Heat exchanger, cooling device, projector, and electronic apparatus

Abstract

To provide a heat exchanger that can increase heat exchange efficiency, a cooling device, a projector, and an electronic apparatus.SOLUTION: A heat exchanger comprises: a housing that has a storage chamber surrounded by first to fourth side faces; a first main channel that extends in the storage chamber toward the second side face along the third side face; a second main channel that extends in the storage chamber toward the second side face along the fourth side face; a third main channel that extends in the storage chamber toward the first side face between the first main channel and the second main channel; first sub channels that are provided at a plurality of parts of the first main channel; second sub channels that are provided at a plurality of parts of the second main channel; a plurality of third sub channels that are provided in the third main channel; a plurality of fourth sub channels that are provided in the third main channel; a first circulation port that is arranged in a range from the half of the length from the center of the first side face to the third side face to the third side face in the first side face; a second circulation port that is arranged in a range from the half of the length from the center of the first side face to the fourth side face to the fourth side face in the first side face; and a third circulation port that is arranged in the second side face.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a heat exchanger, a cooling device, a projector, and an electronic device. [Background technology]

[0002] BACKGROUND ART Conventionally, a heat sink is known that has a flow path formed therein through which a coolant flows (see, for example, Patent Document 1). The heat sink described in Patent Document 1 has multiple fluid channels formed therein. The multiple fluid channels are formed to carry a coolant from an inlet to an outlet of a slab, which is a plate-like structure. The multiple fluid channels include at least two main channels and multiple bridging channels connecting the at least two main channels. Each of the bridging channels has a cross section that locally increases and locally decreases in the direction of coolant flow, i.e., from one main channel to the other, and heat exchange between the coolant and the heat sink occurs in such a bridging channel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2020-522144 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the heat sink described in Patent Document 1 has an increased contact area with the coolant and improves the efficiency of heat exchange with the coolant, it may not be sufficient as a cooling structure for a heat source that generates a large amount of heat. For this reason, there has been a demand for a heat exchanger configuration with improved heat exchange efficiency. [Means for solving the problem]

[0005] A heat exchanger according to a first aspect of the present disclosure includes a housing having a first side surface and a second side surface located opposite to each other, a third side surface and a fourth side surface that intersect the first side surface and the second side surface, respectively, and are located opposite to each other, and a storage chamber surrounded by the first side surface, the second side surface, the third side surface, and the fourth side surface; a first main flow path extending within the storage chamber along the third side surface toward the second side surface; a second main flow path extending within the storage chamber along the fourth side surface toward the second side surface; a third main flow path provided within the storage chamber between the first main flow path and the second main flow path and extending toward the first side surface; a plurality of first branch flow paths provided at a plurality of locations on the first main flow path and branching off from the first main flow path; a plurality of second branch flow paths provided at a plurality of locations on the second main flow path and branching off from the second main flow path; a third tributary flow path provided in a plurality of portions on the first main flow path side, the third tributary flow path communicating with at least one first tributary flow path among the plurality of first tributary flow paths; a fourth tributary flow path provided in a plurality of portions on the third main flow path side, the fourth tributary flow path communicating with at least one second tributary flow path among the plurality of second tributary flow paths; a first circulation port disposed on the first side surface in a range from halfway along the length from the center of the first side surface to the third side surface to the third side surface, communicating the outside of the housing with the first main flow path and allowing a refrigerant to flow; a second circulation port disposed on the first side surface in a range from halfway along the length from the center of the first side surface to the fourth side surface, communicating the outside of the housing with the second main flow path and allowing a refrigerant to flow; and a third circulation port disposed on the second side surface, communicating the outside of the housing with the third main flow path and allowing a refrigerant to flow.

[0006] A cooling device according to a second aspect of the present disclosure includes the heat exchanger according to the first aspect, a radiator that radiates heat received by the refrigerant in the heat exchanger, and a pump that circulates the refrigerant between the heat exchanger and the radiator.

[0007] A projector according to a third aspect of the present disclosure comprises a cooling device according to the second aspect described above, a light source, an optical modulation element that modulates light emitted from the light source, a projection optical device that projects the modulated light, and a heat receiving plate provided on one of the heat generating elements of the light source and the optical modulation element, and the heat exchanger of the cooling device is connected to the heat receiving plate in a manner that allows heat transfer.

[0008] An electronic device according to a fourth aspect of the present disclosure comprises a cooling device according to the second aspect and a heat generating element having a heat receiving plate, and the heat exchanger of the cooling device is connected to the heat receiving plate in a manner that allows heat transfer. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a projector according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 3] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 4] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 5] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 6] FIG. 2 is a cross-sectional view showing the internal configuration of the heat exchanger according to the first embodiment. [Figure 7] 4 is a graph showing the heat transfer efficiency to the refrigerant of the heat exchanger according to the first embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing the internal configuration of a heat exchanger provided in a cooling device of a projector according to a second embodiment. [Figure 9] 10 is a graph showing the efficiency of heat transfer to a refrigerant in a heat exchanger according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings. [Projector configuration] FIG. 1 is a schematic diagram showing the configuration of a projector 1 according to this embodiment. The projector 1 according to this embodiment is an example of an electronic device, and is an image display device that modulates light emitted from a light source to form image light according to image information, and enlarges and projects the formed image light onto a projection surface SC such as a screen. As shown in Fig. 1, the projector 1 includes an image projection device 2 and a cooling device 3. In addition, although not shown, the projector 1 also includes a control device that controls the projector 1, a power supply device that supplies power to the electronic components of the projector 1, and an exterior housing that houses the image projection device 2, cooling device 3, control device, and power supply device.

[0011] [Configuration of image projection device] The image projection device 2 generates the image light described above and projects the generated image light. The image projection device 2 includes three light sources 21, three heat receiving plates 22, three light modulation elements 23, a color combining element 24, and a projection optical device 25. The three light sources 21 emit light that illuminates the three light modulation elements 23. The three light sources 21 include a red light source 21R, a green light source 21G, and a blue light source 21B. The red light source 21R emits red light to the red light modulation element 23R of the light modulation element 23. Green light source 21G emits green light to green light modulation element 23G of light modulation element 23. The blue light source 21B emits blue light to the blue light modulation element 23B of the light modulation element 23. In this embodiment, the red light source 21R, the green light source 21G, and the blue light source 21B are each configured by a light emitting element that emits light of the corresponding color. Examples of the light emitting element include solid-state light sources such as an LED (Light Emitting Diode) and an LD (Laser Diode). Each of the three heat receiving plates 22 is disposed at a corresponding one of the three light sources 21. That is, the three heat receiving plates 22 include a heat receiving plate 22R heat-transferably connected to the red light source 21R, a heat receiving plate 22G heat-transferably connected to the green light source 21G, and a heat receiving plate 22B heat-transferably connected to the blue light source 21B. Each heat receiving plate 22 is heat-transferably connected to a heat exchanger 4, which will be described later.

[0012] Each of the three light modulation elements 23 modulates incident light in accordance with image information input from the control device. The three light modulation elements 23 include a red light modulation element 23R, a green light modulation element 23G, and a blue light modulation element 23B. The red light modulation element 23R modulates the red light incident from the red light source 21R. The green light modulation element 23G modulates the green light incident from the green light source 21G. The blue light modulation element 23B modulates the blue light incident from the blue light source 21B. Each light modulation element 23R, 23G, 23B can be constructed by a liquid crystal light valve having a transmissive liquid crystal panel, an incident side polarizer provided on the light incident side of the transmissive liquid crystal panel, and an exit side polarizer provided on the light exit side of the transmissive liquid crystal panel.

[0013] The color combining element 24 combines the red light, green light, and blue light incident from the light modulation elements 23R, 23G, and 23B to form image light, and outputs the formed image light to the projection optical device 25. In this embodiment, the color combining element 24 is configured by a cross dichroic prism. However, the present invention is not limited to this, and the color combining element 24 can also be configured by a plurality of dichroic mirrors. The projection optical device 25 projects the image light incident from the color synthesis element 24 onto the projection surface SC. The projection optical device 25 can be configured as a lens assembly including, for example, a plurality of lenses and a lens barrel that houses the plurality of lenses.

[0014] [Cooling system configuration] The cooling device 3 cools the heat generating elements of the projector 1. The cooling device 3 includes a plurality of heat exchangers 4, a reservoir 31, a radiator 32, a pump 33, and a plurality of pipes 34, and circulates a refrigerant to cool the heat generating elements connected to the heat exchanger 4. In this embodiment, the refrigerant is a liquid refrigerant, but it may also be a gas refrigerant.

[0015] The plurality of pipes 34 connect the plurality of heat exchangers 4, the reservoir 31, the radiator 32, and the pump 33 so that the refrigerant can flow therethrough, thereby forming a refrigerant circulation flow path. The plurality of pipes 34 include a first pipe 341, a second pipe 342, a third pipe 343, a fourth pipe 344, a fifth pipe 345, and a sixth pipe 346. The first pipe 341 connects the red heat exchanger 4R, among the multiple heat exchangers 4, to the reservoir 31. In this embodiment, the first pipe 341 connects a third flow port 57 (described later) of the red heat exchanger 4R to the reservoir 31. That is, the first pipe 341 circulates the refrigerant discharged from the third flow port 57 of the red heat exchanger 4R to the reservoir 31. The second pipe 342 connects the reservoir 31 and the radiator 32 . The third pipe 343 connects the radiator 32 and the pump 33 .

[0016] The fourth pipe 344 connects the pump 33 to the blue heat exchanger 4B among the multiple heat exchangers 4. In the present embodiment, the fourth pipe 344 connects the pump 33 to the first circulation port 55 and the second circulation port 56 of the blue heat exchanger 4B. That is, the fourth pipe 344 divides the refrigerant delivered from the pump 33 into two, and causes one of the two refrigerants to flow through the first circulation port 55 and the other refrigerant to flow through the second circulation port 56. The fifth pipe 345 connects the blue heat exchanger 4B and the green heat exchanger 4G among the multiple heat exchangers 4. In this embodiment, the fifth pipe 345 connects the third flow port 57 of the blue heat exchanger 4B to the first flow port 55 and the second flow port 56 of the green heat exchanger 4G. That is, the fifth pipe 345 divides the refrigerant discharged from the third flow port 57 of the blue heat exchanger 4B into two, and causes one of the two refrigerants to flow through the first flow port 55 of the green heat exchanger 4G and the other refrigerant to flow through the second flow port 56 of the green heat exchanger 4G.

[0017] The sixth pipe 346 connects the green heat exchanger 4G and the red heat exchanger 4R. In this embodiment, the sixth pipe 346 connects the third flow port 57 of the green heat exchanger 4G to the first flow port 55 and the second flow port 56 of the red heat exchanger 4R. That is, the sixth pipe 346 divides the refrigerant discharged from the third flow port 57 of the green heat exchanger 4G into two, and causes one of the two refrigerants to flow through the first flow port 55 of the red heat exchanger 4R and the other refrigerant to flow through the second flow port 56 of the red heat exchanger 4R.

[0018] The reservoir 31 is a tank that temporarily stores the refrigerant that has circulated through the plurality of heat exchangers 4. The radiator 32 cools the refrigerant flowing in from the reservoir 31. That is, the radiator 32 radiates heat received by the refrigerant in the heat exchanger 4. The radiator 32 has a plurality of fine flow paths 321 therein through which the refrigerant flows, and cools the refrigerant by receiving heat from the refrigerant in each of the fine flow paths. The refrigerant cooled by the radiator 32 flows to the pump 33 via a third pipe 343. The radiator 32 radiates the heat received from the refrigerant to a cooling gas flowing from a fan (not shown). The pump 33 circulates the refrigerant between the heat exchanger 4 and the radiator 32. The pump 33 sends the refrigerant circulating from the radiator 32 to the plurality of heat exchangers 4. In this embodiment, the pump 33 sends the refrigerant to the blue heat exchanger 4B via the fourth pipe 344.

[0019] [Heat exchanger configuration] Each of the plurality of heat exchangers 4 is a so-called cold plate, and transfers heat received from a heating element to a refrigerant flowing inside, thereby cooling the heating element. The plurality of heat exchangers 4 are connected to a heat receiving plate 22 disposed on a light source 21, which is one of the heating elements in this embodiment, so as to be able to transfer heat. The plurality of heat exchangers 4 include a red heat exchanger 4R, a green heat exchanger 4G, and a blue heat exchanger 4B. The red heat exchanger 4R is connected to the heat receiving plate 22R so as to be capable of transferring heat therethrough. The green heat exchanger 4G is connected to the heat receiving plate 22G so as to be capable of transferring heat therethrough. The blue heat exchanger 4B is connected to the heat receiving plate 22B so as to be capable of transferring heat therethrough.

[0020] [Case configuration] FIG. 2 is a cross-sectional view showing the internal configuration of heat exchanger 4. Specifically, FIG. 2 is a cross-sectional view showing the internal configuration of heat exchanger 41 of heat exchanger 4. The cross-sectional view has a first flow port 55 located at a position spaced apart from center 51C of first side surface 51 toward third side surface 53 by a distance of 1, where 1 is the distance from center 51C of first side surface 51 to third side surface 53, and a second flow port 56 located at a position spaced apart from center 51C toward fourth side surface 54 by a distance of 1, where 1 is the distance from center 51C of first side surface 51 to fourth side surface 54. In FIG. 2, for ease of viewing, only some of the multiple first tributary channels 621 are labeled with reference numerals. The same applies to second tributary channels 622, third tributary channels 623, fourth tributary channels 624, first narrow tributary channels 631, and second narrow tributary channels 632. As shown in FIG. 2, each heat exchanger 4 includes a housing 5 formed in a substantially rectangular parallelepiped shape. The housing 5 is made of a metal such as copper having high thermal conductivity. The housing 5 has a first side surface 51, a second side surface 52, a third side surface 53, and a fourth side surface 54, and also has a flat-plate-shaped storage chamber 6 surrounded by the first side surface 51, the second side surface 52, the third side surface 53, and the fourth side surface 54.

[0021] The first side surface 51, the second side surface 52, the third side surface 53, and the fourth side surface 54 are each an outer surface of the housing 5. The first side surface 51 and the second side surface 52 are located on opposite sides to each other. The third side surface 53 and the fourth side surface 54 are located on opposite sides to each other. The third side surface 53 intersects with both the first side surface 51 and the second side surface 52. The fourth side surface 54 intersects with both the first side surface 51 and the second side surface 52.

[0022] Furthermore, the heat exchanger 4 has a first flow port 55 , a second flow port 56 , and a third flow port 57 . The first flow port 55 is disposed on the first side surface 51. The first flow port 55 is a communication port that communicates the outside of the housing 5 with the storage chamber 6 inside the housing 5. The first flow port 55 allows a refrigerant to flow through. The second flow port 56 is disposed on the first side surface 51. The second flow port 56 is a communication port that communicates between the outside of the housing 5 and the storage chamber 6 inside the housing 5. The second flow port 56 allows a refrigerant to flow through. The third flow port 57 is disposed at the center 52C of the second side surface 52. The third flow port 57 is a communication port that connects the outside of the housing 5 with the accommodation chamber 6. The third flow port 57 allows a refrigerant to flow through it.

[0023] In the following description, the three mutually orthogonal directions are referred to as the +X direction, the +Y direction, and the +Z direction. In this embodiment, the +X direction is the direction from the first side surface 51 to the second side surface 52, and the +Y direction is the direction from the fourth side surface 54 to the third side surface 53. The +Z direction is a direction orthogonal to both the +X direction and the +Y direction, and is, for example, a direction perpendicular to the paper surface on which FIG. 2 is shown. Although not shown, the direction opposite the +X direction is referred to as the -X direction, the direction opposite the +Y direction is referred to as the -Y direction, and the direction opposite the +Z direction is referred to as the -Z direction. The axis along the +X direction is referred to as the X axis, the axis along the +Y direction is referred to as the Y axis, and the axis along the +Z direction is referred to as the Z axis.

[0024] [Containment Room Configuration] When one of the first and second flow ports 55, 56, and the third flow port 57 is an inlet and the other is an outlet, the accommodation chamber 6 is a portion where heat transferred from the heating element to the refrigerant flowing inside is transferred and heat is exchanged between the refrigerant and the accommodation chamber 6. The accommodation chamber 6 includes a plurality of main flow channels 611, 612, and 613, a plurality of branch flow channels 621, 622, 623, and 624, and a plurality of narrow branch flow channels 631 and 632. The plurality of main flow channels 611, 612, and 613, the plurality of branch flow channels 621, 622, 623, and 624, and the plurality of narrow branch flow channels 631 and 632 can be formed in the housing 5 by, for example, 3D printing.

[0025] [Configuration of multiple main channels] Each of the plurality of main flow paths 611, 612, 613 is connected to a corresponding one of the flow paths 55 to 57, and is a flow path configured to allow the refrigerant to flow therethrough. The first main flow path 611 is connected to the first circulation port 55. The first main flow path 611 extends from the first circulation port 55 inside the storage chamber 6 along the third side surface 53 toward the second side surface 52. In the heat exchanger 41, the first main flow path 611 extends in a substantially straight line from the first circulation port 55 along the third side surface 53 toward the second side surface 52. The flow path cross-sectional area of ​​the first main flow path 611 becomes smaller as the first main flow path 611 moves toward the second side surface 52. The second main flow path 612 is connected to the second circulation port 56. The second main flow path 612 extends from the second circulation port 56 inside the storage chamber 6 along the fourth side surface 54 toward the second side surface 52. In the heat exchanger 41, the second main flow path 612 extends in a substantially straight line from the second circulation port 56 along the fourth side surface 54 toward the second side surface 52. The flow path cross-sectional area of ​​the second main flow path 612 decreases as the second main flow path 612 approaches the second side surface 52. The third main flow path 613 is connected to the third circulation port 57. The third main flow path 613 extends from the third circulation port 57 through the center of the storage chamber 6 toward the first side surface 51 when viewed from the +Z direction. That is, the third main flow path 613 extends along the X-axis between the first main flow path 611 and the second main flow path 612 in the Y-axis in the storage chamber 6. The flow path cross-sectional area of ​​the third main flow path 613 decreases as the third main flow path 613 approaches the first side surface 51.

[0026] [Multiple tributary configuration] The branch channels 621, 622, 623, and 624 are provided at multiple locations in the corresponding main channels of the main channels 611, 612, and 613, respectively, and are channels that branch off and extend from the main channels. The first branch channels 621 are provided at a plurality of locations on the first main channel 611, and extend by branching off from the first main channel 611. The cross-sectional area of ​​each of the plurality of first branch channels 621 is smaller than the cross-sectional area of ​​the first main channel 611. More specifically, the cross-sectional area of ​​each of the first branch channels 621 is smaller than the smallest cross-sectional area of ​​the first main channel 611. Each of the first branch channels 621 extends in a curved line. The second branch channels 622 are provided at a plurality of locations on the second main channel 612, and extend by branching off from the second main channel 612. The cross-sectional area of ​​each of the plurality of second branch channels 622 is smaller than the cross-sectional area of ​​the second main channel 612. More specifically, the cross-sectional area of ​​each of the second branch channels 622 is smaller than the smallest cross-sectional area of ​​the second main channel 612. Each of the second branch channels 622 extends in a curved line.

[0027] A plurality of third tributary channels 623 are provided in a portion of the third main channel 613 on the first main channel 611 side. That is, a plurality of third tributary channels 623 are provided in a portion of the third main channel 613 on the first main channel 611 side, in the +Y direction. At least one of the plurality of third tributary channels 623 communicates with at least one of the plurality of first tributary channels 621. Each of the third tributary channels 623 extends in a curved shape. A plurality of fourth tributary channels 624 are provided in a portion of the third main channel 613 on the second main channel 612 side. That is, a plurality of fourth tributary channels 624 are provided in a portion of the third main channel 613 on the second main channel 612 side, that is, in the -Y direction. At least one fourth tributary channel 624 of the plurality of fourth tributary channels 624 communicates with at least one second tributary channel 622 of the plurality of second tributary channels 622. Each fourth tributary channel 624 extends in a curved shape. The flow path cross-sectional area of ​​each third subchannel 623 is smaller than the flow path cross-sectional area of ​​the third main channel 613. More specifically, the flow path cross-sectional area of ​​each third subchannel 623 is smaller than the smallest flow path cross-sectional area in the third main channel 613. Similarly, the flow path cross-sectional area of ​​each fourth subchannel 624 is smaller than the flow path cross-sectional area of ​​the third main channel 613. More specifically, the flow path cross-sectional area of ​​each fourth subchannel 624 is smaller than the smallest flow path cross-sectional area in the third main channel 613.

[0028] [Configuration of multiple tributaries] Each of the plurality of first narrow tributary channels 631 connects one first tributary channel 621 and one third tributary channel 623. The channel cross-sectional area of ​​each first narrow tributary channel 631 is smaller than the channel cross-sectional area of ​​the first tributary channel 621 and the channel cross-sectional area of ​​the third tributary channel 623, respectively. There may be one first narrow tributary channel 631 provided for one first tributary channel 621 or one third tributary channel 623, or there may be a plurality of first narrow tributary channels 631 provided for one first tributary channel 621 or one third tributary channel 623. The first narrow tributary channels 631 extend in a curved shape. Each of the plurality of second narrow tributary channels 632 connects one second tributary channel 622 and one fourth tributary channel 624. The channel cross-sectional area of ​​each second narrow tributary channel 632 is smaller than the channel cross-sectional area of ​​the second tributary channel 622 and the channel cross-sectional area of ​​the fourth tributary channel 624, respectively. There may be one second narrow tributary channel 632 provided for one second tributary channel 622 or one fourth tributary channel 624, or there may be a plurality of second narrow tributary channels 632 provided for one second tributary channel 622 or one fourth tributary channel 624. The second narrow tributary channels 632 extend in a curved line.

[0029] [Connection status of each flow path] The first main channel 611 does not directly communicate with the third main channel 613. The first main channel 611 communicates with the third main channel 613 via at least one of the first branch channel 621, the third branch channel 623, and the first narrow branch channel 631. The second main channel 612 does not directly communicate with the third main channel 613. The second main channel 612 communicates with the third main channel 613 via at least one of the second branch channel 622, the fourth branch channel 624, and the second narrow branch channel 632.

[0030] [Another example of the arrangement of the first and second circulation ports] The position of the first circulation port 55 in the first side surface 51 that communicates with the first main flow path 611 and the position of the second circulation port 56 in the first side surface 51 that communicates with the second main flow path 612 can be made different depending on the heat exchanger 4. In other words, the distance between the center 51C of the first side surface 51 and the first circulation port 55, and the distance between the center 51C and the second circulation port 56 can be made different depending on the heat exchanger 4.

[0031] [Heat exchanger with first and second flow ports at 0.75° positions] 3 is a cross-sectional view showing the internal configuration of heat exchanger 42, in which first circulation port 55 is disposed at 0.75 in the +Y direction from center 51C and second circulation port 56 is disposed at 0.75 in the -Y direction from center 51C, of ​​heat exchanger 4. In FIG. 3, only some of the multiple first tributary channels 621 are labeled with reference numerals. The same applies to second tributary channel 622, third tributary channel 623, fourth tributary channel 624, first narrow tributary channel 631, and second narrow tributary channel 632. For example, as shown in FIG. 3, heat exchanger 42, which is one of heat exchangers 4, has the same configuration and function as heat exchanger 41 described above, except that the positions of the first circulation port 55 and the second circulation port 56 on the first side surface 51 are different and the extension directions of the first main flow path 611 and the second main flow path 612 are different. In the heat exchanger 42, when the length from the center 51C of the first side surface 51 to the third side surface 53 is defined as 1, the first circulation port 55 is disposed 0.75 away from the center 51C toward the third side surface 53. Similarly, in the heat exchanger 42, when the length from the center 51C of the first side surface 51 to the fourth side surface 54 is defined as 1, the second circulation port 56 is disposed 0.75 away from the center 51C toward the fourth side surface 54.

[0032] In the heat exchanger 42, the first main flow path 611 connected to the first flow port 55 extends from the first flow port 55 toward the third side surface 53 at an angle of approximately 75° with respect to a perpendicular line to the first side surface 51, and then extends along the third side surface 53 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the first main flow path 611 becomes smaller as the first main flow path 611 extends from the first flow port 55. Similarly, in the heat exchanger 42, the second main flow path 612 connected to the second flow port 56 extends from the second flow port 56 toward the fourth side surface 54 at an angle of approximately 75° with respect to a perpendicular line to the first side surface 51, and then extends along the fourth side surface 54 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the second main flow path 612 becomes smaller as the second main flow path 612 extends from the second flow port 56.

[0033] [Heat exchanger with first and second flow ports at 0.5 position] 4 is a cross-sectional view showing the internal configuration of heat exchanger 43, in which first circulation port 55 is disposed at 0.5 in the +Y direction from center 51C and second circulation port 56 is disposed at 0.5 in the -Y direction from center 51C, of ​​heat exchanger 4. In FIG. 4, only some of the multiple first tributary channels 621 are labeled with reference numerals. The same applies to second tributary channel 622, third tributary channel 623, fourth tributary channel 624, first narrow tributary channel 631, and second narrow tributary channel 632. For example, as shown in FIG. 4, heat exchanger 43, which is one of heat exchangers 4, has the same configuration and function as heat exchanger 41 described above, except that the positions of the first circulation port 55 and the second circulation port 56 on the first side surface 51 are different and the extension directions of the first main flow path 611 and the second main flow path 612 are different. In heat exchanger 43, when the length from center 51C of first side surface 51 to third side surface 53 is defined as 1, first circulation port 55 is disposed 0.5 away from center 51C toward third side surface 53. Similarly, in heat exchanger 43, when the length from center 51C of first side surface 51 to fourth side surface 54 is defined as 1, second circulation port 56 is disposed 0.5 away from center 51C toward fourth side surface 54.

[0034] In the heat exchanger 43, the first main flow path 611 connected to the first flow port 55 extends from the first flow port 55 toward the third side surface 53 at an angle of approximately 60° with respect to a perpendicular line to the first side surface 51, and then extends along the third side surface 53 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the first main flow path 611 becomes smaller as the first main flow path 611 extends from the first flow port 55. Similarly, in the heat exchanger 43, the second main flow path 612 connected to the second flow port 56 extends from the second flow port 56 toward the fourth side surface 54 at an angle of approximately 60° with respect to a perpendicular line to the first side surface 51, and then extends along the fourth side surface 54 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the second main flow path 612 becomes smaller as the second main flow path 612 extends from the second flow port 56.

[0035] In the heat exchanger 43, some of the multiple first tributary channels 621 are provided at the intersection between the first side surface 51 and the third side surface 53. Some of the first tributary channels 621 branch off from the first main channel 611 and communicate with the first main channel 611 again. Similarly, some of the multiple second tributary channels 622 are provided at the intersection between the first side surface 51 and the fourth side surface 54. Some of the second tributary channels 622 branch off from the second main channel 612 and communicate with the second main channel 612 again.

[0036] [Heat exchanger with first and second flow ports at 0.25 positions] 5 is a cross-sectional view showing the internal configuration of heat exchanger 44, in which first circulation port 55 is disposed at 0.25 in the +Y direction from center 51C and second circulation port 56 is disposed at 0.25 in the -Y direction from center 51C, of ​​heat exchanger 4. In FIG. 5, only some of the multiple first tributary channels 621 are labeled with reference numerals. The same applies to second tributary channel 622, third tributary channel 623, fourth tributary channel 624, first narrow tributary channel 631, and second narrow tributary channel 632. For example, as shown in FIG. 5, heat exchanger 44, which is one of heat exchangers 4, has the same configuration and function as heat exchanger 41 described above, except that the positions of the first circulation port 55 and the second circulation port 56 on the first side surface 51 are different and the extension directions of the first main flow path 611 and the second main flow path 612 are different. In the heat exchanger 44, the first flow port 55 is positioned 0.25 away from the center 51C of the first side surface 51 toward the third side surface 53, assuming that the length from the center 51C of the first side surface 51 to the third side surface 53 is 1. Similarly, in the heat exchanger 44, the second flow port 56 is positioned 0.25 away from the center 51C of the first side surface 51 toward the fourth side surface 54, assuming that the length from the center 51C of the first side surface 51 to the fourth side surface 54 is 1.

[0037] In the heat exchanger 44, the first main flow path 611 connected to the first flow port 55 extends from the first flow port 55 toward the third side surface 53 along a line perpendicular to the first side surface 51, and then extends toward the third side surface 53 at an angle of approximately 90° with respect to the line perpendicular to the first side surface 51, and then extends along the third side surface 53 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the first main flow path 611 becomes smaller as the first main flow path 611 extends from the first flow port 55. Similarly, in the heat exchanger 44, the second main flow path 612 connected to the second flow port 56 extends from the second flow port 56 toward the fourth side surface 54 along the perpendicular to the first side surface 51, and then extends toward the fourth side surface 54 at an angle of approximately 90° with respect to the perpendicular to the first side surface 51, and then extends along the fourth side surface 54 toward the second side surface 52. In this case, the flow path cross-sectional area of ​​the second main flow path 612 becomes smaller as the second main flow path 612 extends from the second flow port 56.

[0038] In the heat exchanger 44, some of the multiple first tributary channels 621 are provided at the intersection of the first side surface 51 and the third side surface 53. Some of the first tributary channels 621 branch off from the first main channel 611, then further branch off and communicate with the first main channel 611 again. Similarly, some of the multiple second tributary channels 622 are provided at the intersection of the first side surface 51 and the fourth side surface 54. Some of the second tributary channels 622 branch off from the second main channel 612, then further branch off and communicate with the second main channel 612 again.

[0039] [Heat exchanger with first and second flow ports at position 0] 6 is a cross-sectional view showing the internal configuration of a heat exchanger 45 in which a first flow port 55 is arranged at position 0 in the +Y direction from the center 51C and a second flow port 56 is arranged at position 0 in the -Y direction from the center 51C. That is, FIG. 6 is a cross-sectional view showing the internal configuration of a heat exchanger 45 in which the first flow port 55 and the second flow port 56 are each arranged at the center 51C. In FIG. 6, only some of the multiple first tributary channels 621 are denoted with reference numerals. The same applies to the second tributary channel 622, the third tributary channel 623, the fourth tributary channel 624, the first narrow tributary channel 631, and the second narrow tributary channel 632. For example, as shown in FIG. 6, heat exchanger 45, which is one of heat exchangers 4, has the same configuration and function as heat exchanger 41 described above, except that the positions of the first circulation port 55 and the second circulation port 56 on the first side surface 51 are different and the extension directions of the first main flow path 611 and the second main flow path 612 are different. In the heat exchanger 45, when the length from the center 51C of the first side surface 51 to the third side surface 53 is defined as 1, the first flow port 55 is disposed away from the center 51C toward the third side surface 53 by a length of 0. Similarly, when the length from the center 51C of the first side surface 51 to the fourth side surface 54 is defined as 1, the second flow port 56 is disposed away from the center 51C toward the fourth side surface 54 by a length of 0. That is, in the heat exchanger 45, the first flow port 55 and the second flow port 56 are disposed at the center 51C of the first side surface 51 so as to be shifted from each other along the Z axis.

[0040] In the heat exchanger 45, the first main flow path 611 connected to the first flow port 55 extends from the first flow port 55 toward the third side surface 53 at an angle of approximately 90° with respect to the perpendicular to the first side surface 51, and further extends toward the third side surface 53 at an angle of approximately 45° with respect to the perpendicular to the first side surface 51, and then extends along the third side surface 53 toward the second side surface 52. At this time, the flow path cross-sectional area of ​​the first main flow path 611 becomes smaller as the first main flow path 611 extends from the first flow port 55. Similarly, in the heat exchanger 45, the second main flow path 612 connected to the second flow port 56 extends from the second flow port 56 toward the fourth side surface 54 at an angle of approximately 90° with respect to the perpendicular to the first side surface 51, and further extends toward the fourth side surface 54 at an angle of approximately 45° with respect to the perpendicular to the first side surface 51, and then extends along the fourth side surface 54 toward the second side surface 52. In this case, the flow path cross-sectional area of ​​the second main flow path 612 becomes smaller as the second main flow path 612 extends from the second flow port 56.

[0041] In addition, the accommodation chamber 6 of the heat exchanger 45 is provided with a junction channel 64 that extends from the first circulation port 55 and the second circulation port 56 toward the second side surface 52 and branches off from the first main channel 611 and the second main channel 612 to join the first and second main channels 611 and 612. The junction channel 64 has a larger cross-sectional area than the cross-sectional areas of the first main channel 611 and the second main channel 612. The junction channel 64 is provided with some of the multiple first tributary channels 621, some of the multiple second tributary channels 622, some of the multiple first narrow tributary channels 631, and some of the multiple second narrow tributary channels 632.

[0042] In the heat exchanger 45, some of the multiple first tributary channels 621 are provided at the intersection of the first side surface 51 and the third side surface 53. Some of the first tributary channels 621 branch off from the first main channel 611, then branch off again and communicate with the first main channel 611 again. Similarly, in the heat exchanger 45, some of the multiple second tributary channels 622 are provided at the intersection of the first side surface 51 and the fourth side surface 54. Some of the second tributary channels 622 branch off from the second main channel 612, then branch off again, and communicate with the second main channel 612 again.

[0043] [Heat exchange efficiency of heat exchanger] FIG. 7 is a graph showing the heat transfer efficiency of the heat exchangers 41 to 45 to the refrigerant. Here, the heat exchange efficiency of the heat exchanger 4 changes depending on the positions of the first circulation port 55 and the second circulation port 56 on the first side surface 51. The inventors of the present disclosure investigated the heat exchange efficiency of the heat exchangers 41 to 45 described above with respect to the refrigerant. As a result, it was found that, as shown in Fig. 7, in the heat exchangers 41 to 43 in which the first circulation ports 55 and the second circulation ports 56 are arranged at positions that are 0.5 to 1 distance away from the center 51C of the first side surface 51, the heat transfer efficiency to the refrigerant is relatively high, and in the heat exchangers 44 and 45 in which the first circulation ports 55 and the second circulation ports 56 are arranged at positions that are 0 to less than 0.5 distance away from the center 51C of the first side surface 51, the heat transfer efficiency to the refrigerant is relatively low. Furthermore, it was found that the heat transfer efficiency to the refrigerant of heat exchangers 41 and 42, among heat exchangers 41 to 43, in which flow ports 55 and 56 are arranged at a position that is 0.75 to 1 length away from the center 51C of the first side surface 51, is higher than the heat transfer efficiency to the refrigerant of heat exchanger 43, in which flow ports 55 and 56 are arranged at a position that is 0.5 length away from the center 51C of the first side surface 51. Furthermore, it was found that among the heat transfer efficiencies of the heat exchangers 41 to 45, the heat transfer efficiency of the heat exchanger 42, in which the flow ports 55, 56 are located at a distance of 0.75 mm from the center 51C of the first side surface 51, is the highest.

[0044] The following reasons are considered to be the reasons why the heat exchange efficiency differs among the heat exchangers 41 to 45. The first reason is that in the heat exchangers 43, 44, and 45 in which the flow ports 55, 56 are disposed at a distance of 0 to 0.5 mm from the center 51C of the first side surface 51, the first main flow path 611 and the second main flow path 612 have portions that extend at a relatively large angle with respect to a perpendicular line to the first side surface 51. In the heat exchangers 43, 44, and 45, for example, if the flow ports 55, 56 are used as refrigerant flow ports and the flow port 57 is used as a refrigerant discharge port, the pressure loss of the refrigerant flowing from the flow ports 55, 56 into the accommodation chamber 6 increases, making it difficult for the refrigerant to flow smoothly into the accommodation chamber 6. For this reason, it is thought that heat transfer to the refrigerant is more difficult in the heat exchangers 44, 45 than in the other heat exchangers 41 to 43, resulting in a decrease in heat transfer efficiency.

[0045] A second reason is that in the heat exchangers 44 and 45, the intersections between the first side surface 51 and the third side surface 53 and the intersections between the first side surface 51 and the fourth side surface 54 cannot be effectively utilized. In the heat exchangers 41 to 45, the third main flow path 613 is provided between the first main flow path 611 and the second main flow path 612 along the Y axis. Therefore, when the flow ports 55 and 56 are used as refrigerant inlets and the flow port 57 is used as a refrigerant outlet, the refrigerant flows from the first main flow path 611 to the third main flow path 613 and from the second main flow path 612 to the third main flow path 613. On the other hand, when the flow port 57 is used as a refrigerant inlet and the flow ports 55 and 56 are used as refrigerant outlets, the refrigerant flows from the third main flow path 613 to the first main flow path 611 and from the third main flow path 613 to the second main flow path 612. In either case, the refrigerant that flows through the branch channels 621, 622 provided at each intersection travels a relatively short distance before returning to the corresponding main channels 611, 612, so the contact area between the inner surface of the channel and the refrigerant is not large, which is thought to make it difficult for heat to be transferred from the storage chamber to the refrigerant, resulting in a decrease in heat transfer efficiency.

[0046] In the heat exchanger 41, the first main flow path 611 extends from the first flow port 55 along the third side surface 53, and the second main flow path 612 extends from the second flow port 56 along the fourth side surface 54. Therefore, when the flow ports 55, 56 are used as refrigerant inlets, the refrigerant flowing in from the first flow port 55 quickly flows through the first main flow path 611 toward the second side surface 52, and the refrigerant flowing in from the second flow port 56 quickly flows through the second main flow path 612 toward the second side surface 52. Therefore, the refrigerant does not easily flow through the first branch flow path 621 provided on the first side surface 51 side of the first main flow path 611 and the second branch flow path 622 provided on the first side surface 51 side of the second main flow path 612. Therefore, it is considered that the heat exchange efficiency of the heat exchanger 41 with respect to the refrigerant is slightly lower than the heat exchange efficiency of the heat exchanger 42 with respect to the refrigerant.

[0047] For the above reasons, it is preferable to employ any one of the heat exchangers 41 to 43 for the cooling device 3, which has a first flow port 55 arranged at a distance of 0.5 to 1 from the center 51C of the first side surface 51 toward the third side surface 53, and a second flow port 56 arranged at a distance of 0.5 to 1 from the center 51C of the first side surface 51 toward the fourth side surface 54, when the length from the center 51C of the first side surface 51 to the fourth side surface 54 is defined as 1. Furthermore, it is preferable to employ any one of the heat exchangers 41, 42 for the cooling device 3, which has a first flow port 55 arranged at a distance of 0.75 to 1 from the center 51C of the first side surface 51 toward the third side surface 53, and a second flow port 56 arranged at a distance of 0.75 to 1 from the center 51C of the first side surface 51 toward the fourth side surface 54.

[0048] [Effects of the first embodiment] The projector 1 according to the present embodiment described above has the following advantages. The projector 1 corresponds to an electronic device and includes a cooling device 3 and a light source 21, which is a heat generating element, having a heat receiving plate 22. A heat exchanger 4 of the cooling device 3 is connected to the heat receiving plate 22 so as to be capable of transferring heat. More specifically, the projector 1 includes a light source 21, a heat receiving plate 22, a light modulation element 23, a projection optical device 25, and a cooling device 3. The heat receiving plate 22 is provided on the light source 21, which is one of the heat generating elements of the light source 21 and the light modulation element 23. A heat exchanger 4 of the cooling device 3 is connected to the heat receiving plate 22 so as to be capable of transferring heat. The light modulation element 23 modulates the light emitted from the light source 21. The projection optical device 25 projects the light modulated by the light modulation element 23. The cooling device 3 includes a heat exchanger 4, a radiator 32, and a pump 33. The radiator 32 radiates heat received by the refrigerant in the heat exchanger 4. The pump 33 circulates the refrigerant between the heat exchanger 4 and the radiator 32.

[0049] The heat exchanger 4 includes a housing 5, a first main flow path 611, a second main flow path 612, a third main flow path 613, a first branch flow path 621, a second branch flow path 622, a third branch flow path 623, a fourth branch flow path 624, a first flow port 55, a second flow port 56, and a third flow port 57. The housing 5 has a first side surface 51, a second side surface 52, a third side surface 53, a fourth side surface 54, and a storage chamber 6. The first side surface 51 and the second side surface 52 are located opposite each other. The third side surface 53 and the fourth side surface 54 intersect the first side surface 51 and the second side surface 52, respectively, and are located opposite each other. The storage chamber 6 is surrounded by the first side surface 51, the second side surface 52, the third side surface 53, and the fourth side surface 54. The first main flow path 611 extends inside the storage chamber 6 along the third side surface 53 toward the second side surface 52 . The second main flow path 612 extends inside the storage chamber 6 along the fourth side surface 54 toward the second side surface 52 . The third main channel 613 is provided in the storage chamber 6 between the first main channel 611 and the second main channel 612 , and extends toward the first side surface 51 .

[0050] The first branch channels 621 are provided at a plurality of locations on the first main channel 611. Each of the plurality of first branch channels 621 branches off from the first main channel 611. The second branch channels 622 are provided at a plurality of locations on the second main channel 612. Each of the plurality of second branch channels 622 branches off from the second main channel 612. A plurality of third tributary channels 623 are provided in a portion of the third main channel 613 on the first main channel 611 side. At least one of the plurality of third tributary channels 623 communicates with at least one of the plurality of first tributary channels 621. A plurality of fourth tributary channels 624 are provided in a portion of the third main channel 613 on the second main channel 612 side. At least one of the plurality of fourth tributary channels 624 communicates with at least one of the plurality of second tributary channels 622.

[0051] The first circulation port 55 is arranged on the first side surface 51 in a range from half the length from the center 51C of the first side surface 51 to the third side surface 53. In other words, when the length from the center 51C of the first side surface 51 to the third side surface 53 is defined as 1, the first circulation port 55 is arranged at a position in a range of 0.5 to 1 from the center 51C toward the third side surface 53. The first circulation port 55 communicates between the outside of the housing 5 and the first main flow path 611. A refrigerant can flow through the first circulation port 55. The second circulation port 56 is arranged on the first side surface 51 in a range from half the length from the center 51C of the first side surface 51 to the fourth side surface 54. In other words, when the length from the center 51C of the first side surface 51 to the fourth side surface 54 is defined as 1, the second circulation port 56 is arranged at a position in a range from 0.5 to 1 toward the fourth side surface 54 from the center 51C. The second circulation port 56 communicates between the outside of the housing 5 and the second main flow path 612. A refrigerant can flow through the second circulation port 56. The third flow port 57 is disposed on the second side surface. The third flow port 57 connects the outside of the housing 5 with the third main flow path 613. The third flow port 57 allows the refrigerant to flow through.

[0052] According to this configuration, for example, if the first circulation port 55 and the second circulation port 56 are configured as inlet ports for circulating the refrigerant within the storage chamber 6, and the third circulation port 57 is configured as an outlet port for discharging the refrigerant that has circulated within the storage chamber 6, the refrigerant will circulate within the storage chamber 6 from the first circulation port 55 and the second circulation port 56 toward the third circulation port 57. Here, in order to improve the heat exchange efficiency of the heat exchanger 4, it is considered to reduce the flow resistance within the accommodating chamber 6 and reduce the pressure loss of the refrigerant. In order to reduce the flow resistance of the first main flow path 611 into which the refrigerant flows from the first flow port 55, it is preferable that the first main flow path 611 extend in a substantially straight line. However, when the first flow port 55 is provided near the center 51C of the first side surface 51, attempting to extend the first main flow path 611 in a straight line makes it difficult to arrange the first main flow path 611 at the intersection between the first side surface 51 and the third side surface 53. On the other hand, if the first main flow path 611 is extended from the first flow port 55 provided near the center 51C of the first side surface 51 toward the intersection between the first side surface 51 and the third side surface 53 and then extended along the third side surface 53, the first main flow path 611 will be bent. In such a case, the flow resistance of the first main flow path 611 increases, resulting in a large pressure loss of the refrigerant.

[0053] In contrast, in heat exchangers 41, 42, and 43, first flow ports 55 are arranged in first side surface 51 in a range from half the length from center 51C of first side surface 51 to third side surface 53 to third side surface 53. Therefore, even if first main flow path 611 is extended to the intersection of first side surface 51 and third side surface 53 and then extended along third side surface 53, it is possible to prevent first main flow path 611 from bending significantly. This not only makes it possible to arrange first main flow path 611 at the intersection of first side surface 51 and third side surface 53, but also reduces the flow path resistance of first main flow path 611 and reduces pressure loss of the refrigerant. Similarly, in heat exchangers 41, 42, and 43, second flow ports 56 are arranged in first side surface 51 in a range from half the length from center 51C of first side surface 51 to fourth side surface 54 to fourth side surface 54. Therefore, even if second main flow path 612 is extended to the intersection of first side surface 51 and fourth side surface 54 and then extended along fourth side surface 54, it is possible to prevent second main flow path 612 from bending significantly. This not only makes it possible to arrange second main flow path 612 at the intersection of first side surface 51 and fourth side surface 54, but also reduces flow path resistance of second main flow path 612 and reduces pressure loss of the refrigerant.

[0054] In this way, it is possible to arrange flow paths at the intersection of the first side surface 51 and the third side surface 53 and at the intersection of the first side surface 51 and the fourth side surface, and it is also possible to prevent the flow path resistance of the first main flow path 611 and the flow path resistance of the second main flow path 612 from increasing, thereby preventing an increase in pressure loss of the refrigerant. Therefore, it is possible to improve the heat exchange efficiency between the heat exchangers 41, 42, 43 and the refrigerant. Furthermore, the cooling device 3 equipped with the heat exchangers 41, 42, and 43 can be configured as a cooling device with high cooling efficiency for heat-generating elements. This increases the cooling efficiency for the light source 21, so that even if the amount of light incident from the light source 21 to the light modulation element 23 is increased, the temperature rise of the light source 21 can be suppressed, making it possible to configure a projector 1 that can project high-brightness image light. In other words, since the cooling efficiency for heat-generating elements can be increased, it is possible to configure an electronic device that can operate stably.

[0055] In the heat exchanger 4 including the heat exchangers 41 to 43, the flow path cross-sectional area of ​​the first branch flow path 621 is smaller than the flow path cross-sectional area of ​​the first main flow path 611. The flow path cross-sectional area of ​​the second branch flow path 622 is smaller than the flow path cross-sectional area of ​​the second main flow path 612. The flow path cross-sectional areas of the third branch flow path 623 and the fourth branch flow path 624 are each smaller than the flow path cross-sectional area of ​​the third main flow path 613. According to this configuration, a larger number of first tributary channels 621 can be provided in the first main channel 611, and a larger number of second tributary channels 622 can be provided in the second main channel 612. Similarly, a larger number of third tributary channels 623 can be provided in the third main channel 613, and a larger number of fourth tributary channels 624 can be provided in the third main channel 613. Therefore, the contact area with the refrigerant in the accommodation chamber 6 can be increased, and the heat exchange efficiency of the heat exchanger 4 can be improved.

[0056] The heat exchanger 4 including the heat exchangers 41 to 43 includes a plurality of first tributary channels 631 and a plurality of second tributary channels 632 . The cross-sectional area of ​​each of the plurality of first tributary channels 631 is smaller than the cross-sectional area of ​​the first tributary channel 621 and the cross-sectional area of ​​the third tributary channel 623. At least one of the plurality of first tributary channels 631 connects the first tributary channel 621 and the third tributary channel 623. The cross-sectional area of ​​each of the plurality of second tributary channels 632 is smaller than the cross-sectional area of ​​the second tributary channel 622 and the cross-sectional area of ​​the fourth tributary channel 624. At least one second tributary channel 632 among the plurality of second tributary channels 632 connects the second tributary channel 622 and the fourth tributary channel 624. According to this configuration, the surface area of ​​the flow path can be increased throughout the entire accommodating chamber 6, which in turn increases the contact area with the refrigerant in the accommodating chamber 6 and also suppresses an increase in pressure loss, thereby improving the heat exchange efficiency of the heat exchanger 4.

[0057] In the heat exchangers 41, 42, the first flow port 55 is positioned away from the center 51C of the first side surface 51 toward the third side surface 53 by a length of 0.75 or more and 1 or less, where 1 is the length from the center 51C of the first side surface 51 to the third side surface 53. In the heat exchangers 41, 42, the second flow port 56 is positioned away from the center 51C of the first side surface 51 toward the fourth side surface 54 by a length of 0.75 or more and 1 or less, where 1 is the length from the center 51C of the first side surface 51 to the fourth side surface 54. With this configuration, the first main flow path 611 can be disposed at the intersection of the first side surface 51 and the third side surface 53, and the second main flow path 612 can be disposed at the intersection of the first side surface 51 and the fourth side surface 54. Furthermore, the first main flow path 611 and the second main flow path 612 can each extend in a substantially straight line. This reduces the flow path resistance of each main flow path 611, 612 and further increases the contact area with the refrigerant in the storage chamber. Therefore, the heat exchange efficiency of the heat exchangers 41, 42 can be further improved.

[0058] [Second embodiment] Next, a second embodiment of the present disclosure will be described. The projector according to this embodiment has a similar configuration to the projector 1 according to the first embodiment, but differs in the configuration of the heat exchanger that constitutes the cooling device 3. More specifically, the heat exchanger for the gas in this embodiment further includes a fourth circulation port and a fourth main flow path. Note that in the following explanation, parts that are the same or approximately the same as parts already explained will be assigned the same reference numerals and explanations thereof will be omitted.

[0059] [Projector configuration] Fig. 8 is a cross-sectional view showing the internal configuration of a heat exchanger 7 included in a cooling device of a projector according to this embodiment. Specifically, Fig. 8 is a cross-sectional view showing the internal configuration of a heat exchanger 72 of the heat exchanger 7. The heat exchanger 7 has a first circulation port 55 located 0.75 away from the center 51C of the first side surface 51 toward the third side surface 53, where 1 is the distance from the center 51C to the third side surface 53; a second circulation port 56 located 0.75 away from the center 51C toward the fourth side surface 54, where 1 is the distance from the center 51C to the fourth side surface 54; and a fourth circulation port 58 located at the center 51C of the first side surface 51. In Fig. 8, only some of the multiple first tributary channels 621 are labeled with reference numerals. The same applies to the second tributary channel 622, the third tributary channel 623, the fourth tributary channel 624, the first narrow tributary channel 631, and the second narrow tributary channel 632. The projector according to this embodiment has the same configuration and functions as the projector 1 according to the first embodiment, except that it has a heat exchanger 7 shown in FIG. 8 instead of the heat exchanger 4. That is, the cooling device according to this embodiment has the same configuration and functions as the cooling device 3 according to the first embodiment, except that it has a heat exchanger 7 instead of the heat exchanger 4. That is, the cooling device according to this embodiment has a plurality of heat exchangers 7. Although not shown in the figures, the plurality of heat exchangers 7 include a red heat exchanger connected to the heat receiving plate 22R so as to be heat transferable, a green heat exchanger connected to the heat receiving plate 22G so as to be heat transferable, and a blue heat exchanger connected to the heat receiving plate 22B so as to be heat transferable.

[0060] [Heat exchanger configuration] The heat exchanger 7 is a cold plate that cools a heat-generating element by transferring heat received from the heat-generating element to a refrigerant flowing therethrough. The heat exchanger 7 has the same configuration and function as the heat exchanger 4 according to the first embodiment, except that it further includes a fourth flow port 58 and a fourth main flow path 614. That is, the heat exchanger 7 includes a housing 5 in which an accommodation chamber 6 is provided, a first flow port 55, a second flow port 56, a third flow port 57, a fourth flow port 58, a first main flow path 611, a second main flow path 612, a third main flow path 613, a fourth main flow path 614, branch flow paths 621, 622, 623, 624, and narrow branch flow paths 631, 632.

[0061] The fourth flow port 58 is disposed at the center 51C of the first side surface 51 of the housing 5. The fourth flow port 58 connects the outside of the housing 5 with the inside of the storage chamber 6. The fourth flow port 58 allows the refrigerant circulating in the cooling device to flow therethrough. The fourth main flow path 614 extends from the fourth flow port 58 toward the second side surface 52 and communicates with each of the third branch flow path 623 and the fourth branch flow path 624. The flow path cross-sectional area of ​​the fourth main flow path 614 is smaller than the flow path cross-sectional area of ​​the third main flow path 613 on the third flow port 57 side.

[0062] In the heat exchanger 7, the third main flow path 613 is made up of a first partial flow path 6131, a second partial flow path 6132, and a third partial flow path 6133. The first partial flow path 6131 extends from the second side surface 52 toward the first side surface 51, is a flow path through which a refrigerant can flow, and is connected to the third flow port 57. The first partial flow path 6131 extends from the second side surface 52 by a length that is approximately one-third of the distance from the second side surface 52 to the first side surface 51. The flow path cross-sectional area of ​​the first partial flow path 6131 is approximately constant on the X-axis. The second partial channel 6132 extends from the first partial channel 6131 toward the first side surface 51 between the first main channel 611 and the fourth main channel 614. The cross-sectional area of ​​the second partial channel 6132 decreases toward the first side surface 51. The third partial channel 6133 extends from the first partial channel 6131 toward the first side surface 51 between the second main channel 612 and the fourth main channel 614. The cross-sectional area of ​​the third partial channel 6133 decreases toward the first side surface 51.

[0063] Furthermore, in the heat exchanger 7, the multiple third branch channels 623 extend from portions of the first partial channel 6131 and the second partial channel 6132 constituting the third main channel 613 on the first main channel 611 side toward the first main channel 611, and also extend from portions of the third partial channel 6133 on the fourth main channel 614 side toward the fourth main channel 614. Therefore, the multiple third branch channels 623 extending from portions of the third partial channel 6133 on the fourth main channel 614 side communicate with a portion of the fourth main channel 614 on the third partial channel 6133 side. Similarly, in the heat exchanger 7, the multiple fourth branch channels 624 extend from portions of the first partial channel 6131 and the third partial channel 6133 constituting the third main channel 613 on the second main channel 612 side toward the second main channel 612, and also extend from portions of the second partial channel 6132 on the fourth main channel 614 side toward the fourth main channel 614. Therefore, the multiple fourth branch channels 624 extending from portions of the second partial channel 6132 on the fourth main channel 614 side communicate with a portion of the fourth main channel 614 on the second partial channel 6132 side.

[0064] [Refrigerant circulation path in the storage chamber] In such heat exchanger 7, when the flow ports 55, 56, and 58 are used as refrigerant inlet ports and the flow port 57 is used as a refrigerant outlet port, the refrigerant flows through the first main flow path 611, the second main flow path 612, and the fourth main flow path 614. The refrigerant that has circulated through the first main flow path 611 flows to the first partial flow path 6131 or the second partial flow path 6132 of the third main flow path 613 via at least one of the first branch flow path 621, the first narrow branch flow path 631, and the third branch flow path 623. The refrigerant that has circulated through the second main flow path 612 flows to the first partial flow path 6131 or the third partial flow path 6133 of the third main flow path 613 via at least one of the second branch flow path 622, the second narrow branch flow path 632, and the fourth branch flow path 624. The refrigerant that has flowed through the fourth main flow path 614 flows through the fourth branch flow path 624 to the second partial flow path 6132 , and also flows through the third branch flow path 623 to the third partial flow path 6133 . In this way, by having the refrigerant flow through the plurality of branch channels and the plurality of narrow branch channels formed in the accommodation chamber 6, the heat transferred to the heat exchanger 7 can be easily transferred to the refrigerant. If the flow port 57 is used as an inlet for the refrigerant and the flow ports 55, 56, 58 are used as outlets for the refrigerant, the refrigerant will flow in the opposite direction to the above.

[0065] [Heat exchange efficiency of heat exchanger] Similar to the heat exchanger 4 according to the first embodiment, a heat exchanger can be configured in which the distances from the center 51C of the first side surface 51 to the first circulation ports 55 and the second circulation ports 56 are different. For example, the heat exchanger 7 shown in Figure 8 is a heat exchanger 72 having a first circulation port 55 located at a position 0.75 away from the center 51C toward the third side surface 53 when the distance from the center 51C of the first side surface 51 to the third side surface 53 is 1, a second circulation port 56 located at a position 0.75 away from the center 51C toward the fourth side surface 54 when the distance from the center 51C of the first side surface 51 to the fourth side surface 54 is 1, and a fourth circulation port 58 located at the center 51C of the first side surface 51.

[0066] FIG. 9 is a graph showing the heat transfer efficiency of the heat exchanger 7 to the refrigerant. The heat exchange efficiency of the heat exchanger 7 changes depending on the positions of the first circulation port 55 and the second circulation port 56 on the first side surface 51. The inventors of the present disclosure investigated the heat transfer efficiency to the refrigerant using heat exchangers 7 in which the distances of first and second flow ports 55 and 56 from center 51C of first side surface 51 were varied, similar to the heat exchangers 41 to 45 described above. As a result, as shown in Fig. 9, it was found that in heat exchangers 7 in which first and second flow ports 55 and 56 were arranged at positions that were 0.5 to 1 degree away from center 51C of first side surface 51, the heat transfer efficiency to the refrigerant was relatively high, whereas in heat exchangers 7 in which first and second flow ports 55 and 56 were arranged at positions that were 0 to less than 0.5 degree away from center 51C of first side surface 51, the heat transfer efficiency to the refrigerant was relatively low. Furthermore, it was found that the heat transfer efficiency to the refrigerant of the heat exchanger 7 in which the flow ports 55, 56 are arranged at a position that is 0.75 or more and 1 or less away from the center 51C of the first side surface 51 is higher than the heat transfer efficiency to the refrigerant of the other heat exchangers 7, and that the heat transfer efficiency to the refrigerant of the heat exchanger 72 in which the flow ports 55, 56 are arranged at a position that is 0.75 away from the center 51C of the first side surface 51 is the highest. The reason why the heat transfer efficiency of the heat exchanger 7 to the refrigerant, i.e., the heat exchange efficiency of the heat exchanger 7, differs depending on the positions of the first flow port 55 and the second flow port 56 is thought to be the same as the reason shown in the first embodiment.

[0067] For the above reasons, the cooling device according to this embodiment preferably employs a heat exchanger 7 having a first flow port 55 disposed at a distance of 0.5 to 1 from the center 51C of the first side surface 51 toward the third side surface 53, where 1 is the length from the center 51C of the first side surface 51 to the third side surface 53, and a second flow port 56 disposed at a distance of 0.5 to 1 from the center 51C of the first side surface 51 toward the fourth side surface 54, where 1 is the length from the center 51C of the first side surface 51 to the fourth side surface 54. Furthermore, the cooling device according to this embodiment preferably employs a heat exchanger 7 having a first flow port 55 disposed at a distance of 0.75 to 1 from the center 51C of the first side surface 51 toward the third side surface 53, and a second flow port 56 disposed at a distance of 0.75 to 1 from the center 51C of the first side surface 51 toward the fourth side surface 54. An example of such a heat exchanger 7 is the heat exchanger 72 described above.

[0068] [Effects of the second embodiment] The projector according to this embodiment described above has the same effects as the projector 1 according to the first embodiment, and also has the following effects. In addition to the configuration of the heat exchanger 4, the heat exchanger 7 includes a fourth flow port 58 and a fourth main flow path 614. The fourth flow port 58 is disposed at the center 51C of the first side surface 51, and connects the outside of the housing 5 with the inside of the accommodation chamber 6. The fourth flow port 58 allows a refrigerant to flow through it. The fourth main flow path 614 extends from the fourth flow port 58 toward the second side surface 52 and communicates with each of the third branch flow path 623 and the fourth branch flow path 624. The flow path cross-sectional area of ​​the fourth main flow path 614 is smaller than the flow path cross-sectional area of ​​the third main flow path 613 on the third flow port 57 side. This configuration can increase the flow rate of the refrigerant circulating in the heat exchanger 7. In addition, because the cross-sectional area of ​​the fourth main flow path 614 extending from the fourth flow port 58 is smaller than the cross-sectional area of ​​the third main flow path 613, the surface area of ​​the flow path can be increased throughout the entire storage chamber 6, and therefore the contact area with the refrigerant in the storage chamber 6 can be expanded. Therefore, the heat exchange efficiency of the heat exchanger 7 can be improved.

[0069] In the heat exchanger 7, the third main flow path 613 includes a first partial flow path 6131, a second partial flow path 6132, and a third partial flow path 6133. The first partial flow path 6131 communicates with the third flow port 57 . The second partial channel 6132 extends from the first partial channel 6131 between the first main channel 611 and the fourth main channel 614 . The third partial channel 6133 extends from the first partial channel 6131 between the second main channel 612 and the fourth main channel 614 . With this configuration, the refrigerant can circulate between the first main flow path 611 and the fourth main flow path 614 and the third main flow path 613, and also between the second main flow path 612 and the fourth main flow path 614 and the third main flow path 613. Therefore, when one of the first flow port 55, the second flow port 56, the fourth flow port 58, and the third flow port 57 is an inlet for introducing the refrigerant into the storage chamber 6 and the other is an outlet for discharging the refrigerant that has circulated within the storage chamber 6, the refrigerant can be easily circulated within the storage chamber 6. Therefore, the heat exchange efficiency of the heat exchanger 7 can be improved.

[0070] [Modification of the embodiment] The present disclosure is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present disclosure are included in the present disclosure. In the first embodiment, the heat exchanger 4 has the first flow port 55 and the second flow port 56 provided in the first side surface 51, and one third flow port 57 provided in the second side surface 52. In the second embodiment, the heat exchanger 7 has the first flow port 55, the second flow port 56, and the fourth flow port 58 provided in the first side surface 51, and the third flow port 57 provided in the second side surface 52. However, this is not limited thereto, and the number of flow ports provided in the first side surface 51 may be four or more, and the number of flow ports provided in the second side surface 52 may be two or more.

[0071] In each of the above embodiments, the third flow port 57 is disposed at the center 52C of the second side surface 52 in the Y axis, and the third main flow path 613, which communicates with the outside of the housing 5 via the third flow port 57, passes through the center of the storage chamber 6 when viewed from the +Z direction. However, this is not limiting, and the third flow port 57 may be shifted from the center 52C on the second side surface 52 toward the third side surface 53 or the fourth side surface 54. Furthermore, the third main flow path 613 may not pass through the center of the storage chamber 6, but may be disposed biased toward the third side surface 53 or the fourth side surface 54.

[0072] In each of the above-described embodiments, the heat exchangers 4 and 7 include a plurality of first tributary channels 631 and a plurality of second tributary channels 632. However, this is not limiting, and at least one of the first tributary channels 631 and the second tributary channels 632 may be omitted. Furthermore, at least one of the plurality of first narrow tributary channels 631 is configured to connect the first tributary channel 621 to the third tributary channel 623. However, this is not limiting, and each of the plurality of first narrow tributary channels 631 provided in the first tributary channel 621 may be connected to the third main channel 613, and each of the plurality of first narrow tributary channels 631 provided in the third tributary channel 623 may be connected to the first main channel 611. The same applies to the second narrow tributary channels 632.

[0073] In each of the above embodiments, the cooling device 3 includes the heat exchangers 4 and 7, the reservoir 31, the radiator 32, the pump 33, and the piping 34. However, this is not limiting, and the reservoir 31 may be omitted, and the configuration of the cooling device of the present disclosure is not limited to the above. Furthermore, in each of the above embodiments, the refrigerant flowing through the heat exchangers 4 and 7 is a liquid refrigerant, but this is not limitative and the refrigerant may be a gaseous refrigerant.

[0074] In the first embodiment, the cooling device 3 includes a plurality of heat exchangers 4, including the red heat exchanger 4R, the green heat exchanger 4G, and the blue heat exchanger 4B. However, the number of heat exchangers 4 included in the cooling device 3 can be changed as appropriate. The same applies to the cooling device according to the second embodiment. In the first embodiment, the refrigerant discharged from the pump 33 flows through the blue heat exchanger 4B, the green heat exchanger 4G, and the red heat exchanger 4R in this order. However, this is not limiting, and the flow order of the refrigerant through the multiple heat exchangers can be changed as appropriate. Furthermore, the refrigerant discharged from the pump 33 may be divided by the pipe 34 and flow in parallel through the blue heat exchanger 4B, the green heat exchanger 4G, and the red heat exchanger 4R. The same applies to the cooling device according to the second embodiment.

[0075] In the above embodiments, the heat exchangers 4, 7 are connected to the heat receiving plate 22, which is connected to the light source 21, which is a heat generating element, in a heat transferable manner. That is, the heat exchangers 4, 7 are intended to cool the light source 21, which is a heat generating element. However, this is not limiting, and the heat receiving plate 22 may be connected to another heat generating element, and the heat exchanger 4, 7 may cool another heat generating element. For example, the heat receiving plate 22 may be provided on the light modulation element 23, and the heat exchangers 4, 7 may be connected to the heat receiving plate 22 provided on the light modulation element 23 in a heat transferable manner. Furthermore, depending on the configuration of the heat generating element to be cooled, the heat receiving plate 22 may be omitted.

[0076] In each of the above embodiments, the projector 1 includes three light modulation elements 23R, 23G, and 23B. However, the present disclosure is not limited to this and can also be applied to a projector including two or less light modulation elements, or four or more light modulation elements.

[0077] In each of the above embodiments, the light modulation element 23 includes a transmissive liquid crystal panel having different light incident and light exit surfaces. However, the present invention is not limited to this, and the light modulation element may include a reflective liquid crystal panel having the same light incident and light exit surfaces. Furthermore, as long as the light modulation device is capable of modulating an incident light beam to form an image according to image information, a light modulation element other than a liquid crystal may be used, such as a device using a micromirror, for example, a DMD (Digital Micromirror Device).

[0078] In each of the above embodiments, light source 21 includes red light source 21R, green light source 21G, and blue light source 21B, and each of light sources 21R, 21G, and 21B includes a light-emitting element. However, the present invention is not limited to this. Light source 21 may include a light-emitting element and a wavelength conversion element that converts the wavelength of light emitted from the light-emitting element, or may include a discharge light source lamp such as an ultra-high pressure mercury lamp. In other words, the configuration of the light source is not limited.

[0079] In the above embodiments, an example was given in which the cooling device 3 including the heat exchangers 4 and 7 was applied to a projector. However, this is not limiting, and the cooling device including the heat exchangers 4 and 7 may be applied to electronic devices other than projectors. For example, the heat exchanger of the present disclosure may be used to cool integrated circuits included in electronic devices.

[0080] Summary of this disclosure A summary of this disclosure is provided below. [Appendix 1] a housing having a first side surface and a second side surface located opposite to each other, a third side surface and a fourth side surface that intersect with the first side surface and the second side surface and are located opposite to each other, and a storage chamber surrounded by the first side surface, the second side surface, the third side surface, and the fourth side surface; a first main flow path extending within the accommodation chamber along the third side surface toward the second side surface; a second main flow path extending within the accommodation chamber along the fourth side surface toward the second side surface; a third main flow path provided between the first main flow path and the second main flow path within the accommodation chamber and extending toward the first side surface; a plurality of first branch channels provided at a plurality of locations on the first main channel and branching off from the first main channel; a plurality of second branch channels provided at a plurality of locations on the second main channel and branching from the second main channel; a plurality of third tributary channels provided in a portion of the third main channel on the side of the first main channel, the third tributary channels communicating with at least one of the plurality of first tributary channels; a plurality of fourth branch channels provided in a portion of the third main channel on the second main channel side, the fourth branch channels communicating with at least one of the plurality of second branch channels; a first flow port that is arranged in the first side surface in a range from halfway along a length from a center of the first side surface to the third side surface and that connects the outside of the housing with the first main flow path and through which a coolant can flow; a second flow port that is arranged in the first side surface in a range from halfway along a length from a center of the first side surface to the fourth side surface to the fourth side surface, that connects the outside of the housing with the second main flow path and through which a coolant can flow; a third flow port that is disposed on the second side surface, that connects the outside of the housing with the third main flow path, and through which a coolant can flow; A heat exchanger characterized by:

[0081] According to this configuration, for example, if the first and second circulation ports are configured as inlet ports for circulating the refrigerant within the storage chamber, and the third circulation port is configured as an outlet port for discharging the refrigerant that has circulated within the storage chamber, the refrigerant will circulate within the storage chamber from the first and second circulation ports toward the third circulation port. Here, in order to improve the heat exchange efficiency of the heat exchanger, it is considered to reduce the flow resistance within the accommodating chamber and thereby reduce the pressure loss of the refrigerant. To reduce the flow resistance of the first main flow path into which the refrigerant flows from the first flow port, it is preferable that the first main flow path extend in a substantially straight line. However, when the first flow port is provided near the center of the first side surface, extending the first main flow path in a straight line makes it difficult to arrange the first main flow path at the intersection between the first side surface and the third side surface. On the other hand, if the first main flow path is extended from the first flow port provided near the center of the first side surface toward the intersection between the first side surface and the third side surface and then extended along the third side surface, the first main flow path will bend. In such a case, the flow resistance of the first main flow path increases, resulting in a large pressure loss of the refrigerant.

[0082] In contrast, the first flow port is disposed in the first side surface in a range from halfway along the length from the center of the first side surface to the third side surface to the third side surface. Therefore, even if the first main flow path is extended to the intersection of the first side surface and the third side surface and then extended along the third side surface, it is possible to prevent the first main flow path from bending significantly. This not only allows the first main flow path to be disposed at the intersection of the first side surface and the third side surface, but also reduces the flow path resistance of the first main flow path. Similarly, the second flow ports are arranged in the first side surface in a range from halfway along the length from the center of the first side surface to the fourth side surface to the fourth side surface. Therefore, even if the second main flow path is extended to the intersection of the first side surface and the fourth side surface and then extended along the fourth side surface, the second main flow path can be prevented from bending significantly. This not only allows the second main flow path to be arranged at the intersection of the first side surface and the fourth side surface, but also reduces the flow path resistance of the second main flow path and the pressure loss of the refrigerant. In this way, the flow paths can be arranged at the intersections of the first and third side faces and the first and fourth side faces, and the flow path resistances of the first and second main flow paths can be prevented from increasing, thereby preventing an increase in refrigerant pressure loss, thereby improving the heat exchange efficiency between the heat exchanger and the refrigerant.

[0083] [Appendix 2] 2. The heat exchanger according to claim 1, a flow path cross-sectional area of ​​the first branch flow path is smaller than a flow path cross-sectional area of ​​the first main flow path, a flow path cross-sectional area of ​​the second branch flow path is smaller than a flow path cross-sectional area of ​​the second main flow path, a flow path cross-sectional area of ​​the third branch flow path and a flow path cross-sectional area of ​​the fourth branch flow path are each smaller than a flow path cross-sectional area of ​​the third main flow path; A heat exchanger characterized by: With this configuration, a larger number of first branch channels can be provided in the first main channel, and a larger number of second branch channels can be provided in the second main channel. Similarly, a larger number of third branch channels can be provided in the third main channel, and a larger number of fourth branch channels can be provided in the third main channel. Therefore, the contact area between the refrigerant and the accommodation chamber can be increased, thereby improving the heat exchange efficiency of the heat exchanger.

[0084] [Appendix 3] 3. The heat exchanger according to claim 2, a plurality of first tributary channels each having a cross-sectional area smaller than a cross-sectional area of ​​the first tributary channel and a cross-sectional area of ​​the third tributary channel; a plurality of second tributary channels each having a cross-sectional area smaller than a cross-sectional area of ​​the second tributary channel and a cross-sectional area of ​​the fourth tributary channel, At least one of the plurality of first tributary channels communicates the first tributary channel with the third tributary channel, At least one second tributary channel among the plurality of second tributary channels communicates the second tributary channel with the fourth tributary channel. A heat exchanger characterized by: This configuration increases the surface area of ​​the flow path throughout the entire chamber, thereby increasing the contact area with the refrigerant in the chamber and suppressing an increase in pressure loss, thereby improving the heat exchange efficiency of the heat exchanger.

[0085] [Appendix 4] 4. The heat exchanger according to claim 1, a fourth flow port that is disposed at the center of the first side surface, communicates with the storage chamber, and allows a refrigerant to flow therethrough; a fourth main flow path having a flow path cross-sectional area smaller than a flow path cross-sectional area of ​​the third main flow path on the third flow port side, extending from the fourth flow port toward the second side surface and communicating with each of the third branch flow path and the fourth branch flow path, A heat exchanger characterized by: This configuration increases the flow rate of the refrigerant flowing through the heat exchanger. Furthermore, because the cross-sectional area of ​​the fourth main flow path extending from the fourth flow port is smaller than the cross-sectional area of ​​the third main flow path, the surface area of ​​the flow path can be increased throughout the accommodating chamber, thereby increasing the contact area with the refrigerant in the accommodating chamber. This increases the heat exchange efficiency of the heat exchanger.

[0086] [Appendix 5] 5. The heat exchanger according to claim 4, The third main flow path is a first partial flow path communicating with the third flow port; a second partial flow path extending from the first partial flow path between the first main flow path and the fourth main flow path; a third partial flow path extending from the first partial flow path between the second main flow path and the fourth main flow path, A heat exchanger characterized by: This configuration allows the refrigerant to flow between the first and fourth main flow paths and the third main flow path, as well as between the second and fourth main flow paths and the third main flow path. Therefore, when one of the first, second, and fourth flow paths and the third flow path is an inlet for introducing the refrigerant into the accommodating chamber and the other is an outlet for discharging the refrigerant that has flowed through the accommodating chamber, the refrigerant can be easily circulated within the accommodating chamber. This improves the heat exchange efficiency of the heat exchanger.

[0087] [Appendix 6] 6. The heat exchanger according to claim 1, the first flow port is disposed away from the center of the first side surface toward the third side surface by a length of 0.75 to 1, where 1 is the length from the center of the first side surface to the third side surface, When the length from the center of the first side surface to the fourth side surface is 1, the second flow port is disposed away from the center of the first side surface toward the fourth side surface by a length of 0.75 to 1. A heat exchanger characterized by: With this configuration, the first main flow path can be located at the intersection of the first and third side faces, and the second main flow path can be located at the intersection of the first and fourth side faces. Furthermore, the first and second main flow paths can each extend in a substantially straight line. This reduces the flow path resistance of each main flow path and further increases the contact area with the refrigerant in the storage chamber. This further increases the heat exchange efficiency of the heat exchanger.

[0088] [Appendix 7] A heat exchanger according to any one of claims 1 to 6; a radiator that radiates heat received by the refrigerant in the heat exchanger; a pump that circulates the refrigerant between the heat exchanger and the radiator, A cooling device characterized by: With this configuration, it is possible to achieve the same effect as the heat exchanger described above, and to configure a cooling device that has high cooling efficiency for an object to be cooled.

[0089] [Appendix 8] a cooling device according to claim 7; A light source and a light modulation element that modulates the light emitted from the light source; a projection optical device that projects the modulated light; a heat receiving plate provided on one of the heat generating elements of the light source and the light modulation element, The heat exchanger of the cooling device is connected to the heat receiving plate so as to be capable of transferring heat. A projector characterized by: This configuration can improve the cooling efficiency of the heat generating element of either the light source or the image forming panel, thereby suppressing the temperature rise of the heat generating element even when the amount of light incident on the light modulation element from the light source is increased, thereby enabling the construction of a projector capable of projecting high-brightness image light.

[0090] [Appendix 9] a cooling device according to claim 7; a heating element having a heat receiving plate, The heat exchanger of the cooling device is connected to the heat receiving plate so as to be capable of conducting heat therethrough. An electronic device characterized by: According to this configuration, the cooling efficiency of the heat generating element can be improved, and therefore an electronic device that can operate stably can be configured. [Explanation of symbols]

[0091] 1...projector, 2...image projection device, 21...light source, 21B...blue light source, 21G...green light source, 21R...red light source, 22, 22B, 22G, 22R...heat receiving plate, 23...light modulation element, 23B...blue light modulation element, 23G...green light modulation element, 23R...red light modulation element, 24...color combining element, 25...projection optical device, 3...cooling device, 31...reservoir, 32...heat sink, 33...pump, 34...piping, 4, 41, 42, 43, 44, 45, 7, 72...heat exchanger, 4B...heat exchanger for blue, 4G...green Heat exchanger for red air, 4R...heat exchanger for red air, 5...housing, 51...first side, 51C...center, 52...second side, 52C...center, 53...third side, 54...fourth side, 55...first circulation port, 56...second circulation port, 57...third circulation port, 58...fourth circulation port, 6...storage chamber, 611...first main flow path, 612...second main flow path, 613...third main flow path, 614...fourth main flow path, 621...first branch flow path, 622...second branch flow path, 623...third branch flow path, 624...fourth branch flow path, 631...first narrow branch flow path, 632...second narrow branch flow path.

Claims

1. a housing having a first side surface and a second side surface located opposite to each other, a third side surface and a fourth side surface that intersect the first side surface and the second side surface and are located opposite to each other, and a storage chamber surrounded by the first side surface, the second side surface, the third side surface, and the fourth side surface; a first main flow path extending within the accommodation chamber along the third side surface toward the second side surface; a second main flow path extending within the accommodation chamber along the fourth side surface toward the second side surface; a third main flow path provided in the accommodation chamber between the first main flow path and the second main flow path and extending toward the first side surface; a plurality of first branch channels provided at a plurality of locations on the first main channel and branching from the first main channel; a plurality of second branch channels provided at a plurality of locations on the second main channel and branching from the second main channel; a plurality of third tributary channels provided in a portion of the third main channel on the side of the first main channel, the third tributary channels communicating with at least one of the plurality of first tributary channels; a plurality of fourth branch channels provided in a portion of the third main channel on the second main channel side, the fourth branch channels communicating with at least one of the plurality of second branch channels; a first flow port that is arranged in the first side surface in a range from halfway along a length from a center of the first side surface to the third side surface and that connects the outside of the housing with the first main flow path and through which a coolant can flow; a second flow port that is disposed in the first side surface in a range from halfway along a length from a center of the first side surface to the fourth side surface to the fourth side surface, the second flow port communicating the outside of the housing with the second main flow path and allowing a refrigerant to flow; a third flow port that is disposed on the second side surface, that connects the outside of the housing with the third main flow path, and through which the coolant can flow; A heat exchanger characterized by:

2. 2. The heat exchanger according to claim 1, a flow path cross-sectional area of ​​the first branch flow path is smaller than a flow path cross-sectional area of ​​the first main flow path, a flow path cross-sectional area of ​​the second branch flow path is smaller than a flow path cross-sectional area of ​​the second main flow path, a flow path cross-sectional area of ​​the third branch flow path and a flow path cross-sectional area of ​​the fourth branch flow path are each smaller than a flow path cross-sectional area of ​​the third main flow path; A heat exchanger characterized by:

3. 3. The heat exchanger according to claim 2, a plurality of first tributary channels each having a cross-sectional area smaller than a cross-sectional area of ​​the first tributary channel and a cross-sectional area of ​​the third tributary channel; a plurality of second tributary channels each having a cross-sectional area smaller than a cross-sectional area of ​​the second tributary channel and a cross-sectional area of ​​the fourth tributary channel, At least one first tributary channel among the plurality of first tributary channels communicates the first tributary channel with the third tributary channel, At least one second tributary channel among the plurality of second tributary channels communicates the second tributary channel with the fourth tributary channel. A heat exchanger characterized by:

4. 2. The heat exchanger according to claim 1, a fourth flow port that is disposed at the center of the first side surface, that communicates with the storage chamber, and through which a refrigerant can flow; a fourth main flow path having a flow path cross-sectional area smaller than a flow path cross-sectional area of ​​the third main flow path on the third flow port side, extending from the fourth flow port toward the second side surface and communicating with each of the third branch flow path and the fourth branch flow path, A heat exchanger characterized by:

5. 5. The heat exchanger according to claim 4, The third main flow path is a first partial flow path communicating with the third flow port; a second partial flow path extending from the first partial flow path between the first main flow path and the fourth main flow path; a third partial flow path extending from the first partial flow path between the second main flow path and the fourth main flow path, A heat exchanger characterized by:

6. The heat exchanger according to any one of claims 1 to 5, the first flow port is disposed away from the center of the first side surface toward the third side surface by a length of 0.75 to 1, where 1 is the length from the center of the first side surface to the third side surface, the second flow port is disposed away from the center of the first side surface toward the fourth side surface by a length of 0.75 to 1, where 1 is the length from the center of the first side surface to the fourth side surface, A heat exchanger characterized by:

7. The heat exchanger according to any one of claims 1 to 5; a radiator that radiates heat received by the refrigerant in the heat exchanger; a pump that circulates the refrigerant between the heat exchanger and the radiator, A cooling device characterized by:

8. The cooling device according to claim 7; A light source and a light modulation element that modulates the light emitted from the light source; a projection optical device that projects the modulated light; a heat receiving plate provided on one of the heat generating elements of the light source and the light modulation element, The heat exchanger of the cooling device is connected to the heat receiving plate so as to be capable of conducting heat therethrough. A projector characterized by:

9. The cooling device according to claim 7; a heating element having a heat receiving plate, The heat exchanger of the cooling device is connected to the heat receiving plate so as to be capable of conducting heat therethrough. An electronic device characterized by:

Images