Flow path chip and method for producing flow path chip

Abstract

[Problem] To provide a flow path chip capable of performing processing such as measurement and analysis of a fluid by forming a flow path in a substrate and introducing the fluid into the flow path, the flow path chip capable of preventing branching of the fluid caused by the fluid remaining in the flow path even if a reciprocating motion of the fluid is continuously repeated. [Solution] A flow path chip in which a path through which a fluid flows is formed, the flow path chip comprising a communication path formed so as to extend in the vertical direction of the flow path chip, wherein the cross-sectional area of a lower end portion of the communication path is formed to be larger than the cross-sectional areas of other portions of the communication path.

Description

Flow path chip and method for manufacturing the same

[0001] The present invention relates to a flow path chip having a fluid flow path formed on a substrate and a method for manufacturing the flow path chip.

[0002] A flow path chip is used in which a flow path is formed on a substrate and a process such as measurement or analysis of a fluid is enabled by introducing the fluid into the flow path. In particular, a micro flow path chip capable of processing a fluid with a small amount of fluid is widely used in analysis in fields such as medical, environmental, and food. Before reaching reaction analysis, in the process of mixing, injecting, feeding, heating, and cooling the fluid in the flow path formed in the micro flow path chip, it is necessary to repeatedly reciprocate the fluid. Patent Document 1 discloses a micro flow path chip in which flow paths are formed on both surfaces of a plate-like base material, and the fluid flow path is formed by joining both surfaces of the base material to a covering base material.

[0003] Japanese Patent Application Laid-Open No. 2007-136379

[0004] In a structure in which the upper flow path and the lower flow path are connected as in the micro flow path chip described in Patent Document 1, fluid slightly adheres to the wall surface of the communication path that connects the upper flow path and the lower flow path after the fluid passes through the flow path. If the fluid adhering to this wall surface accumulates below the communication path due to its own weight, there is a possibility of blocking the lower side of the communication path. When fluid is further introduced in that state, bubbles are formed due to the fluid accumulated in the flow path, and there is a problem that accurate processing of the fluid cannot be performed.

[0005] The present invention provides a flow path chip that does not block the flow path due to the fluid remaining slightly on the inner wall surface of the flow path even when the reciprocating motion of the fluid is continuously repeated in the process of mixing, injecting, heating / cooling, and feeding the fluid in the flow path formed in the flow path chip. This prevents the branching of the fluid due to the fluid that accumulates due to its own weight.

[0006] The flow channel chip of the present invention is a flow channel chip in which a fluid path is formed, and has a connecting passage formed to extend in the vertical direction of the flow channel chip, wherein the cross-sectional area of ​​the lower end of the connecting passage is larger than the cross-sectional area of ​​the other parts of the connecting passage. The other parts of the connecting passage refer to the upper end of the connecting passage and the intermediate part located between the upper and lower ends of the connecting passage. In a flow channel chip configured as described above, when fluid is introduced intermittently, even if a small amount of previously introduced fluid remains at the lower end of the connecting passage, the flow channel is less likely to be sealed at the lower end of the connecting passage, which has a larger cross-sectional area.

[0007] In the above configuration, the width of the communication passage may be configured to increase linearly from top to bottom in a cross-sectional view. In a flow channel chip configured as described above, the communication passage is formed such that the cross-sectional area of ​​the communication passage gradually increases from top to bottom, thereby making the cross-sectional area of ​​the lower end of the communication passage larger than the cross-sectional area of ​​other parts of the communication passage.

[0008] In the above configuration, a plurality of communication passages may be formed, and in all of the plurality of communication passages, the cross-sectional area of ​​the lower end of the communication passage may be larger than the cross-sectional area of ​​the other parts of the communication passage. In a flow channel chip configured as described above, in a flow channel chip having a flow channel that reciprocates at multiple positions above and below the flow channel chip, the lower end of all communication passages is not sealed.

[0009] In the above configuration, the vertical direction may be configured to be the thickness direction of the flow channel chip. In a flow channel chip configured as described above, the communication passage extends in the thickness direction of the flow channel chip, and the cross-sectional area of ​​the communication passage is formed to be larger in the lower part in the thickness direction of the flow channel chip compared to other parts.

[0010] In the above configuration, the flow channel chip is composed of a base substrate, a first cover substrate, and a second cover substrate, with the base substrate positioned between the first cover substrate and the second cover substrate, and the communication passage is formed to penetrate the base substrate in the vertical direction, and the surface of the first cover substrate and the surface of the second cover substrate are in communication through the communication passage. In the flow channel chip configured as described above, the flow channel chip is formed by stacking three substrates, and the cross-sectional area of ​​the communication passage is formed to be larger below the communication passage that penetrates the base substrate positioned in the center, compared to other parts.

[0011] In the above configuration, the communication passage may be configured to be used as a microfluidic channel in which at least one of the vertical or horizontal widths is 1 mm or less. The channel tip configured as described above is used as a microfluidic tip having a channel of fine width.

[0012] The present invention can also be configured as a method for manufacturing a flow channel chip in which a fluid path is formed.

[0013] According to the present invention, even when the fluid undergoes continuous reciprocating motion during the processes of mixing, injecting, heating, and delivering fluids within the flow channels formed in the flow channel tip, it is possible to provide a flow channel tip that does not block the flow channels with a small amount of fluid remaining on the inner wall surface of the flow channels. This prevents fluid branching caused by fluid accumulating due to its own weight.

[0014] This is an exploded perspective view showing an example of a flow channel chip. This is a plan view of the flow channel chip shown in Figure 1. This is a cross-sectional view of the flow channel chip cut along line A-A in Figure 2. This is a schematic diagram showing the liquid flow when the cross-sectional area of ​​the connecting passage is uniform. This is a schematic diagram showing the liquid flow when using the flow channel chip of the present invention, in which the cross-sectional area of ​​the lower end of the connecting passage is made larger. This is an exploded perspective view showing another example of a flow channel chip. This is a cross-sectional view of the flow channel chip shown in Figure 6. This is a cross-sectional view showing another example of a flow channel chip. This is a perspective view showing another example of a flow channel chip. This is a perspective view showing another example of a typical connecting passage. This is a perspective view showing another example of a typical connecting passage. This is a perspective view showing another example of a flow channel chip. This is a perspective view showing another example of a flow channel chip.

[0015] Embodiments of the present invention will be described below with reference to the drawings shown as an example. Figure 1 is an exploded perspective view showing a flow channel chip 1 as an example of a flow channel chip. Figure 2 is a plan view of the flow channel chip 1. Figure 3 is a cross-sectional view of the flow channel chip 1 cut along the line A-A in Figure 2. In Figures 1 and 2, the fluid flow path formed inside the flow channel chip 1 is shown by a dashed line (the same applies hereafter). The flow channel chip 1 has a path formed in a substrate through which fluid flows. In this embodiment, a microfluidic chip that circulates liquid as a fluid in a microfluidic channel in which at least one of the width or height (depth) of the flow path is 1 mm or less will be described as an example. The flow channel chip 1 is composed of a base substrate 10 in which a liquid flow path is formed, a first cover substrate 20 joined to the upper surface of the base substrate 10, and a second cover substrate 30 joined to the lower surface of the base substrate 10. The base substrate 10, the first cover substrate 20, and the second cover substrate 30 are formed from, for example, resins such as thermoplastic resins, thermosetting resins, and photocurable resins, glass, or polydimethylsiloxane (PDMS). Examples of thermoplastic resins include polycarbonate, polyethylene, polypropylene, polyvinyl chloride, polyester, acrylic, cycloolefin polymer (COP), and cyclic olefin copolymer (COC). Examples of thermosetting resins include phenolic resin, polyurethane, and thermosetting polyimide. The base substrate 10, the first cover substrate 20, and the second cover substrate 30 can be manufactured by various molding methods, such as injection molding. In Figures 1 and 3, the base substrate 10, the first cover substrate 20, and the second cover substrate 30 are shown separated from each other, but the upper surface of the base substrate 10 and the lower surface of the first cover substrate 20, and the lower surface of the base substrate 10 and the upper surface of the second cover substrate 30 are joined together and used as the flow channel chip 1. The method of joining each substrate is not particularly limited, but for example, the substrates can be joined together by thermal fusion.

[0016] An upper channel 11 is formed on the upper surface of the base substrate 10 as a channel through which liquid flows. The upper channel 11 is a portion of the upper surface of the base substrate 10 that is recessed downwards. A first lower channel 12 and a second lower channel 13 are formed on the lower surface of the base substrate 10 as channels through which liquid flows. The first lower channel 12 and the second lower channel 13 are portions of the lower surface of the base substrate 10 that are recessed upwards. A first connecting passage 14 and a second connecting passage 15 are formed so as to penetrate the base substrate 10 in the vertical direction (thickness direction of the channel chip 1). The first connecting passage 14 connects the upper channel 11 and the first lower channel 12, and the second connecting passage 15 connects the upper channel 11 and the second lower channel 13. A liquid inlet 31 and a liquid outlet 32 ​​are formed on the second cover substrate 30 so as to penetrate the second cover substrate 30 in the vertical direction. In a plan view, the end of the first downward flow path 12 that does not communicate with the first connecting passage 14 is positioned to overlap with the inlet 31 of the second cover substrate 30. Also, the end of the second downward flow path 13 that does not communicate with the second connecting passage 15 is positioned to overlap with the location of the outlet 32. When the base substrate 10, the first cover substrate 20, and the second cover substrate 30 are joined together, a liquid flow path is formed in which liquid introduced from the inlet 31 passes through the first downward flow path 12, the first connecting passage 14, the upward flow path 11, the second connecting passage 15, and the second downward flow path 13 before being discharged from the outlet 32. Liquid is introduced into the flow path from the inlet 31 using a pump or the like (not shown).

[0017] The inlet 31 and outlet 32 ​​have a circular shape in plan view. The first connecting passage 14 and the second connecting passage 15 have a circular shape in plan view, but are formed so that their diameter gradually increases from the upper end to the lower end. In other words, the cross-sectional area of ​​the first connecting passage 14 and the second connecting passage 15 is formed so that it gradually increases from the upper end to the lower end. It can also be said that the first connecting passage 14 and the second connecting passage 15 have a conical shape with the top cut off. It can also be said that the width of the first connecting passage 14 and the second connecting passage 15 increases linearly from top to bottom in cross-sectional view. The first downward flow path 12 has an arc shape with the same diameter as the circular inlet 31 at one end and an arc shape with the same diameter as the circular first connecting passage 14 at the other end. The second downward flow path 13 has an arc shape with the same diameter as the circular outlet 32 ​​at one end and an arc shape with the same diameter as the circular second connecting passage 15 at the other end. Furthermore, when molding the base substrate 10 and the second cover substrate 30, it is possible to mold the shape of the upper channel 11, the first lower channel 12, the second lower channel 13, the first connecting passage 14, the second connecting passage 15, the inlet 31, and the outlet 32 ​​into the mold. Alternatively, it is possible to form the shape of the channels on the substrate after molding the basic shape of the base substrate 10 and the second cover substrate 30 using cutting, laser processing, or the like.

[0018] The effect of increasing the cross-sectional area of ​​the lower ends of the first communication passage 14 and the second communication passage 15 will be explained. Figure 4 is a schematic diagram showing the liquid flow when the cross-sectional area of ​​the communication passages is uniform, as a comparative example. In the flow path tip 1' according to the comparative example, liquid flows through the flow paths formed in the order of the first lower flow path 12', the first communication passage 14', the upper flow path 11', the second communication passage 15', and the second lower flow path 13'. Here, when the reciprocating motion of the liquid is continuously repeated during the process of mixing, injecting, raising / lowering temperature, and delivering the liquid, a small amount of liquid L remaining in the flow path adheres to the walls of the first communication passage 14' and the second communication passage 15', as shown in the upper part of Figure 4. Over time, the liquid L moves downward due to its own weight and accumulates at the lower ends of the first communication passage 14' and the second communication passage 15'. At this time, as shown in the lower part of Figure 4, there is a possibility that the liquid L will block the lower side of the first communication passage 14' and the second communication passage 15'. If the liquid continues to move back and forth in this state, a sealed state will form between the lower end of the first communication passage 14' and the lower end of the second communication passage 15', causing bubbles B to form. When bubbles B form, it becomes impossible to properly perform processes such as measuring or analyzing the liquid.

[0019] Figure 5 is a schematic diagram showing the liquid flow when using the flow channel tip 1 of the present invention, which has a large cross-sectional area at the lower end of the connecting passage. In the flow channel tip 1 shown in Figure 5, as the liquid repeatedly moves back and forth, the liquid L remaining in the flow channel adheres to the walls of the first connecting passage 14 and the second connecting passage 15, as shown in the upper part of Figure 5. Over time, the liquid L moves downward due to its own weight and accumulates at the lower ends of the first connecting passage 14 and the second connecting passage 15. Because the cross-sectional area at the lower ends of the first connecting passage 14 and the second connecting passage 15 is made large, as shown in the lower part of Figure 5, even if the liquid L accumulates at the lower ends of the first connecting passage 14 and the second connecting passage 15, it does not block the lower side of the first connecting passage 14 and the second connecting passage 15. When the liquid repeatedly moves back and forth in this state, a gap is formed between the remaining liquid L and the first connecting passage 14 and the second connecting passage 15, as shown in the lower part of Figure 5, so a sealed state is not achieved. Therefore, by using the flow channel tip 1 of the present invention, the generation of air bubbles is eliminated.

[0020] As described above, in the flow channel chip 1 of the present invention, the cross-sectional area of ​​the lower ends of the first communication passage 14 and the second communication passage 15 is made larger than that of the other parts of the first communication passage 14 and the second communication passage 15, so that even if the reciprocating motion of the liquid is repeated, a gap is formed between the liquid remaining at the lower ends of the communication passages and the communication passages. As a result, even if the reciprocating motion of the liquid is continuously repeated, it is possible to suppress the formation of bubbles caused by the liquid remaining in the flow channel. Furthermore, by forming an upper flow channel on the upper surface of the base substrate and a lower flow channel on the lower surface of the base substrate, forming a communication passage so as to penetrate the base substrate in the vertical direction, and joining the first cover substrate and the second cover substrate to the upper and lower surfaces of the base substrate, a flow channel chip having a sealed upper flow channel and a lower flow channel can be easily formed. Moreover, by forming an upper flow channel between the first lower flow channel and the second lower flow channel, and configuring the liquid to return to the lower flow channel via the upper flow channel, even if minute bubbles are generated, there is a high possibility that the bubbles will remain in the upper flow channel, thus suppressing the possibility that bubbles will affect processing such as measurement and analysis. Since a narrow channel width increases the likelihood of air bubbles affecting the processing, the present invention is particularly useful in microfluidic chips used as microfluidic channels where at least one of the vertical or horizontal width of the connecting passage is 1 mm or less.

[0021] Figure 6 is an exploded perspective view showing a flow channel chip 100 as another example of a flow channel chip. Figure 7 is a cross-sectional view of the flow channel chip 100. The flow channel chip 100 is composed of a base substrate 110 on which liquid flow channels are formed, a first cover substrate 120 joined to the upper surface of the base substrate 110, and a second cover substrate 130 joined to the lower surface of the base substrate 110. The first cover substrate 120 and the second cover substrate 130 are the same as the first cover substrate 20 and the second cover substrate 30, respectively, so their description is omitted. An upper flow channel 111 is formed on the upper surface of the base substrate 110 as a liquid flow channel. A first lower flow channel 112 and a second lower flow channel 113 are formed on the lower surface of the base substrate 110 as liquid flow channels. A first communication passage 114 and a second communication passage 115 are formed so as to penetrate the base substrate 110 in the vertical direction (thickness direction of the flow channel chip 100). The first connecting passage 114 connects the upper flow path 111 and the first lower flow path 112, and the second connecting passage 115 connects the upper flow path 111 and the second lower flow path 113. The first connecting passage 114 and the second connecting passage 115 have a rectangular (square) shape in plan view. The cross-sectional area of ​​the first connecting passage 114 and the second connecting passage 115 is formed to gradually increase from the upper end to the lower end. It can also be said that the first connecting passage 114 and the second connecting passage 115 have a square pyramidal shape with the upper part cut off. Except for the shape of the connecting passages, the base substrate 110 has the same structure as the base substrate 10. As described above, even if the cross-sectional shape of the connecting passages is rectangular, the effects of the present invention can be achieved by forming the connecting passages so that their cross-sectional area gradually increases from the upper end to the lower end.

[0022] Figure 8 is a cross-sectional view showing a flow channel chip 200 as another example of a flow channel chip. The flow channel chip 200 is composed of a base substrate 210 in which liquid flow channels are formed, a first cover substrate 220 joined to the upper surface of the base substrate 210, and a second cover substrate 230 joined to the lower surface of the base substrate 210. The first cover substrate 220 and the second cover substrate 230 are the same as the first cover substrate 20 and the second cover substrate 30, respectively, so their description is omitted. An upper flow channel 211 is formed on the upper surface of the base substrate 210 as a liquid flow channel. A first lower flow channel 212 and a second lower flow channel 213 are formed on the lower surface of the base substrate 210 as liquid flow channels. A first communication passage 214 and a second communication passage 215 are formed so as to penetrate the base substrate 210 in the vertical direction (thickness direction of the flow channel chip 200). The first connecting passage 214 connects the upper flow path 211 and the first lower flow path 212, and the second connecting passage 215 connects the upper flow path 211 and the second lower flow path 213. The first connecting passage 214 and the second connecting passage 215 have a rectangular shape in plan view. While the first connecting passage 114 and the second connecting passage 115 have a shape in which both sides are inclined in side view, the first connecting passage 214 and the second connecting passage 215 have one surface (the inner side) formed in the vertical direction (a direction perpendicular to the surface of the base substrate 210), and the other surface (the outer surface) is inclined. In this way, by inclining only one surface in side view, it is also possible to form the connecting passage so that the cross-sectional area gradually increases from the upper end to the lower end.

[0023] Figure 9 is a perspective view showing a flow channel chip 300 as another example of a flow channel chip. The flow channel chip 300 is composed of a base substrate 310. It differs from previous embodiments in that the thickness direction of the base substrate 310 is oriented horizontally rather than vertically. On one side of the base substrate 310, an upper flow channel 311, a first lower flow channel 312, a second lower flow channel 313, a first connecting passage 314, and a second connecting passage 315 are formed as liquid flow channels. In addition, a liquid inlet 331 and a liquid outlet 332 are formed so as to penetrate the thickness direction of the base substrate 310. Although not shown, by joining a cover substrate to only one side of the base substrate 310, a liquid flow channel is formed in which liquid introduced from the inlet 331 passes through the first lower flow channel 312, the first connecting passage 314, the upper flow channel 311, the second connecting passage 315, and the second lower flow channel 313 and is discharged from the outlet 332. The cross-sectional areas of the first passage 314 and the second passage 315 are not formed so that the cross-sectional area of ​​the flow path gradually increases throughout the entire passage, but rather gradually increases only near the lower ends of the first passage 314 and the second passage 315. As a result, the cross-sectional area at the lower ends of the first passage 314 and the second passage 315 is formed to be larger than that of other parts. As described above, the effects of the present invention can be achieved even when the thickness direction of the base substrate 310 is oriented horizontally rather than vertically. Furthermore, the effects of the present invention can be achieved not only when the overall cross-sectional area of ​​the passage is gradually increased, but also when the cross-sectional area is formed to be larger than that of other parts only near the lower ends of the passage. Moreover, the effects of the present invention can be achieved not only when flow paths are formed on both sides of the base substrate, but also when flow paths are formed on only one side of the base substrate.

[0024] Figure 10 is a perspective view showing a flow channel chip 400 as another example of a flow channel chip. The flow channel chip 400 is composed of a base substrate 410. The base substrate 410 is formed with its thickness oriented horizontally, similar to the base substrate 310. On one side of the base substrate 410, a first upper flow channel 411, a second upper flow channel 412, a lower flow channel 413, a first connecting passage 414, and a second connecting passage 415 are formed as liquid flow channels. In addition, a liquid inlet 431 and a liquid outlet 432 are formed so as to penetrate the thickness direction of the base substrate 410. Although not shown, by joining a cover substrate to only one side of the base substrate 410, a liquid flow channel is formed in which liquid introduced from the inlet 431 passes through the first upper flow channel 411, the first connecting passage 414, the lower flow channel 413, the second connecting passage 415, and the second upper flow channel 412 before being discharged from the outlet 432. The cross-sectional areas of the first communication passage 414 and the second communication passage 415 are formed such that the cross-sectional area gradually increases only near the lower ends of the first communication passage 414 and the second communication passage 415. As described above, the effects of the present invention can be achieved even in a configuration in which liquid introduced from the upper flow path passes through the lower flow path and is discharged from the upper flow path. Features

[0025] Figure 11 is a perspective view showing a communication passage 514 as another example of a communication passage. The communication passage 514 is linearly constructed on the base substrate. Although not shown, flow channels extend from the upper and lower ends of the communication passage 514. The cross-sectional area of ​​the communication passage 514 is formed such that the cross-sectional area gradually increases only near the lower end of the communication passage 514. As described above, in a configuration having a communication passage that extends in the vertical direction of the substrate, regardless of the presence or absence of an upper flow channel or a lower flow channel, the effects of the present invention can be achieved by making the cross-sectional area of ​​the lower end of the communication passage larger than that of other parts.

[0026] Figure 12 is a perspective view showing a communication passage 614 as another example of a communication passage. The communication passage 614 is configured in a curved shape on the base substrate. Although not shown, flow channels extend from the upper and lower ends of the communication passage 614. The cross-sectional area of ​​the communication passage 614 is formed so that the cross-sectional area gradually increases only near the lower end of the communication passage 614. As described above, the shape of the communication passage is not limited to a straight line, and the effects of the present invention can be achieved even with a curved communication passage by making the cross-sectional area at the lower end larger than that of other parts.

[0027] Figure 13 is a perspective view showing a flow channel chip 700 as another example of a flow channel chip. The flow channel chip 700 is composed of a base substrate 710. The base substrate 710 is formed with its thickness oriented horizontally, similar to the base substrate 310. On one side of the base substrate 710, a first upper flow channel 711, a second upper flow channel 712, a first connecting passage 714, and a second connecting passage 715 are formed as liquid flow channels. In addition, a liquid inlet 731 and a liquid outlet 732 are formed so as to penetrate the thickness direction of the base substrate 710. Although not shown, by joining a cover substrate to only one side of the base substrate 710, a liquid flow channel is formed in which liquid introduced from the inlet 731 passes through the first upper flow channel 711, the first connecting passage 714, the second connecting passage 715, and the second upper flow channel 712 and is discharged from the outlet 732. The cross-sectional area of ​​the first connecting passage 714 and the second connecting passage 715 is larger at the lower ends of the first and second connecting passages 714 and 715 than at other parts. Specifically, the connecting portion between the first and second connecting passages 714 and 715 is formed in a circular shape when viewed from the side, thereby increasing the cross-sectional area compared to other parts. As described above, the effects of the present invention can be achieved even in a configuration in which the connecting passages are connected without forming a lower flow path. Furthermore, it is not necessary to gradually increase the cross-sectional area at the lower ends of the connecting passages; it is sufficient that the cross-sectional area at the lower ends is large.

[0028] Figure 14 is a perspective view showing a flow channel chip 800 as another example of a flow channel chip. The flow channel chip 800 is composed of a base substrate 810. The base substrate 810 is formed with its thickness oriented horizontally, similar to the base substrate 310. On one side of the base substrate 810, a first downward flow channel 812, a second downward flow channel 813, a first connecting passage 814, and a second connecting passage 815 are formed as liquid flow channels. In addition, a liquid inlet 831 and a liquid outlet 832 are formed so as to penetrate the thickness direction of the base substrate 810. Although not shown, by joining a cover substrate to only one side of the base substrate 810, a liquid flow channel is formed in which liquid introduced from the inlet 831 passes through the first downward flow channel 812, the first connecting passage 814, the second connecting passage 815, and the second downward flow channel 813 and is discharged from the outlet 832. The cross-sectional areas of the first passage 814 and the second passage 815 are formed to be larger at the lower ends of the first passage 814 and the second passage 815 than at other parts. As described above, the effects of the present invention can be achieved even in a configuration in which the passages are connected without forming an upper flow path.

[0029] In the above embodiment, a microfluidic chip having a microfluidic channel in which at least one of the vertical or horizontal width of the channel is 1 mm or less was described as an example, but the channel width is not necessarily limited to 1 mm or less. The present invention is also applicable to microfluidic chips having a channel width greater than 1 mm.

[0030] In the above embodiments, the substrate material, molding method, and joining method are merely illustrative. As long as the flow path shape is as shown in the above embodiments, the effects of the present invention can be achieved regardless of the substrate material, etc.

[0031] In the above embodiment, examples were described in which the upper and lower flow channels were formed in a straight line in a plan view, but the shape of the flow channels is not limited to this. The upper and lower flow channels may form a complex network of flow channels in a plan view.

[0032] In the above embodiment, we described a connecting passage formed so as to extend vertically when the thickness direction of the substrate is oriented vertically, and a connecting passage formed so as to extend vertically when the thickness direction of the substrate is oriented horizontally. In either case, the connecting passage is formed so as to extend vertically when the flow channel substrate is used. In other words, in the present invention, the vertical direction is the direction assumed when the flow channel chip is used. Regardless of the orientation of the connecting passage with respect to the thickness direction or planar direction of the substrate, a flow channel that extends vertically when the flow channel chip is used is defined as a connecting passage.

[0033] In the above embodiment, a passage formed such that its cross-sectional area gradually increases from the upper end to the lower end, and a passage formed such that its cross-sectional area is large only near the lower end were described. In either case, the cross-sectional area of ​​at least the lower end of the passage is larger than the cross-sectional area of ​​other parts of the passage. Specifically, these other parts are the upper end of the passage and the intermediate part located between the upper and lower ends of the passage. The cross-sectional area of ​​the lower end of the passage should be made larger than the cross-sectional area of ​​the upper end and the cross-sectional area of ​​the intermediate part of the passage. Note that the cross-sectional area is the cross-sectional area when the flow path is cut perpendicular to the direction of liquid flow. Furthermore, in a configuration having a passage that extends in the vertical direction of the substrate when no flow path is formed, the effects of the present invention can be achieved by making the cross-sectional area of ​​the lower end of the passage larger than that of other parts.

[0034] In the above embodiment, for the sake of simplicity, the explanation used a flow path that makes at most one return trip between the upper flow path and the lower flow path. However, the present invention is also applicable to complex flow paths that make multiple return trips between the upper flow path and the lower flow path. In that case, three or more connecting passages are formed, and the effects of the present invention can be achieved by making the cross-sectional area of ​​the lower end of each connecting passage larger than the cross-sectional area of ​​other parts of the connecting passage.

[0035] It goes without saying that the present invention is not limited to the embodiments described above. As will be obvious to those skilled in the art, the following are disclosed as embodiments of the present invention: - Applying the mutually interchangeable members and configurations disclosed in the embodiments by appropriately changing their combinations; - Applying members and configurations that are not disclosed in the embodiments but are known and mutually interchangeable with the members and configurations disclosed in the embodiments, by appropriately substituting them and changing their combinations; - Applying members and configurations that are not disclosed in the embodiments but that a person skilled in the art could conceive of as substitutes for the members and configurations disclosed in the embodiments based on known technology, by appropriately substituting them and changing their combinations.

[0036] 1, 1', 100, 200, 300, 400, 700, 800...flow channel chip, 10, 110, 210, 310, 410, 710, 810...base substrate, 11, 11', 111, 211, 311...upper flow channel, 12, 12', 112, 212, 312, 812...first downward flow channel, 13, 13', 113, 213, 313, 813...second downward flow channel, 14, 14', 114, 214, 314, 414, 814...first Connecting passage, 15, 15', 115, 215, 315, 415, 815... Second connecting passage, 20, 120, 220... First cover substrate, 30, 130, 230... Second cover substrate, 31, 331, 431, 731, 831... Inlet, 32, 332, 432, 732, 832... Outlet, 411, 711... First upper flow path, 412, 712... Second upper flow path, 413... Lower flow path, 514, 614... Connecting passage, B... Bubble, L... Liquid.

Claims

1. A flow channel chip having a fluid path formed therein, wherein the flow channel chip has a connecting passage formed to extend in the vertical direction, and the cross-sectional area of ​​the lower end of the connecting passage is larger than the cross-sectional area of ​​other parts of the connecting passage.

2. The flow path chip according to claim 1, characterized in that the cross-sectional area of ​​the lower end of the communication passage is larger than the cross-sectional area of ​​the upper end of the communication passage.

3. The flow path chip according to claim 1, characterized in that the cross-sectional area of ​​the lower end of the communication passage is larger than the cross-sectional area of ​​the intermediate portion located midway between the upper end and the lower end of the communication passage.

4. The flow channel tip according to claim 1, characterized in that the width of the connecting passage increases linearly from top to bottom in a cross-sectional view.

5. The flow channel tip according to claim 1, characterized in that a plurality of communication passages are formed, and in all of the plurality of communication passages, the cross-sectional area of ​​the lower end of the communication passage is larger than the cross-sectional area of ​​the other parts of the communication passage.

6. The flow channel tip according to claim 1, characterized in that the vertical direction is the thickness direction of the flow channel tip.

7. The flow channel chip according to claim 1, comprising a base substrate, a first cover substrate, and a second cover substrate, wherein the base substrate is positioned between the first cover substrate and the second cover substrate, the communication passage is formed to penetrate the base substrate in the vertical direction, and the surface of the first cover substrate and the surface of the second cover substrate are in communication through the communication passage.

8. The channel tip according to claim 1, characterized in that it is used as a microchannel in which at least one of the vertical or horizontal width of the communication passage is 1 mm or less.

9. A method for manufacturing a flow channel chip in which a fluid path is formed, comprising the step of forming a connecting passage so as to extend in the vertical direction of the flow channel chip, wherein the cross-sectional area of ​​the lower end of the connecting passage is larger than the cross-sectional area of ​​other parts of the connecting passage.

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