Flow path substrate

Abstract

A first flow path (132) and a second flow path (133) of this flow path substrate connect a first storage unit (131), which is capable of storing a fluid entering through an inflow port (135), and a second storage unit (134). The first flow path (132) is connected to the first storage unit (131) at a position further from the inflow port (135) than the second flow path (133), and is thinner than the second flow path (133).

Description

Flow path substrate

[0001] The present disclosure relates to a flow path substrate.

[0002] 2. Description of the Related Art There are known flow path substrates that control fluids such as liquids through flow paths. For example, Patent Document 1 discloses a flow path substrate that collects a minute amount of liquid through a flow path.

[0003] Japanese Patent Application Publication No. 2014-163104

[0004] A flow path substrate according to an embodiment of the present disclosure includes a first reservoir capable of storing a fluid entering through an inlet, a first flow path and a second flow path connected to the first reservoir, respectively, and a second reservoir connected to the first flow path and the second flow path. The first flow path is connected to the first reservoir at a position farther away from the inlet than the second flow path and is narrower than the second flow path.

[0005] 10 is a perspective view of a flow path substrate according to a first embodiment. FIG. 11 is a cross-sectional view of the flow path substrate according to the first embodiment, taken along a plane including line A-A in FIG. 1. FIG. 2 is a partially enlarged view of the flow path substrate according to the first embodiment, taken along a dotted line in FIG. 2. FIG. 2 is a diagram showing an example of a flow of fluid stored in a detection unit of the flow path substrate according to the first embodiment. FIG. 3 is a partially enlarged view of the flow path substrate according to the second embodiment, taken along a plane including line B-B in FIG. 9. FIG. 11 is a partially enlarged view of the flow path substrate according to the third embodiment, taken along a plane including line B-B in FIG. 9. FIG. 12 is a partially enlarged view of the flow path substrate according to the sixth embodiment, taken along a plane including line B-B in FIG. 10. FIG. 13 is a partially enlarged view of the flow path substrate according to the sixth embodiment, taken along a dotted line in FIG. 14. FIG. 14 is a partially enlarged view of the flow path substrate according to the seventh embodiment, taken along a plane including line B-B in FIG. 15. 19 is a cross-sectional view of a flow path substrate according to a ninth embodiment, taken along a plane including line CC in FIG. 16 . FIG. 20 is a partially enlarged view of a flow path substrate according to the ninth embodiment, taken along a plane including line CC in FIG. 16 . FIG. 21 is a partially enlarged view of a flow path substrate according to the ninth embodiment, taken along a plane including line D-D in FIG. 19 . FIG. 22 is a partially enlarged view of a flow path substrate according to an eleventh embodiment, taken along a plane including line D-D in FIG. 19 . FIG. 23 is a partially enlarged view of a flow path substrate according to an eleventh embodiment, taken along a plane including line D-D in FIG. 20 . FIG. 24 is a partially enlarged view of a flow path substrate according to an eleventh embodiment, taken along a plane including line D-D in FIG. 21 .

[0006] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In this specification, unless otherwise specified, "X to Y" representing a numerical range means "greater than or equal to X and less than or equal to Y." In this specification, unless otherwise specified, "X / Y" means "the value obtained by dividing X by Y." In this specification, "fluid" refers not only to simple liquids but also to liquids containing solids and gases. For example, "fluid" includes a specimen. For convenience of explanation, in FIGS. 10, 11, 12, 13, and 14, the positive direction of the Y axis is the upward direction, the negative direction of the Y axis is the downward direction, the positive direction of the X axis is the rightward direction, and the negative direction of the X axis is the leftward direction.

[0007] First Embodiment A flow path substrate 1 according to a first embodiment will be described below with appropriate reference to the drawings. The flow path substrate 1 is a substrate used for detecting a target substance contained in a specimen 60. The flow path substrate 1 may also be used for quantifying the target substance contained in the specimen 60. A flow path 10 is formed inside the flow path substrate 1. When the specimen 60 is introduced into the flow path substrate 1, the specimen 60 and a reagent are mixed inside the flow path substrate 1. The specimen 60 mixed with the reagent is temporarily stored in a detection unit 13. For example, "storage" refers to the specimen 60 remaining in a certain region relative to the flow in the flow path 10, but is not limited to this.

[0008] For example, the specimen 60 may include a substance derived from a living organism. For example, the specimen 60 may include a substance derived from a mammal, such as a human, a dog, a cat, or a cow. For example, the specimen 60 may include a substance excreted from a living organism or a substance extracted from a living organism. For example, the specimen 60 may include urine, blood, sweat, saliva, or nasal secretions. For example, the target substance may be a virus, a bacterium, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), or a protein.

[0009] For example, the reagent may include a substrate that reacts with the target substance or a nucleic acid or enzyme contained in the target substance. For example, the reagent may include a substrate that reacts with the target substance or a nucleic acid or enzyme contained in the target substance and emits fluorescence. For example, the reagent may include probe DNA, probe RNA, or the like designed to detect the target substance or a nucleic acid contained in the target substance. For example, the reagent may include primer DNA, an enzyme, or the like for amplifying the target substance or a nucleic acid contained in the target substance.

[0010] The configuration of the flow path substrate 1 will be described with reference to Figures 1, 2, 3, and 4. As shown in Figure 1, the flow path substrate 1 has a rectangular parallelepiped shape. For example, the flow path substrate 1 may have a curved surface, a spherical surface, a concave surface, or a convex surface in part. For example, the flow path substrate 1 may be located in part or in whole inside a housing made of resin, metal, or the like. For example, the flow path substrate 1 may be made of a single member. For example, the flow path substrate 1 may be made by combining two or more members.

[0011] As shown in FIG. 2 , the flow path substrate 1 has a flow path 10 therein. The flow path substrate 1 has an inlet hole 11, a reagent dissolving section 12, a detection section 13, and an outlet hole 14. The inlet hole 11 can introduce a specimen 60 into the flow path substrate 1. The reagent dissolving section 12 is configured to dissolve a reagent in the specimen 60. The detection section 13 can store the specimen 60 mixed with the reagent. The flow path substrate 1 has a plurality of detection sections 13. The outlet hole 14 can discharge, to the outside of the flow path substrate 1, the specimen 60 introduced from the inlet hole 11 that is introduced after the detection section 13 is filled. The flow path substrate 1 has a plurality of outlet holes 14.

[0012] When detecting a target substance contained in a specimen 60 using the flow channel substrate 1, the specimen 60 is first introduced through the inlet 11. The specimen 60 introduced through the inlet 11 is mixed with a reagent in the reagent dissolving section 12. The specimen 60 mixed with the reagent in the reagent dissolving section 12 is stored in the detection section 13. After the specimen 60 is stored in the detection section 13, the target substance is detected by observing the specimen 60 stored in the detection section 13. For example, the reagent may contain a substrate that reacts with the target substance and emits fluorescence. In this case, the specimen 60 may be observed by irradiating the detection section 13 with excitation light. While the detection section 13 is irradiated with excitation light, the target substance may be detected based on the fluorescence emitted from the substrate in the specimen 60.

[0013] The flow path substrate 1 further has a branching section 15 located between the introduction hole 11 and the reagent dissolving section 12. By having the branching section 15, the flow path substrate 1 can simultaneously detect a target substance under a plurality of conditions. The flow path substrate 1 further has a filter section 16 located between the introduction hole 11 and the branching section 15. By having the filter section 16, the flow path substrate 1 can separate solids or air bubbles contained in the specimen 60. As a result, the risk that solids or air bubbles contained in the specimen 60 will interfere with the detection of the target substance in the detection section 13 can be reduced.

[0014] The flow path substrate 1 has a first surface 17 and a second surface 18 facing the first surface 17. The second surface 18 is the back surface of the flow path substrate 1 relative to the first surface 17. The top surface of the flow path 10 is the surface of the flow path 10 that is located on the first surface 17 side. The bottom surface of the flow path 10 is the surface of the flow path 10 that is located on the second surface 18 side. The side surface of the flow path 10 is the surface of the flow path 10 that is not facing the first surface 17 or the second surface 18.

[0015] For example, the material of the flow path substrate 1 may be resin, glass, ceramic, metal, or the like. For example, the material of the flow path substrate 1 may be cyclic olefin polymer, cyclic olefin copolymer, acrylic resin, unstretched polypropylene, or the like. The flow path substrate 1 may be made of a plurality of materials. For example, the flow path substrate 1 may be formed by injection molding, resin cutting, photolithography, or the like. The cross section perpendicular to the first surface 17 of the flow path 10 has a rectangular shape. For example, the cross section perpendicular to the first surface 17 of the flow path 10 may have a shape such as an approximately circular shape, an elliptical shape, a trapezoidal shape, or a triangular shape.

[0016] (Introduction hole 11) The introduction hole 11 can introduce the analyte 60 into the inside of the flow path substrate 1. The introduction hole 11 can introduce the analyte 60 into the flow path 10. The introduction hole 11 connects the outside of the flow path substrate 1 with the flow path 10. The introduction hole 11 is a first end of the flow path 10. The introduction hole 11 opens to one of the surfaces of the flow path substrate 1. The introduction hole 11 opens to a first surface 17 of the flow path substrate 1.

[0017] The shape of the introduction hole 11 may be selected arbitrarily. For example, the space located inside the introduction hole 11 has a truncated cone shape. For example, the space located inside the introduction hole 11 may have a triangular pyramid shape, a quadrangular prism shape, a cylindrical shape, a rectangular prism shape, or the like. The introduction hole 11 has a shape in which the cross-sectional area of ​​the introduction hole 11 decreases from the first surface 17 toward the second surface 18 opposite the first surface 17. The opening of the introduction hole 11 is substantially circular. For example, the opening of the introduction hole 11 may be elliptical, rectangular, hexagonal, octagonal, or the like.

[0018] (Reagent dissolving unit 12) The reagent dissolving unit 12 can dissolve the reagent in the specimen 60. The reagent dissolving unit 12 can dissolve the reagent in the specimen 60 flowing through the flow path. In the reagent dissolving unit 12, the reagent is located on the bottom surface of the flow path. In the reagent dissolving unit 12, the reagent may be located on the side surface of the flow path. The shape of the reagent dissolving unit 12 can be selected arbitrarily. For example, the reagent dissolving unit 12 has a linear or curved shape. The curved shape of the reagent dissolving unit 12 may be an arc or L-shape. For example, the reagent dissolving unit 12 of this embodiment has a shape in which arc shapes and linear shapes are alternately repeated. In order for the reagent dissolving unit 12 to dissolve the reagent in the specimen 60, the reagent dissolving unit 12 does not have to have a curved shape. In this embodiment, the width of the flow path of the reagent dissolving unit 12 is constant. For example, the width of the flow path of the reagent dissolving unit 12 may vary. For example, the width of the flow channel of the reagent dissolving section 12 may be widened only in a portion thereof.

[0019] (Detection unit 13) The detection unit 13 can store the specimen 60. "Storage" refers to temporarily storing a fluid. "Storage" includes not only storing the same fluid, but also storing a fluid while a portion of the fluid is replaced. The detection unit 13 can store the specimen 60 mixed with a reagent. For example, when detecting a target substance using light using the flow path substrate 1, the surface on the first surface 17 side and the surface on the second surface 18 side of the detection unit 13 may be light-transmitting.

[0020] As shown in FIG. 4 , the detection unit 13 has a first storage section 131, a first flow path 132, a second flow path 133, and a second storage section 134. The first storage section 131 can store the sample 60 that has entered through an inlet 135. When viewed from the first surface 17, the first storage section 131 has a region that narrows toward the downstream side. The first storage section 131 has a region that narrows toward the downstream side. The first storage section 131 has a region that narrows toward the first connection section, which is the connection section with the first flow path 132. The first storage section 131 is thicker than the second flow path 133. Here, in this specification, "thickness" refers to the cross-sectional area perpendicular to the extension direction of the flow path. The "extension direction of the flow path" refers to the direction in which the spaces formed by the flow paths are continuously located. For example, the "extension direction of the flow path" refers to the direction in which a fluid flows when the fluid is flowed through the flow path, but is not limited thereto. For example, the width of the first reservoir may be 100 μm to 500 μm. For example, the depth of the first reservoir may be 25 μm to 200 μm. For example, the ratio of the thickness of the first reservoir 131 to the thickness of the second flow path 133, in other words, the thickness of the first reservoir 131 / the thickness of the second flow path 133, may be 2.0 or greater.

[0021] The direction in which the fluid flows from the inlet 135 toward the first connection portion of the first storage portion 131 and the first flow path 132 is defined as a first direction. The first storage portion 131 has a region in which the cross-sectional area in a cross section perpendicular to the first direction decreases toward the first direction. For example, the first storage portion 131 has a region in which the cross-sectional area in a cross section perpendicular to the first direction is constant toward the first direction. The first storage portion 131 has a region that narrows toward the first direction. The length of the first storage portion 131 in the first direction is greater than the length of the first storage portion 131 in the direction perpendicular to the first direction.

[0022] A first line is a line connecting inlet 135 and a first connection portion between first reservoir 131 and first flow path 132. For example, first reservoir 131 has a region in which the cross-sectional area in a cross section perpendicular to the first line becomes smaller as it approaches first flow path 132. For example, first reservoir 131 has a region in which the cross-sectional area in a cross section perpendicular to the first line gradually becomes smaller. First reservoir 131 has a region in which the cross-sectional area in a cross section perpendicular to the first line is constant.

[0023] The first flow path 132 is a flow path through which the fluid stored in the first storage portion 131 can pass. The first flow path 132 is a flow path through which the fluid stored in the first storage portion 131 can flow in. For example, the first flow path 132 is a flow path through which the gas stored in the first storage portion 131 can pass. The first flow path 132 is connected to the first storage portion 131. The first flow path 132 is connected to the narrowest portion of the first storage portion 131. A first end of the first flow path 132 is connected to the first storage portion 131.

[0024] For example, the thickness of the first flow path 132 is narrower than that of the first reservoir 131. For example, the width of the first flow path 132 may be 5.0 μm to 50 μm. For example, the depth of the first flow path 132 may be 25 μm to 200 μm. For example, the ratio of the thickness of the first flow path 132 to that of the first reservoir 131, in other words, the ratio (thickness of the first flow path 132 / thickness of the first reservoir 131) may be 0.10 or less. The thickness of the first flow path 132 is narrower than that of the reagent dissolving section 12. For example, the first flow path 132 is narrower than that of the second flow path 133. For example, the ratio of the thickness of the first flow path 132 to that of the second flow path 133, in other words, the ratio (thickness of the first flow path 132 / thickness of the second flow path 133) may be 0.50 or less. The length of the first flow path 132 is longer than that of the second flow path 133. For example, the length of the first flow path may be 500 μm to 2500 μm. For example, the ratio of the length of the first flow path 132 to the length of the second flow path 133, in other words, the length of the first flow path 132 / the length of the second flow path, may be 2.0 or more.

[0025] First flow path 132 has a region extending in a direction away from first storage portion 131 and a region extending in a direction approaching first storage portion 131. First flow path 132 has a region extending in the longitudinal direction of first storage portion 131. The region of first flow path 132 extending in the longitudinal direction of first storage portion 131 is connected to first storage portion 131.

[0026] The second flow path 133 is a flow path through which the fluid stored in the first storage portion 131 can pass. The second flow path 133 is connected to the first storage portion 131. A first end of the second flow path 133 is connected to the first storage portion 131. The second flow path 133 is connected to the first storage portion 131 at a position closer to the inlet 135 than the first flow path 132. The second flow path 133 extends from the first storage portion 131 in a direction different from that of the first flow path 132.

[0027] The second flow path 133 is narrower than the first reservoir 131. The second flow path 133 is wider than the first flow path 132. For example, the width of the second flow path 133 may be 25 μm to 150 μm. For example, the depth of the second flow path 133 may be 25 μm to 200 μm. The length of the second flow path 133 is smaller than the length of the first flow path 132. The length of the second flow path 133 may be longer than the length of the first flow path 132. For example, the length of the second flow path 133 may be 200 μm to 1000 μm. The volume of the second flow path 133 is larger than the volume of the first flow path 132. The second flow path 133 is connected to the second reservoir 134 at a position facing the first flow path 132.

[0028] The second reservoir 134 can store the fluid that flows in from the first flow path 132 and the second flow path 133. The second reservoir 134 can store the fluid that flows out from the first reservoir 131. The second reservoir 134 can store the fluid that flows in from the first flow path 132 after flowing out from the first reservoir 131. The second reservoir 134 can store the fluid that flows in from the second flow path 133 after flowing out from the first reservoir 131.

[0029] The second reservoir 134 is connected to the first flow path 132 and the second flow path 133. The second reservoir 134 is connected to a second end of the first flow path 132. The second reservoir 134 is connected to an end of the first flow path 132 opposite to the end connected to the first reservoir 131. The second reservoir 134 is connected to a second end of the second flow path 133. The second reservoir 134 is connected to an end of the second flow path 133 opposite to the end connected to the first reservoir 131.

[0030] The second reservoir 134 is connected to the first flow path 132 and the second flow path 133 so that the flow of the fluid flowing in from the first flow path 132 and the flow of the fluid flowing in from the second flow path 133 are opposite each other. The second reservoir 134 is connected to the first flow path 132 and the second flow path 133 at positions facing each other.

[0031] The volume of second reservoir 134 is smaller than the volume of first reservoir 131. The volume of second reservoir 134 is larger than the volume of first flow path 132. The volume of second reservoir 134 is larger than the volume of second flow path 133.

[0032] The detection unit 13 further includes a third flow path 136 connected to the inlet 135. The third flow path 136 allows the specimen 60 to flow into the first reservoir 131. The third flow path 136 is connected to the first reservoir 131. The third flow path 136 is narrower than the first reservoir 131. The portion of the third flow path 136 connected to the inlet is narrower than the first reservoir 131. The portion of the third flow path 136 connected to the inlet is narrower than the widest portion of the first reservoir 131. The third flow path 136 may be wider than the first reservoir 131. The third flow path 136 is wider than the first flow path 132. For example, the width of the third flow path 136 may be 25 μm to 300 μm. For example, the depth of the third flow path 136 may be 25 μm to 200 μm. For example, the ratio of the thickness of the third flow path 136 to the thickness of the first flow path 132, in other words, the ratio (thickness of the third flow path 136) / (thickness of the first flow path 132) may be 5.0 or more. The third flow path 136 is thicker than the second flow path 133. For example, the ratio of the thickness of the third flow path 136 to the thickness of the second flow path 133, in other words, the ratio (thickness of the third flow path 136) / (thickness of the second flow path 133) may be 1.5 or more.

[0033] Third flow path 136 is connected to first reservoir 131 so that the flow of fluid flowing from third flow path 136 into first reservoir 131 and the flow of fluid flowing from first reservoir 131 into first flow path 132 are in the same direction. Third flow path 136 is connected to first reservoir 131 so as to extend along the longitudinal direction of first reservoir 131. Third flow path 136 has a region extending in the longitudinal direction of first reservoir 131. The region of the third flow path extending in the longitudinal direction of first reservoir 131 is connected to first reservoir 131.

[0034] The detection unit 13 further has a fourth flow path 137 connected to the second storage portion 134. The fourth flow path 137 is a flow path through which the fluid stored in the second storage portion 134 can pass. A first end of the fourth flow path 137 is connected to the second storage portion 134. The fourth flow path 137 may be connected to the outside of the flow path substrate 1. The fourth flow path 137 is connected to the outlet hole 14. The fourth flow path 137 is connected to the outside of the flow path substrate 1 via the outlet hole 14.

[0035] The fourth flow path 137 is wider than the first flow path 132. For example, the width of the fourth flow path 137 may be 10 μm to 200 μm. For example, the depth of the fourth flow path 137 may be 25 μm to 200 μm. For example, the ratio of the thickness of the fourth flow path 137 to the thickness of the first flow path 132, in other words, the ratio (thickness of the fourth flow path 137) / (thickness of the first flow path 132) may be 1.5 or more. The fourth flow path 137 is thinner than the second flow path 133. For example, the ratio of the thickness of the fourth flow path 137 to the thickness of the second flow path 133, in other words, the ratio (thickness of the fourth flow path 137) / (thickness of the second flow path 133) may be 0.8 or less. The second direction is the direction in which the fluid flows from the third connection portion, which is the connection portion between the second storage portion 134 and the second flow path 133, toward the fourth connection portion, which is the connection portion between the second storage portion 134 and the fourth flow path 137. The second storage portion 134 has a region in which the cross-sectional area in a cross section perpendicular to the second direction decreases toward the second direction.

[0036] (Outlet hole 14) The outlet hole 14 can lead the analyte 60 from inside the flow path substrate 1 to the outside of the flow path substrate 1. The outlet hole 14 can lead the analyte 60 from the flow path 10 to the outside of the flow path substrate 1. The outlet hole 14 is a second end of the flow path of the flow path substrate 1. The outlet hole 14 opens to one of the surfaces of the flow path substrate 1. The outlet hole 14 opens to a first surface 17 of the flow path substrate 1.

[0037] The shape of the lead-out hole 14 may be selected arbitrarily. For example, the space located inside the lead-out hole 14 has a truncated cone shape. For example, the space located inside the lead-out hole 14 may have a triangular pyramid shape, a square pyramid shape, a cylindrical shape, a square prism shape, or the like. The lead-out hole 14 has a shape in which the cross-sectional area of ​​the lead-out hole 14 decreases from the first surface 17 toward the second surface 18 opposite the first surface 17. For example, the opening of the lead-out hole 14 is substantially circular. For example, the opening of the lead-out hole 14 may have a rectangular shape, a hexagonal shape, an octagonal shape, or the like.

[0038] (Branching section 15) The branching section 15 branches the flow path of the flow path substrate 1 into multiple paths. For example, the branching section 15 branches the flow path of the flow path substrate 1 into four paths. The number of paths to be branched is not limited to this and can be set to any number. The branching section 15 branches the flow path of the flow path substrate 1 to the left and right. The branching section 15 is located between the introduction hole 11 and the reagent dissolving section 12. For example, the branching section 15 may be located between the reagent dissolving section 12 and the detection section 13.

[0039] (Filter section 16) The filter section 16 can separate solids or air bubbles contained in the sample 60. The filter section 16 is located between the introduction hole 11 and the branching section 15. For example, the filter section 16 may be located between the branching section 15 and the reagent dissolving section 12. For example, the filter section 16 has the thickest region of the flow path 10.

[0040] (Storage of analyte 60 in detection unit 13) The flow of analyte 60 stored in the first storage unit 131 of the detection unit 13 will be described below with reference to FIG. 4. The analyte 60 introduced through the inlet 11 of the flow path substrate 1 is mixed with the reagent located in the reagent dissolving unit 12, and the reagent dissolves in the analyte 60. Here, of the analyte 60 flowing through the reagent dissolving unit 12, the leading portion 61 of the analyte 60 introduced through the inlet 11 is likely to have a high concentration of dissolved reagent. Referring to FIGS. 4A and 4B, the leading portion 61 passes through the inlet 135 and then moves in a direction to fill the first storage unit 131. After the analyte 60 fills the first storage unit 131, the analyte 60 that flows into the first storage unit 131 from the third flow path 136 flows out of the first flow path 132 or the second flow path 133.

[0041] When a flow path substrate having a first flow path that is wider than the second flow path is used, after the first reservoir is filled with the sample, the sample that flows into the first reservoir from the third flow path flows out of the first flow path, which is wider than the second flow path. Here, because the first flow path is connected to the first reservoir at a position farther from the inlet than the second flow path, the leading edge of the sample flows out of the first flow path. Furthermore, when a flow path substrate is used in which the first flow path is connected to the first reservoir at a position closer to the inlet than the second flow path, the leading edge of the sample flows out of the second flow path.

[0042] On the other hand, in the flow path substrate 1, the first flow path 132 is connected to the first reservoir 131 at a position farther from the inlet 135 than the second flow path 133, and is narrower than the second flow path 133. Referring to FIG. 4C , because the second flow path 133 is wider than the first flow path 132, most of the analyte 60 that flows from the third flow path 136 into the first reservoir 131 passes through the upstream side of the first reservoir 131 and flows out of the second flow path 133. This reduces the amount of analyte 60 that flows out of the first flow path 132. As a result, the first reservoir 131 can store a larger amount of the leading end portion 61.

[0043] When a flow path substrate without a second reservoir is used, the gas in the first flow path flows out from the second end of the first flow path. Then, the sample stored in the first reservoir flows out from the first flow path. As a result, the leading edge of the sample flows out from the first flow path.

[0044] On the other hand, the flow path substrate 1 has a second reservoir 134 connected to the first flow path 132 and the second flow path 133. Referring to FIG. 4C , the analyte 60 that flows out from the first reservoir 131 to the second flow path 133 flows from the second flow path 133 into the second reservoir 134. When the analyte 60 is stored in the second reservoir 134, the connection between the first flow path 132 and the second reservoir 134 is blocked by the analyte 60. Referring to FIG. 4E , when the connection between the first flow path 132 and the second reservoir 134 is blocked by the analyte 60, the fluid located in the first flow path 132 cannot flow out to the second reservoir 134 and is retained within the first flow path 132. Therefore, the outflow of the analyte 60 from the first reservoir 131 to the first flow path 132 is reduced. As a result, the first reservoir 131 can store a larger amount of the leading portion 61.

[0045] In the flow path substrate 1 of this embodiment, the first flow path 132 is connected to the first reservoir 131 at a position farther from the inlet 135 than the second flow path 133, and is narrower than the second flow path 133. This reduces the amount of specimen 60 flowing out of the first flow path 132. As a result, the first reservoir 131 can store a larger amount of the leading end portion 61.

[0046] Second Embodiment A flow path substrate 2 according to a second embodiment will now be described. The flow path substrate 2 is different from the flow path substrate 1 in the configuration of the detection unit 23. As shown in Fig. 5 , the detection unit 23 of the flow path substrate 2 is such that the second flow path 233 is connected to a more downstream side of the first storage portion 231 compared to the flow path substrate 1. The second flow path 233 is connected to the center of the first storage portion 231 in the longitudinal direction of the first storage portion 231.

[0047] After the first reservoir 231 is filled with the specimen 60, the specimen 60 flows from the third flow path 236 into the first reservoir 231, travels to the center of the first reservoir 231, and then flows out of the second flow path 233. The specimen 60 located downstream of the portion of the first reservoir 231 connected to the second flow path 233 contains a larger amount of the leading portion 61. Therefore, in the flow path substrate 2 of this embodiment as well, the first reservoir 231 can store a larger amount of the leading portion 61.

[0048] Third Embodiment A flow path substrate 3 according to a third embodiment will now be described. The flow path substrate 3 is different from the flow path substrate 1 in the configuration of the detection unit 33. As shown in FIG. 6 , the detection unit 33 of the flow path substrate 3 is different from that of the flow path substrate 1 in that the first flow path 332 is connected to a more upstream side of the first storage portion 331. The first flow path 332 is connected to a side of the first storage portion 331. The first flow path 332 is connected to the first storage portion 331 in the same direction as the second flow path 333 is located. The first flow path 332 is connected to the first storage portion 331 in the same direction as the second flow path 333 is connected to.

[0049] The first flow path 332 extends from the first storage portion 331 in a direction intersecting the longitudinal direction of the first storage portion 331. The first flow path 332 extends from the first storage portion 331 in a direction perpendicular to the longitudinal direction of the first storage portion 331. In the flow path substrate 3 of this embodiment as well, the first storage portion 331 can store a larger amount of the leading portion 61.

[0050] <Fourth embodiment> A flow path substrate 4 according to the fourth embodiment will be described below. The flow path substrate 4 differs from the flow path substrate 1 in the configuration of the detection unit 43. As shown in Fig. 7, the detection unit 43 of the flow path substrate 4 does not have a configuration corresponding to the second reservoir 434 in the flow path substrate 1. In the detection unit 43 of the flow path substrate 4, the first flow path 432 and the second flow path 433 are directly connected. The first flow path 432 is connected to the second flow path 433 such that the flow of the analyte 60 in the first flow path 432 and the flow of the analyte 60 in the second flow path 433 are opposite each other.

[0051] The fourth flow path 437 extends from the connection portion of the first flow path 432 and the second flow path 433. The fourth flow path 437 is connected to the connection portion of the first flow path 432 and the second flow path 433 so that the flow of the analyte 60 in the first flow path 432 and the flow of the analyte 60 in the second flow path 433 intersect.

[0052] In the flow path substrate 4 of this embodiment, the analyte 60 that flows out from the first reservoir 431 to the second flow path 433 flows into the fourth flow path 437 from the connection portion between the first flow path 432 and the second flow path 433. When the connection portion between the first flow path 432 and the second flow path 433 is filled with the analyte 60, the fluid located in the first flow path 432 cannot flow out to the second flow path 433 and the fourth flow path 437. When the fluid located in the first flow path 432 cannot flow out to the second flow path 433 and the fourth flow path 437, the fluid located in the first flow path 432 is retained within the first flow path 432. This reduces the outflow of the analyte 60 from the first reservoir 431 to the first flow path 432. As a result, even in the flow path substrate 4, the first reservoir 431 can store a larger amount of the leading portion 61.

[0053] Fifth Embodiment A flow path substrate 5 according to a fifth embodiment will be described below. The flow path substrate 5 is different from the flow path substrate 1 in the configuration of the detection unit 53. As shown in FIG. 8 , the detection unit 53 of the flow path substrate 5 does not have configurations corresponding to the second reservoir 134 and the fourth flow path 137 of the flow path substrate 1. In the detection unit 53 of the flow path substrate 5, the first flow path 532 and the second flow path 533 are connected to the outlet hole 14. In the detection unit 53 of the flow path substrate 5, the first flow path 532 and the second flow path 533 may be connected to the outside of the flow path substrate 5.

[0054] After the first reservoir 231 is filled with the specimen 60, the specimen 60 that has flowed into the first reservoir 231 from the third flow path 236 flows out from the first flow path 532 or the second flow path 533. Here, also in the flow path substrate 5 of this embodiment, the first flow path 532 is narrower than the second flow path 533. Therefore, the amount of specimen 60 flowing out per unit time from the first flow path 532 is less than the amount of specimen 60 flowing out per unit time from the second flow path 533. As a result, also in the flow path substrate 5 of this embodiment, the first reservoir 531 can store a larger amount of the leading end portion 61.

[0055] Sixth Embodiment A flow path substrate 1A according to a sixth embodiment will be described below with appropriate reference to the drawings. The flow path substrate 1A is a substrate used for detecting or quantifying a target substance contained in a sample. A flow path 10A is formed inside the flow path substrate 1A. When a sample is introduced into the flow path substrate 1A, the sample and a reagent are mixed inside the flow path substrate 1A. The sample mixed with the reagent is temporarily stored in a detection unit 13A. For example, "storage" refers to the sample remaining in a certain region relative to the flow in the flow path 10A, but is not limited to this.

[0056] For example, the specimen may include a substance derived from a living organism, such as a human, dog, cat, or cow. For example, the specimen may include a substance excreted or extracted from a living organism, such as urine, blood, sweat, saliva, or nasal secretions. For example, the target substance may be a virus, a bacterium, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), or a protein.

[0057] For example, the reagent may include a substrate that reacts with the target substance or a nucleic acid or enzyme contained in the target substance. For example, the reagent may include a substrate that emits fluorescence. For example, the reagent may include probe DNA or probe RNA designed to detect the target substance or a nucleic acid contained in the target substance. For example, the reagent may include primer DNA or an enzyme for amplifying the target substance or a nucleic acid contained in the target substance.

[0058] The configuration of the flow path substrate 1A will be described with reference to Figures 9, 10, 11, and 12. As shown in Figure 9, the flow path substrate 1A has a rectangular parallelepiped shape. For example, the flow path substrate 1A may have a curved surface, a spherical surface, a concave surface, or a convex surface in part. For example, the flow path substrate 1A may be made of a single member, or may be made by combining multiple members.

[0059] 10 , the flow path substrate 1A has a flow path 10A therein. The flow path 10A has an inlet hole 11A, a reagent dissolving section 12A, a detection section 13A, an outlet hole 14A, a branching section 15A, and a filter section 16A. The flow path 10A has a first flow path 101 as a first branching flow path and a second flow path 102 as a second branching flow path.

[0060] The flow path substrate 1A has a first surface 17A, which is the front surface of the flow path substrate 1A, and a second surface 18A, which is the back surface of the flow path substrate 1A relative to the first surface 17A. The top surface of the flow path 10A is the surface of the flow path 10A that is located on the first surface 17A side. The bottom surface of the flow path 10A is the surface of the flow path 10A that is located on the second surface 18A side. The side surface of the flow path 10A is the surface of the flow path 10A that is inclined with respect to the top surface and the bottom surface.

[0061] For example, the flow path substrate 1A may be made of resin, glass, ceramic, metal, or the like. The flow path substrate 1A may be made of a plurality of materials. For example, the flow path substrate 1A may be formed by injection molding, resin cutting, photolithography, or the like. The flow path 10A has a rectangular cross section perpendicular to the first surface 17A. For example, the flow path 10A may have a substantially circular, elliptical, trapezoidal, triangular, or other cross section perpendicular to the first surface 17A.

[0062] The inlet hole 11A can introduce a sample into the flow path 10A. The outlet hole 14A can discharge a sample from the flow path 10A to the outside of the flow path substrate 1A. The inlet hole 11A and the outlet hole 14A connect the outside of the flow path substrate 1A to the flow path 10A. The inlet hole 11A and the outlet hole 14A open to one of the surfaces of the flow path substrate 1A. For example, the inlet hole 11A or the outlet hole 14A opens to the first surface 17A of the flow path substrate 1A. The shapes of the inlet hole 11A and the outlet hole 14A can be selected arbitrarily. For example, the space located inside the inlet hole 11A or the outlet hole 14A may have a shape such as a truncated cone, a triangular pyramid, a square pyramid, a cylindrical shape, or a square prism shape.

[0063] The reagent dissolving section 12A has a reagent located on the bottom or side surface of the flow path, and can dissolve the reagent in the sample. The reagent dissolving section 12A is part of the second flow path 102. For example, the reagent dissolving section 12A is located in the second flow path 102 closer to the first flow path 101 than the bent section 103. The shape of the reagent dissolving section 12A can be selected arbitrarily. For example, the reagent dissolving section 12A has a linear or bent shape. For example, the reagent dissolving section 12A of this embodiment has a shape in which arc shapes and linear shapes are alternately repeated. In order for the reagent dissolving section 12A to dissolve the reagent in the sample, the reagent dissolving section 12A does not have to have a bent shape.

[0064] The detection unit 13A can store a specimen mixed with a reagent. For example, when a target substance is detected using light using the flow path substrate 1A, the surface of the detection unit 13A on the first surface 17A side and the surface of the detection unit 13A on the second surface 18A side may be light-transmitting. The flow path substrate 1A has a plurality of detection units 13A. The inlet hole 11A side of each of the plurality of detection units 13A is connected to the outlet hole 14A side of each of the second flow paths 102. Each of the plurality of detection units 13A also functions as a first storage unit connected to the second branch flow path.

[0065] The branching section 15A branches the flow path 10A into multiple paths. The branching section 15A branches the first flow path 101 into multiple second flow paths 102. The number of second flow paths 102 branching from the first flow path 101 is not limited to this and can be set to any number. The branching section 15A branches the second flow paths 102 so that the width of the second flow paths 102 is narrower than the width of the first flow path 101. The branching section 15A is located between the introduction hole 11A and the reagent dissolving section 12A.

[0066] The filter section 16A can separate solids or air bubbles contained in the sample. The filter section 16A is located between the introduction hole 11A and the branching section 15A. For example, the filter section 16A may be located between the branching section 15A and the reagent dissolving section 12A. The filter section 16A has the thickest region of the flow path 10A.

[0067] An overview of detecting a target substance contained in a sample using the flow path substrate 1A will be described. First, the sample is introduced into the flow path through the inlet 11A. The sample moving through the flow path 10A is distributed to multiple branched flow paths at the branching section 15A. The sample moving through each flow path is mixed with a reagent in the reagent dissolving section 12A. The sample mixed with the reagent in this manner is stored in the detection section 13A. The target substance is detected by observing the sample stored in the detection section 13A. For example, the reagent may contain a substrate that reacts with the target substance and emits fluorescence. In this case, the sample may be observed by irradiating the detection section 13A with excitation light. When observing the sample by irradiating the detection section 13A with excitation light, the target substance may be detected based on the fluorescence emitted from the substrate in the sample.

[0068] (First flow path 101) The first flow path 101 is capable of moving a liquid. The first flow path 101 is capable of moving a liquid in a first direction. For example, the first flow path 101 is capable of moving a specimen introduced from the inlet hole 11A to the branching section 15A. The first flow path 101 connects the inlet hole 11A and the branching section 15A. The thickness of the first flow path 101 may be constant or may vary. The thickness, width, and depth of the first flow path 101 may be set to any value. For example, the width of the first flow path 151 may be 200 μm to 1000 μm. For example, the depth of the first flow path 151 may be 25 μm to 200 μm.

[0069] (Second flow path 102) The second flow path 102 is capable of moving a liquid. The second flow path 102 is capable of moving a liquid in a first direction. For example, the second flow path 102 is capable of moving a sample that has flowed in from the first flow path 101 at the branching section 15A to the detection section 13A. The second flow path 102 is a flow path branched from the first flow path 101. The second flow path 102 connects the branching section 15A and the detection section 13A. The thickness of the second flow path 102 is thinner than the thickness of the first flow path 101. The thickness of the second flow path 102 may be constant or may vary. As long as the thickness of the second flow path 102 is thinner than the thickness of the first flow path 101, the thickness, width, and depth of the second flow path 102 may be set to any value. For example, the width of the second flow path 102 may be 20 μm to 500 μm. For example, the depth of the second flow path 102 may be 25 μm to 200 μm.

[0070] (Bent portion 103) The second flow path 102 has a bent portion 103. Each of the multiple second flow paths 102 has a bent portion 103. The bent portion 103 can reduce the concentration imbalance of a substance contained in a liquid passing through the interior thereof. For example, the bent portion 103 can reduce the concentration imbalance of a substance contained in a liquid passing through the interior thereof by mixing the liquid passing through the interior thereof. For example, the bent portion 103 can reduce the concentration imbalance of a substance contained in a liquid passing through the interior thereof by generating a flow in the liquid passing through the interior thereof.

[0071] The bent portion 103 may be located in one of two regions located in a direction perpendicular to an imaginary line overlapping the second flow path 102. For example, the "imaginary line overlapping the second flow path 102" refers to a line extending from any point within the second flow path 102 in the extension direction of the second flow path 102. For example, the "region located in a direction perpendicular to the imaginary line" refers to a region that overlaps the imaginary line or is located to the right or left of the imaginary line. For example, the bent portion 103 is located in one of two regions located in a direction perpendicular to an imaginary line that overlaps portions of the second flow path 102 located at both ends of the bent portion 103. For example, the bent portion 103 shown in FIG. 12 is located only in the left region of two regions located in a direction perpendicular to an imaginary line L1 that overlaps the right end of the second flow path 102.

[0072] The bent portion 103 may be located only in a direction perpendicular to a line segment located between both ends of the bent portion 103, of a virtual line L1 that overlaps the second flow path 102. For example, the bent portion 103 shown in FIG. 12 is located only in a region R1 that is located in a direction perpendicular to a line segment L2 that is located between both ends of the bent portion 103, of a virtual line L1 that overlaps the second flow path 102.

[0073] As shown in Fig. 12, the bending portion 103 has a shape bent along the longitudinal direction. For example, the "longitudinal direction" refers to the direction in which the width of the region R1 in which the bending portion 103 is located is larger, and refers to the up-and-down direction in Fig. 12. In this embodiment, the longitudinal direction of the bending portion 103 is the same as the extension direction of the second flow path 102 before and after the bending portion 103. For example, "bending along the longitudinal direction" refers to bending while extending only in either the upward or downward direction in Fig. 11. For example, "bending along the longitudinal direction" does not include a case in which a flow path extending downward is bent so as to extend upward.

[0074] Of the bent portions 103 included in each of the multiple second flow paths 102, some bent portions 103 may be located on the left side of the second flow path 102, and other bent portions 103 may be located on the right side of the second flow path 102. In this embodiment, of the bent portions 103 included in each of the four second flow paths 102, the two bent portions 103 located on the left side are located on the left side of the second flow path 102, and the two bent portions 103 located on the right side are located on the right side of the second flow path 102. For example, of the bent portions 103 included in each of the multiple second flow paths 102, some bent portions 103 may have a shape that is plane-symmetrical with respect to the other bent portions 103. As shown in FIG. 10 , in this embodiment, of the bent portions 103 included in each of the four second flow paths 102, the two bent portions 103 located on the right side are plane-symmetrical with respect to the two bent portions 103 located on the left side.

[0075] The bending portion 103 may have a planar shape such as a convex, U-shaped, L-shaped, or arc-shaped curve. For example, the bending portion 103 has a plurality of U-shaped flow paths 1031 bent into a U shape. For example, the bending portion 103 has a shape in which U-shaped flow paths 1031 are continuously inverted from side to side. The number of U-shaped flow paths 1031 in each of the plurality of bending portions 103 may be the same or different. In this embodiment, the plurality of bending portions 103 have the same number of U-shaped flow paths 1031. In other words, the plurality of bending portions 103 include a first bending portion and a second bending portion each having the same number of U-shaped flow paths 1031 as the bending flow path. In other words, the second bending portion has the same number of U-shaped flow paths 1031 as the first bending portion.

[0076] The width of the bent portion 103 in the direction perpendicular to the longitudinal direction may be set arbitrarily. For example, the width of the bent portion 103 in the direction perpendicular to the longitudinal direction may be two to three times the width of the second flow path 102.

[0077] 13 , the second flow path 102 has a narrow portion 104. Each of the plurality of second flow paths 102 has a narrow portion 104. The narrow portion 104 has a shape that becomes thinner as it approaches the detection unit 13A. By having a shape that becomes thinner as it approaches the detection unit 13A, the narrow portion 104 can slow down the flow rate of the liquid flowing toward the detection unit 13A.

[0078] Of the side surfaces of the second flow path 102, the side surface located on the right side is referred to as the first side surface 105, and the side surface located on the left side is referred to as the second side surface 106. In other words, the second side surface 106 is the side surface opposite to the first side surface 105. For example, the narrow portion 104 has a shape in which the width narrows as it approaches the storage portion 131A of the detection unit 13A, because the second side surface 106 has a shape inclined with respect to the first side surface 105.

[0079] For example, the width of the narrowest region of the narrow section 104 is smaller than half the width of the widest region of the second flow path 102. For example, the width of the narrowest region of the narrow section 104 is smaller than half the width of the widest region of the second flow path 102.

[0080] (Configuration of the detection unit 13A) The detection unit 13A has a storage unit 131A, a first discharge path 132A, and a second discharge path 133A. The storage unit 131A is capable of storing liquid. The first discharge path 132A and the second discharge path 133A are capable of passing gas or liquid flowing in from the storage unit 131A. The width of the first discharge path 132A is thinner than the width of the second discharge path 133A. The second discharge path 133A may be connected to one of the two side surfaces of the storage unit 131A. For example, the second discharge path 133A in this embodiment is connected to the side surface of the storage unit 131A that is closer to the second side surface 106.

[0081] (Mixing of Samples at Bent Section 103) The following describes the flow of mixing of samples by the bent section 103. After passing through the first flow path 101, the sample introduced from the inlet hole 11A is distributed to the multiple second flow paths 102 by the branch section 15A. Here, in the flow path substrate 1A of this embodiment, each of the multiple second flow paths 102 has a bent section 103 bent along the longitudinal direction. Therefore, compared to a flow path substrate in which only some of the multiple second flow paths have bent sections, it is possible to reduce the bias in concentration of substances contained in the sample flowing through each second flow path 102. Furthermore, compared to a flow path substrate having bent sections bent along a direction other than the longitudinal direction, it is possible to reduce the risk of solids or bubbles clogging the inside of the bent section 103.

[0082] In the flow path substrate 1A of this embodiment, each of the plurality of second flow paths 102 has a bent portion 103 that is bent along the longitudinal direction. As a result, it is possible to reduce the unevenness in the concentration of substances contained in the specimen flowing through each second flow path 102. It is also possible to reduce the risk of solids or air bubbles clogging the inside of the bent portion 103.

[0083] In the flow path substrate 1A of this embodiment, the narrow portion 104 has a shape in which the second side surface 106 is inclined with respect to the first side surface 105. Therefore, when the sample flows into the storage portion 131A, it is more likely to flow toward the first side surface 105. Furthermore, the second discharge path 133A is connected to the side of the two side surfaces of the storage portion 131A that is closer to the second side surface 106. As a result, the amount of sample flowing out from the first discharge path 132A can be reduced before the sample is stored in the storage portion 131A.

[0084] Seventh Embodiment A flow path substrate 2A according to a seventh embodiment will be described below. The flow path substrate 2A is different from the flow path substrate 1A in the configuration of a bent portion 203. As shown in Fig. 14, the bent portion 203 of the flow path substrate 2A has a straight flow path 2032 connected between two U-shaped flow paths 2031. A portion of the bent portion 203 of the flow path substrate 2A is wider in the direction perpendicular to the longitudinal direction than the bent portion 103 of the flow path substrate 1A.

[0085] The direct flow path 2032 extends in the left-right direction. The lengths of the multiple direct flow paths 2032 may be the same or different. The lengths of the multiple direct flow paths 2032 may be set to any value. The width of the direct flow path 2032 may be the same as or different from the width of the U-shaped flow path 2031. By having the direct flow path 2032, the flow path substrate 2A of this embodiment can lengthen the time it takes for the sample to flow through the bent portion 203.

[0086] Eighth Embodiment A flow path substrate 3A according to the eighth embodiment will be described below. The flow path substrate 3A is different from the flow path substrate 1A in the configuration of the bent portion 303. As shown in Fig. 15 , a part of the bent portion 303 of the flow path substrate 3A is a narrow portion 304. The bent portion 303 of the flow path substrate 3A has a region where the width or depth is reduced and the thickness is thereby narrowed.

[0087] In the bent portion 303, a portion of the plurality of U-shaped flow paths 3031 has a shape in which the width or depth is reduced, resulting in a tapered shape. The bent portion 303 may be set to any thickness, width, or depth as long as it has a region in which the thickness is tapered. In the flow path substrate 3A of the present embodiment, a portion of the bent portion 303 is the narrow portion 304, and therefore the area occupied by the bent portion 303 and the narrow portion 304 can be made smaller than in a flow path substrate having a bent portion and a narrow portion separately.

[0088] Ninth Embodiment A flow path substrate 1B according to a ninth embodiment will be described below with appropriate reference to the drawings. The flow path substrate 1B is a substrate used for detecting or quantifying a target substance contained in a specimen. A flow path 10B is formed inside the flow path substrate 1B as a fifth flow path. When a specimen is introduced into the flow path substrate 1B, the specimen and a reagent are mixed inside the flow path substrate 1B. The specimen mixed with the reagent is temporarily stored in the detection unit 13B. In other words, the detection unit 13B is capable of storing a liquid. For example, "storage" refers to the specimen remaining in a certain region relative to the flow in the flow path 10B, but is not limited to this.

[0089] For example, the specimen may include a substance derived from a living organism such as a human, dog, cat, or cow. For example, the specimen may include a substance excreted or extracted from a living organism, such as urine, blood, sweat, saliva, or nasal secretions. For example, the target substance may be a virus, a bacterium, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), or a protein.

[0090] For example, the reagent may include a substrate that reacts with the target substance or a nucleic acid or enzyme contained in the target substance. For example, the reagent may include a substrate that emits fluorescence. For example, the reagent may include probe DNA or probe RNA designed to detect the target substance or a nucleic acid contained in the target substance. For example, the reagent may include primer DNA or an enzyme for amplifying the target substance or a nucleic acid contained in the target substance.

[0091] The configuration of the flow path substrate 1B will be described with reference to Figures 16, 17, 18, and 19. As shown in Figure 16, the flow path substrate 1B has a rectangular parallelepiped shape. For example, the flow path substrate 1B may have a curved, spherical, concave, or convex shape in a portion thereof. For example, the flow path substrate 1B may be located in part or in whole inside a housing made of resin, metal, or the like. For example, the flow path substrate 1B may be made of a single member, or may be made by combining multiple members.

[0092] 17 , the flow path substrate 1B has a flow path 10B therein. The flow path 10B has an inlet hole 11B, a reagent dissolving section 12B, a detection section 13B, an outlet hole 14B, a branching section 15B, and a filter section 16B. The flow path 10B has a first flow path 101B as a first main flow path, a second flow path 102B as a second main flow path, and a third flow path 103B as a sub-flow path.

[0093] The flow path substrate 1B has a first surface 17B, which is the front surface of the flow path substrate 1B, and a second surface 18B, which is the back surface of the flow path substrate 1B relative to the first surface 17B. The top surface of the filter section 16B is the surface located on the first surface 17B side of each component. The bottom surface of the filter section 16B is the surface located on the second surface 18B side of each component. The side surface of the filter section 16B is the surface located between the top surface and the bottom surface of the filter section 16B.

[0094] For example, the material of the flow path substrate 1B may be resin, glass, ceramic, metal, etc. The flow path substrate 1B may be made of a plurality of materials. For example, the flow path substrate 1B may be formed by injection molding, resin cutting, photolithography, etc.

[0095] The inlet hole 11B can introduce a sample into the flow path 10B. The outlet hole 14B can discharge a sample from the flow path 10B to the outside of the flow path substrate 1B. The inlet hole 11B and the outlet hole 14B connect the outside of the flow path substrate 1B to the flow path 10B. The inlet hole 11B and the outlet hole 14B open to one of the surfaces of the flow path substrate 1B. For example, the inlet hole 11B or the outlet hole 14B opens to the first surface 17B of the flow path substrate 1B. The shapes of the inlet hole 11B and the outlet hole 14B can be selected arbitrarily. For example, the space located inside the inlet hole 11B or the outlet hole 14B may have a shape such as a truncated cone, a triangular pyramid, a square pyramid, a cylindrical shape, or a square prism shape.

[0096] The reagent dissolving section 12B is where the reagent is located and can dissolve the reagent in the specimen. In the reagent dissolving section 12B, the reagent is located on the bottom or side surface of the flow path. The shape of the reagent dissolving section 12B can be selected arbitrarily. For example, the reagent dissolving section 12B has a linear shape or a curved shape. For example, the reagent dissolving section 12B of this embodiment has a shape in which arc shapes and linear shapes are repeated alternately. In order for the reagent dissolving section 12B to dissolve the reagent in the specimen, the reagent dissolving section 12B does not have to have a curved shape.

[0097] The detection unit 13B can store a sample mixed with a reagent. For example, when a target substance is detected by light using the flow path substrate 1B, the surface of the detection unit 13B on the first surface 17B side and the surface of the detection unit 13B on the second surface 18B side may be light-transmitting.

[0098] The branching section 15B branches the second flow path 102B into multiple third flow paths 103B. The number of third flow paths 103B branched from the second flow path 102B can be set to any number. The branching section 15B branches the third flow path 103B so that the width of the third flow path 103B is narrower than the widths of the first flow path 101B and the second flow path 102B. The branching section 15B is located between the introduction hole 11B and the reagent dissolving section 12B. For example, the branching section 15B may be located between the reagent dissolving section 12B and the detection section 13B.

[0099] The first flow path 101B, the second flow path 102B, and the third flow path 103B are flow paths that extend in one plane. The first flow path 101B connects the introduction hole 11B and the filter section 16B. The second flow path 102B connects the filter section 16B and the branch section 15B. The third flow path 103B is a flow path branched from the second flow path 102B by the branch section 15B. The flow path 10B has multiple third flow paths 103B.

[0100] An overview of detecting a target substance contained in a sample using flow path substrate 1B will be described. First, the sample is introduced through inlet 11B. The sample moving through flow path 10B passes through filter section 16B. The sample that has passed through filter section 16B is mixed with a reagent in reagent dissolving section 12B. The sample mixed with the reagent in this manner is stored in detection section 13B. The target substance is detected by observing the sample stored in detection section 13B. For example, the reagent may contain a substrate that reacts with the target substance and emits fluorescence. In this case, the sample may be observed by irradiating detection section 13B with excitation light. While irradiating detection section 13B with excitation light, the target substance may be detected based on the fluorescence emitted from the substrate in the sample.

[0101] (Filter section 16B) The filter section 16B can separate solids or air bubbles from the specimen. For example, the filter section 16B can separate air bubbles generated when the specimen is introduced into the introduction hole 11B. For example, if the specimen is saliva, the filter section 16B can separate plaque, tartar, and the like contained in the saliva. For example, the filter section 16B may be able to separate solids or air bubbles larger than a certain size from the specimen.

[0102] The filter section 16B is located midway through the flow path 10B. The filter section 16B may be located between the introduction hole 11B and the detection section 13B. For example, the filter section 16B of this embodiment is located between the introduction hole 11B and the reagent dissolving section 12B. For example, the filter section 16B of this embodiment is located between the introduction hole 11B and the detection section 13B. For example, the filter section 16B of this embodiment is located between the introduction hole 11B and the branching section 15B. The filter section 16B has an inlet 162 as a filter inlet and an outlet 163 as a filter outlet. In the flow path substrate 1B of this embodiment, the inlet 162, the outlet 163, and the detection section 13B as a first storage section are located in this order.

[0103] The filter portion 16B is thicker than the flow path 10B. For example, the narrowest region of the filter portion 16B is thicker than the first flow path 101B and the second flow path 102B. For example, the widest region of the filter portion 16B is thicker than the widest region of the flow path 10B. For example, the ratio of the widest region of the filter portion 16B to the widest region of the flow path 10B, in other words, the width of the widest region of the filter portion 16B / the width of the widest region of the flow path 10B, may be 2.0 or greater. "Width" refers to the cross-sectional area in a plane perpendicular to the extension direction of the flow path. "Extension direction of the flow path" refers to the direction in which the spaces formed by the flow paths are continuously located. For example, "extension direction of the flow path" refers to the direction in which a fluid flows when the fluid is passed through the flow path, but is not limited thereto.

[0104] As long as the thickness of the filter portion 16B is greater than the thickness of the flow path 10B, the width and depth of the filter portion 16B may be set to any value. For example, the width of the filter portion 16B may be 500 μm to 1500 μm. For example, the width of the thickest region of the filter portion 16B may be 1000 μm to 1500 μm. For example, the depth of the filter portion 16B may be 25 μm to 200 μm. In this embodiment, the "depth of the filter portion 16B" refers to the distance between the top and bottom surfaces of the filter portion 16B, and corresponds to, for example, H1 in FIG. 20 .

[0105] In the filter section 16B, a region through which an imaginary line overlapping the inlet 162 and the outlet 163 passes is defined as a first region 164. In the filter section 16B, a second region 165 is defined as a region outside the first region 164 and located in a direction perpendicular to the imaginary line. The area of ​​the first region 164 may be larger or smaller than the area of ​​the second region 165. In this embodiment, the area of ​​the first region 164 is larger than the area of ​​the second region 165.

[0106] The filter portion 16B has protrusions 161 inside. The sample passes through the filter portion 16B by passing between the protrusions 161 or between the protrusions 161 and the side wall of the filter portion 16B. If the sample contains solids or bubbles, the protrusions 161 prevent the solids or bubbles from passing through the filter portion 16B. Thus, the protrusions 161 can separate the solids or bubbles from the sample.

[0107] In filter portion 16B, the area of ​​protrusions 161 in first region 164 is larger than the area of ​​protrusions 161 in second region 165. For example, in filter portion 16B, the ratio of the area of ​​protrusions 161 in first region 164 to the area of ​​protrusions 161 in second region 165, in other words, the ratio of the area of ​​protrusions 161 in first region 164 to the area of ​​protrusions 161 in second region 165, may be 1.2 or more.

[0108] The shape of the filter part 16B when viewed from above can be set to any shape. For example, the any shape may be a polygonal shape, a substantially circular shape, an elliptical shape, or a shape that combines multiple shapes. For example, the polygonal shape of the filter part 16B may be an octagonal shape, a hexagonal shape, a rectangular shape, or a trapezoidal shape. The filter part 16B of this embodiment has an octagonal shape when viewed from above.

[0109] The number of protrusions 161 may be one or may be two or more. The interval between adjacent protrusions 161 may be set to any value. For example, the interval between adjacent protrusions 161 may be 50 μm to 150 μm.

[0110] The protrusions 161 are arranged so as to be continuous with, or extend from, the inner wall of the filter portion 16B. For example, the protrusions 161 extend from the bottom surface of the filter portion 16B. For example, the protrusions 161 extend from the bottom surface of the filter portion 16B in a direction perpendicular to the bottom surface of the filter portion 16B. "Extending in a perpendicular direction" does not necessarily mean that the surface of the protrusions 161 is perpendicular to the bottom surface of the filter portion 16B, but rather it is sufficient that the protrusions 161 have a height in a direction perpendicular to the bottom surface of the filter portion 16B. For example, the protrusions 161 may extend from the top surface of the filter portion 16B. The protrusions 161 may or may not be in contact with the top surface of the filter portion 16B. In this embodiment, the protrusions 161 are in contact with the top surface of the filter portion 16B.

[0111] The distance between the protrusions 161 is smaller than the width of the inlet 162 and the outlet 163. In the protrusions 161 of this embodiment, the distance between the protrusions 161 is smaller than the width of the third flow path 103B. In the filter section 16B, the distance between the side surface of the filter section 16B and the protrusion 161 adjacent to the side surface of the filter section 16B is smaller than the width of the inlet 162 and the outlet 163. In the filter section 16B of this embodiment, the distance between the side surface of the filter section 16B and the protrusion 161 adjacent to the side surface of the filter section 16B is smaller than the width of the third flow path 103B.

[0112] The length of the protrusion 161 in a direction along an imaginary line overlapping the inlet 162 and the outlet 163 is longer than the length in a direction perpendicular to the imaginary line. The protrusion 161 has an elongated shape with the longitudinal direction being the direction along the imaginary line overlapping the inlet 162 and the outlet 163. The protrusion 161 has an elongated shape with the longitudinal direction being the extension direction of the filter section 16B.

[0113] 19 , the protrusion 161 has two first surfaces 1611, which are flat surfaces facing each other, and two second surfaces 1612, which are curved surfaces connecting the two first surfaces. The first surfaces 1611 face the side surfaces of the filter section 16B. The first surfaces 1611 extend along an imaginary line that overlaps with the inlet 162 and the outlet 163. The second surfaces 1612 are curved surfaces that are convex outward from the protrusion 161.

[0114] 20 , the cross section of the protrusion 161 parallel to the side surface of the filter portion 16B is trapezoidal. The cross section of the protrusion 161 parallel to the side surface of the filter portion 16B may be square, rectangular, semicircular, diamond-shaped, hexagonal, or the like.

[0115] The protrusion 161 has a bottom surface 1613 and an upper surface 1614. The bottom surface 1613 is a surface that faces the bottom surface of the filter portion 16B. The bottom surface 1613 may be integral with the bottom surface of the filter portion 16B. The upper surface 1614 is a surface that faces the upper surface of the filter portion 16B. The upper surface 1614 may be integral with the upper surface of the filter portion 16B. The bottom surface 1613 is a surface that is located on the first surface 17B side of the flow path substrate 1B. The upper surface 1614 is a surface that is located on the second surface 18B side of the flow path substrate 1B.

[0116] In the protrusion 161 of this embodiment, the area of ​​the bottom surface 1613 is larger than the area of ​​the top surface 1614. The area of ​​the bottom surface 1613 may be the same as or smaller than the area of ​​the top surface 1614. Any shape may be selected for the bottom surface 1613 and the top surface 1614. In the protrusion 161 of this embodiment, the shape of the bottom surface 1613 and the top surface 1614 is a rectangle with four rounded corners. For example, the shape of the bottom surface 1613 and the top surface 1614 may be a shape in which opposing sides of a rectangle are joined to semicircles with the sides as their diameters. For example, the shape of the bottom surface 1613 and the top surface 1614 may be a rectangle, a square, a trapezoid, an ellipse, a substantially circular shape, or the like.

[0117] Filter unit 16B has a first portion 166 connected to flow path 10B at inlet 162. First portion 166 is the portion through which the sample flowing in from inlet 162 first passes. The thickness of first portion 166 is configured to increase with increasing distance from inlet 162. As the sample flowing in from inlet 162 passes through first portion 166, which gradually increases in thickness, the change in pressure on the sample becomes gradual. As a result, filter unit 16B, by including first portion 166, can prevent turbulence in the flow of the sample when the sample flows in from inlet 162, reducing the risk of air bubbles being generated.

[0118] The width of the first portion 166 is configured to increase with increasing distance from the inlet 162. The first portion 166 of this embodiment has a region whose width increases to the left and right with increasing distance from the inlet 162. For example, the first portion 166 may have a region whose width increases only to the left or right with increasing distance from the inlet 162. The shape of the first portion 166 of this embodiment when viewed from above is trapezoidal. The shape of the first portion 166 when viewed from above is not limited to a trapezoid, and for example, any of the sides may include a curve.

[0119] Filter unit 16B has second portion 167 connected to flow path 10B at outlet 163. Second portion 167 is the last portion through which the sample flows out of outlet 163 before flowing out. The thickness of second portion 167 is configured to become thinner as it approaches outlet 163. The sample flowing into outlet 163 passes through second portion 167, which becomes gradually thinner, and the change in pressure applied to the sample is gradual. As a result, filter unit 16B can prevent turbulence of the flow of the sample as it flows into outlet 163, reducing the risk of air bubbles being generated.

[0120] The width of the second portion 167 is configured to become narrower as it approaches the outlet 163. The second portion 167 of this embodiment has a region where the width narrows so as to narrow from the left and right toward the outlet 163. For example, the second portion 167 may have a region where the width narrows so as to narrow only from the left or right toward the outlet 163. The second portion 167 of this embodiment has a trapezoidal shape when viewed from above. The shape of the second portion 167 when viewed from above is not limited to a trapezoid, and for example, any of the sides may include a curve.

[0121] Filter unit 16B has third portion 168 located between first portion 166 and second portion 167. Third portion 168 is the portion where protrusion 161 is located. Third portion 168 connects first portion 166 and second portion 167. Third portion 168 is the portion into which the analyte flowing out from first portion 166 flows. The analyte flowing out from third portion 168 flows into second portion 167.

[0122] In the third portion 168, the distance between the side surface of the third portion 168 and the protrusion 161 adjacent to the side surface of the third portion 168 is smaller than the width of the outlet 163. In the third portion 168, the distance between the side surface of the third portion 168 and the protrusion 161 adjacent to the side surface of the third portion 168 is smaller than the widths of the first flow path 101B and the second flow path 102B. In the third portion 168, the distance between the side surface of the third portion 168 and the protrusion 161 adjacent to the side surface of the third portion 168 is smaller than the width of the third flow path 103B. In the third portion 168, the distance between the side surface of the third portion 168 and the protrusion 161 adjacent to the side surface of the third portion 168 is smaller than the width of the narrowest region of the flow path 10B.

[0123] The third portion 168 has the thickest region of the filter portion 16B. The third portion 168 has the widest region of the filter portion 16B. In this embodiment, the third portion 168 has a rectangular shape when viewed from above. The shape of the third portion 168 when viewed from above is not limited to a rectangle, and for example, any side may include a curve. The width of the third portion 168 may be constant or may vary.

[0124] (Separation of solids or bubbles by filter section 16B) The following describes the process of separating solids or bubbles from a specimen by filter section 16B. The specimen that flows into filter section 16B from inlet 162 passes between protrusions 161 and then flows out from outlet 163. At this time, the amount of specimen that passes through first region 164 is greater than the amount of specimen that passes through second region 165. Therefore, if the specimen contains solids or bubbles, the solids or bubbles are more likely to pass through first region 164.

[0125] In the flow path substrate 1B of this embodiment, the area of ​​the protrusions 161 in the first region 164 is larger than the area of ​​the protrusions 161 in the second region 165. In other words, more of the protrusions 161 are located in the first region 164, where there is a high possibility that solids or bubbles will pass through. As a result, the protrusions 161 can more effectively separate the solids or bubbles from the specimen.

[0126] The flow path substrate 1B of this embodiment has a filter unit 16B. The filter unit 16B has a first region 164 through which an imaginary line overlapping an inlet 162 and an outlet 163 passes. The filter unit 16B has a second region 165 located outside the first region 164 and perpendicular to the imaginary line. In the filter unit 16B, the area of ​​the protrusions 161 in the first region 164 is larger than the area of ​​the protrusions 161 in the second region 165. As a result, the filter unit 16B can more effectively separate solids or bubbles from the specimen.

[0127] Tenth Embodiment A flow path substrate 2B according to a tenth embodiment will now be described. The flow path substrate 2B is different from the flow path substrate 1B in the configuration of the filter portion 26B. As shown in Fig. 21 , the filter portion 26B of the flow path substrate 2B does not have a first portion 166 or a second portion 167, as compared to the filter portion 16B of the flow path substrate 1B. As shown in Figs. 21 and 22 , the filter portion 26B of the flow path substrate 2B is different from the filter portion 16B of the flow path substrate 1B in the structure of the protrusions 261.

[0128] The filter portion 26B has a rectangular shape when viewed from above. The width of the filter portion 26B is constant. The protrusions 261 also have a rectangular shape when viewed from above. In the filter portion 26B, the width between the protrusions 261 is smaller than the distance between the side surface of the filter portion 26B and the protrusion 261 adjacent to the side surface of the filter portion 26B.

[0129] The protrusion 261 has a gap between the upper surface 2614 and the upper surface of the flow channel 20B. The protrusion 261 may have a gap between the lower surface 2615 and the bottom surface of the flow channel 20B. The height of the protrusion 261 in a direction perpendicular to the bottom surface of the flow channel 20B is smaller than the depth of the flow channel 20B. In the flow channel substrate 2B of this embodiment, the filter section 26B can also more effectively separate solids or bubbles from the specimen.

[0130] Eleventh Embodiment A flow path substrate 3B according to an eleventh embodiment will now be described. The flow path substrate 3B is different from the flow path substrate 1B in the configuration of the filter section 36B. As shown in FIG. 23 , the filter section 36B of the flow path substrate 3B is different from the filter section 16B of the flow path substrate 1B in the structure of the first portion 366. The filter section 36B of the flow path substrate 3B is different from the filter section 16B of the flow path substrate 1B in the position of the protrusion 361.

[0131] In the filter unit 36B, the first portion 366 and the second portion 367 have different shapes. The side surface of the first portion 366 is curved and convex outward. The side surface of the second portion 367 is flat. In the filter unit 36B, the protrusions 361 are located in the first portion 366 and the third portion 368. The density of the protrusions 361 closer to the inlet 362 is lower than the density of the protrusions 361 closer to the outlet 363. The spacing between the protrusions 361 closer to the inlet 362 is greater than the spacing between the protrusions 361 closer to the outlet 363. In the flow path substrate 3B of this embodiment as well, the filter unit 36B can more effectively separate solids or bubbles from the specimen.

[0132] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art could easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure.

[0133] For example, while the flow path substrate 1 has been described as having a reagent dissolving section 12, this is not limiting. The flow path substrate 1 may not have the reagent dissolving section 12. In this case, the sample 60 introduced through the inlet 11 is stored in the detection section 13 without being mixed with a reagent or the like. Even in this case, most of the sample 60 stored in the detection section 13 can be stored in the detection section 13 without being replaced by sample 60 that flows in later. As a result, the detection accuracy of the target substance in the detection section 13 can be stabilized. For example, the detection section 13 may include a surface acoustic wave sensor having an antibody capable of binding to the target substance. For example, if the detection section 13 includes a surface acoustic wave sensor, the target substance may be detected by observing a change in surface acoustic wave caused by binding of the target substance to the antibody.

[0134] Furthermore, for example, the flow path substrate 1A has been described as having the reagent dissolving section 12A, but this is not limiting. The second flow path 102 does not have to have the reagent dissolving section 12A. In this case, for example, the sample and the reagent may be mixed before being introduced through the introduction hole 11A. The sample introduced through the introduction hole 11A is mixed by the bent section 103.

[0135] Furthermore, for example, the flow path substrate 1B has been described as having a branching portion 15B, but this is not limiting. The flow path substrate 1B may not have a branching portion 15B. In this case, the flow path 10B does not have a third flow path 103B branching from the second flow path 102B. The sample introduced through the introduction hole 11B passes through the filter portion 16B and is then stored in one detection portion 13B.

[0136] Additionally, for example, in the above description, the flow path substrate 1B has the filter portion 16B positioned between the introduction hole 11B and the branch portion 15B, but the present invention is not limited to this. The flow path substrate 1B may have a configuration in which the filter portion 16B is positioned between the detection portion 13B and the branch portion 15B. In the flow path substrate 1B of this embodiment, the filter portion 16B may be provided midway along each of the third flow paths 103B. The flow path substrate 1B of this embodiment may have multiple filter portions 16B.

[0137] 1, 2, 3, 4, 5 Flow path substrate 10 Flow path 101 First flow path 102 Second flow path 103, 203, 303 Bent portion 1031, 2031, 3031 U-shaped flow path 2032 Straight flow path 104, 304 Narrow portion 105 First side surface 106 Second side surface 11 Inlet hole 12 Reagent dissolving portion 13, 23, 33, 43, 53 Detection portion 131, 231, 331, 431, 531 First storage portion 132, 332, 432, 532 First flow path 133, 233, 333, 433, 533 Second flow path 134, 434 Second storage portion 135 Inlet 136, 236 Third flow path 137, 437 Fourth flow path 14 Outlet hole 15 Branch part 151 First channel 16 Filter part 161, 261, 361 Protrusion 1613 Bottom surface 1614, 2614 Top surface 2615 Bottom surface 162, 362 Inlet 163, 363 Outlet 164 First region 165 Second region 166, 366 First part 167, 367 2nd part 168, 368 3rd part 17 1st surface 18 2nd surface60 Sample 61 First part

Claims

1. A first storage section capable of storing the fluid that enters from the inlet, The first storage section is connected to a first channel and a second channel, respectively. The system comprises a first flow path and a second storage section connected to the second flow path, The first channel is connected to the first reservoir at a position further away from the inlet than the second channel, and is a channel substrate that is narrower than the second channel.

2. The flow channel substrate according to claim 1, wherein the second storage section is capable of storing fluid flowing in from the first flow channel and the second flow channel.

3. The flow channel substrate according to claim 1, wherein the second storage section is capable of storing fluids that flow out from the first storage section and fluids that flow in from the first flow channel and the second flow channel.

4. The flow channel substrate according to claim 1, wherein the first storage section is wider than the second flow channel.

5. The channel substrate according to claim 1, further comprising a third channel connected to the inlet.

6. The connection between the first storage section and the first flow path is defined as the first connection section. If the direction in which the fluid flows from the inlet to the first connection is defined as the first direction, The flow channel substrate according to claim 5, wherein the first storage portion has a region in which the cross-sectional area decreases in the first direction.

7. The connection between the first storage section and the first flow path is defined as the first connection section. If the direction in which the fluid flows from the inlet to the first connection is defined as the first direction, The flow channel substrate according to claim 5, wherein the length of the first storage portion in the first direction is greater than the length of the first storage portion in the direction perpendicular to the first direction.

8. The channel substrate according to claim 5, wherein the third channel is wider than the second channel.

9. The channel substrate according to claim 1, further comprising a fourth channel connected to the second storage section.

10. The channel substrate according to claim 9, wherein the fourth channel is connected to the outside of the channel substrate.

11. The channel substrate according to claim 9, wherein the fourth channel is wider than the first channel.

12. The connection between the second storage section and the second flow path is designated as the third connection section. The connection between the second storage section and the fourth flow path is designated as the fourth connection section. If the direction in which the fluid flows from the third connection to the fourth connection is defined as the second direction, The flow channel substrate according to claim 9, wherein the second storage portion has a region in which the cross-sectional area decreases toward the second direction.

13. The channel substrate according to claim 1, wherein the length of the first channel is longer than the length of the second channel.

14. The flow path substrate according to claim 1, wherein the second flow path is connected to the second storage section at a position opposite to the first flow path.

15. A first branch channel through which liquid can be moved, The device further includes a branching section that branches the first branching channel into a plurality of second branching channels, The system has a plurality of first storage units connected to the plurality of second branch channels, The channel substrate according to claim 1, wherein each of the plurality of second branch channels has a bent portion that is bent along the longitudinal direction.

16. The channel substrate according to claim 15, wherein the second branch channel is located on which a reagent for detecting a target substance contained in the liquid is located.

17. The channel substrate according to claim 16, wherein the reagent is located in the second branch channel on the side of the first branch channel rather than the bent portion.

18. The bent portion has a shape in which multiple bent channels are continuous, Having multiple bent portions, The flow channel substrate according to claim 15, wherein the plurality of bent portions include a first bent portion and a second bent portion having the same number of bent flow channels as the first bent portion.

19. Having multiple bent portions, The flow channel substrate according to claim 15, wherein the plurality of bent portions include a first bent portion and a second bent portion having a shape symmetrical to the first bent portion.

20. The channel substrate according to claim 15, wherein the width of the bent portion in a direction perpendicular to the longitudinal direction is less than or equal to three times the width of the second branch channel.

21. The flow channel substrate according to claim 15, wherein the longitudinal direction of the bent portion is the same as the extension direction of the second branched flow channel before and after the bent portion.

22. The channel substrate according to claim 15, wherein the bent portion is located in only one of two regions that are perpendicular to the virtual straight line that overlaps with the second branch channel.

23. The flow channel substrate according to claim 22, wherein the bent portion is located only in a direction perpendicular to the line segment of the virtual straight line located between the two ends of the bent portion.

24. The channel substrate according to claim 15, wherein the second branch channel has a narrowed portion which is a region that narrows in width as it approaches the first storage portion.

25. The first storage section further has a connected discharge passage on its side, The narrowed portion has a shape in which its width narrows only toward the first side, which is one of the two sides of the second branch channel. The flow path substrate according to claim 24, wherein the discharge passage is connected to the side surface of the first storage portion that is opposite to the first side surface.

26. The channel substrate according to claim 24, wherein the width of the narrowest region in the narrow portion is less than half the width of the widest region of the second branch channel.

27. A fifth channel extending in a single plane, It has a filter section that is wider than the fifth channel and is located in the middle of the fifth channel, and has a projection inside that extends in a direction perpendicular to the plane, The filter section has a filter inlet and a filter outlet. The area of ​​the protrusion in the first region through which a virtual straight line overlapping the filter inlet and the filter outlet passes is larger than the area of ​​the protrusion in the second region located outside the first region and perpendicular to the virtual straight line. The flow path substrate according to claim 1, wherein the filter inlet, the filter outlet, and the first storage section are located in order from the side of the inlet.

28. The flow channel substrate according to claim 27, wherein when the filter portion is viewed from above, the area of ​​the first region is larger than the area of ​​the second region.

29. The aforementioned filter section is A first portion is connected to the fifth flow path at the filter inlet and is configured to become wider as it moves away from the filter inlet, A second portion is connected to the fifth flow path at the filter outlet and is configured to become narrower as it approaches the filter outlet, A flow channel substrate according to claim 27, having the following characteristics.

30. The flow path substrate according to claim 29, wherein the filter portion is located between the first portion and the second portion and has a third portion on which the projection is located.

31. The flow path substrate according to claim 30, wherein the distance between the side surface of the third portion and the projection adjacent to the side surface of the third portion is smaller than the width of the filter outlet.

32. The flow channel substrate according to claim 29, wherein, when viewed from the filter inlet, the first portion has a region that widens to the left and right from the filter inlet.

33. The flow channel substrate according to claim 29, wherein, when viewed from the filter inlet, the second portion has a region in which the width narrows so as to be narrowed from the left and right toward the filter outlet.

34. The flow channel substrate according to claim 27, wherein the projection has two first surfaces which are planes facing each other, and two second surfaces which are curved surfaces which connect the two first surfaces.

35. The flow path substrate according to claim 34, wherein the first surface is opposite to the side surface of the filter portion.

36. An inlet for receiving liquid, A first main channel connected to the aforementioned inlet hole, The filter section connected to the first main flow path, A second main channel connected to the filter section, It has a branching section that branches the second main channel into a plurality of subchannels, The flow path substrate according to claim 27, wherein the inlet hole, the filter section, and the branching section are located in that order.

37. The width of the subchannel is narrower than the width of the first main channel and the second main channel. The filter portion has a plurality of protrusions, The channel substrate according to claim 36, wherein the spacing between each of the plurality of protrusions is smaller than the width of the subchannel.

38. The flow path substrate according to claim 36, wherein the distance between the filter portion and the projection adjacent to the side surface of the filter portion is smaller than the width of the sub-flow path.

39. An inlet for receiving liquid, A first main channel connected to the aforementioned inlet hole, The filter section connected to the first main flow path, A second main channel connected to the filter section, It has a detection unit connected to the second main channel and capable of storing liquid, The flow channel substrate according to claim 27, wherein the inlet hole, the filter section, and the detection section are arranged in that order.

40. The flow channel substrate according to claim 27, wherein the area of ​​the bottom surface of the projection is larger than the area of ​​the top surface of the projection.

41. The flow path substrate according to claim 27, wherein the cross-section of the projection parallel to the side surface of the filter portion is trapezoidal.