising same

Abstract

A cooling device (1) comprises a housing (3), a heater (17), and a heater power supply (27). The heater (17) includes a first electrode (19), a second electrode (21), and a narrow part (23). A coolant (5) accommodated in a passage (7) in the housing (3) produces bubbles at the narrow part (23) and thereby flows in a loop between a heat absorption part (9) and a heat dissipation part (11). The heater (17), which is a current path along which current flows due to power supplied from the heater power supply (27), has a path cross-sectional area (CS). The path cross-sectional area (CS) at the narrow part (23) is a narrow cross-sectional area (CS3). The narrow part (23) is formed such that the narrow cross-sectional area (CS3) becomes smaller along the X-axis direction.

Description

Cooling device and heating element equipped with same

[0001] The present disclosure relates to a cooling device and a heating element equipped with the same.

[0002] In recent years, semiconductor laser devices with high output power ranging from several watts to approximately 100 watts have been developed. A semiconductor laser device has a stack structure in which multiple semiconductor laser arrays are stacked. In a semiconductor laser array, approximately half of the power supplied becomes heat. A heat sink is used to dissipate this heat.

[0003] In the case of a semiconductor laser array having a stacked structure, a heat sink is inserted between each of the stacked semiconductor laser arrays. In a semiconductor laser device, cooling is performed by connecting a pipe to the semiconductor laser array having the stacked structure and circulating a coolant through the pipe (Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2005-268446

[0005] In the semiconductor laser device described above, a pump drive source for circulating a coolant is required to cool the semiconductor laser array having a stack structure. The pump drive source is said to consume a relatively large amount of power. Therefore, from the viewpoint of energy conservation, it is desired to reduce the power consumption required for cooling the semiconductor laser device, etc.

[0006] The present disclosure has been made to solve such problems, and one object is to provide a cooling device that reduces power consumption, and another object is to provide a heat generating body equipped with such a cooling device.

[0007] The cooling device according to the present disclosure is a cooling device for cooling a heat-generating body, and includes a housing, a heat absorption portion, a heat dissipation portion, and a heater portion. The housing accommodates a refrigerant. The heat absorption portion is provided in the housing and causes the refrigerant to absorb heat from the heat-generating body. The heat dissipation portion is provided in the housing and causes the refrigerant to dissipate heat absorbed by the refrigerant. The heater portion is disposed within the housing and generates heat by current supplied from a heater power supply. The housing has a flow path through which the refrigerant flows in a circular pattern between the heat absorption portion and the heat dissipation portion. The heater portion includes a first electrode, a second electrode, and a constriction portion. The second electrode is disposed at a distance from the first electrode. The constriction portion is an electrode connecting the first electrode and the second electrode. The heater portion has a path cross-sectional area. The path cross-sectional area of ​​the constriction portion is the constriction cross-sectional area. The constriction portion is formed in a manner such that the constriction cross-sectional area decreases along a first direction.

[0008] A heating element with a cooling device according to the present disclosure is the heating element with the cooling device described above, and further includes a heating element power supply for driving the heating element. The heating element power supply includes a heater power supply.

[0009] In the cooling device according to the present disclosure, the refrigerant contained in the flow path of the housing generates bubbles in the narrowed portion of the heater section, causing the refrigerant to flow in a circular pattern between a heat absorption section that absorbs heat from the heat generating element and a heat dissipation section that dissipates the absorbed heat. The heater section, through which current flows due to power supplied from the heater power supply, has a set path cross-sectional area. The path cross-sectional area of ​​the narrowed portion is the narrowed cross-sectional area. The narrowed portion is formed such that the narrowed cross-sectional area decreases along a first direction. This reduces the power consumption required to cool the heat generating element.

[0010] In the heating element equipped with a cooling device according to the present disclosure, the heat generating power source that drives the heating element includes a heater power source that supplies power to the heater portion, thereby reducing the power consumption required to cool the heating element.

[0011] 6 is a plan view of a cooling device according to a first embodiment. FIG. 7 is a cross-sectional view taken along the line II-II in FIG. 1 in the same embodiment. FIG. 8 is a plan view showing the internal structure of a housing of the cooling device according to the same embodiment. FIG. 9 is a first plan view showing the relative positioning of a heater section and a heat generating element according to the same embodiment. FIG. 10 is a second plan view showing the relative positioning of a heater section and a heat generating element according to the same embodiment. FIG. 11 is a view for explaining the structure of a narrowed portion in the heater section according to the same embodiment. FIG. 12 is a view for explaining the relationship in size between the cross-sectional areas of the paths in the heater section according to the same embodiment. FIG. 13 is a partially enlarged cross-sectional view taken along the line VIII-VIII in FIG. 6 for explaining the flow of refrigerant in a flow path according to the same embodiment. FIG. 14 is a cross-sectional view showing the flow of refrigerant in a flow path in addition to the cross-sectional view shown in FIG. 2 in the same embodiment. FIG. 15 is a cross-sectional view showing the flow of refrigerant in a flow path in addition to the plan view shown in FIG. 3 in the same embodiment. FIG. 16 is a cross-sectional view of a cooling device according to a second embodiment taken along the line II-II in FIG. 1. FIG. 17 is a plan view showing the internal structure of a housing of the cooling device according to the same embodiment. FIG. 18 is a view for explaining the structure of a narrowed portion in the heater section according to the same embodiment. 12 is a plan view showing the flow of refrigerant in the flow path in addition to the plan view shown in FIG. 12. FIG. 13 is a plan view showing the flow of refrigerant in the flow path in addition to the plan view shown in FIG. 11. FIG. 14 is a plan view showing the flow of refrigerant in the flow path in addition to the plan view shown in FIG. 12. FIG. 15 is a plan view showing the structure of a housing of a cooling device for a heating element equipped with a cooling device in accordance with embodiment 3. FIG. 16 is a plan view showing the flow of refrigerant in the flow path in addition to the plan view shown in FIG. 18. FIG. 17 is a plan view showing the flow of refrigerant in the flow path in addition to the plan view shown in FIG. 19.

[0012] Embodiment 1 An example of a cooling device according to embodiment 1 will be described. Note that an XYZ coordinate system will be used as necessary to explain the structure of the cooling device.

[0013] 1, 2, and 3, a cooling device 1 for cooling a heat generating element 31 such as a semiconductor laser device includes a housing 3, a heater unit 17, and a heater power supply 27. A coolant 5 is accommodated in the housing 3. A flow path 7 through which the coolant 5 flows is formed in the housing 3. The housing 3 is made of, for example, metal. The housing 3 is made of, for example, aluminum or copper. The size of the housing 3 is, for example, about 2 cm (X-axis direction) × 2 cm (Y-axis direction) × several hundred μm to several mm (Z-axis direction).

[0014] The heating element 31 is disposed on the surface of the housing 3 with an insulating material (not shown) interposed therebetween. A heating element power supply 33 is electrically connected to the heating element 31. The heating element power supply 33 has a positive electrode 35a and a negative electrode 35b. The positive electrode 35a and the negative electrode 35b are each electrically connected to a corresponding terminal (not shown) of the heating element 31.

[0015] A heat absorption section 9 is provided in a portion (flow path 7a) of the flow path 7 facing the heating element 31 arranged in the housing 3, causing the refrigerant 5 to absorb heat from the heating element 31. A heat dissipation section 11 is provided in a portion of the flow path 7 away from the heat absorption section 9 (flow path 7a), causing the refrigerant 5 to dissipate the heat absorbed by the refrigerant 5. A plurality of fins 13 are arranged at intervals in the heat dissipation section 11. The refrigerant 5 in the housing 3 flows in a circular pattern between the heat absorption section 9 and the heat dissipation section 11 through the flow path 7. Water, for example, is used as the refrigerant 5. In addition to water, alcohol, ketone, glycol ether, or ester, for example, may also be used.

[0016] The heater unit 17 is housed in the flow path 7 through which the refrigerant 5 flows. Here, the heater unit 17 is disposed in a flow path 7a of the flow path 7, facing the heating element 31. The heater unit 17 is disposed in the flow path 7a where the heat absorption unit 9 is located. In this case, the flow path 7a extends in the X-axis direction. The heater unit 17 is housed so as to be electrically insulated from the metal housing 3. The heater unit 17 includes a first electrode 19, a second electrode 21, and a narrowed portion 23. The heater unit 17 is formed by integrating the first electrode 19, the second electrode 21, and the narrowed portion 23. The first electrode 19 and the second electrode 21 are disposed at an interval along the X-axis direction. The narrowed portion 23 is disposed to connect the first electrode 19 and the second electrode 21.

[0017] The heater section 17 has a uniform thickness, which is the length in the Z-axis direction. In other words, the first electrode 19, the second electrode 21, and the narrowed section 23 have the same thickness. The length in the X-axis direction of the narrowed section 23 is shorter than the lengths in the X-axis direction of each of the first electrode 19 and the second electrode 21. The length in the Y-axis direction of the narrowed section 23 is shorter than the lengths in the Y-axis direction of each of the first electrode 19 and the second electrode 21. Therefore, the volume of the narrowed section 23 is smaller than the volumes of each of the first electrode 19 and the second electrode 21.

[0018] 4, the heater section 17 and the heating element 31 are arranged such that a center line TL1 in the X-axis direction of the heater section 17 and a center line TL2 in the X-axis direction of the heating element 31 overlap in a plan view (X-Y plane). Note that the heater section 17 and the heating element 31 do not necessarily need to be arranged such that the center line TL1 and the center line TL2 overlap, and the heater section 17 and the heating element 31 may be arranged such that the center line TL1 is shifted in the X-axis direction with respect to the center line TL2.

[0019] 5, the heater unit 17 and the heat generating element 31 may be disposed such that the center line TL1 is shifted upstream of the coolant flow (positive direction of the X-axis) with respect to the center line TL2. That is, the heater unit 17 may be disposed upstream of the coolant flow with respect to the heat generating element 31. By disposing the heater unit 17 upstream of the coolant flow with respect to the heat generating element 31, a higher cooling effect can be obtained. The coolant flow will be described later.

[0020] A heater power supply 27 that supplies power to the heater unit 17 is electrically connected to the heater unit 17. The heater unit 17 generates heat due to the current supplied from the heater power supply 27. The heater power supply 27 has a positive electrode 29a as a first electrode and a negative electrode 29b as a second electrode. The positive electrode 29a is electrically connected to the first electrode 19. The negative electrode 29b is electrically connected to the second electrode 21. The heater unit 17 serves as a current path through which a current flows due to the power supplied from the heater power supply 27. A path cross-sectional area CS is set in the heater unit 17 that forms the current path in a direction intersecting with the current path. In this case, the path cross-sectional area set in the heater unit 17 is the cross-sectional area of ​​a Y-Z cross section, which is a cross section along the Y-axis direction.

[0021] 6 and 7 , a first electrode cross-sectional area CS1 is set as the path cross-sectional area CS of the first electrode 19. A second electrode cross-sectional area CS2 is set as the path cross-sectional area CS of the second electrode 21. A constriction cross-sectional area CS3 is set as the path cross-sectional area CS of the constriction portion 23.

[0022] The relationship in magnitude of the path cross-sectional area CS will be explained with reference to Fig. 7. The upper part of Fig. 7 shows the three-dimensional structure of the heater section 17, with the Y-Z plane appearing. The middle part of Fig. 7 shows the end face (Y-Z end face) of the first electrode 19 of the heater section 17 to which the narrowed section 23 is connected. The lower part of Fig. 7 shows the end face (Y-Z end face) of the second electrode 21 of the heater section 17 to which the narrowed section 23 is connected.

[0023] As shown in the middle of Fig. 7, the constriction cross-sectional area CS3 (CS3A) is smaller than the first electrode cross-sectional area CS1. As shown in the bottom of Fig. 7, the constriction cross-sectional area CS3 (CS3B) is smaller than the second electrode cross-sectional area CS2. That is, the constriction cross-sectional area CS3 is set to be smaller than both the first electrode cross-sectional area CS1 and the second electrode cross-sectional area CS2.

[0024] The narrowed portion 23 is formed such that the narrowed cross-sectional area CS3 decreases along the X-axis direction. The narrowed portion 23 is formed such that the narrowed cross-sectional area CS3 monotonically decreases along the X-axis direction without having an extreme value. The width WD of the narrowed portion 23 is, for example, a width WDA on the first electrode 19 side of several tens of μm. The width WDB on the second electrode 21 side of the narrowed portion 23 is, for example, about 10 μm.

[0025] In this case, the narrowed cross-sectional area CS3 decreases along the X-axis direction from a narrowed cross-sectional area CS3A (width WDA × thickness) to a narrowed cross-sectional area CS3B (width WDB × thickness). The narrowed portion 23 is formed so that the narrowed cross-sectional area CS3 monotonically decreases without any extreme value from the portion connected to the first electrode 19 to the portion connected to the second electrode 21. The cooling device 1 according to the first embodiment is configured as described above.

[0026] In the cooling device 1 described above, the heat generating element 31 is cooled by the refrigerant 5 flowing in a circular pattern between the heat absorption portion 9 and the heat dissipation portion 11. Microbubbles are generated by heating the narrowed portion 23 of the heater portion 17, causing the refrigerant 5 to flow in a fixed direction. Next, this mechanism will be described.

[0027] Electric power is supplied to the heater section 17 by the heater power supply 27. The narrowing cross-sectional area CS3 is smaller than the first electrode cross-sectional area CS1 and the second electrode cross-sectional area CS2. The temperature of the heater section 17 is inversely proportional to the path cross-sectional area CS. The smaller the path cross-sectional area CS, the higher the temperature. Therefore, the temperature of the narrowing section 23 in the heater section 17 in particular rises. As a result, the refrigerant 5 in contact with the narrowing section 23 vaporizes, generating bubbles 41 (microbubbles). Note that the temperatures of the first electrode 19 and the second electrode 21 are lower than the temperature of the narrowing section 23.

[0028] Here, the cross-sectional area of ​​the narrowed portion 23 is set to decrease in the positive direction of the X-axis. As a result, as shown in Fig. 8, the temperature of the narrowed portion 23 increases in the positive direction of the X-axis. A relatively high temperature region 25a including the highest temperature portion and a relatively low temperature region 25b are formed in the narrowed portion 23. The bubbles 41 are generated in the region 25a including the highest temperature portion in the narrowed portion 23. The bubbles 41 are generated in the portion of the narrowed portion 23 connected to the second electrode 21 (region 25a).

[0029] At this time, the temperature of region 25b in constriction portion 23 located on the negative side of region 25a along the X axis where bubble 41 was generated is higher than the temperature of second electrode 21 located on the positive side of region 25a along the X axis. As a result, the temperature of refrigerant 5 located on the negative side of generated bubble 41 along the X axis is higher than the temperature of refrigerant 5 located on the positive side of bubble 41 along the X axis.

[0030] As a result, a temperature gradient occurs at the interface between the refrigerant 5 and the bubbles 41. Because the surface tension of the refrigerant 5 changes with temperature, when a temperature gradient occurs at the interface between the refrigerant 5 and the bubbles 41, a shear force called a Marangoni force is generated due to the temperature gradient. That is, a shear force is generated when a high-temperature portion of the refrigerant 5 pulls on a low-temperature portion of the refrigerant 5. This shear force causes the refrigerant 5 to flow in the positive direction of the X-axis, as indicated by arrow YA. That is, the refrigerant 5 flows along the flow path 7a extending in the X-axis direction.

[0031] Furthermore, as the temperature of the narrowed portion 23 rises, the bubbles 41 tend to grow. However, if the bubbles 41 become too large, the temperature and pressure inside the bubbles 41 decrease, causing the bubbles 41 to shrink. This repeated change in the volume of the bubbles 41 also causes a flow of the refrigerant 5.

[0032] As heating of the constricted portion 23 progresses, the temperature at the surface of the bubble 41 rises and the Marangoni force increases, but the surface of the bubble 41 is cooled more strongly by the flow of the refrigerant 5. As a result, the bubble 41 does not leave the constricted portion 23, and the temperature gradient at the surface of the bubble 41 and the size of the bubble 41 remain approximately constant on average over time.

[0033] 9 and 10 , in cooling device 1, the generation of bubbles 41 causes refrigerant 5 to flow through flow path 7 as shown by arrow YA. Flow path 7 allows refrigerant 5 to flow in a circular pattern between heat absorption portion 9 and heat radiation portion 11. Heat generated from heating element 31 is absorbed by refrigerant 5 at heat absorption portion 9. The heat absorbed by refrigerant 5 is radiated at heat radiation portion 11. By causing refrigerant 5 to flow in a circular pattern between heat absorption portion 9 and heat radiation portion 11, heating element 31 can be continuously cooled, and the temperature of heating element 31 can be maintained at a desired temperature.

[0034] In the cooling device 1 described above, the volume of the narrowed portion 23 in the heater section 17 is smaller than the volumes of the first electrode 19 and the second electrode 21, and the narrowed portion 23 is formed so that the narrowed cross-sectional area CS3 decreases along the extension direction of the flow path 7. As a result, when power is supplied from the heater power supply 27, a temperature gradient is generated in the narrowed portion 23, causing the refrigerant to flow.

[0035] The power required to generate heat from the heater section 17, supplied from the heater power supply 27, is less than the power required to drive the pump that circulates the refrigerant. As a result, the cooling device 1 can reduce the power consumption required to cool the heating element 31, thereby achieving power saving in the cooling device 1.

[0036] In the above-described cooling device 1, the positive electrode 29a is electrically connected to the first electrode 19 and the negative electrode 29b is electrically connected to the second electrode 21. However, the negative electrode 29b may be electrically connected to the first electrode 19 and the positive electrode 29a may be electrically connected to the second electrode 21. That is, a current may flow through the heater portion 17 in a direction that reduces the constriction cross-sectional area CS3 of the constriction portion 23, or conversely, in a direction that increases the constriction cross-sectional area CS3 of the constriction portion 23.

[0037] Embodiment 2 In embodiment 2, an example of a variation of the heater section 17 in the cooling device 1 will be described. As shown in Figures 11 and 12, the first electrode 19 and the second electrode 21 in the heater section 17 are arranged with a gap between them along the Y-axis direction. The narrowed section 23 is arranged to connect the first electrode 19 and the second electrode 21. The narrowed section 23 includes a first section 23a and a second section 23b. The first section 23a and the second section 23b are formed with a gap between them in the X-axis direction.

[0038] In this case, the cross-sectional area of ​​the path set in the heater portion 17, which serves as the current path, is the cross-sectional area of ​​the X-Z cross section, which is a cross section along the X-axis direction. In this case, the current may flow from the first electrode 19 to the second electrode 21, or conversely, from the second electrode 21 to the first electrode 19.

[0039] As shown in Figures 13 and 14, the first portion 23a has a width WDD. The second portion 23b has a width WDC. The width WDD is, for example, 10 µm. The width WDC is, for example, several tens of µm. The distance between the first portion 23a and the second portion 23b is, for example, several µm. The first narrowed cross-sectional area CS3D of the first portion 23a is the width WDD x thickness. The second narrowed cross-sectional area CS3C of the second portion 23b is the width WDC x thickness.

[0040] That is, the narrowed cross-sectional area CS3 has a first narrowed cross-sectional area CS3D and a second narrowed cross-sectional area CS3C. The first narrowed cross-sectional area CS3D and the second narrowed cross-sectional area CS3C are each a constant value. The first narrowed cross-sectional area CS3D is smaller than the second narrowed cross-sectional area CS3C.

[0041] The magnitude relationship of the path cross-sectional area CS will be explained with reference to Fig. 14. The upper part of Fig. 14 shows the three-dimensional structure of the heater section 17, with the X-Z plane appearing. The middle part of Fig. 14 shows the end face (X-Z end face) of the first electrode 19 of the heater section 17 to which the narrowed section 23 (first portion 23a and second portion 23b) is connected. The lower part of Fig. 14 shows the end face (X-Z end face) of the second electrode 21 of the heater section 17 to which the narrowed section 23 (first portion 23a and second portion 23b) is connected.

[0042] As shown in the middle of Figure 14, the first constriction cross-sectional area CS3D and the second constriction cross-sectional area CS3C are each smaller than the first electrode cross-sectional area CS1. Furthermore, the combined constriction cross-sectional area CS3 of the constriction portion 23, which is the first constriction cross-sectional area CS3D and the second constriction cross-sectional area CS3C, is also smaller than the first electrode cross-sectional area CS1. As shown in the bottom of Figure 14, the first constriction cross-sectional area CS3D and the second constriction cross-sectional area CS3C are each smaller than the second electrode cross-sectional area CS2. Furthermore, the combined constriction cross-sectional area CS3 of the constriction portion 23, which is the first constriction cross-sectional area CS3D and the second constriction cross-sectional area CS3C, is also smaller than the second electrode cross-sectional area CS2.

[0043] The narrowed portion 23 is formed such that the narrowed cross-sectional area CS3 decreases stepwise by a constant value along the X-axis direction and is discontinuous. Note that the other configuration is similar to that of the cooling device 1 shown in Figures 1, 2, and 3, so the same members are denoted by the same reference numerals and description thereof will not be repeated unless necessary.

[0044] Next, the operation (mechanism) of the cooling device 1 described above will be described. When the heater power supply 27 supplies power to the heater section 17, the temperature of the narrowed section 23 in the heater section 17 rises. Here, the first narrowed cross-sectional area CS3D of the first section 23a is smaller than the second narrowed cross-sectional area CS3C of the second section 23b. Therefore, the temperature of the first section 23a becomes higher than the temperature of the second section 23b. As a result, the refrigerant 5 in contact with the first section 23a vaporizes, generating bubbles 41 (microbubbles), as shown in FIG. 15 .

[0045] At this time, on the negative side of the X-axis from first portion 23a where bubble 41 is generated, second portion 23b, which has a lower temperature than first portion 23a, is located. On the other hand, on the positive side of the X-axis from first portion 23a, the gap (space) between first electrode 19 and second electrode 21 is located. As a result, the temperature of refrigerant 5 located on the negative side of the X-axis from generated bubble 41 is higher than the temperature of refrigerant 5 located on the positive side of the X-axis from bubble 41.

[0046] Therefore, as described above, a temperature gradient occurs at the interface between the refrigerant 5 and the bubble 41, and a shear force called a Marangoni force is generated due to the temperature gradient. That is, a shear force is generated when a high-temperature portion of the refrigerant 5 pulls on a low-temperature portion of the refrigerant 5. This shear force causes the refrigerant 5 to flow in the positive direction of the X-axis, as indicated by the arrow YA.

[0047] 16 and 17 , in cooling device 1, the generation of bubbles 41 causes refrigerant 5 to flow through flow path 7, including flow path 7a, as shown by arrow YA. Flow path 7 allows refrigerant 5 to flow in a circular pattern between heat absorption portion 9 and heat radiation portion 11. Heat generated from heat-generating element 31 is absorbed by refrigerant 5 at heat absorption portion 9. The heat absorbed by refrigerant 5 is radiated at heat radiation portion 11. By flowing refrigerant 5 in a circular pattern between heat absorption portion 9 and heat radiation portion 11, heat-generating element 31 can be continuously cooled, and the temperature of heat-generating element 31 can be maintained at a desired temperature.

[0048] In the cooling device 1 described above, the volume of the narrowed portion 23 (first portion 23a and second portion 23b) in the heater portion 17 is smaller than the volume of each of the first electrode 19 and the second electrode 21, and the narrowed portion 23 is formed such that the narrowed cross-sectional area CS3 decreases in the order of the second portion 23b and the first portion 23a along the direction in which the flow path 7 extends. As a result, when power is supplied from the heater power supply 27, a temperature gradient is generated in the narrowed portion 23, causing the refrigerant to flow.

[0049] The power required to generate heat from the heater section 17, supplied from the heater power supply 27, is less than the power required to drive the pump that circulates the refrigerant. As a result, the cooling device 1 can reduce the power consumption required to cool the heating element 31, thereby achieving power saving in the cooling device 1.

[0050] Embodiment 3 In embodiment 3, an example of a heating element 31 equipped with a cooling device 1 will be described. As shown in Figures 18 and 19, a heating element power supply 33 that drives the heating element 31 includes a heater power supply 27 that supplies power to the heater portion 17 of the cooling device 1.

[0051] Positive electrode 35a of heating element power supply 33 is electrically connected to a corresponding terminal (not shown) of heating element 31. Positive electrode 35a is also electrically connected to first electrode 19. Negative electrode 35b of heating element power supply 33 is electrically connected to a corresponding terminal (not shown) of heating element 31. Negative electrode 35b is also electrically connected to second electrode 21. Note that other configurations are similar to those shown in Figures 1, 2 and 3, and therefore the same members are designated by the same reference numerals, and description thereof will not be repeated unless necessary.

[0052] Next, the operation of the heating element 31 including the cooling device 1 will be described. When power is supplied to the heater portion 17 from the heating element power supply 33, the temperature of the constricted portion 23 in the heater portion 17 rises, and a bubble 41 is generated. At this time, as described in the first embodiment, the temperature of the refrigerant 5 located on the negative side of the X-axis relative to the generated bubble 41 is higher than the temperature of the refrigerant 5 located on the positive side of the X-axis relative to the bubble 41. Therefore, a temperature gradient is generated at the interface between the refrigerant 5 and the bubble 41, and a shear force called the Marangoni force resulting from the temperature gradient causes the refrigerant 5 to flow in the positive direction of the X-axis, as indicated by the arrow YA (see FIG. 8 ).

[0053] 20 and 21 , in cooling device 1, the generation of bubbles 41 causes refrigerant 5 to flow through flow path 7, including flow path 7a, as shown by arrow YA. Flow path 7 allows refrigerant 5 to flow in a circular pattern between heat absorption portion 9 and heat radiation portion 11. Heat generated from heat-generating element 31 is absorbed by refrigerant 5 at heat absorption portion 9. The heat absorbed by refrigerant 5 is radiated at heat radiation portion 11. By flowing refrigerant 5 in a circular pattern between heat absorption portion 9 and heat radiation portion 11, heat-generating element 31 can be continuously cooled, and the temperature of heat-generating element 31 can be maintained at a desired temperature.

[0054] In the heating element 31 equipped with the cooling device 1 described above, as explained in the first embodiment, the power supplied from the heater power supply 27 is less than the power required to drive the pump that circulates the refrigerant. The heater power supply 27 is included in the heating element power supply 33 that drives the heating element 31, thereby eliminating the need to provide a separate heater power supply. As a result, in addition to saving power in the cooling device 1, this can contribute to cost reduction.

[0055] In the above-described embodiments, a semiconductor laser device has been described as an example of the heating element 31. The heating element 31 is not limited to a semiconductor laser device, and may be, for example, a heat-generating device such as an IGBT (Insulated Gate Bipolar Transistor) or other power semiconductor device. Furthermore, as an arrangement mode of the cooling device 1, a case has been described in which the cooling device 1 is arranged so that the mounting surface of the housing 3 on which the heating element 31 is placed faces upward. However, the cooling device 1 may also be arranged so that the mounting surface of the housing 3 faces vertically, and there is no particular restriction on the direction of gravity.

[0056] The cooling devices 1 described in the respective embodiments can be combined in various ways as needed.

[0057] The embodiments disclosed herein are examples and are not intended to be limiting. The scope of the present disclosure is defined by the scope of the claims, not the scope described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

[0058] The present disclosure is effectively applied to a cooling device for cooling a heat-generating body.

[0059] 1 Cooling device, 3 Housing, 5 Refrigerant, 7 Flow path, 7a Flow path, 9 Heat absorption portion, 11 Heat dissipation portion, 13 Fin, 17 Heater portion, 19 First electrode, 21 Second electrode, 23 Narrowing portion, 23a First portion, 23b Second portion, 25a, 25b Region, CS Path cross-sectional area, CS1 First electrode cross-sectional area, CS2 Second electrode cross-sectional area, CS3 Narrowing cross-sectional area, CS3A Narrowing cross-sectional area, CS3B Narrowing cross-sectional area, CS3C Second Narrowing cross-sectional area, CS3D First Narrowing cross-sectional area, 27 Heater power supply, 29a Positive electrode, 29b Negative electrode, 31 Heating element, 33 Heating element power supply, 35a Positive electrode, 35b Negative electrode, 41 Air bubble, YA Arrow, WD, WDA, WDB, WDC, WDD Width, TL1, TL2 center line.

Claims

1. A cooling device for cooling a heat-generating body, comprising: a housing containing a refrigerant; a heat absorption section provided in the housing and causing the refrigerant to absorb heat from the heat-generating body; a heat dissipation section provided in the housing and causing the refrigerant to dissipate the heat absorbed by the refrigerant; and a heater section disposed within the housing and generating heat by current supplied from a heater power supply, wherein the housing has a flow path through which the refrigerant flows in a circular pattern between the heat absorption section and the heat dissipation section, and the heater section comprises: a first electrode; a second electrode disposed at an interval from the first electrode; and a constriction section which is an electrode connecting the first electrode and the second electrode, wherein a path cross-sectional area is set in the heater section, and the path cross-sectional area of ​​the constriction section is a constriction cross-sectional area, and the constriction section is formed in a manner such that the constriction cross-sectional area becomes smaller along a first direction.

2. The cooling device of claim 1, wherein the path cross-sectional area in the first electrode of the heater section is a first electrode cross-sectional area, the path cross-sectional area in the second electrode of the heater section is a second electrode cross-sectional area, and the constriction cross-sectional area is smaller than both the first electrode cross-sectional area and the second electrode cross-sectional area.

3. A cooling device as described in claim 1 or 2, wherein the narrowed portion is formed in such a manner that the power supplied from the heater power supply vaporizes the refrigerant to generate bubbles, and a temperature gradient is generated in the temperature of the refrigerant in contact with the bubbles.

4. A cooling device according to any one of claims 1 to 3, wherein the first electrode and the second electrode are arranged with a gap in the first direction, and the narrowed portion is formed so that the narrowed cross-sectional area becomes smaller along the first direction.

5. The cooling device according to claim 4, wherein said narrowed portion is formed in such a manner that said narrowed cross-sectional area decreases monotonically along said first direction.

6. A cooling device as described in claim 1, wherein the first electrode and the second electrode are arranged at an interval in a second direction intersecting the first direction, the constriction portion includes a first constriction portion and a second constriction portion formed at an interval in the first direction relative to the first constriction portion, the constriction cross-sectional area of ​​the first constriction portion is a first constriction cross-sectional area, the constriction cross-sectional area of ​​the second constriction portion is a second constriction cross-sectional area, and the first constriction portion and the second constriction portion are formed at an interval along the first direction such that the first constriction cross-sectional area is smaller than the second constriction cross-sectional area.

7. A cooling device according to claim 6, wherein the narrowed portion is formed such that the second narrowed cross-sectional area and the first narrowed cross-sectional area decrease stepwise along the first direction and are discontinuous.

8. A cooling device according to any one of claims 1 to 7, wherein the heat absorption portion is provided in a portion of the flow path that faces the heat generating element to be disposed in the housing.

9. The cooling device according to any one of claims 1 to 8, wherein the heat dissipation portion includes a plurality of fins attached to the flow path.

10. The cooling device according to any one of claims 1 to 9, wherein the refrigerant comprises any one selected from the group consisting of water, alcohol, ketone, glycol ether, and ester.

11. A heating element comprising a cooling device according to any one of claims 1 to 10, further comprising a heating element power supply for driving the heating element, the heating element power supply including the heater power supply.

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