Abstract: A particle separation device comprises, inside a plate-like base body, a straight main flow path including a flow inlet and a plurality of branch flow paths. The flow inlet includes a sample flow inlet and a pressing flow inlet. The sample flow inlet is connected to the main flow path via a first bending part, a first straight part, a second bending part, and a second straight part. Widths in the first bending part and the first straight part are larger than widths in the second bending part and the second straight part. The widths in the second bending part and the second straight part are larger than a width in the main flow path. The pressing flow inlet is connected to the side surface of the main flow path via a third straight part, a third bending part, a fourth straight part, and a fifth straight part.

Abstract: A second device includes a first surface, a second surface in contact with a first device, and a first hole extending through and between the first and second surfaces and being continuous with a groove on the first device. A third device includes a third surface in contact with the first surface, a second hole open in the third surface and continuous with the first hole, and a flow path continuous with the second hole and open in the third surface. As viewed in a first direction from the first to second surfaces, the second hole has a diameter greater than a width of the flow path. The first hole has a greater diameter than the second hole. The second hole has a center surrounded by the first hole. The flow path intersects with the first hole at not more than one point or does not intersect with it.

Abstract: A second device includes a first surface, a second surface in contact with a first device, and a first hole extending through and between the first surface and the second surface and being continuous with a groove on the first device. A third device includes a third surface in contact with the first surface, a second hole open in the third surface and continuous with the first hole, and a flow path continuous with the second hole and open in the third surface. As viewed in a first direction from the first surface to the second surface, the first hole includes at least one vertex surrounded by the second hole, and a pair of sides joined to the at least one vertex and widening toward the flow path to define a minor angle.

Abstract: A flow path device comprises a plate-like measurement flow path device and a plate-like separation flow path device. The measurement flow path device includes a first flow path for measuring specific particles on a first fluid and connected to a third flow path and a second flow path for correction and passing a second fluid, not including the specific particles. The separation flow path device includes a fourth flow path for separating and selecting the specific particles from a sample and collecting a fluid. The separation flow path device is on the measurement flow path device's upper surface. The sample passes through a fifth flow path, the upper surface's opening, and flows into the fourth flow path from an opening in the separation flow path device's lower surface. The first fluid passes through the lower surface's opening, and flows into the first flow path from the upper surface's opening.

Abstract: A flow path device comprises a plate-like measurement flow path device and a plate-like separation flow path device. The measurement flow path device includes a first flow path for measuring specific particles on a first fluid and connected to a third flow path and a second flow path for correction and passing a second fluid, not including the specific particles. The separation flow path device includes a fourth flow path for separating and selecting the specific particles from a sample and collecting a fluid. The separation flow path device is on the measurement flow path device's upper surface. The sample passes through a fifth flow path, the upper surface's opening, and flows into the fourth flow path from an opening in the separation flow path device's lower surface. The first fluid passes through the lower surface's opening, and flows into the first flow path from the upper surface's opening.

Abstract: An inspection flow path device according to the present disclosure comprises: a first flow path device having a plate-like shape and including a pair of first surfaces located opposite to each other in a thickness direction and a first flow path located inside and including a first opening located in the pair of first surfaces and a branch flow path; and a second flow path device having a plate-like shape and translucency and including a pair of second surfaces located opposite to each other in a thickness direction and a second flow path located inside and including a second opening located in the pair of second surfaces; wherein one of the pair of first surfaces of the first flow path device is located on one of the pair of second surfaces of the second flow path device, and the first opening and the second opening are connected to each other.

Abstract: A measurement apparatus according to the present disclosure is a measurement apparatus capable of measuring particles in a fluid and comprises: a flow path device including a first flow path with translucency through which a first fluid including the particles passes and a second flow path with translucency through which a second fluid which does not include the particles passes; an optical sensor facing the flow path device, irradiating each of the first flow path and the second flow path with light, and receiving light passing through each of the first flow path and the second flow path; and a controller measuring the particles by comparing an intensity of light passing through the first flow path and an intensity of light passing through the second flow path, each of which is obtained by the optical sensor.

Abstract: A particle separation device comprises, inside a plate-like base body, a straight main flow path including a flow inlet and a plurality of branch flow paths. The flow inlet includes a sample flow inlet and a pressing flow inlet. The sample flow inlet is connected to the main flow path via a first bending part, a first straight part, a second bending part, and a second straight part. Widths in the first bending part and the first straight part are larger than widths in the second bending part and the second straight part. The widths in the second bending part and the second straight part are larger than a width in the main flow path. The pressing flow inlet is connected to the side surface of the main flow path via a third straight part, a third bending part, a fourth straight part, and a fifth straight part.

Abstract: A measurement apparatus according to the present disclosure is a measurement apparatus capable of measuring particles in a fluid and comprises: a flow path device including a first flow path with translucency through which a first fluid including the particles passes and a second flow path with translucency through which a second fluid which does not include the particles passes; an optical sensor facing the flow path device, irradiating each of the first flow path and the second flow path with light, and receiving light passing through each of the first flow path and the second flow path; and a controller measuring the particles by comparing an intensity of light passing through the first flow path and an intensity of light passing through the second flow path, each of which is obtained by the optical sensor.

Abstract: An inspection flow path device according to the present disclosure comprises: a first flow path device having a plate-like shape and including a pair of first surfaces located opposite to each other in a thickness direction and a first flow path located inside and including a first opening located in the pair of first surfaces and a branch flow path; and a second flow path device having a plate-like shape and translucency and including a pair of second surfaces located opposite to each other in a thickness direction and a second flow path located inside and including a second opening located in the pair of second surfaces; wherein one of the pair of first surfaces of the first flow path device is located on one of the pair of second surfaces of the second flow path device, and the first opening and the second opening are connected to each other.

Abstract: A particle separation device comprises a first flow path including a flow inlet, a second flow path connected to the first flow path, and a plurality of branch flow paths. Each of the plurality of branch flow paths is connected to the second flow path, and includes a flow outlet. The first flow path includes a bending unit, a first unit, and a second unit. In the bending unit, a direction in which a flow path extends is bent in a planar view. The first unit is located adjacent to the bending unit and closer to a flow inlet than the bending unit. The second unit is located adjacent to the bending unit and closer to a second flow path than the bending unit. A width of the second unit in the first flow path is smaller than a width of the first unit in the first flow path.

Abstract: A fine particle counter includes a light emitting element, a light receiving element, a mirror and a flow path. The mirror is capable of reflecting light emitted from the light emitting element to the light receiving element. The flow path is located between the mirror and a part including the light emitting element and the light receiving element.